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1

SDI: setting the record straight

After a few introductory remarks, Mr. Adelman first discusses Soviet propaganda against SDI. He then poses and answers questions regarding the following: SDI and the ABM Treaty; SDI and US arms control objectives; and the ethics of SDI. The final portion of the address reviews US nonproliferation efforts.

Adelman, K.L.

1985-01-01

2

Recent efforts to redefine the Strategic Defense Initiative (SDI) are mostly aimed at building support for a system to defend US land-based missiles. This is thought to be a more feasible goal than President Reagan's dream of an impregnable shield to defend the US population against ballistic missiles. But a feasible idea is not necessarily a good one. While chasing the population-defense fantasy would destroy the existing arms control regime and waste the national treasure of money and talent, defending land-based missiles would be dangerous and destabilizing. Defense Secretary Caspar Weinberger held fast to the idea of population defense in January, when he told the Senate Armed Services Committee that even early deployments of SDI systems that could be developed in the near future should be the first phase of a system that would protect the continent. But such statements may reflect the administration's determination to do away with the 1972 Anti-Ballistic Missile Treaty more than its belief that population defense is a reasonable goal. The author notes that, to those longstanding problems of defense decision making, they must now add the pressures of SDI. Furthermore, whatever the motives of those who advocate redirecting SDI, it is clear that concerns about the vulnerability of land-based missiles could be addressed in more sensible ways. 5 references.

Marsh, G.E.

1987-03-01

3

Recent efforts to redefine the Strategic Defense Initiative (SDI) are mostly aimed at building support for a system to defend US land-based missiles. This is thought to be a more feasible goal than President Reagan's dream of an impregnable shield to defend the US population against ballistic missiles. But a feasible idea is not necessarily a good one. While chasing

1987-01-01

4

Statistics of football dynamics

We investigate the dynamics of football matches. Our goal is to characterize statistically the temporal sequence of ball movements in this collective sport game, searching for traits of complex behavior. Data were collected over a variety of matches in South American, European and World championships throughout 2005 and 2006. We show that the statistics of ball touches presents power-law tails and can be described by $q$-gamma distributions. To explain such behavior we propose a model that provides information on the characteristics of football dynamics. Furthermore, we discuss the statistics of duration of out-of-play intervals, not directly related to the previous scenario.

Mendes, R S; Anteneodo, C

2007-01-01

5

Statistics as a dynamical attractor

It is demonstrated that any statistics can be represented by an attractor of the solution to a corresponding systen of ODE coupled with its Liouville equation. Such a non-Newtonian representation allows one to reduce foundations of statistics to better established foundations of ODE. In addition to that, evolution to the attractor reveals possible micro-mechanisms driving random events to the final distribution of the corresponding statistical law. Special attention is concentrated upon the power law and its dynamical interpretation: it is demonstrated that the underlying dynamics supports a " violent reputation" of the power law statistics.

Zak, Michail

2012-01-01

6

Statistics as a dynamical attractor

It is demonstrated that any statistics can be represented by an attractor of the solution to a corresponding systen of ODE coupled with its Liouville equation. Such a non-Newtonian representation allows one to reduce foundations of statistics to better established foundations of ODE. In addition to that, evolution to the attractor reveals possible micro-mechanisms driving random events to the final distribution of the corresponding statistical law. Special attention is concentrated upon the power law and its dynamical interpretation: it is demonstrated that the underlying dynamics supports a " violent reputation" of the power law statistics.

Michail Zak

2012-08-30

7

The Savannah River Remediation (SRR) Organization requested that Savannah River National Laboratory (SRNL) develop a Computational Fluid Dynamics (CFD) method to mix and blend the miscible contents of the blend tanks to ensure the contents are properly blended before they are transferred from the blend tank; such as, Tank 50H, to the Salt Waste Processing Facility (SWPF) feed tank. The work described here consists of two modeling areas. They are the mixing modeling analysis during miscible liquid blending operation, and the flow pattern analysis during transfer operation of the blended liquid. The transient CFD governing equations consisting of three momentum equations, one mass balance, two turbulence transport equations for kinetic energy and dissipation rate, and one species transport were solved by an iterative technique until the species concentrations of tank fluid were in equilibrium. The steady-state flow solutions for the entire tank fluid were used for flow pattern analysis, for velocity scaling analysis, and the initial conditions for transient blending calculations. A series of the modeling calculations were performed to estimate the blending times for various jet flow conditions, and to investigate the impact of the cooling coils on the blending time of the tank contents. The modeling results were benchmarked against the pilot scale test results. All of the flow and mixing models were performed with the nozzles installed at the mid-elevation, and parallel to the tank wall. From the CFD modeling calculations, the main results are summarized as follows: (1) The benchmark analyses for the CFD flow velocity and blending models demonstrate their consistency with Engineering Development Laboratory (EDL) and literature test results in terms of local velocity measurements and experimental observations. Thus, an application of the established criterion to SRS full scale tank will provide a better, physically-based estimate of the required mixing time, and elevation of transfer pump for minimum sludge disturbance. (2) An empirical equation for a tank with no cooling coils agrees reasonably with the current modeling results for the dual jet. (3) From the sensitivity study of the cooling coils, it was found that the tank mixing time for the coiled tank was about two times longer than that of the tank fluid with no coils under the 1/10th scale, while the coiled tank required only 50% longer than the one without coils under the full scale Tank 50H. In addition, the time difference is reduced when the pumping U{sub o}d{sub o} value is increased for a given tank. (4) The blending time for T-shape dual jet pump is about 20% longer than that of 15{sup o} upward V-shape pump under the 1/10th pilot-scale tank, while the time difference between the two pumps is about 12% for the full-scale Tank 50H. These results are consistent with the literature information. (5) A transfer pump with a solid-plate suction screen operating at 130 gpm can be located 9.5 inches above settled sludge for 2 in screen height in a 85 ft waste tank without disturbing any sludge. Detailed results are summarized in Table 13. Final pump performance calculations were made by using the established CW pump design, and operating conditions to satisfy the two requirements of minimum sludge disturbance, and adequate blending of tank contents. The final calculation results show that the blending times for the coiled and uncoiled tanks coupled with the CW pump design are 159 and 83 minutes, respectively. All the results are provided in Table 16.

Lee, S.

2011-05-05

8

Statistical Equilibrium Dynamics

The mean-field thermodynamic limit is studied for a class of isolated Newtonian N-body systems whose Hamiltonian admits several invariants of motion. It is shown that the macrostates of individual members of a statistical equilibrium ensemble are not necessarily themselves in a state of global thermal equilibrium in the strict sense. Yet they are always locally in thermodynamic equilibrium, and always global maximizers of the pertinent maximum entropy principle.

Michael K. -H. Kiessling

2008-05-03

9

The Evaluation of SISMAKOM (Computerized SDI Project).

ERIC Educational Resources Information Center

A survey of 88 users of SISMAKOM, a computerized selective dissemination of information (SDI) and document delivery service provided by the Universiti Sains Malaysia and four other Malaysian universities, was conducted in August 1982 in order to collect data about SISMAKOM and to assess the value of a computerized SDI service in a developing…

University of Science, Penang (Malaysia).

10

ERIC Educational Resources Information Center

The impetus for the nation-wide study of SDI (Selective Dissemination of Information) came from the desire to learn more about the options available for the application of the SDI concept prior to decisions about its possible use in Air Force research and development activities. For this purpose, data on user populations, literature coverage,…

Hoshovsky, Alexander G.

11

The SDI and European security interests

This paper examines Europe's reactions to President Reagan's Strategic Defense Initiative (SDI). On the one hand, the American proposals have inspired forceful European opposition of a kind potentially damaging to Alliance solidarity. On the other, paradoxically, the debate occurred in a period of rare Alliance harmony, when the deployment of cruise and Pershing II missiles was satisfactorily completed despite Soviet

Deschamps

1987-01-01

12

Operational Results of an Adaptive SDI System.

ERIC Educational Resources Information Center

The Ames Laboratory SDI system requires a minimum of human intervention. The adaptability of the system provides two major contributions to information dissemination. (1) The user benefits proportionately from the amount of effort he expends in setting up his profile and the diligence in sending back responses. (2) The document input has only to…

Sage, C. R.; Fitzwater, D. R.

13

Socratic Dialog-Inducing (SDI) Labs

NSDL National Science Digital Library

SDI Labs are "guided construction" labs featuring hands-and-heads-on experiments in introductory mechanics. Their effectiveness in promoting student crossover to the the Newtonian World has been demonstrated by rigorous pre-post testing. Seven labs and references are included.

Hake, Richard

2003-10-10

14

The origins of SDI, 1944--1983

The most distinctive and important contribution of this new book on the Strategic Defense Initiative is that it ends where most other studies begin, with President Ronald Reagan's famous (or infamous, depending on one's perspective) March 1983 speech that introduced the Star Wars concept. In taking this approach, Donald R. Baucom - a former Air Force historian who has been the official historian who has been the official historian of the Strategic Defense Initiative Organization since May 1987 - helps to correct the common misperception that US efforts in strategic defense began and ended with the SDI. Although Baucom tells us that The Origins of SDI is a significantly revised version of an SDIO study he completed in 1989, representing his own views and not those of the SDIO, the reader should be warned that the book reads like an official history. It is often dry or too episodic and offers little that is new in the way of analysis or interpretation.

Baucom, D.R.

1992-01-01

15

October 2011 SDI FEP Issues Heat Conduction Issues (HC)

October 2011 Â SDI FEP Issues Heat Conduction Issues (HC) SDI(HC) -1 DOE needs to provide of the run-of-mine salt would conduct less heat away from the heater than that analyzed here, and potentially temperature halite and run-of-mine salt would conduct less heat away from the heater and potentially produce

16

Surface drip irrigation (SDI): Status of the technology in 2010

Technology Transfer Automated Retrieval System (TEKTRAN)

Subsurface drip irrigation (SDI), although a much smaller fraction of the microirrigated land area than surface drip irrigation, is growing at a much faster rate and is the subject of considerable research and educational efforts in the United States. This paper will discuss the growth in SDI, highl...

17

Statistical-dynamical downscaling of wind climatologies

A statistical-dynamical downscaling procedure is applied for an investigation into the availability of wind power over a region of 80 × 87 km which covers flat and hilly terrain. The approach is based on the statistical coupling of a regionally representative wind climate with a numerical atmospheric mesoscale model. The large-scale wind climatology is calculated by a cluster-analysis of a

Heinz-Theo Mengelkamp; Hartmut Kapitza; Ulrich Pflüger

1997-01-01

18

1 of 3 DOE Response to EPA Question SDI(HCR)-1 on the SDI Planned Change Notice

no heat from the SDI heater test will be transported by convection to the lower portion of the exhaust transported heat from the SDI heater test to the lower portion of the WIPP exhaust shaft will also be minimal(HCR)-1: Please provide information on the expected effects of convectively transported heat from

19

Zeno Dynamics in Quantum Statistical Mechanics

We study the quantum Zeno effect in quantum statistical mechanics within the operator algebraic framework. We formulate a condition for the appearance of the effect in W*-dynamical systems, in terms of the short-time behaviour of the dynamics. Examples of quantum spin systems show that this condition can be effectively applied to quantum statistical mechanical models. Further, we derive an explicit form of the Zeno generator, and use it to construct Gibbs equilibrium states for the Zeno dynamics. As a concrete example, we consider the X-Y model, for which we show that a frequent measurement at a microscopic level, e.g. a single lattice site, can produce a macroscopic effect in changing the global equilibrium.

Andreas U. Schmidt

2002-07-11

20

Statistical Properties of the Cluster Dynamics of the Systems of Statistical Mechanics

Statistical Properties of the Cluster Dynamics of the Systems of Statistical Mechanics A. Gabrielov dynamics was shown to exist in the one-dimensional sys- tems of statistical mechanics in [S1]. Consider "dynamical" explanation of irreversibility. The StoÃ?anzahlsatz can be applied to any system of statistical

Gabrielov, Andrei

21

Teaching the principles of statistical dynamics.

We describe a simple framework for teaching the principles that underlie the dynamical laws of transport: Fick's law of diffusion, Fourier's law of heat flow, the Newtonian viscosity law, and the mass-action laws of chemical kinetics. In analogy with the way that the maximization of entropy over microstates leads to the Boltzmann distribution and predictions about equilibria, maximizing a quantity that E. T. Jaynes called "caliber" over all the possible microtrajectories leads to these dynamical laws. The principle of maximum caliber also leads to dynamical distribution functions that characterize the relative probabilities of different microtrajectories. A great source of recent interest in statistical dynamics has resulted from a new generation of single-particle and single-molecule experiments that make it possible to observe dynamics one trajectory at a time. PMID:23585693

Ghosh, Kingshuk; Dill, Ken A; Inamdar, Mandar M; Seitaridou, Effrosyni; Phillips, Rob

2006-02-01

22

Air Force Satellite Control Network and SDI development

NASA Astrophysics Data System (ADS)

The Air Force Satellite Control Network (AFSCN) represents a military, worldwide network of control centers and remote tracking sites (RTS). A relatively large and growing constellation of DOD satellites is supported. The near term and long term plans for the AFSCN are discussed, taking into account also the impact of the Space Defense Initiative (SDI) on the AFSCN. It is pointed out that the SDI adds a new dimension to the support provided by the AFSCN to the DOD satellites, because some SDI scenarios being considered include many more satellite platforms, each containing multiple kinetic energy weapons. Space-ground link sites are discussed along with AFSCN control sites, and communication between RTS and control centers. Attention is given to changing roles and responsibilities, the Satellite Test Center (STC) as an excellent site for the R and D phase of SDI development, and an operational concept for a highly proliferated weapons platforms architecture, and goals of developing more survivable satellite systems.

Bleier, T.

23

On quantum dynamics and statistics of vectors

NASA Astrophysics Data System (ADS)

Given a sequence of vectors in a Hilbert space, we propose to use the spectrum of the associated Gram matrix as a tool for extracting statistical information on the sequence. We examine two simple models in some detail: the fractional shift where the sequence is generated by a deterministic unitary dynamics and random normalized vectors in a high-dimensional space chosen at a given density. In both cases, the limiting eigenvalue distribution of the Gram matrix is explicitly found. We relate our results to the notion of growth entropy and recover in the stochastic case the eigenvalue distribution of the Wishart matrices.

DeCock, M.; Fannes, M.; Spincemaille, P.

1999-09-01

24

Teachers' Use of Transnumeration in Solving Statistical Tasks with Dynamic Statistical Software

ERIC Educational Resources Information Center

This study examined a random stratified sample (n = 62) of teachers' work across eight institutions on three tasks that utilized dynamic statistical software. We considered how teachers may utilize and develop their statistical knowledge and technological statistical knowledge when investigating a statistical task. We examined how teachers…

Lee, Hollylynne S.; Kersaint, Gladis; Harper, Suzanne R.; Driskell, Shannon O.; Jones, Dusty L.; Leatham, Keith R.; Angotti, Robin L.; Adu-Gyamfi, Kwaku

2014-01-01

25

Ames Selective Dissemination of Information (SDI) System Operating Manual.

ERIC Educational Resources Information Center

The Ames Selective Dissemination of Information (SDI) System is an attempt to efficiently place rapidly increasing amounts of information into the hands of scientists and engineers who can exploit it. It is a computerized current awareness system designed to increase researchers' literature searching capabilities by bringing to their attention…

Anderson, Lloyd E.; Wegner, Waldo W.

26

SDI Considerations for North Carolina Growers and Producers

Technology Transfer Automated Retrieval System (TEKTRAN)

Humid areas, such as the southeastern and midsouthern United States, have particular climate, topography, soils, cropping systems, and water sources that require special consideration when implementing a subsurface drip irrigation (SDI) system. These factors are normally different enough in value or...

27

Design and Installation of SDI Systems in North Carolina

Technology Transfer Automated Retrieval System (TEKTRAN)

As a part of the humid Southeast, North Carolina’s climate, topography, soils, cropping systems, and water sources require special consideration when considering and implementing a subsurface drip irrigation (SDI) system. This publication is not a step-by-step design manual, but it will help you in ...

28

Dynamic Statistical Graphics in the CAVE Virtual Reality Environment

Dynamic Statistical Graphics in the CAVE Virtual Reality Environment Jurgen Symanzik, Dianne Cook: symanzik@iastate.edu Abstract The CAVE is a high end immersive virtual reality environment that allows 3 Introduction This paper contains work related to dynamic statistical graphics DSG and the CAVE virtual reality

Symanzik, JÃ¼rgen

29

LDSG Workshop on Stochastic Dynamics and Nonequilibrium Statistical Mechanics

LDSG Workshop on Stochastic Dynamics and Nonequilibrium Statistical Mechanics Organisers: Rosemary the same predictive power as that of equilibrium statistical mechanics? Though most researchers in statistical mechanics would hope and conjecture that the answer is yes, we do not have at present

Wright, Francis

30

Statistical Mechanics of Recurrent Neural Networks II Dynamics

CHAPTER 15 Statistical Mechanics of Recurrent Neural Networks II Â± Dynamics A.C.C. COOLEN none- quilibrium statistical mechanical techniques, is the sequel of [1], which was devoted to solving networks and their properties. Equilibrium statistical mechanical techniques can provide much detailed quan

Coolen, ACC "Ton"

31

SMOOTH DYNAMICS AND NEW THEORETICAL IDEAS IN NONEQUILIBRIUM STATISTICAL MECHANICS.

SMOOTH DYNAMICS AND NEW THEORETICAL IDEAS IN NONEQUILIBRIUM STATISTICAL MECHANICS. by David Ruelle, and Gibbs, consists of two rather di#11;erent parts: equilibrium and nonequilibrium statistical mechanics. The success of equilibrium statistical mechanics has been spectacular. It has been developed to a high degree

Ruelle, David

32

SMOOTH DYNAMICS AND NEW THEORETICAL IDEAS IN NONEQUILIBRIUM STATISTICAL MECHANICS.

SMOOTH DYNAMICS AND NEW THEORETICAL IDEAS IN NONEQUILIBRIUM STATISTICAL MECHANICS. by David Ruelle, and Gibbs, consists of two rather different parts: equilibrium and nonequilibrium statistical mechanics. The success of equilibrium statistical mechanics has been spectacular. It has been developed to a high degree

33

Dynamic Statistics of Crayfish Caudal Photoreceptors

Crayfish caudal photoreceptor units were monitored during transient and steady-state responses to light stimuli (step on, step off). A statistical analysis of interpulse interval distributions during quasi-stationary time periods was carried out. Firing statistics during transient conditions were superposable with statistics under whatever steady stimulation produced the same firing rate, indicating that mean firing rate is a sufficient statistic. Distributions encountered formed a continuum of possible shapes. Considerable variation in shape was found with temperature and also among species, with Orconectes clarkii tending to fire more regularly than Orconectes virilis. Some properties of O. virilis statistics are described, including a linear relation between mean and standard deviation, and a tendency for intervals to be nonindependent. The data are considered as constraints on closed form models of the photoreceptor nerve pulse generator. PMID:6035125

Hermann, Howard T.; Olsen, Richard E.

1967-01-01

34

Dynamic statistics of crayfish caudal photoreceptors.

Crayfish caudal photoreceptor units were monitored during transient and steady-state responses to light stimuli (step on, step off). A statistical analysis of interpulse interval distributions during quasi-stationary time periods was carried out. Firing statistics during transient conditions were superposable with statistics under whatever steady stimulation produced the same firing rate, indicating that mean firing rate is a sufficient statistic. Distributions encountered formed a continuum of possible shapes. Considerable variation in shape was found with temperature and also among species, with Orconectes clarkii tending to fire more regularly than Orconectes virilis. Some properties of O. virilis statistics are described, including a linear relation between mean and standard deviation, and a tendency for intervals to be nonindependent. The data are considered as constraints on closed form models of the photoreceptor nerve pulse generator. PMID:6035125

Hermann, H T; Olsen, R E

1967-05-01

35

Soviet military on SDI (Strategic Defense Initiative). Professional paper

Numerous Western analysts have suggested that all American assessments of SDI should proceed not only from a consideration of American intentions, but also from the outlook of Soviet perceptions. Since 23 March 1983, the prevailing tone of Soviet military writings on SDI has been overwhelmingly negative. Myron Hedlin has concluded that this harsh reaction to a U.S. initiative still years from realization suggests both a strong concern about the ultimate impact of these plans on the strategic balance, and a perceived opportunity for scoring propaganda points. Indeed, the present review of Soviet writings since President Reagan's so-called Star Wars speech has yielded both objective Soviet concerns and regressions to psychological warfare. This, in turn, has necessitated a careful effort to separate rhetoric from more official assessments of SDI. While there has long been dispute in the West over the validity of Soviet statements, they have time and again been subsequently confirmed in Soviet hardware, exercises, and operational behavior. Some Western analysts will nonetheless contend that the Soviet statements under examination in this study are merely a commodity for export.

Fitzgerald, M.C.

1987-08-01

36

Dynamical Ensembles in Nonequilibrium Statistical Mechanics

Ruelle's principle for turbulence leading to what is usually called the Sinai-Ruelle-Bowen (SRB) distribution is applied to the statistical mechanics of many particle systems in nonequilibrium stationary states. A specific prediction, obtained without the need to construct explicitly the SRB itself, is shown to be in agreement with a recent computer experiment on a strongly sheared fluid. This presents the

G. Gallavotti; E. G. D. Cohen

1995-01-01

37

Dynamaps: Dynamic Queries on a Health Statistics Atlas

Dynamaps: Dynamic Queries on a Health Statistics Atlas Catherine Plaisant and Vinit Jain Human Computer Interaction Laboratory A.V. Williams Bldg. University of Maryland College Park MD 20742 1 (301, correlations, atlas, time trend, health. ABSTRACT Dynamic queries are userÂcontrolled animated displays

Golbeck, Jennifer

38

Segmenting Dynamic Human Action via Statistical Structure

ERIC Educational Resources Information Center

Human social, cognitive, and linguistic functioning depends on skills for rapidly processing action. Identifying distinct acts within the dynamic motion flow is one basic component of action processing; for example, skill at segmenting action is foundational to action categorization, verb learning, and comprehension of novel action sequences. Yet…

Baldwin, Dare; Andersson, Annika; Saffran, Jenny; Meyer, Meredith

2008-01-01

39

A dynamic statistical experiment for atmospheric interactions

Interactions among atmospheric parameters exist at different scales. The pristine approach for observational or model data analysis involves changing the input parameters one at a time (OAT) and studying the effect on the system. Limitations of this approach for atmospheric applications are discussed. A fractional factorial (FF) based study is evolved and a methodology is outlined involving dynamic graphical analysis.

Devdutta S. Niyogi; Sethu Raman; Kiran Alapaty; Jongil Han

1997-01-01

40

Due to its simplicity, silt density index (SDI) is extensively used in reverse osmosis systems despite its limitations in predicting membrane fouling. Employing a reliable fouling index with good reproducibility and precision is necessary. The aim of this investigation is to assess the reliability of SDI in order to understand the reasons for the low level of precision and accuracy.

R. M. Rachman; N. Ghaffour; F. Wali; G. L. Amy

2012-01-01

41

Microform Informing: Use of DIALOG SDI to Produce a Microfiche Announcement Bulletin.

ERIC Educational Resources Information Center

Describes use of selective dissemination of information (SDI) feature on DIALOG at Sandia Technical Library to produce bulletin announcing library acquisitions of technical reports in microfiche. Microfiche acquisition, developing profile, assembling profile output, costs, and suggestions for improvement are highlighted. Examples of SDI profiles…

Rowe, Gladys E.

1984-01-01

42

Statistical coarse-graining of molecular dynamics into peridynamics.

This paper describes an elegant statistical coarse-graining of molecular dynamics at finite temperature into peridynamics, a continuum theory. Peridynamics is an efficient alternative to molecular dynamics enabling dynamics at larger length and time scales. In direct analogy with molecular dynamics, peridynamics uses a nonlocal model of force and does not employ stress/strain relationships germane to classical continuum mechanics. In contrast with classical continuum mechanics, the peridynamic representation of a system of linear springs and masses is shown to have the same dispersion relation as the original spring-mass system.

Silling, Stewart Andrew; Lehoucq, Richard B.

2007-10-01

43

Dynamic laser speckle analysis via normal vector space statistics

NASA Astrophysics Data System (ADS)

Dynamic laser speckle analysis is a useful measurement technique which can be used to analyze micro-motion on a sample surface via temporal statistics based on a sequence of speckle images. The existing analysis methods in the literature are based on intensity variation of the speckle images over time. It is observed that the robustness of these methods can be significantly influenced by the presence of non-uniform incidence and reflectivity, and unrelated image intensity variations. Hence, their applicable circumstances are limited. In this paper, a novel method for dynamic speckle analysis is proposed to address the interference of non-uniform incidence and reflectivity, and unrelated intensity variations. The dynamics of the speckle pattern at a pixel is measured by the temporal statistics for the directions of local normal vectors (rather the intensities) on every speckle image over time. The proposed method can effectively eliminate the aforementioned impacts in a dynamic speckle analysis process. Moreover, the local normal vector at a particular pixel in a speckle image also carries local geometry information regarding to its neighboring pixels. Three algorithms for computing the statistics of the directions of local normal vectors over time are subsequently presented. The effectiveness of the proposed method is demonstrated via the analysis of dynamic speckle patterns measured from a paint drying experiment. The robustness of the proposed method is compared with that of the typical existing methods through processing the dynamic speckle of simulation experiments under non-uniform and varying lighting conditions.

Zhong, Xu; Wang, Xuezhi; Cooley, Nicola; Farrell, Peter; Moran, Bill

2013-09-01

44

Hydrological responses to dynamically and statistically downscaled climate model output

Daily rainfall and surface temperature series were simulated for the Animas River basin, Colorado using dynamically and statistically downscaled output from the National Center for Environmental Prediction\\/ National Center for Atmospheric Research (NCEP\\/NCAR) re-analysis. A distributed hydrological model was then applied to the downscaled data. Relative to raw NCEP output, downscaled climate variables provided more realistic simulations of basin scale

Robert L. Wilby; Lauren E. Hay; William J. Gutowski Jr.; Raymond W. Arritt; Eugene S. Takle; Zaitao Pan; George H. Leavesley; Martyn P. Clark

2000-01-01

45

Smooth dynamics and new theoretical ideas in nonequilibrium statistical mechanics

This paper reviews various applications of the theory of smooth dynamical systems to conceptual problems of nonequilibrium statistical mechanics. We adopt a new point of view which has emerged progressively in recent years, and which takes seriously into account the chaotic character of the microscopic time evolution. The emphasis is on nonequilibrium steady states rather than the traditional approach to

David Ruelle

1998-01-01

46

Multifragment decay of hot nuclei: Dynamics or statistics

Multifragment events are shown to be associated with specific sources characterized by their mass and excitation energy through the incomplete fusion model. Excitation functions for the different multifragment decay channels are found to be almost independent of the systems and the incident energy. Preliminary comparisons of the data with dynamical calculations followed by statistical decay calculations are discussed. 14 refs., 8 figs.

Moretto, L.; Roussel-Chomaz, P.; Blumenfeld, Y.; Charity, R.; Colonna, M.; Colonna, N.; Libby, B.; Hanold, K.; Peaslee, G.; Wozniak, G.J.

1991-06-01

47

Statistical dynamics of tropical wind in radiosonde data

NASA Astrophysics Data System (ADS)

Weibull distributions were fitted to wind speed data from radiosonde stations in the global tropics. A statistical theory of independent wind contributions was proposed to partially explain the shape parameter k obtained over Malay Peninsula and the wider Equatorial Monsoon Zone. This statistical dynamical underpinning provides some justification for using empirical Weibull fits to derive wind speed thresholds for monitoring data quality. The regionally adapted thresholds retain more useful data than conventional ones defined from taking the regional mean plus three standard deviations. The new approach is shown to eliminate reports of atypically strong wind over Malay Peninsula which may have escaped detection in quality control of global datasets as the latter has assumed a larger spread of wind speed. New scientific questions are raised in the pursuit of statistical dynamical understanding of meteorological variables in the tropics.

Koh, T.-Y.; Djamil, Y. S.; Teo, C.-K.

2011-05-01

48

Dynamical versus statistical mesoscopic models for DNA denaturation

We recently proposed a dynamical mesoscopic model for DNA, which is based, like statistical ones, on site-dependent finite stacking and pairing enthalpies. In the present article, we first describe how the parameters of this model are varied to get predictions in better agreement with experimental results that were not addressed up to now, like mechanical unzipping, the evolution of the critical temperature with sequence length, and temperature resolution. We show that the model with the new parameters provides results that are in quantitative agreement with those obtained from statistical models. Investigation of the critical properties of the dynamical model suggests that DNA denaturation looks like a first-order phase transition in a broad temperature interval, but that there necessarily exists, very close to the critical temperature, a crossover to another regime. The exact nature of the melting dynamics in this second regime still has to be elucidated. We finally point out that the descriptions of the ph...

Joyeux, Marc

2008-01-01

49

SDI and the lawyers: Evolving interpretations of international arms control accords

This note surveys international agreements that SDI may violate and discusses the policies underlying these potential legal and diplomatic conflicts. Part I provides an overview of the ABM Treaty, with emphasis on the provisions involved in the present interpretation controversy. Part II considers five other international covenants containing provisions upon which SDI may ultimately encroach. Part III evaluates several policy proposals that would permit SDI to proceed consistently with American international diplomatic commitments. This part also examines how an outright abrogation of the ABM Treaty or other agreements might affect American credibility and the arms-control process.

Kaman, E.J.; Loprest, F.J. Jr.; Pisano, N.A.; Steiner, R.W.

1989-01-01

50

Statistical computations underlying the dynamics of memory updating.

Psychophysical and neurophysiological studies have suggested that memory is not simply a carbon copy of our experience: Memories are modified or new memories are formed depending on the dynamic structure of our experience, and specifically, on how gradually or abruptly the world changes. We present a statistical theory of memory formation in a dynamic environment, based on a nonparametric generalization of the switching Kalman filter. We show that this theory can qualitatively account for several psychophysical and neural phenomena, and present results of a new visual memory experiment aimed at testing the theory directly. Our experimental findings suggest that humans can use temporal discontinuities in the structure of the environment to determine when to form new memory traces. The statistical perspective we offer provides a coherent account of the conditions under which new experience is integrated into an old memory versus forming a new memory, and shows that memory formation depends on inferences about the underlying structure of our experience. PMID:25375816

Gershman, Samuel J; Radulescu, Angela; Norman, Kenneth A; Niv, Yael

2014-11-01

51

Statistical dynamics of equatorial waves in tropical radiosonde wind data

NASA Astrophysics Data System (ADS)

Weibull distributions were fitted to wind speed data from radiosonde stations in the global tropics. A statistical theory of equatorial waves was proposed to explain the shape parameter k obtained over Malay Peninsula and the wider Equatorial Monsoon Zone. The theory uses the (-5/3)-power law in quasi-2-D turbulence, classical Boltzmann statistics and the Central Limit Theorem. It provides a statistical dynamical basis for using empirical Weibull fits to derive wind speed thresholds for monitoring data quality. The regionally adapted thresholds retain more useful data than conventional ones defined from taking the regional mean plus three standard deviations. The new approach is shown to eliminate reports of atypically strong wind over Malay Peninsula which may have escaped detection in quality control of global datasets as the latter has assumed a larger spread of wind speed.

Koh, T.-Y.; Djamil, Y. S.; Teo, C. K.

2010-07-01

52

A statistical-dynamical downscaling procedure for global climate simulations

A statistical-dynamical downscaling procedure for global climate simulations is described. The procedure is based on the assumption that any regional climate is associated with a specific frequency distribution of classified large-scale weather situations. The frequency distributions are derived from multi-year episodes of low resolution global climate simulations. Highly resolved regional distributions of wind and temperature are calculated with a regional

F. Frey-Buness; D. Heimann; R. Sausen

1995-01-01

53

Dynamics, stability, and statistics on lattices and networks

These lectures aim at surveying some dynamical models that have been widely explored in the recent scientific literature as case studies of complex dynamical evolution, emerging from the spatio-temporal organization of several coupled dynamical variables. The first message is that a suitable mathematical description of such models needs tools and concepts borrowed from the general theory of dynamical systems and from out-of-equilibrium statistical mechanics. The second message is that the overall scenario is definitely reacher than the standard problems in these fields. For instance, systems exhibiting complex unpredictable evolution do not necessarily exhibit deterministic chaotic behavior (i.e., Lyapunov chaos) as it happens for dynamical models made of a few degrees of freedom. In fact, a very large number of spatially organized dynamical variables may yield unpredictable evolution even in the absence of Lyapunov instability. Such a mechanism may emerge from the combination of spatial extension and nonlinearity. Moreover, spatial extension allows one to introduce naturally disorder, or heterogeneity of the interactions as important ingredients for complex evolution. It is worth to point out that the models discussed in these lectures share such features, despite they have been inspired by quite different physical and biological problems. Along these lectures we describe also some of the technical tools employed for the study of such models, e.g., Lyapunov stability analysis, unpredictability indicators for “stable chaos,” hydrodynamic description of transport in low spatial dimension, spectral decomposition of stochastic dynamics on directed networks, etc.

Livi, Roberto [Institut d' Etudes Avancées (IEA), Université de Cergy-Pontoise (France)

2014-07-15

54

Dynamics, stability, and statistics on lattices and networks

NASA Astrophysics Data System (ADS)

These lectures aim at surveying some dynamical models that have been widely explored in the recent scientific literature as case studies of complex dynamical evolution, emerging from the spatio-temporal organization of several coupled dynamical variables. The first message is that a suitable mathematical description of such models needs tools and concepts borrowed from the general theory of dynamical systems and from out-of-equilibrium statistical mechanics. The second message is that the overall scenario is definitely reacher than the standard problems in these fields. For instance, systems exhibiting complex unpredictable evolution do not necessarily exhibit deterministic chaotic behavior (i.e., Lyapunov chaos) as it happens for dynamical models made of a few degrees of freedom. In fact, a very large number of spatially organized dynamical variables may yield unpredictable evolution even in the absence of Lyapunov instability. Such a mechanism may emerge from the combination of spatial extension and nonlinearity. Moreover, spatial extension allows one to introduce naturally disorder, or heterogeneity of the interactions as important ingredients for complex evolution. It is worth to point out that the models discussed in these lectures share such features, despite they have been inspired by quite different physical and biological problems. Along these lectures we describe also some of the technical tools employed for the study of such models, e.g., Lyapunov stability analysis, unpredictability indicators for "stable chaos," hydrodynamic description of transport in low spatial dimension, spectral decomposition of stochastic dynamics on directed networks, etc.

Livi, Roberto

2014-07-01

55

A Stochastic Fractional Dynamics Model of Rainfall Statistics

NASA Astrophysics Data System (ADS)

Rainfall varies in space and time in a highly irregular manner and is described naturally in terms of a stochastic process. A characteristic feature of rainfall statistics is that they depend strongly on the space-time scales over which rain data are averaged. A spectral model of precipitation has been developed based on a stochastic differential equation of fractional order for the point rain rate, that allows a concise description of the second moment statistics of rain at any prescribed space-time averaging scale. The model is designed to faithfully reflect the scale dependence and is thus capable of providing a unified description of the statistics of both radar and rain gauge data. The underlying dynamical equation can be expressed in terms of space-time derivatives of fractional orders that are adjusted together with other model parameters to fit the data. The form of the resulting spectrum gives the model adequate flexibility to capture the subtle interplay between the spatial and temporal scales of variability of rain but strongly constrains the predicted statistical behavior as a function of the averaging length and times scales. The main restriction is the assumption that the statistics of the precipitation field is spatially homogeneous and isotropic and stationary in time. We test the model with radar and gauge data collected contemporaneously at the NASA TRMM ground validation sites located near Melbourne, Florida and in Kwajalein Atoll, Marshall Islands in the tropical Pacific. We estimate the parameters by tuning them to the second moment statistics of the radar data. The model predictions are then found to fit the second moment statistics of the gauge data reasonably well without any further adjustment. Some data sets containing periods of non-stationary behavior that involves occasional anomalously correlated rain events, present a challenge for the model.

Kundu, Prasun; Travis, James

2013-04-01

56

Radio frequency FELs may win role in SDI

NASA Astrophysics Data System (ADS)

RF-type free electron lasers (FEL) produce micropulse packets lasting about 20 picosec each, a different approach than the high power pulses of induction-type FELs. A tapered wiggler developed at Las Alamos increases the efficiency of extracting laser energy from the electron beam by matching the field strength to electron velocity, avoiding absorption of field energy by electrons which shed velocity in the wiggler. Efficiency is also enhanced by using the electrons that have passed through the wiggler to generate microwave energy for pumping the RF power that accelerates the electron beam. A peak efficiency of 20 percent is projected with the energy recovery technique. Gains have also been achieved with grazing incidence mirrors added to the cavity in front of the wiggler, which is powered by klystron tubes operating at 1.3 GHz. A new photoelectric injector is being tested to overcome beam quality degradation problems experienced with injection by an electron gun from a travelling wave tube. Finally, several goals of particle beam programs also being pursued for SDI applications are summarized.

1986-08-01

57

The Melick method of inlet flow dynamic distortion prediction by statistical means is outlined. A hypothetic vortex model is used as the basis for the mathematical formulations. The main variables are identified by matching the theoretical total pressure rms ratio with the measured total pressure rms ratio. Data comparisons, using the HiMAT inlet test data set, indicate satisfactory prediction of

W. G. Schweikhard; Y. S. Chen

1986-01-01

58

Pasta Nucleosynthesis: Molecular dynamics simulations of nuclear statistical equilibrium

Background: Exotic non-spherical nuclear pasta shapes are expected in nuclear matter at just below saturation density because of competition between short range nuclear attraction and long range Coulomb repulsion. Purpose: We explore the impact of nuclear pasta on nucleosynthesis, during neutron star mergers, as cold dense nuclear matter is ejected and decompressed. Methods: We perform classical molecular dynamics simulations with 51200 and 409600 nucleons, that are run on GPUs. We expand our simulation region to decompress systems from an initial density of 0.080 fm^{-3} down to 0.00125 fm^{-3}. We study proton fractions of Y_P=0.05, 0.10, 0.20, 0.30, and 0.40 at T =0.5, 0.75, and 1.0 MeV. We calculate the composition of the resulting systems using a cluster algorithm. Results: We find final compositions that are in good agreement with nuclear statistical equilibrium models for temperatures of 0.75 and 1 MeV. However, for proton fractions greater than Y_P=0.2 at a temperature of T = 0.5 MeV, the MD simulations produce non-equilibrium results with large rod-like nuclei. Conclusions: Our MD model is valid at higher densities than simple nuclear statistical equilibrium models and may help determine the initial temperatures and proton fractions of matter ejected in mergers.

M. E. Caplan; A. S. Schneider; C. J. Horowitz; D. K. Berry

2014-12-29

59

Statistical light-mode dynamics of multipulse passive mode locking

NASA Astrophysics Data System (ADS)

We study the multipulse formation in passive mode locking in the framework of the statistical light-mode dynamics theory. It is a many-body theory that treats the complex many-mode laser system by statistical mechanics. We give a detailed theory and experimental verification for the important case of multiple-pulse formation in the laser cavity. We follow and extend our former work on the subject. We give a detailed analysis with a rigorous calculation of the partition function, the free energy, and the order parameter in the coarse-graining method within the mean-field theory that is exact in the light-mode system. The outcome is a comprehensive picture of multipulse formation and annihilation, pulse after pulse, in an almost quantized manner, as the noise (“temperature”) or the light power is varied. We obtain the phase diagram of the system, showing a series of first-order phase transitions, each belonging to a different number of pulses. We also study the hysteresis behavior, typical for such thermodynamic systems. We elaborate on the role of the saturable absorber structure in determining the multipulse formation. The theoretical results are compared to experimental measurements that we obtained with mode-locked fiber lasers, and we find an excellent agreement.

Weill, Rafi; Vodonos, Boris; Gordon, Ariel; Gat, Omri; Fischer, Baruch

2007-09-01

60

A statistical model for interpreting computerized dynamic posturography data

NASA Technical Reports Server (NTRS)

Computerized dynamic posturography (CDP) is widely used for assessment of altered balance control. CDP trials are quantified using the equilibrium score (ES), which ranges from zero to 100, as a decreasing function of peak sway angle. The problem of how best to model and analyze ESs from a controlled study is considered. The ES often exhibits a skewed distribution in repeated trials, which can lead to incorrect inference when applying standard regression or analysis of variance models. Furthermore, CDP trials are terminated when a patient loses balance. In these situations, the ES is not observable, but is assigned the lowest possible score--zero. As a result, the response variable has a mixed discrete-continuous distribution, further compromising inference obtained by standard statistical methods. Here, we develop alternative methodology for analyzing ESs under a stochastic model extending the ES to a continuous latent random variable that always exists, but is unobserved in the event of a fall. Loss of balance occurs conditionally, with probability depending on the realized latent ES. After fitting the model by a form of quasi-maximum-likelihood, one may perform statistical inference to assess the effects of explanatory variables. An example is provided, using data from the NIH/NIA Baltimore Longitudinal Study on Aging.

Feiveson, Alan H.; Metter, E. Jeffrey; Paloski, William H.

2002-01-01

61

NASA Technical Reports Server (NTRS)

The Melick method of inlet flow dynamic distortion prediction by statistical means is outlined. A hypothetic vortex model is used as the basis for the mathematical formulations. The main variables are identified by matching the theoretical total pressure rms ratio with the measured total pressure rms ratio. Data comparisons, using the HiMAT inlet test data set, indicate satisfactory prediction of the dynamic peak distortion for cases with boundary layer control device vortex generators. A method for the dynamic probe selection was developed. Validity of the probe selection criteria is demonstrated by comparing the reduced-probe predictions with the 40-probe predictions. It is indicated that the the number of dynamic probes can be reduced to as few as two and still retain good accuracy.

Schweikhard, W. G.; Chen, Y. S.

1986-01-01

62

NASA Astrophysics Data System (ADS)

The field of study of complex systems considers that the dynamics of complex systems are founded on universal principles that may be used to describe a great variety of scientific and technological approaches of different types of natural, artificial, and social systems. Several authors have suggested that earthquake dynamics and the dynamics of economic (financial) systems can be analyzed within similar mathematical frameworks. We apply concepts of the nonextensive statistical physics, on time-series data of observable manifestations of the underlying complex processes ending up with these different extreme events, in order to support the suggestion that a dynamical analogy exists between a financial crisis (in the form of share or index price collapse) and a single earthquake. We also investigate the existence of such an analogy by means of scale-free statistics (the Gutenberg-Richter distribution of event sizes). We show that the populations of: (i) fracto-electromagnetic events rooted in the activation of a single fault, emerging prior to a significant earthquake, (ii) the trade volume events of different shares/economic indices, prior to a collapse, and (iii) the price fluctuation (considered as the difference of maximum minus minimum price within a day) events of different shares/economic indices, prior to a collapse, follow both the traditional Gutenberg-Richter law as well as a nonextensive model for earthquake dynamics, with similar parameter values. The obtained results imply the existence of a dynamic analogy between earthquakes and economic crises, which moreover follow the dynamics of seizures, magnetic storms and solar flares.

Potirakis, Stelios M.; Zitis, Pavlos I.; Eftaxias, Konstantinos

2013-07-01

63

COMPARISON OF SPRAY, LEPA, AND SDI FOR COTTON AND GRAIN SORGHUM IN THE TEXAS PANHANDLE

Technology Transfer Automated Retrieval System (TEKTRAN)

Crop responses to MESA (mid-elevation spray applicator), LESA (low-elevation spray applicator), LEPA (low energy precision applicator), and SDI (subsurface drip irrigation) were compared for full and deficit irrigation levels in the Texas Panhandle. Crops included three seasons of grain sorghum and...

64

Near-surface soil water and temperature for SDI, LEPA, and spray irrigation

Technology Transfer Automated Retrieval System (TEKTRAN)

Near-surface soil temperatures and volumetric soil water contents were compared for SDI, LEPA, and spray irrigation in a Pullman clay loam soil planted in cotton. Soil temperatures were measured by type-T thermocouples and volumetric water contents were measured by time domain reflectometry (TDR) in...

65

A multinational SDI-based system to facilitate disaster risk management in the Andean Community

, Ecuador, and Peru). SIAPAD was based on the concept of a thematic Spatial Data Infrastructure (SDI to the significant frequency of occurrence in this area of potentially disastrous natural phenom- ena (earthquakes, Colombia, Ecuador, and Peru, developed the Andean Strategy for Disaster Prevention and Relief as a legal

Molina, MartÃn

66

WEB CARTOGRAPHY IN A WORLD OF SERVICES, SDI'S AND WEB 2.0

WEB CARTOGRAPHY IN A WORLD OF SERVICES, SDI'S AND WEB 2.0 Barend KÃ¶bben Euro of cartography in a changing world: information disseminated in digital ways all about sharing, interoperability, web services, SDIs and the modern twoÂway Web 2.0 this has consequences on the design of (web)cartography

KÃ¶bben, Barend

67

Modeling Insurgent Dynamics Including Heterogeneity. A Statistical Physics Approach

NASA Astrophysics Data System (ADS)

Despite the myriad complexities inherent in human conflict, a common pattern has been identified across a wide range of modern insurgencies and terrorist campaigns involving the severity of individual events—namely an approximate power-law x - ? with exponent ??2.5. We recently proposed a simple toy model to explain this finding, built around the reported loose and transient nature of operational cells of insurgents or terrorists. Although it reproduces the 2.5 power-law, this toy model assumes every actor is identical. Here we generalize this toy model to incorporate individual heterogeneity while retaining the model's analytic solvability. In the case of kinship or team rules guiding the cell dynamics, we find that this 2.5 analytic result persists—however an interesting new phase transition emerges whereby this cell distribution undergoes a transition to a phase in which the individuals become isolated and hence all the cells have spontaneously disintegrated. Apart from extending our understanding of the empirical 2.5 result for insurgencies and terrorism, this work illustrates how other statistical physics models of human grouping might usefully be generalized in order to explore the effect of diverse human social, cultural or behavioral traits.

