WorldWideScience

Sample records for finite universe hypotheses

  1. Olber's Paradox Revisited in a Static and Finite Universe

    Science.gov (United States)

    Couture, Gilles

    2012-01-01

    Building a Universe populated by stars identical to our Sun and taking into consideration the wave-particle duality of light, the biological limits of the human eye, the finite size of stars and the finiteness of our Universe, we conclude that the sky could very well be dark at night. Besides the human eye, the dominant parameter is the finite…

  2. The Finite and Moving Order Multinomial Universal Portfolio

    International Nuclear Information System (INIS)

    Tan, Choon Peng; Pang, Sook Theng

    2013-01-01

    An upper bound for the ratio of wealths of the best constant -rebalanced portfolio to that of the multinomial universal portfolio is derived. The finite- order multinomial universal portfolios can reduce the implementation time and computer-memory requirements for computation. The improved performance of the finite-order portfolios on some selected local stock-price data sets is observed.

  3. ITSSOIN Hypotheses

    NARCIS (Netherlands)

    Anheier, H.K.; Krlev, G.; Preuss, S.; Mildenberger, G.; Bekkers, R.H.F.P.; Brink Lund, A.

    2014-01-01

    This report brings together findings from the first ITSSOIN project working steps to formulate empirically testable hypotheses on the impact of the third sector and social innovation – in particular regarding the role of the third sector in generating social innovation but also with reference to

  4. Learning to Question: The Roles of Multiple Hypotheses, Successive Approximations, Balloons and Toilet Paper in University Science Programs of Southwestern Amazonia

    Science.gov (United States)

    Brown, I. Foster

    2008-01-01

    Learning to question is essential for determining pathways of conservation and development in southwestern Amazonia during a time of rapid global environmental change. Teaching such an approach in graduate science programs in regional universities can be done using play-acting and simulation exercises. Multiple working hypotheses help students…

  5. How the universe got its spots diary of a finite time in a finite space

    CERN Document Server

    Levin, Janna

    2002-01-01

    Is the universe infinite, or is it just really big? Does nature abhor infinity? In startling and beautiful prose, Janna Levin's diary of unsent letters to her mother describes what we know about the shape and extent of the universe, about its beginning and its end. She grants the uninitiated access to the astounding findings of contemporary theoretical physics and makes tangible the contours of space and time--those very real curves along which apples fall and planets orbit. Levin guides the reader through the observations and thought-experiments that have enabled physicists to begin charting the universe. She introduces the cosmic archaeology that makes sense of the pattern of hot spots left over from the big bang, a pursuit on the verge of discovering the shape of space itself. And she explains the topology and the geometry of the universe now coming into focus--a strange map of space full of black holes, chaotic flows, time warps, and invisible strings. Levin advances the controversial idea that this map ...

  6. An Introduction of Finite Element Method in the Engineering Teaching at the University of Camaguey.

    Science.gov (United States)

    Napoles, Elsa; Blanco, Ramon; Jimenez, Rafael; Mc.Pherson, Yoanka

    This paper illuminates experiences related to introducing finite element methods (FEM) in mechanical and civil engineering courses at the University of Camaguey in Cuba and provides discussion on using FEM in postgraduate courses for industry engineers. Background information on the introduction of FEM in engineering teaching is focused on…

  7. Chiral random matrix model at finite chemical potential: Characteristic determinant and edge universality

    Directory of Open Access Journals (Sweden)

    Yizhuang Liu

    2016-08-01

    Full Text Available We derive an exact formula for the stochastic evolution of the characteristic determinant of a class of deformed Wishart matrices following from a chiral random matrix model of QCD at finite chemical potential. In the WKB approximation, the characteristic determinant describes a sharp droplet of eigenvalues that deforms and expands at large stochastic times. Beyond the WKB limit, the edges of the droplet are fuzzy and described by universal edge functions. At the chiral point, the characteristic determinant in the microscopic limit is universal. Remarkably, the physical chiral condensate at finite chemical potential may be extracted from current and quenched lattice Dirac spectra using the universal edge scaling laws, without having to solve the QCD sign problem.

  8. Finite

    Directory of Open Access Journals (Sweden)

    W.R. Azzam

    2015-08-01

    Full Text Available This paper reports the application of using a skirted foundation system to study the behavior of foundations with structural skirts adjacent to a sand slope and subjected to earthquake loading. The effect of the adopted skirts to safeguard foundation and slope from collapse is studied. The skirts effect on controlling horizontal soil movement and decreasing pore water pressure beneath foundations and beside the slopes during earthquake is investigated. This technique is investigated numerically using finite element analysis. A four story reinforced concrete building that rests on a raft foundation is idealized as a two-dimensional model with and without skirts. A two dimensional plain strain program PLAXIS, (dynamic version is adopted. A series of models for the problem under investigation were run under different skirt depths and lactation from the slope crest. The effect of subgrade relative density and skirts thickness is also discussed. Nodal displacement and element strains were analyzed for the foundation with and without skirts and at different studied parameters. The research results showed a great effectiveness in increasing the overall stability of the slope and foundation. The confined soil footing system by such skirts reduced the foundation acceleration therefore it can be tended to damping element and relieved the transmitted disturbance to the adjacent slope. This technique can be considered as a good method to control the slope deformation and decrease the slope acceleration during earthquakes.

  9. Precise determination of universal finite volume observables in the Gross-Neveu model

    International Nuclear Information System (INIS)

    Korzec, T.

    2007-01-01

    The Gross-Neveu model is a quantum field theory in two space time dimensions that shares many features with quantum chromo dynamics. In this thesis the continuum model and its discretized versions are reviewed and a finite volume renormalization scheme is introduced and tested. Calculations in the limit of infinitely many fermion flavors as well as perturbative computations are carried out. In extensive Monte-Carlo simulations of the one flavor and the four flavor lattice models with Wilson fermions a set of universal finite volume observables is calculated to a high precision. In the one flavor model which is equivalent to the massless Thirring model the continuum extrapolated Monte-Carlo results are confronted with an exact solution of the model. (orig.)

  10. Testing statistical hypotheses

    CERN Document Server

    Lehmann, E L

    2005-01-01

    The third edition of Testing Statistical Hypotheses updates and expands upon the classic graduate text, emphasizing optimality theory for hypothesis testing and confidence sets. The principal additions include a rigorous treatment of large sample optimality, together with the requisite tools. In addition, an introduction to the theory of resampling methods such as the bootstrap is developed. The sections on multiple testing and goodness of fit testing are expanded. The text is suitable for Ph.D. students in statistics and includes over 300 new problems out of a total of more than 760. E.L. Lehmann is Professor of Statistics Emeritus at the University of California, Berkeley. He is a member of the National Academy of Sciences and the American Academy of Arts and Sciences, and the recipient of honorary degrees from the University of Leiden, The Netherlands and the University of Chicago. He is the author of Elements of Large-Sample Theory and (with George Casella) he is also the author of Theory of Point Estimat...

  11. Is our Universe finite? New physics by dark matter. On hike through black, white, and worm holes

    Energy Technology Data Exchange (ETDEWEB)

    Birkholz, Claus

    2014-07-01

    Quantum Gravity (QG) allows finite-dimensional representations for its particles without getting into the traditional trouble with probability conservation. As in QG a particle and a universe are described by identical equations, our universe is expected to be finite, as well. Within a finite universe, not only space-time is limited, but there also must exist upper bounds for energy-momentum: A particle cannot be accelerated up to arbitrary energy. By erasing major inconsistencies in quantum field theories, their current types are proved to systematically destroying structure of our universe, which, thus, must be much greater than officially assumed. The key is traced back to Dark Matter. Black Holes are argued to be ''particle vertices'' with respect to our universe, while ''White Holes'', here, are not yet identified. The intermediary exchange state between such a related pair, by GR is represented as a ''Worm Hole''. For more information on QG and GUT see www.q-grav.com.

  12. Monadic structures over an ordered universal random graph and finite automata

    Science.gov (United States)

    Dudakov, Sergey M.

    2011-10-01

    We continue the investigation of the expressive power of the language of predicate logic for finite algebraic systems embedded in infinite systems. This investigation stems from papers of M. A. Taitslin, M. Benedikt and L. Libkin, among others. We study the properties of a finite monadic system which can be expressed by formulae if such a system is embedded in a random graph that is totally ordered in an arbitrary way. The Büchi representation is used to connect monadic structures and formal languages. It is shown that, if one restricts attention to formulae that are -invariant in totally ordered random graphs, then these formulae correspond to finite automata. We show that =-invariant formulae expressing the properties of the embedded system itself can express only Boolean combinations of properties of the form `the cardinality of an intersection of one-place predicates belongs to one of finitely many fixed finite or infinite arithmetic progressions'.

  13. Exact solutions, finite time singularities and non-singular universe models from a variety of Λ(t) cosmologies

    Science.gov (United States)

    Pan, Supriya

    2018-01-01

    Cosmological models with time-dependent Λ (read as Λ(t)) have been investigated widely in the literature. Models that solve background dynamics analytically are of special interest. Additionally, the allowance of past or future singularities at finite cosmic time in a specific model signals for a generic test on its viabilities with the current observations. Following these, in this work we consider a variety of Λ(t) models focusing on their evolutions and singular behavior. We found that a series of models in this class can be exactly solved when the background universe is described by a spatially flat Friedmann-Lemaître-Robertson-Walker (FLRW) line element. The solutions in terms of the scale factor of the FLRW universe offer different universe models, such as power-law expansion, oscillating, and the singularity free universe. However, we also noticed that a large number of the models in this series permit past or future cosmological singularities at finite cosmic time. At last we close the work with a note that the avoidance of future singularities is possible for certain models under some specific restrictions.

  14. Retroduction, Multiverse Hypotheses and Their Testability

    OpenAIRE

    Stoeger, William R.

    2006-01-01

    The actual existence of collections of universes -- multiverses -- is strongly suggested by leading approaches to quantum cosmology, and has been proposed earlier as an attractive way to explain the apparent fine-tuned character of our universe. But, how can such hypotheses be tested? After briefly discussing the key distinction between possible and really existing multiverses, and the importance of an adequate generating process, we focus on elaborating how multiverse hypotheses can be retro...

  15. Universality of the emergent scaling in finite random binary percolation networks.

    Science.gov (United States)

    Zhai, Chongpu; Hanaor, Dorian; Gan, Yixiang

    2017-01-01

    In this paper we apply lattice models of finite binary percolation networks to examine the effects of network configuration on macroscopic network responses. We consider both square and rectangular lattice structures in which bonds between nodes are randomly assigned to be either resistors or capacitors. Results show that for given network geometries, the overall normalised frequency-dependent electrical conductivities for different capacitor proportions are found to converge at a characteristic frequency. Networks with sufficiently large size tend to share the same convergence point uninfluenced by the boundary and electrode conditions, can be then regarded as homogeneous media. For these networks, the span of the emergent scaling region is found to be primarily determined by the smaller network dimension (width or length). This study identifies the applicability of power-law scaling in random two phase systems of different topological configurations. This understanding has implications in the design and testing of disordered systems in diverse applications.

  16. Finite element analysis in fluids; Proceedings of the Seventh International Conference on Finite Element Methods in Flow Problems, University of Alabama, Huntsville, Apr. 3-7, 1989

    International Nuclear Information System (INIS)

    Chung, T.J.; Karr, G.R.

    1989-01-01

    Recent advances in computational fluid dynamics are examined in reviews and reports, with an emphasis on finite-element methods. Sections are devoted to adaptive meshes, atmospheric dynamics, combustion, compressible flows, control-volume finite elements, crystal growth, domain decomposition, EM-field problems, FDM/FEM, and fluid-structure interactions. Consideration is given to free-boundary problems with heat transfer, free surface flow, geophysical flow problems, heat and mass transfer, high-speed flow, incompressible flow, inverse design methods, MHD problems, the mathematics of finite elements, and mesh generation. Also discussed are mixed finite elements, multigrid methods, non-Newtonian fluids, numerical dissipation, parallel vector processing, reservoir simulation, seepage, shallow-water problems, spectral methods, supercomputer architectures, three-dimensional problems, and turbulent flows

  17. Everything coming out of nothing vs. a finite, open and contingent universe

    CERN Document Server

    Gonzalo, Julio A

    2012-01-01

    Very often, contemporary theoretical cosmologists ignore the crucial contributions made in Medieval Europe to the birth of modern physics. This book intends to bridge the gap in accessible language for the non specialist. This book puts in a proper historical perspective, that the universe is intelligible as attested by the monumental fact of modern science, and, therefore, that it is contingent, and therefore created.

  18. Kardar-Parisi-Zhang universality class in (2+1) dimensions: universal geometry-dependent distributions and finite-time corrections.

    Science.gov (United States)

    Oliveira, T J; Alves, S G; Ferreira, S C

    2013-04-01

    The dynamical regimes of models belonging to the Kardar-Parisi-Zhang (KPZ) universality class are investigated in d=2+1 by extensive simulations considering flat and curved geometries. Geometry-dependent universal distributions, different from their Tracy-Widom counterpart in one dimension, were found. Distributions exhibit finite-time corrections hallmarked by a shift in the mean decaying as t(-β), where β is the growth exponent. Our results support a generalization of the ansatz h=v(∞)t+(Γt)(β)χ+η+ζt(-β) to higher dimensions, where v(∞), Γ, ζ, and η are nonuniversal quantities whereas β and χ are universal and the last one depends on the surface geometry. Generalized Gumbel distributions provide very good fits of the distributions in at least four orders of magnitude around the peak, which can be used for comparisons with experiments. Our numerical results call for analytical approaches and experimental realizations of the KPZ class in two-dimensional systems.

  19. Topics in quantum groups and finite-type invariants mathematics at the independent University of Moscow

    CERN Document Server

    Arkhipov, S M; Odesskii, A V; Feigin, B; Vassiliev, V

    1998-01-01

    This volume presents the first collection of articles consisting entirely of work by faculty and students of the Higher Mathematics College of the Independent University of Moscow (IUM). This unique institution was established to train elite students to become research scientists. Covered in the book are two main topics: quantum groups and low-dimensional topology. The articles were written by participants of the Feigin and Vassiliev seminars, two of the most active seminars at the IUM.

  20. Higher correlations, universal distributions, and finite size scaling in the field theory of depinning.

    Science.gov (United States)

    Le Doussal, Pierre; Wiese, Kay Jörg

    2003-10-01

    Recently we constructed a renormalizable field theory up to two loops for the quasistatic depinning of elastic manifolds in a disordered environment. Here we explore further properties of the theory. We show how higher correlation functions of the displacement field can be computed. Drastic simplifications occur, unveiling much simpler diagrammatic rules than anticipated. This is applied to the universal scaled width distribution. The expansion in d=4-epsilon predicts that the scaled distribution coincides to the lowest orders with the one for a Gaussian theory with propagator G(q)=1/q(d+2 zeta), zeta being the roughness exponent. The deviations from this Gaussian result are small and involve higher correlation functions, which are computed here for different boundary conditions. Other universal quantities are defined and evaluated: We perform a general analysis of the stability of the fixed point. We find that the correction-to-scaling exponent is omega=-epsilon and not -epsilon/3 as used in the analysis of some simulations. A more detailed study of the upper critical dimension is given, where the roughness of interfaces grows as a power of a logarithm instead of a pure power.

  1. On the extreme value statistics of normal random matrices and 2D Coulomb gases: Universality and finite N corrections

    Science.gov (United States)

    Ebrahimi, R.; Zohren, S.

    2018-03-01

    In this paper we extend the orthogonal polynomials approach for extreme value calculations of Hermitian random matrices, developed by Nadal and Majumdar (J. Stat. Mech. P04001 arXiv:1102.0738), to normal random matrices and 2D Coulomb gases in general. Firstly, we show that this approach provides an alternative derivation of results in the literature. More precisely, we show convergence of the rescaled eigenvalue with largest modulus of a normal Gaussian ensemble to a Gumbel distribution, as well as universality for an arbitrary radially symmetric potential. Secondly, it is shown that this approach can be generalised to obtain convergence of the eigenvalue with smallest modulus and its universality for ring distributions. Most interestingly, the here presented techniques are used to compute all slowly varying finite N correction of the above distributions, which is important for practical applications, given the slow convergence. Another interesting aspect of this work is the fact that we can use standard techniques from Hermitian random matrices to obtain the extreme value statistics of non-Hermitian random matrices resembling the large N expansion used in context of the double scaling limit of Hermitian matrix models in string theory.

  2. Scientific 'Laws', 'Hypotheses' and 'Theories'

    Indian Academy of Sciences (India)

    No.10,1998. J R Lakshmana Rao. Some commonly held erroneous notions about the terms laws, hypotheses and theories are pointed out with specific examples from different branches of science. Hypotheses ... John Stuart Mill, who is spoken of as the father of induction and who, in the ..... True Science is a wild adventure.

  3. [Puzzles and hypotheses of acupuncture].

    Science.gov (United States)

    Li, Yong-ming

    2013-11-01

    Some results of clinical trials from the West on traditional acupuncture with modern research design have puzzled the acupuncture community. These include (1) what is the implication of acupuncture, (2) whether acupuncture point has its specificity, and 3) why practical experience in the East is quite different from research observations in the West. Three hypotheses, namely, Acupuncture Healing Effect, Pan-acupoint Phenomenon, and Hard Acupuncture and Soft Acupuncture, are proposed here to explain these sensitive issues. Further investigation with scientific approach may prove or reject these hypotheses. The resolving of these issues will shed light on the re-evaluation of traditional acupuncture and promote the maturation of modern acupuncture theory.

  4. Scientific 'Laws', 'Hypotheses' and 'Theories'

    Indian Academy of Sciences (India)

    Science endeavours to give a meaningful description of the world of phenomena using what are known as laws, hypotheses and theories. Logicians and students of scientific method analyse the structure of scientific knowledge and try to determine the precise significance of these terms. But it is surprising to note.

  5. Amerind taxonomy and testable hypotheses.

    Science.gov (United States)

    Pichardo, M

    1998-06-01

    The acceptance of a 30,000 yr B.P. age for Valsequillo sets new parameters for hypotheses of Paleoindian entry into America. A review of Amerind taxonomy defines the early groups as Otamid-Sundadonts. Isolation in America led to an adaptive radiation that has implications for the origin and dispersal of Pithecanthropus.

  6. On error probability exponents of many hypotheses optimal testing ...

    African Journals Online (AJOL)

    In this paper we study a model of hypotheses testing consisting of with to simple homogeneous stationary Markov chains ith finite number of states such that having different distributions from four possible transmission probabilities.For solving this problem we apply the method of type and large deviation techniques (LTD).

  7. Testing statistical hypotheses of equivalence

    CERN Document Server

    Wellek, Stefan

    2010-01-01

    Equivalence testing has grown significantly in importance over the last two decades, especially as its relevance to a variety of applications has become understood. Yet published work on the general methodology remains scattered in specialists' journals, and for the most part, it focuses on the relatively narrow topic of bioequivalence assessment.With a far broader perspective, Testing Statistical Hypotheses of Equivalence provides the first comprehensive treatment of statistical equivalence testing. The author addresses a spectrum of specific, two-sided equivalence testing problems, from the

  8. Universal Signatures of Quantum Critical Points from Finite-Size Torus Spectra: A Window into the Operator Content of Higher-Dimensional Conformal Field Theories.

    Science.gov (United States)

    Schuler, Michael; Whitsitt, Seth; Henry, Louis-Paul; Sachdev, Subir; Läuchli, Andreas M

    2016-11-18

    The low-energy spectra of many body systems on a torus, of finite size L, are well understood in magnetically ordered and gapped topological phases. However, the spectra at quantum critical points separating such phases are largely unexplored for (2+1)D systems. Using a combination of analytical and numerical techniques, we accurately calculate and analyze the low-energy torus spectrum at an Ising critical point which provides a universal fingerprint of the underlying quantum field theory, with the energy levels given by universal numbers times 1/L. We highlight the implications of a neighboring topological phase on the spectrum by studying the Ising* transition (i.e. the transition between a Z_{2} topological phase and a trivial paramagnet), in the example of the toric code in a longitudinal field, and advocate a phenomenological picture that provides qualitative insight into the operator content of the critical field theory.

  9. Inflation with finite temperature

    International Nuclear Information System (INIS)

    Bellini, M.; Michoacan, Univ. Michoacana de S.Nicola de Hidalgo

    1998-01-01

    In this work the inflationary scenario of the Universe with finite temperature is studied. In this context, thermal equilibrium is closely maintained at the end of inflation. The example of the de Sitter expansion is developed

  10. Testing hypotheses of earthquake occurrence

    Science.gov (United States)

    Kagan, Y. Y.; Jackson, D. D.; Schorlemmer, D.; Gerstenberger, M.

    2003-12-01

    We present a relatively straightforward likelihood method for testing those earthquake hypotheses that can be stated as vectors of earthquake rate density in defined bins of area, magnitude, and time. We illustrate the method as it will be applied to the Regional Earthquake Likelihood Models (RELM) project of the Southern California Earthquake Center (SCEC). Several earthquake forecast models are being developed as part of this project, and additional contributed forecasts are welcome. Various models are based on fault geometry and slip rates, seismicity, geodetic strain, and stress interactions. We would test models in pairs, requiring that both forecasts in a pair be defined over the same set of bins. Thus we offer a standard "menu" of bins and ground rules to encourage standardization. One menu category includes five-year forecasts of magnitude 5.0 and larger. Forecasts would be in the form of a vector of yearly earthquake rates on a 0.05 degree grid at the beginning of the test. Focal mechanism forecasts, when available, would be also be archived and used in the tests. The five-year forecast category may be appropriate for testing hypotheses of stress shadows from large earthquakes. Interim progress will be evaluated yearly, but final conclusions would be made on the basis of cumulative five-year performance. The second category includes forecasts of earthquakes above magnitude 4.0 on a 0.05 degree grid, evaluated and renewed daily. Final evaluation would be based on cumulative performance over five years. Other types of forecasts with different magnitude, space, and time sampling are welcome and will be tested against other models with shared characteristics. All earthquakes would be counted, and no attempt made to separate foreshocks, main shocks, and aftershocks. Earthquakes would be considered as point sources located at the hypocenter. For each pair of forecasts, we plan to compute alpha, the probability that the first would be wrongly rejected in favor of

  11. Exact finite-size corrections and corner free energies for the c=−2 universality class

    International Nuclear Information System (INIS)

    Izmailian, Nickolay; Kenna, Ralph; Guo, Wenan; Wu, Xintian

    2014-01-01

    We consider the partition functions of the anisotropic dimer model on the rectangular (2M−1)×(2N−1) lattice with (a) free and (b) cylindrical boundary conditions with a single monomer residing on the boundary. We express (a) and (b) in terms of a principal partition function with twisted boundary conditions. Based on these expressions, we derive the exact asymptotic expansions of the free energy for both cases (a) and (b). We confirm the conformal field theory prediction for the corner free energy of these models, and find the central charge is c=−2. We also show that the dimer model on the cylinder with an odd number of sites on the perimeter exhibits the same finite-size corrections as on the plane

  12. Deconfinement and universality in the 3DU(1) lattice gauge theory at finite temperature: study in the dual formulation

    Energy Technology Data Exchange (ETDEWEB)

    Borisenko, O.; Chelnokov, V. [Bogolyubov Institute for Theoretical Physics, National Academy of Sciences of Ukraine,UA-03680 Kiev (Ukraine); Gravina, M.; Papa, A. [Dipartimento di Fisica, Università della Calabria, and INFN - Gruppo collegato di Cosenza,I-87036 Arcavacata di Rende, Cosenza (Italy)

    2015-09-10

    We study analytically and numerically the three-dimensional U(1) lattice gauge theory at finite temperature in the dual formulation. For an appropriate disorder operator, we obtain the renormalization group equations describing the critical behavior of the model in the vicinity of the deconfinement phase transition. These equations are used to check the validity of the Svetitsky-Yaffe conjecture regarding the critical behavior of the lattice U(1) model. Furthermore, we perform numerical simulations of the model for N{sub t}=1,2,4,8 and compute, by a cluster algorithm, the dual correlation functions and the corresponding second moment correlation length. In this way we locate the position of the critical point and calculate critical indices.

  13. Exploring hypotheses in attitude control fault diagnosis

    Science.gov (United States)

    Bell, Benjamin

    1987-01-01

    A system which analyzes telemetry and evaluates hypotheses to explain any anomalies that are observed is described. Results achieved from a sample set of failure cases are presented, followed by a brief discussion of the benefits derived from this approach.

  14. Quantitative linking hypotheses for infant eye movements.

    Directory of Open Access Journals (Sweden)

    Daniel Yurovsky

    Full Text Available The study of cognitive development hinges, largely, on the analysis of infant looking. But analyses of eye gaze data require the adoption of linking hypotheses: assumptions about the relationship between observed eye movements and underlying cognitive processes. We develop a general framework for constructing, testing, and comparing these hypotheses, and thus for producing new insights into early cognitive development. We first introduce the general framework--applicable to any infant gaze experiment--and then demonstrate its utility by analyzing data from a set of experiments investigating the role of attentional cues in infant learning. The new analysis uncovers significantly more structure in these data, finding evidence of learning that was not found in standard analyses and showing an unexpected relationship between cue use and learning rate. Finally, we discuss general implications for the construction and testing of quantitative linking hypotheses. MATLAB code for sample linking hypotheses can be found on the first author's website.

  15. Non-linear finite element modeling

    DEFF Research Database (Denmark)

    Mikkelsen, Lars Pilgaard

    The note is written for courses in "Non-linear finite element method". The note has been used by the author teaching non-linear finite element modeling at Civil Engineering at Aalborg University, Computational Mechanics at Aalborg University Esbjerg, Structural Engineering at the University...

  16. Hypotheses about the psychological benefits of horses.

    Science.gov (United States)

    Kendall, Elizabeth; Maujean, Annick; Pepping, Christopher A; Wright, John J

    2014-01-01

    In the last few decades, therapeutic horse-riding has become recognized as a progressive form of therapy, particularly for people with disabilities. Although there is a substantial amount of literature that supports the physical benefit of therapeutic riding, only anecdotal evidence exists in relation to its psychological benefits. The purpose of this article is to develop hypotheses about the mechanisms by which therapeutic riding might have a beneficial psychological effect. These hypotheses can then be tested, leading to a more detailed knowledge base. PsychINFO, MEDLINE, PROQUEST, Scopus, Web of Science, and CINAHL. Data sources were searched for studies that (a) were related to the psychological effects of therapeutic horse-riding, (b) focused exclusively on therapeutic horse-riding, (c) described, explicitly or implicitly, the mechanism by which therapeutic riding had a beneficial psychological effect. Studies were limited to those published between 2008 and 2012. Data were extracted by two authors independently. Thirty articles met the inclusion criteria. Three potential hypotheses emerged from the literature, namely, (1) the psychological benefits of therapeutic riding are actually unrelated to the horse, (2) the horse provides a particularly positive context within which psychological gains are facilitated, and (3) the horse itself has specific therapeutic qualities that bring about unique changes not otherwise likely to occur. The challenge for researchers in this area is to design studies that adequately test these competing hypotheses. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. Adaptive hatching hypotheses do not explain asynchronous ...

    African Journals Online (AJOL)

    At the core of the suite of adaptive hatching hypotheses advanced to explain asynchronous hatching in birds is the assumption that if food is not limited then all the hatchlings will develop normally to adulthood. In this study Brown-headed Parrot Poicephalus cryptoxanthus chicks were hand fed and weighed on a daily basis.