Johnson, Neil F.; Manrique, Pedro; Hui, Pak Ming

2013-05-01

68

Pasta Nucleosynthesis: Molecular dynamics simulations of nuclear statistical equilibrium

Background: Exotic non-spherical nuclear pasta shapes are expected in nuclear matter at just below saturation density because of competition between short range nuclear attraction and long range Coulomb repulsion. Purpose: We explore the impact of nuclear pasta on nucleosynthesis, during neutron star mergers, as cold dense nuclear matter is ejected and decompressed. Methods: We perform classical molecular dynamics simulations with 51200 and 409600 nucleons, that are run on GPUs. We expand our simulation region to decompress systems from an initial density of 0.080 fm^{-3} down to 0.00125 fm^{-3}. We study proton fractions of Y_P=0.05, 0.10, 0.20, 0.30, and 0.40 at T =0.5, 0.75, and 1.0 MeV. We calculate the composition of the resulting systems using a cluster algorithm. Results: We find final compositions that are in good agreement with nuclear statistical equilibrium models for temperatures of 0.75 and 1 MeV. However, for proton fractions greater than Y_P=0.2 at a temperature of T = 0.5 MeV, the MD simulatio...

Caplan, M E; Horowitz, C J; Berry, D K

2014-01-01

69

Statistical and dynamical properties of a dissipative kicked rotator

NASA Astrophysics Data System (ADS)

Some dynamical and statistical properties for a conservative as well as the dissipative problem of relativistic particles in a waveguide are considered. For the first time, two different types of dissipation namely: (i) due to viscosity and; (ii) due to inelastic collision (upon the kick) are considered individually and acting together. For the first case, and contrary to what is expected for the original Zaslavsky’s relativistic model, we show there is a critical parameter where a transition from local to global chaos occurs. On the other hand, after considering the introduction of dissipation also on the kick, the structure of the phase space changes in the sense that chaotic and periodic attractors appear. We study also the chaotic sea by using scaling arguments and we proposed an analytical argument to reinforce the validity of the scaling exponents obtained numerically. In principle such an approach can be extended to any two-dimensional map. Finally, based on the Lyapunov exponent, we show that the parameter space exhibits infinite families of self-similar shrimp-shape structures, corresponding to periodic attractors, embedded in a large region corresponding to chaotic attractors.

Oliveira, Diego F. M.; Leonel, Edson D.

2014-11-01

70

Statistical and dynamical downscaling of precipitation over Spain from DEMETER seasonal forecasts

Statistical and dynamical downscaling methods are tested and compared for downscaling seasonal precipitation forecasts over Spain from two DEMETER models: the European Centre for Medium-Range Weather Forecasts (ECMWF) and the UK Meteorological Office (UKMO). The statistical method considered is a particular implementation of the standard analogue technique, based on close neighbours of the predicted atmospheric geopotential and humidity fields. Dynamical

E. Díez; C. Primo; J. A. García-Moya; J. M. Gutiérrez; B. Orfila

2005-01-01

71

Dynamic Statistical Graphics in the C2 Virtual Reality Environment J. Symanzik D. Cook

Dynamic Statistical Graphics in the C2 Virtual Reality Environment J. Symanzik D. Cook Department immersive virtual reality environ- ment that allows 3 dimensional projections of higher di- mensional virtual reality environment. So far, most applications of dynamic statistical graphics have involved

Symanzik, JÃ¼rgen

72

This tutorial discusses what-if analysis and optimization of System Dynamics models. These problems are solved, using the statistical techniques of regression analysis and design of experiments (DOE). These issues are illustrated by applying the statistical techniques to a System Dynamics model for coal transportation, taken from Wolstenholme's book \\

Jack P. C. Kleijnen

1995-01-01

73

ERIC Educational Resources Information Center

This study examined a random stratified sample (n = 62) of prospective teachers' work across eight institutions on three tasks that utilized dynamic statistical software. The authors considered how teachers utilized their statistical knowledge and technological statistical knowledge to engage in cycles of investigation. This paper characterizes…

Lee, Hollylynne Stohl; Kersaint, Gladis; Harper, Suzanne; Driskell, Shannon O.; Leatham, Keith R.

2012-01-01

74

Intermittency and Statistics of Single Biomolecule Reaction Dynamics

The statistics of individual activated events in slowly fluctuating environments such as biomolecules exhibits intermittency where rare activation events mostly dominate and may not always obey Poisson's law. Intermittency maybe characterized by high order statistics of the population. We used a path integral method to study the statistics of the populations. It is found that at short times, high order

Jin Wang; Peter Wolynes

1998-01-01

75

Enriching Spatial Data Infrastructure (sdi) by User Generated Contents for Transportation

NASA Astrophysics Data System (ADS)

Spatial data is one of the most critical elements underpinning decision making for many disciplines. Accessing and sharing spatial data have always been a great struggle for researchers. Spatial data infrastructure (SDI) plays a key role in spatial data sharing by building a suitable platform for collaboration and cooperation among the different data producer organizations. In recent years, SDI vision has been moved toward a user-centric platform which has led to development of a new and enriched generation of SDI (third generation). This vision is to provide an environment where users can cooperate to handle spatial data in an effective and satisfactory way. User-centric SDI concentrates on users, their requirements and preferences while in the past, SDI initiatives were mainly concentrated on technological issues such as the data harmonization, standardized metadata models, standardized web services for data discovery, visualization and download. On the other hand, new technologies such as the GPS-equipped smart phones, navigation devices and Web 2.0 technologies have enabled citizens to actively participate in production and sharing of the spatial information. This has led to emergence of the new phenomenon called the Volunteered Geographic Information (VGI). VGI describes any type of content that has a geographic element which has been voluntarily collected. However, its distinctive element is the geographic information that can be collected and produced by citizens with different formal expertise and knowledge of the spatial or geographical concepts. Therefore, ordinary citizens can cooperate in providing massive sources of information that cannot be ignored. These can be considered as the valuable spatial information sources in SDI. These sources can be used for completing, improving and updating of the existing databases. Spatial information and technologies are an important part of the transportation systems. Planning, design and operation of the transportation systems requires the exchange of large volumes of spatial data and often close cooperation among the various organizations. However, there is no technical and organizational process to get a suitable data infrastructure to address diverse needs of the transportation. Hence, development of a common standards and a simple data exchange mechanism is strongly needed in the field of transportation for decision support. Since one of the main purposes of transportation projects is to improve the quality of services provided to users, it is necessary to involve the users themselves in the decision making processes. This should be done through a public participation and involvement in all stages of the transportation projects. In other words, using public knowledge and information as another source of information is very important to make better and more efficient decisions. Public participation in transportation projects can also help organizations to enhance their public supports; because the lack of public support can lead to failure of technically valid projects. However, due to complexity of the transportation tasks, lack of appropriate environment and methods for facilitation of the public participation, collection and analysis of the public information and opinions, public participation in this field has not been well considered so far. This paper reviews the previous researches based on the enriched SDI development and its movement toward the VGI by focusing on the public participation in transportation projects. To this end, methods and models that have been used in previous researches are studied and classified initially. Then, methods of the previous researchers on VGI and transportation are conceptualized in SDI. Finally, the suggested method for transportation projects is presented. Results indicate success of the new generation of SDI in integration with public participation for transportation projects.

Shakeri, M.; Alimohammadi, A.; Sadeghi-Niaraki, A.; Alesheikh, A. A.

2013-09-01

76

Examining rainfall and cholera dynamics in Haiti using statistical and dynamic modeling approaches.

Haiti has been in the midst of a cholera epidemic since October 2010. Rainfall is thought to be associated with cholera here, but this relationship has only begun to be quantitatively examined. In this paper, we quantitatively examine the link between rainfall and cholera in Haiti for several different settings (including urban, rural, and displaced person camps) and spatial scales, using a combination of statistical and dynamic models. Statistical analysis of the lagged relationship between rainfall and cholera incidence was conducted using case crossover analysis and distributed lag nonlinear models. Dynamic models consisted of compartmental differential equation models including direct (fast) and indirect (delayed) disease transmission, where indirect transmission was forced by empirical rainfall data. Data sources include cholera case and hospitalization time series from the Haitian Ministry of Public Health, the United Nations Water, Sanitation and Health Cluster, International Organization for Migration, and Hôpital Albert Schweitzer. Rainfall data was obtained from rain gauges from the U.S. Geological Survey and Haiti Regeneration Initiative, and remote sensing rainfall data from the National Aeronautics and Space Administration Tropical Rainfall Measuring Mission. A strong relationship between rainfall and cholera was found for all spatial scales and locations examined. Increased rainfall was significantly correlated with increased cholera incidence 4-7 days later. Forcing the dynamic models with rainfall data resulted in good fits to the cholera case data, and rainfall-based predictions from the dynamic models closely matched observed cholera cases. These models provide a tool for planning and managing the epidemic as it continues. PMID:24267876

Eisenberg, Marisa C; Kujbida, Gregory; Tuite, Ashleigh R; Fisman, David N; Tien, Joseph H

2013-12-01

77

and dynamical downscaling approaches R. Mehrotra, J. P. Evans, A. Sharma and B. Sivakumar ABSTRACT downscaling model based on semi-parametric conditional simulation and a dynamical downscaling approach downscaling and statistical downscaling. Dynamical downscaling uses a limited-area high-resolution model (a

Evans, Jason

78

A comparison of statistical and dynamical downscaling for surface temperature in North America

A comparison of statistical and dynamical downscaling for surface temperature in North America. We employed a multiple linear regression model and the MM5 dynamical model to downscale June, July significantly to the level of agreement with dynamical downscaling. We found that the two methods and all

79

and dynamical downscaling approaches R. Mehrotra, J. P. Evans, A. Sharma and B. Sivakumar ABSTRACT downscaling model based on semi-parametric conditional simulation and a dynamical downscaling approach into two groups: dyna- mical downscaling and statistical downscaling. Dynamical downscaling uses a limited

Evans, Jason

80

Functional ANOVA and Regional Climate Experiments: A Statistical Analysis of Dynamic Downscaling

Functional ANOVA and Regional Climate Experiments: A Statistical Analysis of Dynamic Downscaling for dynamic downscaling of global models. In this paper, we discuss an initial analysis of a subset dynamic downscaling methods and demonstrate that there are significant differences between the two models

Sain, Steve

81

Statistical Prediction and Molecular Dynamics Simulation Ben Cooke* and Scott C. Schmidleryz

Statistical Prediction and Molecular Dynamics Simulation Ben Cooke* and Scott C. Schmidleryz simulations of macromolecules. We emphasize the use of molecular dynamics simulations to calculate to replica exchange molecular dynamics simulations of a set of eight helical peptides under the AMBER

Schmidler, Scott

82

Journal of Statistical Physics, Vol. 82, Nos. 1/2, 1996 Molecular Dynamics Simulation of

Journal of Statistical Physics, Vol. 82, Nos. 1/2, 1996 Molecular Dynamics Simulation of Size of a full 3D molecular dynamics simulation of size segregation by shaking, the so-called "Brazil nuts'4 and Stefan Sokolowski 1'5 Received May 22, 1995 We report the first three-dimensional molecular dynamics

Gallas, Jason

83

Statistical Dynamics of the Royal Road Genetic Algorithm

Metastability is a common phenomenon. Many evolutionary processes, both natural and ar- ticial, alternate between periods of stasis and brief periods of rapid change in their behavior. In this paper an analytical model for the dynamics of a mutation-only genetic algorithm (GA) is introduced that identies a new and general mechanism causing metastability in evolutionary dynamics. The GA's population dynamics

Erik van Nimwegen; James P. Crutchelda; Melanie Mitchell

84

Statistical Dynamics of the Royal Road Genetic Algorithm

Metastability is a common phenomenon. Many evolutionary processes, both natural and artificial, alternate between periods of stasis and brief periods of rapid change in their behavior. In this paper an analytical model for the dynamics of a mutation-only genetic algorithm (GA) is introduced that identifies a new and general mechanism causing metastability in evolutionary dynamics. The GA's population dynamics is

Erik Van Nimwegen; James P. Crutchfield; Melanie Mitchell

1999-01-01

85

Activities in HPM effects phenomenology at LLNL under the DNA/SDI Lth-6 effort

During the fiscal years 1984-1986, DNA funded an effort at the Lawrence Livermore National Laboratory under the SDI/Lth-6 program to develop models and to study the phenomenology of HPM interaction with systems. The effort concentrated on the following areas: linear coupling/modeling; linear coupling/experiments; nonlinear coupling/modeling; component failure/modeling; component characterization; and electronic subsystem characterization. This report sumarizes these subject areas.

Cabayan, H.S.; King, R.J.

1988-01-01

86

Acta Cryst. (2001). A57, 231Â±239 Chukhovskii et al. Statistical dynamical direct methods. II 231 Britain Â± all rights reserved Statistical dynamical direct methods. II. The three- phase structure, conventional statistical direct methods will yield a reasonable approximation to the effective dynamical

Marks, Laurence D.

87

Using Dynamic Statistical Graphics in a Highly Immersive Virtual Reality Environment to Understand Ecology Division, Corvallis, OR 97333 Abstract This paper discusses the extent of virtual reality (spatial) data in a highly immersive virtual reality environment. We will discuss definitions

Cook, Di

88

Crude closure dynamics through large scale statistical theories Marcus J. Grote and Andrew J. Majda

Crude closure dynamics through large scale statistical theories Marcus J. Grote and Andrew J. Majda 10012-1185 Received 22 January 1997; accepted 9 July 1997 Crude closure algorithms based on equilibrium on equilibrium energy-enstrophy statistical theory, or two parameters, the energy and circulation, for crude

Majda, Andrew J.

89

Statistical Computations Underlying the Dynamics of Memory Updating

Psychophysical and neurophysiological studies have suggested that memory is not simply a carbon copy of our experience: Memories are modified or new memories are formed depending on the dynamic structure of our experience, ...

Gershman, Samuel J.

90

Statistics of transverse mode turn-on dynamics in VCSELs

The turn-on process of a multimode VCSEL is investigated from a statistical point of view. Special attention Is paid to quantities such as time jitter and bit error rate. The single-mode performance of VCSELs during current modulation is compared to that of edge-emitting lasers

J. Dellunde; M. C. Torrent; J. M. Sancho; K. A. Shore

1997-01-01

91

Dynamics and statistics of heavy particles in turbulent flows

We present the results of Direct Numerical Simulations (DNS) of turbulent flows seeded with millions of passive inertial particles. The maximum Taylor's Reynolds number is around 200. We consider particles much heavier than the carrier flow in the limit when the Stokes drag force dominates their dynamical evolution. We discuss both the transient and the stationary regimes. In the transient

M. Cencini; J. Bec; L. Biferale; G. Boffetta; A. Celani; A. S. Lanotte; S. Musacchio; F. Toschi

2006-01-01

92

An open-source wireless sensor stack: from Arduino to SDI-12 to Water One Flow

NASA Astrophysics Data System (ADS)

Implementing a large-scale streaming environmental sensor network has previously been limited by the high cost of the datalogging and data communication infrastructure. The Christina River Basin Critical Zone Observatory (CRB-CZO) is overcoming the obstacles to large near-real-time data collection networks by using Arduino, an open source electronics platform, in combination with XBee ZigBee wireless radio modules. These extremely low-cost and easy-to-use open source electronics are at the heart of the new DIY movement and have provided solutions to countless projects by over half a million users worldwide. However, their use in environmental sensing is in its infancy. At present a primary limitation to widespread deployment of open-source electronics for environmental sensing is the lack of a simple, open-source software stack to manage streaming data from heterogeneous sensor networks. Here we present a functioning prototype software stack that receives sensor data over a self-meshing ZigBee wireless network from over a hundred sensors, stores the data locally and serves it on demand as a CUAHSI Water One Flow (WOF) web service. We highlight a few new, innovative components, including: (1) a versatile open data logger design based the Arduino electronics platform and ZigBee radios; (2) a software library implementing SDI-12 communication protocol between any Arduino platform and SDI12-enabled sensors without the need for additional hardware (https://github.com/StroudCenter/Arduino-SDI-12); and (3) 'midStream', a light-weight set of Python code that receives streaming sensor data, appends it with metadata on the fly by querying a relational database structured on an early version of the Observations Data Model version 2.0 (ODM2), and uses the WOFpy library to serve the data as WaterML via SOAP and REST web services.

Hicks, S.; Damiano, S. G.; Smith, K. M.; Olexy, J.; Horsburgh, J. S.; Mayorga, E.; Aufdenkampe, A. K.

2013-12-01

93

A CATLINE SDI for the reference department: collection development and current awareness tool.

A method for using a CATLINE SDI (selected dissemination of information) as a current awareness and collection development tool for the health sciences reference department is described. This paper reports three years of experience with this service in an academic health sciences library. It emphasizes the exploitation of four data elements in the CATLINE file: the Abstracting and Indexing Tag (AI) Data Element; the Shelving Location (SL) Data Element; the MeSH Heading (MH) Data Element; the Subheading Qualifier (SH) Data Element. PMID:3329923

McKinin, E J

1987-01-01

94

NASA Astrophysics Data System (ADS)

The field of study of complex systems considers that the dynamics of complex systems are founded on universal principles that may be used to describe a great variety of scientific and technological approaches of different types of natural, artificial, and social systems. Several authors have suggested that earthquake dynamics and neurodynamics can be analyzed within similar mathematical frameworks. Recently, authors have shown that a dynamical analogy supported by scale-free statistics exists between seizures and earthquakes, analyzing populations of different seizures and earthquakes, respectively. The purpose of this paper is to suggest a shift in emphasis from the large to the small scale: our analyses focus on a single epileptic seizure generation and the activation of a single fault (earthquake) and not on the statistics of sequences of different seizures and earthquakes. We apply the concepts of the nonextensive statistical physics to support the suggestion that a dynamical analogy exists between the two different extreme events, seizures and earthquakes. We also investigate the existence of such an analogy by means of scale-free statistics (the Gutenberg-Richter distribution of event sizes and the distribution of the waiting time until the next event). The performed analysis confirms the existence of a dynamic analogy between earthquakes and seizures, which moreover follow the dynamics of magnetic storms and solar flares.

Eftaxias, Konstantinos; Minadakis, George; Potirakis, Stelios. M.; Balasis, Georgios

2013-02-01

95

Statistical mechanics of neocortical interactions - Dynamics of synaptic modification

NASA Technical Reports Server (NTRS)

A recent study has demonstrated that several scales of neocortical interactions can be consistently analyzed with the use of methods of modern nonlinear nonequilibrium statistical mechanics. The formation, stability, and interaction of spatial-temporal patterns of columnar firings are explicitly calculated, to test hypothesized mechanisms relating to information processing. In this context, most probable patterns of columnar firings are associated with chemical and electrical synaptic modifications. It is stressed that synaptic modifications and shifts in most-probable firing patterns are highly nonlinear and interactive sets of phenomena. A detailed scenario of information processing is calculated of columnar coding of external stimuli, short-term storage via hysteresis, and long-term storage via synaptic modification.

Ingber, L.

1983-01-01

96

Hydoxyurea induces senescence-like growth arrest in normal human fibroblasts. p21(WAF/CIP1/SDI1), a cyclin dependent kinase inhibitor, was found to be upregulated during this growth arrest. Levels of p21(WAF/CIP1/SDI1) protein and mRNA were increased nine-fold by hydroxyurea in these cells. In order to determine whether p21(WAF/CIP1/SDI1) mRNA is increased by hydroxyurea at the transcriptional level, human fibroblast cells were transfected with reporter constructs containing a p21(WAF/CIP1/SDI1) promoter fragment and then treated with hydroxyurea. The luciferase activities in the reporter-transfected fibroblast cells were not increased by hydroxyurea, indicating that p21(WAF/CIP1/SDI1) transcription was not elevated by hydroxyurea. The half-life of the p21(WAF/CIP1/SDI1) mRNA was increased by 2.5-fold but that of p21(WAF/CIP1/SDI1) protein was not. Our results suggest that increased mRNA stability is the major mechanism of p21(WAF/CIP1/SDI1) elevation in the hydroxyurea-induced growth arrest of human fibroblasts. PMID:16111738

Kim, Hyun-Seok; Yeo, Eui-ju; Park, Seong-Hoon; Park, Joo-In; Park, Sang-Chul; Shin, Jong-Yeon; Kim, Min-Ju; Oh, Soo-Jin; Won, Moo-Ho; Kang, Tae-Chun; Park, Jae-Bong; Kim, Jaebong; Kim, Jong-Il; Lee, Hyun-Yong; Lee, Jae-Yong

2005-12-01

97

The Statistical Mechanics of Dynamic Pathways to Self-Assembly.

This review describes some important physical characteristics of the pathways (i.e., dynamical processes) by which molecular, nanoscale, and micrometer-scale self-assembly occurs. We highlight the existence of features of self-assembly pathways that are common to a wide range of physical systems, even though those systems may differ with respect to their microscopic details. We summarize some existing theoretical descriptions of self-assembly pathways and highlight areas-notably, the description of self-assembly pathways that occur far from equilibrium-that are likely to become increasingly important. Expected final online publication date for the Annual Review of Physical Chemistry Volume 66 is March 31, 2015. Please see http://www.annualreviews.org/catalog/pubdates.aspx for revised estimates. PMID:25493714

Whitelam, Stephen; Jack, Robert L

2014-12-01

98

Human turnover dynamics during sleep: Statistical behavior and its modeling

NASA Astrophysics Data System (ADS)

Turnover is a typical intermittent body movement while asleep. Exploring its behavior may provide insights into the mechanisms and management of sleep. However, little is understood about the dynamic nature of turnover in healthy humans and how it can be modified in disease. Here we present a detailed analysis of turnover signals that are collected by accelerometry from healthy elderly subjects and age-matched patients with neurodegenerative disorders such as Parkinson's disease. In healthy subjects, the time intervals between consecutive turnover events exhibit a well-separated bimodal distribution with one mode at ?10 s and the other at ?100 s, whereas such bimodality tends to disappear in neurodegenerative patients. The discovery of bimodality and fine temporal structures (?10 s) is a contribution that is not revealed by conventional sleep recordings with less time resolution (?30 s). Moreover, we estimate the scaling exponent of the interval fluctuations, which also shows a clear difference between healthy subjects and patients. We incorporate these experimental results into a computational model of human decision making. A decision is to be made at each simulation step between two choices: to keep on sleeping or to make a turnover, the selection of which is determined dynamically by comparing a pair of random numbers assigned to each choice. This decision is weighted by a single parameter that reflects the depth of sleep. The resulting simulated behavior accurately replicates many aspects of observed turnover patterns, including the appearance or disappearance of bimodality and leads to several predictions, suggesting that the depth parameter may be useful as a quantitative measure for differentiating between normal and pathological sleep. These findings have significant clinical implications and may pave the way for the development of practical sleep assessment technologies.

Yoneyama, Mitsuru; Okuma, Yasuyuki; Utsumi, Hiroya; Terashi, Hiroo; Mitoma, Hiroshi

2014-03-01

99

SERVIR's Contributions and Benefits to Belize thru Spatial Data Infrastructure (SDI) Development

NASA Technical Reports Server (NTRS)

Dan Irwin, the SERVIR Project Manager is being honored with the privilege of delivering the opening remarks at Belize s second celebration of GIS Day, a weeklong event to be held at the University of Belize's campus in the nation s capital, Belmopan. The request has been extended by the GIS Day Planning Committee which operates under the auspices of Belize s Ministry of Natural Resources & the Environment, which is the focal ministry for SERVIR. In the 20-30 min. allotted for the opening remarks, the SERVIR Project Manager will expound on how SERVIR, operating under the auspices of NASA s Ecological Forecasting Program, contributes to spatial data infrastructure (SDI) development in Belize. NASA s contributions to the region - particularly work under the Mesoamerican Biological Corridor - will be highlighted. Continuing, the remarks will discuss SERVIR s role in Belize s steadily expanding SDI, particularly in the context of delivering integrated decision support products via web-based infrastructure. The remarks will close with a call to the parties assembled to work together in the application of Earth Observation Systems technologies for the benefit of Belizean society as a whole. NASA s strong presence in Belize s GIS Day celebrations will be highlighted as sustained goodwill of the American people - in partial fulfillment of goals set forth under the Global Earth Observation System of Systems (GEOSS).

Irwin, Daniel E.

2006-01-01

100

Predictions of climate change over Europe using statistical and dynamical downscaling techniques

Statistical and dynamical downscaling predictions of changes in surface temperature and precipitation for 2080-2100, relative to pre-industrial conditions, are compared at 976 European observing sites, for January and July. Two dynamical downscaling methods are considered, involving the use of surface temperature or precipitation simulated at the nearest grid point in a coupled ocean-atmosphere general circulation model (GCM) of resolution 300

James Murphy

2000-01-01

101

Title: Towards the Construction of Statistical Cumulus Dynamics: Workshop on Concepts mechanics of a microphysical system provides the ultimate basis for its macrophysical thermodynamics with a review of plumes: their specification, dynamics and interactions. Also in traditional parameterizations

Plant, Robert

102

Novel dynamic measures of emetic behavior in musk shrews.

The emetic reflex occurs as a pattern of motor responses produced by a network of neurons in the hindbrain. Despite an understanding of the sequence of motor outputs that form an emetic episode (EE), the variability in the dynamics of multiple EEs across time remains a mystery. Many clinical investigations rely on once a day patient recall of total amount of vomiting, and preclinical studies frequently report only the total number of EE per unit time. The aim of the current study was to develop novel temporal measures of emetic activation in a preclinical model. Male and female musk shrews were tested with prototypical emetic stimuli: motion exposure (1 Hz), nicotine (5 mg/kg, sc), and copper sulfate (120 mg/kg, ig). New emetic measures included duration (time from first to last episode), rate, standard deviation of the inter-episode interval (SD-I), and a survival analysis of emetic latency (analyzed with Cox regression). Behavioral patterns associated with emesis were also assessed using statistical temporal pattern (T-pattern) analysis to measure nausea-like behaviors (e.g., immobility). The emetic stimuli produced different levels of total EE number, duration, rate, and SD-I. A typical antiemetic, the neurokinin 1 receptor antagonist CP-99,994, suppressed the number of EEs but was less effective for reducing the duration or prolonging the emetic latency. Overall, the current study shows the use of novel dynamic behavioral measures to more comprehensively assess emesis and the impact of therapies. PMID:23953843

Horn, Charles C; Wang, Hong; Estival, Laureline; Meyers, Kelly; Magnusson, Magnus S

2013-12-01

103

An Evaluation of Statistical and Dynamical Techniques for Downscaling Local Climate

An assessment is made of downscaling estimates of screen temperature and precipitation observed at 976 European stations during 1983-94. A statistical downscaling technique, in which local values are inferred from observed atmospheric predictor variables, is compared against two dynamical downscaling techniques, based on the use of the screen temperature or precipitation simulated at the nearest grid point in integrations of

James Murphy

1999-01-01

104

Virtual reality and dynamic statistical graphics: A bidirectional link in a heterogeneous and real-time navigation are provided by typical virtual reality systems. Database function- ality must interact properly with the virtual reality/database system. This is easier said than done

Symanzik, JÃ¼rgen

105

We show that in stellar core plasmas, the one-body momentum distribution function is strongly dependent, at least in the high velocity regime, on the microscopic dynamics of ion elastic collisions and therefore on the effective collisional cross sections if a random force field is present. We take into account two cross sections describing ion-dipole and ion-ion screened interactions. Furthermore, we introduce a third unusual cross section to link statistical distributions and a quantum effect originated by the energy-momentum uncertainty owing to many-body collisions. We also propose a possible physical interpretation in terms of a tidal-like force. We show that each collisional cross section gives rise to a slight peculiar correction on the Maxwellian momentum distribution function in a well defined velocity interval. We also find a possible link between microscopic dynamics of ions and statistical mechanics in interpreting our results in the framework of nonextensive statistical mechanics.

Ferro, F. [Dipartimento di Fisica, Politecnico di Torino, I-10129 Torino (Italy); INFN-Sezione di Torino, I-10125 Torino (Italy); Quarati, P. [Dipartimento di Fisica, Politecnico di Torino, I-10129 Torino (Italy); INFN-Sezione di Cagliari, I-09042 Monserrato (Italy)

2005-02-01

106

research papers 458 Hu et al. Statistical dynamical direct methods. I Acta Cryst. (2000). A56, 458 reserved Statistical dynamical direct methods. I. The effective kinematical approximation J. J. Hu, F. N diffraction, substantial success has been achieved over the last few years in applying it via direct methods

Marks, Laurence D.

107

Identification of the active region of the DNA synthesis inhibitory gene p21Sdi1/CIP1/WAF1.

The cloning of the negative growth regulatory gene, p21Sdi1, has led to the convergence of the fields of cellular senescence, cell cycle regulation and tumor suppression. This gene was first cloned as an inhibitor of DNA synthesis that was overexpressed in terminally non-dividing senescent human fibroblasts (SD11) and later as a p53 transactivated gene (WAF1) and a Cdk-interacting protein (CIP1, p21) that inhibited cyclin-dependent kinase activity. To identify the active region(s) of p21Sdi1, cDNA constructs encoding various deleted forms of the protein were analyzed. Amino acids 22-71 were found to be the minimal region required for DNA synthesis inhibition. Amino acids 49-71 were involved in binding to Cdk2, and constructs deleted in this region expressed proteins that were unable to inhibit Cdk2 kinase activity in vitro. The latter stretch of amino acids shared sequence similarity with amino acids 60-76 of the p27Kip1 protein, another Cdk inhibitor. Point mutations made in p21Sdi1 in this region confirmed that amino acids common to both proteins were involved in DNA synthesis inhibition. Additionally, a chimeric protein, in which amino acids 49-65 of p21Sdi1 were substituted with amino acids 60-76 of p27Kip1, had almost the same DNA synthesis inhibitory activity as the wild-type protein. The results indicate that the region of sequence similarity between p21Sdi1 and p27Kip1 encodes an inhibitory motif characteristic of this family of Cdk inhibitors. Images PMID:7859744

Nakanishi, M; Robetorye, R S; Adami, G R; Pereira-Smith, O M; Smith, J R

1995-01-01

108

A 'near-optimum' multiple path routing algorithm for space-based SDI networks

NASA Astrophysics Data System (ADS)

An adaptive routing algorithm for a midcourse, space-based SDI (Strategic Defense Initiative) architecture is presented. The goals include rapid recovery from both predictable and unpredictable outages as well as load balancing. Robust operation is critical. The routing table update algorithm is distributed, and it produces loop-free routes from periodic topology update information. In addition, multiple routes are found from source to destination nodes. This allows load splitting among these routes to achieve more effective load balancing. A heuristic is used to distribute the load among these routes. The basic algorithm also provides a mechanism to provide path diversity for added survivability. Recovery from failures detected locally occurs immediately through the use of alternate routes and an event-driven failure recovery algorithm. Simulation results are presented to demonstrate the algorithm behavior.

Cain, J. Bibb; Adams, Stanley L.; Noakes, Michael D.; Kryst, Tom; Althouse, Edwin L.

109

Hydoxyurea induces senescence-like growth arrest in normal human fibroblasts. p21WAF\\/CIP1\\/SDI1, a cyclin dependent kinase inhibitor, was found to be upregulated during this growth arrest. Levels of p21WAF\\/CIP1\\/SDI1 protein and mRNA were increased nine-fold by hydroxyurea in these cells. In order to determine whether p21WAF\\/CIP1\\/SDI1 mRNA is increased by hydroxyurea at the transcriptional level, human fibroblast cells were transfected with reporter

Hyun-Seok Kim; Eui-ju Yeo; Seong-Hoon Park; Joo-In Park; Sang-Chul Park; Jong-Yeon Shin; Min-Ju Kim; Soo-Jin Oh; Moo-Ho Won; Tae-Chun Kang; Jae-Bong Park; Jaebong Kim; Jong-Il Kim; Hyun-Yong Lee; Jae-Yong Lee

2005-01-01

110

Modified statistical dynamical diffraction theory: analysis of model SiGe heterostructures

A modified version of the statistical dynamical diffraction theory (mSDDT) permits full-pattern fitting of high-resolution X-ray diffraction scans from thin-film systems across the entire range from fully dynamic to fully kinematic scattering. The mSDDT analysis has been applied to a set of model SiGe/Si thin-film samples in order to define the capabilities of this approach. For defect-free materials that diffract at the dynamic limit, mSDDT analyses return structural information that is consistent with commercial dynamical diffraction simulation software. As defect levels increase and the diffraction characteristics shift towards the kinematic limit, the mSDDT provides new insights into the structural characteristics of these materials. PMID:24046498

Shreeman, P. K.; Dunn, K. A.; Novak, S. W.; Matyi, R. J.

2013-01-01

111

NASA Astrophysics Data System (ADS)

We analyze the intermittent Brownian dynamics (a succession of adsorption and bulk relocation steps) of a test particle over a single strand. We propose an analytic expression of the relocation time distribution at all times. We show that this distribution has a nontrivial heavily tailed statistics at long time with a diverging average relocation time. In order to experimentally probe this first passage statistics, we follow the intermittent Brownian dynamics of water molecules over long and stiff imogolite mineral strands, using a field cycling NMR dispersion technique. Our analytic derivation is found to be in good agreement with experimental data on a large domain of observation. Implications for the efficiency of a search strategy on a single filament are then discussed and the importance of the confinement and/or the finite size effect is emphasized.

Levitz, P.; Zinsmeister, M.; Davidson, P.; Constantin, D.; Poncelet, O.

2008-09-01

112

We analyze the intermittent Brownian dynamics (a succession of adsorption and bulk relocation steps) of a test particle over a single strand. We propose an analytic expression of the relocation time distribution at all times. We show that this distribution has a nontrivial heavily tailed statistics at long time with a diverging average relocation time. In order to experimentally probe this first passage statistics, we follow the intermittent Brownian dynamics of water molecules over long and stiff imogolite mineral strands, using a field cycling NMR dispersion technique. Our analytic derivation is found to be in good agreement with experimental data on a large domain of observation. Implications for the efficiency of a search strategy on a single filament are then discussed and the importance of the confinement and/or the finite size effect is emphasized. PMID:18850982

Levitz, P; Zinsmeister, M; Davidson, P; Constantin, D; Poncelet, O

2008-09-01

113

Coarsely resolved surface air temperature (2 m height) seasonal integrations from the Florida State University\\/Center for Ocean-Atmospheric Prediction Studies Global Spectral Model (FSU\\/COAPS GSM) (~1.8° lon.-lat. (T63)) for the period of 1994 to 2002 (March through September each year) are downscaled to a fine spatial scale of ~20 km. Dynamical and statistical downscaling methods are applied for the southeastern United

Young-Kwon Lim; D. W. Shin; Steven Cocke; T. E. LaRow; Justin T. Schoof; James J. O'Brien; Eric P. Chassignet

2007-01-01

114

Coarsely resolved surface air temperature (2 m height) seasonal integrations from the Florida State University\\/Center for Ocean-Atmospheric Prediction Studies Global Spectral Model (FSU\\/COAPS GSM) (?1.8° lon.-lat. (T63)) for the period of 1994 to 2002 (March through September each year) are downscaled to a fine spatial scale of ?20 km. Dynamical and statistical downscaling methods are applied for the southeastern United

Young-Kwon Lim; D. W. Shin; Steven Cocke; T. E. LaRow; Justin T. Schoof; James J. O'Brien; Eric P. Chassignet

2007-01-01

115

NASA Astrophysics Data System (ADS)

The estimation of possible impacts related to climate change on the wave climate is subject to several levels of uncertainty. In this work, we focus on the uncertainties inherent in the method applied to project the wave climate using atmospheric simulations. Two approaches are commonly used to obtain the regional wave climate: dynamical and statistical downscaling from atmospheric data. We apply both approaches based on the outputs of a global climate model (GCM), ARPEGE-CLIMAT, under three possible future scenarios (B1, A1B and A2) of the Fourth Assessment Report, AR4 (IPCC, 2007), along the French coast and evaluate their results for the wave climate with a high level of precision. The performance of the dynamical and the statistical methods is determined through a comparative analysis of the estimated means, standard deviations and monthly quantile distributions of significant wave heights, the joint probability distributions of wave parameters and seasonal and interannual variability. Analysis of the results shows that the statistical projections are able to reproduce the wave climatology as well as the dynamical projections, with some deficiencies being observed in the summer and for the upper tail of the significant wave height. In addition, with its low computational time requirements, the statistical downscaling method allows an ensemble of simulations to be calculated faster than the dynamical method. It then becomes possible to quantify the uncertainties associated with the choice of the GCM or the socio-economic scenarios, which will improve estimates of the impact of wave climate change along the French coast.

Laugel, Amélie; Menendez, Melisa; Benoit, Michel; Mattarolo, Giovanni; Méndez, Fernando

2014-12-01

116

The Melick method of inlet flow dynamic distortion prediction by statistical means is outlined. A hypothetic vortex model is used as the basis for the mathematical formulations. The main variables are identified by matching the theoretical total pressure rms ratio with the measured total pressure rms ratio. Data comparisons, using the HiMAT inlet test data set, indicate satisfactory prediction of

W. G. Schweikhard; Y. S. Chen

1986-01-01

117

NASA Astrophysics Data System (ADS)

Relaxation phenomena in a model (H2O)20 cluster are investigated by considering energy fluctuations and dielectric relaxation, making connections with the underlying hydrogen-bond rearrangement dynamics. In particular, we relate these effects to the potential energy surface, including rearrangement mechanisms, minimum energy pathways and normal mode excitations. The statistical behavior of structural transitions in this water cluster is also examined. The transition rates estimated from RRKM theory are compared with those obtained by molecular dynamics (MD) simulations. The RRKM rates are 1-3 orders of magnitude larger than the MD values and the difference is larger at low energy. To find the origin of this discrepancy, the mechanism of coupling among various modes is examined. We find that there is significant coupling only among a subset of the normal modes in the low energy dynamics. A modified statistical theory, assuming that only a subset of modes contributes to the reaction rate, reproduces the energy dependence of the MD transition rates quite well. It is also found that the energy fluctuations and dielectric relaxation are non-Debye in character, and instead exhibit so-called 1/f spectra.

Baba, Akinori; Hirata, Yoshihiro; Saito, Shinji; Ohmine, Iwao; Wales, David J.

1997-02-01

118

Alternative to the Well-known Statistical Dynamics of Linear Systems

The problem of determining the mathematical model of the dynamics of multi-dimensional control systems in the presence of noise under the condition that the correlation functions cannot be found. Known statistical dynamics of linear systems is a more effective alternative. Background information is presented in the form of individual implementations nonergodic stochastic processes. Such a realization is deterministic functions. We introduce the concept of systems of sets of signals for the components on the semiring. For the system of sets of linearly dependent and linearly independent of the measured signals of a certain frequency properties. Frequency method is designed to deal with the noise on the set of deterministic functions. Example is the determination of the dynamic characteristics of the aircraft in accordance with the data obtained in one automatic landing.

V. N. Tibabishev

2013-01-22

119

NASA Astrophysics Data System (ADS)

We present a detailed study of the statistical properties of the Agent Based Model introduced in paper I [Eur. Phys. J. B, DOI: 10.1140/epjb/e2009-00028-4] and of its generalization to the multiplicative dynamics. The aim of the model is to consider the minimal elements for the understanding of the origin of the stylized facts and their self-organization. The key elements are fundamentalist agents, chartist agents, herding dynamics and price behavior. The first two elements correspond to the competition between stability and instability tendencies in the market. The herding behavior governs the possibility of the agents to change strategy and it is a crucial element of this class of models. We consider a linear approximation for the price dynamics which permits a simple interpretation of the model dynamics and, for many properties, it is possible to derive analytical results. The generalized non linear dynamics results to be extremely more sensible to the parameter space and much more difficult to analyze and control. The main results for the nature and self-organization of the stylized facts are, however, very similar in the two cases. The main peculiarity of the non linear dynamics is an enhancement of the fluctuations and a more marked evidence of the stylized facts. We will also discuss some modifications of the model to introduce more realistic elements with respect to the real markets.

Alfi, V.; Cristelli, M.; Pietronero, L.; Zaccaria, A.

2009-02-01

120

All salmonid species investigated to date have been characterized with a male heterogametic sex-determination system. However, as these species do not share any Y-chromosome conserved synteny, there remains a debate on whether they share a common master sex-determining gene. In this study, we investigated the extent of conservation and evolution of the rainbow trout (Oncorhynchus mykiss) master sex-determining gene, sdY (sexually dimorphic on the Y-chromosome), in 15 different species of salmonids. We found that the sdY sequence is highly conserved in all salmonids and that sdY is a male-specific Y-chromosome gene in the majority of these species. These findings demonstrate that most salmonids share a conserved sex-determining locus and also strongly suggest that sdY may be this conserved master sex-determining gene. However, in two whitefish species (subfamily Coregoninae), sdY was found both in males and females, suggesting that alternative sex-determination systems may have also evolved in this family. Based on the wide conservation of sdY as a male-specific Y-chromosome gene, efficient and easy molecular sexing techniques can now be developed that will be of great interest for studying these economically and environmentally important species. PMID:23745140

Yano, Ayaka; Nicol, Barbara; Jouanno, Elodie; Quillet, Edwige; Fostier, Alexis; Guyomard, René; Guiguen, Yann

2013-01-01

121

OneGeology Web Services and Portal as a global geological SDI - latest standards and technology

NASA Astrophysics Data System (ADS)

The global coverage of OneGeology Web Services (www.onegeology.org and portal.onegeology.org) achieved since 2007 from the 120 participating geological surveys will be reviewed and issues arising discussed. Recent enhancements to the OneGeology Web Services capabilities will be covered including new up to 5 star service accreditation scheme utilising the ISO/OGC Web Mapping Service standard version 1.3, core ISO 19115 metadata additions and Version 2.0 Web Feature Services (WFS) serving the new IUGS-CGI GeoSciML V3.2 geological web data exchange language standard (http://www.geosciml.org/) with its associated 30+ IUGS-CGI available vocabularies (http://resource.geosciml.org/ and http://srvgeosciml.brgm.fr/eXist2010/brgm/client.html). Use of the CGI simpelithology and timescale dictionaries now allow those who wish to do so to offer data harmonisation to query their GeoSciML 3.2 based Web Feature Services and their GeoSciML_Portrayal V2.0.1 (http://www.geosciml.org/) Web Map Services in the OneGeology portal (http://portal.onegeology.org). Contributing to OneGeology involves offering to serve ideally 1:1000,000 scale geological data (in practice any scale now is warmly welcomed) as an OGC (Open Geospatial Consortium) standard based WMS (Web Mapping Service) service from an available WWW server. This may either be hosted within the Geological Survey or a neighbouring, regional or elsewhere institution that offers to serve that data for them i.e. offers to help technically by providing the web serving IT infrastructure as a 'buddy'. OneGeology is a standards focussed Spatial Data Infrastructure (SDI) and works to ensure that these standards work together and it is now possible for European Geological Surveys to register their INSPIRE web services within the OneGeology SDI (e.g. see http://www.geosciml.org/geosciml/3.2/documentation/cookbook/INSPIRE_GeoSciML_Cookbook%20_1.0.pdf). The Onegeology portal (http://portal.onegeology.org) is the first port of call for anyone wishing to discover the availability of global geological web services and has new functionality to view and use such services including multiple projection support. KEYWORDS : OneGeology; GeoSciML V 3.2; Data exchange; Portal; INSPIRE; Standards; OGC; Interoperability; GeoScience information; WMS; WFS; Cookbook.

Duffy, Tim; Tellez-Arenas, Agnes

2014-05-01

122

Rural areas represent approximately 95% of the 14000 km(2) Alabama Black Belt, an area of widespread Vertisols dominated by clayey, smectitic, shrink-swell soils. These soils are unsuitable for conventional onsite wastewater treatment systems (OWTS) which are nevertheless widely used in this region. In order to provide an alternative wastewater dosing system, an experimental field moisture controlled subsurface drip irrigation (SDI) system was designed and installed as a field trial. The experimental system that integrates a seasonal cropping system was evaluated for two years on a 500-m(2) Houston clay site in west central Alabama from August 2006 to June 2008. The SDI system was designed to start hydraulic dosing only when field moisture was below field capacity. Hydraulic dosing rates fluctuated as expected with higher dosing rates during warm seasons with near zero or zero dosing rates during cold seasons. Lower hydraulic dosing in winter creates the need for at least a two-month waste storage structure which is an insurmountable challenge for rural homeowners. An estimated 30% of dosed water percolated below 45-cm depth during the first summer which included a 30-year historic drought. This massive volume of percolation was presumably the result of preferential flow stimulated by dry weather clay soil cracking. Although water percolation is necessary for OWTS, this massive water percolation loss indicated that this experimental system is not able to effective control soil moisture within its monitoring zone as designed. Overall findings of this study indicated that soil moisture controlled SDI wastewater dosing is not suitable as a standalone system in these Vertisols. However, the experimental soil moisture control system functioned as designed, demonstrating that soil moisture controlled SDI wastewater dosing may find application as a supplement to other wastewater disposal methods that can function during cold seasons. PMID:21621905

He, Jiajie; Dougherty, Mark; Shaw, Joey; Fulton, John; Arriaga, Francisco

2011-10-01

123

Displaying R spatial statistics on Google dynamic maps with web applications created by Rwui

Background The R project includes a large variety of packages designed for spatial statistics. Google dynamic maps provide web based access to global maps and satellite imagery. We describe a method for displaying directly the spatial output from an R script on to a Google dynamic map. Methods This is achieved by creating a Java based web application which runs the R script and then displays the results on the dynamic map. In order to make this method easy to implement by those unfamiliar with programming Java based web applications, we have added the method to the options available in the R Web User Interface (Rwui) application. Rwui is an established web application for creating web applications for running R scripts. A feature of Rwui is that all the code for the web application being created is generated automatically so that someone with no knowledge of web programming can make a fully functional web application for running an R script in a matter of minutes. Results Rwui can now be used to create web applications that will display the results from an R script on a Google dynamic map. Results may be displayed as discrete markers and/or as continuous overlays. In addition, users of the web application may select regions of interest on the dynamic map with mouse clicks and the coordinates of the region of interest will automatically be made available for use by the R script. Conclusions This method of displaying R output on dynamic maps is designed to be of use in a number of areas. Firstly it allows statisticians, working in R and developing methods in spatial statistics, to easily visualise the results of applying their methods to real world data. Secondly, it allows researchers who are using R to study health geographics data, to display their results directly onto dynamic maps. Thirdly, by creating a web application for running an R script, a statistician can enable users entirely unfamiliar with R to run R coded statistical analyses of health geographics data. Fourthly, we envisage an educational role for such applications. PMID:22998945

2012-01-01

124

Background For organisms living or interacting in groups, the decision-making processes of an individual may be based upon aspects of both its own state and the states of other organisms around it. Much research has sought to determine how group decisions are made, and whether some individuals are more likely to influence these decisions than others. State-dependent modelling techniques are a powerful tool for exploring group decision-making processes, but analyses conducted so far have lacked methods for identifying how dependent an individual's actions are on the rest of the group. Results Here, we introduce and evaluate two easy-to-calculate statistics that quantify how dependent an individual's actions are upon the state of a co-player in a two-player state-dependent dynamic game. We discuss the merits of these statistics, and situations in which they would be useful. Conclusion Our statistical measures provide a means of quantifying how independent an individual's actions are. They also allow researchers to quantify the output of state-dependent dynamic games, and quantitatively assess the predictions of these models. PMID:17038165

Rands, Sean A; Johnstone, Rufus A

2006-01-01

125

Heterogeneous Structure of Stem Cells Dynamics: Statistical Models and Quantitative Predictions

NASA Astrophysics Data System (ADS)

Understanding stem cell (SC) population dynamics is essential for developing models that can be used in basic science and medicine, to aid in predicting cells fate. These models can be used as tools e.g. in studying patho-physiological events at the cellular and tissue level, predicting (mal)functions along the developmental course, and personalized regenerative medicine. Using time-lapsed imaging and statistical tools, we show that the dynamics of SC populations involve a heterogeneous structure consisting of multiple sub-population behaviors. Using non-Gaussian statistical approaches, we identify the co-existence of fast and slow dividing subpopulations, and quiescent cells, in stem cells from three species. The mathematical analysis also shows that, instead of developing independently, SCs exhibit a time-dependent fractal behavior as they interact with each other through molecular and tactile signals. These findings suggest that more sophisticated models of SC dynamics should view SC populations as a collective and avoid the simplifying homogeneity assumption by accounting for the presence of more than one dividing sub-population, and their multi-fractal characteristics.

Bogdan, Paul; Deasy, Bridget M.; Gharaibeh, Burhan; Roehrs, Timo; Marculescu, Radu

2014-04-01

126

Heterogeneous structure of stem cells dynamics: statistical models and quantitative predictions.

Understanding stem cell (SC) population dynamics is essential for developing models that can be used in basic science and medicine, to aid in predicting cells fate. These models can be used as tools e.g. in studying patho-physiological events at the cellular and tissue level, predicting (mal)functions along the developmental course, and personalized regenerative medicine. Using time-lapsed imaging and statistical tools, we show that the dynamics of SC populations involve a heterogeneous structure consisting of multiple sub-population behaviors. Using non-Gaussian statistical approaches, we identify the co-existence of fast and slow dividing subpopulations, and quiescent cells, in stem cells from three species. The mathematical analysis also shows that, instead of developing independently, SCs exhibit a time-dependent fractal behavior as they interact with each other through molecular and tactile signals. These findings suggest that more sophisticated models of SC dynamics should view SC populations as a collective and avoid the simplifying homogeneity assumption by accounting for the presence of more than one dividing sub-population, and their multi-fractal characteristics. PMID:24769917

Bogdan, Paul; Deasy, Bridget M; Gharaibeh, Burhan; Roehrs, Timo; Marculescu, Radu

2014-01-01

127

Quantum particle statistics on the holographic screen leads to modified Newtonian dynamics

NASA Astrophysics Data System (ADS)

Employing a thermodynamic interpretation of gravity based on the holographic principle and assuming underlying particle statistics, fermionic or bosonic, for the excitations of the holographic screen leads to modified Newtonian dynamics (MOND). A connection between the acceleration scale a0 appearing in MOND and the Fermi energy of the holographic fermionic degrees of freedom is obtained. In this formulation the physics of MOND results from the quantum-classical crossover in the fermionic specific heat. However, due to the dimensionality of the screen, the formalism is general and applies to two-dimensional bosonic excitations as well. It is shown that replacing the assumption of the equipartition of energy on the holographic screen by a standard quantum-statistical-mechanics description wherein some of the degrees of freedom are frozen out at low temperatures is the physical basis for the MOND interpolating function ?˜. The interpolating function ?˜ is calculated within the statistical mechanical formalism and compared to the leading phenomenological interpolating functions, most commonly used. Based on the statistical mechanical view of MOND, its cosmological implications are reinterpreted: the connection between a0 and the Hubble constant is described as a quantum uncertainty relation; and the relationship between a0 and the cosmological constant is better understood physically.

Pazy, E.; Argaman, N.

2012-05-01

128

A review of gas-cooled reactor concepts for SDI (Strategic Defense Initiative)

NASA Astrophysics Data System (ADS)

A review was completed of multimegawatt gas cooled reactor concepts proposed for SDI applications. The study concluded that the principal reason for considering gas cooled reactors for burst mode operation was the potential for significant system mass savings over closed cycle systems if open cycle gas cooled operation (effluent exhausted to space) is acceptable. The principal reason for considering gas cooled reactors for steady state operation is that they may represent a lower technology risk than other approaches. In the review, nine gas cooled reactor concepts were compared to identify the most promising. For burst mode operation, the NERVA (Nuclear Engine for Rocket Vehicle Application) derivative reactor concept emerged as a strong first choice since its performance exceeds the anticipated operational requirements and the technology was demonstrated and is retrievable. Although the NERVA derivative concepts were determined to be the lead candidates for the Multimegawatt Steady State (MMWSS) mode as well, their lead over the other candidates is not as great as for the burst mode.

Marshall, A. C.

1989-08-01

129

Development of a current collection loss management system for SDI homopolar power supplies

High speed, high power density current collection systems have been identified as an enabling technology required to construct homopolar power supplies to meet SDI missions. This work is part of a three-year effort directed towards the analysis, experimental verification, and prototype construction of a current collection system designed to operate continuously at 2 kA/cm{sup 2}, at a rubbing speed of 200 m/s, and with acceptable losses in a space environment. To data, no system has achieved these conditions simultaneously. This is the annual report covering the second year period of performance on DOE contract DE-AC03-86SF16518. Major areas covered include design, construction and operation of a cryogenically cooled brush test rig, design and construction of a high speed brush test rig, optimization study for homopolar machines, loss analysis of the current collection system, and an application study which defines the air-core homopolar construction necessary to achieve the goal of 80--90 kW/kg generator power density. 17 figs., 2 tabs.

Brown, D.W.

1989-01-01

130

Development of a current collection loss management system for SDI homopolar power supplies

High speed, high power density current collection systems have been identified as an enabling technology required to construct homopolar power supplies to meet SDI missions. This work is part of a three-year effort directed towards the analysis, experimental verification, and prototype construction of a current collection system designed to operated continuously at 2 kA/cm{sup 2}, at a rubbing speed of 200 m/s, and with acceptable losses in a space environment. To data, no system has achieved these conditions simultaneously. This is the annual report covering the first year period of performance on DOE contract DE-AC03-86SF16518. Major areas covered include design and construction of a cryogenically-cooled brush test rig, design of a high speed brush test rig, loss analysis of the current collection system, and an application study which defines the air core homopolar construction necessary to achieve the goal of 80--90 kW/kg generator power density. 15 figs.

Hannan, W.F. III.

1987-01-01

131

Cluster Statistics and Quasisoliton Dynamics in Microscopic Car-following Models

Using the optimal velocity (OV) model as an example, we show that in the non-linear regime there is an emergent quantity that gives the extremum headways in the cluster formation, as well as the coexistence curve separating the absolute stable phase from the metastable phase. This emergent quantity is independent of the density of the traffic lane, and determines an intrinsic scale that characterizes the dynamics of localized quasisoliton structures given by the time derivative of the headways. The intrinsic scale is analogous to the "charge" of quasisolitons that controls the strength of interaction between multiple clusters, leading to non-trivial cluster statistics from random perturbations to initial uniform traffic. The cluster statistics depend both on the charge and the density of the traffic lane; the relationship is qualitatively universal for general car-following models.

Bo Yang; Xihua Xu; John Z. F. Pang; Christopher Monterola

2014-07-02

132

Dynamic whole body PET parametric imaging: II. Task-oriented statistical estimation

In the context of oncology, dynamic PET imaging coupled with standard graphical linear analysis has been previously employed to enable quantitative estimation of tracer kinetic parameters of physiological interest at the voxel level, thus, enabling quantitative PET parametric imaging. However, dynamic PET acquisition protocols have been confined to the limited axial field-of-view (~15–20cm) of a single bed position and have not been translated to the whole-body clinical imaging domain. On the contrary, standardized uptake value (SUV) PET imaging, considered as the routine approach in clinical oncology, commonly involves multi-bed acquisitions, but is performed statically, thus not allowing for dynamic tracking of the tracer distribution. Here, we pursue a transition to dynamic whole body PET parametric imaging, by presenting, within a unified framework, clinically feasible multi-bed dynamic PET acquisition protocols and parametric imaging methods. In a companion study, we presented a novel clinically feasible dynamic (4D) multi-bed PET acquisition protocol as well as the concept of whole body PET parametric imaging employing Patlak ordinary least squares (OLS) regression to estimate the quantitative parameters of tracer uptake rate Ki and total blood distribution volume V. In the present study, we propose an advanced hybrid linear regression framework, driven by Patlak kinetic voxel correlations, to achieve superior trade-off between contrast-to-noise ratio (CNR) and mean squared error (MSE) than provided by OLS for the final Ki parametric images, enabling task-based performance optimization. Overall, whether the observer's task is to detect a tumor or quantitatively assess treatment response, the proposed statistical estimation framework can be adapted to satisfy the specific task performance criteria, by adjusting the Patlak correlation-coefficient (WR) reference value. The multi-bed dynamic acquisition protocol, as optimized in the preceding companion study, was employed along with extensive Monte Carlo simulations and an initial clinical FDG patient dataset to validate and demonstrate the potential of the proposed statistical estimation methods. Both simulated and clinical results suggest that hybrid regression in the context of whole-body Patlak Ki imaging considerably reduces MSE without compromising high CNR. Alternatively, for a given CNR, hybrid regression enables larger reductions than OLS in the number of dynamic frames per bed, allowing for even shorter acquisitions of ~30min, thus further contributing to the clinical adoption of the proposed framework. Compared to the SUV approach, whole body parametric imaging can provide better tumor quantification, and can act as a complement to SUV, for the task of tumor detection. PMID:24080994

Karakatsanis, Nicolas A.; Lodge, Martin A.; Zhou, Y.; Wahl, Richard L.; Rahmim, Arman

2013-01-01

133

Dynamic whole-body PET parametric imaging: II. Task-oriented statistical estimation.

In the context of oncology, dynamic PET imaging coupled with standard graphical linear analysis has been previously employed to enable quantitative estimation of tracer kinetic parameters of physiological interest at the voxel level, thus, enabling quantitative PET parametric imaging. However, dynamic PET acquisition protocols have been confined to the limited axial field-of-view (~15-20 cm) of a single-bed position and have not been translated to the whole-body clinical imaging domain. On the contrary, standardized uptake value (SUV) PET imaging, considered as the routine approach in clinical oncology, commonly involves multi-bed acquisitions, but is performed statically, thus not allowing for dynamic tracking of the tracer distribution. Here, we pursue a transition to dynamic whole-body PET parametric imaging, by presenting, within a unified framework, clinically feasible multi-bed dynamic PET acquisition protocols and parametric imaging methods. In a companion study, we presented a novel clinically feasible dynamic (4D) multi-bed PET acquisition protocol as well as the concept of whole-body PET parametric imaging employing Patlak ordinary least squares (OLS) regression to estimate the quantitative parameters of tracer uptake rate Ki and total blood distribution volume V. In the present study, we propose an advanced hybrid linear regression framework, driven by Patlak kinetic voxel correlations, to achieve superior trade-off between contrast-to-noise ratio (CNR) and mean squared error (MSE) than provided by OLS for the final Ki parametric images, enabling task-based performance optimization. Overall, whether the observer's task is to detect a tumor or quantitatively assess treatment response, the proposed statistical estimation framework can be adapted to satisfy the specific task performance criteria, by adjusting the Patlak correlation-coefficient (WR) reference value. The multi-bed dynamic acquisition protocol, as optimized in the preceding companion study, was employed along with extensive Monte Carlo simulations and an initial clinical (18)F-deoxyglucose patient dataset to validate and demonstrate the potential of the proposed statistical estimation methods. Both simulated and clinical results suggest that hybrid regression in the context of whole-body Patlak Ki imaging considerably reduces MSE without compromising high CNR. Alternatively, for a given CNR, hybrid regression enables larger reductions than OLS in the number of dynamic frames per bed, allowing for even shorter acquisitions of ~30 min, thus further contributing to the clinical adoption of the proposed framework. Compared to the SUV approach, whole-body parametric imaging can provide better tumor quantification, and can act as a complement to SUV, for the task of tumor detection. PMID:24080994

Karakatsanis, Nicolas A; Lodge, Martin A; Zhou, Y; Wahl, Richard L; Rahmim, Arman

2013-10-21

134

Dynamic whole-body PET parametric imaging: II. Task-oriented statistical estimation

NASA Astrophysics Data System (ADS)

In the context of oncology, dynamic PET imaging coupled with standard graphical linear analysis has been previously employed to enable quantitative estimation of tracer kinetic parameters of physiological interest at the voxel level, thus, enabling quantitative PET parametric imaging. However, dynamic PET acquisition protocols have been confined to the limited axial field-of-view (˜15-20 cm) of a single-bed position and have not been translated to the whole-body clinical imaging domain. On the contrary, standardized uptake value (SUV) PET imaging, considered as the routine approach in clinical oncology, commonly involves multi-bed acquisitions, but is performed statically, thus not allowing for dynamic tracking of the tracer distribution. Here, we pursue a transition to dynamic whole-body PET parametric imaging, by presenting, within a unified framework, clinically feasible multi-bed dynamic PET acquisition protocols and parametric imaging methods. In a companion study, we presented a novel clinically feasible dynamic (4D) multi-bed PET acquisition protocol as well as the concept of whole-body PET parametric imaging employing Patlak ordinary least squares (OLS) regression to estimate the quantitative parameters of tracer uptake rate Ki and total blood distribution volume V. In the present study, we propose an advanced hybrid linear regression framework, driven by Patlak kinetic voxel correlations, to achieve superior trade-off between contrast-to-noise ratio (CNR) and mean squared error (MSE) than provided by OLS for the final Ki parametric images, enabling task-based performance optimization. Overall, whether the observer's task is to detect a tumor or quantitatively assess treatment response, the proposed statistical estimation framework can be adapted to satisfy the specific task performance criteria, by adjusting the Patlak correlation-coefficient (WR) reference value. The multi-bed dynamic acquisition protocol, as optimized in the preceding companion study, was employed along with extensive Monte Carlo simulations and an initial clinical 18F-deoxyglucose patient dataset to validate and demonstrate the potential of the proposed statistical estimation methods. Both simulated and clinical results suggest that hybrid regression in the context of whole-body Patlak Ki imaging considerably reduces MSE without compromising high CNR. Alternatively, for a given CNR, hybrid regression enables larger reductions than OLS in the number of dynamic frames per bed, allowing for even shorter acquisitions of ˜30 min, thus further contributing to the clinical adoption of the proposed framework. Compared to the SUV approach, whole-body parametric imaging can provide better tumor quantification, and can act as a complement to SUV, for the task of tumor detection.

Karakatsanis, Nicolas A.; Lodge, Martin A.; Zhou, Y.; Wahl, Richard L.; Rahmim, Arman

2013-10-01

135

The Melick method of inlet flow dynamic distortion prediction by statistical means is outlined. A hypothetic vortex model is used as the basis for the mathematical formulations. The main variables are identified by matching the theoretical total pressure rms ratio with the measured total pressure rms ratio. Data comparisons, using the HiMAT inlet test data set, indicate satisfactory prediction of the dynamic peak distortion for cases with boundary layer control device vortex generators. A method for the dynamic probe selection was developed. Validity of the probe selection criteria is demonstrated by comparing the reduced-probe predictions with the 40-probe predictions. It is indicated that the the number of dynamic probes can be reduced to as few as two and still retain good accuracy.

Schweikhard, W.G.; Chen, Y.S.

1986-04-01

136

Summary An improved statistical-dynamical downscaling method for the regionalization of large-scale climate analyses or simulations\\u000a is introduced. The method is based on the disaggregation of a multi-year time-series of large-scale meteorological data into\\u000a multi-day episodes of quasi-stationary circulation. The episodes are subsequently grouped into a defined number of classes.\\u000a A regional model is used to simulate the evolution of weather

U. Fuentes; D. Heimann

2000-01-01

137

On Monte Carlo and molecular dynamics methods inspired by Tsallis statistics: Methodology Generalized Monte Carlo and molecular dynamics algorithms which provide enhanced sampling of the phase space is made with standard Metropolis Monte Carlo and the J-walking algorithm of Franz, Freeman and Doll

Straub, John E.

138

Dynamics of the environments of complex systems such as biomolecules, polar solvents, and glass plays an important role in controlling electron transfer reactions. The kinetics is determined by the nature of a complex multidimensional landscape. By quantifying the mean and high-order statistics of the first-passage time and the associated ratios, the dynamics in electron transfer reactions controlled by the environments

Luciana C. Paula; Jin Wang; Vitor B. P. Leite

2008-01-01

139

Statistics of reversible bond dynamics observed in force-clamp spectroscopy

We present a detailed analysis of two-state trajectories obtained from force-clamp spectroscopy (FCS) of reversibly bonded systems. FCS offers the unique possibility to vary the equilibrium constant in two-state kinetics, for instance the unfolding and refolding of biomolecules, over many orders of magnitude due to the force dependency of the respective rates. We discuss two different kinds of counting statistics, the event-counting usually employed in the statistical analysis of two-state kinetics and additionally the so-called cycle-counting. While in the former case all transitions are counted, cycle-counting means that we focus on one type of transitions. This might be advantageous in particular if the equilibrium constant is much larger or much smaller than unity because in these situations the temporal resolution of the experimental setup might not allow to capture all transitions of an event-counting analysis. We discuss how an analysis of FCS data for complex systems exhibiting dynamic disorder might be performed yielding information about the detailed force-dependence of the transition rates and about the time scale of the dynamic disorder. In addition, the question as to which extent the kinetic scheme can be viewed as a Markovian two-state model is discussed.

Gregor Diezemann; Thomas Schlesier; Burkhard Geil; Andreas Janshoff

2010-10-30

140

NASA Astrophysics Data System (ADS)

A prerequisite of a successful statistical downscaling is that large-scale predictors simulated by the General Circulation Model (GCM) must be realistic. It is assumed here that features smaller than the GCM resolution are important in determining the realism of the large-scale predictors. It is tested whether a three-step method can improve conventional one-step statistical downscaling. The method uses predictors that are upscaled from a dynamical downscaling instead of predictors taken directly from a GCM simulation. The method is applied to downscaling of monthly precipitation in Sweden. The statistical model used is a multiple regression model that uses indices of large-scale atmospheric circulation and 850-hPa specific humidity as predictors. Data from two GCMs (HadCM2 and ECHAM4) and two RCM experiments of the Rossby Centre model (RCA1) driven by the GCMs are used. It is found that upscaled RCA1 predictors capture the seasonal cycle better than those from the GCMs, and hence increase the reliability of the downscaled precipitation. However, there are only slight improvements in the simulation of the seasonal cycle of downscaled precipitation. Due to the cost of the method and the limited improvements in the downscaling results, the three-step method is not justified to replace the one-step method for downscaling of Swedish precipitation.

Hellström, Cecilia; Chen, Deliang

2003-11-01

141

Statistical analysis of nonlinear dynamical systems using differential geometric sampling methods

Mechanistic models based on systems of nonlinear differential equations can help provide a quantitative understanding of complex physical or biological phenomena. The use of such models to describe nonlinear interactions in molecular biology has a long history; however, it is only recently that advances in computing have allowed these models to be set within a statistical framework, further increasing their usefulness and binding modelling and experimental approaches more tightly together. A probabilistic approach to modelling allows us to quantify uncertainty in both the model parameters and the model predictions, as well as in the model hypotheses themselves. In this paper, the Bayesian approach to statistical inference is adopted and we examine the significant challenges that arise when performing inference over nonlinear ordinary differential equation models describing cell signalling pathways and enzymatic circadian control; in particular, we address the difficulties arising owing to strong nonlinear correlation structures, high dimensionality and non-identifiability of parameters. We demonstrate how recently introduced differential geometric Markov chain Monte Carlo methodology alleviates many of these issues by making proposals based on local sensitivity information, which ultimately allows us to perform effective statistical analysis. Along the way, we highlight the deep link between the sensitivity analysis of such dynamic system models and the underlying Riemannian geometry of the induced posterior probability distributions. PMID:23226584

Calderhead, Ben; Girolami, Mark

2011-01-01

142

NASA Astrophysics Data System (ADS)

Minimum and maximum temperature in two regional climate models and five statistical downscaling models are validated according to a unified set of criteria that have a potential relevance for impact assessments: persistence (temporal autocorrelations), spatial autocorrelations, extreme quantiles, skewness, kurtosis, and the degree of fit to observed data on both short and long times scales. The validation is conducted on two dense grids in central Europe as follows: (1) a station network and (2) a grid with a resolution of 10 km. The gridded dataset is not contaminated by artifacts of the interpolation procedure; therefore, we claim that using a gridded dataset as a validation base is a valid approach. The fit to observations in short time scales is equally good for the statistical downscaling (SDS) models and regional climate models (RCMs) in winter, while it is much better for the SDS models in summer. The reproduction of variability on long time scales, expressed as linear trends, is similarly successful by both SDS models and RCMs. Results for other criteria suggest that there is no justification for preferring dynamical models at the expense of statistical models—and vice versa. The non-linear SDS models do not outperform the linear ones.

Huth, Radan; Mikšovský, Ji?í; Št?pánek, Petr; Belda, Michal; Farda, Aleš; Chládová, Zuzana; Pišoft, Petr

2014-06-01

143

A Statistical Approach for the Concurrent Coupling of Molecular Dynamics and Finite Element Methods

NASA Technical Reports Server (NTRS)

Molecular dynamics (MD) methods are opening new opportunities for simulating the fundamental processes of material behavior at the atomistic level. However, increasing the size of the MD domain quickly presents intractable computational demands. A robust approach to surmount this computational limitation has been to unite continuum modeling procedures such as the finite element method (FEM) with MD analyses thereby reducing the region of atomic scale refinement. The challenging problem is to seamlessly connect the two inherently different simulation techniques at their interface. In the present work, a new approach to MD-FEM coupling is developed based on a restatement of the typical boundary value problem used to define a coupled domain. The method uses statistical averaging of the atomistic MD domain to provide displacement interface boundary conditions to the surrounding continuum FEM region, which, in return, generates interface reaction forces applied as piecewise constant traction boundary conditions to the MD domain. The two systems are computationally disconnected and communicate only through a continuous update of their boundary conditions. With the use of statistical averages of the atomistic quantities to couple the two computational schemes, the developed approach is referred to as an embedded statistical coupling method (ESCM) as opposed to a direct coupling method where interface atoms and FEM nodes are individually related. The methodology is inherently applicable to three-dimensional domains, avoids discretization of the continuum model down to atomic scales, and permits arbitrary temperatures to be applied.

Saether, E.; Yamakov, V.; Glaessgen, E.

2007-01-01

144

NASA Astrophysics Data System (ADS)

Changes in monthly temperature and precipitation at stations in two small areas placed in western (Banat Plain) and southwestern (Oltenia Plain) part of Romania for the periods 2021-2050 and 2071-2100 (compared to 1961-1990), under the IPCC A1B scenario, are estimated through two downscaling techniques (statistical-SDM and dynamical-RCM). These results were obtained within the SEE project CC-WaterS (www.ccwaters.eu). The statistical downscaling technique uses a model based on canonical correlation analysis (CCA). New improvement is achieved in this paper comparing to other previous studies, mainly referring to the combination of the local standardized temperature and precipitation anomalies (11 stations) in a single spatial vector considered as predictand, giving more physical consistence to the results. Various predictors were tested to find the optimum statistical downscaling model (SDM): the temperature at 850 hPa (T850), sea level pressure (SLP) and specific humidity at 700 hPa (SH700), either used individually or together. The observed predictand data are based on homogenized dataset. It was found that the T850 is good predictor for all seasons but the combination between the three predictors gives higher skill (in terms of explained variance) for winter and similar skill for other seasons. From physical reasons both versions were retained in order to analyse the uncertainty (similar skill should give similar future climate change signal if the statistical relationship will be also valid in the future and all predictors capture the entire climate change signal). The model was fitted with the data set for the period 1961-1990 and validated over the independent data set 1991-2007.The optimum statistical downscaling model, established over the independent data set for each season, has been then applied to predictors from the A1B scenario simulations of the ENSEMBLES RCMs (http://ensemblesrt3.dmi.dk), RegCM3 and CNRM, driven by the global models ECHAM5 (run 3) and ARPEGE, respectively. To estimate the uncertainty related to the downscaling technique (dynamical or statistical), the results achieved through the statistical downscaling model (SDM) applied to the global model ECHAM5 have been compared to those derived directly from 5 RCMs (including RegCM3) with the same driver as well as with those derived from the SDM applied to the two mentioned RCMs. The final ensemble achieved from 8 ENSEMBLES RCM outputs and SDM outputs has been considered to estimate the uncertainty associated to the climate change signal at the 11 stations. The optimum (most plausible) climate change signal (represented by the ensemble average) and the model spread (represented by the standard deviation of the 10 values) have been computed. The uncertainties related to the RCMs/GCM skill in reproducing the predictor variability are analysed in details for the pair RegCM3-ECHAM5.

Busuioc, A.; Dumitrescu, A.; Baciu, M.; Cazacioc, L.

2012-04-01

145

Statistical analysis of a new European Cloud Dynamics and Radiation Database

NASA Astrophysics Data System (ADS)

Physically-based algorithms for the retrieval of precipitation from satellite-borne microwave (MW) radiometers, make use of Cloud Radiation Databases (CRD's) that are composed of thousands of detailed microphysical cloud profiles, obtained from Cloud Resolving Model (CRM) simulations, coupled with the corresponding brightness temperatures (TB's), calculated by applying Radiative Transfer (RT) schemes to the CRM outputs. Usually, CRD's are generated on the basis of CRM simulations of past precipitation events and then utilized for the analysis of satellite observations of new events. Notably, retrieval precision and accuracy is strictly related to the appropriate generation of the cloud profile datasets associated to the typologies of the observed precipitation events more than to an a-posteriori statistical treatment of uncertainties. In essence, the retrieval performance can be improved by generating a statistically significant CRD by means of a large number of different CRM simulations representing all precipitation regimes that are of interest for the zone(s) and season(s) under investigation. In addition, it should be noted that despite some reasonable successes with the CRD and the Bayesian approach, there is a considerable reservoir of potential information available that has not been yet tapped. This ancillary information exists in the knowledge of the "synoptic situation" of the considered event and the geographical and temporal location of the event. This knowledge renders some entries into the CRD more relevant than others by virtue of how similar the circumstances of the simulated events are to those of the event for which the database is applied. We can capture this information in the form of "dynamical tags" which can be used to link a satellite-observed event to a subset of the entire CRD using an independent estimate of these tags. To accomplish this, we have expanded the CRD approach so as to include these "dynamical tags" and have developed a new passive MW precipitation retrieval algorithm which employs these tags in addition to the upwelling TB's. We call these the Cloud Dynamics and Radiation Database (CDRD) approach and the CDRD Algorithm, respectively. Recently, we have generated a CDRD database for Europe using a large amount of CRM simulations of precipitating systems over this area by means of the "University of Wisconsin - Non-hydrostatic Modeling System" (UW-NMS). In our presentation, we will briefly review the main design features of the CDRD approach and will show an analysis of the statistical properties of this highly-populated European CDRD database. Finally, we will compare its radiative characteristics with an equivalent set of MW radiometric measurements from polar satellites.

Casella, D.; Formenton, M.; Leung, W.-Y.; Mugnai, A.; Sanò, P.; Smith, E. A.; Tripoli, G. J.

2009-04-01

146

Kinematic and dynamic collision statistics of cloud droplets from high-resolution simulations

NASA Astrophysics Data System (ADS)

We study the dynamic and kinematic collision statistics of cloud droplets for a range of flow Taylor microscale Reynolds numbers (up to 500), using a highly scalable hybrid direct numerical simulation approach. Accurate results of radial relative velocity (RRV) and radial distribution function (RDF) at contact have been obtained by taking advantage of their power-law scaling at short separation distances. Three specific but inter-related questions have been addressed in a systematic manner for geometric collisions of same-size droplets (of radius from 10 to 60 ?m) in a typical cloud turbulence (dissipation rate at 400 cm2 s-3). Firstly, both deterministic and stochastic forcing schemes were employed to test the sensitivity of the simulation results on the large-scale driving mechanism. We found that, in general, the results are quantitatively similar, with the deterministic forcing giving a slightly larger RDF and collision kernel. This difference, however, is negligible for droplets of radius less than 30 ?m. Secondly, we have shown that the dependence of pair statistics on the flow Reynolds number R? or larger scale fluid motion is of secondary importance, with a tendency for this effect to saturate at high enough R? leading to R?-independent results. Both DNS results and theoretical arguments show that the saturation happens at a smaller R? for smaller droplets. Finally, since most previous studies of turbulent collision of inertial particles concerned non-sedimenting particles, we have specifically addressed the role of gravity on collision statistics, by simultaneously simulating collision statistics with and without gravity. It is shown that the collision statistics is not affected by gravity when a < ac, where the critical droplet radius ac is found to be around 30 ?m for the RRV, and around 20 ?m for the RDF. For larger droplets, gravity alters the particle-eddy interaction time and significantly reduces the RRV. The effect of gravity on the RDF is rather complex: gravity reduces the RDF for intermediate-sized droplets but enhances the RDF for larger droplets. In addition, we have studied the scaling exponents of both RDF and RRV, and found that gravity modifies the RDF scaling exponents for both intermediate and large particles, in a manner very similar to the effect of gravity on the RDF at contact. Gravity is shown to cause the scaling exponents for RDF and RRV to level off for large droplets, in contrast to diminishing exponents for non-sedimenting particles.

Rosa, Bogdan; Parishani, Hossein; Ayala, Orlando; Grabowski, Wojciech W.; Wang, Lian-Ping

2013-04-01

147

NASA Astrophysics Data System (ADS)

We introduce a new dynamic statistical optimization algorithm to initialize ionosphere-corrected bending angles of Global Navigation Satellite System (GNSS) based radio occultation (RO) measurements. The new algorithm estimates background and observation error covariance matrices with geographically-varying uncertainty profiles and realistic global-mean correlation matrices. The error covariance matrices estimated by the new approach are more accurate and realistic than in simplified existing approaches and can therefore be used in statistical optimization to provide optimal bending angle profiles for high-altitude initialization of the subsequent Abel transform retrieval of refractivity. The new algorithm is evaluated against the existing Wegener Center Occultation Processing System version 5.6 (OPSv5.6) algorithm, using simulated data on two test days from January and July 2008 and real observed CHAMP and COSMIC measurements from the complete months of January and July 2008. The following is achieved for the new method's performance compared to OPSv5.6: (1) significant reduction in random errors (standard deviations) of optimized bending angles down to about two-thirds of their size or more; (2) reduction of the systematic differences in optimized bending angles for simulated MetOp data; (3) improved retrieval of refractivity and temperature profiles; (4) produces realistically estimated global-mean correlation matrices and realistic uncertainty fields for the background and observations. Overall the results indicate high suitability for employing the new dynamic approach in the processing of long-term RO data into a reference climate record, leading to well characterized and high-quality atmospheric profiles over the entire stratosphere.

Li, Y.; Kirchengast, G.; Scherllin-Pirscher, B.; Norman, R.; Yuan, Y. B.; Fritzer, J.; Schwaerz, M.; Zhang, K.

2015-01-01

148

Highlights: {yields} Reduced p21 expression in senescent cells treated with DNA damaging agents. {yields} Increase of [{sup 3}H]thymidine and BrdU incorporations in DNA damaged-senescent cells. {yields} Upregulation of miR-93 expression in senescent cells in response to DSB. {yields} Failure of p53 binding to p21 promoter in senescent cells in response to DSB. {yields} Molecular mechanism of increased cancer development in aged than young individuals. -- Abstract: To answer what is a critical event for higher incidence of tumor development in old than young individuals, primary culture of human diploid fibroblasts were employed and DNA damage was induced by doxorubicin or X-ray irradiation. Response to the damage was different between young and old cells; loss of p21{sup sdi1} expression in spite of p53{sup S15} activation in old cells along with [{sup 3}H]thymidine and BrdU incorporation, but not in young cells. The phenomenon was confirmed by other tissue fibroblasts obtained from different donor ages. Induction of miR-93 expression and reduced p53 binding to p21 gene promoter account for loss of p21{sup sdi1} expression in senescent cells after DNA damage, suggesting a mechanism of in vivo carcinogenesis in aged tissue without repair arrest.

Choi, Ok Ran [Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, Suwon 443-721 (Korea, Republic of)] [Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, Suwon 443-721 (Korea, Republic of); Lim, In Kyoung, E-mail: iklim@ajou.ac.kr [Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, Suwon 443-721 (Korea, Republic of)

2011-04-08

149

Statistical-dynamical downscaling for the future urban climate of Hamburg, Germany

NASA Astrophysics Data System (ADS)

In the framework of the interdisciplinary project KLIMZUG-NORD, adaptation measures to climate change are developed for the Metropolitan Region of Hamburg. For the development of these measures it is crucial to know how the urban climate of Hamburg, a city with a population of 1.8 Mio, will alter due to climate change. Regional climate models provide climate projections on a horizontal resolution of up to 10 km, which is still too coarse to sufficiently simulate urban related phenomena such as the urban heat island (UHI). Therefore, these climate projections have to be downscaled. Since the computational amount increases rapidly with increasing horizontal resolution, a statistical-dynamical method for the UHI was developed. As a first step of the downscaling method, synoptic situations which are relevant for the UHI are determined. This is done combining objective weather type classification of ERA-40 reanalysis data using k-means-based cluster analysis and a regression-based statistical model for the observed UHI of Hamburg. The meteorological variables and domain used for the weather type classification are chosen to explain the variability of the UHI as best as possible. The second step is the simulation of the resulting synoptic situations with the mesoscale meteorological model METRAS providing a horizontal resolution of 1 km. To get the average UHI for a certain period, the simulation results are statistically recombined according to the frequency of the synoptic weather types. This is done for present and future climate simulations for the A1B scenario conducted with the regional climate models REMO and CLM and for the A2 scenario conducted with the regional climate model CCAM to identify changes in Hamburg's UHI. In this presentation the method will be presented with focus on the weather type classification and on the simulation results for the summer season.

Hoffmann, P.; Flagg, D. D.; Grawe, D.; Katzfey, J. J.; Kirschner, P.; Linde, M.; Schlünzen, K. H.; Schoetter, R.

2011-12-01

150

NASA Astrophysics Data System (ADS)

During boreal spring, eastern portions of Kenya and Somalia have experienced more frequent droughts since 1999. Given the region's high levels of food insecurity, better predictions of these droughts could provide substantial humanitarian benefits. We show that dynamical-statistical seasonal climate forecasts, based on the latest generation of coupled atmosphere-ocean and uncoupled atmospheric models, effectively predict boreal spring rainfall in this area. Skill sources are assessed by comparing ensembles driven with full-ocean forcing with ensembles driven with ENSO-only sea surface temperatures (SSTs). Our analysis suggests that both ENSO and non-ENSO Indo-Pacific SST forcing have played an important role in the increase in drought frequencies. Over the past 30 years, La Niña drought teleconnections have strengthened, while non-ENSO Indo-Pacific convection patterns have also supported increased (decreased) Western Pacific (East African) rainfall. To further examine the relative contribution of ENSO, low frequency warming and the Pacific Decadal Oscillation, we present decompositions of ECHAM5, GFS, CAM4 and GMAO AMIP simulations. These decompositions suggest that rapid warming in the western Pacific and steeper western-to-central Pacific SST gradients have likely played an important role in the recent intensification of the Walker circulation, and the associated increase in East African aridity. A linear combination of time series describing the Pacific Decadal Oscillation and the strength of Indo-Pacific warming are shown to track East African rainfall reasonably well. The talk concludes with a few thoughts linking the potentially important interplay of attribution and prediction. At least for recent East African droughts, it appears that a characteristic Indo-Pacific SST and precipitation anomaly pattern can be linked statistically to support forecasts and attribution analyses. The combination of traditional AGCM attribution analyses with simple yet physically plausible statistical estimation procedures may help us better untangle some climate mysteries.

Funk, C. C.; Shukla, S.; Hoerling, M. P.; Robertson, F. R.; Hoell, A.; Liebmann, B.

2013-12-01

151

NASA Astrophysics Data System (ADS)

In this investigation, exact particular realizations are sought for the microscopic statistical description which is associated with the classical dynamical system (CDS) formed by N identical smooth hard spheres subject to elastic collisions ( S N -CDS). The problem is posed in the framework of the ab initio statistical description of S N -CDS recently developed. It is shown that the Liouville equation associated with SN-CDS admits an exact particular solution for the N-body probability density function (PDF). This is factorized in terms of the i-th particle 1-body PDF (for all i = 1, N) via suitable weighting factors, which are denoted here as particle occupation coefficients. The latter are found to depend functionally only on the 1-body PDFs which are associated with each of the remaining particles belonging to S N -CDS. Furthermore, the 1-body PDF is proved to obey a well-defined statistical equation, referred to here as Master kinetic equation. This is an exact kinetic equation which takes into account the occurrence of configuration-space correlations due to the finite size of the extended particles, while depending functionally on the same 1-body PDF only. The asymptotic approximation of the Master equation, which holds in validity of the Boltzmann-Grad limit, is shown to recover in a suitable asymptotic sense the customary Boltzmann equation. Finally, a critical analysis is presented of the original and modified versions of the Enskog kinetic equation, as well as of some of the non-linear kinetic approaches formulated in the past for dense granular gases. Their conditions of validity and main differences with respect to the present theory are pointed out.

Tessarotto, Massimo; Cremaschini, Claudio

2014-07-01

152

An Embedded Statistical Method for Coupling Molecular Dynamics and Finite Element Analyses

NASA Technical Reports Server (NTRS)

The coupling of molecular dynamics (MD) simulations with finite element methods (FEM) yields computationally efficient models that link fundamental material processes at the atomistic level with continuum field responses at higher length scales. The theoretical challenge involves developing a seamless connection along an interface between two inherently different simulation frameworks. Various specialized methods have been developed to solve particular classes of problems. Many of these methods link the kinematics of individual MD atoms with FEM nodes at their common interface, necessarily requiring that the finite element mesh be refined to atomic resolution. Some of these coupling approaches also require simulations to be carried out at 0 K and restrict modeling to two-dimensional material domains due to difficulties in simulating full three-dimensional material processes. In the present work, a new approach to MD-FEM coupling is developed based on a restatement of the standard boundary value problem used to define a coupled domain. The method replaces a direct linkage of individual MD atoms and finite element (FE) nodes with a statistical averaging of atomistic displacements in local atomic volumes associated with each FE node in an interface region. The FEM and MD computational systems are effectively independent and communicate only through an iterative update of their boundary conditions. With the use of statistical averages of the atomistic quantities to couple the two computational schemes, the developed approach is referred to as an embedded statistical coupling method (ESCM). ESCM provides an enhanced coupling methodology that is inherently applicable to three-dimensional domains, avoids discretization of the continuum model to atomic scale resolution, and permits finite temperature states to be applied.

Saether, E.; Glaessgen, E.H.; Yamakov, V.

2008-01-01

153

NASA Astrophysics Data System (ADS)

Global circulation models (GCM) are increasingly capable of making relevant predictions of seasonal and long-term climate variability, thus improving prospects of predicting impact on crop yields. This is particularly important for semi-arid West Africa where climate variability and drought threaten food security. Translating GCM outputs into attainable crop yields is difficult because GCM grid boxes are of larger scale than the processes governing yield, involving partitioning of rain among runoff, evaporation, transpiration, drainage and storage at plot scale. It therefore requires the use of downscaling methods. This study analyzes the performance of both dynamical and statistical downscaling techniques in simulating crop yield at local scale. A detailed case study is conducted using historical weather data for Senegal, applied to the crop model SARRAH for simulating several tropical cereals (sorghum, millet, maize) at local scale. This control simulation is used as a benchmark to evaluate a set of Regional Climate Models (RCM) simulations, forced by ERA-Interim, from the ENSEMBLES project and a statistical downscaling method, the CDF-Transform, used to correct biases in RCM outputs. We first evaluate each climate variable that drives the simulated yield in the control simulation (radiation, rainfall, temperatures). We then simulate crop yields with RCM outputs (with or without applying the CDG-Transform) and evaluate the performance of each RCM in regards to crop yield simulations.

Sultan, B.; Oettli, P.; Vrac, M.; Baron, C.

2010-12-01

154

The classical and quantum evolution of a generic probability distribution is analyzed. To that end, a formalism based on the decomposition of the distribution in terms of its statistical moments is used, which makes explicit the differences between the classical and quantum dynamics. In particular, there are two different sources of quantum effects. Distributional effects, which are also present in the classical evolution of an extended distribution, are due to the fact that all moments can not be vanishing because of the Heisenberg uncertainty principle. In addition, the non-commutativity of the basic quantum operators add some terms to the quantum equations of motion that explicitly depend on the Planck constant and are not present in the classical setting. These are thus purely-quantum effects. Some particular Hamiltonians are analyzed that have very special properties regarding the evolution they generate in the classical and quantum sector. In addition, a large class of inequalities obeyed by high-order statistical moments, and in particular uncertainty relations that bound the information that is possible to obtain from a quantum system, are derived.

David Brizuela

2014-11-03

155

NASA Astrophysics Data System (ADS)

The classical and quantum evolution of a generic probability distribution is analyzed. To that end, a formalism based on the decomposition of the distribution in terms of its statistical moments is used, which makes explicit the differences between the classical and quantum dynamics. In particular, there are two different sources of quantum effects. Distributional effects, which are also present in the classical evolution of an extended distribution, are due to the fact that all moments cannot be vanishing because of the Heisenberg uncertainty principle. In addition, the noncommutativity of the basic quantum operators add some terms to the quantum equations of motion that explicitly depend on the Planck constant and are not present in the classical setting. These are thus purely quantum effects. Some particular Hamiltonians are analyzed that have very special properties regarding the evolution they generate in the classical and quantum sector. In addition, a large class of inequalities obeyed by high-order statistical moments, and in particular uncertainty relations that bound the information that is possible to obtain from a quantum system, are derived.

Brizuela, David

2014-10-01

156

The ideal quantum gas dynamics as manifested by the semiclassical ellipsoidal-statistical (ES) equilibrium distribution derived in Wu et al. (Wu et al. 2012 Proc. R. Soc. A 468, 1799-1823 (doi:10.1098/rspa.2011.0673)) is numerically studied for particles of three statistics. This anisotropic ES equilibrium distribution was derived using the maximum entropy principle and conserves the mass, momentum and energy, but differs from the standard Fermi-Dirac or Bose-Einstein distribution. The present numerical method combines the discrete velocity (or momentum) ordinate method in momentum space and the high-resolution shock-capturing method in physical space. A decoding procedure to obtain the necessary parameters for determining the ES distribution is also devised. Computations of two-dimensional Riemann problems are presented, and various contours of the quantities unique to this ES model are illustrated. The main flow features, such as shock waves, expansion waves and slip lines and their complex nonlinear interactions, are depicted and found to be consistent with existing calculations for a classical gas. PMID:24399919

Yang, Jaw-Yen; Yan, Chih-Yuan; Diaz, Manuel; Huang, Juan-Chen; Li, Zhihui; Zhang, Hanxin

2014-01-01

157

The ideal quantum gas dynamics as manifested by the semiclassical ellipsoidal-statistical (ES) equilibrium distribution derived in Wu et al. (Wu et al. 2012 Proc. R. Soc. A 468, 1799–1823 (doi:10.1098/rspa.2011.0673)) is numerically studied for particles of three statistics. This anisotropic ES equilibrium distribution was derived using the maximum entropy principle and conserves the mass, momentum and energy, but differs from the standard Fermi–Dirac or Bose–Einstein distribution. The present numerical method combines the discrete velocity (or momentum) ordinate method in momentum space and the high-resolution shock-capturing method in physical space. A decoding procedure to obtain the necessary parameters for determining the ES distribution is also devised. Computations of two-dimensional Riemann problems are presented, and various contours of the quantities unique to this ES model are illustrated. The main flow features, such as shock waves, expansion waves and slip lines and their complex nonlinear interactions, are depicted and found to be consistent with existing calculations for a classical gas. PMID:24399919

Yang, Jaw-Yen; Yan, Chih-Yuan; Diaz, Manuel; Huang, Juan-Chen; Li, Zhihui; Zhang, Hanxin

2014-01-01

158

NASA Astrophysics Data System (ADS)

Equatorial deep jets (EDJs) are persistent, zonally-coherent jets found within one degree of the equator in all ocean basins (Luyten and Swallow, 1976). The jets are characterized by a vertically oscillating ('stacked') structure between ~500-2000m depth, with jet amplitudes on the order of 10 cm/s superimposed upon a large-scale background shear flow. EDJs are a striking feature of the equatorial climate system and play an important role in equatorial ocean transport. However, the physical mechanism responsible for the presence of EDJs remains uncertain. Previous theoretical models for EDJs have suggested mechanisms involving the reflection and constructive interference of equatorially trapped waves (Wunsch 1977, McCreary 1984) and the instability of mixed Rossby-gravity waves with EDJs as the fastest-growing eigenfunction (Hua et al. 2008, Eden et al. 2008). In this work we explore the jet formation mechanism and the parameter dependence of EDJ structure in the idealized theoretical model of the stochastically-driven equatorial beta plane. The model is formulated in three ways: 1) Fully nonlinear equations of motion 2) Quasilinear (or mean-field) dynamics 3) Statistical state dynamics employing a second order closure method (stochastic structural stability theory). Results from the three models are compared, and the implications for both the jet formation and equilibration mechanisms, as well as the role of eddy-eddy nonlinearity in the EDJ system, are discussed.