  18. Methods for Evaluating Vocational Interest Structural Hypotheses.

    Science.gov (United States)

    Rounds, James; And Others

    1992-01-01

    Two forms of Holland's Hexagon Model (circular order and circumplex structure) are proposed and evaluated to demonstrate a randomization test of hypothesized order relations and confirmatory factor analysis. The models and methods are illustrated with correlation matrices based on the Unisex Edition of the ACT Interest Inventory. (Author/SK)

  19. Scientific'Laws','Hypotheses' and'Theories'

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 3; Issue 12. Scientific 'Laws', 'Hypotheses' and 'Theories' - How are They Related? J R Lakshmana Rao. General Article Volume 3 Issue 12 December 1998 pp 55-61. Fulltext. Click here to view fulltext PDF. Permanent link:

  20. Bayesian evaluation of inequality constrained hypotheses

    NARCIS (Netherlands)

    Gu, X.; Mulder, J.; Deković, M.; Hoijtink, H.

    2014-01-01

    Bayesian evaluation of inequality constrained hypotheses enables researchers to investigate their expectations with respect to the structure among model parameters. This article proposes an approximate Bayes procedure that can be used for the selection of the best of a set of inequality constrained

  1. Universe

    CERN Document Server

    Doudna, Kelly

    2015-01-01

    The Universe explores the science of what we see in the night sky. Kids will learn about the life cycle of a star, find out how our universe was created, explore nebulae, galaxies, black holes, giant stars and more. Engaging photos, exciting graphics, and a fun quiz at the end of each book will keep them learning. Aligned to Common Core Standards and correlated to state standards. Super Sandcastle is an imprint of Abdo Publishing, a division of ABDO.

  2. Singularity hypotheses a scientific and philosophical assessment

    CERN Document Server

    Moor, James; Søraker, Johnny; Steinhart, Eric

    2012-01-01

    Singularity Hypotheses: A Scientific and Philosophical Assessment offers authoritative, jargon-free essays and critical commentaries on accelerating technological progress and the notion of technological singularity. It focuses on conjectures about the intelligence explosion, transhumanism, and whole brain emulation. Recent years have seen a plethora of forecasts about the profound, disruptive impact that is likely to result from further progress in these areas. Many commentators however doubt the scientific rigor of these forecasts, rejecting them as speculative and unfounded. We therefore invited prominent computer scientists, physicists, philosophers, biologists, economists and other thinkers to assess the singularity hypotheses. Their contributions go beyond speculation, providing deep insights into the main issues and a balanced picture of the debate.

  3. Mapping Out Biogenetic Hypotheses by Chemical Synthesis.

    Science.gov (United States)

    Liffert, Raphael; Gademann, Karl

    2017-12-01

    Synthesis of natural products via their postulated or established biosynthetic intermediates ('biomimetic synthesis' or 'bio-inspired synthesis') has the power to identify both yet undiscovered intermediates and undiscovered mechanistic pathways for their formation. In this account, we report on our recent studies on unusual hypotheses for biosynthetic transformations, such as a late-stage aldol reaction (periconianone A), benzilic acid rearrangement (taiwaniaquinone H), a redox-neutral light-driven C-H activation (taiwaniaquinol A and cyclocoulterone), a hetero Diels-Alder reaction (obtusinones), aziridinium chemistry (Securinega alkaloids), and a [3+2] nitrone olefin cycloaddition (virosaine A). All these studies provided evidence on the molecular level for the feasibility of these transformations, and suggest that further studies investigating the relevance of these hypotheses in biological systems are warranted.

  4. New hypotheses regarding the Danish health puzzle.

    Science.gov (United States)

    Bakah, May; Raphael, Dennis

    2017-12-01

    Nordic welfare states have achieved admirable population health profiles as a result of public policies that provide economic and social security across the life course. Denmark has been an exception to this rule, as its life expectancies and infant mortality rates since the mid-1970s have lagged behind the other Nordic nations and, in the case of life expectancy, behind most Organisation for Economic Co-operation and Development nations. In this review paper, we identify a number of new hypotheses for why this may be the case. These hypotheses concern the health effects of neo-liberal restructuring of the economy and its institutions, the institution of flexi-security in Denmark's labour market and the influence of Denmark's tobacco and alcohol industries. Also of note is that Denmark experienced higher unemployment rates during its initial period of health stagnation, as well as its treatment of non-Western immigrants and high wealth inequality and, until recently, the fact that Denmark did not systematically address the issue of health inequalities. These hypotheses may serve as covering explanations for the usually provided accounts of elevated behavioural risks and psychosocial stress as being responsible for Denmark's health profile.

  5. finite induc

    Indian Academy of Sciences (India)

    com. Email: singh_shivaraj@rediffmail.com. In this article we provide a solution to a problem in the famous analysis book [1] by Rudin. It does not use trans- finite induction, and readers may find it more transpar- ent than the treatment in [2]. Here is ...

  6. Universe

    CERN Document Server

    2009-01-01

    The Universe, is one book in the Britannica Illustrated Science Library Series that is correlated to the science curriculum in grades 5-8. The Britannica Illustrated Science Library is a visually compelling set that covers earth science, life science, and physical science in 16 volumes.  Created for ages 10 and up, each volume provides an overview on a subject and thoroughly explains it through detailed and powerful graphics-more than 1,000 per volume-that turn complex subjects into information that students can grasp.  Each volume contains a glossary with full definitions for vocabulary help and an index.

  7. Universe

    CERN Document Server

    2011-01-01

    Updated for 2011, the Universe, is one book in the Britannica Illustrated Science Library Series that covers today's most popular science topics, from digital TV to microchips to touchscreens and beyond. Perennial subjects in earth science, life science, and physical science are all explored in detail. Amazing graphics-more than 1,000 per title-combined with concise summaries help students understand complex subjects. Correlated to the science curriculum in grades 5-9, each title also contains a glossary with full definitions for vocabulary.

  8. Constant conditional entropy and related hypotheses

    International Nuclear Information System (INIS)

    Ferrer-i-Cancho, Ramon; Dębowski, Łukasz; Moscoso del Prado Martín, Fermín

    2013-01-01

    Constant entropy rate (conditional entropies must remain constant as the sequence length increases) and uniform information density (conditional probabilities must remain constant as the sequence length increases) are two information theoretic principles that are argued to underlie a wide range of linguistic phenomena. Here we revise the predictions of these principles in the light of Hilberg’s law on the scaling of conditional entropy in language and related laws. We show that constant entropy rate (CER) and two interpretations for uniform information density (UID), full UID and strong UID, are inconsistent with these laws. Strong UID implies CER but the reverse is not true. Full UID, a particular case of UID, leads to costly uncorrelated sequences that are totally unrealistic. We conclude that CER and its particular cases are incomplete hypotheses about the scaling of conditional entropies. (letter)

  9. Assessing hypotheses about nesting site occupancy dynamics

    Science.gov (United States)

    Bled, Florent; Royle, J. Andrew; Cam, Emmanuelle

    2011-01-01

    Hypotheses about habitat selection developed in the evolutionary ecology framework assume that individuals, under some conditions, select breeding habitat based on expected fitness in different habitat. The relationship between habitat quality and fitness may be reflected by breeding success of individuals, which may in turn be used to assess habitat quality. Habitat quality may also be assessed via local density: if high-quality sites are preferentially used, high density may reflect high-quality habitat. Here we assessed whether site occupancy dynamics vary with site surrogates for habitat quality. We modeled nest site use probability in a seabird subcolony (the Black-legged Kittiwake, Rissa tridactyla) over a 20-year period. We estimated site persistence (an occupied site remains occupied from time t to t + 1) and colonization through two subprocesses: first colonization (site creation at the timescale of the study) and recolonization (a site is colonized again after being deserted). Our model explicitly incorporated site-specific and neighboring breeding success and conspecific density in the neighborhood. Our results provided evidence that reproductively "successful'' sites have a higher persistence probability than "unsuccessful'' ones. Analyses of site fidelity in marked birds and of survival probability showed that high site persistence predominantly reflects site fidelity, not immediate colonization by new owners after emigration or death of previous owners. There is a negative quadratic relationship between local density and persistence probability. First colonization probability decreases with density, whereas recolonization probability is constant. This highlights the importance of distinguishing initial colonization and recolonization to understand site occupancy. All dynamics varied positively with neighboring breeding success. We found evidence of a positive interaction between site-specific and neighboring breeding success. We addressed local

  10. Dental Hypotheses: Seeks to Publish Hypotheses from All Areas of Dentistry

    Directory of Open Access Journals (Sweden)

    Edward F. Rossomando

    2010-07-01

    Full Text Available Starting a new open access journal in a rapid growing scientific panorama is a severe challenge. However, the first issue of dental hypotheses is now history and the even skeptics can appreciate that dental hypotheses is a success - it is a journal of high quality that provides an outlet for publication of articles that encourage readers to question dental paradigms. But dental hypotheses readers might have noticed that the majority of the articles published in the first issue of dental hypotheses concern clinical dentistry. However, dental hypotheses editors recognize that there are many other areas in dentistry that present challenges and that our readers may offer suggestions for their solution. Some of these challenges relate to: dental education; digital dental technology; teledentistry and access to dental care; dental practice issues, such as, dental office design, dental office management, the slow rate of acceptance of innovative technology in the dental office; and issues related to innovation and dental entrepreneurship including intellectual property protection. Nevertheless, the dental profession faces many challenges - in many areas - and with the publication of dental hypotheses our profession has a venue for presentation of possible solutions. If you have developed a hypothesis that might help, please share it with your colleagues. As many have noted, the intellectual power of the global village in which we now live is formidable. The internet has provided the technology to bring us together and dental hypotheses has provided the venue. Please use it. New radical, speculative and non-mainstream scientific ideas are always welcome.

  11. Exact tensor hypercontraction: a universal technique for the resolution of matrix elements of local finite-range N-body potentials in many-body quantum problems.

    Science.gov (United States)

    Parrish, Robert M; Hohenstein, Edward G; Schunck, Nicolas F; Sherrill, C David; Martínez, Todd J

    2013-09-27

    Configuration-space matrix elements of N-body potentials arise naturally and ubiquitously in the Ritz-Galerkin solution of many-body quantum problems. For the common specialization of local, finite-range potentials, we develop the exact tensor hypercontraction method, which provides a quantized renormalization of the coordinate-space form of the N-body potential, allowing for a highly separable tensor factorization of the configuration-space matrix elements. This representation allows for substantial computational savings in chemical, atomic, and nuclear physics simulations, particularly with respect to difficult "exchangelike" contractions.

  12. Electroconvulsive therapy's mechanism of action: neuroendocrine hypotheses.

    Science.gov (United States)

    Haskett, Roger F

    2014-06-01

    Despite a range of etiological theories since the introduction of electroconvulsive therapy (ECT) more than 75 years ago, its mechanism of action remains poorly understood. The neuroendocrine hypothesis is based on the seizure-related release of hypothalamic hormones into the blood and cerebrospinal fluid and evidence of endocrine dysfunction in many patients with severe mood disorder. The specific effect of ECT was hypothesized to result from the transverse passage of current through the brain with direct stimulation of axial structures including the diencephalon. The prompt release of adrenocorticotropic hormone, cortisol, and prolactin into blood followed ECT with a return to pretreatment baseline levels in several hours. The elevated levels of hormones were absorbed by the cerebrospinal fluid, providing contact with brain cells and central nervous system structures. An apparently specific pattern of ECT-induced hormone changes, limited to prolactin and cortisol, suggested that ECT released a substance with dopaminergic antagonist and antipsychotic properties. As hypothalamic dysfunction is a key finding in endogenomorphic depression and the abnormal endocrine and physiological functions usually normalize with recovery, this led to a search for biological markers that would supplement clinical assessment of diagnosis and treatment response. One of these, the overnight dexamethasone suppression test found that 40% to 50% of melancholic depressed patients had abnormal results, whereas 90% of control patients suppressed normally. This was followed by a period of uncritical overenthusiasm followed by wholesale rejection of the clinical neuroendocrine strategies. Several key methodological issues received inadequate attention, and there have been calls to revisit this topic.

  13. Informative hypotheses: theory and practice for behavioral and social scientists

    National Research Council Canada - National Science Library

    Hoijtink, Herbert

    2012-01-01

    ... Hypotheses.There is currently a sound theoretical foundation for the evaluation of informative hypotheses using Bayes factors, p-values and the generalized order restricted information criterion...

  14. Electroconvulsive treatment: hypotheses about mechanisms of action

    Directory of Open Access Journals (Sweden)

    Roar eFosse

    2013-08-01

    Full Text Available No consensus has been reached on the mode of action of electroconvulsive treatment (ECT. We suggest that two features may aid in the delineation of the involved mechanisms. First, when effective, ECT would be likely to affect brain functions that are typically altered in its primary recipient group, people with severe depression. Central among these are the frontal and temporal lobes, the hypothalamus-pituitary-adrenal (HPA stress axis, and the mesocorticolimbic dopamine system. Second, the involved mechanisms should be affected for a time period that matches the average endurance of clinical effects, which is indicated to be several days to a few weeks. To identify effects upon frontal and temporal lobe functioning we reviewed human studies using EEG, PET, SPECT, and fMRI. Effects upon the HPA axis and the dopamine system were assessed by reviewing both human and animal studies. The EEG studies indicate that ECT decelerates neural activity in the frontal and temporal lobes (increased delta and theta wave activity for weeks to months. Comparable findings are reported from PET and SPECT studies, with reduced cerebral blood flow (functional deactivation for weeks to months after treatment. The EEG deceleration and functional deactivation following ECT are statistically associated with reduced depression scores. FMRI studies indicate that ECT flattens the pattern of activation and deactivation that is associated with cognitive task performance and alters cortical functional connectivity in the ultra slow frequency range. A common finding from human and animal studies is that electroconvulsive treatment acutely activates both the HPA axis and the dopamine system. In considering this evidence, we hypothesize that ECT affects the brain in a similar manner as severe stress or brain trauma which activates the HPA axis and the dopamine system and may compromise frontotemporal functions.

  15. On Consistent Nonparametric Statistical Tests of Symmetry Hypotheses

    Directory of Open Access Journals (Sweden)

    Jean-François Quessy

    2016-05-01

    Full Text Available Being able to formally test for symmetry hypotheses is an important topic in many fields, including environmental and physical sciences. In this paper, one concentrates on a large family of nonparametric tests of symmetry based on Cramér–von Mises statistics computed from empirical distribution and characteristic functions. These tests possess the highly desirable property of being universally consistent in the sense that they detect any kind of departure from symmetry as the sample size becomes large. The asymptotic behaviour of these test statistics under symmetry is deduced from the theory of first-order degenerate V-statistics. The issue of computing valid p-values is tackled using the multiplier bootstrap method suitably adapted to V-statistics, yielding elegant, easy-to-compute and quick procedures for testing symmetry. A special focus is put on tests of univariate symmetry, bivariate exchangeability and reflected symmetry; a simulation study indicates the good sampling properties of these tests. Finally, a framework for testing general symmetry hypotheses is introduced.

  16. Finite-temperature confinement transitions

    International Nuclear Information System (INIS)

    Svetitsky, B.

    1984-01-01

    The formalism of lattice gauge theory at finite temperature is introduced. The framework of universality predictions for critical behavior is outlined, and recent analytic work in this direction is reviewed. New Monte Carlo information for the SU(4) theory are represented, and possible results of the inclusion of fermions in the SU(3) theory are listed

  17. Locally Finite Root Supersystems

    OpenAIRE

    Yousofzadeh, Malihe

    2013-01-01

    We introduce the notion of locally finite root supersystems as a generalization of both locally finite root systems and generalized root systems. We classify irreducible locally finite root supersystems.

  18. On characters of finite groups

    CERN Document Server

    Broué, Michel

    2017-01-01

    This book explores the classical and beautiful character theory of finite groups. It does it by using some rudiments of the language of categories. Originally emerging from two courses offered at Peking University (PKU), primarily for third-year students, it is now better suited for graduate courses, and provides broader coverage than books that focus almost exclusively on groups. The book presents the basic tools, notions and theorems of character theory (including a new treatment of the control of fusion and isometries), and introduces readers to the categorical language at several levels. It includes and proves the major results on characteristic zero representations without any assumptions about the base field. The book includes a dedicated chapter on graded representations and applications of polynomial invariants of finite groups, and its closing chapter addresses the more recent notion of the Drinfeld double of a finite group and the corresponding representation of GL_2(Z).

  19. Production of verbs in base position by Dutch agrammatic speakers : Inflection versus finiteness

    NARCIS (Netherlands)

    Bastiaanse, Y.R.M.

    Several hypotheses have been formulated to predict the pattern of performance on finite verbs by agrammatic speakers. The present study is focused on finite and nonfinite verbs in base-position. Three finite verb forms (third person singular in past and present tense and third person plural in

  20. Predictive hypotheses are ineffectual in resolving complex biochemical systems.

    Science.gov (United States)

    Fry, Michael

    2018-03-20

    Scientific hypotheses may either predict particular unknown facts or accommodate previously-known data. Although affirmed predictions are intuitively more rewarding than accommodations of established facts, opinions divide whether predictive hypotheses are also epistemically superior to accommodation hypotheses. This paper examines the contribution of predictive hypotheses to discoveries of several bio-molecular systems. Having all the necessary elements of the system known beforehand, an abstract predictive hypothesis of semiconservative mode of DNA replication was successfully affirmed. However, in defining the genetic code whose biochemical basis was unclear, hypotheses were only partially effective and supplementary experimentation was required for its conclusive definition. Markedly, hypotheses were entirely inept in predicting workings of complex systems that included unknown elements. Thus, hypotheses did not predict the existence and function of mRNA, the multiple unidentified components of the protein biosynthesis machinery, or the manifold unknown constituents of the ubiquitin-proteasome system of protein breakdown. Consequently, because of their inability to envision unknown entities, predictive hypotheses did not contribute to the elucidation of cation theories remained the sole instrument to explain complex bio-molecular systems, the philosophical question of alleged advantage of predictive over accommodative hypotheses became inconsequential.

  1. Nilpotent -local finite groups

    Science.gov (United States)

    Cantarero, José; Scherer, Jérôme; Viruel, Antonio

    2014-10-01

    We provide characterizations of -nilpotency for fusion systems and -local finite groups that are inspired by known result for finite groups. In particular, we generalize criteria by Atiyah, Brunetti, Frobenius, Quillen, Stammbach and Tate.

  2. Testing hypotheses for differences between linear regression lines

    Science.gov (United States)

    Stanley J. Zarnoch

    2009-01-01

    Five hypotheses are identified for testing differences between simple linear regression lines. The distinctions between these hypotheses are based on a priori assumptions and illustrated with full and reduced models. The contrast approach is presented as an easy and complete method for testing for overall differences between the regressions and for making pairwise...

  3. Basic Finite Element Method

    International Nuclear Information System (INIS)

    Lee, Byeong Hae

    1992-02-01

    This book gives descriptions of basic finite element method, which includes basic finite element method and data, black box, writing of data, definition of VECTOR, definition of matrix, matrix and multiplication of matrix, addition of matrix, and unit matrix, conception of hardness matrix like spring power and displacement, governed equation of an elastic body, finite element method, Fortran method and programming such as composition of computer, order of programming and data card and Fortran card, finite element program and application of nonelastic problem.

  4. A survey of etiologic hypotheses among testicular cancer researchers

    DEFF Research Database (Denmark)

    Stang, A; Trabert, B; Rusner, C

    2015-01-01

    Basic research results can provide new ideas and hypotheses to be examined in epidemiological studies. We conducted a survey among testicular cancer researchers on hypotheses concerning the etiology of this malignancy. All researchers on the mailing list of Copenhagen Testis Cancer Workshops...... the plausibility of the suggested etiologic hypotheses on a scale of 1 (very implausible) to 10 (very plausible). This report describes the methodology of the survey, the score distributions by individual hypotheses, hypothesis group, and the participants' major research fields, and discuss the hypotheses...... and corresponding authors of PubMed-indexed articles identified by the search term 'testicular cancer' and published within 10 years (in total 2750 recipients) were invited to respond to an e-mail-based survey. Participants of the 8th Copenhagen Testis Cancer Workshop in May 2014 were subsequently asked to rate...

  5. Chiral crossover transition in a finite volume

    Science.gov (United States)

    Shi, Chao; Jia, Wenbao; Sun, An; Zhang, Liping; Zong, Hongshi

    2018-02-01

    Finite volume effects on the chiral crossover transition of strong interactions at finite temperature are studied by solving the quark gap equation within a cubic volume of finite size L. With the anti-periodic boundary condition, our calculation shows the chiral quark condensate, which characterizes the strength of dynamical chiral symmetry breaking, decreases as L decreases below 2.5 fm. We further study the finite volume effects on the pseudo-transition temperature {T}{{c}} of the crossover, showing a significant decrease in {T}{{c}} as L decreases below 3 fm. Supported by National Natural Science Foundation of China (11475085, 11535005, 11690030, 51405027), the Fundamental Research Funds for the Central Universities (020414380074), China Postdoctoral Science Foundation (2016M591808) and Open Research Foundation of State Key Lab. of Digital Manufacturing Equipment & Technology in Huazhong University of Science & Technology (DMETKF2015015)

  6. Composite Finite Sums

    KAUST Repository

    Alabdulmohsin, Ibrahim M.

    2018-03-07

    In this chapter, we extend the previous results of Chap. 2 to the more general case of composite finite sums. We describe what composite finite sums are and how their analysis can be reduced to the analysis of simple finite sums using the chain rule. We apply these techniques, next, on numerical integration and on some identities of Ramanujan.

  7. Finite Amplitude Ocean Waves

    Indian Academy of Sciences (India)

    IAS Admin

    plitude waves and finite amplitude waves. This article provides a brief introduction to finite amplitude wave theories. Some of the general characteristics of waves as well as the importance of finite amplitude wave theories are touched upon. 2. Small Amplitude Waves. The topmost and the lowest levels of the waves are re-.

  8. Patterns in body mass distributions: sifting among alternative hypotheses.

    Science.gov (United States)

    Allen, C R; Garmestani, A S; Havlicek, T D; Marquet, P A; Peterson, G D; Restrepo, C; Stow, C A; Weeks, B E

    2006-05-01

    Understanding how animals interact with their environment is critical for evaluating, mitigating and coping with anthropogenic alteration of Earth's biosphere. Researchers have attempted to understand some aspects of these interactions by examining patterns in animal body mass distributions. Energetic, phylogenetic, biogeographical, textural discontinuity and community interaction hypotheses have been advanced to explain observed patterns. Energetic and textural discontinuity hypotheses focus upon the allometry of resource use. The community interaction hypothesis contends that biotic interactions within assemblages of species are of primary importance. Biogeographical and phylogenetic hypotheses focus on the role of constraints on the organization of communities. This paper examines and organizes these various propositions about species body mass distributions and discusses the multiple competing hypotheses, how their predictions vary, and possible methods by which the hypotheses can be distinguished and tested. Each of the hypotheses is partial, and explains some elements of pattern in body mass distributions. The scale of appropriate application, relevance and interpretation varies among the hypotheses, and the mechanisms underlying observed patterns are likely to be multicausal and vary with scale.

  9. Cancer stem cell hypotheses: Impact on modern molecular ...

    Indian Academy of Sciences (India)

    CSCs) has been confirmed by a number of studies on experimental animal models. Nevertheless, it was shown that CSC hypotheses have several limitations and inconsistencies regarding the explanation of CSC origin, CSC identification and ...

  10. Site characterization and the method of multiple working hypotheses

    International Nuclear Information System (INIS)

    Fenster, D.F.; Cline, K.M.; Blair, J.A.; Stockey, J.

    1992-01-01

    Geologic investigations are necessary to determine whether a site is suitable for repository development and, if suitable, whether the site complies with regulatory requirements. Geologic processes and events often cannot be characterized without some degree of residual uncertainty. The method of multiple working hypotheses (MWH) is an approach in which alternative explanations for natural processes and/or events are identified, tested, and evaluated. This paper reports that in practice, several hypotheses may remain viable after all reasonable studies have been completed. Within the context of waste management and civil construction projects, all viable hypotheses that correspond with potential natural hazards must be analyzed in terms of adverse consequences to public health and safety, including radiological safety. For the repository licensing process, viable hypotheses remaining after the evaluation of data and quantification of uncertainty must be analyzed with regard to their consequences related to waste isolation. This approach can be used to determine whether additional studies are necessary to complete the license application

  11. HyQue: evaluating hypotheses using Semantic Web technologies

    Directory of Open Access Journals (Sweden)

    Callahan Alison

    2011-05-01

    Full Text Available Abstract Background Key to the success of e-Science is the ability to computationally evaluate expert-composed hypotheses for validity against experimental data. Researchers face the challenge of collecting, evaluating and integrating large amounts of diverse information to compose and evaluate a hypothesis. Confronted with rapidly accumulating data, researchers currently do not have the software tools to undertake the required information integration tasks. Results We present HyQue, a Semantic Web tool for querying scientific knowledge bases with the purpose of evaluating user submitted hypotheses. HyQue features a knowledge model to accommodate diverse hypotheses structured as events and represented using Semantic Web languages (RDF/OWL. Hypothesis validity is evaluated against experimental and literature-sourced evidence through a combination of SPARQL queries and evaluation rules. Inference over OWL ontologies (for type specifications, subclass assertions and parthood relations and retrieval of facts stored as Bio2RDF linked data provide support for a given hypothesis. We evaluate hypotheses of varying levels of detail about the genetic network controlling galactose metabolism in Saccharomyces cerevisiae to demonstrate the feasibility of deploying such semantic computing tools over a growing body of structured knowledge in Bio2RDF. Conclusions HyQue is a query-based hypothesis evaluation system that can currently evaluate hypotheses about the galactose metabolism in S. cerevisiae. Hypotheses as well as the supporting or refuting data are represented in RDF and directly linked to one another allowing scientists to browse from data to hypothesis and vice versa. HyQue hypotheses and data are available at http://semanticscience.org/projects/hyque.

  12. The revelation effect: A meta-analytic test of hypotheses.

    Science.gov (United States)

    Aßfalg, André; Bernstein, Daniel M; Hockley, William

    2017-12-01

    Judgments can depend on the activity directly preceding them. An example is the revelation effect whereby participants are more likely to claim that a stimulus is familiar after a preceding task, such as solving an anagram, than without a preceding task. We test conflicting predictions of four revelation-effect hypotheses in a meta-analysis of 26 years of revelation-effect research. The hypotheses' predictions refer to three subject areas: (1) the basis of judgments that are subject to the revelation effect (recollection vs. familiarity vs. fluency), (2) the degree of similarity between the task and test item, and (3) the difficulty of the preceding task. We use a hierarchical multivariate meta-analysis to account for dependent effect sizes and variance in experimental procedures. We test the revelation-effect hypotheses with a model selection procedure, where each model corresponds to a prediction of a revelation-effect hypothesis. We further quantify the amount of evidence for one model compared to another with Bayes factors. The results of this analysis suggest that none of the extant revelation-effect hypotheses can fully account for the data. The general vagueness of revelation-effect hypotheses and the scarcity of data were the major limiting factors in our analyses, emphasizing the need for formalized theories and further research into the puzzling revelation effect.

  13. Functionals of finite Riemann surfaces

    CERN Document Server

    Schiffer, Menahem

    1954-01-01

    This advanced monograph on finite Riemann surfaces, based on the authors' 1949-50 lectures at Princeton University, remains a fundamental book for graduate students. The Bulletin of the American Mathematical Society hailed the self-contained treatment as the source of ""a plethora of ideas, each interesting in its own right,"" noting that ""the patient reader will be richly rewarded."" Suitable for graduate-level courses, the text begins with three chapters that offer a development of the classical theory along historical lines, examining geometrical and physical considerations, existence theo

  14. Supersymmetric theories and finiteness

    International Nuclear Information System (INIS)

    Helayel-Neto, J.A.