Fitzgerald, J.; Farrell, B.

2013-12-01

159

NASA Astrophysics Data System (ADS)

The idea that quantum randomness can be reduced to randomness of classical fields (fluctuating at time and space scales which are essentially finer than scales approachable in modern quantum experiments) is rather old. Various models have been proposed, e.g., stochastic electrodynamics or the semiclassical model. Recently a new model, so called prequantum classical statistical field theory (PCSFT), was developed. By this model a "quantum system" is just a label for (so to say "prequantum") classical random field. Quantum averages can be represented as classical field averages. Correlations between observables on subsystems of a composite system can be as well represented as classical correlations. In particular, it can be done for entangled systems. Creation of such classical field representation demystifies quantum entanglement. In this paper we show that quantum dynamics (given by Schrödinger's equation) of entangled systems can be represented as the stochastic dynamics of classical random fields. The "effect of entanglement" is produced by classical correlations which were present at the initial moment of time, cf. views of Albert Einstein.

Khrennikov, Andrei

2011-03-01

160

NASA Astrophysics Data System (ADS)

In spite of dense meteorological observation conducting over South Korea (The average distance between stations: ~ 12.7km), the detailed topographical effect is not reflected properly due to its mountainous terrains and observation sites mostly situated on low altitudes. A model represents such a topographical effect well, but due to systematic biases in the model, the general temperature distribution is sometimes far different from actual observation. This study attempts to produce a detailed mean temperature distribution for South Korea through a method combining dynamical downscaling and statistical correction. For the dynamical downscaling, a multi-nesting technique is applied to obtain 3-km resolution data with a focus on the domain for the period of 10 years (1999-2008). For the correction of systematic biases, a perturbation method divided into the mean and the perturbation part was used with a different correction method being applied to each part. The mean was corrected by a weighting function while the perturbation was corrected by the self-organizing maps method. The results with correction agree well with the observed pattern compared to those without correction, improving the spatial and temporal correlations as well as the RMSE. In addition, they represented detailed spatial features of temperature including topographic signals, which cannot be expressed properly by gridded observation. Through comparison with in-situ observation with gridded values after objective analysis, it was found that the detailed structure correctly reflected topographically diverse signals that could not be derived from limited observation data. We expect that the correction method developed in this study can be effectively used for the analyses and projections of climate downscaled by using region climate models. Acknowledgements This work was carried out with the support of Korea Meteorological Administration Research and Development Program under Grant CATER 2012-3083 and Rural Development Administration Cooperative Research Program for Agriculture Science and Technology Development under Grant Project No. PJ009353, Republic of Korea. Reference Ahn, J.-B., Lee, J.-L., and Im, E.-S., 2012: The reproducibility of surface air temperature over South Korea using dynamical downscaling and statistical correction, J. Meteor. Soc. Japan, 90, 493-507, doi: 10.2151/jmsj.2012-404

Ahn, J.; Lee, J.; Shim, K.; Kim, Y.

2013-12-01

161

Dynamics of rotating triple systems: statistical escape theory versus numerical simulations

NASA Astrophysics Data System (ADS)

Dynamical evolution of 120000 equal-mass rotating triple systems is investigated. The system rotation is described by the parameter w=-L20E0/G2m50, where G is the gravitational constant, m0 is the mass of a body, and L0 and E0 are the angular momentum and the total energy of the triple system, respectively. We consider the values of w= 0.005, 0.1, 1, 2, 4 and 6. For each w, 20000 triple systems are studied. The initial coordinates and velocities of the components are randomly chosen. The initial data are chosen in two different ways: the first one assumes a hierarchical structure initially and the second one does not. The evolution of each triple system is calculated until either the escape of one of the bodies occurs or the time exceeds 1000 mean crossing times of the system. The orbital parameters of the final binary and the escaper are recorded for each run. We compare the results of numerical simulations and predictions of a statistical escape theory. The statistical theory is based on the assumption of ergodicity, that is, the only information on the initial conditions remaining at the time of the escape of the third body is contained in the conserved total energy, total angular momentum and the mass values. The distributions of various quantities are derived from the allowable phase-space volumes. The distribution of binary energy agrees with earlier results by Heggie, with the angular momentum dependence of Mikkola & Valtonen being added. The eccentricities are distributed in general accordance with Monaghan's work, while the triple systems break up like in radioactive decay, as was previously found by Valtonen & Aarseth. The escape directions are preferentially perpendicular to the total angular momentum vector; the more so, the greater the angular momentum. The escape-angle distributions are derived from the statistical theory and are found to be in agreement with the numerical data. The relative orientations and magnitudes of the binary and third-body angular momenta are also explained based on the statistical theory.

Valtonen, M.; Mylläri, A.; Orlov, V.; Rubinov, A.

2005-11-01

162

NASA Astrophysics Data System (ADS)

Dynamical complexity detection for output time series of complex systems is one of the foremost problems in physics, biology, engineering, and economic sciences. Especially in geomagnetism and magnetospheric physics, accurate detection of the dissimilarity between normal and abnormal states (e.g. pre-storm activity and magnetic storms) can vastly improve geomagnetic field modelling as well as space weather forecasting, respectively. Nonextensive statistical mechanics through Tsallis entropy provides a solid theoretical basis for describing and analyzing complex systems out of equilibrium, particularly systems exhibiting long-range correlations or fractal properties. Entropy measures (e.g., Tsallis entropy, Shannon entropy, block entropy, Kolmogorov entropy, T-complexity, and approximate entropy) have been proven effectively applicable for the investigation of dynamical complexity in Dst time series. It has been demonstrated that as a magnetic storm approaches, there is clear evidence of significantly lower complexity in the magnetosphere. The observed higher degree of organization of the system agrees with results previously inferred from fractal analysis via estimates of the Hurst exponent based on wavelet transform. This convergence between entropies and linear analyses provides a more reliable detection of the transition from the quiet time to the storm time magnetosphere, thus showing evidence that the occurrence of an intense magnetic storm is imminent. Moreover, based on the general behavior of complex system dynamics it has been recently found that Dst time series exhibit discrete scale invariance which in turn leads to log-periodic corrections to scaling that decorate the pure power law. The latter can be used for the determination of the time of occurrence of an approaching magnetic storm.

Balasis, G.

2012-04-01

163

We tested the natural combination of surrogate data analysis with the ApEn\\u000aregularity statistic developed by Pincus [Proc. Natl. Acad. Sci. USA 88 (1991)\\u000a2297] by applying it to some popular models of nonlinear dynamics and publicly\\u000aavailable experimental time series. We found that this easily implemented\\u000acombination provided a useful method for discriminating signals governed by\\u000anonlinear dynamics from

Randall A. LaViolette; Charles R. Tolle; Timothy R. McJunkin; Daphne L. Stoner

2004-01-01

164

The linked ArcView 2.1 and XGobi environment—GIS, dynamic statistical graphics, and spatial data

This paper reports on research into interactive, dynamic statistical graphics (DSG) applied to spatial data maintained within a geo- graphic information system (GIS). We developed a bidirectional link between ArcView 2.1 , a GIS, and XGobi, a DSG program. Multivariate data, collected at geographic locations, is passed from ArcView to XGobi and can be dynamically analyzed. The relation between the

Jiirgen Symanzik; James J. Majure; Dianne Cook

1996-01-01

165

Intramolecular Distances and Dynamics from the Combined Photon Statistics of Single-Molecule FRET resonance energy transfer (FRET) and photo- induced electron transfer (PET) have developed into versatile are frequently used as a donor and acceptor for single-molecule FRET, are also suitable as PET probes

Schuler, Ben

166

We investigate the effect of electric synapses (gap junctions) on collective neuronal dynamics and spike statistics in a conductance-based Integrate-and-Fire neural network, driven by a Brownian noise, where conductances depend upon spike history. We compute explicitly the time evolution operator and show that, given the spike-history of the network and the membrane potentials at a given time, the further dynamical evolution can be written in a closed form. We show that spike train statistics is described by a Gibbs distribution whose potential can be approximated with an explicit formula, when the noise is weak. This potential form encompasses existing models for spike trains statistics analysis such as maximum entropy models or Generalized Linear Models (GLM). We also discuss the different types of correlations: those induced by a shared stimulus and those induced by neurons interactions.

Rodrigo Cofré; Bruno Cessac

2012-12-14

167

Technology Transfer Automated Retrieval System (TEKTRAN)

QseA and SdiA are two of several transcriptional regulators that regulate virulence gene expression of enterohemorrhagic Escherichia coli (EHEC) O157:H7 via quorum sensing (QS). QseA regulates the expression of the locus of enterocyte effacement (LEE). LEE encodes for a type III secretion (T3S) sys...

168

ERIC Educational Resources Information Center

During a 2-year period (1970, 1971) SDI (Selective Dissemination of Information) search profiles were written for 353 biologists and other research workers with a need for biological information in academic, industrial, and government research institutions. At the beginning of the experiment a questionnaire and interview survey was made of the…

Leggate, P.; And Others

169

ERIC Educational Resources Information Center

A selective dissemination of information service based on computer scanning of Nuclear Science Abstracts tapes has operated at the Atomic Energy Research Establishment, Harwell, England since October, 1968. The performance of the mechanized SDI service has been compared with that of the pre-existing current awareness service which is based on…

Olive, G.; And Others

170

Statistics of initial density perturbations in heavy ion collisions and their fluid dynamic response

An interesting opportunity to determine thermodynamic and transport properties in more detail is to identify generic statistical properties of initial density perturbations. Here we study event-by-event fluctuations in terms of correlation functions for two models that can be solved analytically. The first assumes Gaussian fluctuations around a distribution that is fixed by the collision geometry but leads to non-Gaussian features after averaging over the reaction plane orientation at non-zero impact parameter. In this context, we derive a three-parameter extension of the commonly used Bessel-Gaussian event-by-event distribution of harmonic flow coefficients. Secondly, we study a model of N independent point sources for which connected n-point correlation functions of initial perturbations scale like 1/N^(n-1). This scaling is violated for non-central collisions in a way that can be characterized by its impact parameter dependence. We discuss to what extent these are generic properties that can be expected to hold for any model of initial conditions, and how this can improve the fluid dynamical analysis of heavy ion collisions.

Stefan Floerchinger; Urs Achim Wiedemann

2014-08-28

171

Dynamical and Statistical Fragment Production in Heavy-Ion Collisions at Intermediate Energies

NASA Astrophysics Data System (ADS)

A large set of experimental data was analyzed in terms of characteristic signatures of different interaction as well as product emission scenarios. The analysis confirms that the reaction cross-section appears still dominated by dissipative binary reactions involving the survival of well-defined projectile- and target-like fragments. Consistent with such a "gentle" collision scenario are the Galilei-invariant velocity distributions of charged products featuring statistical emission from two fully accelerated projectile- and target-like fragments. On the other hand, the Galilei-invariant velocity plots reveal the presence of a third effective emission source with velocity intermediate between the velocities of projectile- and target-like fragments. Fragments emitted from the intermediate-velocity source appear to be produced dynamically in the overlap zone of the projectile and target nuclei. The experimental multidimensional joint distributions of neutrons and charged reaction products were found to exhibit several different types of prominent correlation patterns. It makes them a useful tool for probing reactions scenarios, different from the traditional approach of interpreting inclusive yields of individual reaction products.

Gawlikowicz, W.

2009-06-01

172

Statistics of initial density perturbations in heavy ion collisions and their fluid dynamic response

NASA Astrophysics Data System (ADS)

An interesting opportunity to determine thermodynamic and transport properties in more detail is to identify generic statistical properties of initial density perturbations. Here we study event-by-event fluctuations in terms of correlation functions for two models that can be solved analytically. The first assumes Gaussian fluctuations around a distribution that is fixed by the collision geometry but leads to non-Gaussian features after averaging over the reaction plane orientation at non-zero impact parameter. In this context, we derive a three-parameter extension of the commonly used Bessel-Gaussian event-by-event distribution of harmonic flow coefficients. Secondly, we study a model of N independent point sources for which connected n-point correlation functions of initial perturbations scale like 1 /N n-1. This scaling is violated for non-central collisions in a way that can be characterized by its impact parameter dependence. We discuss to what extent these are generic properties that can be expected to hold for any model of initial conditions, and how this can improve the fluid dynamical analysis of heavy ion collisions.

Floerchinger, Stefan; Wiedemann, Urs Achim

2014-08-01

173

Background Tropospheric Aerosols: Incorporation within a statistical-dynamical climate model

NASA Astrophysics Data System (ADS)

To evaluate the possible influence of natural background tropospheric aerosols upon the earth's present climate, we have incorporated aerosol radiation models for continental and maritime aerosols into the Lawrence Livermore National Laboratory statistical-dynamical climate model. The model results suggest that background tropospheric aerosols produce 3°-4°C global surface cooling, with maximum cooling occurring at high latitudes, results which are essentially consistent with an energy balance climate model study by Coakley et al. (1983). To specifically delineate effects caused directly by the aerosols, as opposed to indirect effects resulting from aerosol-induced climate change, a second climate perturbation was considered that consisted of reducing the solar constant so as to give exactly the same initial reduction in surface-atmosphere solar absorption as for the inclusion of tropospheric aerosols. These separate climate perturbations produced nearly identical climate feedback effects, together with similar changes in atmospheric stability and hydrological cycle, despite the fact that the two perturbations have quite different latitudinal and vertical distributions. This finding is consistent with a general circulation model study by Manabe and Wetherald (1980) concerning perturbations of both atmospheric CO2 and the solar constant. A related conclusion is that the model's climate response to tropospheric aerosols is insensitive to the manner in which the aerosols are vertically distributed.

Potter, Gerald L.; Cess, Robert D.

1984-10-01

174

Dynamical and statistical behavior of discrete combustion waves: A theoretical and numerical study

NASA Astrophysics Data System (ADS)

We present a detailed theoretical and numerical study of combustion waves in a discrete one-dimensional disordered system. The distances between neighboring reaction cells were modeled with a gamma distribution. The results show that the random structure of the microheterogeneous system plays a crucial role in the dynamical and statistical behavior of the system. This is a consequence of the nonlinear interaction of the random structure of the system with the thermal wave. An analysis of the experimental data on the combustion of a gasless system (Ti + xSi) and a wide range of thermite systems was performed in view of the developed model. We have shown that the burning rate of the powder system sensitively depends on its internal structure. The present model allows for reproducing theoretically the experimental data for a wide range of pyrotechnic mixtures. We show that Arrhenius’ macrokinetics at combustion of disperse systems can take place even in the absence of Arrhenius’ microkinetics; it can have a purely thermal nature and be related to their heterogeneity and to the existence of threshold temperature. It is also observed that the combustion of disperse systems always occurs in the microheterogeneous mode according to the relay-race mechanism.

Bharath, Naine Tarun; Rashkovskiy, Sergey A.; Tewari, Surya P.; Gundawar, Manoj Kumar

2013-04-01

175

Sensitivity properties of a biosphere model based on BATS and a statistical-dynamical climate model

NASA Technical Reports Server (NTRS)

A biosphere model based on the Biosphere-Atmosphere Transfer Scheme (BATS) and the Saltzman-Vernekar (SV) statistical-dynamical climate model is developed. Some equations of BATS are adopted either intact or with modifications, some are conceptually modified, and still others are replaced with equations of the SV model. The model is designed so that it can be run independently as long as the parameters related to the physiology and physiognomy of the vegetation, the atmospheric conditions, solar radiation, and soil conditions are given. With this stand-alone biosphere model, a series of sensitivity investigations, particularly the model sensitivity to fractional area of vegetation cover, soil surface water availability, and solar radiation for different types of vegetation, were conducted as a first step. These numerical experiments indicate that the presence of a vegetation cover greatly enhances the exchanges of momentum, water vapor, and energy between the atmosphere and the surface of the earth. An interesting result is that a dense and thick vegetation cover tends to serve as an environment conditioner or, more specifically, a thermostat and a humidistat, since the soil surface temperature, foliage temperature, and temperature and vapor pressure of air within the foliage are practically insensitive to variation of soil surface water availability and even solar radiation within a wide range. An attempt is also made to simulate the gradual deterioration of environment accompanying gradual degradation of a tropical forest to grasslands. Comparison with field data shows that this model can realistically simulate the land surface processes involving biospheric variations.

Zhang, Taiping

1994-01-01

176

at the low energy regime by means of a statistical quantum method TomÃ¡s GonzÃ¡lez-Lezana,1,a) Pascal Honvault of a statistical quantum mechanical (SQM) method. Reaction probabilities and integral cross sections (ICSs) betweenDynamics of the D+ + H2 HD + H+ reaction at the low energy regime by means of a statistical

Honvault, Pascal

177

Neurons in the auditory system respond to recent stimulus-level history by adapting their response functions according to the statistics of the stimulus, partially alleviating the so-called “dynamic-range problem.” However, the mechanism and source of this adaptation along the auditory pathway remain unknown. Inclusion of power-law dynamics in a phenomenological model of the inner hair cell (IHC)- auditory nerve (AN) synapse successfully explained neural adaptation to sound-level statistics, including the time course of adaptation of the mean firing rate and changes in the dynamic range observed in AN responses. A direct comparison between model responses to a dynamic stimulus and to an “inversely-gated” static background suggested that AN dynamic-range adaptation largely results from the adaptation produced by the response history. These results support the hypothesis that the potential mechanism underlying the dynamic-range adaptation observed at the level of the auditory nerve is located peripheral to the spike generation mechanism and central to the IHC receptor potential. PMID:20685981

Zilany, Muhammad S. A.; Carney, Laurel H.

2010-01-01

178

Statistical Analysis of Ground Motion from Steady State Dynamic Rupture Pulses

NASA Astrophysics Data System (ADS)

Two-dimensional steady state dynamic rupture model is used to perform statistical analysis on both synthetic and field data. Given the medium and acquisition parameters, this model relates the fault-parallel and fault-perpendicular ground motion to the slipping zone length L, the slip weakening zone length R, total locked-in slip ? and rupture velocity V. Moreover, fault rotation and static time shift parameters are added to account for possible acquisition errors. The model is examined for sub-shear rupture velocities only. Although relatively simple, this model has several attractive features such as computational efficiency and limited number of parameters, which makes sophisticated and comprehensive statistical analysis feasible. Our main goal is to infer fracture energies G for larger earthquakes and analyzing the sensitivity of these energies to the model parameters. First, we create a synthetic dataset using the steady state model to analyze the objective function behavior around the correct solution. We perturb each parameter independently to estimate the convexity of the parameters as well as the data sensitivity to the parameters. Then, we estimate the correlation matrix between the parameters using the analytical solution. The correlation matrix indicates that the rupture velocity, locked-in slip and fracture energy are weakly correlated with the other parameters for both the fault-parallel and fault-perpendicular data. Next, we implement a Markov chain Monte Carlo algorithm to the data to obtain the probability distribution of the objective function. We analyze both the marginal and the complete probability distributions. The results indicate that the parameters widely vary in terms of sensitivity and resolution with respect to the fracture energy. Nonetheless, the fracture energy can be estimated with reasonable accuracy. Afterwards, we repeat our analysis using field datasets. The resulting probability densities have maximum likelihoods for fracture energy around 1-4 MJ/m/m. The analysis was done using single-receiver data. Further analysis is needed for using multi-receiver data, which can potentially increase the accuracy and robustness of the method.

Almomin, A. A.; Dunham, E. M.

2013-12-01

179

Hydrologic Implications of Dynamical and Statistical Approaches to Downscaling Climate Model Outputs

Six approaches for downscaling climate model outputs for use in hydrologic simulation were evaluated, with particular emphasis on each method's ability to produce precipitation and other variables used to drive a macroscale hydrology model applied at much higher spatial resolution than the climate model. Comparisons were made on the basis of a twenty-year retrospective (1975–1995) climate simulation produced by the NCAR-DOE Parallel Climate Model (PCM), and the implications of the comparison for a future (2040–2060) PCM climate scenario were also explored. The six approaches were made up of three relatively simple statistical downscaling methods – linear interpolation (LI), spatial disaggregation (SD), and bias-correction and spatial disaggregation (BCSD) – each applied to both PCM output directly (at T42 spatial resolution), and after dynamical downscaling via a Regional Climate Model (RCM – at ½-degree spatial resolution), for downscaling the climate model outputs to the ?-degree spatial resolution of the hydrological model. For the retrospective climate simulation, results were compared to an observed gridded climatology of temperature and precipitation, and gridded hydrologic variables resulting from forcing the hydrologic model with observations. The most significant findings are that the BCSD method was successful in reproducing the main features of the observed hydrometeorology from the retrospective climate simulation, when applied to both PCM and RCM outputs. Linear interpolation produced better results using RCM output than PCM output, but both methods (PCM-LI and RCM-LI) lead to unacceptably biased hydrologic simulations. Spatial disaggregation of the PCM output produced results similar to those achieved with the RCM interpolated output; nonetheless, neither PCM nor RCM output was useful for hydrologic simulation purposes without a bias-correction step. For the future climate scenario, only the BCSD-method (using PCM or RCM) was able to produce hydrologically plausible results. With the BCSD method, the RCM-derived hydrology was more sensitive to climate change than the PCM-derived hydrology.

Wood, Andrew W.; Leung, Lai R.; Sridhar, V.; Lettenmaier, D. P.

2004-01-01

180

Sensitivity properties of a biosphere model based on BATS and a statistical-dynamical climate model

A biosphere model based on the Biosphere-Atmosphere Transfer Scheme (BATS) and the Saltzman-Vernekar (SV) statistical-dynamical climate model is developed. Some equations of BATS are adopted either intact or with modifications, some are conceptually modified, and still others are replaced with equations of the SV model. The model is designed so that it can be run independently as long as the parameters related to the physiology and physiognomy of the vegetation, the atmospheric conditions, solar radiation, and soil conditions are given. With this stand-alone biosphere model, a series of sensitivity investigations, particularly the model sensitivity to fractional area of vegetation cover, soil surface water availability, and solar radiation for different types of vegetation, were conducted as a first step. These numerical experiments indicate that the presence of a vegetation cover greatly enhances the exchanges of momentum, water vapor, and energy between the atmosphere and the surface of the earth. An interesting result is that a dense and thick vegetation cover tends to serve as an environment conditioner or, more specifically, a thermostat and a humidistat, since the soil surface temperature, foliage temperature, and temperature and vapor pressure of air within the foliage are practically insensitive to variation of soil surface water availability and even solar radiation within a wide range. An attempt is also made to simulate the gradual deterioration of environment accompanying gradual degradation of a tropical forest to grasslands. Comparison with field data shows that this model can realistically simulate the land surface processes involving biospheric variations. 46 refs., 10 figs., 6 tabs.

Zhang, T. (Yale Univ., New Haven, CT (United States))

1994-06-01

181

The zonally averaged response of the Global Change Research Center two-dimensional (2-D) statistical dynamical climate model (GCRC 2-D SDCM) to a doubling of atmospheric carbon dioxide (350 parts per million by volume (ppmv) to 700 ppmv) is reported. The model solves the two-dimensional primitive equations in finite difference form (mass continuity, Newton's second law, and the first law of thermodynamics)

R. M. MacKay; M. A. K. Khalil

1995-01-01

182

This paper compares six statistical downscaling models (SDMs) and three regional climate models (RCMs) in their ability to downscale daily precipitation statistics in a region of complex topography. The six SDMs include regression methods, weather typing methods, a conditional weather generator, and a bias correction and spatial disaggregation approach. The comparison is carried out over the European Alps for current

J. Schmidli; C. M. Goodess; C. Frei; M. R. Haylock; Y. Hundecha; J. Ribalaygua; T. Schmith

2007-01-01

183

A dynamical and statistical understanding of the North Atlantic Oscillation and annular modes

NASA Astrophysics Data System (ADS)

We present a hierarchy of idealized models of the North Atlantic Oscillation (NAO) and Annular Modes, the dominant patterns of intraseasonal variability in the extratropical atmosphere. The models isolate the dynamics governing the spatial and temporal structure of the patterns, and provide a framework for interpreting measures of the variability produced by Empirical Orthogonal Function and teleconnection analysis. A barotropic model on the sphere indicates that the patterns are a consequence of the chaotic "stirring" of the atmosphere by baroclinic eddies. Such stirring, represented by a simple random forcing, leads to variability of the zonal flow via variability in the eddy momentum flux convergence. Zonal structure of the forcing dictates zonal structure of the variability, suggesting that the NAO follows from the localized synoptic variability of the North Atlantic storm track. Intraseasonal variability is more persistent than the eddies that force it, as integration of eddy fluxes by the equations of motion strengthens power at lower frequencies. The patterns' spatial structure is investigated with analytic, purely stochastic models of the zonally averaged zonal wind and surface pressure. The meridional structure stems from geometric constraints and the conservation of mass and zonal momentum. A two-dimensional extension of the model reveals that symmetry of the statistics, not necessarily the motions, is sufficient for the existence of an annular pattern, explaining the presence of annular modes in systems lacking hemispherically coherent motions. Conclusions from the simpler models are verified with a dry, primitive equation general circulation model. Annular mode and NAO-like patterns are found by varying the zonal structure of synoptic variability with idealized topography and heating anomalies approximating land-sea contrast. The NAO arises from the confluence of topographic and thermal forcing, and is best understood in terms of the eddy life cycle. A parameter sensitive coupling between eddies and the large-scale flow extends the persistence and zonal coherence of the intraseasonal variability. The mainly barotropic circulation anomalies influence the baroclinicity by shifting the critical latitudes, thus shaping the eddy momentum fluxes. Sensitivity of the coupling to asymmetric forcing suggest that localized NAO-like variability is more dominant when eddy-mean flow interactions are weakened.

Gerber, Edwin Paul

184

NASA Astrophysics Data System (ADS)

We use models for mean and extreme values of total column ozone on spatial scales to analyze "fingerprints" of atmospheric dynamics and chemistry on long-term ozone changes at northern and southern mid-latitudes. The r-largest order statistics method is used for pointwise analysis of extreme events in low and high total ozone (termed ELOs and EHOs, respectively). For the corresponding mean value analysis a pointwise autoregressive moving average model (ARMA) is used. The statistical models include important atmospheric covariates to describe the dynamical and chemical state of the atmosphere: the solar cycle, the Quasi-Biennial Oscillation (QBO), ozone depleting substances (ODS) in terms of equivalent effective stratospheric chlorine (EESC), the North Atlantic Oscillation (NAO), the Antarctic Oscillation (AAO), the El~Niño/Southern Oscillation (ENSO), and aerosol load after the volcanic eruptions of El Chichón and Mt. Pinatubo. The influence of the individual covariates on mean and extreme levels in total column ozone is derived on a grid cell basis. The results show that "fingerprints", i.e., significant influence, of dynamical and chemical features are captured in both the "bulk" and the tails of the ozone distribution, respectively described by means and EHOs/ELOs. While results for the solar cycle, QBO and EESC are in good agreement with findings of earlier studies, unprecedented spatial fingerprints are retrieved for the dynamical covariates.

Frossard, L.; Rieder, H. E.; Ribatet, M.; Staehelin, J.; Maeder, J. A.; Di Rocco, S.; Davison, A. C.; Peter, T.

2012-05-01

185

NASA Astrophysics Data System (ADS)

Statistical analysis of the plastic deformation steps and fracture of polycrystalline ice has been performed. It is established that an increase in deformation leads to gradual evolution of the statistics of amplitudes of mesoscopic deformation jumps from random (with a Poisson distribution of dislocation avalanche amplitudes) to “critical” (with a power-law distribution), which indicates occurrence of long-range correlations of the dislocation mesodynamics of deformed polycrystalline ice. The state of self-organized criticality at subcritical ice fracture has been revealed from the power-law statistics of the amplitudes of electric pulses and pauses between them, flicker-noise structure, and almost monofractal character of signals.

Shibkov, A. A.; Kazakov, A. A.

2009-03-01

186

NASA Astrophysics Data System (ADS)

We report on early science results from the newly-commissioned Magellan AO (MagAO) system's VisAO camera in Simultaneous Differential Imaging (SDI) mode. The MagAO Adaptive Secondary Mirror's high actuator pitch allow us to achieve AO correction into the visible wavelength regime, and VisAO is the first visible light science camera behind a large (d>6m) telescope AO system. This opens up an interesting new region of parameter space to high contrast, high spatial resolution science. As a natural guide star system, MagAO is optimized for circumstellar science, including both point source detection and high resolution imaging of circumstellar disks. Early SDI science results include the first circumstellar disk imaged in silhouette from the ground, high-resolution images of a binary propylid in Orion and high contrast images of an accreting point source at small separation.

Follette, Kate; Close, Laird; Wu, Ya-Lin; Males, Jared; Morzinski, Katie; Kopon, Derek

2013-07-01

187

Observation and Nature of Non-statistical Dynamic Effects in Ordinary Organic Reactions

such as unusual isotope effects due to extensive recrossing. Preliminary results for the organocatalytic reaction show an intramolecular KIE close to unity that cannot be reconciled with statistical theories. This is in contrast with Lewis-acid catalyzed...

Quijano, Larisa Mae Mangaliman 1984-

2012-10-17

188

A prerequisite of a successful statistical downscaling is that large-scale predictors simulated by the General Circulation\\u000a Model (GCM) must be realistic. It is assumed here that features smaller than the GCM resolution are important in determining\\u000a the realism of the large-scale predictors. It is tested whether a three-step method can improve conventional one-step statistical\\u000a downscaling. The method uses predictors that

Cecilia Hellström; Deliang Chen

2003-01-01

189

Dynamics of the environments of complex systems such as biomolecules, polar solvents, and glass plays an important role in controlling electron transfer reactions. The kinetics is determined by the nature of a complex multidimensional landscape. By quantifying the mean and high-order statistics of the first-passage time and the associated ratios, the dynamics in electron transfer reactions controlled by the environments can be revealed. We consider real experimental conditions with finite observation time windows. At high temperatures, exponential kinetics is observed and there are multiple kinetic paths leading to the product state. At and below an intermediate temperature, nonexponential kinetics starts to appear, revealing the nature of the distribution of local traps on the landscape. Discrete kinetic paths emerge. At very low temperatures, nonexponential kinetics continues to be observed. We point out that the size of the observational time window is crucial in revealing the intrinsic nature of the real kinetics. The mean first-passage time is defined as a characteristic time. Only when the observational time window is significantly larger than this characteristic time does one have the opportunity to collect enough statistics to capture rare statistical fluctuations and characterize the kinetics accurately. PMID:19071925

Paula, Luciana C; Wang, Jin; Leite, Vitor B P

2008-12-14

190

Dynamics of the environments of complex systems such as biomolecules, polar solvents, and glass plays an important role in controlling electron transfer reactions. The kinetics is determined by the nature of a complex multidimensional landscape. By quantifying the mean and high-order statistics of the first-passage time and the associated ratios, the dynamics in electron transfer reactions controlled by the environments can be revealed. We consider real experimental conditions with finite observation time windows. At high temperatures, exponential kinetics is observed and there are multiple kinetic paths leading to the product state. At and below an intermediate temperature, nonexponential kinetics starts to appear, revealing the nature of the distribution of local traps on the landscape. Discrete kinetic paths emerge. At very low temperatures, nonexponential kinetics continues to be observed. We point out that the size of the observational time window is crucial in revealing the intrinsic nature of the real kinetics. The mean first-passage time is defined as a characteristic time. Only when the observational time window is significantly larger than this characteristic time does one have the opportunity to collect enough statistics to capture rare statistical fluctuations and characterize the kinetics accurately.

Paula, Luciana C. [Departamento de Fisica, Instituto de Biociencias Letras e Ciencias Exatas, Universidade Estadual Paulista, Sao Jose do Rio Preto, Sao Paulo 15054-000 (Brazil); Departamento de Estudos Basicos e Instrumentais, Universidade Estadual do Sudoeste da Bahia, Itapetinga, Bahia 45700-000 (Brazil); Wang Jin [Department of Chemistry, Physics and Applied Mathematics, State University of New York at Stony Brook, Stony Brook, New York 11794-3800 (United States); State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry of Chinese Academy of Sciences, Changchun 130022 (China); Leite, Vitor B. P. [Departamento de Fisica, Instituto de Biociencias Letras e Ciencias Exatas, Universidade Estadual Paulista, Sao Jose do Rio Preto, Sao Paulo 15054-000 (Brazil)

2008-12-14

191

NASA Astrophysics Data System (ADS)

We use statistical models for mean and extreme values of total column ozone to analyze "fingerprints" of atmospheric dynamics and chemistry on long-term ozone changes at northern and southern mid-latitudes on grid cell basis. At each grid cell, the r-largest order statistics method is used for the analysis of extreme events in low and high total ozone (termed ELOs and EHOs, respectively), and an autoregressive moving average (ARMA) model is used for the corresponding mean value analysis. In order to describe the dynamical and chemical state of the atmosphere, the statistical models include important atmospheric covariates: the solar cycle, the Quasi-Biennial Oscillation (QBO), ozone depleting substances (ODS) in terms of equivalent effective stratospheric chlorine (EESC), the North Atlantic Oscillation (NAO), the Antarctic Oscillation (AAO), the El Niño/Southern Oscillation (ENSO), and aerosol load after the volcanic eruptions of El Chichón and Mt. Pinatubo. The influence of the individual covariates on mean and extreme levels in total column ozone is derived on a grid cell basis. The results show that "fingerprints", i.e., significant influence, of dynamical and chemical features are captured in both the "bulk" and the tails of the statistical distribution of ozone, respectively described by mean values and EHOs/ELOs. While results for the solar cycle, QBO, and EESC are in good agreement with findings of earlier studies, unprecedented spatial fingerprints are retrieved for the dynamical covariates. Column ozone is enhanced over Labrador/Greenland, the North Atlantic sector and over the Norwegian Sea, but is reduced over Europe, Russia and the Eastern United States during the positive NAO phase, and vice-versa during the negative phase. The NAO's southern counterpart, the AAO, strongly influences column ozone at lower southern mid-latitudes, including the southern parts of South America and the Antarctic Peninsula, and the central southern mid-latitudes. Results for both NAO and AAO confirm the importance of atmospheric dynamics for ozone variability and changes from local/regional to global scales.

Frossard, L.; Rieder, H. E.; Ribatet, M.; Staehelin, J.; Maeder, J. A.; Di Rocco, S.; Davison, A. C.; Peter, T.

2013-01-01

192

Quiet-time statistics: A tool to probe the dynamics of self-organized-criticality systems from on the analysis of the statistics of the lapses of time between activity bursts or quiet times. The case to cease. There is always a finite even if some- times negligible probability of avalanche overlapping

MartÃn-SolÃs, JosÃ© RamÃ³n

193

NASA Astrophysics Data System (ADS)

The most successful approaches to both machine target recognition and robot arm manipulation have been those where tasks are completely pre-specified. In such systems there is little room for deviations in robot path motion or target location and orientation. A novel approach to robotic implementation such as spaceborne assembly of SDI platforms are too difficult for existing robots because random occurrences and large numbers of external variables preclude the complete specification of tasks off-line. The proposed system has strong adaptability due to the following innovations: Registered video and range laser radar sensing (i.e., a one-to-one correspondence between visual and range data). This allows fast, accurate 3D target recognition as part of an autonomous CAD model based recognition system for Phase 2, or as input to teleoperator control in Phase 1. Closed loop range and video feedback for grasper guidance using the pose matching concept where target and grasper are both in the field of view, and CAD derived track points are used for position and orientation error signals.

Frey, Randy W.; Bohlin, John A.

1990-02-01

194

A dynamical equation for a maser with non-poissonian injection statistics

A derivation of the coarse grained dynamical equation for a maser with periodic injection of atoms suggested by Briegel and Englert [Phys.Rev.A. {\\bf 52}, 2361 (1995)] from the microscopic masterequation is presented.

Michael Fleischhauer

2014-10-12

195

A simple statistical-dynamical downscaling scheme based on weather types and conditional resampling

A multivariate statistical downscaling methodology is implemented to generate local precipitation and temperature series at different sites based on the results from a variable resolution general circulation model. It starts from regional climate properties to establish discriminating weather types for the chosen local variable, precipitation in this case. Intratype variations of the relevant forcing parameters are then taken into account

J. Boé; L. Terray; F. Habets; E. Martin

2006-01-01

196

1. NTRODUCTION Analyses performed for the US National Assessment require accurate projections of climate at scales below those resolved by global General Circulation Models (GCMs). Two techniques have been developed that counter this deficiency: semi- empirical (statistical) downscaling (SDS) of GCM outputs, and regional climate models (RCMs) nested within a GCM. To date, few studies have compared SDS and RCM

W. J. Gutowski; R. Wilby; L. E. Hay; C. J. Anderson; R. W. Arritt; M. P. Clark; G. H. Leavesley; Z. Pan; R. Silva; E. S. Takle

197

The Use of Advanced Statistical Concepts and Analysis to Improve Nonlinear Dynamic Glucose Modeling

Type 2 diabetes is one of the greatest burdens on the health care industry today. This condition is characterized by poor control of blood glucose concentration (BGC). In order to help those afflicted with type 2 diabetes better control their BGC, the goal of this research is to develop a device that can noninvasively measure BGC. There are several statistical

Lucas Beverlin

2011-01-01

198

Static Numbers to Dynamic Statistics: Designing a Policy-Friendly Social Policy Indicator Framework

ERIC Educational Resources Information Center

In line with the economic crisis and rapid socio-demographic changes, the interest in "social" and "well-being" indicators has been revived. Social indicator movements of the 1960s resulted in the establishment of social indicator statistical frameworks; that legacy has remained intact in many national governments and international organisations.…

Ahn, Sang-Hoon; Choi, Young Jun; Kim, Young-Mi

2012-01-01

199

NASA Astrophysics Data System (ADS)

The statistical properties of over 300 different proxy records of the last two thousand years derived from the PAGES 2k database years are stochastically analysed. Analyses include estimation of their first four moments and their autocorrelation functions (ACF), as well as the determination of the presence of Hurst-Kolmogorov behaviour (known also as long term persistence). The data are investigated in groups according to their proxy type and location, while their statistical properties are also compared to those of the final temperature reconstructions. Acknowledgement: This research is conducted within the frame of the undergraduate course "Stochastic Methods in Water Resources" of the National Technical University of Athens (NTUA). The School of Civil Engineering of NTUA provided moral support for the participation of the students in the Assembly.

Koukas, Ioannis; Koukoravas, Vasilis; Mantesi, Konstantina; Sakellari, Katerina; Xanthopoulou, Themis-Demetra; Zarkadoulas, Akis; Markonis, Yannis; Papalexiou, Simon Michael; Koutsoyiannis, Demetris

2014-05-01

200

NASA Astrophysics Data System (ADS)

We have measured the fluctuations in the phase of ultrasound transmitted through a very strongly scattering, fluidized suspension of 1-mm-diameter glass beads in a glycerol/water solution. Through the use of the diffusion approximation for wave propagation, and by assuming circular Gaussian statistics for the field fluctuations, we are able to model the statistics of the phase, and relate the phase difference probability distribution to the relative motion of the scattering particles. The phase distributions are in excellent agreement with our model, and the measurements of the particle motions thereby derived are in good agreement with our results obtained from the temporal field autocorrelation function in Diffusing Acoustic Wave Spectroscopy [1]. [1] M. L. Cowan, J. H. Page and D. A. Weitz, Phys. Rev. Lett. 85, 453 (2000).

Page, J. H.; Cowan, M. L.; van Tiggelen, B. A.

2001-03-01

201

Nonequilibrium statistical mechanics of a two-temperature Ising ring with conserved dynamics

NASA Astrophysics Data System (ADS)

The statistical mechanics of a one-dimensional Ising model in thermal equilibrium is well-established, textbook material. Yet, when driven far from equilibrium by coupling two sectors to two baths at different temperatures, it exhibits remarkable phenomena, including an unexpected "freezing by heating." These phenomena are explored through systematic numerical simulations. Our study reveals complicated relaxation processes as well as a crossover between two very different steady-state regimes.

Borchers, Nicholas; Pleimling, Michel; Zia, R. K. P.

2014-12-01

202

Statistical programs utilizing dynamic allocation of memory on the CDC 6400

Statistical routines written for general use often require large data storage arrays. A program using three n x n arrays,\\u000a for instance, would require 30,000 words of memory for 100 variables. Usually the number of variables in any analysis is less\\u000a than the maximum number of variables dimensioned in the program. This generally results in a number of unused data

Paul L. Derby

1974-01-01

203

The Omegabar\\/Omega ratio originating from string decays is predicted to be larger than unity in proton-proton interactions at SPS energies ( Elab = 160 GeV). The antiomega dominance increases with decreasing beam energy. This surprising behavior is caused by the combinatorics of quark-antiquark production in small and low-mass strings. Since this behavior is not found in a statistical description of

M. Bleicher; F. M. Liu; A. Keränen; J. Aichelin; S. A. Bass; F. Becattini; K. Redlich; K. Werner

2002-01-01

204

Dynamic Range Adaptation to Spectral Stimulus Statistics in Human Auditory Cortex

Classically, neural adaptation refers to a reduction in response magnitude by sustained stimulation. In human electroencephalography (EEG), neural adaptation has been measured, for example, as frequency-specific response decrease by previous stimulation. Only recently and mainly based on animal studies, it has been suggested that statistical properties in the stimulation lead to adjustments of neural sensitivity and affect neural response adaptation. However, it is thus far unresolved which statistical parameters in the acoustic stimulation spectrum affect frequency-specific neural adaptation, and on which time scales the effects take place. The present human EEG study investigated the potential influence of the overall spectral range as well as the spectral spacing of the acoustic stimulation spectrum on frequency-specific neural adaptation. Tones randomly varying in frequency were presented passively and computational modeling of frequency-specific neural adaptation was used. Frequency-specific adaptation was observed for all presentation conditions. Critically, however, the spread of adaptation (i.e., degree of coadaptation) in tonotopically organized regions of auditory cortex changed with the spectral range of the acoustic stimulation. In contrast, spectral spacing did not affect the spread of frequency-specific adaptation. Therefore, changes in neural sensitivity in auditory cortex are directly coupled to the overall spectral range of the acoustic stimulation, which suggests that neural adjustments to spectral stimulus statistics occur over a time scale of multiple seconds. PMID:24381293

Schlichting, Nadine; Obleser, Jonas

2014-01-01

205

NASA Astrophysics Data System (ADS)

This study evaluates how statistical and dynamical downscaling models as well as combined approach perform in retrieving the space-time variability of near-surface temperature and rainfall, as well as their extremes, over the whole Mediterranean region. The dynamical downscaling model used in this study is the Weather Research and Forecasting (WRF) model with varying land-surface models and resolutions (20 and 50 km) and the statistical tool is the Cumulative Distribution Function-transform (CDF-t). To achieve a spatially resolved downscaling over the Mediterranean basin, the European Climate Assessment and Dataset (ECA&D) gridded dataset is used for calibration and evaluation of the downscaling models. In the frame of HyMeX and MED-CORDEX international programs, the downscaling is performed on ERA-I reanalysis over the 1989-2008 period. The results show that despite local calibration, CDF-t produces more accurate spatial variability of near-surface temperature and rainfall with respect to ECA&D than WRF which solves the three-dimensional equation of conservation. This first suggests that at 20-50 km resolutions, these three-dimensional processes only weakly contribute to the local value of temperature and precipitation with respect to local one-dimensional processes. Calibration of CDF-t at each individual grid point is thus sufficient to reproduce accurately the spatial pattern. A second explanation is the use of gridded data such as ECA&D which smoothes in part the horizontal variability after data interpolation and damps the added value of dynamical downscaling. This explains partly the absence of added-value of the 2-stage downscaling approach which combines statistical and dynamical downscaling models. The temporal variability of statistically downscaled temperature and rainfall is finally strongly driven by the temporal variability of its forcing (here ERA-Interim or WRF simulations). CDF-t is thus efficient as a bias correction tool but does not show any added-value regarding the time variability of the downscaled field. Finally, the quality of the reference observation dataset is a key issue. Comparison of CDF-t calibrated with ECA&D dataset and WRF simulations to local measurements from weather stations not assimilated in ECA&D, shows that the temporal variability of the downscaled data with respect to the local observations is closer to the local measurements than to ECA&D data. This highlights the strong added-value of dynamical downscaling which improves the temporal variability of the atmospheric dynamics with regard to the driving model. This article highlights the benefits and inconveniences emerging from the use of both downscaling techniques for climate research. Our goal is to contribute to the discussion on the use of downscaling tools to assess the impact of climate change on regional scales.

Flaounas, Emmanouil; Drobinski, Philippe; Vrac, Mathieu; Bastin, Sophie; Lebeaupin-Brossier, Cindy; Stéfanon, Marc; Borga, Marco; Calvet, Jean-Christophe

2013-06-01

206

Statistical Mechanics with focus on

Statistical Mechanics with focus on Liquids, Solutions and Colloidal Systems Course contents A. Foundations of statistical mechanics Classical dynamics Â Hamilton's and Liouville's equations The concept thermodynamics and statistical mechanics. B. Liquid state theory; Equilibrium statistical mechanics for liquids

Johannesson, Henrik

207

A comparison of statistical and dynamical downscaling for surface temperature in North America

Projections from general circulation model (GCM) simulations must be downscaled to the high spatial resolution needed for assessing local and regional impacts of climate change, but uncertainties in the downscaling process are difficult to quantify. We employed a multiple linear regression model and the MM5 dynamical model to downscale June, July, and August monthly mean surface temperature over eastern North

Scott Spak; Tracey Holloway; Barry Lynn; Richard Goldberg

2007-01-01

208

. Evidences from lowÂdimensional cases show that the topological properties of such systems are similar from exponential to power law. 0. Introduction A smooth dynamical system is almost hyperbolic be quite di#erent from that of a uniformly hyperbolic system, even though we can make them topologically

Hu, Huyi

209

NASA Astrophysics Data System (ADS)

Navigation Satellite System (GNSS)-based radio occultation (RO) is a satellite remote sensing technique providing accurate profiles of the Earth's atmosphere for weather and climate applications. Above about 30 km altitude, however, statistical optimization is a critical process for initializing the RO bending angles in order to optimize the climate monitoring utility of the retrieved atmospheric profiles. Here we introduce an advanced dynamic statistical optimization algorithm, which uses bending angles from multiple days of European Centre for Medium-range Weather Forecasts (ECMWF) short-range forecast and analysis fields, together with averaged-observed bending angles, to obtain background profiles and associated error covariance matrices with geographically varying background uncertainty estimates on a daily updated basis. The new algorithm is evaluated against the existing Wegener Center Occultation Processing System version 5.4 (OPSv5.4) algorithm, using several days of simulated MetOp and observed CHAMP and COSMIC data, for January and July conditions. We find the following for the new method's performance compared to OPSv5.4: 1.) it significantly reduces random errors (standard deviations), down to about half their size, and leaves less or about equal residual systematic errors (biases) in the optimized bending angles; 2.) the dynamic (daily) estimate of the background error correlation matrix alone already improves the optimized bending angles; 3.) the subsequently retrieved refractivity profiles and atmospheric (temperature) profiles benefit by improved error characteristics, especially above about 30 km. Based on these encouraging results, we work to employ similar dynamic error covariance estimation also for the observed bending angles and to apply the method to full months and subsequently to entire climate data records.

Li, Y.; Kirchengast, G.; Scherllin-Pirscher, B.; Wu, S.; Schwaerz, M.; Fritzer, J.; Zhang, S.; Carter, B. A.; Zhang, K.

2013-12-01

210

p21{sup WAF1/Cip1/Sdi1} knockout mice respond to doxorubicin with reduced cardiotoxicity

Doxorubicin (Dox) is an antineoplastic agent that can cause cardiomyopathy in humans and experimental animals. As an inducer of reactive oxygen species and a DNA damaging agent, Dox causes elevated expression of p21{sup WAF1/Cip1/Sdi1} (p21) gene. Elevated levels of p21 mRNA and p21 protein have been detected in the myocardium of mice following Dox treatment. With chronic treatment of Dox, wild type (WT) animals develop cardiomyopathy evidenced by elongated nuclei, mitochondrial swelling, myofilamental disarray, reduced cardiac output, reduced ejection fraction, reduced left ventricular contractility, and elevated expression of ANF gene. In contrast, p21 knockout (p21KO) mice did not show significant changes in the same parameters in response to Dox treatment. In an effort to understand the mechanism of the resistance against Dox induced cardiomyopathy, we measured levels of antioxidant enzymes and found that p21KO mice did not contain elevated basal or inducible levels of glutathione peroxidase and catalase. Measurements of 6 circulating cytokines indicated elevation of IL-6, IL-12, IFN{gamma} and TNF{alpha} in Dox treated WT mice but not p21KO mice. Dox induced elevation of IL-6 mRNA was detected in the myocardium of WT mice but not p21KO mice. While the mechanism of the resistance against Dox induced cardiomyopathy remains unclear, lack of inflammatory response may contribute to the observed cardiac protection in p21KO mice. -- Highlights: Black-Right-Pointing-Pointer Doxorubicin induces p21 elevation in the myocardium. Black-Right-Pointing-Pointer Doxorubicin causes dilated cardiomyopathy in wild type mice. Black-Right-Pointing-Pointer p21 Knockout mice are resistant against doxorubicin induced cardiomyopathy. Black-Right-Pointing-Pointer Lack of inflammatory response correlates with the resistance in p21 knockout mice.

Terrand, Jerome; Xu, Beibei; Morrissy, Steve; Dinh, Thai Nho [Department of Pharmacology,College of Medicine, University of Arizona, 1501 N. Campbell Ave, Tucson, AZ 85724 (United States)] [Department of Pharmacology,College of Medicine, University of Arizona, 1501 N. Campbell Ave, Tucson, AZ 85724 (United States); Williams, Stuart [Biomedical Engineering Program, College of Medicine, University of Arizona, 1501 N. Campbell Ave, Tucson, AZ 85724 (United States)] [Biomedical Engineering Program, College of Medicine, University of Arizona, 1501 N. Campbell Ave, Tucson, AZ 85724 (United States); Chen, Qin M., E-mail: qchen@email.arizona.edu [Department of Pharmacology,College of Medicine, University of Arizona, 1501 N. Campbell Ave, Tucson, AZ 85724 (United States)

2011-11-15

211

Developing a Web-based system by integrating VGI and SDI for real estate management and marketing

NASA Astrophysics Data System (ADS)

Property importance of various aspects, especially the impact on various sectors of the economy and the country's macroeconomic is clear. Because of the real, multi-dimensional and heterogeneous nature of housing as a commodity, the lack of an integrated system includes comprehensive information of property, the lack of awareness of some actors in this field about comprehensive information about property and the lack of clear and comprehensive rules and regulations for the trading and pricing, several problems arise for the people involved in this field. In this research implementation of a crowd-sourced Web-based real estate support system is desired. Creating a Spatial Data Infrastructure (SDI) in this system for collecting, updating and integrating all official data about property is also desired in this study. In this system a Web2.0 broker and technologies such as Web services and service composition has been used. This work aims to provide comprehensive and diverse information about property from different sources. For this purpose five-level real estate support system architecture is used. PostgreSql DBMS is used to implement the desired system. Geoserver software is also used as map server and reference implementation of OGC (Open Geospatial Consortium) standards. And Apache server is used to run web pages and user interfaces. Integration introduced methods and technologies provide a proper environment for various users to use the system and share their information. This goal is only achieved by cooperation between all involved organizations in real estate with implementation their required infrastructures in interoperability Web services format.

Salajegheh, J.; Hakimpour, F.; Esmaeily, A.

2014-10-01

212

NASA Astrophysics Data System (ADS)

A crucial step for proposing relevant long-term mitigation measures in long term avalanche forecasting is the accurate definition of high return period avalanches. Recently, "statistical-dynamical" approach combining a numerical model with stochastic operators describing the variability of its inputs-outputs have emerged. Their main interests is to take into account the topographic dependency of snow avalanche runout distances, and to constrain the correlation structure between model's variables by physical rules, so as to simulate the different marginal distributions of interest (pressure, flow depth, etc.) with a reasonable realism. Bayesian methods have been shown to be well adapted to achieve model inference, getting rid of identifiability problems thanks to prior information. An important problem which has virtually never been considered before is the validation of the predictions resulting from a statistical-dynamical approach (or from any other engineering method for computing extreme avalanches). In hydrology, independent "fossil" data such as flood deposits in caves are sometimes confronted to design discharges corresponding to high return periods. Hence, the aim of this work is to implement a similar comparison between high return period avalanches obtained with a statistical-dynamical approach and independent validation data resulting from careful dendrogeomorphological reconstructions. To do so, an up-to-date statistical model based on the depth-averaged equations and the classical Voellmy friction law is used on a well-documented case study. First, parameter values resulting from another path are applied, and the dendrological validation sample shows that this approach fails in providing realistic prediction for the case study. This may be due to the strongly bounded behaviour of runouts in this case (the extreme of their distribution is identified as belonging to the Weibull attraction domain). Second, local calibration on the available avalanche chronicle is performed with various prior distributions resulting from expert knowledge and/or other paths. For all calibrations, a very successful convergence is obtained, which confirms the robustness of the used Metropolis-Hastings estimation algorithm. This also demonstrates the interest of the Bayesian framework for aggregating information by sequential assimilation in the frequently encountered case of limited data quantity. Confrontation with the dendrological sample stresses the predominant role of the Coulombian friction coefficient distribution's variance on predicted high magnitude runouts. The optimal fit is obtained for a strong prior reflecting the local bounded behavior, and results in a 10-40 m difference for return periods ranging between 10 and 300 years. Implementing predictive simulations shows that this is largely within the range of magnitude of uncertainties to be taken into account. On the other hand, the different priors tested for the turbulent friction coefficient influence predictive performances only slightly, but have a large influence on predicted velocity and flow depth distributions. This all may be of high interest to refine calibration and predictive use of the statistical-dynamical model for any engineering application.

Eckert, Nicolas; Schläppy, Romain; Jomelli, Vincent; Naaim, Mohamed

2013-04-01

213

NASA Technical Reports Server (NTRS)

A statistical study of the subauroral electron temperature enhancement was undertaken using Langmuir probe observations during 488 traversals of the midlatitude plasmapause region by the DE-2 satellite. The subauroral electron temperature enhancement on the nightside is a quasi-permanent feature at all altitudes between 350 and 1000 km with an occurrence frequency that depends on altitude. The occurrence frequency of the subauroral electron temperature peak has a strong altitude dependence on the dayside. The position of the subauroral Te peak decreases with increasing magnetic activity in a manner similar to that of the equatorial plasmapause and other midlatitude plasmapause signatures.

Kozyra, J. U.; Cravens, T. E.; Nagy, A. F.; Brace, L. H.

1986-01-01

214

The $\\bar{\\Omega}/\\Omega$ ratio originating from string decays is predicted to be larger than unity in proton proton interactions at SPS energies ($E_{\\rm lab}$=160 GeV). The anti-omega dominance increases with decreasing beam energy. This surprising behavior is caused by the combinatorics of quark-antiquark production in small and low-mass strings. Since this behavior is not found in a statistical description of hadron production in proton proton collisions, it may serve as a key observable to probe the hadronization mechanism in such collisions.

Bleicher, M; Keränen, A; Aichelin, Jörg; Bass, S A; Becattini, F; Redlich, Krzysztof; Werner, K

2002-01-01

215

The $\\bar{\\Omega}/\\Omega$ ratio originating from string decays is predicted to be larger than unity in proton proton interactions at SPS energies ($E_{\\rm lab}$=160 GeV). The anti-omega dominance increases with decreasing beam energy. This surprising behavior is caused by the combinatorics of quark-antiquark production in small and low-mass strings. Since this behavior is not found in a statistical description of hadron production in proton proton collisions, it may serve as a key observable to probe the hadronization mechanism in such collisions.

M. Bleicher; F. M. Liu; A. Keränen; J. Aichelin; S. A. Bass; F. Becattini; K. Redlich; K. Werner

2001-11-15

216

NASA Astrophysics Data System (ADS)

Time series of pressure measured on the periphery of the central section of a circular cylinder of aspect ratio 22 are used to investigate the dynamics of the local reattachments during the drag crisis transitions. A succession of multi-stable dynamics are identified and characterized through conditional statistical analysis as the Reynolds number is increased. The first transition marking an abrupt weakening of the periodic pressure fluctuations associated to the global shedding dynamics is accompanied by the appearance of symmetric and bistable perturbations. Afterwards, two scenarii of asymmetric and symmetric boundary layer reattachments are found. The asymmetric scenario leads to two transitions. During the first transition, the flow explores randomly three stable states to eventually stabilize on the state corresponding to the permanent reattachment on one side of the cylinder. The second transition is bistable and leads to the permanent reattachment on both sides. For the second symmetric scenario, the boundary layer reattachments occur simultaneously on both side of the cylinder. In that case, the flow explores randomly two stable states to eventually stabilize on the state of full reattachment. Pressure distributions of all of these states are characterized as well as their corresponding probabilities during the drag crisis transitions of the critical regime.

Cadot, O.; Desai, A.; Mittal, S.; Saxena, S.; Chandra, B.

2015-01-01

217

Retrieval dynamics and retention in cross-situational statistical word learning.

Previous research on cross-situational word learning has demonstrated that learners are able to reduce ambiguity in mapping words to referents by tracking co-occurrence probabilities across learning events. In the current experiments, we examined whether learners are able to retain mappings over time. The results revealed that learners are able to retain mappings for up to 1 week later. However, there were interactions between the amount of retention and the different learning conditions. Interestingly, the strongest retention was associated with a learning condition that engendered retrieval dynamics that initially challenged the learner but eventually led to more successful retrieval toward the end of learning. The ease/difficulty of retrieval is a critical process underlying cross-situational word learning and is a powerful example of how learning dynamics affect long-term learning outcomes. PMID:24117698

Vlach, Haley A; Sandhofer, Catherine M

2014-01-01

218

The vitality of brewing yeasts has been used to monitor their physiological state during fermentation. To investigate the fermentation process, we used the image processing software, CalMorph, which generates morphological data on yeast mother cells and bud shape, nuclear shape and location, and actin distribution. We found that 248 parameters changed significantly during fermentation. Successive use of principal component analysis (PCA) revealed several important features of yeast, providing insight into the dynamic changes in the yeast population. First, PCA indicated that much of the observed variability in the experiment was summarized in just two components: a change with a peak and a change over time. Second, PCA indicated the independent and important morphological features responsible for dynamic changes: budding ratio, nucleus position, neck position, and actin organization. Thus, the large amount of data provided by imaging analysis can be used to monitor the fermentation processes involved in beer and bioethanol production. PMID:24012106

Ohnuki, Shinsuke; Enomoto, Kenichi; Yoshimoto, Hiroyuki; Ohya, Yoshikazu

2014-03-01

219

Dynamics and Statistical Mechanics of Rotating and non-Rotating Vortical Flows

Three projects were analyzed with the overall aim of developing a computational/analytical model for estimating values of the energy, angular momentum, enstrophy and total variation of fluid height at phase transitions between disordered and self-organized flow states in planetary atmospheres. It is believed that these transitions in equilibrium statistical mechanics models play a role in the construction of large-scale, stable structures including super-rotation in the Venusian atmosphere and the formation of the Great Red Spot on Jupiter. Exact solutions of the spherical energy-enstrophy models for rotating planetary atmospheres by Kac's method of steepest descent predicted phase transitions to super-rotating solid-body flows at high energy to enstrophy ratio for all planetary spins and to sub-rotating modes if the planetary spin is large enough. These canonical statistical ensembles are well-defined for the long-range energy interactions that arise from 2D fluid flows on compact oriented manifolds such as the surface of the sphere and torus. This is because in Fourier space available through Hodge theory, the energy terms are exactly diagonalizable and hence has zero range, leading to well-defined heat baths.

Lim, Chjan [RPI] [RPI

2013-12-18

220

STATISTICAL METHODS STATISTICAL METHODS

STATISTICAL METHODS 1 STATISTICAL METHODS Arnaud Delorme, Swartz Center for Computational@salk.edu. Keywords: statistical methods, inference, models, clinical, software, bootstrap, resampling, PCA, ICA Abstract: Statistics represents that body of methods by which characteristics of a population are inferred

Delorme, Arnaud

221

Dynamic Stability of the Solar System: Statistically Inconclusive Results from Ensemble Integrations

NASA Astrophysics Data System (ADS)

Due to the chaotic nature of the solar system, the question of its long-term stability can only be answered in a statistical sense, for instance, based on numerical ensemble integrations of nearby orbits. Destabilization of the inner planets, leading to close encounters and/or collisions can be initiated through a large increase in Mercury's eccentricity, with a currently assumed likelihood of ~1%. However, little is known at present about the robustness of this number. Here I report ensemble integrations of the full equations of motion of the eight planets and Pluto over 5 Gyr, including contributions from general relativity. The results show that different numerical algorithms lead to statistically different results for the evolution of Mercury's eccentricity (e_M}). For instance, starting at present initial conditions (e_M}? 0.21), Mercury's maximum eccentricity achieved over 5 Gyr is, on average, significantly higher in symplectic ensemble integrations using heliocentric rather than Jacobi coordinates and stricter error control. In contrast, starting at a possible future configuration (e_M}? 0.53), Mercury's maximum eccentricity achieved over the subsequent 500 Myr is, on average, significantly lower using heliocentric rather than Jacobi coordinates. For example, the probability for e_M} to increase beyond 0.53 over 500 Myr is >90% (Jacobi) versus only 40%-55% (heliocentric). This poses a dilemma because the physical evolution of the real system—and its probabilistic behavior—cannot depend on the coordinate system or the numerical algorithm chosen to describe it. Some tests of the numerical algorithms suggest that symplectic integrators using heliocentric coordinates underestimate the odds for destabilization of Mercury's orbit at high initial e_M}.

Zeebe, Richard E.

2015-01-01

222

Escape beam statistics and dynamical properties for a periodically corrugated waveguide

NASA Astrophysics Data System (ADS)

Some escape and dynamical properties for a beam of light inside a corrugated waveguide are discussed by using Fresnel reflectance. The system is described by a mapping and is controlled by a parameter ? defining a transition from integrability (?=0) to non integrability (??0). The phase space is mixed containing periodic islands, chaotic seas and invariant tori. The histogram of escaping orbits is shown to be scaling invariant with respect to ?. The waveguide is immersed in a region with different refractive index. Different optical materials are used to overcame the results.

da Costa, Diogo Ricardo; Silva, Mário R.; Leonel, Edson D.

2014-04-01

223

NASA Astrophysics Data System (ADS)

This paper reports on the determination of ?S from lattice simulations with 2+1+1 twisted-mass dynamical flavors via the computation of the ghost-gluon coupling renormalized in the momentum substraction Taylor scheme. A high-statistics sample of gauge configurations used to evaluate the coupling from ghost and gluon propagators allows for the appropriate update of previous results, now performing an improved analysis of data with reduced statistical errors and the systematical uncertainties under a better control.

Blossier, B.; Boucaud, Ph.; Brinet, M.; De Soto, F.; Morenas, V.; Pène, O.; Petrov, K.; Rodríguez-Quintero, J.

2014-01-01

224

A number of important questions in ecology involve the possibility of interactions or "coupling" among potential components of ecological systems. The basic question of whether two components are coupled (exhibit dynamical interdependence) is relevant to investigations of movement of animals over space, population regulation, food webs and trophic interactions, and is also useful in the design of monitoring programs. For example, in spatially extended systems, coupling among populations in different locations implies the existence of redundant information in the system and the possibility of exploiting this redundancy in the development of spatial sampling designs. One approach to the identification of coupling involves study of the purported mechanisms linking system components. Another approach is based on time series of two potential components of the same system and, in previous ecological work, has relied on linear cross-correlation analysis. Here we present two different attractor-based approaches, continuity and mutual prediction, for determining the degree to which two population time series (e.g., at different spatial locations) are coupled. Both approaches are demonstrated on a one-dimensional predator-prey model system exhibiting complex dynamics. Of particular interest is the spatial asymmetry introduced into the model as linearly declining resource for the prey over the domain of the spatial coordinate. Results from these approaches are then compared to the more standard cross-correlation analysis. In contrast to cross-correlation, both continuity and mutual prediction are clearly able to discern the asymmetry in the flow of information through this system. PMID:15649520

Nichols, J M; Moniz, L; Nichols, J D; Pecora, L M; Cooch, E

2005-02-01

225

Financial price dynamics and pedestrian counterflows: a comparison of statistical stylized facts.

We propose and document the evidence for an analogy between the dynamics of granular counterflows in the presence of bottlenecks or restrictions and financial price formation processes. Using extensive simulations, we find that the counterflows of simulated pedestrians through a door display eight stylized facts observed in financial markets when the density around the door is compared with the logarithm of the price. Finding so many stylized facts is very rare indeed among all agent-based models of financial markets. The stylized properties are present when the agents in the pedestrian model are assumed to display a zero-intelligent behavior. If agents are given decision-making capacity and adapt to partially follow the majority, periods of herding behavior may additionally occur. This generates the very slow decay of the autocorrelation of absolute return due to an intermittent dynamics. Our findings suggest that the stylized facts in the fluctuations of the financial prices result from a competition of two groups with opposite interests in the presence of a constraint funneling the flow of transactions to a narrow band of prices with limited liquidity. PMID:23410385

Parisi, Daniel R; Sornette, Didier; Helbing, Dirk

2013-01-01

226

Financial price dynamics and pedestrian counterflows: A comparison of statistical stylized facts

NASA Astrophysics Data System (ADS)

We propose and document the evidence for an analogy between the dynamics of granular counterflows in the presence of bottlenecks or restrictions and financial price formation processes. Using extensive simulations, we find that the counterflows of simulated pedestrians through a door display eight stylized facts observed in financial markets when the density around the door is compared with the logarithm of the price. Finding so many stylized facts is very rare indeed among all agent-based models of financial markets. The stylized properties are present when the agents in the pedestrian model are assumed to display a zero-intelligent behavior. If agents are given decision-making capacity and adapt to partially follow the majority, periods of herding behavior may additionally occur. This generates the very slow decay of the autocorrelation of absolute return due to an intermittent dynamics. Our findings suggest that the stylized facts in the fluctuations of the financial prices result from a competition of two groups with opposite interests in the presence of a constraint funneling the flow of transactions to a narrow band of prices with limited liquidity.

Parisi, Daniel R.; Sornette, Didier; Helbing, Dirk

2013-01-01

227

A number of important questions in ecology involve the possibility of interactions or ?coupling? among potential components of ecological systems. The basic question of whether two components are coupled (exhibit dynamical interdependence) is relevant to investigations of movement of animals over space, population regulation, food webs and trophic interactions, and is also useful in the design of monitoring programs. For example, in spatially extended systems, coupling among populations in different locations implies the existence of redundant information in the system and the possibility of exploiting this redundancy in the development of spatial sampling designs. One approach to the identification of coupling involves study of the purported mechanisms linking system components. Another approach is based on time series of two potential components of the same system and, in previous ecological work, has relied on linear cross-correlation analysis. Here we present two different attractor-based approaches, continuity and mutual prediction, for determining the degree to which two population time series (e.g., at different spatial locations) are coupled. Both approaches are demonstrated on a one-dimensional predator?prey model system exhibiting complex dynamics. Of particular interest is the spatial asymmetry introduced into the model as linearly declining resource for the prey over the domain of the spatial coordinate. Results from these approaches are then compared to the more standard cross-correlation analysis. In contrast to cross-correlation, both continuity and mutual prediction are clearly able to discern the asymmetry in the flow of information through this system.

Nichols, J.M.; Moniz, L.; Nichols, J.D.; Pecora, L.M.; Cooch, E.

2005-01-01

228

A stochastic-dynamic model for global atmospheric mass field statistics

NASA Technical Reports Server (NTRS)

A model that yields the spatial correlation structure of atmospheric mass field forecast errors was developed. The model is governed by the potential vorticity equation forced by random noise. Expansion in spherical harmonics and correlation function was computed analytically using the expansion coefficients. The finite difference equivalent was solved using a fast Poisson solver and the correlation function was computed using stratified sampling of the individual realization of F(omega) and hence of phi(omega). A higher order equation for gamma was derived and solved directly in finite differences by two successive applications of the fast Poisson solver. The methods were compared for accuracy and efficiency and the third method was chosen as clearly superior. The results agree well with the latitude dependence of observed atmospheric correlation data. The value of the parameter c sub o which gives the best fit to the data is close to the value expected from dynamical considerations.

Ghil, M.; Balgovind, R.; Kalnay-Rivas, E.

1981-01-01

229

Avalanche statistics and time-resolved grain dynamics for a driven heap

We probe the dynamics of intermittent avalanches caused by steady addition of grains to a quasi-two dimensional heap. To characterize the time-dependent average avalanche flow speed v(t), we image the top free surface. To characterize the grain fluctuation speed dv(t), we use Speckle-Visibility Spectroscopy. During an avalanche, we find that the fluctuation speed is approximately one-tenth the average flow speed, and that these speeds are largest near the beginning of an event. We also find that the distribution of event durations is peaked, and that event sizes are correlated with the time interval since the end of the previous event. At high rates of grain addition, where successive avalanches merge into smooth continuous flow, the relationship between average and fluctuation speeds changes to dv Sqrt[v].

A. R. Abate; H. Katsuragi; D. J. Durian

2007-08-08

230

We study the quantum many-body dynamics in the entropy production of $N=10$ interacting identical bosons in an external harmonic trap. We use the multiconfigurational time-dependent Hartree for bosons or MCTDHB, an essentially exact many-body theory, for the solution of the time-dependent Schr\\"odinger equation. We introduce new and genuinely many-body measures for the entropy production that relate to the time-dependent many-body basis set used in MCTDHB. With these measures, we demonstrate the transition from regular or quasi-periodic to irregular or chaotic dynamics in the time-evolution of quantum information (Shannon) entropy, number of principal basis components and inverse participation ratio for various repulsive interaction strengths on a many-body level. The many-body Shannon information entropy approaches the value of $\\ln(0.48 D)$, where $D$ is the number of time-dependent many-body states employed in the MCTDHB computations for larger interaction strength, as predicted by the Gaussian orthogonal ensemble (GOE) of random matrices. This is a clear signature of statistical relaxation, here demonstrated for the first time with a genuine many-body entropy measure. We find a fundamental connection between the production of entropy, the build-up of correlations and the loss of coherence.

A. U. J. Lode; B. Chakrabarti; V. K. B. Kota

2015-01-12

231

NASA Astrophysics Data System (ADS)

A statistical-dynamical downscaling (SDD) approach for the regionalisation of wind energy output (Eout) over Europe with special focus on Germany is proposed. SDD uses an extended circulation weather type (CWT) analysis on global daily MSLP fields with the central point being located over Germany. 77 weather classes based on the associated circulation weather type and the intensity of the geostrophic flow are identified. Representatives of these classes are dynamical downscaled with the regional climate model COSMO-CLM. By using weather class frequencies of different datasets the simulated representatives are recombined to probability density functions (PDFs) of near-surface wind speed and finally to Eout of a sample wind turbine for present and future climate. This is performed for reanalysis, decadal hindcasts and long-term future projections. For evaluation purposes results of SDD are compared to wind observations and to simulated Eout of purely dynamical downscaling (DD) methods. For the present climate SDD is able to simulate realistic PDFs of 10m-wind speed for most stations in Germany. The resulting spatial Eout patterns are similar to DD simulated Eout. In terms of decadal hindcasts results of SDD are similar to DD simulated Eout over Germany, Poland, Czech Republic, and Benelux, for which high correlations between annual Eout timeseries of SDD and DD are detected for selected hindcasts. Lower correlation is found for other European countries. It is demonstrated that SDD can be used to downscale the full ensemble of the MPI-ESM decadal prediction system. Long-term climate change projections in SRES scenarios of ECHAM5/MPI-OM as obtained by SDD agree well to results of other studies using DD methods, with increasing Eout over Northern Europe and a negative trend over Southern Europe. Despite some biases it is concluded that SDD is an adequate tool to assess regional wind energy changes in large model ensembles.

Pinto, Joaquim G.; Reyers, Mark; Mömken, Julia

2014-05-01

232

Plants have always been a supreme source of drugs and India is endowed with a wide variety of them with high medicinal values. The Quorum Sensing (QS) quenching efficiency of various solvent extracts of Melia dubia seeds was investigated against uropathogenic Escherichia coli (UPEC) to screen the competitive inhibitor of SdiA, a transcriptional activator of quorum sensing in E. coli. In this study, potentiality of five different extracts of Melia dubia seeds for quorum sensing inhibitory activity was investigated against uropathogenic Escherichia coli (UPEC). Assays such as cell density, swarming motility, protein, protease, hemolysis, hemagglutination, hydrophobicity and biofilm inhibition were performed. Biofilm, hemolysis and swarming motility were found to be inhibited by 92.1%, 20.9 % and 48.52% respectively, when the medium was supplemented with 30 mg/ml of the ethanolic extract. GC-MS spectrum of the ethanolic extract showed an array of 27 structurally unlinked compounds with natural ligand C8HSL. The docking against QS transcriptional regulator SdiA was predicted by in silico studies and the ligand C6 showed significant activity with -10.8 GScore. In vitro and in silico docking analysis showed fairly a good correlation, suggesting that the ethanolic extract showed potency to attenuate quorum sensing of uropathogenic E. coli. Further studies by in vitro and in vivo strategies are necessary to foresee the quorum quenching effect of the ligands. PMID:23210902

Ravichandiran, Vinothkannan; Shanmugam, Karthi; Solomon, Adline Princy

2013-09-01

233

This report reviews previous attempt to develop strategic defenses, the technologies currently under consideration, their main unknowns, and their likely performance relative to evolving threats. 28 refs.

Canavan, G.H.

1988-01-01

234

This paper examines the hydrologic model performance in three snowmelt-dominated basins in the western United States to dynamically- and statistically downscaled output from the National Centers for Environmental Prediction\\/National Center for Atmospheric Research Reanalysis (NCEP). Runoff produced using a distributed hydrologic model is compared using daily precipitation and maximum and minimum temperature timeseries derived from the following sources: (1) NCEP

L. E. Hay; M. P. Clark

235

This paper examines the hydrologic model performance in three snowmelt-dominated basins in the western United States to dynamically- and statistically downscaled output from the National Centers for Environmental Prediction\\/National Center for Atmospheric Research Reanalysis (NCEP). Runoff produced using a distributed hydrologic model is compared using daily precipitation and maximum and minimum temperature timeseries derived from the following sources: (1) NCEP

L. E. Hay; M. P. Clark

2003-01-01

236

The statistical-dynamical annual water balance model of Eagleson (1978) is a pioneering work in the analysis of climate, soil and vegetation interactions. This paper describes several enhancements and modifications to the model that improve its physical realism at the expense of its mathematical elegance and analytical tractability. In particular, the analytical solutions for the root zone fluxes are re-derived using

J. P. Kochendorfer; J. A. Ramírez

2010-01-01

237

The statistical-dynamical annual water balance model of Eagleson (1978) is a pioneering work in the analysis of climate, soil and vegetation interactions. This paper describes several enhancements and modifications to the model that improve its physical realism at the expense of its mathematical elegance and analytical tractability. In particular, the analytical solutions for the root zone fluxes are re-derived using

J. P. Kochendorfer; J. A. Ramírez

2008-01-01

238

NASA Astrophysics Data System (ADS)

We derive new constraints on the mass, rotation, orbit structure, and statistical parallax of the Galactic old nuclear star cluster and the mass of the supermassive black hole. We combine star counts and kinematic data from Fritz et al., including 2500 line-of-sight velocities and 10 000 proper motions obtained with VLT instruments. We show that the difference between the proper motion dispersions ?l and ?b cannot be explained by rotation, but is a consequence of the flattening of the nuclear cluster. We fit the surface density distribution of stars in the central 1000 arcsec by a superposition of a spheroidal cluster with scale ˜100 arcsec and a much larger nuclear disc component. We compute the self-consistent two-integral distribution function f(E, Lz) for this density model, and add rotation self-consistently. We find that (i) the orbit structure of the f(E, Lz) gives an excellent match to the observed velocity dispersion profiles as well as the proper motion and line-of-sight velocity histograms, including the double-peak in the vl-histograms. (ii) This requires an axial ratio near q1 = 0.7 consistent with our determination from star counts, q1 = 0.73 ± 0.04 for r < 70 arcsec. (iii) The nuclear star cluster is approximately described by an isotropic rotator model. (iv) Using the corresponding Jeans equations to fit the proper motion and line-of-sight velocity dispersions, we obtain best estimates for the nuclear star cluster mass, black hole mass, and distance M*(r < 100 arcsec) = (8.94 ± 0.31|stat ± 0.9|syst) × 106 M?, M• = (3.86 ± 0.14|stat ± 0.4|syst) × 106 M?, and R0 = 8.27 ± 0.09|stat ± 0.1|syst kpc, where the estimated systematic errors account for additional uncertainties in the dynamical modelling. (v) The combination of the cluster dynamics with the S-star orbits around Sgr A* strongly reduces the degeneracy between black hole mass and Galactic Centre distance present in previous S-star studies. A joint statistical analysis with the results of Gillessen et al., gives M• = (4.23 ± 0.14) × 106 M? and R0 = 8.33 ± 0.11 kpc.

Chatzopoulos, S.; Fritz, T. K.; Gerhard, O.; Gillessen, S.; Wegg, C.; Genzel, R.; Pfuhl, O.

2015-02-01

239

NASA Astrophysics Data System (ADS)

The global climate community has produced a wide range of results from atmospheric-ocean general circulation models, which are considered as the primary source of information on the future climate change. However, there are still gaps between the spatial resolution of climate model outputs and the point-scale requirement of most of climate change impact studies. Thus, empirical-statistical downscaling (ESD) and dynamical downscaling (DD) techniques continue to be used as alternatives and various models have been made available by the scientific community. Several comparative studies have been done during the last decade,dealing with downscaling local weather variables such as temperature and precipitation over a region of interest. Accordingly, in this work, new methods and strategies based on merging ESD and DD results will be proposed in order to increase the quality of the local climate projections with a special focus on seasonal and decadal precipitation and temperature based on CMIP3/5 experiments. A new freely available ESD R-package developed by MET Norway is used and will be also presented.

Mezghani, Abdelkader; Benestad, Rasmus E.

2014-05-01

240

NASA Astrophysics Data System (ADS)

Some time ago two apparently dissimilar presentations were given at the 2007 Helmholtz Workshop in Berlin. One by J. Douthett and R. Krantz focused on the commonality between the mathematical descriptions of musical scales and the long-ranged, one-dimensional, anti-ferromagnetic Ising model of statistical physics. The other by J. Cartwright, D. Gonzalez, and O. Piro articulated a nonlinear dynamical model of pitch perception. Both approaches lead to a Farey series devil's staircase structure. In the first case, the ground state magnetic phase diagram of the Ising model is a Farey series devil's staircase. In the second case, the ear is modeled as a nonlinear system leading to a three-frequency resonant pitch perception model of the auditory system that exhibits a devil's staircase phase-locked structure. In this poster we present a summary of each of these works side-by-side to illuminate the link between these two seemingly disparate systems. Adapted from JMM Vol. 4, No. 1, 57, Mar. 2010.

Krantz, Richard; Douthett, Jack; Cartwright, Julyan; Gonzalez, Diego; Piro, Oreste

2010-10-01

241

Technology Transfer Automated Retrieval System (TEKTRAN)

Quorum sensing transcriptional regulator SdiA has been shown to enhance the survival of Escherichia coli O157:H7 (O157) in the acidic compartment of bovine rumen in response to N-acyl-L-homoserine lactones (AHLs) produced by the rumen bacteria. Bacteria that survive the rumen environment subsequentl...

242

A molecular, mean-field theory of chain packing statistics in aggregates of amphiphilic molecules is applied to calculate the conformational properties of the lipid chains comprising the hydrophobic cores of dipalmitoyl-phosphatidylcholine (DPPC), dioleoyl-phosphatidylcholine (DOPC), and palmitoyl-oleoyl-phosphatidylcholine (POPC) bilayers in their fluid state. The central quantity in this theory, the probability distribution of chain conformations, is evaluated by minimizing the free energy of the bilayer assuming only that the segment density within the hydrophobic region is uniform (liquidlike). Using this distribution we calculate chain conformational properties such as bond orientational order parameters and spatial distributions of the various chain segments. The lipid chains, both the saturated palmitoyl (-(CH2)14-CH3) and the unsaturated oleoyl (-(CH2)7-CH = CH-(CH2)7-CH3) chains are modeled using rotational isomeric state schemes. All possible chain conformations are enumerated and their statistical weights are determined by the self-consistency equations expressing the condition of uniform density. The hydrophobic core of the DPPC bilayer is treated as composed of single (palmitoyl) chain amphiphiles, i.e., the interactions between chains originating from the same lipid headgroup are assumed to be the same as those between chains belonging to different molecules. Similarly, the DOPC system is treated as a bilayer of oleoyl chains. The POPC bilayer is modeled as an equimolar mixture of palmitoyl and oleoyl chains. Bond orientational order parameter profiles, and segment spatial distributions are calculated for the three systems above, for several values of the bilayer thickness (or, equivalently, average area/headgroup) chosen, where possible, so as to allow for comparisons with available experimental data and/or molecular dynamics simulations. In most cases the agreement between the mean-field calculations, which are relatively easy to perform, and the experimental and simulation data is very good, supporting their use as an efficient tool for analyzing a variety of systems subject to varying conditions (e.g., bilayers of different compositions or thicknesses at different temperatures). PMID:7811955

Fattal, D R; Ben-Shaul, A

1994-01-01

243

Congressional Campaign Contributions, District Service and Electoral Outcomes in theUnited States: Statistical Tests of a Formal Game Model with Nonlinear DynamicsUsing a two-stage game model of congressional campaigns, the second stage being a system ofordinary di#erential equations, I argue that candidates, political parties and #nancial contributorsinteract strategically in American congressional elections in a way that is inherently nonlinear.Congressional races in

Walter R. Mebane

1998-01-01

244

Understanding the role of lipid metabolism in ovarian physiology is crucial for the progression of reproductive biotechnology. The aim in this work was to explore the lipid composition and dynamics of ovarian tissue, specifically the stroma, follicles, and corpora lutea. Desorption electrospray ionization-mass spectrometry (DESI-MS), an ambient ionization technique, was applied in this investigation, acquiring chemical and spatial information simultaneously. A morphologically-friendly solvent, dimethylformamide-acetonitrile (1:1), was used for DESI-MS imaging which allowed for ovarian lipid characterisation and subsequent staining (hematoxylin and eosin) providing morphological information. By this approach, regions-of-interest (ROI) were selected from bovine (n=8), swine (n=3), and mice (n=5) ovaries (including pre-pubescent and cycling adults) based on the stained morphological structures. ROI for stroma (n=54), follicles (n=89), and corpora lutea (n=61) were selected and chemically profiled. Tissue sections (20?m) were thaw mounted onto glass microscope slides and stored at -80°C until analysis. A linear ion trap mass spectrometer equipped with a custom DESI-MS imaging stage was operated in the negative ion mode (m/z 200 to 1000). A 300×300µm pixel size was used in DESI-MS imaging of ovarian tissue. Hyperspectral DESI images were reconstructed and processed by principal component analysis (PCA) that allowed visualisation of relationships among spatial (i.e. morphology) and chemical features. Ions indicated by PCA were analysed using univariate analysis (ANOVA), supporting the significance of particular lipids between morphological structures, e.g. adrenic acid (P = 1.7×10(-8)) and m/z 836 (P=8.9×10(-9)) between corpora lutea and follicles. All morphological structures could be differentiated by multivariate statistics (>90% prediction rate) independent of the species, indicating conserved lipid constitution. Smaller differences in the lipid profiles were noted between species, poly-ovulatory and mono-ovulatory species, and reproductive maturation. A large variety and abundance of lipids was observed in corpora lutea and follicles, where steroidogenesis is a prominent physiological activity. Additional insight into ovarian physiology was gained with the detection of arachidonic and adrenic acid. The spatial relationship of arachidonic and adrenic acid with the corpora lutea - the former is a known prostaglandin precursor and key signalling molecule in steroidogenesis regulation and the latter is metabolized in the prostaglandin pathway by the same enzymes - suggests the latter may also have a role in steroidogenesis regulation, previously unseen in ovarian physiology. DESI-MS imaging with morphologically-driven statistical analysis proved efficient in relating and interpreting the chemical and morphological features. This methodology can by further applied to unravel complex ovarian-related physiological mechanisms and to other physiological and physiopathological models. PMID:25472236

Jarmusch, A K; Ferreira, C R; Eberlin, L S; Pirro, V

2014-12-01

245

NASA Astrophysics Data System (ADS)

This work presents the first analysis of long-term correlative day-to-night columnar aerosol optical properties. The aim is to better understand columnar aerosol dynamic from ground-based observations, which are poorly studied until now. To this end we have used a combination of sun-and-star photometry measurements acquired in the city of Granada (37.16° N, 3.60° W, 680 m a.s.l.; South-East of Spain) from 2007 to 2010. For the whole study period, mean aerosol optical depth (AOD) around 440 nm (± standard deviation) is 0.18 ± 0.10 and 0.19 ± 0.11 for daytime and nighttime, respectively, while the mean Angström exponent (?) is 1.0 ± 0.4 and 0.9 ± 0.4 for daytime and nighttime. The ANOVA statistical tests reveal that there are no significant differences between AOD and ? obtained at daytime and those at nighttime. Additionally, the mean daytime values of AOD and ? obtained during this study period are coherent with the values obtained in the surrounding AERONET stations. On the other hand, AOD around 440 nm present evident seasonal patterns characterised by large values in summer (mean value of 0.20 ± 0.10 both at daytime and nighttime) and low values in winter (mean value of 0.15 ± 0.09 at daytime and 0.17 ± 0.10 at nighttime). The Angström exponents also present seasonal patterns, but with low values in summer (mean values of 0.8 ± 0.4 and 0.9 ± 0.4 at day- and night-time) and relatively large values in winter (mean values of 1.2 ± 0.4 and 1.0 ± 0.3 at daytime and nighttime). These seasonal patterns are explained by the differences in the meteorological conditions and by the differences in the strength of the aerosol sources. To take more insight about the changes in aerosol particles between day and night, the spectral differences of the Angström exponent as function of the Angström exponent are also studied. These analyses reveal increases of the fine mode radius and of the fine mode contribution to AOD during nighttime, being more remarkable in the summer seasons. These variations are explained by the changes of the local aerosol sources and by the meteorological conditions between daytime and nighttime, as well as aerosol aging processes. Case studies during summer and winter for different aerosol loads and types are also presented to clearly illustrate these findings.

Pérez-Ramírez, D.; Lyamani, H.; Olmo, F. J.; Whiteman, D. N.; Alados-Arboledas, L.

2012-10-01

246

NASA Technical Reports Server (NTRS)

This work presents the first analysis of longterm correlative day-to-night columnar aerosol optical properties. The aim is to better understand columnar aerosol dynamic from ground-based observations, which are poorly studied until now. To this end we have used a combination of sun-and-star photometry measurements acquired in the city of Granada (37.16 N, 3.60 W, 680 ma.s.l.; South-East of Spain) from 2007 to 2010. For the whole study period, mean aerosol optical depth (AOD) around 440 nm (+/-standard deviation) is 0.18 +/- 0.10 and 0.19 +/- 0.11 for daytime and nighttime, respectively, while the mean Angstr¨om exponent (alpha ) is 1.0 +/- 0.4 and 0.9 +/- 0.4 for daytime and nighttime. The ANOVA statistical tests reveal that there are no significant differences between AOD and obtained at daytime and those at nighttime. Additionally, the mean daytime values of AOD and obtained during this study period are coherent with the values obtained in the surrounding AERONET stations. On the other hand, AOD around 440 nm present evident seasonal patterns characterised by large values in summer (mean value of 0.20 +/- 0.10 both at daytime and nighttime) and low values in winter (mean value of 0.15 +/- 0.09 at daytime and 0.17 +/- 0.10 at nighttime). The Angstr¨om exponents also present seasonal patterns, but with low values in summer (mean values of 0.8 +/- 0.4 and 0.9 +/- 0.4 at dayand night-time) and relatively large values in winter (mean values of 1.2 +/- 0.4 and 1.0 +/- 0.3 at daytime and nighttime). These seasonal patterns are explained by the differences in the meteorological conditions and by the differences in the strength of the aerosol sources. To take more insight about the changes in aerosol particles between day and night, the spectral differences of the Angstrom exponent as function of the Angstr¨om exponent are also studied. These analyses reveal increases of the fine mode radius and of the fine mode contribution to AOD during nighttime, being more remarkable in the summer seasons. These variations are explained by the changes of the local aerosol sources and by the meteorological conditions between daytime and nighttime, as well as aerosol aging processes. Case studies during summer and winter for different aerosol loads and types are also presented to clearly illustrate these findings.

Ramirez, Daniel Perez; Lyamani, H.; Olmo, F. J.; Whiteman, D. N.; Alados-Arboledas, L.

2012-01-01

247

NASA Astrophysics Data System (ADS)

The Pacific multidecadal climate variability (PMV) is an important phenomenon that has significant economic and societal impact. In this study, the PMV in the Community Climate System Model version 3 (CCSM3) is investigated with a combined statistical and dynamical approach. In favorable comparison to observations, the modeled North Pacific climate system undergoes coherent multidecadal atmospheric and oceanic variability of a characteristic quasi-50-year timescale, with apparent connections to the tropical Indo-Pacific. Specifically designed sensitivity experiments are performed to explicitly identify the origin of the PMV. The results support a North Pacific origin for the PMV, with the tropical Pacific responding passively. Furthermore, the PMV is suggested to rely on propagating Rossby waves in the subpolar North Pacific Ocean. A first mechanism of the PMV is then advanced based on a more thorough analysis, characterized by a crucial role of the subpolar North Pacific. The multidecadal temperature and salinity signal is found to originate in the subsurface of the subpolar North Pacific, as result of the wave adjustment to the preceding basin-scale wind curl forcing. The temperature and salinity anomaly then upwells to the surface and is amplified through local temperature-salinity convective feedback. Along the southward Oyashio current, the anomaly travel to the Kuroshio Extension (KOE) and is further intensified through a similar convective feedback in addition to the wind-evaporation-SST (WES) feedback. The temperature anomalies in the KOE is able to feedback to the atmosphere inducing wind curl anomaly over the subpolar North Pacific, which in turn generates wave propagation and causes temperature and salinity variability in the subpolar subsurface. Thereby, a closed loop of PMV is established, in form of an extratropical delayed oscillator. The delayed negative feedback resides in the wave adjustment of the subpolar North Pacific Ocean via propagating Rossby waves, while the convective feedback and WES feedback provide the positive feedback. The North Pacific originated PMV is able to significantly impact the tropical Pacific and other sectors of the globe through atmospheric teleconnections.

Zhong, Yafang

248

NASA Astrophysics Data System (ADS)

We discuss the nonequilibrium dynamics of a quantum Ising chain following a quantum quench of the transverse field and in the presence of a Gaussian time-dependent noise. We discuss the probability distribution of the work done on the system both for static and dynamic noise. While the effect of static noise is to smooth the low energy threshold of the statistic of the work, appearing for sudden quenches, a dynamical noise protocol affects also the spectral weight of such features. We also provide a detailed derivation of the kinetic equation for the Green's functions on the Keldysh contour and the time evolution of observables of physical interest, extending previously reported results [Marino and Silva, Phys. Rev. B 86, 060408 (2012), 10.1103/PhysRevB.86.060408], and discussing the extension of the concept of prethermalization which can be used to study noisy quantum many-body Hamiltonians driven out of equilibrium.

Marino, Jamir; Silva, Alessandro

2014-01-01

249

... 1975-2011 Did You Know? Video Series Cancer Statistics Understanding Cancer Statistics Learn definitions of statistical terms, how cancer statistics are used, and how population-based cancer statistics ...