    1989-01-01

    We attempt here to present a short survey of the all-order finite Lagrangian field theories known at present in four-and two-dimensional space-times. The question of the possible relevance of these ultraviolet finite models in the formulation of consistent unified frameworks for the fundamental forces is also addressed to. (author)

  15. Designs and finite geometries

    CERN Document Server

    1996-01-01

    Designs and Finite Geometries brings together in one place important contributions and up-to-date research results in this important area of mathematics. Designs and Finite Geometries serves as an excellent reference, providing insight into some of the most important research issues in the field.

  16. Finite-size scaling of survival probability in branching processes

    OpenAIRE

    Garcia-Millan, Rosalba; Font-Clos, Francesc; Corral, Alvaro

    2014-01-01

    Branching processes pervade many models in statistical physics. We investigate the survival probability of a Galton-Watson branching process after a finite number of generations. We reveal the finite-size scaling law of the survival probability for a given branching process ruled by a probability distribution of the number of offspring per element whose standard deviation is finite, obtaining the exact scaling function as well as the critical exponents. Our findings prove the universal behavi...

  17. Simple Finite Sums

    KAUST Repository

    Alabdulmohsin, Ibrahim M.

    2018-03-07

    We will begin our treatment of summability calculus by analyzing what will be referred to, throughout this book, as simple finite sums. Even though the results of this chapter are particular cases of the more general results presented in later chapters, they are important to start with for a few reasons. First, this chapter serves as an excellent introduction to what summability calculus can markedly accomplish. Second, simple finite sums are encountered more often and, hence, they deserve special treatment. Third, the results presented in this chapter for simple finite sums will, themselves, be used as building blocks for deriving the most general results in subsequent chapters. Among others, we establish that fractional finite sums are well-defined mathematical objects and show how various identities related to the Euler constant as well as the Riemann zeta function can actually be derived in an elementary manner using fractional finite sums.

  18. Sapwood allocation in tropical trees: a test of hypotheses

    NARCIS (Netherlands)

    Schippers, P.; Vlam, M.; Zuidema, P.A.; Sterck, F.J.

    2015-01-01

    Carbon allocation to sapwood in tropical canopy trees is a key process determining forest carbon sequestration, and is at the heart of tree growth and dynamic global vegetation models (DGVM). Several allocation hypotheses exist including those applying assumptions on fixed allocation, pipe model,

  19. Testing Hypotheses About Glacial Cycles Against the Observational Record

    DEFF Research Database (Denmark)

    Kaufmann, Robert; Juselius, Katarina

    2013-01-01

    We estimate an identified cointegrated vector autoregression (CVAR) model of the climate system to test hypotheses about the physical mechanisms that may drive glacial cycles during the late Pleistocene. Results indicate that a permanent doubling of CO2 generates a 11.1oC rise in Antarctic temepr...

  20. Twelve testable hypotheses on the geobiology of weathering

    Science.gov (United States)

    S.L. Brantley; J.P. Megonigal; F.N. Scatena; Z. Balogh-Brunstad; R.T. Barnes; M.A. Bruns; P. van Cappelen; K. Dontsova; H.E. Hartnett; A.S. Hartshorn; A. Heimsath; E. Herndon; L. Jin; C.K. Keller; J.R. Leake; W.H. McDowell; F.C. Meinzer; T.J. Mozdzer; S. Petsch; J. Pett-Ridge; K.S. Pretziger; P.A. Raymond; C.S. Riebe; K. Shumaker; A. Sutton-Grier; R. Walter; K. Yoo

    2011-01-01

    Critical Zone (CZ) research investigates the chemical, physical, and biological processes that modulate the Earth's surface. Here, we advance 12 hypotheses that must be tested to improve our understanding of the CZ: (1) Solar-to-chemical conversion of energy by plants regulates flows of carbon, water, and nutrients through plant-microbe soil networks, thereby...

  1. Addressing Moderated Mediation Hypotheses: Theory, Methods, and Prescriptions

    Science.gov (United States)

    Preacher, Kristopher J.; Rucker, Derek D.; Hayes, Andrew F.

    2007-01-01

    This article provides researchers with a guide to properly construe and conduct analyses of conditional indirect effects, commonly known as moderated mediation effects. We disentangle conflicting definitions of moderated mediation and describe approaches for estimating and testing a variety of hypotheses involving conditional indirect effects. We…

  2. Bayes Factor Approaches for Testing Interval Null Hypotheses

    Science.gov (United States)

    Morey, Richard D.; Rouder, Jeffrey N.

    2011-01-01

    Psychological theories are statements of constraint. The role of hypothesis testing in psychology is to test whether specific theoretical constraints hold in data. Bayesian statistics is well suited to the task of finding supporting evidence for constraint, because it allows for comparing evidence for 2 hypotheses against each another. One issue…

  3. Landscape moderation of biodiversity patterns and processes - eight hypotheses

    NARCIS (Netherlands)

    Tscharntke, T.; Tylianakis, J.M.; Rand, T.A.; Didham, R.K.; Fahrig, L.; Batary, P.; Bengtsson, J.; Clough, Y.; Crist, T.O.; Dormann, C.; Ewers, R.M.; Frund, J.; Holt, R.D.; Holzschuh, A.; Klein, A.M.; Kleijn, D.; Kremen, C.; Landis, D.A.; Laurance, W.F.; Lindenmayer, D.B.; Scherber, C.; Sodhi, N.; Steffan-Dewenter, I.; Thies, C.; Putten, van der W.H.; Westphal, C.

    2012-01-01

    Understanding how landscape characteristics affect biodiversity patterns and ecological processes at local and landscape scales is critical for mitigating effects of global environmental change. In this review, we use knowledge gained from human-modified landscapes to suggest eight hypotheses, which

  4. Causes of bat fatalities at wind turbines: Hypotheses and predictions

    Science.gov (United States)

    Cryan, P.M.; Barclay, R.M.R.

    2009-01-01

    Thousands of industrial-scale wind turbines are being built across the world each year to meet the growing demand for sustainable energy. Bats of certain species are dying at wind turbines in unprecedented numbers. Species of bats consistently affected by turbines tend to be those that rely on trees as roosts and most migrate long distances. Although considerable progress has been made in recent years toward better understanding the problem, the causes of bat fatalities at turbines remain unclear. In this synthesis, we review hypothesized causes of bat fatalities at turbines. Hypotheses of cause fall into 2 general categoriesproximate and ultimate. Proximate causes explain the direct means by which bats die at turbines and include collision with towers and rotating blades, and barotrauma. Ultimate causes explain why bats come close to turbines and include 3 general types: random collisions, coincidental collisions, and collisions that result from attraction of bats to turbines. The random collision hypothesis posits that interactions between bats and turbines are random events and that fatalities are representative of the bats present at a site. Coincidental hypotheses posit that certain aspects of bat distribution or behavior put them at risk of collision and include aggregation during migration and seasonal increases in flight activity associated with feeding or mating. A surprising number of attraction hypotheses suggest that bats might be attracted to turbines out of curiosity, misperception, or as potential feeding, roosting, flocking, and mating opportunities. Identifying, prioritizing, and testing hypothesized causes of bat collisions with wind turbines are vital steps toward developing practical solutions to the problem. ?? 2009 American Society of Mammalogists.

  5. Postulating hypotheses in experimental doctoral dissertations on Applied Linguistics: A qualitative investigation into rhetorical shifts and linguistic mechanisms

    Directory of Open Access Journals (Sweden)

    Jason Miin-Hwa Lim

    2014-03-01

    Full Text Available The extent to which research hypotheses need to be incorporated in experimental studies often becomes a subject of discussion among academics supervising the writing of theses and dissertations. While writers are concerned about how hypotheses can be strategically linked with other elements in research reports to effectively present an introductory chapter, instructors are considering ways of guiding learners to use the appropriate language in postulating research hypotheses. Using an analytical framework developed by Swales (1990 & 2004 and specialist informants’ qualitative data, this largely qualitative investigation looks into a corpus of experimental doctoral dissertations submitted to 32 American universities from 2001 to 2009 in order to ascertain (i the degree to which research hypotheses need to be presented in dissertation introductions, (ii how hypotheses are strategically linked with other rhetorical segments, and (iii the salient linguistic mechanisms used to achieve the communicative functions. This study has revealed (i how writers shift from pertinent communicative moves to the postulation of hypotheses, and (ii the gamut of major language choices employed to postulate these hypotheses. The findings can be used to prepare teaching materials that help learners comprehend and employ the rhetorical strategies and linguistic mechanisms needed in postulating hypotheses in research reports.

  6. A Note on TI-Subgroups of Finite Groups

    Indian Academy of Sciences (India)

    A subgroup of a finite group is called a TI-subgroup if H ∩ H x = 1 or for any x ∈ G . In this short note, the finite groups all of whose nonabelian subgroups are TI-subgroups are classified. Author Affiliations. Jiakuan Lu1 Linna Pang1. Department of Mathematics, Guangxi Normal University, Guangxi, Guilin 541004, ...

  7. A note on TI-subgroups of finite groups

    Indian Academy of Sciences (India)

    A subgroup of a finite group is called a TI-subgroup if H ∩ H x = 1 or for any x ∈ G . In this short note, the finite groups all of whose nonabelian subgroups are TI-subgroups are classified. Author Affiliations. Jiakuan Lu1 Linna Pang1. Department of Mathematics, Guangxi Normal University, Guangxi, Guilin 541004, ...

  8. Finite element study to quantify the relationship between masticatory stress and prognathism

    CSIR Research Space (South Africa)

    Kok, S

    2010-09-01

    Full Text Available In anthropology, the finite element method (FEM) is frequently applied to determine the validity of hypotheses concerning the adaptation of biological form to suit functionality. Different geometries are analysed, and based on the predicted...

  9. Finite elements and approximation

    CERN Document Server

    Zienkiewicz, O C

    2006-01-01

    A powerful tool for the approximate solution of differential equations, the finite element is extensively used in industry and research. This book offers students of engineering and physics a comprehensive view of the principles involved, with numerous illustrative examples and exercises.Starting with continuum boundary value problems and the need for numerical discretization, the text examines finite difference methods, weighted residual methods in the context of continuous trial functions, and piecewise defined trial functions and the finite element method. Additional topics include higher o

  10. Dissolution of hypotheses in biochemistry: three case studies.

    Science.gov (United States)

    Fry, Michael

    2016-12-01

    The history of biochemistry and molecular biology is replete with examples of erroneous theories that persisted for considerable lengths of time before they were rejected. This paper examines patterns of dissolution of three such erroneous hypotheses: The idea that nucleic acids are tetrads of the four nucleobases ('the tetranucleotide hypothesis'); the notion that proteins are collinear with their encoding genes in all branches of life; and the hypothesis that proteins are synthesized by reverse action of proteolytic enzymes. Analysis of these cases indicates that amassed contradictory empirical findings did not prompt critical experimental testing of the prevailing theories nor did they elicit alternative hypotheses. Rather, the incorrect models collapsed when experiments that were not purposely designed to test their validity exposed new facts.

  11. Furious Frederich: Nietzsche's neurosyphilis diagnosis and new hypotheses.

    Science.gov (United States)

    André, Charles; Rios, André Rangel

    2015-12-01

    The causes of Friedrich Nietzsche's mental breakdown in early 1889 and of the subsequent slow decay to end-stage dementia along ten years will possibly remain open to debate. The diagnosis of syphilitic dementia paralytica, based only on medical anamnesis and physical examination, was considered indisputable by Otto Binswanger. On the other hand, taking into account recently described diseases, selectively collected evidence lend some support to alternative hypotheses: basal forebrain meningioma, CADASIL, MELAS and frontotemporal dementia.

  12. Vaccines and Autism: A Tale of Shifting Hypotheses

    OpenAIRE

    Gerber, Jeffrey S.; Offit, Paul A.

    2009-01-01

    Although child vaccination rates remain high, some parental concern persists that vaccines might cause autism. Three specific hypotheses have been proposed: (1) the combination measles-mumps-rubella vaccine causes autism by damaging the intestinal lining, which allows the entrance of encephalopathic proteins; (2) thimerosal, an ethylmercury-containing preservative in some vaccines, is toxic to the central nervous system; and (3) the simultaneous administration of multiple vaccines overwhelms ...

  13. Evaluation of seven hypotheses for metamemory performance in rhesus monkeys

    Science.gov (United States)

    Basile, Benjamin M.; Schroeder, Gabriel R.; Brown, Emily Kathryn; Templer, Victoria L.; Hampton, Robert R.

    2014-01-01

    Knowing the extent to which nonhumans and humans share mechanisms for metacognition will advance our understanding of cognitive evolution and will improve selection of model systems for biomedical research. Some nonhuman species avoid difficult cognitive tests, seek information when ignorant, or otherwise behave in ways consistent with metacognition. There is agreement that some nonhuman animals “succeed” in these metacognitive tasks, but little consensus about the cognitive mechanisms underlying performance. In one paradigm, rhesus monkeys visually searched for hidden food when ignorant of the location of the food, but acted immediately when knowledgeable. This result has been interpreted as evidence that monkeys introspectively monitored their memory to adaptively control information seeking. However, convincing alternative hypotheses have been advanced that might also account for the adaptive pattern of visual searching. We evaluated seven hypotheses using a computerized task in which monkeys chose either to take memory tests immediately or to see the answer again before proceeding to the test. We found no evidence to support the hypotheses of behavioral cue association, rote response learning, expectancy violation, response competition, generalized search strategy, or postural mediation. In contrast, we repeatedly found evidence to support the memory monitoring hypothesis. Monkeys chose to see the answer when memory was poor, either from natural variation or experimental manipulation. We found limited evidence that monkeys also monitored the fluency of memory access. Overall, the evidence indicates that rhesus monkeys can use memory strength as a discriminative cue for information seeking, consistent with introspective monitoring of explicit memory. PMID:25365530

  14. Supersymmetry at finite temperature

    International Nuclear Information System (INIS)

    Clark, T.E.; Love, S.T.

    1983-01-01

    Finite-temperature supersymmetry (SUSY) is characterized by unbroken Ward identities for SUSY variations of ensemble averages of Klein-operator inserted imaginary time-ordered products of fields. Path-integral representations of these products are defined and the Feynman rules in superspace are given. The finite-temperature no-renormalization theorem is derived. Spontaneously broken SUSY at zero temperature is shown not to be restored at high temperature. (orig.)

  15. Hypothesized eye movements of neurolinguistic programming: a statistical artifact.

    Science.gov (United States)

    Farmer, A; Rooney, R; Cunningham, J R

    1985-12-01

    Neurolinguistic programming's hypothesized eye-movements were measured independently from videotapes of 30 subjects, aged 15 to 76 yr., who were asked to recall visual pictures, recorded audio sounds, and textural objects. chi 2 indicated that subjects' responses were significantly different from those predicted. When chi 2 comparisons were weighted by number of eye positions assigned to each modality (3 visual, 3 auditory, 1 kinesthetic), subjects' responses did not differ significantly from the expected pattern. These data indicate that the eye-movement hypothesis may represent randomly occurring rather than sensory-modality-related positions.

  16. Fuzzy Hypotheses Testing in the Framework of Fuzzy Logic

    Czech Academy of Sciences Publication Activity Database

    Holeňa, Martin

    2004-01-01

    Roč. 145, - (2004), s. 229-252 ISSN 0165-0114 R&D Projects: GA AV ČR IAA1030004; GA MŠk OC 274.001 Grant - others:COST(XE) Action 274 TARSKI Institutional research plan: CEZ:AV0Z1030915 Keywords : non-classical logics * fuzzy predicate calculus * basic fuzzy logic * generalized quantifiers * fuzzy statistics and data analysis * vague hypotheses * vague significance level * method Guha Subject RIV: BB - Applied Statistics , Operational Research Impact factor: 0.734, year: 2004

  17. Vaccines and autism: a tale of shifting hypotheses.

    Science.gov (United States)

    Gerber, Jeffrey S; Offit, Paul A

    2009-02-15

    Although child vaccination rates remain high, some parental concern persists that vaccines might cause autism. Three specific hypotheses have been proposed: (1) the combination measles-mumps-rubella vaccine causes autism by damaging the intestinal lining, which allows the entrance of encephalopathic proteins; (2) thimerosal, an ethylmercury-containing preservative in some vaccines, is toxic to the central nervous system; and (3) the simultaneous administration of multiple vaccines overwhelms or weakens the immune system. We will discuss the genesis of each of these theories and review the relevant epidemiological evidence.

  18. Seed dormancy and germination—emerging mechanisms and new hypotheses

    Science.gov (United States)

    Nonogaki, Hiroyuki

    2014-01-01

    Seed dormancy has played a significant role in adaptation and evolution of seed plants. While its biological significance is clear, molecular mechanisms underlying seed dormancy induction, maintenance and alleviation still remain elusive. Intensive efforts have been made to investigate gibberellin and abscisic acid metabolism in seeds, which greatly contributed to the current understanding of seed dormancy mechanisms. Other mechanisms, which might be independent of hormones, or specific to the seed dormancy pathway, are also emerging from genetic analysis of “seed dormancy mutants.” These studies suggest that chromatin remodeling through histone ubiquitination, methylation and acetylation, which could lead to transcription elongation or gene silencing, may play a significant role in seed dormancy regulation. Small interfering RNA and/or long non-coding RNA might be a trigger of epigenetic changes at the seed dormancy or germination loci, such as DELAY OF GERMINATION1. While new mechanisms are emerging from genetic studies of seed dormancy, novel hypotheses are also generated from seed germination studies with high throughput gene expression analysis. Recent studies on tissue-specific gene expression in tomato and Arabidopsis seeds, which suggested possible “mechanosensing” in the regulatory mechanisms, advanced our understanding of embryo-endosperm interaction and have potential to re-draw the traditional hypotheses or integrate them into a comprehensive scheme. The progress in basic seed science will enable knowledge translation, another frontier of research to be expanded for food and fuel production. PMID:24904627

  19. Finite Discrete Gabor Analysis

    DEFF Research Database (Denmark)

    Søndergaard, Peter Lempel

    2007-01-01

    on the real line to be well approximated by finite and discrete Gabor frames. This method of approximation is especially attractive because efficient numerical methods exists for doing computations with finite, discrete Gabor systems. This thesis presents new algorithms for the efficient computation of finite......, discrete Gabor coefficients. Reconstruction of a signal from its Gabor coefficients is done by the use of a so-called dual window. This thesis presents a number of iterative algorithms to compute dual and self-dual windows. The Linear Time Frequency Toolbox is a Matlab/Octave/C toolbox for doing basic...... discrete time/frequency and Gabor analysis. It is intended to be both an educational and a computational tool. The toolbox was developed as part of this Ph.D. project to provide a solid foundation for the field of computational Gabor analysis....

  20. Products of Finite Groups

    CERN Document Server

    Ballester-Bolinches, Adolfo; Asaad, Mohamed

    2010-01-01

    The study of finite groups factorised as a product of two or more subgroups has become a subject of great interest during the last years with applications not only in group theory, but also in other areas like cryptography and coding theory. It has experienced a big impulse with the introduction of some permutability conditions. The aim of this book is to gather, order, and examine part of this material, including the latest advances made, give some new approach to some topics, and present some new subjects of research in the theory of finite factorised groups.

  1. Towards Self-Learning Based Hypotheses Generation in Biomedical Text Domain.

    Science.gov (United States)

    Gopalakrishnan, Vishrawas; Jha, Kishlay; Xun, Guangxu; Ngo, Hung Q; Zhang, Aidong

    2017-12-26

    The overwhelming amount of research articles in the domain of bio-medicine might cause important connections to remain unnoticed. Literature Based Discovery is a sub-field within biomedical text mining that peruses these articles to formulate high confident hypotheses on possible connections between medical concepts. Although many alternate methodologies have been proposed over the last decade, they still suffer from scalability issues. The primary reason, apart from the dense inter-connections between biological concepts, is the absence of information on the factors that lead to the edge-formation. In this work, we formulate this problem as a collaborative filtering task and leverage a relatively new concept of word-vectors to learn and mimic the implicit edge-formation process. Along with single-class classifier, we prune the search-space of redundant and irrelevant hypotheses to increase the efficiency of the system and at the same time maintaining and in some cases even boosting the overall accuracy. We show that our proposed framework is able to prune up to 90% of the hypotheses while still retaining high recall in top-K results. This level of efficiency enables the discovery algorithm to look for higher-order hypotheses, something that was infeasible until now. Furthermore, the generic formulation allows our approach to be agile to performboth open and closed discovery.We also experimentally validate that the core data-structures upon which the system bases its decision has a high concordance with the opinion of the experts.This coupled with the ability to understand the edge formation process provides us with interpretable results without any manual intervention. The relevant JAVA codes are available at: https://github.com/vishrawas/Medline-Code_v2. vishrawa@buffalo.edukishlayj@buffalo.edu. Supplementary data are available at Bioinformatics online. © The Author (2017). Published by Oxford University Press. All rights reserved. For Permissions, please email

  2. Hypotheses to explain the origin of species in Amazonia

    Directory of Open Access Journals (Sweden)

    J. Haffer

    Full Text Available The main hypotheses proposed to explain barrier formation separating populations and causing the differentiation of species in Amazonia during the course of geological history are based on different factors, as follow: (1 Changes in the distribution of land and sea or in the landscape due to tectonic movements or sea level fluctuations (Paleogeography hypothesis, (2 the barrier effect of Amazonian rivers (River hypothesis, (3 a combination of the barrier effect of broad rivers and vegetational changes in northern and southern Amazonia (River-refuge hypothesis, (4 the isolation of humid rainforest blocks near areas of surface relief in the periphery of Amazonia separated by dry forests, savannas and other intermediate vegetation types during dry climatic periods of the Tertiary and Quaternary (Refuge hypothesis, (5 changes in canopy-density due to climatic reversals (Canopy-density hypothesis (6 the isolation and speciation of animal populations in small montane habitat pockets around Amazonia due to climatic fluctuations without major vegetational changes (Museum hypothesis, (7 competitive species interactions and local species isolations in peripheral regions of Amazonia due to invasion and counterinvasion during cold/warm periods of the Pleistocene (Disturbance-vicariance hypothesis and (8 parapatric speciation across steep environmental gradients without separation of the respective populations (Gradient hypothesis. Several of these hypotheses probably are relevant to a different degree for the speciation processes in different faunal groups or during different geological periods. The basic paleogeography model refers mainly to faunal differentiation during the Tertiary and in combination with the Refuge hypothesis. Milankovitch‡ cycles leading to global main hypotheses proposed to explain barrier formation separating populations and causing the differentiation of species in Amazonia during the course of geological history are based on

  3. Hypotheses to explain the origin of species in Amazonia.

    Science.gov (United States)

    Haffer, J

    2008-11-01

    The main hypotheses proposed to explain barrier formation separating populations and causing the differentiation of species in Amazonia during the course of geological history are based on different factors, as follow: (1) Changes in the distribution of land and sea or in the landscape due to tectonic movements or sea level fluctuations (Paleogeography hypothesis), (2) the barrier effect of Amazonian rivers (River hypothesis), (3) a combination of the barrier effect of broad rivers and vegetational changes in northern and southern Amazonia (River-refuge hypothesis), (4) the isolation of humid rainforest blocks near areas of surface relief in the periphery of Amazonia separated by dry forests, savannas and other intermediate vegetation types during dry climatic periods of the Tertiary and Quaternary (Refuge hypothesis), (5) changes in canopy-density due to climatic reversals (Canopy-density hypothesis) (6) the isolation and speciation of animal populations in small montane habitat pockets around Amazonia due to climatic fluctuations without major vegetational changes (Museum hypothesis), (7) competitive species interactions and local species isolations in peripheral regions of Amazonia due to invasion and counterinvasion during cold/warm periods of the Pleistocene (Disturbance-vicariance hypothesis) and (8) parapatric speciation across steep environmental gradients without separation of the respective populations (Gradient hypothesis). Several of these hypotheses probably are relevant to a different degree for the speciation processes in different faunal groups or during different geological periods. The basic paleogeography model refers mainly to faunal differentiation during the Tertiary and in combination with the Refuge hypothesis. Milankovitch cycles leading to global main hypotheses proposed to explain barrier formation separating populations and causing the differentiation of species in Amazonia during the course of geological history are based on different

  4. Psychohistorical Hypotheses on Japan's History of Hostility Towards China.

    Science.gov (United States)

    Wang, Bo; Rudmin, Floyd

    2016-01-01

    The accelerating tensions and military posturing between Japan and China have created a serious crisis with a danger of a catastrophic war. The purpose of this paper is to summarize the events of the current crisis, and to put it in the context of Japan's long history of hostility to China and repeated attempts at conquest. The historical record shows that Japan has attacked China at least seven times, even though China has never attacked Japan. The irrationality of Japan's behavior is demonstrated by the repetition of this hostile behavior despite the enormous human and economic costs that Japan has suffered because of it. The irrationality of Japan's militarism suggests that psychological explanations may be required to understand this phenomenon. Several hypotheses are proposed, including 1) projected paranoid aggression, 2) collective Zeigarnik compulsion, 3) perceived weakness exciting aggression, 4) national inferiority feelings, 5) cultural narcissism, and 6) Oedipal-like hatred of a parent culture.

  5. Political Participation Online: The Replacement and the Mobilisation Hypotheses Revisited

    DEFF Research Database (Denmark)

    Jensen, Jakob Linaa

    2013-01-01

    of the Internet. The pure replacement hypothesis is rejected. Instead, it is found that the Internet still supplements rather than replaces other media, even among heavy Internet users. The Internet is one among several media used by ‘media omnivores’, and political participation online supplements rather than...... participation, efficacy and social capital seem to have less impact on online political participation. In the end, these findings are related to more overall discussions on the democratising potential of the Internet.......This article discusses the state of political participation online more than ten years after the Internet’s great popular breakthrough as an everyday medium. Denmark is used as a case study to critically re-examine the frequently discussed replacement and mobilisation hypotheses on behalf...

  6. Two hypotheses on the causes of male homosexuality and paedophilia.

    Science.gov (United States)

    James, William H

    2006-11-01

    This note considers two hypotheses on the causes of homosexuality and paedophilia in men, viz. the hypotheses of maternal immunity and of postnatal learning. According to the maternal immune hypothesis, there is progressive immunization of some mothers to male-specific antigens by each succeeding male fetus, and there are concomitantly increasing effects of anti-male antibodies on the sexual differentiation of the brain in each succeeding male fetus. An attempt is made to assess the status of this hypothesis within immunology. Knowledge of the properties of anti-male antibodies is meagre and there has been little direct experimentation on them, let alone on their effects on the developing male fetal brain. Moreover until the relevant antigens are identified, it will not be possible to test mothers of male homosexuals or paedophiles for the presence of such antibodies. Yet until this experimentation has been done, it would seem premature to regard the hypothesis as more than a very provisional explanatory tool. The evidence in relation to the postnatal learning hypothesis is quite different. There is an abundance of data suggesting that male homosexuals and paedophiles report having experienced more sexual abuse (however defined) in childhood (CSA) than do heterosexual controls. The question revolves round the interpretation of these data. Many (though not all) of these studies are correlational and thus subject to the usual qualifications concerning such data. However, there are grounds for supposing that some of the reports are veridical, and there is support from a longitudinal study reporting a small but significant increase in paedophilia in adulthood following CSA. To summarize: most boys who experience CSA do not later develop into homosexuals or paedophiles. However, the available evidence suggests that a few do so as a result of the abuse.