250

, often with an emphasis on quantum gases such as spin-polarized hydrogen or helium (see also review 12 analyze the validity of the Fermi-liquid approach to transverse dynamics of spin-polarized gases interpretation for zero-temperature dissipative pro- cesses, observed recently in spin dynamics

Meyerovich, Alex

251

Ultrasonic light scattering tomography system is a new imaging technique for breast function, which associates with diffused optical tomography (DOT) with ultrasonic examination. It locates breast neoplasm with ultrasonic examination and measures the total hemoglobin concentration inside the tumor with DOT photon emission to reflect the metabolic state of tumors and then comes to synthesis diagnostic index to judge benign and malignant tumors. This diagnosis method has significant affection on diagnosis of benign and malignant tumors at home and abroad. In the development of breast cancer, local tissue hypoxia leads to a large number of new blood vessels when the tumor grows faster than the rate of angiogenesis. A recent study found microvessel density (MVD), vascular endothelial growth factor (VEGF) and hypoxia-inducible factor-1 alpha (HIF-1?) play a major role in angiogenesis of breast cancer. This study analyses the relationship between breast cancer ultrasound synthesis diagnostic index (SDI) and the expression of MVD, VEGF and HIF-1? by testing the expression level of the breast cancer gene MVD, VEGF and HIF-1?. PMID:24659092

Wang, Hai-long; Zhang, Zhou-long

2014-09-01

252

Statistical Downscaling of Daily Wind Speed Variations MEGAN C. KIRCHMEIER

: statistical and dynamical. Dynamical downscaling typi- cally employs the use of a regional climate model (RCM complete description of RCMs and dynamical downscaling. Al- though computationally expensive, dynamicalStatistical Downscaling of Daily Wind Speed Variations MEGAN C. KIRCHMEIER Department

Wisconsin at Madison, University of

253

We report first results from a spatiotemporal statistical analysis of ionospheric emissions as observed by the Ultraviolet Imager (UVI) onboard the POLAR spacecraft during 4 months of 1997 and 1998. Approximately 12,300 individual emission events near local midnight with durations exceeding the sampling time of the image sequences are investigated. The probability distributions of these events over the lifetime T,

Vadim M. Uritsky; Alex J. Klimas; Dimitris Vassiliadis; Damien Chua; George Parks

2002-01-01

254

information de- rived from ElectroMagnetic Articulograph (EMA) data into its inner states. It maps from the EMA data in the MOCHA database. We solely relied on the EMA data to perform speech synthesis, in contrast to the more common approach of learn- ing a statistical mapping between the EMA and acoustic

Stern, Richard

255

This study analyzes the effects of thermocline shoaling on the ocean internal wave (IW) generation in the north South China Sea (NSCS). Seven years of satellite synthetic aperture radar (SAR) images from 1995 to 2001 are used for the statistical analysis of IW occurrence, and field measurements of sea surface wind, sea state, and vertical temperature profiles are used for

Quanan Zheng; R. Dwi Susanto; Chung-Ru Ho; Y. Tony Song; Qing Xu

2007-01-01

256

NASA Astrophysics Data System (ADS)

The statistical-dynamical annual water balance model of Eagleson (1978) is a pioneering work in the analysis of climate, soil and vegetation interactions. This paper describes several enhancements and modifications to the model that improve its physical realism at the expense of its mathematical elegance and analytical tractability. In particular, the analytical solutions for the root zone fluxes are re-derived using separate potential rates of transpiration and bare-soil evaporation. Those potential rates, along with the rate of evaporation from canopy interception, are calculated using the two-component Shuttleworth-Wallace (1985) canopy model. In addition, the soil column is divided into two layers, with the upper layer representing the dynamic root zone. The resulting ability to account for changes in root-zone water storage allows for implementation at the monthly timescale. This new version of the Eagleson model is coined the Statistical-Dynamical Ecohydrology Model (SDEM). The ability of the SDEM to capture the seasonal dynamics of the local-scale soil-water balance is demonstrated for two grassland sites in the US Great Plains. Sensitivity of the results to variations in peak green leaf area index (LAI) suggests that the mean peak green LAI is determined by some minimum in root zone soil moisture during the growing season. That minimum appears to be close to the soil matric potential at which the dominant grass species begins to experience water stress and well above the wilting point, thereby suggesting an ecological optimality hypothesis in which the need to avoid water-stress-induced leaf abscission is balanced by the maximization of carbon assimilation (and associated transpiration). Finally, analysis of the sensitivity of model-determined peak green LAI to soil texture shows that the coupled model is able to reproduce the so-called "inverse texture effect", which consists of the observation that natural vegetation in dry climates tends to be most productive in sandier soils despite their lower water holding capacity. Although the determination of LAI based on complete or near-complete utilization of soil moisture is not a new approach in ecohydrology, this paper demonstrates its use for the first time with a new monthly statistical-dynamical model of the water balance. Accordingly, the SDEM provides a new framework for studying the controls of soil texture and climate on vegetation density and evapotranspiration.

Kochendorfer, J. P.; Ramírez, J. A.

2010-10-01

257

NASA Astrophysics Data System (ADS)

The statistical-dynamical annual water balance model of Eagleson (1978) is a pioneering work in the analysis of climate, soil and vegetation interactions. This paper describes several enhancements and modifications to the model that improve its physical realism at the expense of its mathematical elegance and analytical tractability. In particular, the analytical solutions for the root zone fluxes are re-derived using separate potential rates of transpiration and bare-soil evaporation. Those potential rates, along with the rate of evaporation from canopy interception, are calculated using the two-component Shuttleworth-Wallace (1985) canopy model. In addition, the soil column is divided into two layers, with the upper layer representing the dynamic root zone. The resulting ability to account for changes in root-zone water storage allows for implementation at the monthly timescale. This new version of the Eagleson model is coined the Statistical-Dynamical Ecohydrology Model (SDEM). The ability of the SDEM to capture the seasonal dynamics of the local-scale soil-water balance is demonstrated for two grassland sites in the US Great Plains. Sensitivity of the results to variations in peak green Leaf Area Index (LAI) suggests that the mean peak green LAI is determined by some minimum in root zone soil moisture during the growing season. That minimum appears to be close to the soil matric potential at which the dominant grass species begins to experience water stress and well above the wilting point, thereby suggesting an ecological optimality hypothesis in which the need to avoid water-stress-induced leaf abscission is balanced by the maximization of carbon assimilation (and associated transpiration). Finally, analysis of the sensitivity of model-determined peak green LAI to soil texture shows that the coupled model is able to reproduce the so-called "inverse texture effect", which consists of the observation that natural vegetation in dry climates tends to be most productive in sandier soils despite their lower water holding capacity. Although the determination of LAI based on near-complete utilization of soil moisture is not a new approach in ecohydrology, this paper demonstrates its use for the first time with a new monthly statistical-dynamical model of the water balance. Accordingly, the SDEM provides a new framework for studying the controls of soil texture and climate on vegetation density and evapotranspiration.

Kochendorfer, J. P.; Ramírez, J. A.

2008-03-01

258

NASA Astrophysics Data System (ADS)

The Hydro-Kansas (HK) is a multi-institutional, multi-investigator, multi-disciplinary research project. It represents the first illustrative example of a Natural Laboratory (NL), as described in the Water, Earth, Biota (WEB) report to the National Science Foundation (http://cires.colorado.edu/hydrology). HK combines theoretical analyses, numerical modeling, and an observational field program to understand and predict floods during periods of stationary and non-stationary changes in global hydro-climate. The framework is being generalized to include riparian evapotranspiration (RET). The central observational facility of HK is the 1,100 km2 Whitewater basin 50 km east of Wichita, Kansas. HK is addressing the long-standing problem of predicting spatial statistical scale invariance, or scaling, in floods and RET from bio-physical processes on multiple time scales that range from those of individual rainfall-runoff events to annual and longer. Physical predictions of statistical scaling involve non-linear interactions among hydrologic, geomorphologic, atmospheric, climatic, and ecologic processes in mesoscale basins. They require, (i) multi-scale dynamical formulations, (ii) a new ensemble approach to solve multi-scale dynamical equations on random self-similar (RSN) river networks, (iii) diagnostic analyses of theoretical predictions using observations, and (iv) a framework to generalize the results across global hydroclimates. Progress on these four sets of research challenges will be illustrated through examples.

Gupta, V. K.

2009-05-01

259

Statistical Laboratory & Department of Statistics

Statistical Laboratory & Department of Statistics Annual Report July 1, 2005 to December 31, 2006...............................................33 Statistical Computing Section ......................................34 CSSM and statistical methodology in the nutritional sciences. We were also very pleased to secure a permanent lecturer

260

The $\\\\bar{\\\\Omega}\\/\\\\Omega$ ratio originating from string decays is predicted to be larger than unity in proton proton interactions at SPS energies ($E_{\\\\rm lab}$=160 GeV). The anti-omega dominance increases with decreasing beam energy. This surprising behavior is caused by the combinatorics of quark-antiquark production in small and low-mass strings. Since this behavior is not found in a statistical description of hadron

M Bleicher; Liu Fu Ming; A Keränen; Jörg Aichelin; S A Bass; F Becattini; Krzysztof Redlich; K Werner

2001-01-01

261

The production of recombinant anti-HIV peptide, T-20, in Escherichia coli was optimized by statistical experimental designs (successive designs with multifators) such as 24–1 fractional factorial, 23 full factorial, and 22 rotational central composite design in order. The effects of media compositions (glucose, NPK sources, MgSO4, and trace elements), induction level, induction timing (optical density at induction process), and induction duration

Kwang-Min Lee; Chang-Hoon Rhee; Choong-Kyung Kang; Jung-Hoe Kim

2006-01-01

262

We study by means of an Eulerian-Lagrangian model the statistical properties of velocity and acceleration of a neutrally-buoyant finite-sized particle in a turbulent flow statistically homogeneous and isotropic. The particle equation of motion, beside added mass and steady Stokes drag, keeps into account the unsteady Stokes drag force - known as Basset-Boussinesq history force - and the non-Stokesian drag based on Schiller-Naumann parametrization, together with the finite-size Faxen corrections. We focus on the case of flow at low Taylor-Reynolds number, Re_lambda ~ 31, for which fully resolved numerical data which can be taken as a reference are available (Homann & Bec 651 81-91 J. Fluid Mech. (2010)). Remarkably, we show that while drag forces have always minor effects on the acceleration statistics, their role is important on the velocity behavior. We propose also that the scaling relations for the particle velocity variance as a function of its size, which have been first detected in fully resolved si...

Calzavarini, Enrico; Leveque, Emmanuel; Pinton, Jean-Francois; Toschi, Federico

2010-01-01

263

In this work we present a dynamically biased statistical model to describe the evolution of the title reaction from statistical to a more direct mechanism, using quasi-classical trajectories (QCT). The method is based on the one previously proposed by Park and Light [J. Chem. Phys. 126, 044305 (2007)]. A recent global potential energy surface is used here to calculate the capture probabilities, instead of the long-range ion-induced dipole interactions. The dynamical constraints are introduced by considering a scrambling matrix which depends on energy and determine the probability of the identity/hop/exchange mechanisms. These probabilities are calculated using QCT. It is found that the high zero-point energy of the fragments is transferred to the rest of the degrees of freedom, what shortens the lifetime of H(5)(+) complexes and, as a consequence, the exchange mechanism is produced with lower proportion. The zero-point energy (ZPE) is not properly described in quasi-classical trajectory calculations and an approximation is done in which the initial ZPE of the reactants is reduced in QCT calculations to obtain a new ZPE-biased scrambling matrix. This reduction of the ZPE is explained by the need of correcting the pure classical level number of the H(5)(+) complex, as done in classical simulations of unimolecular processes and to get equivalent quantum and classical rate constants using Rice-Ramsperger-Kassel-Marcus theory. This matrix allows to obtain a ratio of hop/exchange mechanisms, ?(T), in rather good agreement with recent experimental results by Crabtree et al. [J. Chem. Phys. 134, 194311 (2011)] at room temperature. At lower temperatures, however, the present simulations predict too high ratios because the biased scrambling matrix is not statistical enough. This demonstrates the importance of applying quantum methods to simulate this reaction at the low temperatures of astrophysical interest. PMID:22957565

Gómez-Carrasco, Susana; González-Sánchez, Lola; Aguado, Alfredo; Sanz-Sanz, Cristina; Zanchet, Alexandre; Roncero, Octavio

2012-09-01

264

NASA Astrophysics Data System (ADS)

In this work we present a dynamically biased statistical model to describe the evolution of the title reaction from statistical to a more direct mechanism, using quasi-classical trajectories (QCT). The method is based on the one previously proposed by Park and Light [J. Chem. Phys. 126, 044305 (2007), 10.1063/1.2430711]. A recent global potential energy surface is used here to calculate the capture probabilities, instead of the long-range ion-induced dipole interactions. The dynamical constraints are introduced by considering a scrambling matrix which depends on energy and determine the probability of the identity/hop/exchange mechanisms. These probabilities are calculated using QCT. It is found that the high zero-point energy of the fragments is transferred to the rest of the degrees of freedom, what shortens the lifetime of H_5^+ complexes and, as a consequence, the exchange mechanism is produced with lower proportion. The zero-point energy (ZPE) is not properly described in quasi-classical trajectory calculations and an approximation is done in which the initial ZPE of the reactants is reduced in QCT calculations to obtain a new ZPE-biased scrambling matrix. This reduction of the ZPE is explained by the need of correcting the pure classical level number of the H_5^+ complex, as done in classical simulations of unimolecular processes and to get equivalent quantum and classical rate constants using Rice-Ramsperger-Kassel-Marcus theory. This matrix allows to obtain a ratio of hop/exchange mechanisms, ?(T), in rather good agreement with recent experimental results by Crabtree et al. [J. Chem. Phys. 134, 194311 (2011), 10.1063/1.3587246] at room temperature. At lower temperatures, however, the present simulations predict too high ratios because the biased scrambling matrix is not statistical enough. This demonstrates the importance of applying quantum methods to simulate this reaction at the low temperatures of astrophysical interest.

Gómez-Carrasco, Susana; González-Sánchez, Lola; Aguado, Alfredo; Sanz-Sanz, Cristina; Zanchet, Alexandre; Roncero, Octavio

2012-09-01

265

Oscillation: ENSO, the Atlantic Multidecadal52 Oscillation: AMO, the Atlantic Meridional Mode: AMM, and the North Atlantic53 Oscillation: NAO) affecting changes in large-scale circulations on decadal and541 Extended-range seasonal hurricane forecasts for the North Atlantic2 with a hybrid dynamical

Webster, Peter J.

266

NASA Astrophysics Data System (ADS)

Statistical physics and information theory is applied to the clinical chemistry measurements present in a patient database containing 2.5 million patients' data over a 20-year period. Despite the seemingly naive approach of aggregating all patients over all times (with respect to particular clinical chemistry measurements), both a diurnal signal in the decay of the time-delayed mutual information and the presence of two sub-populations with differing health are detected. This provides a proof in principle that the highly fragmented data in electronic health records has potential for being useful in defining disease and human phenotypes.

Albers, D. J.; Hripcsak, George

2010-02-01

267

Quasi-classical, direct dynamics trajectories were calculated at the B3LYP/6-31G* level of theory, in an attempt to understand decomposition mechanisms of 1-ethyl-3-methylimidazolium dicyanamide (EMIM(+)DCA(-)) and 1-ethyl-2,3-dimethylimidazolium dicyanamide (EMMIM(+)DCA(-)). The trajectories showed many dissociation paths for these two ionic liquids. Using trajectory results as a guide, structures of transition states and products that might be important for decomposition of these two compounds were determined using density functional theory calculations. Rice-Ramsperger-Kassel-Marcus (RRKM) theory was then utilized to examine properties of energized ionic liquids and to determine unimolecular rates for crossing various transition states. On the basis of RRKM modeling, initial decomposition paths for energized EMIM(+)DCA(-) correspond to formation of an N-heterocyclic carbene and acid pair via transfer of the C2 proton of EMIM(+) to DCA(-), and evolution of methylimidazole and ethylimidazole via SN2 alkyl abstraction by DCA(-). Similar decomposition paths were identified for energized EMMIM(+)DCA(-), except that the reactivity of C2 of the imidazolium cation is significantly reduced upon substitution of a methyl group for a hydrogen atom at this position. The present work demonstrates that dynamics simulations, in conjunction with statistical modeling, are able to provide insight into decomposition mechanisms, kinetics, and dynamics for alkylimidazolium-based ionic liquids and to predict product branching ratios and how they vary with decomposition temperatures. PMID:25275818

Liu, Jianbo; Chambreau, Steven D; Vaghjiani, Ghanshyam L

2014-11-26

268

NASA Astrophysics Data System (ADS)

Comparisons between the experimental and predicted sound transmission loss values obtained from statistical energy analysis are presented for two foam-filled honeycomb sandwich panels. Statistical energy analysis (SEA) is a modeling procedure which uses energy flow relationships for the theoretical estimation of the sound transmission through structures in resonant motion. The accuracy of the prediction of the sound transmission loss using SEA greatly depends on accurate estimates of: (1) the modal density, (2) the internal loss factor, and (3) the coupling loss factor parameters of the structures. A theoretical expression for the modal density of sandwich panels is developed from a sixth-order governing equation. Measured modal density estimates of the two foam-filled honeycomb sandwich panels are obtained by using a three-channel spectral method with a spectral mass correction to allow for the mass loading of the impedance head. The effect of mass loading of the accelerometer is corrected in the estimations of both the total loss factor and radiation loss factor of the sandwich panels.

Zhou, Ran; Crocker, Malcolm J.

2010-03-01

269

... Topics Drugs & Supplements Videos & Cool Tools ESPAÑOL MedlinePlus Statistics To use the sharing features on this page, please enable JavaScript. Quarterly User Statistics Graph | Quarterly User Statistics Table | Number of Health ...

270

Background Left ventricular (LV) dyssynchrony is associated with increased risk of all-cause mortality in patients with end-stage renal disease. Our aim was to determine the associations of LV dynamic dyssynchrony with peritoneal solute clearance in continuous ambulatory peritoneal dialysis (CAPD) patients. Our primary objective was to determine the association between dynamic LV dyssynchrony and CAPD clearance at 2 years. Secondary objectives were to identify the factors influencing dynamic dyssynchrony, and to examine the association between dialysis adequacy and echocardiography-assessed LV outcomes. Methods Fifty CAPD patients and 13 healthy volunteers underwent three-dimensional (3D) dobutamine stress echocardiography (DSE). The main endpoint was systolic dyssynchrony index (SDI). Secondary endpoints, including NT-proBNP, troponin I, Kt/V, and biochemical parameters, were measured before stress echocardiography, and Kt/V was measured again 2 years later. All values are expressed as medians and interquartile ranges (IQR). Results NT-proBNP (3872 [808–11779] vs. 4.99 [4.99–36.83] pg/mL, P < 0.001), and log NT-proBNP (3.587 [2.896–4.071] vs. 0.698 [0.698–1.540], P < 0.001) levels were significantly higher in the CAPD group than in the control group. Real-time 3D DSE showed that the systolic dyssynchrony index was significantly different between the two groups at the peak dobutamine stage (1.11% [0.76–1.64%] vs. 0.66% [0.50–1.02%], P = 0.004), but not at resting (1.30% [0.89–1.74%] vs. 1.22 % [0.72–1.68%], P = 0.358).The subgroup of patients in the CAPD group with greater improvements in dialysis adequacy had lower baseline dynamic SDI and more favorable echocardiographic findings at 2 years. Dialysis adequacy decreased significantly at 2 year in patients with higher, but not in those with lower dynamic SDI at baseline. In multivariate linear regression analysis, log NT-proBNP and SDI at the peak dobutamine dose were significantly associated with Kt/V and weekly creatinine clearance at 2 years, while log NT-proBNP was significant associated with SDI at the peak dobutamine stage. Female CAPD patients group had more pronounced dynamic LV dyssynchrony compared with male patients. Conclusions Dynamic systolic dyssynchrony was strongly associated with future dialysis adequacy in CAPD patients. Log NT-proBNP was the important predictor of dynamic dyssynchrony. Our study confirmed the concept that cardiac dysfunction has an impact on dialysis adequacy. PMID:23521832

2013-01-01

271

32. Statistics 1 32. STATISTICS

32. Statistics 1 32. STATISTICS Revised September 2007 by G. Cowan (RHUL). This chapter gives an overview of statistical methods used in High Energy Physics. In statistics, we are interested in using's validity or to determine the values of its parameters. There are two main approaches to statistical

Masci, Frank

272

Department of Statistics STATISTICS COLLOQUIUM

Department of Statistics STATISTICS COLLOQUIUM ERIC KOLACZYK Department of Statistics Boston University Statistical Analysis of Network Data: (Re)visiting the Foundations MONDAY, October 13, 2014, at 4, statistical methods and modeling have been central to these efforts. But how well do we truly understand

273

NASA Astrophysics Data System (ADS)

We study numerically in this work the statistical and dynamical properties of the clusters in a one dimensional small world model. The parameters chosen correspond to a realistic network of children of school age where a disease like measles can propagate. Extensive results on the statistical behavior of the clusters around the percolation threshold, as well as the evoltion with time, are discussed. To cite this article: N. Zekri, J.P. Clerc, C. R. Physique 3 (2002) 741-747.

Zekri, Nouredine; Clerc, Jean Pierre

274

We define a new diagnostic method where computationally-intensive numerical solutions are used as an integral part of making difficult, non-contact, nanometer-scale measurements. The limited scope of this report comprises most of a due diligence investigation into implementing the new diagnostic for measuring dynamic operation of Sandia's RF Ohmic Switch. Our results are all positive, providing insight into how this switch deforms during normal operation. Future work should contribute important measurements on a variety of operating MEMS devices, with insights that are complimentary to those from measurements made using interferometry and laser Doppler methods. More generally, the work opens up a broad front of possibility where exploiting massive high-performance computers enable new measurements.

Diegert, Carl F.

2006-12-01

275

NASA Astrophysics Data System (ADS)

The study of meteorite craters on Earth provides information about the dynamic evolution of bodies within the Solar System. the Bosumtwi crater is a well studied, 10.5 km in diameter, ca. 1.07 Myr old impact structure located in Ghana. (Koeberl et al., 1997a). The impactor was ˜ 1 km in diameter, an ordinary chondrite and struck the Earth with an angle between 30o and 45o (Artemieva et al., 2004) from the horizontal. We have used a two phase backward integration to constrain the most probable parent region of the impactor. We find that the most likely source region is a high inclination object from the Middle Main Belt.

Galiazzo, M. A.; Bazsó, Á.; Huber, M. S.; Losiak, A.; Dvorak, R.; Koeberl, C.

2013-11-01

276

NASA Astrophysics Data System (ADS)

In this study, a zonally-averaged statistical climate model (SDM) is used to investigate the impact of global warming on the distribution of the geobotanic zones over the globe. The model includes a parameterization of the biogeophysical feedback mechanism that links the state of surface to the atmosphere (a bidirectional interaction between vegetation and climate). In the control experiment (simulation of the present-day climate) the geobotanic state is well simulated by the model, so that the distribution of the geobotanic zones over the globe shows a very good agreement with the observed ones. The impact of global warming on the distribution of the geobotanic zones is investigated considering the increase of CO2 concentration for the B1, A2 and A1FI scenarios. The results showed that the geobotanic zones over the entire earth can be modified in future due to global warming. Expansion of subtropical desert and semi-desert zones in the Northern and Southern Hemispheres, retreat of glaciers and sea-ice, with the Arctic region being particularly affected and a reduction of the tropical rainforest and boreal forest can occur due to the increase of the greenhouse gases concentration. The effects were more pronounced in the A1FI and A2 scenarios compared with the B1 scenario. The SDM results confirm IPCC AR4 projections of future climate and are consistent with simulations of more complex GCMs, reinforcing the necessity of the mitigation of climate change associated to global warming.

Franchito, Sergio H.; Brahmananda Rao, V.; Moraes, E. C.

2011-11-01

277

NASA Astrophysics Data System (ADS)

Despite the ubiquitous use of multi-photon and confocal microscopy measurements in biology, the core techniques typically suffer from fundamental compromises between signal to noise (S/N) and linear dynamic range (LDR). In this study, direct synchronous digitization of voltage transients coupled with statistical analysis is shown to allow S/N approaching the theoretical maximum throughout an LDR spanning more than 8 decades, limited only by the dark counts of the detector on the low end and by the intrinsic nonlinearities of the photomultiplier tube (PMT) detector on the high end. Synchronous digitization of each voltage transient represents a fundamental departure from established methods in confocal/multi-photon imaging, which are currently based on either photon counting or signal averaging. High information-density data acquisition (up to 3.2 GB/s of raw data) enables the smooth transition between the two modalities on a pixel-by-pixel basis and the ultimate writing of much smaller files (few kB/s). Modeling of the PMT response allows extraction of key sensor parameters from the histogram of voltage peak-heights. Applications in second harmonic generation (SHG) microscopy are described demonstrating S/N approaching the shot-noise limit of the detector over large dynamic ranges.

Kissick, David J.; Muir, Ryan D.; Sullivan, Shane Z.; Oglesbee, Robert A.; Simpson, Garth J.

2013-02-01

278

NASA Technical Reports Server (NTRS)

The internal waves on the continental shelf on the Middle Atlantic Bight seen on Space Shuttle photographs taken during the STS-40 mission in June 1991 are measured and analyzed. The internal wave field in the sample area has a three-level structure which consists of packet groups, packets, and solitons. An average packet group wavelength of 17.5 km and an average soliton wavelength of 0.6 km are measured. Finite-depth theory is used to derive the dynamic parameters of the internal solitons: the maximum amplitude of 5.6 m, the characteristic phase speed of 0.42 m/s, the characteristic period of 23.8 min, the velocity amplitude of the water particles in the upper and lower layers of 0.13 m/s and 0.030 m/s respectively, and the theoretical energy per unit crest line of 6.8 x 10 exp 4 J/m. The frequency distribution of solitons is triple-peaked rather than continuous. The major generation source is at 160 m water depth, and a second is at 1800 m depth, corresponding to the upper and lower edges of the shelf break.

Zheng, Quanan; Yan, Xiao-Hai; Klemas, Vic

1993-01-01

279

During in vitro selection process, it is very valuable to monitor the binding properties of the ligand population in real time, particularly the population average of the association constant in the population. If this monitoring can be realized, the selection process can be controlled in a rational way. In this paper, we present a simple method to estimate the binding properties of the ligand population during in vitro selection. The framework of the method is as follows. First, the number of all the collected ligand molecules, which are eluted after incubation and washing, is measured. Ideally, this number corresponds to the number of all the ligand molecules bound with the target-receptor or other materials in a test tube. This measurement is performed through several successive rounds of selection. Second, the measured numbers of molecules are subjected to a theoretical analysis, based on the mathematical theory of population dynamics in the selection process. Then, we can estimate the probability density of the binding free energy in the ligand population. The validity of our method was confirmed by several computer simulations based on a physicochemical model. PMID:24239675

Aita, Takuyo; Nishigaki, Koichi; Husimi, Yuzuru

2014-01-01

280

In the present work, results of investigations into the dynamics of secondary electrons with helium atoms in the presence of the reverse electric field arising in the flare of a high-voltage pulsed beam-type discharge and leading to degradation of the primary electron beam are presented. The electric field in the discharge of this type at moderate pressures can reach several hundred V/cm and leads to considerable changes in the kinetics of secondary electrons created in the process of propagation of the electron beam generated in the accelerating gap with a grid anode. Moving in the accelerating electric field toward the anode, secondary electrons create the so-called compensating current to the anode. The character of electron motion and the compensating current itself are determined by the ratio of the field strength to the concentration of atoms (E/n). The energy and angular spectra of secondary electrons are calculated by the Monte Carlo method for different ratios E/n of the electric field strength to the helium atom concentration. The motion of secondary electrons with threshold energy is studied for inelastic collisions of helium atoms and differential analysis is carried out of the collisional processes causing energy losses of electrons in helium for different E/n values. The mechanism of creation and accumulation of slow electrons as a result of inelastic collisions of secondary electrons with helium atoms and selective population of metastable states of helium atoms is considered. It is demonstrated that in a wide range of E/n values the motion of secondary electrons in the beam-type discharge flare has the character of drift. At E/n values characteristic for the discharge of the given type, the drift velocity of these electrons is calculated and compared with the available experimental data.

Demkin, V. P.; Mel'nichuk, S. V. [National Research Tomsk State University, 36, Lenin Ave., 634050 Tomsk (Russian Federation)

2014-09-15

281

NASA Technical Reports Server (NTRS)

A dynamic rain attenuation prediction model is developed for use in obtaining the temporal characteristics, on time scales of minutes or hours, of satellite communication link availability. Analagous to the associated static rain attenuation model, which yields yearly attenuation predictions, this dynamic model is applicable at any location in the world that is characterized by the static rain attenuation statistics peculiar to the geometry of the satellite link and the rain statistics of the location. Such statistics are calculated by employing the formalism of Part I of this report. In fact, the dynamic model presented here is an extension of the static model and reduces to the static model in the appropriate limit. By assuming that rain attenuation is dynamically described by a first-order stochastic differential equation in time and that this random attenuation process is a Markov process, an expression for the associated transition probability is obtained by solving the related forward Kolmogorov equation. This transition probability is then used to obtain such temporal rain attenuation statistics as attenuation durations and allowable attenuation margins versus control system delay.

Manning, Robert M.

1987-01-01

282

... About CDC.gov . Fungal Diseases Share Compartir Histoplasmosis Statistics How common is histoplasmosis? In the United States, ... Risk & Prevention Sources Diagnosis & Testing Treatment Health Professionals Statistics More Resources Blastomycosis Definition Symptoms People at Risk & ...

283

Statistics on Family Caregivers and Family Caregiving Caregiving Population Economics of Caregiving Impact on Family Caregiver's Health ... Identified Family Caregivers, 2001. Top State by State Statistics The economic value of family caregiving is detailed ...

284

We study the kicked rotator in the classically fully chaotic regime using Izrailev's N-dimensional model for various N?4000, which in the limit N?? tends to the quantized kicked rotator. We do treat not only the case K=5, as studied previously, but also many different values of the classical kick parameter 5?K?35 and many different values of the quantum parameter k?[5,60]. We describe the features of dynamical localization of chaotic eigenstates as a paradigm for other both time-periodic and time-independent (autonomous) fully chaotic or/and mixed-type Hamilton systems. We generalize the scaling variable ?=l(?)/N to the case of anomalous diffusion in the classical phase space by deriving the localization length l(?) for the case of generalized classical diffusion. We greatly improve the accuracy and statistical significance of the numerical calculations, giving rise to the following conclusions: (1) The level-spacing distribution of the eigenphases (or quasienergies) is very well described by the Brody distribution, systematically better than by other proposed models, for various Brody exponents ?(BR). (2) We study the eigenfunctions of the Floquet operator and characterize their localization properties using the information entropy measure, which after normalization is given by ?(loc) in the interval [0,1]. The level repulsion parameters ?(BR) and ?(loc) are almost linearly related, close to the identity line. (3) We show the existence of a scaling law between ?(loc) and the relative localization length ?, now including the regimes of anomalous diffusion. The above findings are important also for chaotic eigenstates in time-independent systems [Batisti? and Robnik, J. Phys. A: Math. Gen. 43, 215101 (2010); arXiv:1302.7174 (2013)], where the Brody distribution is confirmed to a very high degree of precision for dynamically localized chaotic eigenstates, even in the mixed-type systems (after separation of regular and chaotic eigenstates). PMID:23848746

Manos, Thanos; Robnik, Marko

2013-06-01

285

ERIC Educational Resources Information Center

As a branch of knowledge, Statistics is ubiquitous and its applications can be found in (almost) every field of human endeavour. In this article, the authors track down the possible source of the link between the "Siren song" and applications of Statistics. Answers to their previous five questions and five new questions on Statistics are presented.

Petocz, Peter; Sowey, Eric

2008-01-01

286

ERIC Educational Resources Information Center

The term "data snooping" refers to the practice of choosing which statistical analyses to apply to a set of data after having first looked at those data. Data snooping contradicts a fundamental precept of applied statistics, that the scheme of analysis is to be planned in advance. In this column, the authors shall elucidate the statistical…

Petocz, Peter; Sowey, Eric

2012-01-01

287

Two different techniques – replica-exchange Wang-Landau (REWL) and statistical temperature molecular dynamics (STMD) – were applied to systematically study the phase transition behavior of self-assembling lipids as a function of temperature using an off-lattice lipid model. Both methods allow the direct calculation of the density of states with improved efficiency compared to the original Wang-Landau method. A 3-segment model of amphiphilic lipids solvated in water has been studied with varied particle interaction energies (?) and lipid concentrations. The phase behavior of the lipid molecules with respect to bilayer formation has been characterized through the calculation of the heat capacity as a function of temperature, in addition to various order parameters and general visual inspection. The simulations conducted by both methods can go to very low temperatures with the whole system exhibiting well-ordered structures. With optimized parameters, several bilayer phases are observed within the temperature range studied, including gel phase bilayers with frozen water, mixed water (i.e., frozen and liquid water), and liquid water, and a more fluid bilayer with liquid water. The results obtained from both methods, STMD and REWL, are consistently in excellent agreement with each other, thereby validating both the methods and the results. PMID:23927268

Gai, Lili; Vogel, Thomas; Maerzke, Katie A.; Iacovella, Christopher R.; Landau, David P.; Cummings, Peter T.; McCabe, Clare

2013-01-01

288

X-ray integrated intensities J were measured from Si single crystals containing dislocations as a function of crystal thickness using Mo Kalpha radiation. The thickness dependence of J was compared with the statistical dynamical theory of Kato [Acta Cryst. (1980), A36, 763-769, 770-778], which contains three parameters: the static Debye-Waller factor E, the correlation length tau for the phase factor and the correlation length Gamma for the wave-field amplitudes. These three parameters are absolutely required to interpret the experimental data in contrast to the case of gamma-ray experiments in which J can be described by the parameter E alone. For our specimens, the ranges of the fitted values of tau and Gamma are 0.003-0.108 microm and 2.4-7.3 microm, respectively, depending on the reflection plane and the crystal perfection. This fact indicates that the assumption made in Kato's original theory, that Gamma is proportional to the extinction distance, should be abandoned. The reason for which the two correlation lengths can be neglected in the gamma-ray experiments is clarified. PMID:11752764

Sakaki, Daisuke; Takama, Toshihiko

2002-01-01

289

NASA Astrophysics Data System (ADS)

Two different techniques - replica-exchange Wang-Landau (REWL) and statistical temperature molecular dynamics (STMD) - were applied to systematically study the phase transition behavior of self-assembling lipids as a function of temperature using an off-lattice lipid model. Both methods allow the direct calculation of the density of states with improved efficiency compared to the original Wang-Landau method. A 3-segment model of amphiphilic lipids solvated in water has been studied with varied particle interaction energies (?) and lipid concentrations. The phase behavior of the lipid molecules with respect to bilayer formation has been characterized through the calculation of the heat capacity as a function of temperature, in addition to various order parameters and general visual inspection. The simulations conducted by both methods can go to very low temperatures with the whole system exhibiting well-ordered structures. With optimized parameters, several bilayer phases are observed within the temperature range studied, including gel phase bilayers with frozen water, mixed water (i.e., frozen and liquid water), and liquid water, and a more fluid bilayer with liquid water. The results obtained from both methods, STMD and REWL, are consistently in excellent agreement with each other, thereby validating both the methods and the results.

Gai, Lili; Vogel, Thomas; Maerzke, Katie A.; Iacovella, Christopher R.; Landau, David P.; Cummings, Peter T.; McCabe, Clare

2013-08-01

290

NASA Astrophysics Data System (ADS)

We studied the problem of understanding and computing the essential features and dynamics of molecular motions through the development of two theories for two different systems. First, we studied the process of the Berry Pseudorotation of PF5 and the rotations it induces in the molecule through its natural and intrinsic geometric nature by setting it in the language of fiber bundles and graph theory. With these tools, we successfully extracted the essentials of the process' loops and induced rotations. The infinite number of pseudorotation loops were broken down into a small set of essential loops called "super loops", with their intrinsic properties and link to the physical movements of the molecule extensively studied. In addition, only the three "self-edge loops" generated any induced rotations, and then only a finite number of classes of them. Second, we studied applying the statistical methods of Principal Components Analysis (PCA) and Principal Coordinate Analysis (PCO) to capture only the most important changes in Argon clusters so as to reduce computational costs and graph the potential energy surface (PES) in three dimensions respectively. Both methods proved successful, but PCA was only partially successful since one will only see advantages for PES database systems much larger than those both currently being studied and those that can be computationally studied in the next few decades to come. In addition, PCA is only needed for the very rare case of a PES database that does not already include Hessian eigenvalues.

Panahi, Nima S.

291

Term statistics Zipf's law text statistics

Term statistics Zipf's law text statistics October 20, 2014 text statistics 1 / 19 #12;Term statistics Zipf's law Overview 1 Term statistics 2 Zipf's law text statistics 2 / 19 #12;Term statistics Zipf's law Outline 1 Term statistics 2 Zipf's law text statistics 3 / 19 #12;Term statistics Zipf's law Model

Lu, Jianguo

292

Department of Statistics STATISTICS COLLOQUIUM

Department of Statistics STATISTICS COLLOQUIUM GOURAB MUKHERJEE Department of Statistics Stanford University Minimax Estimation of High-dimensional Predictive Densities MONDAY, February 11, 2013, at 4:00 PM investments and sports betting, have been undergoing a gradual evolution from point predic- tion towards

Stephens, Matthew

293

NSDL National Science Digital Library

This site contains materials for a college level undergraduate statistics course. The approach places emphasis on practical application. Examples are shown with hand computations and with the Minitab statistical program (V13.1). There are a couple of spreadsheets as well. Topics include: frequency distributions, graphing techniques, central tendency, variability, relative standing, correlation, dichotomous variables, continuous variables (1 and 2 sample), ANOVA: one way and two way, and nonparametric statistics.

Plonsky, Mark

2009-01-26

294

Avalanche statistics of sand heaps

Large-scale computer simulations are presented to investigate the avalanche statistics of sandpiles using molecular dynamics. We show that different methods of measurement lead to contradictory conclusions, presumably due to avalanches not reaching the end of the experimental table.

Buchholtz, V.; Poeschel, T. [Institut fuer Physik, Berlin (Germany)

1996-09-01

295

NASA Technical Reports Server (NTRS)

PURPOSE: Differences in gene expression underlie the phenotypic differences between irradiated and unirradiated cells. The goal was to identify late-transcribed genes following irradiations differing in quality, and to determine the RBE of 1 GeV/n Fe ions. MATERIALS AND METHODS: Clonogenic assay was used to determine the RBE of Fe ions. Differential hybridization to cDNA target clones was used to detect differences in expression of corresponding genes in mRNA samples isolated from MCF7 cells irradiated with iso-survival doses of Fe ions (0 or 2.5 Gy) or fission neutrons (0 or 1.2 Gy) 7 days earlier. Northern analysis was used to confirm differential expression of cDNA-specific mRNA and to examine expression kinetics up to 2 weeks after irradiation. RESULTS: Fe ion RBE values were between 2.2 and 2.6 in the lines examined. Two of 17 differentially expressed cDNA clones were characterized. hpS2 mRNA was elevated from 1 to 14 days after irradiation, whereas CIP1/WAF1/SDI1 remained elevated from 3 h to 14 days after irradiation. Induction of hpS2 mRNA by irradiation was independent of p53, whereas induction of CIP1/WAF1/SDI1 was observed only in wild-type p53 lines. CONCLUSIONS: A set of coordinately regulated genes, some of which are independent of p53, is associated with change in gene expression during the first 2 weeks post-irradiation.

Balcer-Kubiczek, E. K.; Zhang, X. F.; Harrison, G. H.; Zhou, X. J.; Vigneulle, R. M.; Ove, R.; McCready, W. A.; Xu, J. F.

1999-01-01

296

ERIC Educational Resources Information Center

In this article, the authors focus on hypothesis testing--that peculiarly statistical way of deciding things. Statistical methods for testing hypotheses were developed in the 1920s and 1930s by some of the most famous statisticians, in particular Ronald Fisher, Jerzy Neyman and Egon Pearson, who laid the foundations of almost all modern methods of…

Petocz, Peter; Sowey, Eric

2008-01-01

297

Statistical Emulator Construction for Nonlinear Smart Systems

dynamics, statistical emulators 1. Introduction Smart systems integrate sensors, actuators, and control (PVDF) is valuable in acoustic applications such as microphones [6]. High set point accuracy encourages

298

JRF (Quality, Reliability and Operations Research): 2013 INDIAN STATISTICAL INSTITUTE

-basic theory, Inventory control theory (EOQ models, dynamic demand model, concept of probabilistic modelsJRF (Quality, Reliability and Operations Research): 2013 INDIAN STATISTICAL INSTITUTE INSTRUCTIONS the following subject groups: (A) Statistics, (B) Statistical Quality Control, (C) Reliability, (D) Operations

Bandyopadhyay, Antar

299

NASA Technical Reports Server (NTRS)

Do you have elevated p-values? Is the data analysis process getting you down? Do you experience anxiety when you need to respond to criticism of statistical methods in your manuscript? You may be suffering from Insufficient Statistical Support Syndrome (ISSS). For symptomatic relief of ISSS, come for a free consultation with JSC biostatisticians at our help desk during the poster sessions at the HRP Investigators Workshop. Get answers to common questions about sample size, missing data, multiple testing, when to trust the results of your analyses and more. Side effects may include sudden loss of statistics anxiety, improved interpretation of your data, and increased confidence in your results.

Feiveson, Alan H.; Foy, Millennia; Ploutz-Snyder, Robert; Fiedler, James

2014-01-01

300

NSDL National Science Digital Library

Collaborative Statistics was written by Barbara Illowsky and Susan Dean, faculty members at De Anza College in Cupertino, California. The textbook was developed over several years and has been used in regular and honors-level classroom settings and in distance learning classes. This textbook is intended for introductory statistics courses being taken by students at twoÃ¢ÂÂ and fourÃ¢ÂÂyear colleges who are majoring in fields other than math or engineering. Intermediate algebra is the only prerequisite. The book focuses on applications of statistical knowledge rather than the theory behind it.

Dean, Susan; Illowsky, Barbara

2009-11-17

301

Non-commutative quantum field theories and their global quantum group symmetries provide an intriguing attempt to go beyond the realm of standard local quantum field theory. A common feature of these models is that the quantum group symmetry of their Hilbert spaces induces additional structure in the multiparticle states which reflects a non-trivial momentum-dependent statistics. We investigate the properties of this "rainbow statistics" in the particular context of $\\kappa$-quantum fields and discuss the analogies/differences with models with twisted statistics.

Michele Arzano; Dario Benedetti

2008-09-04

302

Engineering Statistics From "Engineering Statistics" , Top &

Engineering Statistics From "Engineering Statistics" , Top & Wiley, Prapaisri & Pongchanun 2 From "Engineering Statistics" , Top & Wiley, Prapaisri & Pongchanun 3 " "(Sample) (Sampling) ""(Population) " "(Statistics) ""(Parameter) From "Engineering Statistics" , Top & Wiley, Prapaisri

Kovintavewat, Piya

303

NSDL National Science Digital Library

Started in 1997, the Badan Pusat Statistik (BPS-Statistics Indonesia) is a non-departmental Indonesian government institution directly responsible to the Indonesian president. As the law that created this valuable institution stipulates, the BPS is intended to provide data to the government and the public, along cooperating with other international statistical institutions. Visitors looking for statistics on any number of topics will not be disappointed, as the areas covered include agriculture, consumer price indices, employment, energy, foreign trade, mining, population, public finance, tourism, and social welfare. Additionally, there are monthly macro-economic statistical reports for the years from 1998 to 2001 that can be downloaded and viewed as well. The site is rounded out by a collection of some 21 papers from the past four years that analyze various economic data from the country, such as earning data and manufacturing production.

304

We review and further develop a mathematical framework for non-equilibrium quantum statistical mechanics recently proposed in (JP4, JP5, JP6, Ru3, Ru4, Ru5, Ru6). In the alge- braic formalism of quantum statistical mechanics we introduce notions of non-equilibrium steady states, entropy production and heat fluxes, and study their properties. Our basic paradigm is a model of a small (finite) quantum system

V. Jaksi ´; C.-A. Pillet

1937-01-01

305

NASA Technical Reports Server (NTRS)

Core (0-50 eV) ion pitch angle measurements from the retarding ion mass spectrometer on Dynamics Explorer 1 are examined with respect to magnetic disturbance, invariant latitude, magnetic local time, and altitude for ions H(+), He(+), O(+), M/Z = 2 (D(+) or He(++)), and O(++). Included are outflow events in the auroral zone, polar cap, and cusp, separated into altitude regions below and above 3 R(sub E). In addition to the customary division into beam, conic, and upwelling distributions, the high-latitude observations fall into three categories corresponding to ion bulk speeds that are (1) less than, (2) comparable to, or (3) faster than that of the spacecraft. This separation, along with the altitude partition, serves to identify conditions under which ionospheric source ions are gravita- tionally bound and when they are more energetic and able to escape to the outer magnetosphere. Features of the cleft ion fountain inferred from single event studies are clearly identifiable in the statistical results. In addition, it is found that the dayside pre-noon cleft is a dayside afternoon cleft, or auroral zone, becomes an additional source for increased activity. The auroral oval as a whole appears to be a steady source of escape velocity H(+), a steady source of escape velocity He(+) ions for the dusk sector, and a source of escape velocity heavy ions for dusk local times primarily during increased activity. The polar cap above the auroral zone is a consistent source of low-energy ions, although only the lighter mass particles appear to have sufficient velocity, on average, to escape to higher altitudes. The observations support two concepts for outflow: (1) The cleft ion fountain consists of ionospheric plasma of 1-20 eV energy streaming upward into the magnetosphere where high-latitude convection electric fields cause poleward dispersion. (2) The auroral ion fountain involves field-aligned beams which flow out along auroral latitude field lines; and, in addition, for late afternoon local times, they experience additional acceleration such that the ion energy distribution tends to exceed the detection range of the instrument (greater than 50-60 eV).

Giles, B. L.; Chappell, C. R.; Moore, T. E.; Comfort, R. H.; Waite, J. H., Jr.

1994-01-01

306

NSDL National Science Digital Library

A good resource for problems in statistics in engineering. Contains some applets, and good textual examples related to engineering. Some topics include Monte Carlo method, Central Limit Theorem, Risk, Logistic Regression, Generalized Linear Models, and Confidence. Overall, this is a well presented and good site for anyone interested in engineering or mathematics.