  7. Testing evolutionary hypotheses for phenotypic divergence using landscape genetics.

    Science.gov (United States)

    Funk, W Chris; Murphy, Melanie A

    2010-02-01

    Understanding the evolutionary causes of phenotypic variation among populations has long been a central theme in evolutionary biology. Several factors can influence phenotypic divergence, including geographic isolation, genetic drift, divergent natural or sexual selection, and phenotypic plasticity. But the relative importance of these factors in generating phenotypic divergence in nature is still a tantalizing and unresolved problem in evolutionary biology. The origin and maintenance of phenotypic divergence is also at the root of many ongoing debates in evolutionary biology, such as the extent to which gene flow constrains adaptive divergence (Garant et al. 2007) and the relative importance of genetic drift, natural selection, and sexual selection in initiating reproductive isolation and speciation (Coyne & Orr 2004). In this issue, Wang & Summers (2010) test the causes of one of the most fantastic examples of phenotypic divergence in nature: colour pattern divergence among populations of the strawberry poison frog (Dendrobates pumilio) in Panama and Costa Rica (Fig. 1). This study provides a beautiful example of the use of the emerging field of landscape genetics to differentiate among hypotheses for phenotypic divergence. Using landscape genetic analyses, Wang & Summers were able to reject the hypotheses that colour pattern divergence is due to isolation-by-distance (IBD) or landscape resistance. Instead, the hypothesis left standing is that colour divergence is due to divergent selection, in turn driving reproductive isolation among populations with different colour morphs. More generally, this study provides a wonderful example of how the emerging field of landscape genetics, which has primarily been applied to questions in conservation and ecology, now plays an essential role in evolutionary research.

  8. About hypotheses and paradigms: exploring the Discreetness-Chance Paradigm.

    Science.gov (United States)

    Kaellis, Eugene

    2006-01-01

    Hypotheses generally conform to paradigms which, over time, change, usually tardily, after they have become increasingly difficult to sustain under the impact of non-conforming evidence and alternative hypotheses, but more important, when they no longer are comfortably ensconced in the surrounding social-economic-political-cultural milieu. It is asserted that this milieu is the most important factor in shaping scientific theorizing. Some examples are cited: the rejection of the evidence that the world orbits around the sun (suspected by Pythagoras) in favor of centuries-long firm adherence to the Ptolemaic geocentric system; the early acceptance of Natural Selection in spite of its tautological essence and only conjectural supporting evidence, because it justified contemporaneous social-political ideologies as typified by, e.g., Spencer and Malthus. Economic, social, and cultural factors are cited as providing the ground, i.e., ideational substrate, for what is cited as the Discreetness-Chance Paradigm (DCP), that has increasingly dominated physics, biology, and medicine for over a century and which invokes small, discrete packets of energy/matter (quanta, genes, microorganisms, aberrant cells) functioning within an environment of statistical, not determined, causality. There is speculation on a possible paradigmatic shift from the DCP, which has fostered the proliferation, parallel with ("splitting") taxonomy, of alleged individual disease entities, their diagnoses, and, when available, their specific remedies, something particularly prominent in, e.g., psychiatry's Diagnostic and Statistical Manual, a codified compendium of alleged mental and behavioral disorders, but evident in any textbook of diagnosis and treatment of physical ailments. This presumed paradigm shift may be reflected in Western medicine, presently increasingly empirical and atomized, towards a growing acceptance of a more generalized, subject-oriented, approach to health and disease, a non

  9. Hypotheses about geoglyphs at Nasca, Peru: new discoveries

    Directory of Open Access Journals (Sweden)

    Jaroslav Klokočník

    2016-07-01

    Full Text Available The known hypotheses about the reasons why the geoglyphs in the Nasca and Palpa region of Peru were created are many: roads/paths, rituals/ceremonials, use of hallucinogens, astronomical meaning, influence of extraterrestrials, underground water… and so on. We present a new hypothesis, formulated by J. Sonnek (first published in 2011 in the context of all previous hypotheses.1 Sonnek explains the geoglyphs as tidied work areas for the production of rope and nets, although he goes much further than Stierlin. This eccentric hypothesis now has not only experimental but also archaeological and ethnographical support, which is presented here. Geoglyphs of a special shape were discovered in the pampas; they may represent technical objects – different types of ‘rope twisters’. Following this idea, Sonnek made technical devices (using today’s materials and tested them in practice; they work perfectly, see his YouTube videos.2 In November 2012, wooden pieces, which may be the remnants of ropemaking, were collected from the pampa near the towns of Nasca and Palpa, in vicinity of these hypothetic ropemaking places. Radiocarbon testing by 14C standardized radio-carbon age according to Stuiver-Polach convention and Accelerator Mass Spectroscopy (AMS of these wood pieces shows the age to be in a wide range from Early Nasca to the 17th century (and to our epoch with a fake geoglyph, too, thus supporting (but surely not proving the new hypothesis. Moreover, in the Quechua language, the word huasca, waskha (read: uasca means a rope or cord or place where these are produced. This word is very similar to ‘nasca’.

  10. Pursuing the method of multiple working hypotheses for hydrological modeling

    Science.gov (United States)

    Clark, M. P.; Kavetski, D.; Fenicia, F.

    2012-12-01

    Ambiguities in the representation of environmental processes have manifested themselves in a plethora of hydrological models, differing in almost every aspect of their conceptualization and implementation. The current overabundance of models is symptomatic of an insufficient scientific understanding of environmental dynamics at the catchment scale, which can be attributed to difficulties in measuring and representing the heterogeneity encountered in natural systems. This presentation advocates using the method of multiple working hypotheses for systematic and stringent testing of model alternatives in hydrology. We discuss how the multiple hypothesis approach provides the flexibility to formulate alternative representations (hypotheses) describing both individual processes and the overall system. When combined with incisive diagnostics to scrutinize multiple model representations against observed data, this provides hydrologists with a powerful and systematic approach for model development and improvement. Multiple hypothesis frameworks also support a broader coverage of the model hypothesis space and hence improve the quantification of predictive uncertainty arising from system and component non-identifiabilities. As part of discussing the advantages and limitations of multiple hypothesis frameworks, we critically review major contemporary challenges in hydrological hypothesis-testing, including exploiting different types of data to investigate the fidelity of alternative process representations, accounting for model structure ambiguities arising from major uncertainties in environmental data, quantifying regional differences in dominant hydrological processes, and the grander challenge of understanding the self-organization and optimality principles that may functionally explain and describe the heterogeneities evident in most environmental systems. We assess recent progress in these research directions, and how new advances are possible using multiple hypothesis

  11. Undecidability and finite automata

    NARCIS (Netherlands)

    Endrullis, Jörg; Shallit, Jeffrey; Smith, Tim

    2017-01-01

    Using a novel rewriting problem, we show that several natural decision problems about finite automata are undecidable (i.e., recursively unsolvable). In contrast, we also prove three related problems are decidable. We apply one result to prove the undecidability of a related problem about

  12. Robust RBF Finite Automata

    Czech Academy of Sciences Publication Activity Database

    Šorel, Michal; Šíma, Jiří

    2004-01-01

    Roč. 62, - (2004), s. 93-110 ISSN 0925-2312 R&D Projects: GA AV ČR IAB2030007; GA MŠk LN00A056 Keywords : radial basis function * neural network * finite automaton * Boolean circuit * computational power Subject RIV: BA - General Mathematics Impact factor: 0.641, year: 2004

  13. Inside finite elements

    CERN Document Server

    Weiser, Martin

    2016-01-01

    All relevant implementation aspects of finite element methods are discussed in this book. The focus is on algorithms and data structures as well as on their concrete implementation. Theory is covered as far as it gives insight into the construction of algorithms. Throughout the exercises a complete FE-solver for scalar 2D problems will be implemented in Matlab/Octave.

  14. Finite unified models

    Energy Technology Data Exchange (ETDEWEB)

    Kapetanakis, D. (Technische Univ. Muenchen, Garching (Germany). Physik Dept.); Mondragon, M. (Technische Univ. Muenchen, Garching (Germany). Physik Dept.); Zoupanos, G. (National Technical Univ., Athens (Greece). Physics Dept.)

    1993-09-01

    We present phenomenologically viable SU(5) unified models which are finite to all orders before the spontaneous symmetry breaking. In the case of two models with three families the top quark mass is predicted to be 178.8 GeV. (orig.)

  15. Finite unified models

    International Nuclear Information System (INIS)

    Kapetanakis, D.; Mondragon, M.; Zoupanos, G.

    1993-01-01

    We present phenomenologically viable SU(5) unified models which are finite to all orders before the spontaneous symmetry breaking. In the case of two models with three families the top quark mass is predicted to be 178.8 GeV. (orig.)

  16. Finiteness and GUTs

    International Nuclear Information System (INIS)

    Kapetanakis, D.; Mondragon, M.

    1993-01-01

    It is shown how to obtain phenomenologically viable SU(5) unified models which are finite to all orders before the spontaneous symmetry breaking. A very interesting feature of the models with three families is that they predict the top quark mass to be around 178 GeV. 16 refs

  17. Migration and fertility in Malaysia: a tale of two hypotheses.

    Science.gov (United States)

    Bach, R L

    1981-01-01

    2 hypotheses that are prevalent in the migration and fertility literature, are tested using data from the 1966-67 West Malaysian Family Survey. Particular attention is paid to conceptual and methodological frameworks of research and study of sociodemographic trends in Malaysia. Noting that confusion exists in previous studies of migration and fertility, especially in regards to comparing migrants and nonmigrants with residence background and migration experience, the 2 hypotheses are discussed: 1) the assimilation hypothesis in which a) place of childrearing (origin) is an important influence on fertility behavior (e.g. geographical differentials of fertility norms, family size preference), b) residence during childbearing period (destination) is a residential status that may be related to fertility (e.g. values, expectation, economic opportunities, contraceptive availability), and c) the assimilitation process can be expressed as a weighted combination of specific influences of either place of childrearing or childbearing; 2) the migration hypothesis in which a) there is something intrinsic to geographical shifts that cannot be accounted for by mere knowledge of the place of origin or destination, b) individuals are selected by age, education, ethnicity, and motivation, and c) the impact of migration is selected on specific fertility-related characteristics, e.g. the postponment of childbearing. The data in the study are drawn from a KAP-style national survey which utilized a stratified (size of place) probability sampling frame of 5457 married Malaysian women between 15 and 45 years of age. In view of the hypothesis, the identification of area of early socialization and adult experience measures the area of greatest influence on individual fertility behavior. Measures of migration are advantageous to approximating the true timing of migration and fertility in a causal ordering. To conclude, Bach suggests that fertility levels of migrants can be accounted for

  18. Masticatory-stress hypotheses and the supraorbital region of primates.

    Science.gov (United States)

    Hylander, W L; Picq, P G; Johnson, K R

    1991-09-01

    The purpose of this study is to test various masticatory-stress hypotheses about the evolution and function of well-developed browridges of higher primates. This was done by measuring and analyzing patterns of in vivo bone strain recorded from three-element rosette strain gages bonded to the supraorbital region and to other portions of the bony face of Macaca fascicularis and Papio anubis during mastication and incision. The magnitude and direction of the principal strains recorded support Endo's hypothesis that the supraorbital region during mastication and incision is bent in the frontal plane (Endo, 1966). Our data do not, however, support his hypothesis that the supraorbital region is bent more during incision than during mastication. The data also demonstrate that overall levels of supraorbital strain are not larger in more prognathic subjects. Most importantly, the data indicate that the supraorbital region of nonhuman catarrhines is strained very little during mastication and incision. This indicates that there is much more supraorbital bone than is necessary both to counter masticatory loads and to provide an adequate safety factor to failure for these loads. This in turn suggests that the macaque and baboon browridges can be considerably reduced in size and still maintain these required structural characteristics. Thus, our experiments provide no support whatsoever for those hypotheses that directly link browridge morphology to masticatory stress (cf. Endo, 1966; Russell, 1983, 1985). A recent review of Endo's original work indicates that this latter statement is also true for humans (Picq and Hylander, 1989). We conclude, therefore, that there is no good reason to believe that enlarged browridges in living and/or fossil primates are structural adaptations to counter intense masticatory forces. The evolution of browridge morphology in primates is best explained on the basis of factors related to the position of the brain relative to the orbits (Moss and

  19. Nonlinear, finite deformation, finite element analysis

    Science.gov (United States)

    Nguyen, Nhung; Waas, Anthony M.

    2016-06-01

    The roles of the consistent Jacobian matrix and the material tangent moduli, which are used in nonlinear incremental finite deformation mechanics problems solved using the finite element method, are emphasized in this paper, and demonstrated using the commercial software ABAQUS standard. In doing so, the necessity for correctly employing user material subroutines to solve nonlinear problems involving large deformation and/or large rotation is clarified. Starting with the rate form of the principle of virtual work, the derivations of the material tangent moduli, the consistent Jacobian matrix, the stress/strain measures, and the objective stress rates are discussed and clarified. The difference between the consistent Jacobian matrix (which, in the ABAQUS UMAT user material subroutine is referred to as DDSDDE) and the material tangent moduli ( C e ) needed for the stress update is pointed out and emphasized in this paper. While the former is derived based on the Jaumann rate of the Kirchhoff stress, the latter is derived using the Jaumann rate of the Cauchy stress. Understanding the difference between these two objective stress rates is crucial for correctly implementing a constitutive model, especially a rate form constitutive relation, and for ensuring fast convergence. Specifically, the implementation requires the stresses to be updated correctly. For this, the strains must be computed directly from the deformation gradient and corresponding strain measure (for a total form model). Alternatively, the material tangent moduli derived from the corresponding Jaumann rate of the Cauchy stress of the constitutive relation (for a rate form model) should be used. Given that this requirement is satisfied, the consistent Jacobian matrix only influences the rate of convergence. Its derivation should be based on the Jaumann rate of the Kirchhoff stress to ensure fast convergence; however, the use of a different objective stress rate may also be possible. The error associated

  20. Origin of honeycombs: Testing the hydraulic and case hardening hypotheses

    Science.gov (United States)

    Bruthans, Jiří; Filippi, Michal; Slavík, Martin; Svobodová, Eliška

    2018-02-01

    Cavernous weathering (cavernous rock decay) is a global phenomenon, which occurs in porous rocks around the world. Although honeycombs and tafoni are considered to be the most common products of this complex process, their origin and evolution are as yet not fully understood. The two commonly assumed formation hypotheses - hydraulic and case hardening - were tested to elucidate the origin of honeycombs on sandstone outcrops in a humid climate. Mechanical and hydraulic properties of the lips (walls between adjacent pits) and backwalls (bottoms of pits) of the honeycombs were determined via a set of established and novel approaches. While the case hardening hypothesis was not supported by the determinations of either tensile strength, drilling resistance or porosity, the hydraulic hypothesis was clearly supported by field measurements and laboratory tests. Fluorescein dye visualization of capillary zone, vapor zone, and evaporation front upon their contact, demonstrated that the evaporation front reaches the honeycomb backwalls under low water flow rate, while the honeycomb lips remain dry. During occasional excessive water flow events, however, the evaporation front may shift to the lips, while the backwalls become moist as a part of the capillary zone. As the zone of evaporation corresponds to the zone of potential salt weathering, it is the spatial distribution of the capillary and vapor zones which dictates whether honeycombs are created or the rock surface is smoothed. A hierarchical model of factors related to the hydraulic field was introduced to obtain better insights into the process of cavernous weathering.

  1. A perspective on SIDS pathogenesis. The hypotheses: plausibility and evidence

    Directory of Open Access Journals (Sweden)

    Goldwater Paul N

    2011-05-01

    Full Text Available Abstract Several theories of the underlying mechanisms of Sudden Infant Death Syndrome (SIDS have been proposed. These theories have born relatively narrow beach-head research programs attracting generous research funding sustained for many years at expense to the public purse. This perspective endeavors to critically examine the evidence and bases of these theories and determine their plausibility; and questions whether or not a safe and reasoned hypothesis lies at their foundation. The Opinion sets specific criteria by asking the following questions: 1. Does the hypothesis take into account the key pathological findings in SIDS? 2. Is the hypothesis congruent with the key epidemiological risk factors? 3. Does it link 1 and 2? Falling short of any one of these answers, by inference, would imply insufficient grounds for a sustainable hypothesis. Some of the hypotheses overlap, for instance, notional respiratory failure may encompass apnea, prone sleep position, and asphyxia which may be seen to be linked to co-sleeping. For the purposes of this paper, each element will be assessed on the above criteria.

  2. Exploration of miRNA families for hypotheses generation.

    KAUST Repository

    Kamanu, T.K.

    2013-10-15

    Technological improvements have resulted in increased discovery of new microRNAs (miRNAs) and refinement and enrichment of existing miRNA families. miRNA families are important because they suggest a common sequence or structure configuration in sets of genes that hint to a shared function. Exploratory tools to enhance investigation of characteristics of miRNA families and the functions of family-specific miRNA genes are lacking. We have developed, miRNAVISA, a user-friendly web-based tool that allows customized interrogation and comparisons of miRNA families for hypotheses generation, and comparison of per-species chromosomal distribution of miRNA genes in different families. This study illustrates hypothesis generation using miRNAVISA in seven species. Our results unveil a subclass of miRNAs that may be regulated by genomic imprinting, and also suggest that some miRNA families may be species-specific, as well as chromosome- and/or strand-specific.

  3. Drug-Resistant Epilepsy: Multiple Hypotheses, Few Answers

    Directory of Open Access Journals (Sweden)

    Fei Tang

    2017-07-01

    Full Text Available Epilepsy is a common neurological disorder that affects over 70 million people worldwide. Despite the recent introduction of new antiseizure drugs (ASDs, about one-third of patients with epilepsy have seizures refractory to pharmacotherapy. Early identification of patients who will become refractory to ASDs could help direct such patients to appropriate non-pharmacological treatment, but the complexity in the temporal patterns of epilepsy could make such identification difficult. The target hypothesis and transporter hypothesis are the most cited theories trying to explain refractory epilepsy, but neither theory alone fully explains the neurobiological basis of pharmacoresistance. This review summarizes evidence for and against several major theories, including the pharmacokinetic hypothesis, neural network hypothesis, intrinsic severity hypothesis, gene variant hypothesis, target hypothesis, and transporter hypothesis. The discussion is mainly focused on the transporter hypothesis, where clinical and experimental data are discussed on multidrug transporter overexpression, substrate profiles of ASDs, mechanism of transporter upregulation, polymorphisms of transporters, and the use of transporter inhibitors. Finally, future perspectives are presented for the improvement of current hypotheses and the development of treatment strategies as guided by the current understanding of refractory epilepsy.

  4. Testing Adaptive Hypotheses of Convergence with Functional Landscapes: A Case Study of Bone-Cracking Hypercarnivores

    Science.gov (United States)

    Tseng, Zhijie Jack

    2013-01-01

    Morphological convergence is a well documented phenomenon in mammals, and adaptive explanations are commonly employed to infer similar functions for convergent characteristics. I present a study that adopts aspects of theoretical morphology and engineering optimization to test hypotheses about adaptive convergent evolution. Bone-cracking ecomorphologies in Carnivora were used as a case study. Previous research has shown that skull deepening and widening are major evolutionary patterns in convergent bone-cracking canids and hyaenids. A simple two-dimensional design space, with skull width-to-length and depth-to-length ratios as variables, was used to examine optimized shapes for two functional properties: mechanical advantage (MA) and strain energy (SE). Functionality of theoretical skull shapes was studied using finite element analysis (FEA) and visualized as functional landscapes. The distribution of actual skull shapes in the landscape showed a convergent trend of plesiomorphically low-MA and moderate-SE skulls evolving towards higher-MA and moderate-SE skulls; this is corroborated by FEA of 13 actual specimens. Nevertheless, regions exist in the landscape where high-MA and lower-SE shapes are not represented by existing species; their vacancy is observed even at higher taxonomic levels. Results highlight the interaction of biomechanical and non-biomechanical factors in constraining general skull dimensions to localized functional optima through evolution. PMID:23734244

  5. Supersymmetry at finite temperature

    International Nuclear Information System (INIS)

    Oliveira, M.W. de.

    1986-01-01

    The consequences of the incorporation of finite temperature effects in fields theories are investigated. Particularly, we consider the sypersymmetric non-linear sigma model, calculating the effective potencial in the large N limit. Initially, we present the 1/N expantion formalism and, for the O(N) model of scalar field, we show the impossibility of spontaneous symmetry breaking. Next, we study the same model at finite temperature and in the presence of conserved charges (the O(N) symmetry's generator). We conclude that these conserved charges explicitly break the symmetry. We introduce a calculation method for the thermodynamic potential of the theory in the presence of chemical potentials. We present an introduction to Supersymmetry in the aim of describing some important concepts for the treatment at T>0. We show that Suppersymmetry is broken for any T>0, in opposition to what one expects, by the solution of the Hierachy Problem. (author) [pt

  6. Endocardial tip cells in the human embryo - facts and hypotheses.

    Directory of Open Access Journals (Sweden)

    Mugurel C Rusu

    Full Text Available Experimental studies regarding coronary embryogenesis suggest that the endocardium is a source of endothelial cells for the myocardial networks. As this was not previously documented in human embryos, we aimed to study whether or not endothelial tip cells could be correlated with endocardial-dependent mechanisms of sprouting angiogenesis. Six human embryos (43-56 days were obtained and processed in accordance with ethical regulations; immunohistochemistry was performed for CD105 (endoglin, CD31, CD34, α-smooth muscle actin, desmin and vimentin antibodies. Primitive main vessels were found deriving from both the sinus venosus and aorta, and were sought to be the primordia of the venous and arterial ends of cardiac microcirculation. Subepicardial vessels were found branching into the outer ventricular myocardium, with a pattern of recruiting α-SMA+/desmin+ vascular smooth muscle cells and pericytes. Endothelial sprouts were guided by CD31+/CD34+/CD105+/vimentin+ endothelial tip cells. Within the inner myocardium, we found endothelial networks rooted from endocardium, guided by filopodia-projecting CD31+/CD34+/CD105+/ vimentin+ endocardial tip cells. The myocardial microcirculatory bed in the atria was mostly originated from endocardium, as well. Nevertheless, endocardial tip cells were also found in cardiac cushions, but they were not related to cushion endothelial networks. A general anatomical pattern of cardiac microvascular embryogenesis was thus hypothesized; the arterial and venous ends being linked, respectively, to the aorta and sinus venosus. Further elongation of the vessels may be related to the epicardium and subepicardial stroma and the intramyocardial network, depending on either endothelial and endocardial filopodia-guided tip cells in ventricles, or mostly on endocardium, in atria.

  7. Twelve testable hypotheses on the geobiology of weathering.

    Science.gov (United States)

    Brantley, S L; Megonigal, J P; Scatena, F N; Balogh-Brunstad, Z; Barnes, R T; Bruns, M A; Van Cappellen, P; Dontsova, K; Hartnett, H E; Hartshorn, A S; Heimsath, A; Herndon, E; Jin, L; Keller, C K; Leake, J R; McDowell, W H; Meinzer, F C; Mozdzer, T J; Petsch, S; Pett-Ridge, J; Pregitzer, K S; Raymond, P A; Riebe, C S; Shumaker, K; Sutton-Grier, A; Walter, R; Yoo, K

    2011-03-01

    Critical Zone (CZ) research investigates the chemical, physical, and biological processes that modulate the Earth's surface. Here, we advance 12 hypotheses that must be tested to improve our understanding of the CZ: (1) Solar-to-chemical conversion of energy by plants regulates flows of carbon, water, and nutrients through plant-microbe soil networks, thereby controlling the location and extent of biological weathering. (2) Biological stoichiometry drives changes in mineral stoichiometry and distribution through weathering. (3) On landscapes experiencing little erosion, biology drives weathering during initial succession, whereas weathering drives biology over the long term. (4) In eroding landscapes, weathering-front advance at depth is coupled to surface denudation via biotic processes. (5) Biology shapes the topography of the Critical Zone. (6) The impact of climate forcing on denudation rates in natural systems can be predicted from models incorporating biogeochemical reaction rates and geomorphological transport laws. (7) Rising global temperatures will increase carbon losses from the Critical Zone. (8) Rising atmospheric P(CO2) will increase rates and extents of mineral weathering in soils. (9) Riverine solute fluxes will respond to changes in climate primarily due to changes in water fluxes and secondarily through changes in biologically mediated weathering. (10) Land use change will impact Critical Zone processes and exports more than climate change. (11) In many severely altered settings, restoration of hydrological processes is possible in decades or less, whereas restoration of biodiversity and biogeochemical processes requires longer timescales. (12) Biogeochemical properties impart thresholds or tipping points beyond which rapid and irreversible losses of ecosystem health, function, and services can occur. © 2011 Blackwell Publishing Ltd.

  8. Finite-size scaling of survival probability in branching processes.

    Science.gov (United States)

    Garcia-Millan, Rosalba; Font-Clos, Francesc; Corral, Álvaro

    2015-04-01

    Branching processes pervade many models in statistical physics. We investigate the survival probability of a Galton-Watson branching process after a finite number of generations. We derive analytically the existence of finite-size scaling for the survival probability as a function of the control parameter and the maximum number of generations, obtaining the critical exponents as well as the exact scaling function, which is G(y)=2ye(y)/(e(y)-1), with y the rescaled distance to the critical point. Our findings are valid for any branching process of the Galton-Watson type, independently of the distribution of the number of offspring, provided its variance is finite. This proves the universal behavior of the finite-size effects in branching processes, including the universality of the metric factors. The direct relation to mean-field percolation is also discussed.

  9. Presence of quantum diffusion in two dimensions: Universal resistance at the superconductor-insulator transition

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, M.P.A.; Grinstein, G. (IBM Research Division, Thomas J. Watson Research Center, Yorktown Heights, New York 10598 (US)); Girvin, S.M. (Physics Department, Swain Hall West 117, Indiana University, Bloomington, Indiana 47405 (USA))

    1990-01-29

    We argue that whenever the transition between the insulating and superconducting phases of a disordered two-dimensional Fermi system at zero temperature ({ital T}=0) is continuous, the system behaves like a normal metal right at the transition; i.e., the resistance has a finite, nonzero value at {ital T}=0. This value is {ital universal}---independent of all microscopic details. These features, consistent with recent measurements on disordered films, are hypothesized to apply to other 2D transitions at {ital T}=0, such as Anderson localization with spin-orbit coupling, and the quantum Hall effect.

  10. Using Finite Element Method

    Directory of Open Access Journals (Sweden)

    M.H.R. Ghoreishy

    2008-02-01

    Full Text Available This research work is devoted to the footprint analysis of a steel-belted radial tyre (185/65R14 under vertical static load using finite element method. Two models have been developed in which in the first model the tread patterns were replaced by simple ribs while the second model was consisted of details of the tread blocks. Linear elastic and hyper elastic (Arruda-Boyce material models were selected to describe the mechanical behavior of the reinforcing and rubbery parts, respectively. The above two finite element models of the tyre were analyzed under inflation pressure and vertical static loads. The second model (with detailed tread patterns was analyzed with and without friction effect between tread and contact surfaces. In every stage of the analysis, the results were compared with the experimental data to confirm the accuracy and applicability of the model. Results showed that neglecting the tread pattern design not only reduces the computational cost and effort but also the differences between computed deformations do not show significant changes. However, more complicated variables such as shape and area of the footprint zone and contact pressure are affected considerably by the finite element model selected for the tread blocks. In addition, inclusion of friction even in static state changes these variables significantly.

  11. A note on 2-nilpotence of finite groups

    Indian Academy of Sciences (India)

    JIANGTAO SHI1 and CUI ZHANG1,2,∗. 1School of Mathematics and Information Science, Yantai University, ... Keywords. Finite group; 2-nilpotent group; quaternion-free. 1. Introduction. Let G be a finite group and P a Sylow 2-subgroup of G. Recall that G is said to be 2- nilpotent if there exists a normal subgroup K of G such ...

  12. Universal Solutions of Quantum Dynamical Yang-Baxter Equations

    CERN Document Server

    Arnaudon, Daniel; Ragoucy, E; Roche, P; Roche, Ph.

    1998-01-01

    We construct a universal trigonometric solution of the Gervais-Neveu-Felder equation in the case of finite dimensional simple Lie algebras and finite dimensional contragredient simple Lie superalgebras.