Annis, Charles

307

NSDL National Science Digital Library

This webpage contains statistics investigations in the form of word problems. The investigations are located on the left hand side of the page on the navigation bar: the links are "Recommended Investigations" and "Additional Investigations". Within each investigation there are additional links to external resources that can be used to solve or illustrate the problem.

2013-01-01

308

Four Faculty Positions Applied Statistics & Computational Statistics

Four Faculty Positions Applied Statistics & Computational Statistics The Department of Statistics at the Assistant Professor rank. Two positions are open in the area of Applied Statistics, with a focus on the development of statistical methodology and statistical consulting. The other two positions are open

Shepp, Larry

309

Statistical characterization of dislocation ensembles

We outline a method to study the spatial and orientation statistics of dynamical dislocation systems by modeling the dislocations as a stochastic fiber process. Statistical measures have been introduced for the density, velocity, and flux of dislocations, and the connection between these measures and the dislocation state and plastic distortion rate in the crystal is explained. A dislocation dynamics simulation model has been used to extract numerical data to study the evolution of these statistical measures numerically in a body-centered cubic crystal under deformation. The orientation distribution of the dislocation density, velocity and dislocation flux, as well as the dislocation correlations have been computed. The importance of the statistical measures introduced here in building continuum models of dislocation systems is highlighted.

El-Azab, A; Deng, J; Tang, M

2006-05-17

310

Learning Statistics By Doing Statistics

NSDL National Science Digital Library

This article, created by Gary Smith of Pomona College, discusses a project-based approach to teaching statistics. The article focuses on the team aspect of learning, it introduces concepts such as: working with data, learning by doing, learning by writing, learning by speaking, and authentic assessment of material. An appendix contains a list of twenty projects that have been successfully assigned.

Smith, Gary

311

NSDL National Science Digital Library

In this statistics and probability activity students must determine whether each statement is always true, sometimes true, sometimes false, or always false. Students must have a basic understanding of probability statements and the foundation for understanding mean, median, and mode in order to complete this activity for all twelve statements. In addition to the task, tips for getting started, possible solutions, a teacher resource page, and a printable page are provided.

NRICH

2013-01-01

312

NASA Astrophysics Data System (ADS)

The Wiley Classics Library consists of selected books that have become recognized classics in their respective fields. With these new unabridged and inexpensive editions, Wiley hopes to extend the life of these important works by making them available to future generations of mathematicians and scientists. Currently available in the Series: T. W. Anderson The Statistical Analysis of Time Series T. S. Arthanari & Yadolah Dodge Mathematical Programming in Statistics Emil Artin Geometric Algebra Norman T. J. Bailey The Elements of Stochastic Processes with Applications to the Natural Sciences Robert G. Bartle The Elements of Integration and Lebesgue Measure George E. P. Box & Norman R. Draper Evolutionary Operation: A Statistical Method for Process Improvement George E. P. Box & George C. Tiao Bayesian Inference in Statistical Analysis R. W. Carter Finite Groups of Lie Type: Conjugacy Classes and Complex Characters R. W. Carter Simple Groups of Lie Type William G. Cochran & Gertrude M. Cox Experimental Designs, Second Edition Richard Courant Differential and Integral Calculus, Volume I RIchard Courant Differential and Integral Calculus, Volume II Richard Courant & D. Hilbert Methods of Mathematical Physics, Volume I Richard Courant & D. Hilbert Methods of Mathematical Physics, Volume II D. R. Cox Planning of Experiments Harold S. M. Coxeter Introduction to Geometry, Second Edition Charles W. Curtis & Irving Reiner Representation Theory of Finite Groups and Associative Algebras Charles W. Curtis & Irving Reiner Methods of Representation Theory with Applications to Finite Groups and Orders, Volume I Charles W. Curtis & Irving Reiner Methods of Representation Theory with Applications to Finite Groups and Orders, Volume II Cuthbert Daniel Fitting Equations to Data: Computer Analysis of Multifactor Data, Second Edition Bruno de Finetti Theory of Probability, Volume I Bruno de Finetti Theory of Probability, Volume 2 W. Edwards Deming Sample Design in Business Research

Goodman, Joseph W.

2000-07-01

313

NSDL National Science Digital Library

Students will encounter the concept of a distribution, along with parameters that describe a distribution's "typical" values (average) and a distribution's spread (variance). To understand simple distributions and uncertainty propagation in the coming sections, it is necessary to be familiar with the concept of statistical independence. When two variables fluctuate independently, their covariance vanishes, and the variance of their sum is the sum of their variances.

2013-06-21

314

Journal of Statistical Physics, Vol. 116, Nos. 5/6, September 2004 (Â© 2004) Of Dogs and Fleas the jumps of N fleas between two dogs. In each time step a single randomly selected flea jumps on the other dog. The more fleas there are on a dog, the more will jump off it. In the long time limit

Nagler, Jan

315

The reactions {sup 139}La + {sup 27}Al and {sup 139}La + {sup 65}Cu at {ital E}/{ital A} = 45 MeV have been modeled by combining a Boltzmann-Nordheim-Vlasov dynamical model calculation with a statistical sequential binary decay model code. For the reaction {sup 139}La + {sup 27}Al, the major features of the experimental data are adequately described by the model calculations. These features include the inclusive fragment cross sections and the total charge and source velocity distributions of multiple fragment events. Other finer features, such as charge-Dalitz plots and the branching ratios between events of different multiplicity, are not reproduced by the calculation. The failure of the calculations is even greater for the reaction {sup 139}La + {sup 65}Cu, in which only the source velocity distributions of multiple fragment events are reproduced. Because the source velocity can be a measure of how much of the target is incorporated into the projectile in inverse kinematics reactions, this suggests that the earliest stages of the reaction, described by the dynamical calculation, are adequately characterized by the model. It is the later stages of the reaction, when fragments are emitted, where the model calculation appears to fail. However, there are some indications that statistical decay in the reaction {sup 139}La + {sup 65}Cu has occurred, whether by sequential binary decays or some type of prompt multifragmentation. {copyright} {ital 1996 The American Physical Society.}

Libby, B.; Mignerey, A.C. [Department of Chemistry, University of Maryland, College Park, Maryland 20742 (United States)] [Department of Chemistry, University of Maryland, College Park, Maryland 20742 (United States); Colonna, N.; Roussel-Chomaz, P.; Wozniak, G.J.; Moretto, L.G. [Nuclear Science Division, Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States)] [Nuclear Science Division, Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States)

1996-06-01

316

In this paper we explore stochastical and statistical properties of so-called recurring spike induced Kasner sequences. Such sequences arise in recurring spike formation, which is needed together with the more familiar BKL scenario to yield a complete description of generic spacelike singularities. In particular we derive a probability distribution for recurring spike induced Kasner sequences, complementing similar available BKL results, which makes comparisons possible. As examples of applications, we derive results for so-called large and small curvature phases and the Hubble-normalized Weyl scalar.

J. Mark Heinzle; Claes Uggla

2012-12-21

317

In this study, we evaluate the accuracy of four regional climate models (NHRCM, NRAMS, TRAMS, and TWRF) and one bias correction-type statistical model (CDFDM) for daily precipitation indices under the present-day climate (1985–2004) over Japan on a 20 km grid interval. The evaluated indices are (1) mean precipitation, (2) number of days with precipitation ?1 mm\\/d (corresponds to number of

Toshichika Iizumi; Motoki Nishimori; Koji Dairaku; Sachiho A. Adachi; Masayuki Yokozawa

2011-01-01

318

We studied the problem of understanding and computing the essential features and dynamics of molecular motions through the development of two theories for two different systems. First, we studied the process of the Berry Pseudorotation of PF5 and the rotations it induces in the molecule through its natural and intrinsic geometric nature by setting it in the language of fiber

Nima S. Panahi

2007-01-01

319

The on-going 24th solar cycle (SC) is distinguished from the previous ones by low activity. On the contrary, levels of proton fluxes from galactic cosmic rays (GCR) are high, which increases the proton flow striking the Earth's radiation belts (ERB). Therefore, at present the absorbed dose from ERB protons should be calculated with consideration of the tangible increase of protons intensity built into the model descriptions based on experimental measurements during the minimum between cycles 19 and 20, and the cycle 21 maximum. The absorbed dose from GCR and ERB protons copies galactic protons dynamics, while the ERB electrons dose copies SC dynamics. The major factors that determine the absorbed dose value are SC phase, ISS orbital altitude and shielding of the dosimeter readings of which are used in analysis. The paper presents the results of dynamic analysis of absorbed doses measured by a variety of dosimeters, namely, R-16 (2 ionization chambers), DB8-1, DB8-2, DB8-3, DB8-4 as a function of ISS orbit altitude and SC phase. The existence of annual variation in the absorbed dose dynamics has been confirmed; several additional variations with the periods of 17 and 52 months have been detected. Modulation of absorbed dose variations by the SC and GCR amplitudes has been demonstrated. PMID:25035897

Mitrikas, V G

2014-01-01

320

Covariant Equilibrium Statistical Mechanics

A manifest covariant equilibrium statistical mechanics is constructed starting with a 8N dimensional extended phase space which is reduced to the 6N physical degrees of freedom using the Poincare-invariant constrained Hamiltonian dynamics describing the micro-dynamics of the system. The reduction of the extended phase space is initiated forcing the particles on energy shell and fixing their individual time coordinates with help of invariant time constraints. The Liouville equation and the equilibrium condition are formulated in respect to the scalar global evolution parameter which is introduced by the time fixation conditions. The applicability of the developed approach is shown for both, the perfect gas as well as the real gas. As a simple application the canonical partition integral of the monatomic perfect gas is calculated and compared with other approaches. Furthermore, thermodynamical quantities are derived. All considerations are shrinked on the classical Boltzmann gas composed of massive particles and hence quantum effects are discarded.

E. Lehmann

2006-02-25

321

NASA Astrophysics Data System (ADS)

The D+ +H2(v = 0, j = 0, 1) ? HD+H+ reaction has been investigated at the low energy regime by means of a statistical quantum mechanical (SQM) method. Reaction probabilities and integral cross sections (ICSs) between a collisional energy of 10-4 eV and 0.1 eV have been calculated and compared with previously reported results of a time independent quantum mechanical (TIQM) approach. The TIQM results exhibit a dense profile with numerous narrow resonances down to Ec ˜ 10-2 eV and for the case of H2(v = 0, j = 0) a prominent peak is found at ˜2.5 × 10-4 eV. The analysis at the state-to-state level reveals that this feature is originated in those processes which yield the formation of rotationally excited HD(v' = 0, j' > 0). The statistical predictions reproduce reasonably well the overall behaviour of the TIQM ICSs at the larger energy range (Ec ? 10-3 eV). Thermal rate constants are in qualitative agreement for the whole range of temperatures investigated in this work, 10-100 K, although the SQM values remain above the TIQM results for both initial H2 rotational states, j = 0 and 1. The enlargement of the asymptotic region for the statistical approach is crucial for a proper description at low energies. In particular, we find that the SQM method leads to rate coefficients in terms of the energy in perfect agreement with previously reported measurements if the maximum distance at which the calculation is performed increases noticeably with respect to the value employed to reproduce the TIQM results.

González-Lezana, Tomás; Honvault, Pascal; Scribano, Yohann

2013-08-01

322

The D(+) +H2(v = 0, j = 0, 1) ? HD+H(+) reaction has been investigated at the low energy regime by means of a statistical quantum mechanical (SQM) method. Reaction probabilities and integral cross sections (ICSs) between a collisional energy of 10(-4) eV and 0.1 eV have been calculated and compared with previously reported results of a time independent quantum mechanical (TIQM) approach. The TIQM results exhibit a dense profile with numerous narrow resonances down to Ec ~ 10(-2) eV and for the case of H2(v = 0, j = 0) a prominent peak is found at ~2.5 × 10(-4) eV. The analysis at the state-to-state level reveals that this feature is originated in those processes which yield the formation of rotationally excited HD(v' = 0, j' > 0). The statistical predictions reproduce reasonably well the overall behaviour of the TIQM ICSs at the larger energy range (Ec ? 10(-3) eV). Thermal rate constants are in qualitative agreement for the whole range of temperatures investigated in this work, 10-100 K, although the SQM values remain above the TIQM results for both initial H2 rotational states, j = 0 and 1. The enlargement of the asymptotic region for the statistical approach is crucial for a proper description at low energies. In particular, we find that the SQM method leads to rate coefficients in terms of the energy in perfect agreement with previously reported measurements if the maximum distance at which the calculation is performed increases noticeably with respect to the value employed to reproduce the TIQM results. PMID:23927256

González-Lezana, Tomás; Honvault, Pascal; Scribano, Yohann

2013-08-01

323

Non-equilibrium statistical thermodynamics

By suggesting that gas kinetic collisions are the source of irreversibility, Boltzmann's kinetic equation leads to a paradox. In a monograph entitled Non-equilibrium statistical thermodynamics, applied to fluid dynamics and laser physics the author developed an original alternative theory. The fundamental ideas supporting this new approach are traced in the present paper. It is shown that the source of irreversibility

X. de Hemptinne

1995-01-01

324

Statistical mechanics of the vacuum

The vacuum is full of virtual particles which exist for short moments of time. In this paper we construct a chaotic model of vacuum fluctuations associated with a fundamental entropic field that generates an arrow of time. The dynamics can be physically interpreted in terms of fluctuating virtual momenta. This model leads to a generalized statistical mechanics that distinguishes fundamental constants of nature.

Christian Beck

2011-12-07

325

NASA Astrophysics Data System (ADS)

The temperature ratio Ti/Te of ions to electrons affects both the ion-damping rate and the ion-acoustic speed in plasmas. The effects of changing the ion-damping rate and ion-acoustic speed are investigated for electrostatic strong turbulence and electromagnetic strong turbulence in three dimensions. When ion damping is strong, density wells relax in place and act as nucleation sites for the formation of new wave packets. In this case, the density perturbations are primarily density wells supported by the ponderomotive force. For weak ion damping, corresponding to low Ti/Te, ion-acoustic waves are launched radially outwards when wave packets dissipate at burnout, thereby increasing the level of density perturbations in the system and thus raising the level of scattering of Langmuir waves off density perturbations. Density wells no longer relax in place so renucleation at recent collapse sites no longer occurs, instead wave packets form in background low density regions, such as superpositions of troughs of propagating ion-acoustic waves. This transition is found to occur at Ti/Te ? 0.1. The change in behavior with Ti/Te is shown to change the bulk statistical properties, scaling behavior, spectra, and field statistics of strong turbulence. For Ti/Te>rsim0.1, the electrostatic results approach the predictions of the two-component model of Robinson and Newman, and good agreement is found for Ti/Te>rsim0.15.

Graham, D. B.; Cairns, Iver H.; Skjaeraasen, O.; Robinson, P. A.

2012-02-01

326

RESEARCH ARTICLE A statistical downscaling scheme to improve global precipitation

RESEARCH ARTICLE A statistical downscaling scheme to improve global precipitation forecasting a statistical downscaling (SD) scheme suitable for global precipitation forecasting. The key idea of this SD indicates that current seasonal operational dynamical prediction has progressed significantly over past two

327

Topics in Statistical Mechanics: The Foundations of Molecular Simulation

Topics in Statistical Mechanics: The Foundations of Molecular Simulation J. Schofield/R. van ZonQuarrie, Statistical Mechanics Â· D. Frenkel and B. Smit, Understanding Molecular Dynamics: From Algorithms

Schofield, Jeremy

328

NASA Technical Reports Server (NTRS)

Non-Bayesian statistics were used in simulation studies centered around laser range observations to LAGEOS. The capabilities of satellite laser ranging especially in connection with relative station positioning are evaluated. The satellite measurement system under investigation may fall short in precise determinations of the earth's orientation (precession and nutation) and earth's rotation as opposed to systems as very long baseline interferometry (VLBI) and lunar laser ranging (LLR). Relative station positioning, determination of (differential) polar motion, positioning of stations with respect to the earth's center of mass and determination of the earth's gravity field should be easily realized by satellite laser ranging (SLR). The last two features should be considered as best (or solely) determinable by SLR in contrast to VLBI and LLR.

Vangelder, B. H. W.

1978-01-01

329

Statistical ecology comes of age.

The desire to predict the consequences of global environmental change has been the driver towards more realistic models embracing the variability and uncertainties inherent in ecology. Statistical ecology has gelled over the past decade as a discipline that moves away from describing patterns towards modelling the ecological processes that generate these patterns. Following the fourth International Statistical Ecology Conference (1-4 July 2014) in Montpellier, France, we analyse current trends in statistical ecology. Important advances in the analysis of individual movement, and in the modelling of population dynamics and species distributions, are made possible by the increasing use of hierarchical and hidden process models. Exciting research perspectives include the development of methods to interpret citizen science data and of efficient, flexible computational algorithms for model fitting. Statistical ecology has come of age: it now provides a general and mathematically rigorous framework linking ecological theory and empirical data. PMID:25540151

Gimenez, Olivier; Buckland, Stephen T; Morgan, Byron J T; Bez, Nicolas; Bertrand, Sophie; Choquet, Rémi; Dray, Stéphane; Etienne, Marie-Pierre; Fewster, Rachel; Gosselin, Frédéric; Mérigot, Bastien; Monestiez, Pascal; Morales, Juan M; Mortier, Frédéric; Munoz, François; Ovaskainen, Otso; Pavoine, Sandrine; Pradel, Roger; Schurr, Frank M; Thomas, Len; Thuiller, Wilfried; Trenkel, Verena; de Valpine, Perry; Rexstad, Eric

2014-12-01

330

Statistical ecology comes of age

The desire to predict the consequences of global environmental change has been the driver towards more realistic models embracing the variability and uncertainties inherent in ecology. Statistical ecology has gelled over the past decade as a discipline that moves away from describing patterns towards modelling the ecological processes that generate these patterns. Following the fourth International Statistical Ecology Conference (1–4 July 2014) in Montpellier, France, we analyse current trends in statistical ecology. Important advances in the analysis of individual movement, and in the modelling of population dynamics and species distributions, are made possible by the increasing use of hierarchical and hidden process models. Exciting research perspectives include the development of methods to interpret citizen science data and of efficient, flexible computational algorithms for model fitting. Statistical ecology has come of age: it now provides a general and mathematically rigorous framework linking ecological theory and empirical data. PMID:25540151

Gimenez, Olivier; Buckland, Stephen T.; Morgan, Byron J. T.; Bez, Nicolas; Bertrand, Sophie; Choquet, Rémi; Dray, Stéphane; Etienne, Marie-Pierre; Fewster, Rachel; Gosselin, Frédéric; Mérigot, Bastien; Monestiez, Pascal; Morales, Juan M.; Mortier, Frédéric; Munoz, François; Ovaskainen, Otso; Pavoine, Sandrine; Pradel, Roger; Schurr, Frank M.; Thomas, Len; Thuiller, Wilfried; Trenkel, Verena; de Valpine, Perry; Rexstad, Eric

2014-01-01

331

Quantum particles from classical statistics

Quantum particles and classical particles are described in a common setting of classical statistical physics. The property of a particle being "classical" or "quantum" ceases to be a basic conceptual difference. The dynamics differs, however, between quantum and classical particles. We describe position, motion and correlations of a quantum particle in terms of observables in a classical statistical ensemble. On the other side, we also construct explicitly the quantum formalism with wave function and Hamiltonian for classical particles. For a suitable time evolution of the classical probabilities and a suitable choice of observables all features of a quantum particle in a potential can be derived from classical statistics, including interference and tunneling. Besides conceptual advances, the treatment of classical and quantum particles in a common formalism could lead to interesting cross-fertilization between classical statistics and quantum physics.

C. Wetterich

2010-02-11

332

... MQSA) Scorecard Articles MQSA National Statistics MQSA National Statistics In this section of the MQSA Scorecard, we present the most commonly requested national statistics regarding the MQSA program. These statistics are updated ...

333

The method of least squares is probably the most powerful data analysis tool available to scientists. Toward a fuller appreciation of that power, this work begins with an elementary review of statistics fundamentals, and then progressively increases in sophistication as the coverage is extended to the theory and practice of linear and nonlinear least squares. The results are illustrated in application to data analysis problems important in the life sciences. The review of fundamentals includes the role of sampling and its connection to probability distributions, the Central Limit Theorem, and the importance of finite variance. Linear least squares are presented using matrix notation, and the significance of the key probability distributions-Gaussian, chi-square, and t-is illustrated with Monte Carlo calculations. The meaning of correlation is discussed, including its role in the propagation of error. When the data themselves are correlated, special methods are needed for the fitting, as they are also when fitting with constraints. Nonlinear fitting gives rise to nonnormal parameter distributions, but the 10% Rule of Thumb suggests that such problems will be insignificant when the parameter is sufficiently well determined. Illustrations include calibration with linear and nonlinear response functions, the dangers inherent in fitting inverted data (e.g., Lineweaver-Burk equation), an analysis of the reliability of the van't Hoff analysis, the problem of correlated data in the Guggenheim method, and the optimization of isothermal titration calorimetry procedures using the variance-covariance matrix for experiment design. The work concludes with illustrations on assessing and presenting results. PMID:17964948

Tellinghuisen, Joel

2008-01-01

334

Assessment of Statistical Downscaling of GCM Projections

., Lynn, B. and Goldberg, R. (2007). A comparison of statistical and dynamical downscaling for surfaceAssessment of Statistical Downscaling of GCM Projections for Water Resource Applications Amy to simulate the climate on Earth Â· What is downscaling? A method of processing the coarse information from

Mountziaris, T. J.

335

Conditional Statistics of Interdependent, Terascale Turbulence Data

Conditional Statistics of Interdependent, Terascale Turbulence Data Amanda Pellerite University and implementation of computational statistical tools to explore the dynamics of a fully developed 'wake' in a 3D turbulent fluid flow. Complications arise not only with examining the chaotic nature of turbulence, but also

Mountziaris, T. J.

336

Statistical Energy Analysis 2 Long. 3 Long.

Dynamics Â Signal Analysis Â Energy Flow in Built-up Systems Â Modal Analysis Â Energy Considerations1 Statistical Energy Analysis 1 2 3 1 Long. 1 Bend. 2 Long. 3 Long. 2 Bend. 3 Bend. [E] = [C]-1[W] Â© Prof. B.A.T. Petersson Statistical Energy Analysis Â· Lectures Â Time: Wednesday 10 - 12 Â Place: TA 201

Berlin,Technische UniversitÃ¤t

337

BOOK REVIEW: Statistical Mechanics of Turbulent Flows

This is a handbook for a computational approach to reacting flows, including background material on statistical mechanics. In this sense, the title is somewhat misleading with respect to other books dedicated to the statistical theory of turbulence (e.g. Monin and Yaglom). In the present book, emphasis is placed on modelling (engineering closures) for computational fluid dynamics. The probabilistic (pdf) approach

S. Heinz

2004-01-01

338

Statistical dependency in visual scanning

NASA Technical Reports Server (NTRS)

A method to identify statistical dependencies in the positions of eye fixations is developed and applied to eye movement data from subjects who viewed dynamic displays of air traffic and judged future relative position of aircraft. Analysis of approximately 23,000 fixations on points of interest on the display identified statistical dependencies in scanning that were independent of the physical placement of the points of interest. Identification of these dependencies is inconsistent with random-sampling-based theories used to model visual search and information seeking.

Ellis, Stephen R.; Stark, Lawrence

1986-01-01

339

Statistical trajectory models for phonetic recognition

The main goal of this work is to develop an alternative methodology for acoustic--phonetic modelling of speech sounds. The approach utilizes a segment--based frameworkto capture the dynamical behavior and statistical dependencies of the acousticattributes used to represent the speech waveform. Temporal behavior is modelledexplicitly by creating dynamic tracks of the acoustic attributes used to represent thewaveform, and by estimating the

William David Goldenthal; James R. Glass

1994-01-01

340

Statistical physics ""Beyond equilibrium

The scientific challenges of the 21st century will increasingly involve competing interactions, geometric frustration, spatial and temporal intrinsic inhomogeneity, nanoscale structures, and interactions spanning many scales. We will focus on a broad class of emerging problems that will require new tools in non-equilibrium statistical physics and that will find application in new material functionality, in predicting complex spatial dynamics, and in understanding novel states of matter. Our work will encompass materials under extreme conditions involving elastic/plastic deformation, competing interactions, intrinsic inhomogeneity, frustration in condensed matter systems, scaling phenomena in disordered materials from glasses to granular matter, quantum chemistry applied to nano-scale materials, soft-matter materials, and spatio-temporal properties of both ordinary and complex fluids.

Ecke, Robert E [Los Alamos National Laboratory

2009-01-01

341

Renyi statistics in equilibrium statistical mechanics

The Renyi statistics in the canonical and microcanonical ensembles is examined in the general case and in particular for the ideal gas. In the microcanonical ensemble the Renyi statistics is equivalent with the Boltzmann-Gibbs statistics. By the exact analytical results for the ideal gas, it is shown that in the canonical ensemble in the thermodynamic limit the Renyi statistics is also equivalent with the Boltzmann-Gibbs statistics. Furthermore it satisfies the requirements of the equilibrium thermodynamics, i.e. the thermodynamical potential of the statistical ensemble is a homogeneous function of degree 1 of its extensive variables of state. We conclude that the Renyi statistics duplicates the thermodynamical relations stemming from the Boltzmann-Gibbs statistics in the thermodynamical limit.

A. S. Parvan; T. S. Biro

2009-10-16

342

FISHERY STATISTICS UNITED STATES

FISHERY STATISTICS OF THE UNITED STATES 1972 STATISTICAL DIGEST NO. 66 Prepared by STATISTICS;ACKNOWLEDGMENTS The data in this edition of "Fishery Statistics of the United States" were collected in co- operation with the various States and tabulated by the staff of the Statistics and Market News Division

343

be classified into two types: dynamical downscaling and statistical downscaling. The method of dynamical down, the statistical downscaling method tends to be more straightforward than dynamical downscaling. And it can alsoA Statistical Downscaling Model for Forecasting Summer Rainfall in China from DEMETER Hindcast

344

NASA Astrophysics Data System (ADS)

The emplacement of magma-filled dikes often induce abundant seismicity in the surrounding host rocks. Most of the earthquakes are thought to occur close to the propagating tip (or edges, in 3D) of the dike, where stresses are concentrated. The resulting seismicity often appears as a swarm, controlled mainly by dike-induced stresses and stressing rate and by other factors, such as the background stressing rate, tectonic setting, regional stresses and tectonic history. The spatial distribution and focal mechanisms of the seismicity bear information on the interaction of the dike stress field and the tectonic setting of the area. The seismicity accompanying the intrusion of a dike is usually characterized by weak events, for which it is difficult to calculate the focal mechanisms. Therefore, only for a few well-recorded dike intrusions a catalog of focal mechanisms, allowing to perform a robust statistical analysis, is available. The 2000 dike intrusion at Miyakejima is in this sense an outstanding case, as about 18000 seismic events were recorded in a time span of three months. This seismic swarm was one of the most energetic ever recorded with five M>6 earthquakes. For this swarm a catalog of 1500 focal mechanisms is avalable (NIED, Japan). We perform a clustering analysis of the focal mechanism solutions, in order to infer the most frequent focal mechanism features prior to the intrusion (pre-diking period) and during the co-diking period. As previously suggested, we find that the dike stress field modified substantially the pre-existing seismicity pattern, by shadowing some non-optimally oriented strike-slip structures and increasing seismic rate on optimally oriented strike-slip tectonic structures. Alongside, during the co-diking period a large number of normal and oblique-normal faulting were observed. These events cannot be explained within the tectonics of the intrusion area. We suggest they are directly generated by the intense stress field induced at the dike edges. We further investigate the distribution of the two main clusters we identify, i.e. strike-slip and oblique-normal mechanisms. We find that the strike-slip family obeys a Gutenberg-Richter law with a b-value close to one. The oblique-normal family of events deviates from the Gutenberg-Richter distribution and is slightly bimodal, with a marked roll-off on its right-hand tail suggesting a lack of large magnitude events (M>5.5). This set of events seems to collect earthquakes rupturing above the dike, similar to graben faulting events widely observed in volcanic areas during diking. A possible explanation of the anomalous frequency-magnitude distribution is that these earthquakes may be limited in size by the thickness of the layer where they nucleate, being spatially constrained between the dike upper edge and the Earth's surface.

Passarelli, Luigi; Rivalta, Eleonora; Simone, Cesca; Aoki, Yosuke

2014-05-01

345

Statistical validation of stochastic models

It is common practice in structural dynamics to develop mathematical models for system behavior, and the authors are now capable of developing stochastic models, i.e., models whose parameters are random variables. Such models have random characteristics that are meant to simulate the randomness in characteristics of experimentally observed systems. This paper suggests a formal statistical procedure for the validation of mathematical models of stochastic systems when data taken during operation of the stochastic system are available. The statistical characteristics of the experimental system are obtained using the bootstrap, a technique for the statistical analysis of non-Gaussian data. The authors propose a procedure to determine whether or not a mathematical model is an acceptable model of a stochastic system with regard to user-specified measures of system behavior. A numerical example is presented to demonstrate the application of the technique.

Hunter, N.F. [Los Alamos National Lab., NM (United States). Engineering Science and Analysis Div.; Barney, P.; Paez, T.L. [Sandia National Labs., Albuquerque, NM (United States). Experimental Structural Dynamics Dept.; Ferregut, C.; Perez, L. [Univ. of Texas, El Paso, TX (United States). Dept. of Civil Engineering

1996-12-31

346

Arthritis: Data and Statistics

... About CDC.gov . Arthritis Share Compartir Data and Statistics National Statistics Based on 2010-2012 data from the National ... survey conducted by the National Center for Health Statistics. Each year, the NHIS samples U.S. households and ...

347

Neuroendocrine Tumor: Statistics

... Statistics Request Permissions Print to PDF Neuroendocrine Tumor: Statistics This section has been reviewed and approved by ... nodes or distant parts of the body. Survival statistics should be interpreted with caution. These estimates are ...

348

... at NIMH News About Us Home > Health & Education Statistics Prevalence Disability Suicide Cost Global More Prevalence Disability ... those affected receive treatment. The information on these statistics pages includes the best statistics currently available on ...

349

NASA Astrophysics Data System (ADS)

Empirical Potential Molecular Dynamics (EPMD) simulations have been carried out for molten MgSiO3, Mg2SiO4, CaMgSi2O6, CaAl2Si2O8 and 1-bar eutectic liquid in the binary system CaMgSi2O6-CaAl2Si2O8 using a Coulomb-Born-Mayer-van der Waals pair potential form and the potential parameters from Matsui (1996, GRL 23:395) for the system CaO-MgO-Al2O3-SiO2. Simulations were performed in the microcanonical ensemble (NEV) with 8000 atoms, a 1 fs time step, and simulation durations up to 2 ns. Computations were carried out every 500 K over a temperature range of 2500 - 5000 K along 10-20 isochores for each composition to insure good coverage in P-T space. During run T and P fluctuations, giving the uncertainty of state point coordinates was typically ± 30 K and ± 0.5 GPa, respectively. Coordination statistics are determined by counting nearest neighbor configurations up to a cutoff defined by the first minima of the pair correlation function. A complete set of coordination statistics was collected at each state point for each composition. At each state point self-diffusivity of each atom was determined from the Einstein relation between Mean Square Displacement and time. Shear viscosity was computed for a subset of state points using Green-Kubo linear response theory, by studying the autocorrelated regressions of spontaneous fluctuations of appropriate components of the stress tensor. Thermodynamic models (and EOS) for each liquid previously developed from these simulations based on combining the Rosenfeld-Tarazona (1998, Mol Phys 95:141) potential energy-temperature scaling law with the Universal EOS (1986, J Phys C, 19:L467) enable self-consistent computation of liquid sound speeds and isochoric heat capacity used to develop phonon thermal conductivity values at high T and P. Self-diffusivity, shear viscosity and phonon thermal conductivity values from the MD simulations vary systematically with composition, temperature and pressure. These systematic relations correlate with and can be modeled from average first nearest neighbor mean coordination numbers especially for Si and Al around oxygen, oxygen around oxygen, and Ca and Mg around oxygen. Generalized versions of the Stokes-Einstein and Eyring relationships connecting self-diffusivity of oxygen to liquid shear viscosity, T and a characteristic length scale based on coordination statistics can be constructed from MD generated transport properties to capture laboratory data reasonably well in many instances.

Spera, F. J.; Martin, B.; Creamer, J. B.; Nevins, D.; Cutler, I.; Ghiorso, M. S.; Tikunoff, D.

2010-12-01

350

Statistics (Program Description)

... for developing and improving statistical theory and methods, including research in statistical ... Supported areas include frequentist and Bayesian inference in parametric, semi-parametric, and ...

351

9. Statistical Energy Analysis (SEA) 80 9. Statistical Energy Analysis (SEA)

9. Statistical Energy Analysis (SEA) 80 _____________________________________________________________________________ 9. Statistical Energy Analysis (SEA) 9.1 Introduction In this chapter an introduction to a framework for the analysis of the dynamics of complex, built-up structural and fluid systems will be outlined. This framework

Berlin,Technische UniversitÃ¤t

352

Statistical properties of cosmological billiards

Belinski, Khalatnikov, and Lifshitz pioneered the study of the statistical properties of the never-ending oscillatory behavior (among successive Kasner epochs) of the geometry near a spacelike singularity. We show how the use of a 'cosmological billiard' description allows one to refine and deepen the understanding of these statistical properties. Contrary to previous treatments, we do not quotient the dynamics by its discrete symmetry group (of order 6), thereby uncovering new phenomena, such as correlations between the successive billiard corners in which the oscillations take place. Starting from the general integral invariants of Hamiltonian systems, we show how to construct invariant measures for various projections of the cosmological-billiard dynamics. In particular, we exhibit, for the first time, a (non-normalizable) invariant measure on the 'Kasner circle' which parametrizes the exponents of successive Kasner epochs. Finally, we discuss the relation between: (i) the unquotiented dynamics of the Bianchi-IX (a, b, c or mixmaster) model; (ii) its quotienting by the group of permutations of (a, b, c); and (iii) the billiard dynamics that arose in recent studies suggesting the hidden presence of Kac-Moody symmetries in cosmological billiards.

Damour, Thibault [Institut des Hautes Etudes Scientifiques, 35, route de Chartres, 91440 Bures-sur-Yvette (France); ICRANet, Pescara (Italy); Lecian, Orchidea Maria [Institut des Hautes Etudes Scientifiques, 35, route de Chartres, 91440 Bures-sur-Yvette (France); ICRANet, Pescara (Italy); APC, UMR 7164 du CNRS, Universite Paris 7, 10, rue A. Domon et L. Duquet, 75205 Paris Cedex 13 (France)

2011-02-15

353

American Statistical Association: Statistics in Sports

NSDL National Science Digital Library

This section of the American Statistical Association website covers Statistics in Sports. Available here are a few older articles dealing with sports statistics and links to websites containing data for several professional and amateur sports, as well as websites with general news and information about sports, and a listing of official team websites for pro teams. A section called Statistics on the Web provides links to academic departments, conferences, and employers, while another section answers some frequently asked questions about sports statistics as a career. The website also provides an explanation of the Player Game Percentage (PGP) technique and uses the 2004 World Series as an example to demonstrate the technique. Educators will find a link to a website that offers suggestions of ways to incorporate sports statistics in the classroom.

354

Statistical Reference Datasets

National Institute of Standards and Technology Data Gateway

Statistical Reference Datasets (Web, free access) The Statistical Reference Datasets is also supported by the Standard Reference Data Program. The purpose of this project is to improve the accuracy of statistical software by providing reference datasets with certified computational results that enable the objective evaluation of statistical software.

355

Sampling in Statistical Inference

NSDL National Science Digital Library

This site, presented by the Department of Statistics at Yale University, gives an explanation, a definition and an example of sampling in statistical inference. Topics include parameters, statistics, sampling distributions, bias, and variability. Overall, this is a great resource for any mathematics classroom studying statistics.

Lacey, Michelle

2008-12-23

356

International Statistical Institute - Glossary of Statistical Terms

NSDL National Science Digital Library

This site shows the International Statistical Institutes alphabetical list of technical terms showing the translation in a number of languages. The page covers a myriad of different terms and our translated into many languages such as: English, French, German, Dutch, Italian, Spanish, Catalan, Portuguese, Romanian, Danish, Norwegian, Swedish, Greek and many more. This is a nice reference site for anyone interested in statistics.

357

Equilibrium statistical mechanics for incomplete nonextensive statistics

The incomplete nonextensive statistics in the canonical and microcanonical ensembles is explored in the general case and in a particular case for the ideal gas. By exact analytical results for the ideal gas it is shown that taking the thermodynamic limit, with $z=q/(1-q)$ being an extensive variable of state, the incomplete nonextensive statistics satisfies the requirements of equilibrium thermodynamics. The thermodynamical potential of the statistical ensemble is a homogeneous function of the first degree of the extensive variables of state. In this case, the incomplete nonextensive statistics is equivalent to the usual Tsallis statistics. If $z$ is an intensive variable of state, i.e. the entropic index $q$ is a universal constant, the requirements of the equilibrium thermodynamics are violated.

A. S. Parvan; T. S. Biro

2010-03-29

358

Statistical dynamics of early river networks

NASA Astrophysics Data System (ADS)

Based on local erosion rule and fluctuations in rainfall, geology and parameters of a river channel, a generalized Langevin equation is proposed to describe the random prolongation of a river channel. This equation is transformed into the Fokker-Plank equation to follow the early evolution of a river network and the variation of probability distribution of channel lengths. The general solution of the equation is in the product form of two terms. One term is in power form and the other is in exponent form. This distribution shows a complete history of a river network evolving from its infancy to “adulthood”). The infancy is characterized by the Gaussian distribution of the channel lengths, while the adulthood is marked by a power law distribution of the channel lengths. The variation of the distribution from the Gaussian to the power law displays a gradual developing progress of the river network. The distribution of basin areas is obtained by means of Hack's law. These provide us with new understandings towards river networks.

Wang, Xu-Ming; Wang, Peng; Zhang, Ping; Hao, Rui; Huo, Jie

2012-10-01

359

R\\/S Statistic: Accuracy and Implementations

The paper studies the behaviour of three different R\\/S statistic algorithms for Hurst-index estimation in self-similar and long-range dependent discrete time series. The accuracy of the algorithms under convergence and aggregation in time is obtained and compared. The results show that static blocks implementations of the R\\/S statistic present better accuracy than those based on a dynamic blocks implementation. The

Julio C. Ramirez Pacheco; Deni Torres Roman; Leopoldo Estrada Vargas

2008-01-01

360

Accelerated molecular dynamics methods

The molecular dynamics method, although extremely powerful for materials simulations, is limited to times scales of roughly one microsecond or less. On longer time scales, dynamical evolution typically consists of infrequent events, which are usually activated processes. This course is focused on understanding infrequent-event dynamics, on methods for characterizing infrequent-event mechanisms and rate constants, and on methods for simulating long time scales in infrequent-event systems, emphasizing the recently developed accelerated molecular dynamics methods (hyperdynamics, parallel replica dynamics, and temperature accelerated dynamics). Some familiarity with basic statistical mechanics and molecular dynamics methods will be assumed.

Perez, Danny [Los Alamos National Laboratory

2011-01-04

361

Population dynamics in meerkats, Suricata suricatta

mathematical and statistical models, in conjunction with long-term data from a wild meerkat population, to explore population dynamics, group dynamics, group demography, Allee effects, and territory dynamics in this species. I start out by examining broad...

Bateman, Andrew

2013-03-12

362

Introductory statistical mechanics for electron storage rings

These lectures introduce the beam dynamics of electron-positron storage rings with particular emphasis on the effects due to synchrotron radiation. They differ from most other introductions in their systematic use of the physical principles and mathematical techniques of the non-equilibrium statistical mechanics of fluctuating dynamical systems. A self-contained exposition of the necessary topics from this field is included. Throughout the development, a Hamiltonian description of the effects of the externally applied fields is maintained in order to preserve the links with other lectures on beam dynamics and to show clearly the extent to which electron dynamics in non-Hamiltonian. The statistical mechanical framework is extended to a discussion of the conceptual foundations of the treatment of collective effects through the Vlasov equation.

Jowett, J.M.

1986-07-01

363

... About Blood > Blood Facts and Statistics Printable Version Blood Facts and Statistics Facts about blood needs Facts ... about American Red Cross Blood Services Facts about blood needs Every two seconds someone in the U.S. ...

364

Developments in Statistical Education.

ERIC Educational Resources Information Center

The current status of statistics education at the secondary level is reviewed, with particular attention focused on the various instructional programs in England. A description and preliminary evaluation of the Schools Council Project on Statistical Education is included. (MP)

Kapadia, Ramesh

1980-01-01

365

... updates Please leave this field empty Brain Tumor Statistics SHARE Share on Facebook Preview your comments Share ... Close Finish Home > About Us > News > Brain Tumor Statistics Listen Brain Tumors do not discriminate. Primary brain ...

366

... Research AMIGAS Fighting Cervical Cancer Worldwide Stay Informed Statistics for Other Kinds of Cancer Breast Cervical Colorectal ( ... Skin Vaginal and Vulvar Cancer Home Uterine Cancer Statistics Language: English Español (Spanish) Share Compartir Uterine cancer ...

367

... page: About CDC.gov . Hemophilia Share Compartir Data & Statistics In the United States [ Read article ] Hemophilia affects ... HTC Directory Update Contact Info (Password Required) Data & Statistics Training & Education Research CHAMP Universal Data Collection Blood ...

368

Valley Fever (Coccidioidomycosis) Statistics

... gov . Fungal Diseases Share Compartir Valley Fever (Coccidioidomycosis) Statistics How common is valley fever? In states where ... Risk & Prevention Sources Diagnosis & Testing Treatment Health Professionals Statistics More Resources Blastomycosis Definition Symptoms People at Risk & ...

369

Pneumocystis Pneumonia Statistics

... CDC.gov . Fungal Diseases Share Compartir Pneumocystis pneumonia Statistics Before the beginning of the HIV/AIDS epidemic ... Risk & Prevention Sources Diagnosis & Testing Treatment Health Professionals Statistics More Resources Blastomycosis Definition Symptoms People at Risk & ...

370

Listeria (Listeriosis) Statistics

... page: About CDC.gov . Listeria (Listeriosis) Share Compartir Statistics Estimates CDC estimates that approximately 1600 illnesses and ... 12, 2011 Case Count Map Epi Curve Surveillance Statistics People at Risk Prevention Sources of Infection Diagnosis & ...

371

Immigration and Naturalization Statistics

NSDL National Science Digital Library

The Immigration and Naturalizations Service Statistics site provides "comprehensive annual immigration statistics from 1994-1996, as well as state estimates of the United States' illegal alien resident and foreign-born populations."

Service., United S.

1997-01-01

372

Interpreting Accident Statistics

Accident statistics have often been used to support the argument that an abnormally small proportion of drivers account for a large proportion of the accidents. This paper compares statistics developed from six-year data ...

Ferreira, Joseph Jr.

373

This document provides guidance for using the ACS Statistical Analyzer. It is an Excel-based template for users of estimates from the American Community Survey (ACS) to assess the precision of individual estimates and to compare pairs of estimates for their statistical differences. The ACS Statistical Analyzer covers the following four functions and fifteen sub-functions (not listed): (1) To derive other

Xuehao Chu

2010-01-01

374

Defines common statistical terms, NCI terminology, and the five key statistical measures of cancer: incidence, mortality, survival, prevalence, and lifetime risk. NCI monitors these cancer statistics to assess progress and to identify population subgroups and geographic areas in which cancer control efforts need to be concentrated.

375

Giovanni Gallavotti STATISTICAL MECHANICS

Giovanni Gallavotti STATISTICAL MECHANICS Short Treatise Roma 1999 #12; . #12; Short treatise of Statistical Mechanics Giovanni Gallavotti Dipartimento di Fisica Universitâ??a di Roma La Sapienza 00185 Roma that started with my involvement as Coordinator of the Statistical Mechanics section of the Italian Encyclo

Roma "La Sapienza", UniversitÃ di

376

Statistical Mechanics its applications

Statistical Mechanics and its applications Dr A. Alavi Part II Chemistry 2007-2008 1 #12;I. INTRODUCTION Statistical Mechanics is concerned with how to describe the behaviour of systems containing large, and how this is done, as well as its theoretical justification, is the subject of Statistical Mechanics. A

Alavi, Ali

377

Giovanni Gallavotti STATISTICAL MECHANICS

Giovanni Gallavotti STATISTICAL MECHANICS Short Treatise Roma 1999 #12;. #12;Short treatise of Statistical Mechanics Giovanni Gallavotti Dipartimento di Fisica Universit`a di Roma La Sapienza 00185 Roma that started with my involvement as Coordinator of the Statistical Mechanics section of the Italian Encyclo

Roma "La Sapienza", UniversitÃ di

378

Statistics Statistique Canada Canada

Statistics Statistique Canada Canada Human Resources and Ressources humaines et Skills Development Canada DÃ©veloppement des compÃ©tences Canada Culture,Tourism and the Centre for Education Statistics about this product or the wide range of services and data available from Statistics Canada, visit our

Sinnamon, Gordon J.

379

Applied Statistics Spring 2010

, statistical process control, contingency tables and nonparametric methods. Use of statistical computer package Statistical process control 17.1-17.5 11 12 Chi-square tests and Contingency tables 10.14-10.16 12 13 Â· Design of experiments Â· Analysis of variance (ANOVA) Â· Analysis of discrete data (contingency tables

Langseth, Helge

380

Statistical Abstract: USA Statistics in Brief

NSDL National Science Digital Library

This web page, authored by the United State Census Bureau, contains statistics about the current population. Some of these statistics include: sex, age, state population, births, deaths, households, housing, construction, education, government, social welfare, law enforcement, employment, income, poverty, prices, energy, transportation, communications, agriculture, business, finance and foreign commerce. As demonstrated this is a fairly comprehensive data set. The sets are contained in both html or Excel format.