  13. Declining scaup populations: issues, hypotheses, and research needs

    Science.gov (United States)

    Austin, J.E.; Afton, A.D.; Anderson, M.G.; Clark, R.G.; Custer, Christine M.; Lawrence, J.S.; Pollard, J.B.; Ringelman, J.K.

    2000-01-01

    The population estimate for greater (Aythya marila) and lesser (Aythya affinis) scaup (combined) has declined dramatically since the early 1980s to record lows in 1998. The 1998 estimate of 3.47 million scaup is far below the goal of 6.3 million set in the North American Waterfowl Management Plan (NAWMP), causing concern among biologists and hunters. We summarize issuesof concern, hypotheses for factors contributing to the population decline, and research and management needs recommended by participants of the Scaup Workshop, held in September 1999. We believe that contaminants, lower female survival, and reduced recruitment due to changes in food resources or breedingground habitats are primary factors contributing to the decline. These factors are not mutually exclusive but likely interact across seasons. Workshop participants identified seven action items. We need to further delineate where declines in breeding populations have occurred, with a primary focus on the western Canadian boreal forest, where declines appear to be most pronounced. Productivity in various areas and habitats throughout the breeding range needs to be assessed by conducting retrospective analyses of existing data and by intensive field studies at broad and local scales. Annual and seasonal survival rates need to be determined in order to assess the role of harvest or natural mortality. Effects of contaminants on reproduction, female body condition, and behavior must be investigated. Use, distribution, and role of food resources relative to body condition and reproduction need to be examined to better understand seasonal dynamics of nutrient reserves and the role in reproductive success. Affiliations among breeding, migration, and wintering areas must be assessed in order to understand differential exposure to harvest or contaminants, and differential reproductive success and recruitment. Biologists and agencies need to gather and improve information needed to manage greater and lesser

  14. Hypotheses on the a priori rational necessity of quantum mechanics

    Directory of Open Access Journals (Sweden)

    Gerard Gouesbet

    2010-12-01

    Full Text Available There is a huge number of laments concerning the lack of intelligibility of quantum mechanics. Some ingredients of quantum mechanics may however be possibly understood by referring to first principles, that is to say to basic principles (or postulates which are clear and distinct to the intuition. In particular, if we rely on a first principle called non-singularity principle, which may be viewed as a hypothesis, we claim that quantum mechanics can be viewed as the a priori consequence of a rational demand. The status of the non-singularity principle, obvious to most physicists, may however be criticized, on the basis that there is no universal intuition and that any statement is in principle revisable.

  15. Assaults on Inmates and Staff by Perpetrators of Intimate Partner Homicide: An Examination of Competing Hypotheses.

    Science.gov (United States)

    Sorensen, Jonathan R; Vigen, Mark P; Woods, S O; Williams, Bradley D

    2015-11-01

    The current study presents the results of an analysis of serious and assaultive prison rule violating behavior among male perpetrators of intimate partner homicide (IPH). Data on prison rule violations were collected from a sample of 189 inmates convicted of IPH in a large, southern prison system. The study focused on the degree of continuity in violent behavior among IPH offenders from the community to the prison setting. The current study tested hypotheses derived from both the feminist perspective (FP) and the general violence perspective (GVP). As a group, IPH offenders were better behaved in prison than other incarcerated homicide offenders, thereby offering some support for the FP. However, the lower level of assaultive behavior among the group was not universal. Characteristics associated with continued violent offending in the prison environment were the same as those found in previous studies of incarcerated homicide offenders, thereby lending greater support to the GVP. © The Author(s) 2014.

  16. A Review of Hypothesized Determinants Associated with Bighorn Sheep (Ovis canadensis Die-Offs

    Directory of Open Access Journals (Sweden)

    David S. Miller

    2012-01-01

    Full Text Available Multiple determinants have been hypothesized to cause or favor disease outbreaks among free-ranging bighorn sheep (Ovis canadensis populations. This paper considered direct and indirect causes of mortality, as well as potential interactions among proposed environmental, host, and agent determinants of disease. A clear, invariant relationship between a single agent and field outbreaks has not yet been documented, in part due to methodological limitations and practical challenges associated with developing rigorous study designs. Therefore, although there is a need to develop predictive models for outbreaks and validated mitigation strategies, uncertainty remains as to whether outbreaks are due to endemic or recently introduced agents. Consequently, absence of established and universal explanations for outbreaks contributes to conflict among wildlife and livestock stakeholders over land use and management practices. This example illustrates the challenge of developing comprehensive models for understanding and managing wildlife diseases in complex biological and sociological environments.

  17. A Review of Hypothesized Determinants Associated with Bighorn Sheep (Ovis canadensis) Die-Offs

    Science.gov (United States)

    Miller, David S.; Hoberg, Eric; Weiser, Glen; Aune, Keith; Atkinson, Mark; Kimberling, Cleon

    2012-01-01

    Multiple determinants have been hypothesized to cause or favor disease outbreaks among free-ranging bighorn sheep (Ovis canadensis) populations. This paper considered direct and indirect causes of mortality, as well as potential interactions among proposed environmental, host, and agent determinants of disease. A clear, invariant relationship between a single agent and field outbreaks has not yet been documented, in part due to methodological limitations and practical challenges associated with developing rigorous study designs. Therefore, although there is a need to develop predictive models for outbreaks and validated mitigation strategies, uncertainty remains as to whether outbreaks are due to endemic or recently introduced agents. Consequently, absence of established and universal explanations for outbreaks contributes to conflict among wildlife and livestock stakeholders over land use and management practices. This example illustrates the challenge of developing comprehensive models for understanding and managing wildlife diseases in complex biological and sociological environments. PMID:22567546

  18. How the mainstream limits the spreading of alternative hypotheses

    Science.gov (United States)

    Kalenda, Pavel

    2014-05-01

    that prof. Djuric had tried for more than 10 years to publish this article in various peer-reviewed journals. So, prof. Djuric got into the official book (list) of "scientific dissidents" among hundreds of other professors and doctors of science (De Climont 2012). These "scientific dissidents" do not have access to established journals and may possibly publish privately or at best on the web in marginal journals whose list was published by De Climont (2012). Such a marginal journal in the field of geophysics and geology is New Concepts in Global Tectonics. This journal has been established because the current hypothesis about the movement of the continents due to convection currents in the mantle becomes under the weight of new observation quite untenable. 4) Scientific consensus History has known many hypotheses that were accepted as proven truth but later, in the light of new knowledge, they completely failed. - No one has the right to decide which scientific hypotheses will be accepted and which will not get into print. Perhaps the worst situation is in climatology (due to global effects and impacts), when the plenary session of IPCC consensually stated that the current global warming was mainly due to the human activity. References De Climont, J. (2012): The worldwide list of dissident scientists. http://astrojan.hostei.com/droa.htm. Djurič, J. (2006): Unification Of Gravitation And Electromagnetism. http://jovandjuric.tripod.com/ David H. Douglass, John R. Christy, Benjamin D. Pearson and S. Fred Singer (2007): A comparison of tropical temperature trends with model predictions. International Journal of Climatology, Volume 28, Issue 13, 15 November 2008, Pages: 1693-1701. http://onlinelibrary.wiley.com/doi/10.1002/joc.1651/pdf. Einstein, A. : List of scientific publications by Albert Einstein. /wiki/List_of_scientific_publications_by_Albert_Einstein. Kolínský, P., Valenta, J. and Gaždová, R. (2012): Seismicity, groundwater level variations and earth tides in

  19. Combinatorics of finite sets

    CERN Document Server

    Anderson, Ian

    2011-01-01

    Coherent treatment provides comprehensive view of basic methods and results of the combinatorial study of finite set systems. The Clements-Lindstrom extension of the Kruskal-Katona theorem to multisets is explored, as is the Greene-Kleitman result concerning k-saturated chain partitions of general partially ordered sets. Connections with Dilworth's theorem, the marriage problem, and probability are also discussed. Each chapter ends with a helpful series of exercises and outline solutions appear at the end. ""An excellent text for a topics course in discrete mathematics."" - Bulletin of the Ame

  20. Optical Finite Element Processor

    Science.gov (United States)

    Casasent, David; Taylor, Bradley K.

    1986-01-01

    A new high-accuracy optical linear algebra processor (OLAP) with many advantageous features is described. It achieves floating point accuracy, handles bipolar data by sign-magnitude representation, performs LU decomposition using only one channel, easily partitions and considers data flow. A new application (finite element (FE) structural analysis) for OLAPs is introduced and the results of a case study presented. Error sources in encoded OLAPs are addressed for the first time. Their modeling and simulation are discussed and quantitative data are presented. Dominant error sources and the effects of composite error sources are analyzed.

  1. Solving hyperbolic equations with finite volume methods

    CERN Document Server

    Vázquez-Cendón, M Elena

    2015-01-01

    Finite volume methods are used in numerous applications and by a broad multidisciplinary scientific community. The book communicates this important tool to students, researchers in training and academics involved in the training of students in different science and technology fields. The selection of content is based on the author’s experience giving PhD and master courses in different universities. In the book the introduction of new concepts and numerical methods go together with simple exercises, examples and applications that contribute to reinforce them. In addition, some of them involve the execution of MATLAB codes. The author promotes an understanding of common terminology with a balance between mathematical rigor and physical intuition that characterizes the origin of the methods. This book aims to be a first contact with finite volume methods. Once readers have studied it, they will be able to follow more specific bibliographical references and use commercial programs or open source software withi...

  2. Mathematics and computer science: coping with finiteness.

    Science.gov (United States)

    Knuth, D E

    1976-12-11

    By presenting these examples, I have tried to illustrate four main points. 1) Finite numbers can be really enormous, and the known universe is very small. Therefore the distinction between finite and infinite is not as relevant as the distinction between realistic and unrealistic. 2) In many cases there are subtle ways to solve very large problems quickly, in spite of the fact that they appear at first to require examination of too many possibilities. 3) There are also cases where we can prove that a fairly natural problem is intrinsically hard, far beyond our conceivable capabilities. 4) It takes a good deal of skill to decide whether a given problem is in the easy or hard class; but even if a problem does turn out to be hard there are useful and interesting ways to change it into one that can be done satisfactorily.

  3. Finite Element Analysis of Honeycomb Impact Attenuator

    Science.gov (United States)

    Yang, Seung-Yong; Choi, Seung-Kyu; Kim, Nohyu

    To participate in Student Formula Society of Automotive Engineers (SAE) competitions, it is necessary to build an impact attenuator that would give an average deceleration not to exceed 20g when it runs into a rigid wall. Students can use numerical simulations or experimental test data to show that their car satisfies this safety requirement. A student group to study formula cars at the Korea University of Technology and Education has designed a vehicle to take part in a SAE competition, and a honeycomb structure was adopted as the impact attenuator. In this paper, finite element calculations were carried out to investigate the dynamic behavior of the honeycomb attenuator. Deceleration and deformation behaviors were studied. Effect of the yield strength was checked by comparing the numerical results. ABAQUS/Explicit finite element code was used.

  4. Thermal quench at finite 't Hooft coupling

    Directory of Open Access Journals (Sweden)

    H. Ebrahim

    2016-03-01

    Full Text Available Using holography we have studied thermal electric field quench for infinite and finite 't Hooft coupling constant. The set-up we consider here is D7-brane embedded in (α′ corrected AdS-black hole background. It is well-known that due to a time-dependent electric field on the probe brane, a time-dependent current will be produced and it will finally relax to its equilibrium value. We have studied the effect of different parameters of the system on equilibration time. As the most important results, for massless fundamental matter, we have observed a universal behaviour in the rescaled equilibration time in the very fast quench regime for different values of the temperature and α′ correction parameter. It seems that in the slow quench regime the system behaves adiabatically. We have also observed that the equilibration time decreases in finite 't Hooft coupling limit.

  5. Finiteness of corner vortices

    Science.gov (United States)

    Kalita, Jiten C.; Biswas, Sougata; Panda, Swapnendu

    2018-04-01

    Till date, the sequence of vortices present in the solid corners of steady internal viscous incompressible flows was thought to be infinite. However, the already existing and most recent geometric theories on incompressible viscous flows that express vortical structures in terms of critical points in bounded domains indicate a strong opposition to this notion of infiniteness. In this study, we endeavor to bridge the gap between the two opposing stream of thoughts by diagnosing the assumptions of the existing theorems on such vortices. We provide our own set of proofs for establishing the finiteness of the sequence of corner vortices by making use of the continuum hypothesis and Kolmogorov scale, which guarantee a nonzero scale for the smallest vortex structure possible in incompressible viscous flows. We point out that the notion of infiniteness resulting from discrete self-similarity of the vortex structures is not physically feasible. Making use of some elementary concepts of mathematical analysis and our own construction of diametric disks, we conclude that the sequence of corner vortices is finite.

  6. The Determining Finite Automata Process

    Directory of Open Access Journals (Sweden)

    M. S. Vinogradova

    2017-01-01

    Full Text Available The theory of formal languages widely uses finite state automata both in implementation of automata-based approach to programming, and in synthesis of logical control algorithms.To ensure unambiguous operation of the algorithms, the synthesized finite state automata must be deterministic. Within the approach to the synthesis of the mobile robot controls, for example, based on the theory of formal languages, there are problems concerning the construction of various finite automata, but such finite automata, as a rule, will not be deterministic. The algorithm of determinization can be applied to the finite automata, as specified, in various ways. The basic ideas of the algorithm of determinization can be most simply explained using the representations of a finite automaton in the form of a weighted directed graph.The paper deals with finite automata represented as weighted directed graphs, and discusses in detail the procedure for determining the finite automata represented in this way. Gives a detailed description of the algorithm for determining finite automata. A large number of examples illustrate a capability of the determinization algorithm.

  7. Statistical finite element analysis.

    Science.gov (United States)

    Khalaji, Iman; Rahemifar, Kaamran; Samani, Abbas

    2008-01-01

    A novel technique is introduced for tissue deformation and stress analysis. Compared to the conventional Finite Element method, this technique is orders of magnitude faster and yet still very accurate. The proposed technique uses preprocessed data obtained from FE analyses of a number of similar objects in a Statistical Shape Model framework as described below. This technique takes advantage of the fact that the body organs have limited variability, especially in terms of their geometry. As such, it is well suited for calculating tissue displacements of body organs. The proposed technique can be applied in many biomedical applications such as image guided surgery, or virtual reality environment development where tissue behavior is simulated for training purposes.

  8. Structural analysis with the finite element method linear statics

    CERN Document Server

    Oñate, Eugenio

    2013-01-01

    STRUCTURAL ANALYSIS WITH THE FINITE ELEMENT METHOD Linear Statics Volume 1 : The Basis and Solids Eugenio Oñate The two volumes of this book cover most of the theoretical and computational aspects of the linear static analysis of structures with the Finite Element Method (FEM). The content of the book is based on the lecture notes of a basic course on Structural Analysis with the FEM taught by the author at the Technical University of Catalonia (UPC) in Barcelona, Spain for the last 30 years. Volume1 presents the basis of the FEM for structural analysis and a detailed description of the finite element formulation for axially loaded bars, plane elasticity problems, axisymmetric solids and general three dimensional solids. Each chapter describes the background theory for each structural model considered, details of the finite element formulation and guidelines for the application to structural engineering problems. The book includes a chapter on miscellaneous topics such as treatment of inclined supports, elas...

  9. Axial anomaly at finite temperature

    International Nuclear Information System (INIS)

    Chaturvedi, S.; Gupte, Neelima; Srinivasan, V.

    1985-01-01

    The Jackiw-Bardeen-Adler anomaly for QED 4 and QED 2 are calculated at finite temperature. It is found that the anomaly is independent of temperature. Ishikawa's method [1984, Phys. Rev. Lett. vol. 53 1615] for calculating the quantised Hall effect is extended to finite temperature. (author)

  10. Solution of Finite Element Equations

    DEFF Research Database (Denmark)

    Krenk, Steen

    An important step in solving any problem by the finite element method is the solution of the global equations. Numerical solution of linear equations is a subject covered in most courses in numerical analysis. However, the equations encountered in most finite element applications have some special...... features that justify the development of specialized solution algorithms....

  11. Finite strain discrete dislocation plasticity

    NARCIS (Netherlands)

    Deshpande, VS; Needleman, A; Van der Giessen, E

    2003-01-01

    A framework for carrying out finite deformation discrete dislocation plasticity calculations is presented. The discrete dislocations are presumed to be adequately represented by the singular linear elastic fields so that the large deformations near dislocation cores are not modeled. The finite

  12. A Finite Element Analysis of a Carbon Fiber Composite Micro Air Vehicle Wing

    Science.gov (United States)

    2012-03-22

    Management Air Force Institute of Technology Air University Air Education and Training Command In Partial Fulfillment of the Requirements for the...using a developed MATLAB code that generated finite element input files to be solved using ABAQUS , a finite element program. The developed MATLAB code...program that is capable of generating an input file to be submitted to ABAQUS , a finite element model solver. This technique was used in order to

  13. Massively Parallel Finite Element Programming

    KAUST Repository

    Heister, Timo

    2010-01-01

    Today\\'s large finite element simulations require parallel algorithms to scale on clusters with thousands or tens of thousands of processor cores. We present data structures and algorithms to take advantage of the power of high performance computers in generic finite element codes. Existing generic finite element libraries often restrict the parallelization to parallel linear algebra routines. This is a limiting factor when solving on more than a few hundreds of cores. We describe routines for distributed storage of all major components coupled with efficient, scalable algorithms. We give an overview of our effort to enable the modern and generic finite element library deal.II to take advantage of the power of large clusters. In particular, we describe the construction of a distributed mesh and develop algorithms to fully parallelize the finite element calculation. Numerical results demonstrate good scalability. © 2010 Springer-Verlag.

  14. Finite element and finite difference methods in electromagnetic scattering

    CERN Document Server

    Morgan, MA

    2013-01-01

    This second volume in the Progress in Electromagnetic Research series examines recent advances in computational electromagnetics, with emphasis on scattering, as brought about by new formulations and algorithms which use finite element or finite difference techniques. Containing contributions by some of the world's leading experts, the papers thoroughly review and analyze this rapidly evolving area of computational electromagnetics. Covering topics ranging from the new finite-element based formulation for representing time-harmonic vector fields in 3-D inhomogeneous media using two coupled sca

  15. Support for major hypotheses in invasion biology is uneven and declining

    Directory of Open Access Journals (Sweden)

    Jonathan Jeschke

    2012-08-01

    Full Text Available Several major hypotheses have been proposed to explain and predict biological invasions, but the general applicability of these hypotheses is largely unknown, as most of them have not been evaluated using a standard approach across taxonomic groups and habitats. We offer such an evaluation for six selected leading hypotheses. Our global literature review reveals that those hypotheses that consider interactions of exotic invaders with their new environment (invasional meltdown, novel weapons, enemy release are better supported by empirical evidence than other hypotheses (biotic resistance, island susceptibility, tens rule. We also show that empirical support for the six hypotheses has declined over time, and that support differs among taxonomic groups and habitats. Our results have implications for basic and applied research, policy making, and invasive species management, as their effectiveness depends on sound hypotheses.

  16. Finite-temperature gauge theory from the transverse lattice.

    Science.gov (United States)

    Dalley, S; van de Sande, B

    2005-10-14

    Numerical computations are performed and analytic bounds are obtained on the excited spectrum of glueballs in SU(inifinity) gauge theory, by transverse lattice Hamiltonian methods. We find an exponential growth of the density of states, implying a finite critical (Hagedorn) temperature. It is argued that the Nambu-Goto string model lies in a different universality class.

  17. A generalization of the finiteness problem in local cohomology ...

    Indian Academy of Sciences (India)

    (Math. Sci.) Vol. 119, No. 2, April 2009, pp. 159–164. © Printed in India. A generalization of the finiteness problem in local cohomology modules. AMIR MAFI. Department of Mathematics, University of Kurdistan, P.O. Box 416, Sanandaj, Iran. Institute for Studies in Theoretical Physics and Mathematics, P.O. Box 19395-5746,.

  18. A note on conjugacy classes of finite groups

    Indian Academy of Sciences (India)

    Home; Journals; Proceedings – Mathematical Sciences; Volume 124; Issue 1. A Note on Conjugacy Classes of Finite Groups. Hemant Kalra Deepak Gumber. Volume 124 ... Author Affiliations. Hemant Kalra1 Deepak Gumber1. School of Mathematics and Computer Applications, Thapar University, Patiala 147 004, India ...

  19. A note on TI-subgroups of finite groups

    Indian Academy of Sciences (India)

    and LINNA PANG. Department of Mathematics, Guangxi Normal University, Guangxi, Guilin 541004,. People's Republic of China. ∗Author to whom correspondence should be addressed. E-mail: jklu@mailbox.gxnu.edu.cn. MS received 27 November 2010; revised 29 August 2011. Abstract. A subgroup H of a finite group G ...

  20. Finite discrete field theory

    International Nuclear Information System (INIS)

    Souza, Manoelito M. de

    1997-01-01

    We discuss the physical meaning and the geometric interpretation of implementation in classical field theories. The origin of infinities and other inconsistencies in field theories is traced to fields defined with support on the light cone; a finite and consistent field theory requires a light-cone generator as the field support. Then, we introduce a classical field theory with support on the light cone generators. It results on a description of discrete (point-like) interactions in terms of localized particle-like fields. We find the propagators of these particle-like fields and discuss their physical meaning, properties and consequences. They are conformally invariant, singularity-free, and describing a manifestly covariant (1 + 1)-dimensional dynamics in a (3 = 1) spacetime. Remarkably this conformal symmetry remains even for the propagation of a massive field in four spacetime dimensions. We apply this formalism to Classical electrodynamics and to the General Relativity Theory. The standard formalism with its distributed fields is retrieved in terms of spacetime average of the discrete field. Singularities are the by-products of the averaging process. This new formalism enlighten the meaning and the problem of field theory, and may allow a softer transition to a quantum theory. (author)

  1. quadratic spline finite element method

    Directory of Open Access Journals (Sweden)

    A. R. Bahadir

    2002-01-01

    Full Text Available The problem of heat transfer in a Positive Temperature Coefficient (PTC thermistor, which may form one element of an electric circuit, is solved numerically by a finite element method. The approach used is based on Galerkin finite element using quadratic splines as shape functions. The resulting system of ordinary differential equations is solved by the finite difference method. Comparison is made with numerical and analytical solutions and the accuracy of the computed solutions indicates that the method is well suited for the solution of the PTC thermistor problem.

  2. Finite Size Scaling of Perceptron

    OpenAIRE

    Korutcheva, Elka; Tonchev, N.

    2000-01-01

    We study the first-order transition in the model of a simple perceptron with continuous weights and large, bit finite value of the inputs. Making the analogy with the usual finite-size physical systems, we calculate the shift and the rounding exponents near the transition point. In the case of a general perceptron with larger variety of inputs, the analysis only gives bounds for the exponents.

  3. Incompleteness in the finite domain

    Czech Academy of Sciences Publication Activity Database

    Pudlák, Pavel

    2017-01-01

    Roč. 23, č. 4 (2017), s. 405-441 ISSN 1079-8986 EU Projects: European Commission(XE) 339691 - FEALORA Institutional support: RVO:67985840 Keywords : finite domain Subject RIV: BA - General Mathematics OBOR OECD: Pure mathematics Impact factor: 0.742, year: 2016 https://www.cambridge.org/core/journals/bulletin-of-symbolic-logic/article/incompleteness-in-the-finite-domain/D239B1761A73DCA534A4805A76D81C76

  4. Programming the finite element method

    CERN Document Server

    Smith, I M; Margetts, L

    2013-01-01

    Many students, engineers, scientists and researchers have benefited from the practical, programming-oriented style of the previous editions of Programming the Finite Element Method, learning how to develop computer programs to solve specific engineering problems using the finite element method. This new fifth edition offers timely revisions that include programs and subroutine libraries fully updated to Fortran 2003, which are freely available online, and provides updated material on advances in parallel computing, thermal stress analysis, plasticity return algorithms, convection boundary c

  5. Incompleteness in the finite domain

    Czech Academy of Sciences Publication Activity Database

    Pudlák, Pavel

    2017-01-01

    Roč. 23, č. 4 (2017), s. 405-441 ISSN 1079-8986 EU Projects: European Commission(XE) 339691 - FEALORA Institutional support: RVO:67985840 Keywords : finite domain Subject RIV: BA - General Mathematics OBOR OECD: Pure mathematics Impact factor: 0.742, year: 2016 https://www.cambridge.org/core/ journals /bulletin-of-symbolic-logic/article/incompleteness-in-the-finite-domain/D239B1761A73DCA534A4805A76D81C76

  6. Automatic Construction of Hypotheses for Linear Objects in Digital and Laser Scanning Images

    Directory of Open Access Journals (Sweden)

    Quintino Dalmolin

    2004-12-01

    Full Text Available This paper presents an automatic road hypotheses approach using digital image and laser scanning image combining various Digital Image Processing techniques. The semantic objects, in this work, are linear features, such as, roads and streets. The aim of this paper is extract automatically road hypotheses on image space and object space for use the information in automatic absolute orientation process. The results show that methodology is efficiency and the roads hypotheses are generate and validate.

  7. The Hydrological Open Air Laboratory (HOAL) in Petzenkirchen: a hypotheses driven observatory

    Science.gov (United States)

    Blöschl, G.; Blaschke, A. P.; Broer, M.; Bucher, C.; Carr, G.; Chen, X.; Eder, A.; Exner-Kittridge, M.; Farnleitner, A.; Flores-Orozco, A.; Haas, P.; Hogan, P.; Kazemi Amiri, A.; Oismüller, M.; Parajka, J.; Silasari, R.; Stadler, P.; Strauß, P.; Vreugdenhil, M.; Wagner, W.; Zessner, M.

    2015-07-01

    Hydrological observatories bear a lot of resemblance to the more traditional research catchment concept but tend to differ in providing more long term facilities that transcend the lifetime of individual projects, are more strongly geared towards performing interdisciplinary research, and are often designed as networks to assist in performing collaborative science. This paper illustrates how the experimental and monitoring setup of an observatory, the 66 ha Hydrological Open Air Laboratory (HOAL) in Petzenkirchen, Lower Austria, has been established in a way that allows meaningful hypothesis testing. The overarching science questions guided site selection, identifying dissertation topics and the base monitoring. The specific hypotheses guided the dedicated monitoring and sampling, individual experiments, and repeated experiments with controlled boundary conditions. The purpose of the HOAL is to advance the understanding of water related flow and transport processes involving sediments, nutrients and microbes in small catchments. The HOAL catchment is ideally suited for this purpose, because it features a range of different runoff generation processes (surface runoff, springs, tile drains, wetlands), the nutrient inputs are known, and it is convenient from a logistic point of view as all instruments can be connected to the power grid and a high speed glassfibre Local Area Network. The multitude of runoff generation mechanisms in the catchment provide a genuine laboratory where hypotheses of flow and transport can be tested, either by controlled experiments or by contrasting sub-regions of different characteristics. This diversity also ensures that the HOAL is representative of a range of catchments around the world and the specific process findings from the HOAL are applicable to a variety of agricultural catchment settings. The HOAL is operated jointly by the Vienna University of Technology and the Federal Agency for Water Management and takes advantage of the

  8. Quantum mechanics on spaces with finite fundamental group

    International Nuclear Information System (INIS)

    Giulini, D.

    1995-01-01

    We consider in general terms dynamical systems with finite-dimensional, non-simply connected configuration-spaces. The fundamental group is assumed to be finite. We analyze in full detail those ambiguities in the quantization procedure that arise from the non-simply connectedness of the classical configuration space. We define the quantum theory on the universal cover but restrict the algebra of observables O to the commutant of the algebra generated by deck-transformations. We apply standard superselection principles and construct the corresponding sectors. We emphasize the relevance of all sectors and not just the abelian ones. (orig.)

  9. Large scale structure statistics: Finite volume effects

    Science.gov (United States)

    Colombi, S.; Bouchet, F. R.; Schaeffer, R.

    1994-01-01

    We study finite volume effects on the count probability distribution function PN(l) and the averaged Q-body correlations Xi-barQ (2 less than or = Q less than or equal 5). These statistics are computed for cubic cells, of size l. We use as an example the case of the matter distribution of a cold dark matter (CDM) universe involving approximately 3 x 105 particles. The main effect of the finiteness of the sampled volume is to induce an abrupt cut-off on the function PN(l) at large N. This clear signature makes an analysis of the consequences easy, and one can envisage a correction procedure. As a matter of fact, we demonstrate how an unfair sample can strongly affect the estimates of the functions Xi-barQ for Q greater than or = 3 (and decrease the measured zero of the two-body correlation function). We propose a method to correct for this are fact, or at least to evaluate the corresponding errors. We show that the correlations are systematically underestimated by direct measurements. We find that, once corrected, the statistical properties of the CDM universe appear compatible with the scaling relation SQ identically equals Xi-bar2 exp Q-1 = constant with respect to scale, in the non-linear regime; it was not the case with direct measurments. However, we note a deviation from scaling at scales close to the correlation length. It is probably due to the transition between the highly non-linear regime and the weakly correlated regime, where the functions SQ also seem to present a plateau. We apply the same procedure to simulations with hot dark matter (HDM) and white noise initial conditions, with similar results. Our method thus provides the first accurate measurement of the normalized skewness, S3, and the normalized kurtosis, S4, for three typical models of large scale structure formation in an expanding universe.

  10. Evaluation of Inequality Constrained Hypotheses Using an Akaike-Type Information Criterion

    NARCIS (Netherlands)

    Altinisik, Y.

    2018-01-01

    The Akaike information criterion (AIC) is one of the best known information criteria that can be used to evaluate hypotheses containing only equality restrictions on model parameters. The GORIC is a generalization of the AIC that can be utilized to evaluate hypotheses containing equality and/or

  11. Black/White Differences in Adolescent Drug Use: A Test of Six Hypotheses

    Science.gov (United States)

    Rote, Sunshine M.; Taylor, John

    2014-01-01

    Six specific hypotheses have been developed to account for why Caucasians have higher rates of drug use compared to African-Americans. This article utilizes data from a South Florida-based community study of 893 young adults (1998-2002) to test these hypotheses. Specifically, Caucasians (1) initiate drug use at younger ages than African-Americans…

  12. Finite Element Modeling Techniques for Analysis of VIIP

    Science.gov (United States)

    Feola, Andrew J.; Raykin, J.; Gleason, R.; Mulugeta, Lealem; Myers, Jerry G.; Nelson, Emily S.; Samuels, Brian C.; Ethier, C. Ross

    2015-01-01

    Visual Impairment and Intracranial Pressure (VIIP) syndrome is a major health concern for long-duration space missions. Currently, it is thought that a cephalad fluid shift in microgravity causes elevated intracranial pressure (ICP) that is transmitted along the optic nerve sheath (ONS). We hypothesize that this in turn leads to alteration and remodeling of connective tissue in the posterior eye which impacts vision. Finite element (FE) analysis is a powerful tool for examining the effects of mechanical loads in complex geometries. Our goal is to build a FE analysis framework to understand the response of the lamina cribrosa and optic nerve head to elevations in ICP in VIIP.

  13. The wings before the bird: an evaluation of flapping-based locomotory hypotheses in bird antecedents

    Directory of Open Access Journals (Sweden)

    T. Alexander Dececchi

    2016-07-01

    Full Text Available Background: Powered flight is implicated as a major driver for the success of birds. Here we examine the effectiveness of three hypothesized pathways for the evolution of the flight stroke, the forelimb motion that powers aerial locomotion, in a terrestrial setting across a range of stem and basal avians: flap running, Wing Assisted Incline Running (WAIR, and wing-assisted leaping. Methods: Using biomechanical mathematical models based on known aerodynamic principals and in vivo experiments and ground truthed using extant avians we seek to test if an incipient flight stroke may have contributed sufficient force to permit flap running, WAIR, or leaping takeoff along the phylogenetic lineage from Coelurosauria to birds. Results: None of these behaviours were found to meet the biomechanical threshold requirements before Paraves. Neither was there a continuous trend of refinement for any of these biomechanical performances across phylogeny nor a signal of universal applicability near the origin of birds. None of these flap-based locomotory models appear to have been a major influence on pre-flight character acquisition such as pennaceous feathers, suggesting non-locomotory behaviours, and less stringent locomotory behaviours such as balancing and braking, played a role in the evolution of the maniraptoran wing and nascent flight stroke. We find no support for widespread prevalence of WAIR in non-avian theropods, but can’t reject its presence in large winged, small-bodied taxa like Microraptor and Archaeopteryx. Discussion: Using our first principles approach we find that “near flight” locomotor behaviors are most sensitive to wing area, and that non-locomotory related selection regimes likely expanded wing area well before WAIR and other such behaviors were possible in derived avians. These results suggest that investigations of the drivers for wing expansion and feather elongation in theropods need not be intrinsically linked to locomotory

  14. Solid finite elements through three decades

    OpenAIRE

    Venkatesh, DN; Shrinivasa, U

    1994-01-01

    conventionally, solid finite elements have been looked upon as just generalizations of two-dimensional finite elements. In this article we trace their development starting from the days of their inception. Keeping in tune with our perceptions on developing finite elements, without taking recourse to any extra variational techniques, we discuss a few of the techniques which have been applied to solid finite elements. Finally we critically examine our own work on formulating solid finite elemen...

  15. Finite canonical measure for nonsingular cosmologies

    International Nuclear Information System (INIS)

    Page, Don N.

    2011-01-01

    The total canonical (Liouville-Henneaux-Gibbons-Hawking-Stewart) measure is finite for completely nonsingular Friedmann-Lemaître-Robertson-Walker classical universes with a minimally coupled massive scalar field and a positive cosmological constant. For a cosmological constant very small in units of the square of the scalar field mass, most of the measure is for nearly de Sitter solutions with no inflation at a much more rapid rate. However, if one restricts to solutions in which the scalar field energy density is ever more than twice the equivalent energy density of the cosmological constant, then the number of e-folds of rapid inflation must be large, and the fraction of the measure is low in which the spatial curvature is comparable to the cosmological constant at the time when it is comparable to the energy density of the scalar field. The measure for such classical FLRWΛ-φ models with both a big bang and a big crunch is also finite. Only the solutions with a big bang that expand forever, or the time-reversed ones that contract from infinity to a big crunch, have infinite measure

  16. Finite and profinite quantum systems

    CERN Document Server

    Vourdas, Apostolos

    2017-01-01

    This monograph provides an introduction to finite quantum systems, a field at the interface between quantum information and number theory, with applications in quantum computation and condensed matter physics. The first major part of this monograph studies the so-called `qubits' and `qudits', systems with periodic finite lattice as position space. It also discusses the so-called mutually unbiased bases, which have applications in quantum information and quantum cryptography. Quantum logic and its applications to quantum gates is also studied. The second part studies finite quantum systems, where the position takes values in a Galois field. This combines quantum mechanics with Galois theory. The third part extends the discussion to quantum systems with variables in profinite groups, considering the limit where the dimension of the system becomes very large. It uses the concepts of inverse and direct limit and studies quantum mechanics on p-adic numbers. Applications of the formalism include quantum optics and ...

  17. Finite element methods for engineers

    CERN Document Server

    Fenner, Roger T

    2013-01-01

    This book is intended as a textbook providing a deliberately simple introduction to finite element methods in a way that should be readily understandable to engineers, both students and practising professionals. Only the very simplest elements are considered, mainly two dimensional three-noded “constant strain triangles”, with simple linear variation of the relevant variables. Chapters of the book deal with structural problems (beams), classification of a broad range of engineering into harmonic and biharmonic types, finite element analysis of harmonic problems, and finite element analysis of biharmonic problems (plane stress and plane strain). Full Fortran programs are listed and explained in detail, and a range of practical problems solved in the text. Despite being somewhat unfashionable for general programming purposes, the Fortran language remains very widely used in engineering. The programs listed, which were originally developed for use on mainframe computers, have been thoroughly updated for use ...

  18. Sound radiation from finite surfaces

    DEFF Research Database (Denmark)

    Brunskog, Jonas

    2013-01-01

    A method to account for the effect of finite size in acoustic power radiation problem of planar surfaces using spatial windowing is developed. Cremer and Heckl presents a very useful formula for the power radiating from a structure using the spatially Fourier transformed velocity, which combined...... with spatially windowing of a plane waves can be used to take into account the finite size. In the present paper, this is developed by means of a radiation impedance for finite surfaces, that is used instead of the radiation impedance for infinite surfaces. In this way, the spatial windowing is included...... in the radiation formula directly, and no pre-windowing is needed. Examples are given for the radiation efficiency, and the results are compared with results found in the literature....

  19. Liouville Cosmology at Zero and Finite Temperatures

    CERN Document Server

    Ellis, Jonathan Richard; Nanopoulos, Dimitri V; Westmuckett, M

    2006-01-01

    We discuss cosmology in the context of Liouville strings, characterized by a central-charge deficit Q^2, in which target time is identified with (the world-sheet zero mode of the) Liouville field: Q-Cosmology. We use a specific example of colliding brane worlds to illustrate the phase diagram of this cosmological framework. The collision provides the necessary initial cosmological instability, expressed as a departure from conformal invariance in the underlying string model. The brane motion provides a way of breaking target-space supersymmetry, and leads to various phases of the brane and bulk Universes. Specifically, we find a hot metastable phase for the bulk string Universe soon after the brane collision in which supersymmetry is broken, which we describe by means of a subcritical world-sheet sigma model dressed by a space-like Liouville field, representing finite temperature (Euclidean time). This phase is followed by an inflationary phase for the brane Universe, in which the bulk string excitations are ...

  20. Finite connectivity attractor neural networks

    International Nuclear Information System (INIS)

    Wemmenhove, B; Coolen, A C C

    2003-01-01

    We study a family of diluted attractor neural networks with a finite average number of (symmetric) connections per neuron. As in finite connectivity spin glasses, their equilibrium properties are described by order parameter functions, for which we derive an integral equation in replica symmetric approximation. A bifurcation analysis of this equation reveals the locations of the paramagnetic to recall and paramagnetic to spin-glass transition lines in the phase diagram. The line separating the retrieval phase from the spin-glass phase is calculated at zero temperature. All phase transitions are found to be continuous

  1. Finite connectivity attractor neural networks

    Science.gov (United States)

    Wemmenhove, B.; Coolen, A. C. C.

    2003-09-01

    We study a family of diluted attractor neural networks with a finite average number of (symmetric) connections per neuron. As in finite connectivity spin glasses, their equilibrium properties are described by order parameter functions, for which we derive an integral equation in replica symmetric approximation. A bifurcation analysis of this equation reveals the locations of the paramagnetic to recall and paramagnetic to spin-glass transition lines in the phase diagram. The line separating the retrieval phase from the spin-glass phase is calculated at zero temperature. All phase transitions are found to be continuous.

  2. Variational collocation on finite intervals

    International Nuclear Information System (INIS)

    Amore, Paolo; Cervantes, Mayra; Fernandez, Francisco M

    2007-01-01

    In this paper, we study a set of functions, defined on an interval of finite width, which are orthogonal and which reduce to the sinc functions when the appropriate limit is taken. We show that these functions can be used within a variational approach to obtain accurate results for a variety of problems. We have applied them to the interpolation of functions on finite domains and to the solution of the Schroedinger equation, and we have compared the performance of the present approach with others

  3. FINITE ELEMENT ANALYSIS OF STRUCTURES

    Directory of Open Access Journals (Sweden)

    PECINGINA OLIMPIA-MIOARA

    2015-05-01

    Full Text Available The application of finite element method is analytical when solutions can not be applied for deeper study analyzes static, dynamic or other types of requirements in different points of the structures .In practice it is necessary to know the behavior of the structure or certain parts components of the machine under the influence of certain factors static and dynamic . The application of finite element in the optimization of components leads to economic growth , to increase reliability and durability organs studied, thus the machine itself.

  4. Finite element analysis of degraded concrete structures - Workshop proceedings

    International Nuclear Information System (INIS)

    1999-09-01

    This workshop is related to the finite element analysis of degraded concrete structures. It is composed of three sessions. The first session (which title is: the use of finite element analysis in safety assessments) comprises six papers which titles are: Historical Development of Concrete Finite Element Modeling for Safety Evaluation of Accident-Challenged and Aging Concrete Structures; Experience with Finite Element Methods for Safety Assessments in Switzerland; Stress State Analysis of the Ignalina NPP Confinement System; Prestressed Containment: Behaviour when Concrete Cracking is Modelled; Application of FEA for Design and Support of NPP Containment in Russia; Verification Problems of Nuclear Installations Safety Software of Strength Analysis (NISS SA). The second session (title: concrete containment structures under accident loads) comprises seven papers which titles are: Two Application Examples of Concrete Containment Structures under Accident Load Conditions Using Finite Element Analysis; What Kind of Prediction for Leak rates for Nuclear Power Plant Containments in Accidental Conditions; Influence of Different Hypotheses Used in Numerical Models for Concrete At Elevated Temperatures on the Predicted Behaviour of NPP Core Catchers Under Severe Accident Conditions; Observations on the Constitutive Modeling of Concrete Under Multi-Axial States at Elevated Temperatures; Analyses of a Reinforced Concrete Containment with Liner Corrosion Damage; Program of Containment Concrete Control During Operation for the Temelin Nuclear Power Plant; Static Limit Load of a Deteriorated Hyperbolic Cooling Tower. The third session (concrete structures under extreme environmental load) comprised five papers which titles are: Shear Transfer Mechanism of RC Plates After Cracking; Seismic Back Calculation of an Auxiliary Building of the Nuclear Power Plant Muehleberg, Switzerland; Seismic Behaviour of Slightly Reinforced Shear Wall Structures; FE Analysis of Degraded Concrete

  5. Lattice QCD at finite temperature

    International Nuclear Information System (INIS)

    DeTar, C.

    1988-01-01

    Recent progress in the numerical simulation of QCD at finite temperature is reviewed. Eight topics are treated briefly: (1) T c scaling, (2) Equation of state, (3) Baryon susceptibility, (4) The QCD Phase Diagram, (5) J/Ψ Binding in the Plasma, (6) The Screening Spectrum of the Plasma, (7) Gauge Symmetry Breaking at High T, (8) Progress in Computing Power. (author)

  6. Linguistics, Logic, and Finite Trees

    NARCIS (Netherlands)

    Blackburn, P.; Meyer-Viol, W.

    1993-01-01

    A modal logic is developed to deal with finite ordered binary trees as they are used in (computational) linguistics. A modal language is introduced with operators for the 'mother of', 'first daughter of' and 'second daughter of' relations together with their transitive reflexive closures.

  7. On symmetric pyramidal finite elements

    Czech Academy of Sciences Publication Activity Database

    Liu, L.; Davies, K. B.; Yuan, K.; Křížek, Michal

    2004-01-01

    Roč. 11, 1-2 (2004), s. 213-227 ISSN 1492-8760 R&D Projects: GA AV ČR IAA1019201 Institutional research plan: CEZ:AV0Z1019905 Keywords : mesh generation * finite element method * composite elements Subject RIV: BA - General Mathematics Impact factor: 0.108, year: 2004

  8. Ward identities at finite temperature

    International Nuclear Information System (INIS)

    DOlivo, J.C.; Torres, M.; Tututi, E.

    1996-01-01

    The Ward identities for QED at finite temperature are derived using the functional real-time formalism. They are verified by an explicit one-loop calculation. An effective causal vertex is constructed which satisfy the Ward identity with the associated retarded self-energy. copyright 1996 American Institute of Physics

  9. New Observations of Crustal Plateau Surface Histories, Venus: Implications for Crustal Plateau Hypotheses

    Science.gov (United States)

    Hansen, V. L.

    2005-03-01

    Geohistories documented for four crustal plateaus surface presents challenges to both downwelling and plume hypotheses of plateau formation, and lead to a third hypothesis, plateau formation involving crystallization of a huge lava pond.

  10. Corrigendum to: Bayesian evaluation of informative hypotheses in SEM using Mplus

    NARCIS (Netherlands)

    van de Schoot, R.; Verhoeven, Marjolein; Hoijtink, H.

    2014-01-01

    This paper corrects: van de Schoot, R., Verhoeven, M., & Hoijtink, H. (2013). Bayesian evaluation ofinformative hypotheses in SEM using Mplus: A black bear story. EuropeanJournal of Developmental Psychology, 10, 81 –98.

  11. A criterion for testing hypotheses about the covariance function of a stationary Gaussian stochastic process

    OpenAIRE

    Kozachenko, Yuriy; Troshki, Viktor

    2015-01-01

    We consider a measurable stationary Gaussian stochastic process. A criterion for testing hypotheses about the covariance function of such a process using estimates for its norm in the space $L_p(\\mathbb {T}),\\,p\\geq1$, is constructed.

  12. Testing contingency hypotheses in budgetary research: An evaluation of the use of moderated regression analysis

    NARCIS (Netherlands)

    Hartmann, Frank G.H.; Moers, Frank

    1999-01-01

    In the contingency literature on the behavioral and organizational effects of budgeting, use of the Moderated Regression Analysis (MRA) technique is prevalent. This technique is used to test contingency hypotheses that predict interaction effects between budgetary and contextual variables. This

  13. Comparison for aphasic and control subjects of eye movements hypothesized in neurolinguistic programming.

    Science.gov (United States)

    Dooley, K O; Farmer, A

    1988-08-01

    Neurolinguistic programming's hypothesized eye movements were measured independently using videotapes of 10 nonfluent aphasic and 10 control subjects matched for age and sex. Chi-squared analysis indicated that eye-position responses were significantly different for the groups. Although earlier research has not supported the hypothesized eye positions for normal subjects, the present findings support the contention that eye-position responses may differ between neurologically normal and aphasic individuals.

  14. Abortion Attitudes Among University Students in India.

    Science.gov (United States)

    Bardis, Panos D.

    This report hypothesized that Indian university students approve of abortion, that religiosity neutralizes the influence of education in abortion attitudes, and that Indian students are more liberal in their attitudes on abortion than American Catholic students. To test these hypotheses, the author collected data from 150 students from two…

  15. Integrable finite-dimensional systems related to Lie algebras

    International Nuclear Information System (INIS)

    Olshanetsky, M.A.; Perelomov, A.M.

    1979-01-01

    Some solvable finite-dimensional classical and quantum systems related to the Lie algebras are considered. The dynamics of these systems is closely related to free motion on symmetric spaces. In specific cases the systems considered describe the one-dimensional n-body problem recently considered by many authors. The review represents from general and universal point of view the results obtained during the last few years. Besides, it contains some results both of physical and mathematical type

  16. Study design, objectives, hypotheses, main findings, health consequences for the population exposed, rationale of future research

    Energy Technology Data Exchange (ETDEWEB)

    Trnovec, T.; Kocan, A. [Slovak Medical Univ., Bratislava (Slovakia); Bencko, V. [Charles Univ., Prague (Czech Republic); Langer, P. [Institute of Experimental Endocrinology SAS, Bratislava (Slovakia); Berg, M. van den [Rijksuniversiteit Utrecht (Netherlands); Bergman, A. [Stockholm Univ. (Sweden); Hustak, M. [Air Force Military Hospital, Kosics (Slovakia)

    2004-09-15

    In Slovakia, the Chemko Chemical Company, based in Strazske, in the Michalovce district, produced PCBs between 1959 and 1984, in the amount of more than 21,000 tons of commercial mixtures (Delor 103, 104, 105, 106, Delotherm DK and DH, Hydelor 137). PCBs were used for similar industrial purposes as in the west. Improper disposal from the Chemko plant via release of effluent directly into the Laborec River resulted in long-term contamination of sediment. As a result eastern Slovakia, the Michalovce district in particular, is recognized as one of the areas all over the world most heavily polluted with PCBs. Historical studies show that blood and adipose PCB levels were higher in Czechoslovakia than elsewhere in the 1970's and 1980's. Current data indicate that persons who eat locally raised food - pork, beef, poultry, eggs - in this district have elevated serum concentrations of PCBs. Environmental exposure to organochlorines in the Michalovce district indicate association with higher rates of certain cancers, but an inverse association with risk of breast cancer. An increased prevalence of thyroid disorders in the polluted area was also reported. This ''experimental setting in nature'' has attracted international scientific teams and two projects in the area are ongoing: Evaluating Human Health Risk from Low-dose and Long-term PCB Exposure, 5{sup th} FP Project QLK4-2000-00488, 2001- 2004; PCBRISK (http://www.pcbrisk.sk/) and Early Childhood Development and PCB Exposures in Slovakia, NCI/NIH, R01-CA96525 University of California, Davis, USA. This paper is serving as an introduction to papers of a session reporting on various health outcomes associated with PCB exposure. The objectives of the PCBRISK project were targeted at an evaluation of the human health risks of low-dose and long-term exposure to a group of persistent organochlorine pollutants, including polychlorinated biphenyls (PCBs) and their metabolites, organochlorine

  17. Testing hypotheses for the use of Icelandic volcanic ashes as low cost, natural fertilizers

    Science.gov (United States)

    Seward, W.; Edwards, B.

    2012-04-01

    Andisols are soils derived from tephra/volcanic bedrock and are generally considered to be fertile for plant growth (cf. University of Hawaii at Manoa, CTAHR). However, few studies have been published examining the immediate effects of the addition of volcanic ash to soils immediately after an eruption. Our research is motivated by unpublished accounts from Icelandic farmers that the growing season following the 2010 Eyjafjallajökull eruption ended with unusually high yields in areas that were covered by ash from the eruption early in the spring. To test the hypothesis that addition of volcanic ash to soil would have no immediate effect on plant growth, we conducted a ~6 week growth experiment in at controlled environment at the Dickinson College Farm. The experiment used relatively fast growing grain seeds as a test crop, controlled watering, known quantities of peat as an organic base, and the following general experimental design: peat was mixed in known but systematically differing proportions with 1) commercial quartz sand, 2) basaltic ash from the 2004 Grimsvötn eruption, and 3) trachyandesite ash from the 2010 Eyjafjallajökull eruption. For all experiments, the seeds growing in the simulated soil created with the two different composition volcanic ash had higher germination rates, higher growth rates, and produced plants that were healthier in appearance than the soil made from peat mixed with quartz sand. Some differences were also noted between the germination and grow rates between the basaltic and trachyandesitic ash experiments as well. Working hypotheses to explain these results include (1) shard shapes and vesicles from volcanic ash provide better water retention than quartz, allowing water to be stored longer and increasing average soil moisture, and (2) chemical nutrients from the ash facilitate germination and growth of plants. Documenting the potential benefits of fresh volcanic ash as a fertilizer is important as use of fresh ash fertlizer

  18. Induced Chern-Simons term in lattice QCD at finite temperature

    International Nuclear Information System (INIS)

    Borisenko, O.A.; Petrov, V.K.; Zinov'ev, G.M.

    1992-01-01

    The general conditions when the Chern-Simons action could arise (in continuum limit) as non universal contribution of fermionic determinant of finite-temperature lattice QCD are formulated. The dependence of this action coefficient on non universal parameters (a chemical potential, vacuum features, etc.) is investigated in detail. Special attention is paid to the role of possible 0 >-condensate existence. 42 refs. (author)

  19. Introduction to finite temperature and finite density QCD

    International Nuclear Information System (INIS)

    Kitazawa, Masakiyo

    2014-01-01

    It has been pointed out that QCD (Quantum Chromodynamics) in the circumstances of medium at finite temperature and density shows numbers of phenomena similar to the characteristics of solid state physics, e.g. phase transitions. In the past ten years, the very high temperature and density matter came to be observed experimentally at the heavy ion collisions. At the same time, the numerical QCD analysis at finite temperature and density attained quantitative level analysis possible owing to the remarkable progress of computers. In this summer school lecture, it has been set out to give not only the recent results, but also the spontaneous breaking of the chiral symmetry, the fundamental theory of finite temperature and further expositions as in the following four sections. The first section is titled as 'Introduction to Finite Temperature and Density QCD' with subsections of 1.1 standard model and QCD, 1.2 phase transition and phase structure of QCD, 1.3 lattice QCD and thermodynamic quantity, 1.4 heavy ion collision experiments, and 1.5 neutron stars. The second one is 'Equilibrium State' with subsections of 2.1 chiral symmetry, 2.2 vacuum state: BCS theory, 2.3 NJL (Nambu-Jona-Lasinio) model, and 2.4 color superconductivity. The third one is 'Static fluctuations' with subsections of 3.1 fluctuations, 3.2 moment and cumulant, 3.3 increase of fluctuations at critical points, 3.4 analysis of fluctuations by lattice QCD and Taylor expansion, and 3.5 experimental exploration of QCD phase structure. The fourth one is 'Dynamical Structure' with 4.1 linear response theory, 4.2 spectral functions, 4.3 Matsubara function, and 4.4 analyses of dynamical structure by lattice QCD. (S. Funahashi)

  20. An introduction to the mathematical theory of finite elements

    CERN Document Server

    Oden, J T

    2011-01-01

    This introduction to the theory of Sobolev spaces and Hilbert space methods in partial differential equations is geared toward readers of modest mathematical backgrounds. It offers coherent, accessible demonstrations of the use of these techniques in developing the foundations of the theory of finite element approximations.J. T. Oden is Director of the Institute for Computational Engineering & Sciences (ICES) at the University of Texas at Austin, and J. N. Reddy is a Professor of Engineering at Texas A&M University. They developed this essentially self-contained text from their seminars and co

  1. An eternal universe

    International Nuclear Information System (INIS)

    Novello, M.; Heintzmann, H.

    1983-01-01

    A new generalized solution of Maxwell-Einstein equations (which are non-minimally coupled) which leads to some fascinating aspects of the Universe is presented. The Cosmos has no singularity due to the coupling of longitudinal electromagnetism with space-time. It contains the Milne-Schucking cosmos as a limiting case. This model contains a free parameter (the longitudinal electromagnetic field) which allows one to fix the density of highest compression of the Cosmos. Alternativelly the parameter allows one to adjust our cosmos to the presently observed Hubble constant and the deceleration parameter. The model seems to be a viable candidate for our real cosmos as it allows one to extend the time scale of the Universe to arbitrarily large values i.e., it is able to provide the necessary time scale for the origin of life. It is speculated that the entropy is finite but intelligence in the Universe may be infinite. (Author) [pt

  2. University Internationalization and University Autonomy

    DEFF Research Database (Denmark)

    Turcan, Romeo V.; Gulieva, Valeria

    2016-01-01

    Turcan and Gulieva deepen our theoretical understanding of the process of university internationalisation by exploring the relationship between university internationalisation and university autonomy. They conjecture that the process of university internationalisation and its sustainability are d...

  3. Finite Cosmology and a CMB Cold Spot

    Energy Technology Data Exchange (ETDEWEB)

    Adler, R.J.; /Stanford U., HEPL; Bjorken, J.D.; /SLAC; Overduin, J.M.; /Stanford U., HEPL

    2006-03-20

    The standard cosmological model posits a spatially flat universe of infinite extent. However, no observation, even in principle, could verify that the matter extends to infinity. In this work we model the universe as a finite spherical ball of dust and dark energy, and obtain a lower limit estimate of its mass and present size: the mass is at least 5 x 10{sup 23}M{sub {circle_dot}} and the present radius is at least 50 Gly. If we are not too far from the dust-ball edge we might expect to see a cold spot in the cosmic microwave background, and there might be suppression of the low multipoles in the angular power spectrum. Thus the model may be testable, at least in principle. We also obtain and discuss the geometry exterior to the dust ball; it is Schwarzschild-de Sitter with a naked singularity, and provides an interesting picture of cosmogenesis. Finally we briefly sketch how radiation and inflation eras may be incorporated into the model.