2009-02-09

381

Introduction to Statistics 1.1 What is statistics?

facts: Social statistics, sports statistics, crime statistics. (2) Field or discipline of study: That is) Inferential statistics consists of methods that use sample results to help make decisions or predictions aboutChapter 1 Introduction to Statistics 1.1 What is statistics? Statistics means numerical

Cho, Hokwon

382

Statistical Convergence and Convergence in Statistics

Statistical convergence was introduced in connection with problems of series summation. The main idea of the statistical convergence of a sequence l is that the majority of elements from l converge and we do not care what is going on with other elements. We show (Section 2) that being mathematically formalized the concept of statistical convergence is directly connected to convergence of such statistical characteristics as the mean and standard deviation. At the same time, it known that sequences that come from real life sources, such as measurement and computation, do not allow, in a general case, to test whether they converge or statistically converge in the strict mathematical sense. To overcome limitations induced by vagueness and uncertainty of real life data, neoclassical analysis has been developed. It extends the scope and results of the classical mathematical analysis by applying fuzzy logic to conventional mathematical objects, such as functions, sequences, and series. The goal of this work is the further development of neoclassical analysis. This allows us to reflect and model vagueness and uncertainty of our knowledge, which results from imprecision of measurement and inaccuracy of computation. In the context on the theory of fuzzy limits, we develop the structure of statistical fuzzy convergence and study its properties.

Mark Burgin; Oktay Duman

2006-12-07

383

Statistical mechanics of violent relaxation

NASA Technical Reports Server (NTRS)

We propose a functional that is extremized through violent relaxation. It is based on the Ansatz that the wave-particle scattering during violent dynamical processes can be approximated as a sequence of discrete scattering events that occur near a particle's perigalacticon. This functional has an extremum whose structure closely resembles that of spheroidal stellar systems such as elliptical galaxies. The results described here, therefore, provide a simple framework for understanding the physical nature of violent relaxation and support the view that galaxies are structured in accord with fundamental statistical principles.

Spergel, David N.; Hernquist, Lars

1992-01-01

384

Nonstationary statistical theory for multipactor

This work presents a new and general approach to the real dynamics of the multipactor process: the nonstationary statistical multipactor theory. The nonstationary theory removes the stationarity assumption of the classical theory and, as a consequence, it is able to adequately model electron exponential growth as well as absorption processes, above and below the multipactor breakdown level. In addition, it considers both double-surface and single-surface interactions constituting a full framework for nonresonant polyphase multipactor analysis. This work formulates the new theory and validates it with numerical and experimental results with excellent agreement.

Anza, S.; Vicente, C.; Gil, J. [Aurora Software and Testing S.L., Edificio de Desarrollo Empresarial 9B, Universidad Politecnica de Valencia, Camino de Vera s/n, 46022 Valencia (Spain); Boria, V. E. [Departamento de Comunicaciones-iTEAM, Universidad Politecnica de Valencia, Camino de Vera s/n, 46022 Valencia (Spain); Gimeno, B. [Departamento de Fisica Aplicada y Electromagnetismo-ICMUV, Universitat de Valencia, c/Dr. Moliner, 50, 46100 Valencia (Spain); Raboso, D. [Payloads Systems Division, European Space Agency, 2200-AG Noordwijk (Netherlands)

2010-06-15

385

Statistical Inference in Inverse Problems

in developing efficient estimation methods for such problems. Various statistical methods have been developed to estimate parameters in or- dinary differential equation (ODE) models. There is a series of work in the study of HIV dynamics in order... to understand the pathogenesis of HIV infection. For ex- ample, Ho et al. (1995) and Wei et al. (1995) used standard nonlinear least square regression methods; Wu, Ding and DeGruttola (1998) and Wu and Ding (1999) first proposed a mixed-effects model approach...

Xun, Xiaolei

2012-07-16

386

Statistical Characteristics of Earthquake Ground Motion;

Statistical Characteristics of Earthquake Ground Motion; Has PBEE Broken the Power Law? Tom Heaton Â· Currently the Director of the Earthquake Engineering Research Laboratory (EERL) Â· BS in physics from Indiana Dynamics and most of my students are EE Â· Not your typical Earthquake Engineer #12;Caltech asked me

Greer, Julia R.

387

STATWIZ - AN ELECTRONIC STATISTICAL TOOL (ABSTRACT)

StatWiz is a web-based, interactive, and dynamic statistical tool for researchers. It will allow researchers to input information and/or data and then receive experimental design options, or outputs from data analysis. StatWiz is envisioned as an expert system that will walk rese...

388

BS in STATISTICS: Statistical Science Emphasis (695220) MAP Sheet Department of Statistics

BS in STATISTICS: Statistical Science Emphasis (695220) MAP Sheet Department of Statistics the following: Stat 121 Principles of Statistics Stat 151 Introduction to Bayesian Statistics Stat 201 Statistics for Engineers & Scientists Stat 301 Statistics & Probability for Sec Ed Note: Students who have

Olsen Jr., Dan R.

389

Springer Series in Statistics Springer Series in Statistics

Springer Series in Statistics Springer Series in Statistics Inference in Hidden Markov Models class of statistical models with applications in diverse areas such as communications engineering models, including both algo- rithms and statistical theory. Topics range from filtering and smoothing

CappÃ©, Olivier

390

This article presents a general and versatile methodology for assessing sustainability with Fisher Information as a function of dynamic changes in urban systems. Using robust statistical methods, six Metropolitan Statistical Areas (MSAs) in Ohio were evaluated to comparatively as...

391

1 Statistics Statistics plays an important role throughout society, providing

1 Statistics STATISTICS Statistics plays an important role throughout society, providing data. They also explore how those skills can be applied to develop new initiatives. Statistics is one. UNDERGRADUATE Bachelor's program Â· Bachelor of Science with a major in statistics (http:// bulletin.gwu.edu/arts-sciences/statistics

Vertes, Akos

392

NSDL National Science Digital Library

This Website, maintained by Carlos Herrera of the Donana Biological Station in Seville, Spain, is "a collection of links to sites with mathematical and statistical material (software, documents) which may be useful to ecologists and evolutionary ecologists." Organized into eight sections, the site points users to resources from Ecologically-oriented software to General Statistical Libraries. For graduate students and researchers alike, this statistics resource is sure to come in handy.

393

NSDL National Science Digital Library

This site, by SPSS statistician Clay Helberg, is a broad resource containing statistical information, brief descriptions of professional organizations, lists of email discussion groups, and links to online textbooks and courses. The heart of the site is the Educational Resources section, which offers links to valuable Websites that describe and demonstrate statistical techniques. For graduate students and researchers alike, this statistics resource is sure to come in handy.

394

NSDL National Science Digital Library

Statistics play a vital role in the scientific enterprise. This activity provides background information and tutorials on basic statistics (mean, median, standard deviation, etc.) used in science. Topics include descriptive statistics (measures of central tendency and dispersion) and presenting data (tables, figures, and graphs). Sample datasets from actual scientific experiments are used to illustrate points. Links to an online statisitical tool and an online graphing application are also provided.

Laposata, Matt

395

NSDL National Science Digital Library

The 1998 issue of this annual United States Department of Agriculture National Agricultural Statistics Service compendium is available (Adobe Acrobat [.pdf] format only) from the Agricultural Statistics site. Its fifteen chapters consist of time series tables covering all aspects of the US agricultural economy, including crops, livestock, farm income and expenses, price-support, and fertilizer and pesticides. Time series and geographic coverage vary. The site also contains national and state tables and an archive of Agricultural Statistics back to 1994.

396

NSDL National Science Digital Library

Statistical Process Control is a lesson plan which provides an overview of Statistical Process Control, showing the value of collecting and analyzing data that enables people to systematically analyze and improve a process. After completing this module, students should be able to construct and interpret different statistical charts in order to evaluate a process. Note: This module is part of a modularized manufacturing technology curriculum created by the PSCME, found at www.pscme.org/educators.html.

Devine, Craig; Imre, John; King, John

2010-09-02

397

Visualization of Statistical Contents.

?? Our project presents the research on visualization of statistical contents. Here wewill introduce the concepts of visualization, software quality metrics andproposed visualization technique (line… (more)

MEHMOOD, RAJA MAJID

2009-01-01

398

Visualization of Statistical Contents.

?? Our project presents the research on visualization of statistical contents. Here wewill introduce the concepts of visualization, software quality metrics andproposed visualization technique (line… (more)

Mehmood, Raja Majid

2010-01-01

399

Statistics Canada = Statistique Canada

NSDL National Science Digital Library

Statistics Canada, a national statistical agency, offers this excellent collection on the economic and social conditions in Canada. Statistical information is divided into four broad topics: The Land, The People, The Economy, and the State. Within each are a number of sub-topics which offer lists of statistical tables. Newly released data, research papers, downloadable publications (Adobe Acrobat [.pdf] format only), and notices of seminars and conferences are featured in addition to The Daily, a collection of the latest news releases and publications from the agency. This site can be viewed in English or French. Note that there is a combination of free and fee based material available.

1997-01-01

400

Federal Law Enforcement Statistics

NSDL National Science Digital Library

Supplies census statistics about federal employees with law enforcement authority. Provides additional information about the functionality, budget, expenditures, and staffing of federal crime labs and police departments.

U.S. Department of Justice

401

Heat equation and Non-equilibrium (Classical) Statistical Mechanics

. Now assume (Fourier Law) j = k u, then tu = div(k u) 2 #12;But Ludwig Eduard Boltzmann (1844 Â1906-equilibrium Statistical Mechanics and Dynamical Systems (Sinai, Ruelle, Gallavotti, .....) Kinetic limit and Boltzmann

Liverani, Carlangelo

402

Adoption and Foster Care Statistics

... Research » Adoption & Foster Care Statistics Adoption & Foster Care Statistics Listen The Adoption and Foster Care Analysis and ... accurately. State-by-State Adoption and Foster Care Statistics State-Specific Adoption Statistics 2013 2012 2011 2010 ...

403

Geophysical Fluid Dynamics Laboratory Review May 20 May 22, 2014

downscaling for regional climate Keith W. Dixon #12;Geophysical Fluid Dynamics Laboratory Review May 20Geophysical Fluid Dynamics Laboratory Review May 20 Â May 22, 2014 Presented by Statistical-22, 2014 What is statistical downscaling? (aka empirical statistical downscaling or ESD) A statistical

404

Stellar Evolution A Statistical Model

Stellar Evolution A Statistical Model Statistical Computation Analysis of the Hyades Cluster Statistical Analysis of Stellar Evolution David A. van Dyk1 Steven DeGennaro2 Nathan Stein2 William H Statistical Analysis of Stellar Evolution #12;Stellar Evolution A Statistical Model Statistical Computation

van Dyk, David

405

R for Statistics Rafal Kulik Department of Mathematics and Statistics University of Ottawa Statistical Society of Ottawa 23 September 2011 Rafal Kulik #12;R for Statistics SSO meeting Plan Rafal Kulik 1 #12;R for Statistics SSO meeting Plan What is R? Rafal Kulik 1 #12;R for Statistics SSO meeting

Kulik, Rafal

406

On non-extensive statistics, chaos and fractal strings

Motivated by the growing evidence of universality and chaos in QFT and string theory, we study the Tsallis non-extensive statistics (with a non-additive q-entropy) of an ensemble of fractal strings and branes of different dimensionalities. Non-equilibrium systems with complex dynamics in stationary states may exhibit large fluctuations of intensive quantities which are described in terms of generalized statistics. Tsallis statistics

C. Castro

2005-01-01

407

Statistical Transmutation and Phases of Two-Dimensional Quantum Matter

After surveying the quantum kinematics and dynamics of statistical transmutation, I show how this concept suggests a phase diagram for the two-dimensional matter in a magnetic field, as a function of quantum statistics. I discuss the fundamental properties of quasiparticles in the different phases, and briefly suggest {\\it gedanken\\/} -- but not manifestly infeasible -- experiments to show up these properties.

Frank Wilczek

1995-09-14

408

Statistical effects in the multistream model for quantum plasmas

A statistical multistream description of quantum plasmas is formulated, using the Wigner-Poisson system as dynamical equations. A linear stability analysis of this system is carried out, and it is shown that a Landau-like damping of plane wave perturbations occurs due to the broadening of the background Wigner function that arises as a consequence of statistical variations of the wave function

Dan Anderson; Björn Hall; Mietek Lisak; Mattias Marklund

2002-01-01

409

Statistical Reference Datasets: Archives

NSDL National Science Digital Library

The datasets on this page are classified by analysis techniqueand by level of difficulty (lower, average, higher). They were originally intended to test statistical software. The sets cover these topics: ANOVA, linear regression, Markov Chain Monte Carlo, nonlinear regression, and univariate summary statistics. This is a nice collection as it not only contains raw data but also helps explain the different methods and tests.

410

NSDL National Science Digital Library

This site contains links in several statistical categories, including other meta-sites (catalogs), universities, statistics departments, software, journals, data sets, methodology, conferences, and teaching, among others. It has an Australian flavor, but is international in scope. Gordon K. Smyth, Research scientist and mathematician, maintains this site.

1998-01-01

411

Explorations in Statistics: Correlation

ERIC Educational Resources Information Center

Learning about statistics is a lot like learning about science: the learning is more meaningful if you can actively explore. This sixth installment of "Explorations in Statistics" explores correlation, a familiar technique that estimates the magnitude of a straight-line relationship between two variables. Correlation is meaningful only when the…

Curran-Everett, Douglas

2010-01-01

412

China's official poverty statistics show a dramatic reduction in poverty from 31% of the rural population in 1978 to 3% in 2000. We evaluate possible sources of bias in these estimates and conclude that the official statistics underestimate rural poverty and overstate the speed of poverty reduction. Direct measures of nutritional outcomes support the contention that poverty is more widespread

Albert PARKa

413

China's official poverty statistics show a dramatic reduction in poverty from 31% of the rural population in 1978 to 3% in 2000. We evaluate possible sources of bias in these estimates and conclude that the official statistics underestimate rural poverty and overstate the speed of poverty reduction. Direct measures of nutritional outcomes support the contention that poverty is more widespread

Albert Park; Sangui Wang

2001-01-01

414

Transportation Statistics Annual Report

NSDL National Science Digital Library

The US Department of Transportation's Bureau of Transportation Statistics provides Transportation Statistics Annual Report (TSAR), a companion to NTS, in Adobe Acrobat (.pdf) format, from 1994 to the present at this time. Transportation in the United States: A Review, summarizing these four reports, is also available.

415

NSDL National Science Digital Library

These pages from the University of Melbourne explain statistical concepts using various examples from medicine, science, sports, and finance. The intent is not computational skill but conceptual understanding. Some pages also contain data. This is a great example of how students can apply what they learn in the classroom to real world events. This is a great resource for any classroom studying statistics.

Malone, Fiona

416

Explorations in Statistics: Power

ERIC Educational Resources Information Center

Learning about statistics is a lot like learning about science: the learning is more meaningful if you can actively explore. This fifth installment of "Explorations in Statistics" revisits power, a concept fundamental to the test of a null hypothesis. Power is the probability that we reject the null hypothesis when it is false. Four things affect…

Curran-Everett, Douglas

2010-01-01

417

Reform in Statistical Education

ERIC Educational Resources Information Center

Two questions are considered in this article: (a) What should professionals in school psychology do in an effort to stay current with developments in applied statistics? (b) What should they do with their existing knowledge to move from surface understanding of statistics to deep understanding? Written for school psychologists who have completed…

Huck, Schuyler W.

2007-01-01

418

ERIC Educational Resources Information Center

Statistics on application and registration patterns of applicants wishing to pursue full-time study in first-year places in the Ontario universities were obtained throughout the admission cycle from the processing of applicants by the Center and from the universities themselves. All application and registration statistics presented refer to…

Payton, L. C.

419

ERIC Educational Resources Information Center

Summary statistics on application and registration patterns of applicants wishing to pursue full-time study in first-year places in Ontario universities (for the fall of 1987) are given. Data on registrations were received indirectly from the universities as part of their annual submission of USIS/UAR enrollment data to Statistics Canada and MCU.…

Council of Ontario Universities, Toronto.

420

Multidimensional Visual Statistical Learning

ERIC Educational Resources Information Center

Recent studies of visual statistical learning (VSL) have demonstrated that statistical regularities in sequences of visual stimuli can be automatically extracted, even without intent or awareness. Despite much work on this topic, however, several fundamental questions remain about the nature of VSL. In particular, previous experiments have not…

Turk-Browne, Nicholas B.; Isola, Phillip J.; Scholl, Brian J.; Treat, Teresa A.

2008-01-01

421

NSDL National Science Digital Library

The US Department of Labor Bureau of Labor Statistics collects "succinct, up-to-the-minute background papers on current topics" at the Issues in Labor Statistics publication page. Each two-page edition addresses labor topics as diverse as auto dealer employment and highway fatalities with graphical summaries and BLS contacts for additional information.

422

ERIC Educational Resources Information Center

Accessibly written and easy to use, "Applied Statistics Using SPSS" is an all-in-one self-study guide to SPSS and do-it-yourself guide to statistics. What is unique about Eelko Huizingh's approach is that this book is based around the needs of undergraduate students embarking on their own research project, and its self-help style is designed to…

Huizingh, Eelko K. R. E.

2007-01-01

423

Statistical Hadronization and Holography

In this paper we consider some issues about the statistical model of the hadronization in a holographic approach. We introduce a Rindler like horizon in the bulk and we understand the string breaking as a tunneling event under this horizon. We calculate the hadron spectrum and we get a thermal, and so statistical, shape for it.

Jacopo Bechi

2009-12-14

424

Finite Order Statistic Experiment

NSDL National Science Digital Library

This resource consists of a Java applet and expository text. The applet is a simulation of the experiment of selecting n objects at random from the first m positive integers. The random variables of interest are the order statistics. The applet illustrates the distributions of the order statistics.

Siegrist, Kyle

425

Weakly sufficient quantum statistics

Some aspects of weak sufficiency of quantum statistics are investigated. In particular, we give necessary and sufficient conditions for the existence of a weakly sufficient statistic for a given family of vector states, investigate the problem of its minimality, and find the relation between weak sufficiency and other notions of sufficiency employed so far.

Katarzyna Lubnauer; Andrzej ?uczak; Hanna Pods?dkowska

2009-11-23

426

Elementary Concepts in Statistics

NSDL National Science Digital Library

This introductory statistics introduction, by StatSoft, gives an overview of variables, classifications, measurements, relations, and other basic statistical concepts. There are also two animated graphs illustrating density and distribution functions, as well as how sample size influences sampling distribution.

2008-12-25

427

Statistical properties of high-resolution overhead images representing different land use categories are analyzed using various local and global statistical image properties based on the shape of the power spectrum, image gradient distributions, edge co-occurrence, and inter-scale wavelet coefficient distributions. The analysis was performed on a database of high-resolution (1 meter) overhead images representing a multitude of different downtown, suburban, commercial, agricultural and wooded exemplars. Various statistical properties relating to these image categories and their relationship are discussed. The categorical variations in power spectrum contour shapes, the unique gradient distribution characteristics of wooded categories, the similarity in edge co-occurrence statistics for overhead and natural images, and the unique edge co-occurrence statistics of downtown categories are presented in this work. Though previous work on natural image statistics has showed some of the unique characteristics for different categories, the relationships for overhead images are not well understood. The statistical properties of natural images were used in previous studies to develop prior image models, to predict and index objects in a scene and to improve computer vision models. The results from our research findings can be used to augment and adapt computer vision algorithms that rely on prior image statistics to process overhead images, calibrate the performance of overhead image analysis algorithms, and derive features for better discrimination of overhead image categories.

Vijayaraj, Veeraraghavan [ORNL; Cheriyadat, Anil M [ORNL; Bhaduri, Budhendra L [ORNL; Vatsavai, Raju [ORNL; Bright, Eddie A [ORNL

2008-01-01

428

The purpose of the Disability Statistics Center is to produce and disseminate statistical information on disability and the status of people with disabilities in American society and to establish and monitor indicators of how conditions are changing over time to meet their health...

429

Confound Those Speculative Statistics

Speculative statistics are model-based statistics. These include deaths attributable to being in a group (deaths linked to a distant cause). Such deaths are those due to primary smoke, second-hand smoke, obesity and radon. This paper reviews the epidemiological model used and introduces a graphical technique to present three big ideas: that a confounder can influence (1) an association in an

Milo Schield

2009-01-01

430

FISHERY STATISTICS UNITED STATES

a review of the fishery statistics for the year 1973 . These statistics include data on the volume of the production of processed fishery products, data on free zings and cold storage holdings, and on foreign trade in fishery commodities. Data on employment of fishermen, fishing craft and gear in the fisheries

431

Explorations in Statistics: Regression

ERIC Educational Resources Information Center

Learning about statistics is a lot like learning about science: the learning is more meaningful if you can actively explore. This seventh installment of "Explorations in Statistics" explores regression, a technique that estimates the nature of the relationship between two things for which we may only surmise a mechanistic or predictive connection.…

Curran-Everett, Douglas

2011-01-01

432

Australian Bureau of Statistics

NSDL National Science Digital Library

For those looking for statistical information on a broad set of themes and geographical areas within Australia, they should visit the Australian Bureau of Statistics Web site. From the main page, visitors can view recent statistical reports, such as the Australian Consumer Price Index, information about the labor force (e.g., employment rates), and a series of occasional papers. Particularly helpful to the casual user will be the Themes section, which provides summary statistics about the environment, tourism, transportation, economic well-being, and education. Additionally, the Bureau publishes reports organized by administrative and regional divisions of the country, a feature that will be helpful to students doing research on a particular area of the country. If users are seeking to learn more about the organization, history, and mission of the Australian Bureau of Statistics, they will find this material located under the About the ABS section of the site.

2000-01-01

433

Statistical laws in linguistics

Zipf's law is just one out of many universal laws proposed to describe statistical regularities in language. Here we review and critically discuss how these laws can be statistically interpreted, fitted, and tested (falsified). The modern availability of large databases of written text allows for tests with an unprecedent statistical accuracy and also a characterization of the fluctuations around the typical behavior. We find that fluctuations are usually much larger than expected based on simplifying statistical assumptions (e.g., independence and lack of correlations between observations).These simplifications appear also in usual statistical tests so that the large fluctuations can be erroneously interpreted as a falsification of the law. Instead, here we argue that linguistic laws are only meaningful (falsifiable) if accompanied by a model for which the fluctuations can be computed (e.g., a generative model of the text). The large fluctuations we report show that the constraints imposed by linguistic laws...

Altmann, Eduardo G

2015-01-01

434

Economic Statistics Briefing Room

NSDL National Science Digital Library

While more than a few curmudgeons have offered their honest opinions about statistics, we here at the Scout Report like to provide our readers with the facts and let them decide on their own. Fortunately, there are sites like the Economic Statistics Briefing Room provided by the White House. Here, visitors can peruse sections that offer information on income, output, transportation, and prices. Drawing on the research and statistical databases of several dozen federal agencies (including the National Agricultural Statistics Services), visitors can view tables and charts that offer such timely material as crude oil prices, poverty rates, and household wealth. Within each section, visitors can view summary statistics, and then if they wish, they can proceed to the homepage of the agency that provided each set of information.

435

Learning Statistics Online: Tools for Teaching Science Methods and Statistics

NSDL National Science Digital Library

The Utah online Virtual Lab is a JAVA program run dynamically off a database. Instructors author a statistical virtual reality simulating theories and data in a specific research focus area by defining independent, predictor, and dependent variables and the relations among them. Students work in an online virtual environment to discover the principles of this simulated reality: they go to a library, read theoretical overviews and scientific puzzles, and then go to a lab, design a study, collect and analyze data, and write a report. A student's design and data analysis decisions are computer-graded and recorded in a database; the written research report can be read by the instructor or by other students in peer groups simulating scientific conventions.

2008-10-27

436

Statistical mechanics of a discrete nonlinear system

Statistical mechanics of the discrete nonlinear Schroedinger equation is studied by means of analytical and numerical techniques. The lower bound of the Hamiltonian permits the construction of standard Gibbsian equilibrium measures for positive temperatures. Beyond the line of T=infinity, we identify a phase transition, through a discontinuity in the partition function. The phase transition is demonstrated to manifest itself in the creation of breather-like localized excitations. Interrelation between the statistical mechanics and the nonlinear dynamics of the system is explored numerically in both regimes.

Rasmussen, K.O.; Cretegny, T.; Kevrekidis, P.G.; Gronbech-Jensen, Niels

1999-09-01

437

Statistical Mechanics of a Discrete Nonlinear System

Statistical mechanics of the discrete nonlinear Schroedinger equation is studied by means of analytical and numerical techniques. The lower bound of the Hamiltonian permits the construction of standard Gibbsian equilibrium measures for positive temperatures. Beyond the line of T={infinity} , we identify a phase transition through a discontinuity in the partition function. The phase transition is demonstrated to manifest itself in the creation of breatherlike localized excitations. Interrelation between the statistical mechanics and the nonlinear dynamics of the system is explored numerically in both regimes. (c) 2000 The American Physical Society.

Rasmussen, K. Oe.; Cretegny, T.; Kevrekidis, P. G.; Groenbech-Jensen, Niels

2000-04-24

438

Applied Math & Statistics: Statistics Minor Curriculum Chart: 2013-2014

Applied Math & Statistics: Statistics Minor Curriculum Chart: 2013-2014 http PSYC 181 CMPE 108 SOCY 103A CMPS 142 TIM 230 Information on the Statistics Minor The statistics minor as preparation for a graduate degree in statistics or biostatistics. Course Information With permission from

Stuart, Josh

439

Statistics 36-756: Advanced Statistics II Syllabus: Fall, 2006

Statistics 36-756: Advanced Statistics II Syllabus: Fall, 2006 Instructor: Stephen E. Fienberg 132G: Â· To consider major topics from statistical theory and the foundations of inference not covered in Statistics 36-756: Advanced Statistics I, such as exchangeability, the axiomatic foundation of subjective probability

Fienberg, Stephen E.

440

Statistics: Part 1 1. Why bother with statistics?

Statistics: Part 1 1. Why bother with statistics? Why is statistics so necessary for observational. But your data just don't seem to back up their claim. Statistics allows you to determine how confidently) practical introduction to those bits of statistics most vital to observational astronomy. 2. What

Francis, Paul

441

NSDL National Science Digital Library

The University of California Los Angeles Statistics Series presents a collection of more than 250 preprints covering a wide array of statistical topics, such as descriptive multivariate analysis, advanced linear models, survey construction and analysis, teaching statistics, and much more. The preprints are arranged by paper number only, hence users must browse the entire list to locate relevant items. Approximately half of the full-text preprints are accessible in HTML, .pdf, or postscript formats. To access preprints not available electronically, users must contact the authors of the papers; author addresses are provided.

442

NSDL National Science Digital Library

This Web site contains a recent report on cancer statistics prepared by the American Cancer Society (ACS) that uses incidence data from the National Cancer Institute and mortality data from the National Center for Health Statistics. The report offers "an up-to-date perspective on the occurrence of cancer" in the United States, including cancer frequency, incidence, mortality, and survival statistics for 2003. The Web site provides links to similar articles, the PubMed citation for the report and other bibliographic resources, and a course based on the article from ACS Online Continuing Medical Education for credit toward the Physician's Recognition Award of the American Medical Association (free registration required).

Ghafoor, Asma.; Jemal, Ahmedin.; Murray, Taylor.; Samuels, Alicia.; Thun, Michael J.; Ward, Elizabeth.

2003-01-01

443

NSDL National Science Digital Library

The FDIC Statistics on Banking is a "quarterly publication that provides aggregate financial and structure information on FDIC-insured institutions, with summary totals by state and charter type." The latest figures for third quarter 1997 are now available.

444

NSDL National Science Digital Library

Database of a series of statistical indicators, primarily economic, but also social and educational, on each OECD countries. Can be viewed either online or downloaded as excel files. The excel downloads also allow for graphical comparisons with other OECD countries.

Development, Organisation F.

445

Computational Statistics Canonical Forest

Computational Statistics Canonical Forest --Manuscript Draft-- Manuscript Number: COST-D-12-00160R3 Full Title: Canonical Forest Article Type: Original Paper Keywords: Canonical linear discriminant analysis; Classification; Ensemble; Linear discriminant analysis; Rotation Forest Corresponding Author

Ahn, Hongshik

446

... statement CDC Emergency Preparedness and Response Maps and Statistics Plague in the United States Plague was first ... West. Plague Worldwide Plague epidemics have occurred in Africa, Asia, and South America but most human cases ...

447

Statistics Netherlands: Key Figures

NSDL National Science Digital Library

This site, provided by the Central Bureau of Statistics in the Netherlands, offers current data on key social and economic indicators. These include population, labor, industry, prices, energy, health and welfare, and the environment.

1998-01-01

448

NSDL National Science Digital Library

Before entering the main portion of this interactive introduction to statistics, visitors will have to answer a few quick questions on polls. It's actually a bit fun, and it serves as a nice introduction to the site. Once visitors are in the main site, they will get the opportunity to learn about statistics through the lens of a mock election. The site contains areas such as "How Random is Random?", "Being Confident", and "What Can Go Wrong". Along with concise explanations of each element of statistics, visitors can also take part in an interactive quiz and some additional polling activities. The site also includes a number of external links for visitors who wish to explore additional topics within the field of statistics.

449

Mathematics and Statistics Models

NSDL National Science Digital Library

Developed by Bob MacKay, Clark College. What are Mathematical and Statistical Models These types of models are obviously related, but there are also real differences between them. Mathematical Models: grow out of ...

450

Playing at Statistical Mechanics

ERIC Educational Resources Information Center

Discussed are the applications of counting techniques of a sorting game to distributions and concepts in statistical mechanics. Included are the following distributions: Fermi-Dirac, Bose-Einstein, and most probable. (RH)

Clark, Paul M.; And Others

1974-01-01

451

NSDL National Science Digital Library

This resource consists of a Java applet and expository text. The applet simulates the order statistics of a random sample from a given distribution. The sample size, order, and sampling distribution can be specified.

Siegrist, Kyle

452

Statistics is an important tool in pharmacological research that is used to summarize (descriptive statistics) experimental data in terms of central tendency (mean or median) and variance (standard deviation, standard error of the mean, confidence interval or range) but more importantly it enables us to conduct hypothesis testing. This is of particular importance when attempting to determine whether the pharmacological effect of one drug is superior to another which clearly has implications for drug development and getting that next paper published in a respectable journal! Therefore, it is essential for pharmacologists to have an understanding of the uses and abuses of statistics. With this in mind, the British Journal of Pharmacology has commissioned a number of review articles to highlight the uses of statistics in experimental design and analysis. PMID:17618311

Spina, D

2007-10-01

453

Understanding Solar Flare Statistics

NASA Astrophysics Data System (ADS)

A review is presented of work aimed at understanding solar flare statistics, with emphasis on the well known flare power-law size distribution. Although avalanche models are perhaps the favoured model to describe flare statistics, their physical basis is unclear, and they are divorced from developing ideas in large-scale reconnection theory. An alternative model, aimed at reconciling large-scale reconnection models with solar flare statistics, is revisited. The solar flare waiting-time distribution has also attracted recent attention. Observed waiting-time distributions are described, together with what they might tell us about the flare phenomenon. Finally, a practical application of flare statistics to flare prediction is described in detail, including the results of a year of automated (web-based) predictions from the method.

Wheatland, M. S.

2005-12-01

454

Statistical Associates Publishing

NSDL National Science Digital Library

Statistical Associates Publishing is a creation of Professor Dave Garson and hosts a number of free statistics e-books, and some low-cost Kindle versions as well. Use of the site is password-protected, so visit the Register link first, then continue to download e-books (in PDF form) on topics such as Creating Simulated Datasets, Narrative Analysis, Cluster Analysis, Ordinal Regression, Survey Research, Structural Equation Modeling, and much more.

Garson, G. D.

2009-01-29

455

NSDL National Science Digital Library

This page, created by the Department of Statistics at the University of California, Los Angeles, has data sets used by statistics classes. The html files in the second column contain descriptions of a particular data set and a link to the data at the end of the file. There are also .dat and .dta files that contain just data, with no description. The site is simple, but still contains a great deal of useful data.

2009-01-30

456

NSDL National Science Digital Library

This course, created by Wen Xiao-Geng of the Massachusetts Institute of Technology, is the second in the series of undergraduate Statistical Physics courses and features comprehensive lecture notes and assignments. Course topics include: probability distributions for both classical and quantum systems. Additional topics include: microcanonical, canonical, grand canonical partition-functions, associated thermodynamic potentials, homogeneous and heterogeneous systems. This would be a valuable resource for either an instructor or student in a statistics class.

Wen, Xiao-Gang

457

NSDL National Science Digital Library

This collection of datasets from the University of Massachusetts at Amherst is categorized by topic. Each dataset and its description are in text format. Topics include: analysis of variance, analysis of covariance, cluster analysis, contingency table analysis, correlation analysis, descriptive statistics, discriminant analysis, factor analysis, nonparametric analysis, multiple regression, nonlinear regression, logistic regression, survival analysis, and time series analysis. This is a large collection of data and software which can be implemented into different aspects of statistical study.

2009-01-23

458

United Nations Global Statistics

NSDL National Science Digital Library

This UN directory site allows users to quickly access national statistics through the official outlets of UN-member states and international statistics through dozens of UN programs and agencies as well as autonomous organizations such as the World Trade Organization and Eurostat. Data covered include, but are not limited to, health care, economics, politics, environment, and social demographics. The site offers a simple search engine with Boolean capabilities and is updated on a biweekly basis.

Division., United N.

459

Stellar Evolution A Statistical Model

Stellar Evolution A Statistical Model Statistical Computation Analysis of the Hyades Cluster Embedding Computer Models for Stellar Evolution into a Coherent Statistical Analysis David A. van Dyk1 Analysis of Stellar Evolution #12;Stellar Evolution A Statistical Model Statistical Computation Analysis

van Dyk, David

460

FISHERY STATISTICS E UNITED STATES

SH 11 .A443X FISH FISHERY STATISTICS E UNITED STATES ^ 1951 &ch 3. \\Â§^ ^/'Â· m:^ STATISTICAL DIGEST. Farley, Director Statistical Digest 30 FISHERY STATISTICS OF THE UNITED STATES 1951 BY A. W. ANDERSON;Fishery Statistics of the United States and Alaska are compiled and published annually to make available

461

Environmental statistics and optimal regulation.

Any organism is embedded in an environment that changes over time. The timescale for and statistics of environmental change, the precision with which the organism can detect its environment, and the costs and benefits of particular protein expression levels all will affect the suitability of different strategies--such as constitutive expression or graded response--for regulating protein levels in response to environmental inputs. We propose a general framework-here specifically applied to the enzymatic regulation of metabolism in response to changing concentrations of a basic nutrient-to predict the optimal regulatory strategy given the statistics of fluctuations in the environment and measurement apparatus, respectively, and the costs associated with enzyme production. We use this framework to address three fundamental questions: (i) when a cell should prefer thresholding to a graded response; (ii) when there is a fitness advantage to implementing a Bayesian decision rule; and (iii) when retaining memory of the past provides a selective advantage. We specifically find that: (i) relative convexity of enzyme expression cost and benefit influences the fitness of thresholding or graded responses; (ii) intermediate levels of measurement uncertainty call for a sophisticated Bayesian decision rule; and (iii) in dynamic contexts, intermediate levels of uncertainty call for retaining memory of the past. Statistical properties of the environment, such as variability and correlation times, set optimal biochemical parameters, such as thresholds and decay rates in signaling pathways. Our framework provides a theoretical basis for interpreting molecular signal processing algorithms and a classification scheme that organizes known regulatory strategies and may help conceptualize heretofore unknown ones. PMID:25254493

Sivak, David A; Thomson, Matt

2014-09-01

462

Statistical Mechanics of Metallic Glasses and Liquids

It is difficult to formulate the statistical mechanical theory of liquids and glasses, because phonons, which are the basis for the statistical mechanics of lattice dynamics in crystals, are strongly scattered and have a very short lifetime in liquids and glasses. Instead computer simulation and the free-volume theory are most frequently used in explaining experimental results on metallic glasses. However, both of them suffer from serious problems as discussed in this paper. We propose an alternative approach based upon the dynamics of the atomic level stresses. We review recent progress with this approach, and show that it is possible to calculate thermodynamic quantities, including the glass transition temperature and the kinetics of structural relaxation by this approach.

Egami, Takeshi [ORNL; Levashov, Valentin A [ORNL; Morris, James R [ORNL; Haruyama, O. [Tokyo University of Science, Japan

2010-01-01

463

Counting statistics for mesoscopic conductors with internal degrees of freedom

We consider the transport of electrons passing through a mesoscopic device possessing internal dynamical quantum degrees of freedom. The mutual interaction between the system and the conduction electrons contributes to the current fluctuations, which we describe in terms of full counting statistics. We identify conditions where this discriminates coherent from incoherent internal dynamics, and also identify and illustrate conditions under which the device acts to dynamically bunch transmitted or reflected electrons, thereby generating super-Poissonian noise.

Christopher Birchall; Henning Schomerus

2010-04-29

464

Counting statistics for mesoscopic conductors with internal degrees of freedom

We consider the transport of electrons passing through a mesoscopic device possessing internal dynamical quantum degrees of freedom. The mutual interaction between the system and the conduction electrons contributes to the current fluctuations, which we describe in terms of full counting statistics. We identify conditions where this discriminates coherent from incoherent internal dynamics, and also identify and illustrate conditions under which the device acts to dynamically bunch transmitted or reflected electrons, thereby generating super-Poissonian noise.

Birchall, Christopher

2010-01-01

465

Statistical transmutation in doped quantum dimer models.

We prove a "statistical transmutation" symmetry of doped quantum dimer models on the square, triangular, and kagome lattices: the energy spectrum is invariant under a simultaneous change of statistics (i.e., bosonic into fermionic or vice versa) of the holes and of the signs of all the dimer resonance loops. This exact transformation enables us to define the duality equivalence between doped quantum dimer Hamiltonians and provides the analytic framework to analyze dynamical statistical transmutations. We investigate numerically the doping of the triangular quantum dimer model with special focus on the topological Z(2) dimer liquid. Doping leads to four (instead of two for the square lattice) inequivalent families of Hamiltonians. Competition between phase separation, superfluidity, supersolidity, and fermionic phases is investigated in the four families. PMID:23031119

Lamas, C A; Ralko, A; Cabra, D C; Poilblanc, D; Pujol, P

2012-07-01

466

Statistical Training for Social Workers.

ERIC Educational Resources Information Center

The value of statistical training for social workers is addressed, along with current levels of training and general educational principles for statistical training. Bachelor's, master's, and doctoral statistical curricula are proposed. (Author/MH)

Glisson, Charles; Fischer, Joel

1987-01-01

467

Statistical mechanics of fullerene coalescence growth

Among the different carbon allotropes fullerenes are exceptionally intriguing for their spheroidal topology out of pentagons and hexagons. However, the dominant formation mode is still ambiguous. Here, we analyze the fullerene formation process by the statistical analysis of fullerene sizes produced in a laser-induced microplasma finding that a simple two-parameter lognormal distribution describes impressively well the cluster frequencies under various conditions. Our findings clearly reveal coalescent growth following a classical collision dynamics and disagree with several earlier assumptions.

Maul, Jochen; Berg, Thomas; Schoenhense, Gerd; Huber, Gerhard [Institut fuer Physik, Johannes Gutenberg-Universitaet, Staudingerweg 7, D-55099 Mainz (Germany); Marosits, Edit [Max Planck-Institut fuer Chemie, Becherweg 27, D-55128 Mainz (Germany)

2006-10-15

468

Simulating Fibre Suspensions: Lagrangian versus Statistical Approach

NASA Astrophysics Data System (ADS)

Fibre suspensions exhibit complex dynamical flow phenomena and are at the same time of immense practical importance, notably in the pulp and paper industries. NTNU and TU Delft have in a collaborative research project adopted two alternative strategies in the simulation of dilute fibre suspensions, namely a statistical approach [2] and a Lagrangian particle treatment [4]. The two approaches have their own advantages and disadvantages. In this paper we aim for the first time to compare the performance of the two.

Zhao, L. H.; Andersson, H. I.; Gillissen, J. J. J.; Boersma, B. J.

469

Testing quantum mechanics: a statistical approach

NASA Astrophysics Data System (ADS)

As experiments continue to push the quantum-classical boundary using increasingly complex dynamical systems, the interpretation of experimental data becomes more and more challenging: when the observations are noisy, indirect, and limited, how can we be sure that we are observing quantum behavior? This tutorial highlights some of the difficulties in such experimental tests of quantum mechanics, using optomechanics as the central example, and discusses how the issues can be resolved using techniques from statistics and insights from quantum information theory.

Tsang, Mankei

2013-12-01

470

Statistical Physics of Fracture

Disorder and long-range interactions are two of the key components that make material failure an interesting playfield for the application of statistical mechanics. The cornerstone in this respect has been lattice models of the fracture in which a network of elastic beams, bonds, or electrical fuses with random failure thresholds are subject to an increasing external load. These models describe on a qualitative level the failure processes of real, brittle, or quasi-brittle materials. This has been particularly important in solving the classical engineering problems of material strength: the size dependence of maximum stress and its sample-to-sample statistical fluctuations. At the same time, lattice models pose many new fundamental questions in statistical physics, such as the relation between fracture and phase transitions. Experimental results point out to the existence of an intriguing crackling noise in the acoustic emission and of self-affine fractals in the crack surface morphology. Recent advances in computer power have enabled considerable progress in the understanding of such models. Among these partly still controversial issues, are the scaling and size-effects in material strength and accumulated damage, the statistics of avalanches or bursts of microfailures, and the morphology of the crack surface. Here we present an overview of the results obtained with lattice models for fracture, highlighting the relations with statistical physics theories and more conventional fracture mechanics approaches.

Alava, Mikko [Helsinki University of Technology, Helsinki, Finland; Nukala, Phani K [ORNL; Zapperi, Stefano [University of La Sapienza, Rome

2006-05-01

471

Spatial statistics of marine boundary layer clouds Gregory M. Lewis1

and Atmospheric Dynamics: Boundary layer processes; 3359 Meteorology and Atmospheric Dynamics: Radiative processesSpatial statistics of marine boundary layer clouds Gregory M. Lewis1 The Fields Institute, Toronto. Szczodrak (2004), Spatial statistics of marine boundary layer clouds, J. Geophys. Res., 109, D04104, doi:10

Lewis, Greg

472

National Transportation Statistics 2001

NSDL National Science Digital Library

Released in July 2002, this 431-page document prepared by the United States Bureau of Transportation Statistics contains almost every piece of aggregate data on transportation imaginable. While going through the entire document may be a challenge, the report is divided into more readily digestible sections such as Transportation System, Transportation Safety, and Transportation and the Economy. The majority of the report consists of tables and charts that summarize a variety of transportation statistics, such as Retail New Passenger Car Sales, Principal Means of Transportation to Work, and Railroad Passenger Safety Data. This exhaustive survey of the United States transportation system will be most helpful to those doing research in the field of transportation policy or those just looking for useful statistics.

2002-01-01

473

UNESCO Institute for Statistics

NSDL National Science Digital Library

Established in 1999, the UNESCO Institute for Statistics (UIS) was designed to meet both the needs of UNESCO Member States and to provide the international community with a wide range of statistical information in order to "analyze the efficiency and effectiveness of their programmes and to inform their policy decisions." The UIC is hosted by the University of Montreal, and performs work around four primary themes, including education, literacy, culture & communication, and science & technology. Overall, the site is a remarkable source of information, including databases, working papers, country profiles, statistical tables, and methodological material about the conduct of their research. Several of these works are featured prominently on their homepage including a working paper on financing the expansion of educational opportunity in Latin America and the Caribbean and an electronic questionnaire on science and technology.

474

Statistical Understanding Made Simple

NSDL National Science Digital Library

Teaching statistics can be tough for even experienced instructors, so it is nice to learn about the Statistical Understanding Made Simple (SUMS) website. Created by researchers at the University of Glasgow, the site helps users build "interactive, fun and highly effective tutorials designed to help students understand basic statistics." Visitors who wish to have the resource generator create tutorials will need to register on the site and provide a small data set. Of course, visitors can also check out the "Ready Made Tutorials" area, where they will discover projects that examine the relationship between height and weight and the effect of cognitive behavioral therapy on depression. Additionally, the site also contains several games which students can use to explore the effects of standard deviation and histograms.

475

Statistical Mechanics of Wormholes

The statistical mechanics of a gas of Einstein-Kalb-Ramond wormholes is studied in this paper. The wormholes studied are the result of sewing together two Reissner-Nordstrom-type black hole metrics at their horizons. By requiring the stress-energy tensor associated with this geometry to be that of a Kalb-Ramond field, we obtain the mass and Kalb-Ramond `charge` of the wormholes in terms of the parameters describing the mass density, tension and pressure. We investigate the statistical mechanics of this system of wormholes within the context of the statistical bootstrap model. A gas of such wormholes is found to obey the bootstrap condition only for an extreme, non-thermodynamic, energy and `charge` distribution among the particles. We comment briefly on the scattering of quantum wormholes.

Paul H. Cox; Benjamin C. Harms; Shaoqi Hou

2011-09-29

476

NASA Astrophysics Data System (ADS)

Energy level statistics following the Gaussian Symplectic Ensemble (GSE) of Random Matrix Theory have been predicted theoretically and observed numerically in numerous quantum chaotic systems. However, in all these systems there has been one unifying feature: the combination of half-integer spin and time-reversal invariance. Here we provide an alternative mechanism for obtaining GSE statistics that is derived from geometric symmetries of a quantum system which alleviates the need for spin. As an example, we construct a quantum graph with a discrete symmetry given by the quaternion group Q8 and observe GSE statistics within one of its subspectra. We then show how to isolate this subspectrum and construct a quantum graph with a scalar valued wave function and a pure GSE spectrum.

Joyner, Christopher H.; Müller, Sebastian; Sieber, Martin

2014-09-01

477

The International Year of Statistics

NSDL National Science Digital Library

Statistics is a subject for all seasons and years, but 2013 is the International Year of Statistics, a designation supported by almost 1,850 organizations. The primary movers behind this noble activity include the American Statistical Association, the International Biometric Society, and the Royal Statistical Society. The goal of this initiative is to promote "the importance of statistics to the scientific community, business and government data users, the media," and a range of other users. On the website, visitors can make their way through four main sections, including What is Statistics?, Statistics as a Career, Teacher Resources, and Statistics 2013 Posters. The Teacher Resources area is a real pip, as it features teacher resources for over tw