  4. Geodesic motion and confinement in Goedel's universe

    International Nuclear Information System (INIS)

    Novello, M.; Soares, I.D.; Tiomno, J.

    1982-01-01

    A complete study of geodesic motion in Goedel's universe, using the method of the Effective Potential is presented. It then emerges a clear physical picture of free motion and its stability in this universe. Geodesics of a large class have finite intervals in which the particle moves back in time (dt/ds [pt

  5. Finite elements methods in mechanics

    CERN Document Server

    Eslami, M Reza

    2014-01-01

    This book covers all basic areas of mechanical engineering, such as fluid mechanics, heat conduction, beams, and elasticity with detailed derivations for the mass, stiffness, and force matrices. It is especially designed to give physical feeling to the reader for finite element approximation by the introduction of finite elements to the elevation of elastic membrane. A detailed treatment of computer methods with numerical examples are provided. In the fluid mechanics chapter, the conventional and vorticity transport formulations for viscous incompressible fluid flow with discussion on the method of solution are presented. The variational and Galerkin formulations of the heat conduction, beams, and elasticity problems are also discussed in detail. Three computer codes are provided to solve the elastic membrane problem. One of them solves the Poisson’s equation. The second computer program handles the two dimensional elasticity problems, and the third one presents the three dimensional transient heat conducti...

  6. Automation of finite element methods

    CERN Document Server

    Korelc, Jože

    2016-01-01

    New finite elements are needed as well in research as in industry environments for the development of virtual prediction techniques. The design and implementation of novel finite elements for specific purposes is a tedious and time consuming task, especially for nonlinear formulations. The automation of this process can help to speed up this process considerably since the generation of the final computer code can be accelerated by order of several magnitudes. This book provides the reader with the required knowledge needed to employ modern automatic tools like AceGen within solid mechanics in a successful way. It covers the range from the theoretical background, algorithmic treatments to many different applications. The book is written for advanced students in the engineering field and for researchers in educational and industrial environments.

  7. Factorization properties of finite spaces

    Energy Technology Data Exchange (ETDEWEB)

    Simkhovich, B; Mann, A; Zak, J, E-mail: boriskas@tx.technion.ac.i, E-mail: ady@physics.technion.ac.i, E-mail: zak@physics.technion.ac.i [Department of Physics, Technion-Israel Institute of Technology, Haifa 32000 (Israel)

    2010-01-29

    In 1960 Schwinger (J Schwinger 1960 Proc. Natl Acad. Sci. 46 570-9) proposed the algorithm for factorization of unitary operators in the finite M-dimensional Hilbert space according to a coprime decomposition of M. Using a special permutation operator A we generalize the Schwinger factorization to every decomposition of M. We obtain the factorized pairs of unitary operators and show that they obey the same commutation relations as Schwinger's. We apply the new factorization to two problems. First, we show how to generate two kq-like mutually unbiased bases for any composite dimension. Then, using a Harper-like Hamiltonian model in the finite dimension M = M{sub 1}M{sub 2}, we show how to design a physical system with M{sub 1} energy levels, each having degeneracy M{sub 2}.

  8. Representation theory of finite monoids

    CERN Document Server

    Steinberg, Benjamin

    2016-01-01

    This first text on the subject provides a comprehensive introduction to the representation theory of finite monoids. Carefully worked examples and exercises provide the bells and whistles for graduate accessibility, bringing a broad range of advanced readers to the forefront of research in the area. Highlights of the text include applications to probability theory, symbolic dynamics, and automata theory. Comfort with module theory, a familiarity with ordinary group representation theory, and the basics of Wedderburn theory, are prerequisites for advanced graduate level study. Researchers in algebra, algebraic combinatorics, automata theory, and probability theory, will find this text enriching with its thorough presentation of applications of the theory to these fields. Prior knowledge of semigroup theory is not expected for the diverse readership that may benefit from this exposition. The approach taken in this book is highly module-theoretic and follows the modern flavor of the theory of finite dimensional ...

  9. Hidden decay of impact after education for self-management of chronic illnesses: hypotheses.

    Science.gov (United States)

    Park, M J; Green, Joseph; Ishikawa, Hirono; Kiuchi, Takahiro

    2013-03-01

    People with chronic illnesses can benefit from self-management education. However, those benefits are said to decay over time (there is some evidence that this 'decay of impact' does occur), and the reinforcements used to prevent that decay appear to be ineffective. We hypothesize that the reinforcements appear to be ineffective because decay of impact occurs only in a subgroup of these programs' participants, so any benefits of reinforcements in that subgroup are concealed by whole-group summary statistics. We also hypothesize that reinforcements can benefit those who need them - those who would otherwise have decay. One approach to testing these hypotheses requires analysis of individual-level data, which is uncommon in this field. Some useful data could come from studies that have already been completed, but the strongest evidence will require prospectively designed tests in future trials. If the hypotheses are false, then time and resources spent on reinforcements can be saved or redirected. If the hypotheses are true, then reinforcements can be implemented with less waste and they can be made more effective. These programs can also be improved to better fit their users' needs, and there can be a new basis for evaluating the programs' effectiveness.

  10. Finite Metric Spaces of Strictly Negative Type

    DEFF Research Database (Denmark)

    Hjorth, Poul; Lisonek, P.; Markvorsen, Steen

    1998-01-01

    We prove that, if a finite metric space is of strictly negative type, then its transfinite diameter is uniquely realized by the infinite extender (load vector). Finite metric spaces that have this property include all spaces on two, three, or four points, all trees, and all finite subspaces of Eu...

  11. The construction of finite solvable groups revisited

    OpenAIRE

    Eick, Bettina; Horn, Max

    2013-01-01

    We describe a new approach towards the systematic construction of finite groups up to isomorphism. This approach yields a practical algorithm for the construction of finite solvable groups up to isomorphism. We report on a GAP implementation of this method for finite solvable groups and exhibit some sample applications.

  12. Proving Finite Satisfiability of Deductive Databases

    OpenAIRE

    Bry, François; Manthey, Rainer

    1987-01-01

    It is shown how certain refutation methods can be extended into semi-decision procedures that are complete for both unsatisfiability and finite satisfiability. The proposed extension is justified by a new characterization of finite satisfiability. This research was motivated by a database design problem: Deduction rules and integrity constraints in definite databases have to be finitely satisfiable

  13. Characterization of finite spaces having dispersion points

    International Nuclear Information System (INIS)

    Al-Bsoul, A. T

    1997-01-01

    In this paper we shall characterize the finite spaces having dispersion points. Also, we prove that the dispersion point of a finite space with a dispersion points fixed under all non constant continuous functions which answers the question raised by J. C obb and W. Voxman in 1980 affirmatively for finite space. Some open problems are given. (author). 16 refs

  14. Quantum Chromodynamic at finite temperature

    International Nuclear Information System (INIS)

    Magalhaes, N.S.

    1987-01-01

    A formal expression to the Gibbs free energy of topological defects of quantum chromodynamics (QCD)by using the semiclassical approach in the context of field theory at finite temperature and in the high temperature limit is determined. This expression is used to calculate the free energy of magnetic monopoles. Applying the obtained results to a method in which the free energy of topological defects of a theory may indicate its different phases, its searched for informations about phases of QCD. (author) [pt

  15. Spinor pregeometry at finite temperature

    International Nuclear Information System (INIS)

    Yoshimoto, Seiji.

    1985-10-01

    We derive the effective action for gravity at finite temperature in spinor pregeometry. The temperature-dependent effective potential for the vierbein which is parametrized as e sub(kμ) = b.diag(1, xi, xi, xi) has the minimum at b = 0 for fixed xi, and behaves as -xi 3 for fixed b. These results indicate that the system of fundamental matters in spinor pregeometry cannot be in equilibrium. (author)

  16. Strange matter at finite temperatures

    International Nuclear Information System (INIS)

    Reinhardt, H.; Dang, B.V.

    1987-12-01

    The properties of strange quark matter at finite temperatures and in equilibrium with respect to weak interaction are explored on the basis of the MIT bag model picture of QCD. Furthermore, to determine the stability of strange quark matter analogous investigations are also performed for nuclear matter within Walecka's model field theory. It is found that strange quark matter can be stable at zero external pressure only for temperatures below 20 MeV. (orig.)

  17. Finite mathematics models and applications

    CERN Document Server

    Morris, Carla C

    2015-01-01

    Features step-by-step examples based on actual data and connects fundamental mathematical modeling skills and decision making concepts to everyday applicability Featuring key linear programming, matrix, and probability concepts, Finite Mathematics: Models and Applications emphasizes cross-disciplinary applications that relate mathematics to everyday life. The book provides a unique combination of practical mathematical applications to illustrate the wide use of mathematics in fields ranging from business, economics, finance, management, operations research, and the life and social sciences.

  18. Propagator for finite range potentials

    International Nuclear Information System (INIS)

    Cacciari, Ilaria; Moretti, Paolo

    2006-01-01

    The Schroedinger equation in integral form is applied to the one-dimensional scattering problem in the case of a general finite range, nonsingular potential. A simple expression for the Laplace transform of the transmission propagator is obtained in terms of the associated Fredholm determinant, by means of matrix methods; the particular form of the kernel and the peculiar aspects of the transmission problem play an important role. The application to an array of delta potentials is shown

  19. Perturbative QCD at finite temperature

    International Nuclear Information System (INIS)

    Altherr, T.

    1989-03-01

    We discuss an application of finite temperature QCD to lepton-pair production in a quark-gluon plasma. The perturbative calculation is performed within the realtime formalism. After cancellation of infrared and mass singularities, the corrections at O (α s ) are found to be very small in the region where the mass of the Drell-Yan pair is much larger than the temperature of the plasma. Interesting effects, however, appear at the annihilation threshold of the thermalized quarks

  20. Dreaming and waking experiences in schizophrenia: how should the (dis)continuity hypotheses be approached empirically?

    Science.gov (United States)

    Noreika, Valdas

    2011-06-01

    A number of differences between the dreams of schizophrenia patients and those of healthy participants have been linked to changes in waking life that schizophrenia may cause. This way, the "continuity hypothesis" has become a standard way to relate dreaming and waking experiences in schizophrenia. Nevertheless, some of the findings in dream literature are not compatible with the continuity hypothesis and suggest some other ways how dream content and waking experiences could interact. Conceptually, the continuity hypothesis could be sharpened into the "waking-to-dreaming" and the "dreaming-to-waking" hypotheses, whereas a less explored type of "discontinuity" could embrace the "compensated waking" and the "compensated dreaming" hypotheses. A careful consideration and empirical testing of each of those hypotheses may reveal a multiplicity of the ways how dreaming and waking life interact in schizophrenia. Copyright © 2010 Elsevier Inc. All rights reserved.

  1. Causal null hypotheses of sustained treatment strategies: What can be tested with an instrumental variable?

    Science.gov (United States)

    Swanson, Sonja A; Labrecque, Jeremy; Hernán, Miguel A

    2018-05-02

    Sometimes instrumental variable methods are used to test whether a causal effect is null rather than to estimate the magnitude of a causal effect. However, when instrumental variable methods are applied to time-varying exposures, as in many Mendelian randomization studies, it is unclear what causal null hypothesis is tested. Here, we consider different versions of causal null hypotheses for time-varying exposures, show that the instrumental variable conditions alone are insufficient to test some of them, and describe additional assumptions that can be made to test a wider range of causal null hypotheses, including both sharp and average causal null hypotheses. Implications for interpretation and reporting of instrumental variable results are discussed.

  2. R and D appropriability, opportunity, and market structure: new evidence on some Schumpeterian hypotheses

    Energy Technology Data Exchange (ETDEWEB)

    Levin, R.C.; Cohen, W.M.; Mowery, D.C.

    1985-05-01

    One of the largest bodies of literature in the field of industrial organization is devoted to the interpretation and testing of several hypotheses advanced by Joseph Schumpeter (1950) concerning innovation and industrial market structure. One set of hypotheses focuses on the role of firm size as a determinant of R and D spending and the rate of technological advance. Another set focuses on the effect of market concentration on R and D and technological advance. In this paper, the latter set of hypotheses is reexamined at the industry level, using new data on R and D appropriability and technological opportunity collected by Leven et al. (1984) in a survey of R and D executives in 130 industries. 6 references.

  3. Theory of critical phenomena in finite-size systems scaling and quantum effects

    CERN Document Server

    Brankov, Jordan G; Tonchev, Nicholai S

    2000-01-01

    The aim of this book is to familiarise the reader with the rich collection of ideas, methods and results available in the theory of critical phenomena in systems with confined geometry. The existence of universal features of the finite-size effects arising due to highly correlated classical or quantum fluctuations is explained by the finite-size scaling theory. This theory (1) offers an interpretation of experimental results on finite-size effects in real systems; (2) gives the most reliable tool for extrapolation to the thermodynamic limit of data obtained by computer simulations; (3) reveals

  4. Deconfinement phase transition and finite-size scaling in SU(2) lattice gauge theory

    International Nuclear Information System (INIS)

    Mogilevskij, O.A.

    1988-01-01

    Calculation technique for deconfinement phase transition parameters based on application of finite-size scaling theory is suggested. The essence of the technique lies in plotting of universal scaling function on the basis of numerical data obtained at different-size final lattices and discrimination of phase transition parameters for infinite lattice system. Finite-size scaling technique was developed as applied to spin system theory. β critical index for Polyakov loop and SU(2) deconfinement temperature of lattice gauge theory are calculated on the basis of finite-size scaling technique. The obtained value agrees with critical index of magnetization in Ising three-dimensional model

  5. The scientific role of hypotheses and the reasoning of college students in physics problem solving

    Directory of Open Access Journals (Sweden)

    Jenaro Guisasola

    2003-08-01

    Full Text Available This paper attempts to explore how freshmen college students in engineering state hypoteses to build their own problem solving structure when dealing with physics problems. From the constructivist perspective of the teaching and learning process hypotheses stating plays a fundamental role to check the coherence of students' ideas against the theoretical framework. The main instruments to accede to students' reasoning were their written solutions to four problematic situations in which they were asked to state hypotheses. The protocols were analysed according to a standard methodology. In this paper two of such problematic situations and the corresponding cathegorization schemes are presented in addition to reseach findings and conclusions.

  6. Declining forest productivity in aging forest stands: a modeling analysis of alternative hypotheses

    Energy Technology Data Exchange (ETDEWEB)

    Murty, D.; McMurtrie, R. E. [New South Wales Univ., Sydney, NSW (Australia); Ryan, M. G. [Forest Service, Fort Collins, CO (United States). Rocky Mountain Forest and Range Experiment Station

    1996-01-01

    Various hypotheses regarding the decline in forest net primary productivity (NPP) with age in closed-canopy stands were evaluated by graphical analysis using the G`DAY model. Results indicated that the interaction between decline in stomatal conductance, hence photosynthetic efficiency and decline in soil nutrient availability, provided the most plausible answer to reduced productivity, although the relative importance of these two explanations varied according to certain key model assumptions. Increased sapwood respiration, one of the hypotheses tested, was found to have only a minor effect on the decline of forest productivity. 60 refs., 6 figs.

  7. Subshifts of finite type and self-similar sets

    Science.gov (United States)

    Jiang, Kan; Dajani, Karma

    2017-02-01

    Let K\\subset {R} be a self-similar set generated by some iterated function system. In this paper we prove, under some assumptions, that K can be identified with a subshift of finite type. With this identification, we can calculate the Hausdorff dimension of K as well as the set of elements in K with unique codings using the machinery of Mauldin and Williams (1988 Trans. Am. Math. Soc. 309 811-29). We give three different applications of our main result. Firstly, we calculate the Hausdorff dimension of the set of points of K with multiple codings. Secondly, in the setting of β-expansions, when the set of all the unique codings is not a subshift of finite type, we can calculate in some cases the Hausdorff dimension of the univoque set. Motivated by this application, we prove that the set of all the unique codings is a subshift of finite type if and only if it is a sofic shift. This equivalent condition was not mentioned by de Vries and Komornik (2009 Adv. Math. 221 390-427, theorem 1.8). Thirdly, for the doubling map with asymmetrical holes, we give a sufficient condition such that the survivor set can be identified with a subshift of finite type. The third application partially answers a problem posed by Alcaraz Barrera (2014 PhD Thesis University of Manchester).

  8. Extension of p-local finite groups

    OpenAIRE

    Broto, Carles; Castellana, Natalia; Grodal, Jesper; Levi, Ran; Oliver, Bob

    2005-01-01

    A p-local finite group consists of a finite p-group S, together with a pair of categories which encode ``conjugacy'' relations among subgroups of S, and which are modelled on the fusion in a Sylow p-subgroup of a finite group. It contains enough information to define a classifying space which has many of the same properties as p-completed classifying spaces of finite groups. In this paper, we study and classify extensions of p-local finite groups, and also compute the fundamental group of the...

  9. Finite Metric Spaces of Strictly negative Type

    DEFF Research Database (Denmark)

    Hjorth, Poul G.

    If a finite metric space is of strictly negative type then its transfinite diameter is uniquely realized by an infinite extent (“load vector''). Finite metric spaces that have this property include all trees, and all finite subspaces of Euclidean and Hyperbolic spaces. We prove that if the distance...... matrix of a finite metric space is both hypermetric and regular, then it is of strictly negative type. We show that the strictly negative type finite subspaces of spheres are precisely those which do not contain two pairs of antipodal points....

  10. De bruikbaarheid van de ‘shaken baby syndroom’-hypothese in het strafproces

    NARCIS (Netherlands)

    Hoving, R.A.

    In het Nederlandse strafproces wordt regelmatig gebruik gemaakt van deskundigenbewijs van deskundigen die uitgaan van de ‘shaken baby syndroom’-hypothese om aan te tonen dat een verdachte een baby heeft mishandeld of gedood. In onder meer de Verenigde Staten en Engeland woedt een felle discussie

  11. Gender Relations and Economic Development: Hypotheses about the Reversal of Fortune in EurAsia

    NARCIS (Netherlands)

    de Pleijt, A.M.; van Zanden, J.L.; Carmichael, S.G.

    2016-01-01

    This paper develops an interrelated set of hypotheses about the links between gender relations, family systems and economic development in EurAsia. Firstly, we briefly discuss a number of ideas from the recent literature about the links between gender relations and economic development. Secondly, we

  12. Williams Syndrome Hypersociability: A Neuropsychological Study of the Amygdala and Prefrontal Cortex Hypotheses

    Science.gov (United States)

    Capitao, Liliana; Sampaio, Adriana; Fernandez, Montse; Sousa, Nuno; Pinheiro, Ana; Goncalves, Oscar F.

    2011-01-01

    Individuals with Williams syndrome display indiscriminate approach towards strangers. Neuroimaging studies conducted so far have linked this social profile to structural and/or functional abnormalities in WS amygdala and prefrontal cortex. In this study, the neuropsychological hypotheses of amygdala and prefrontal cortex involvement in WS…

  13. A Comprehensive Framework for Evaluating Hypotheses about Cultural Bias in Educational Testing

    Science.gov (United States)

    Banks, Kathleen

    2006-01-01

    The purpose of this article is to present a working definition of the term "culture," as well as to describe and demonstrate a comprehensive framework for evaluating hypotheses about cultural bias in educational testing. The framework is demonstrated using 5th-grade reading and language arts data from the Terra Nova test (CTB/McGraw-Hill, 1999).…

  14. ADOPTING SOCIO-DEMOGRAPHIC CHARACTERISTICS IN PROFILING GREEN CONSUMERS: A REVIEW OF HYPOTHESES

    Directory of Open Access Journals (Sweden)

    Arif Hartono

    2009-02-01

    Full Text Available In the last three decades worldwide environmental consciousness has increased dramatically as well as profiling green consumers have gained tremendous attention in the past. Segmenting and targeting markets base on pro-environmental purchase behavior are essential when companies positioning their green products. Socio-demographic characteristics have gained a lot of attention as the key profiling variables. Such characteristics have been employed by many scholars more frequently for the bases of segmenting and profiling green consumers. However, most existing studies of green consumers’ socio-demographic were US based. The present article attempts to review the common hypotheses of socio-demographic characteristics in profiling green consumers. The present article reviews five general hypotheses relating to socio-demographics and environmental consciousness of green consumers, namely the gender, age, education level, income, and occupation hypotheses, as well as the theoretical explanation for each hypothesis. Most previous studies tend to have the same conclusion in the gender, age, education level, and  income characteristics. Critics to socio-demographic characteristics and a need to conduct green marketing research in Indonesia was also reviewed.Key words: profiling, socio-demographic, green consumer, hypotheses.

  15. Disagreement and causal learning: others' hypotheses affect children's evaluations of evidence.

    Science.gov (United States)

    Young, Andrew G; Alibali, Martha W; Kalish, Charles W

    2012-09-01

    When children evaluate evidence and make causal inferences, they are sensitive to the social context in which data are generated. This study investigated whether children learn more from evidence generated by an agent who agrees with them or from one who disagrees with them. Children in two age groups (5- and 6-year-olds and 9- and 10-year-olds) observed the functioning of a machine that lit up and played music in the presence of certain objects. After endorsing one of two plausible causal hypotheses, children observed a puppet either agree or disagree with their own hypotheses. The puppet then generated a further piece of evidence that confirmed, disconfirmed, or was neutral with respect to the children's hypotheses. When they were later asked to make causal inferences about objects they did not directly observe, children in both age groups responded differentially to identical evidence depending on whether the agent agreed or disagreed, and they often drew stronger inferences in response to disagreement. In addition, older children were particularly sensitive to disagreement when the evidence was ambiguous. Our results suggest that children consider the relationship between their own and others' hypotheses when evaluating evidence that others generate. PsycINFO Database Record (c) 2012 APA, all rights reserved.

  16. Support for major hypotheses in invasion biology is uneven and declining

    Czech Academy of Sciences Publication Activity Database

    Jeschke, J.M.; Aparicio, L.G.; Haider, S.; Heger, T.; Lortie, C. J.; Pyšek, Petr; Strayer, D.L.

    2012-01-01

    Roč. 2012, č. 14 (2012), s. 1-20 ISSN 1619-0033 R&D Projects: GA ČR(CZ) GAP504/11/1028 Institutional support : RVO:67985939 Keywords : biological invasions * hypotheses * testing Subject RIV: EF - Botanics

  17. Testing hypotheses that link wood anatomy to cavitation resistance and hydraulic conductivity in the genus Acer

    NARCIS (Netherlands)

    Lens, F.; Sperry, J.S.; Christmas, M.A.; Rabaey, D.; Jansen, S.

    2011-01-01

    • Vulnerability to cavitation and conductive efficiency depend on xylem anatomy. We tested a large range of structure–function hypotheses, some for the first time, within a single genus to minimize phylogenetic ‘noise’ and maximize detection of functionally relevant variation. • This integrative

  18. Method of Check of Statistical Hypotheses for Revealing of “Fraud” Point of Sale

    Directory of Open Access Journals (Sweden)

    T. M. Bolotskaya

    2011-06-01

    Full Text Available Application method checking of statistical hypotheses fraud Point of Sale working with purchasing cards and suspected of accomplishment of unauthorized operations is analyzed. On the basis of the received results the algorithm is developed, allowing receive an assessment of works of terminals in regime off-line.

  19. Bullying Victimization and Adolescent Self-Harm: Testing Hypotheses from General Strain Theory

    Science.gov (United States)

    Hay, Carter; Meldrum, Ryan

    2010-01-01

    Self-harm is widely recognized as a significant adolescent social problem, and recent research has begun to explore its etiology. Drawing from Agnew's (1992) social psychological strain theory of deviance, this study considers this issue by testing three hypotheses about the effects of traditional and cyber bullying victimization on deliberate…

  20. Why Consumers Choose Managed Mutual Funds over Index Funds: Hypotheses from Consumer Behavior.

    Science.gov (United States)

    Lichtenstein, Donald R.; Kaufmann, Patrick J.; Bhagat, Sanjai

    1999-01-01

    Using the literature of psychology, consumer behavior, and behavioral finance, a series of hypotheses is presented that account for consumer choices of managed over index mutual funds. Results indicate a need for consumer education to increase awareness of the benefits of index investing. (SK)

  1. Utility of Krashen's Five Hypotheses in the Saudi Context of Foreign Language Acquisition/Learning

    Science.gov (United States)

    Gulzar, Malik Ajmal; Gulnaz, Fahmeeda; Ijaz, Attiya

    2014-01-01

    In the last twenty years, the paradigm that has dominated the discipline of language teaching is the SLA theory and Krashen's five hypotheses which are still proving flexible to accommodate earlier reforms. This paper reviews second language acquisition (SLA) theory to establish an understanding of its role in the EFL/ESL classrooms. Other areas…

  2. The Association between Relational Aggression and Perceived Popularity in Early Adolescence: A Test of Competing Hypotheses

    Science.gov (United States)

    Gangel, Meghan J.; Keane, Susan P.; Calkins, Susan D.; Shanahan, Lilly; O'Brien, Marion

    2017-01-01

    This study examined two competing hypotheses regarding the moderators of the association between relational aggression and peer status in early adolescence. The "mitigation relational aggression" hypothesis examined whether positive social behaviors reduced the negative effects of relational aggression, thus amplifying the association…

  3. Distinguishing hypotheses from hyperbole in studies of media violence: A comment on Markey et al

    NARCIS (Netherlands)

    Bushman, B.J.; Romer, D.; Jamieson, P.E.

    2015-01-01

    In alleging that Bushman et al. (2013) made sensational and unsubstantiated claims, Markey et al. (2015) mistake hypotheses for hyperbole. Moreover, in their effort to show that gun violence in PG-13 movies (for ages 13 and older) is unrelated to trends in population violence, they make unjustified

  4. Aggression among Children with ADHD, Anxiety, or Co-Occurring Symptoms: Competing Exacerbation and Attenuation Hypotheses

    Science.gov (United States)

    Becker, Stephen P.; Luebbe, Aaron M.; Stoppelbein, Laura; Greening, Leilani; Fite, Paula J.

    2012-01-01

    Competing hypotheses for explaining the role of anxiety in the relation between attention-deficit/hyperactivity disorder (ADHD) symptoms and childhood aggression were evaluated. Two studies tested whether anxiety exacerbated, attenuated, or had no effect on the relation between ADHD and aggression subtypes among psychiatrically hospitalized…

  5. Cross-Cultural Business Communication Research: State of the Art and Hypotheses for the 1990s.

    Science.gov (United States)

    Limaye, Mohan R.; Victor, David A.

    1991-01-01

    Reviews the scholarly literature in cross-cultural business communication and discusses its shortcomings. Demonstrates the limitations of the Western, linear paradigms and expounds upon some inadequately researched and unresolved important questions. Develops 10 testable hypotheses for the 1990s. Advocates developing new paradigms and concept…

  6. Hypotheses on citation practices as revealed in the literature of the ...

    African Journals Online (AJOL)

    Citations found in two historical articles, which appeared in Cancer Research, a top American Journal, were used to show both positive and negative attitudes towards my 22 historical publications on cancer carriage in the body. Therefore, scientific information concepts are cited critically and two hypotheses are advanced ...

  7. Improving the Development of Student's Research Questions and Hypotheses in an Introductory Business Research Methods Course

    Science.gov (United States)

    Strangman, Lauria; Knowles, Elizabeth

    2012-01-01

    In an introductory research methods course, students often develop research questions and hypotheses that are vague or confusing, do not contain measurable concepts, and are too narrow in scope or vision. Because of this, the final research projects often fail to provide useful information or address the overall research problem. A Lesson Study…

  8. Use of hypotheses for analysis of variance models: challenging the current practice

    NARCIS (Netherlands)

    van Wesel, F.; Boeije, H.R.; Hoijtink, H.

    2013-01-01

    In social science research, hypotheses about group means are commonly tested using analysis of variance. While deemed to be formulated as specifically as possible to test social science theory, they are often defined in general terms. In this article we use two studies to explore the current

  9. Use of hypotheses for analysis of variance Models: Challenging the current practice

    NARCIS (Netherlands)

    van Wesel, F.; Boeije, H.R.; Hoijtink, H

    2013-01-01

    In social science research, hypotheses about group means are commonly tested using analysis of variance. While deemed to be formulated as specifically as possible to test social science theory, they are often defined in general terms. In this article we use two studies to explore the current

  10. Use of hypotheses for analysis of variance models: challenging the current practice.

    NARCIS (Netherlands)

    Wesel, F. van; Boeije, H.; Hoijtink, H.

    2013-01-01

    In social science research, hypotheses about group means are commonly tested using analysis of variance. While deemed to be formulated as specifically as possible to test social science theory, they are often defined in general terms. In this article we use two studies to explore the current

  11. Coping with the Stigma of Mental Illness: Empirically-Grounded Hypotheses from Computer Simulations

    Science.gov (United States)

    Kroska, Amy; Har, Sarah K.

    2011-01-01

    This research demonstrates how affect control theory and its computer program, "Interact", can be used to develop empirically-grounded hypotheses regarding the connection between cultural labels and behaviors. Our demonstration focuses on propositions in the modified labeling theory of mental illness. According to the MLT, negative societal…

  12. Delinquency and Peer Acceptance in Adolescence: A Within-Person Test of Moffitt's Hypotheses

    Science.gov (United States)

    Rulison, Kelly L.; Kreager, Derek A.; Osgood, D. Wayne

    2014-01-01

    We tested 2 hypotheses derived from Moffitt's (1993) taxonomic theory of antisocial behavior, both of which are central to her explanation for the rise in delinquency during adolescence. We tested whether persistently delinquent individuals become more accepted by their peers during adolescence and whether individuals who abstain from delinquent…

  13. Peridynamic Multiscale Finite Element Methods

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Timothy [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bond, Stephen D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Littlewood, David John [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Moore, Stan Gerald [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-12-01

    The problem of computing quantum-accurate design-scale solutions to mechanics problems is rich with applications and serves as the background to modern multiscale science research. The prob- lem can be broken into component problems comprised of communicating across adjacent scales, which when strung together create a pipeline for information to travel from quantum scales to design scales. Traditionally, this involves connections between a) quantum electronic structure calculations and molecular dynamics and between b) molecular dynamics and local partial differ- ential equation models at the design scale. The second step, b), is particularly challenging since the appropriate scales of molecular dynamic and local partial differential equation models do not overlap. The peridynamic model for continuum mechanics provides an advantage in this endeavor, as the basic equations of peridynamics are valid at a wide range of scales limiting from the classical partial differential equation models valid at the design scale to the scale of molecular dynamics. In this work we focus on the development of multiscale finite element methods for the peridynamic model, in an effort to create a mathematically consistent channel for microscale information to travel from the upper limits of the molecular dynamics scale to the design scale. In particular, we first develop a Nonlocal Multiscale Finite Element Method which solves the peridynamic model at multiple scales to include microscale information at the coarse-scale. We then consider a method that solves a fine-scale peridynamic model to build element-support basis functions for a coarse- scale local partial differential equation model, called the Mixed Locality Multiscale Finite Element Method. Given decades of research and development into finite element codes for the local partial differential equation models of continuum mechanics there is a strong desire to couple local and nonlocal models to leverage the speed and state of the

  14. University Rankings

    Directory of Open Access Journals (Sweden)

    Telichenko Valeriy Ivanovich

    2014-06-01

    Full Text Available The article gives the analysis of university rankings and defines the differences in evaluation methods and indicators of world ranking agencies, presents new approaches to making global rankings. It defines the position of MGSU in Russian universities TOP-100 ranking. University rankings are not simply information, but the evaluation instrument of quality of education, initiating the improvement of ranking position. It’s important for Russian Universities claiming for higher positions in the world rankings. MGSU position in universities ranking made the University administration consider thoroughly the University positioning in the system of higher education, in the categories of education and science and among possible employers of the university graduates.

  15. Flexoelectric effect in finite samples

    Science.gov (United States)

    Tagantsev, Alexander K.; Yurkov, Alexander S.

    2012-08-01

    Static flexoelectric effect in a finite sample of a solid is addressed in terms of phenomenological theory for the case of a thin plate subjected to bending. It has been shown that despite an explicit asymmetry inherent to the bulk constitutive electromechanical equations which take into account the flexoelectric coupling, there exists a situation where electromechanical response for a finite sample is "symmetric." "Symmetric" means that if a sensor and an actuator are made of a flexoelectric element, performance of such devices can be characterized by the same effective piezoelectric coefficient. This behavior is consistent with the thermodynamic arguments offered earlier, being in conflict with the current point of view on the matter in literature. This result was obtained using standard mechanical boundary conditions valid for the case where the polarization vanishes at the surface. It was shown that, for the case where the polarization at the surface is not zero, the aforementioned symmetry of electromechanical response may be violated if standard mechanical boundary conditions are used, leading to a conflict with the thermodynamic arguments. It is suggested that this conflict may be resolved when using modified mechanical boundary conditions. It is also shown that the contribution of surface piezoelectricity to the flexoelectric response of a finite sample is expected to be comparable to that of the static bulk contribution (including materials with high values of the dielectric constant) and to scale as the bulk value of the dielectric constant (similar to the bulk contribution). This finding implies that if the experimentally measured flexoelectric coefficient scales as the dielectric constant of the material, this does not imply that the measured flexoelectric response is controlled by the static bulk contribution to the flexoelectric effect.

  16. Declining forest productivity in aging forest stands: a modeling analysis of alternative hypotheses.

    Science.gov (United States)

    Murty, Danuse; McMurtrie, Ross E.; Ryan, Michael G.

    1996-01-01

    Several explanations have been advanced to account for the decline in forest net primary productivity (NPP) with age in closed-canopy stands including the hypotheses that: (1) sapwood maintenance respiration rate increases, reducing the availability of carbon to support new growth; (2) stomatal conductance and hence photosynthetic efficiency decline; and (3) soil nutrient availability declines. To evaluate these hypotheses we applied the ecosystem model G'DAY to a 40- and a 245-year-old stand of lodgepole pine (Pinus contorta Dougl. ex Loud.), growing on infertile soils. Net primary productivity estimated from biomass data was 0.47 and 0.25 kg C m(-2) year(-1) and foliar nitrogen/carbon ratio (N/C) was 0.0175 and 0.017 for the 40- and 245-year-old stands, respectively. Productivities of the young and old stands were derived from a graphical analysis of the G'DAY model. The graphical analysis also indicated that the observed age-related decline in NPP can be explained in terms of interacting processes associated with Hypotheses 2 and 3. However, the relative importance of these two hypotheses differed depending on key model assumptions, in particular those relating to variation in soil N/C ratio. Thus, if we assumed that soil N/C ratio can vary significantly during stand development, then Hypotheses 2 and 3 jointly explain the decline in NPP, whereas if we assumed that soil N/C ratios are constant, then Hypothesis 3 alone explains the decline in NPP. The analysis revealed that only a small fraction of the decline of NPP can be explained in terms of increasing sapwood respiration.

  17. Entropy conservative finite element schemes

    Science.gov (United States)

    Tadmor, E.

    1986-01-01

    The question of entropy stability for discrete approximations to hyperbolic systems of conservation laws is studied. The amount of numerical viscosity present in such schemes is quantified and related to their entropy stability by means of comparison. To this end, two main ingredients are used: entropy variables and the construction of certain entropy conservative schemes in terms of piecewise-linear finite element approximations. It is then shown that conservative schemes are entropy stable, if and (for three-point schemes) only if, they contain more numerical viscosity than the abovementioned entropy conservation ones.

  18. Finite Higgs mass without Supersymmetry

    CERN Document Server

    Antoniadis, Ignatios; Quirós, Mariano

    2001-01-01

    We identify a class of chiral models where the one-loop effective potential for Higgs scalar fields is finite without any requirement of supersymmetry. It corresponds to the case where the Higgs fields are identified with the components of a gauge field along compactified extra dimensions. We present a six dimensional model with gauge group U(3)xU(3) and quarks and leptons accomodated in fundamental and bi-fundamental representations. The model can be embedded in a D-brane configuration of type I string theory and, upon compactification on a T^2/Z_2 orbifold, it gives rise to the standard model with two Higgs doublets.

  19. Multigrid Finite Element Method in Calculation of 3D Homogeneous and Composite Solids

    Directory of Open Access Journals (Sweden)

    A.D. Matveev

    2016-12-01

    Full Text Available In the present paper, a method of multigrid finite elements to calculate elastic three-dimensional homogeneous and composite solids under static loading has been suggested. The method has been developed based on the finite element method algorithms using homogeneous and composite three-dimensional multigrid finite elements (MFE. The procedures for construction of MFE of both rectangular parallelepiped and complex shapes have been shown. The advantages of MFE are that they take into account, following the rules of the microapproach, heterogeneous and microhomogeneous structures of the bodies, describe the three-dimensional stress-strain state (without any simplifying hypotheses in homogeneous and composite solids, as well as generate small dimensional discrete models and numerical solutions with a high accuracy.

  20. Supersymmetry breaking at finite temperature

    International Nuclear Information System (INIS)

    Kratzert, K.

    2002-11-01

    The mechanism of supersymmetry breaking at finite temperature is still only partly understood. Though it has been proven that temperature always breaks supersymmetry, the spontaneous nature of this breaking remains unclear, in particular the role of the Goldstone fermion. The aim of this work is to unify two existing approaches to the subject. From a hydrodynamic point of view, it has been argued under very general assumptions that in any supersymmetric quantum field theory at finite temperature there should exist a massless fermionic collective excitation, named phonino because of the analogy to the phonon. In the framework of a self-consistent resummed perturbation theory, it is shown for the example of the Wess-Zumino model that this mode fits very well into the quantum field theoretical framework pursued by earlier works. Interpreted as a bound state of boson and fermion, it contributes to the supersymmetric Ward-Takahashi identities in a way showing that supersymmetry is indeed broken spontaneously with the phonino playing the role of the Goldstone fermion. The second part of the work addresses the case of supersymmetric quantum electrodynamics. It is shown that also here the phonino exists and must be interpreted as the Goldstone mode. This knowledge allows a generalization to a wider class of models. (orig.)

  1. Finite Unification: Theory and Predictions

    CERN Document Server

    Heinemeyer, S; Zoupanos, G

    2010-01-01

    All-loop Finite Unified Theories (FUTs) are very interesting N=1 supersymmetric Grand Unified Theories (GUTs) which not only realise an old field theoretic dream but also have a remarkable predictive power due to the required reduction of couplings. The reduction of the dimensionless couplings in N=1 GUTs is achieved by searching for renormalization group invariant (RGI) relations among them holding beyond the unification scale. Finiteness results from the fact that there exist RGI relations among dimensionless couplings that guarantee the vanishing of all beta-functions in certain N=1 GUTs even to all orders. Furthermore developments in the soft supersymmetry breaking sector of N=1 GUTs and FUTs lead to exact RGI relations, i.e. reduction of couplings, in this dimensionful sector of the theory too. Based on the above theoretical framework phenomenologically consistent FUTS have been constructed. Here we present FUT models based on the SU(5) and SU(3)^3 gauge groups and their predictions. Of particular intere...

  2. Biset functors for finite groups

    CERN Document Server

    Bouc, Serge

    2010-01-01

    This volume exposes the theory of biset functors for finite groups, which yields a unified framework for operations of induction, restriction, inflation, deflation and transport by isomorphism. The first part recalls the basics on biset categories and biset functors. The second part is concerned with the Burnside functor and the functor of complex characters, together with semisimplicity issues and an overview of Green biset functors. The last part is devoted to biset functors defined over p-groups for a fixed prime number p. This includes the structure of the functor of rational representations and rational p-biset functors. The last two chapters expose three applications of biset functors to long-standing open problems, in particular the structure of the Dade group of an arbitrary finite p-group.This book is intended both to students and researchers, as it gives a didactic exposition of the basics and a rewriting of advanced results in the area, with some new ideas and proofs.

  3. Neutrinos in the universe

    International Nuclear Information System (INIS)

    Tayler, R.J.

    1981-01-01

    Although neutrinos are apparently insignificant particles, which were not discovered for more than 25 years after their existence was predicted, they have had a big influence on the evolution of the Universe, particularly if it had a hot origin. Their importance may be increased if recent suggestions that their mass is finite are confirmed. In this article a brief account is given of the properties of neutrinos and this is followed by a discussion of the way in which they influence the evolution of the hot big bang Universe and of their role in the late stages of stellar evolution. There is also a brief discussion of the problem of the solar neutrinos and of the manner in which neutrino instability might reduce or solve it. (author)

  4. Finite-size corrections for logarithmic representations in critical dense polymers

    Energy Technology Data Exchange (ETDEWEB)

    Izmailian, Nickolay Sh., E-mail: izmailan@phys.sinica.edu.tw [Institute of Physics, Academia Sinica, Nankang, Taipei 11529, Taiwan (China); Yerevan Physics Institute, Alikhanian Br. 2, 375036 Yerevan (Armenia); National Center for Theoretical Sciences, Physics Division, National Taiwan University, Taipei 10617, Taiwan (China); Ruelle, Philippe, E-mail: philippe.ruelle@uclouvain.be [Institut de Recherche en Mathematique et Physique, Universite catholique de Louvain, B-1348 Louvain-La-Neuve (Belgium); Hu, Chin-Kun, E-mail: huck@phys.sinica.edu.tw [Institute of Physics, Academia Sinica, Nankang, Taipei 11529, Taiwan (China)

    2012-05-01

    We study (analytic) finite-size corrections in the dense polymer model on the strip by perturbing the critical Hamiltonian with irrelevant operators belonging to the tower of the identity. We generalize the perturbation expansion to include Jordan cells, and examine whether the finite-size corrections are sensitive to the properties of indecomposable representations appearing in the conformal spectrum, in particular their indecomposability parameters. We find, at first order, that the corrections do not depend on these parameters nor even on the presence of Jordan cells. Though the corrections themselves are not universal, the ratios are universal and correctly reproduced by the conformal perturbative approach, to first order.

  5. Bulk flows in the universe: Pt. 1

    International Nuclear Information System (INIS)

    Kaiser, Nick

    1990-01-01

    A recent observational advance has been the mapping of the expansion pattern of the universe in the neighbourhood of the Milky Way. These studies reveal significant departures from uniform Hubble expansion, thought to be associated with the growth of superclusters. In this review I discuss currently popular hypotheses concerning how structure in our universe might have originated and its current evolution. (author)

  6. NegaWatt 2011-2050 scenario - Hypotheses and method. Technical report, May 2014

    International Nuclear Information System (INIS)

    2014-05-01

    This report proposes an analysis of the negaWatt 2011 scenario. It describes in detail the methodology adopted to elaborate this prospective scenario, and presents the major part of the hypotheses which structure this scenario. A first part presents the approach and methodology (constraints, scenario, model). The second part addresses the issue of energy saving and energy efficiency through a sector-based analysis (housing and office building, transports, industrial and agricultural production). The third part studies the substitution by renewable energies through a supply analysis: energy production based on biomass, renewable energies, and fissile and fossil energies. It outlines the major role of grids in the supply-demand balance. The results of the negaWatt 2011 scenario are presented in terms of final energy, primary energies, and impact on greenhouse gas emissions. Hypotheses and results related to the different sectors (building, transports, industry and agriculture, energy production) are given in appendix

  7. Environmental risk factors (excluding tobacco and microorganisms): critical analysis of old and new hypotheses.

    Science.gov (United States)

    Ekbom, Anders; Montgomery, Scott M

    2004-06-01

    The increase in incidence in both ulcerative colitis and Crohn's disease during the 20th century has led to an abundance of different hypotheses on what sort of exposures are responsible. There has been a special focus on dietary factors, as well as on other exposures introduced on a population-based level, including fast food, cola drinks, toothpaste, antibiotics and oral contraceptives. The aim of this review is to critically assess the results from the different observational studies that have investigated these hypotheses, and also to propose research agendas that should be pursued in the future. The conclusion is that infectious exposures and early bacterial colonization, which are associated with better hygiene early in life and that influence immune function, and possibly oral contraceptives, remain the only exposures of interest for future research into the aetiology of ulcerative colitis and Crohn's disease.

  8. Human ecology in pathogenic landscapes: two hypotheses on how land use change drives viral emergence

    Science.gov (United States)

    Murray, Kris. A.; Daszak, Peter

    2013-01-01

    The emergence of novel viral diseases is driven by socioeconomic, demographic and environmental changes. These include land use changes such as deforestation, agricultural expansion and habitat degradation. However, the links between land use change and disease emergence are poorly understood and likely complex. In this review, we propose two hypotheses for the mechanisms by which land use change can lead to viral emergence: 1) by perturbing disease dynamics in multi-host disease systems via impacts on cross-species transmission rates (the ‘perturbation’ hypothesis); and 2) by allowing exposure of novel hosts to a rich pool of pathogen diversity (the ‘pathogen pool’ hypothesis). We discuss ways that these two hypotheses might be tested using a combination of ecological and virological approaches, and how this may provide novel control and prevention strategies. PMID:23415415

  9. Gender Relations and Economic Development: Hypotheses about the Reversal of Fortune in EurAsia

    OpenAIRE

    de Pleijt, A.M.; van Zanden, J.L.; Carmichael, S.G.

    2016-01-01

    This paper develops an interrelated set of hypotheses about the links between gender relations, family systems and economic development in EurAsia. Firstly, we briefly discuss a number of ideas from the recent literature about the links between gender relations and economic development. Secondly, we suggest a measure of historic gender relations via the classification and measurement of historical family systems, and offer a set of maps of the institutions concerning marriage, inheritance and...

  10. How doctors generate diagnostic hypotheses: a study of radiological diagnosis with functional magnetic resonance imaging.

    Directory of Open Access Journals (Sweden)

    Marcio Melo

    Full Text Available In medical practice, diagnostic hypotheses are often made by physicians in the first moments of contact with patients; sometimes even before they report their symptoms. We propose that generation of diagnostic hypotheses in this context is the result of cognitive processes subserved by brain mechanisms that are similar to those involved in naming objects or concepts in everyday life.To test this proposal we developed an experimental paradigm with functional magnetic resonance imaging (fMRI using radiological diagnosis as a model. Twenty-five radiologists diagnosed lesions in chest X-ray images and named non-medical targets (animals embedded in chest X-ray images while being scanned in a fMRI session. Images were presented for 1.5 seconds; response times (RTs and the ensuing cortical activations were assessed. The mean response time for diagnosing lesions was 1.33 (SD ±0.14 seconds and 1.23 (SD ±0.13 seconds for naming animals. 72% of the radiologists reported cogitating differential diagnoses during trials (3.5 seconds. The overall pattern of cortical activations was remarkably similar for both types of targets. However, within the neural systems shared by both stimuli, activation was significantly greater in left inferior frontal sulcus and posterior cingulate cortex for lesions relative to animals.Generation of diagnostic hypotheses and differential diagnoses made through the immediate visual recognition of clinical signs can be a fast and automatic process. The co-localization of significant brain activation for lesions and animals suggests that generating diagnostic hypotheses for lesions and naming animals are served by the same neuronal systems. Nevertheless, diagnosing lesions was cognitively more demanding and associated with more activation in higher order cortical areas. These results support the hypothesis that medical diagnoses based on prompt visual recognition of clinical signs and naming in everyday life are supported by similar

  11. Statistical analysis of hypotheses on the cointegrating relations in the I(2) model

    DEFF Research Database (Denmark)

    Johansen, Søren

    2006-01-01

    The cointegrated vector autoregressive model for I(2) variables is a non-linear parametric restriction on the linear I(2) regression model for variables of order I(0), I(1) and I(2). In this paper we discuss non-linear submodels given by smooth parametrizations. We give conditions on the parametr......) and the reformulation is applied to show that some hypotheses on the cointegrating coefficients in the cointegrated I(2) model give asymptotic ¿² inference....

  12. Economic and evolutionary hypotheses for cross-population variation in parochialism

    Directory of Open Access Journals (Sweden)

    Daniel Jacob Hruschka

    2013-09-01

    Full Text Available Human populations differ reliably in the degree to which people favor family, friends and community members over strangers and outsiders. In the last decade, researchers have begun to propose several economic and evolutionary hypotheses for these cross-population differences in parochialism. In this paper, we outline major current theories and review recent attempts to test them. We also discuss the key methodological challenges in assessing these diverse economic and evolutionary theories for cross-population differences in parochialism.

  13. Finite size scaling and lattice gauge theory

    International Nuclear Information System (INIS)

    Berg, B.A.

    1986-01-01

    Finite size (Fisher) scaling is investigated for four dimensional SU(2) and SU(3) lattice gauge theories without quarks. It allows to disentangle violations of (asymptotic) scaling and finite volume corrections. Mass spectrum, string tension, deconfinement temperature and lattice β-function are considered. For appropriate volumes, Monte Carlo investigations seem to be able to control the finite volume continuum limit. Contact is made with Luescher's small volume expansion and possibly also with the asymptotic large volume behavior. 41 refs., 19 figs

  14. Domain decomposition methods for mortar finite elements

    Energy Technology Data Exchange (ETDEWEB)

    Widlund, O.

    1996-12-31

    In the last few years, domain decomposition methods, previously developed and tested for standard finite element methods and elliptic problems, have been extended and modified to work for mortar and other nonconforming finite element methods. A survey will be given of work carried out jointly with Yves Achdou, Mario Casarin, Maksymilian Dryja and Yvon Maday. Results on the p- and h-p-version finite elements will also be discussed.

  15. Semiprojectivity of universal -algebras generated by algebraic elements

    DEFF Research Database (Denmark)

    Shulman, Tatiana

    2012-01-01

    Let be a polynomial in one variable whose roots all have multiplicity more than 1. It is shown that the universal -algebra of a relation , , is semiprojective and residually finite-dimensional. Applications to polynomially compact operators are given....

  16. Controversial hypotheses on the relationship between researcher and informant in qualitative research.

    Science.gov (United States)

    Wilde, V

    1992-02-01

    This paper addresses methodological issues that emerged unexpectedly during a qualitative study set up to explore nurses' descriptions of difficult, challenging and satisfying experiences at work. The purpose of the study had been to look for critical factors influencing nurses' perceptions of their performance in specific situations, and their labelling of each event. Ten nurses were asked to describe in detail three events; a difficult situation in which they had coped well, a difficult situation in which they would like to have coped better, and a satisfying or rewarding situation. The critical incident technique was used. Rich descriptions were obtained, tape recorded, transcribed verbatum, and analysed by constant comparative analysis, following the principles of grounded theory. Some suprising hypotheses emerged regarding the methodology of the informal interview in qualitative research. This paper addresses these hypotheses, which focus on the interaction between the researcher and informant, the role conflict facing the nurse researcher, the effect of the researcher's past experience on the interaction, the use of counselling strategies and the principle of self-disclosure. These hypotheses were incidental to the original area of study and were more exciting in their emergence because of this.

  17. Validity of the Environmental Kuznets Curve Hypotheses in Water Pollution A Case Study

    Directory of Open Access Journals (Sweden)

    Hediyeh Alishiri

    2017-03-01

    Full Text Available Among the different environmental pollutions, water pollution is of especial importance due to the rather unchanging supply of this vital resource on a global scale and because of the dire consequences of its pollution for human health. The relationship between water production and its pollution can thus established and used as a measure of environmental degradation. This relationship can then be captured and analyzed in terms of environmental Kuznets hypotheses. It may be claimed that the early stages of economic growth is associated with lower per capita income and water pollution but the trend is reversed with increasing per capita income and improved economic growth. The present study was conducted using the panel data technique and the Kuznets environmental hypotheses were examined for the two groups of developed and developing countries under the two scenarios of using either per capita GDP or the share of industry to the added value in GDP as an indicator of economic growth. Results indicate that under both scenarios, Kuznets hypotheses are confirmed when studying the situation in developing countries but refuted in the case of developed countries.

  18. Using climate, energy, and spatial-based hypotheses to interpret macroecological patterns of North America chelonians

    Science.gov (United States)

    Ennen, Joshua R.; Agha, Mickey; Matamoros, Wilfredo A.; Hazzard, Sarah C.; Lovich, Jeffrey E.

    2016-01-01

    Our study investigates how factors, such as latitude, productivity, and several environmental variables, influence contemporary patterns of the species richness in North American turtles. In particular, we test several hypotheses explaining broad-scale species richness patterns on several species richness data sets: (i) total turtles, (ii) freshwater turtles only, (iii) aquatic turtles, (iv) terrestrial turtles only, (v) Emydidae, and (vi) Kinosternidae. In addition to spatial data, we used a combination of 25 abiotic variables in spatial regression models to predict species richness patterns. Our results provide support for multiple hypotheses related to broad-scale patterns of species richness, and in particular, hypotheses related to climate, productivity, water availability, topography, and latitude. In general, species richness patterns were positively associated with temperature, precipitation, diversity of streams, coefficient of variation of elevation, and net primary productivity. We also found that North America turtles follow the general latitudinal diversity gradient pattern (i.e., increasing species richness towards equator) by exhibiting a negative association with latitude. Because of the incongruent results among our six data sets, our study highlights the importance of considering phylogenetic constraints and guilds when interpreting species richness patterns, especially for taxonomic groups that occupy a myriad of habitats.

  19. ANSYS duplicate finite-element checker routine

    Science.gov (United States)

    Ortega, R.

    1995-01-01

    An ANSYS finite-element code routine to check for duplicated elements within the volume of a three-dimensional (3D) finite-element mesh was developed. The routine developed is used for checking floating elements within a mesh, identically duplicated elements, and intersecting elements with a common face. A space shuttle main engine alternate turbopump development high pressure oxidizer turbopump finite-element model check using the developed subroutine is discussed. Finally, recommendations are provided for duplicate element checking of 3D finite-element models.

  20. A first course in finite elements

    CERN Document Server

    Fish, Jacob

    2007-01-01

    Developed from the authors, combined total of 50 years undergraduate and graduate teaching experience, this book presents the finite element method formulated as a general-purpose numerical procedure for solving engineering problems governed by partial differential equations.  Focusing on the formulation and application of the finite element method through the integration of finite element theory, code development, and software application, the book is both introductory and self-contained, as well as being a hands-on experience for any student. This authoritative text on Finite Elements:Adopts

  1. Learning Extended Finite State Machines

    Science.gov (United States)

    Cassel, Sofia; Howar, Falk; Jonsson, Bengt; Steffen, Bernhard

    2014-01-01

    We present an active learning algorithm for inferring extended finite state machines (EFSM)s, combining data flow and control behavior. Key to our learning technique is a novel learning model based on so-called tree queries. The learning algorithm uses the tree queries to infer symbolic data constraints on parameters, e.g., sequence numbers, time stamps, identifiers, or even simple arithmetic. We describe sufficient conditions for the properties that the symbolic constraints provided by a tree query in general must have to be usable in our learning model. We have evaluated our algorithm in a black-box scenario, where tree queries are realized through (black-box) testing. Our case studies include connection establishment in TCP and a priority queue from the Java Class Library.

  2. Axisymmetric finite deformation membrane problems

    Energy Technology Data Exchange (ETDEWEB)

    Feng, W.W.

    1980-12-12

    Many biomechanic problems involve the analysis of finite deformation axisymmetric membranes. This paper presents the general formulation for solving a class of axisymmetric membrane problems. The material nonlinearity, as well as the geometric nonlinearity, is considered. Two methods are presented to solve these problems. The first method is solving a set of differential equilibrium equations. The governing equations are reduced to three first-order ordinary-differential equations with explicit derivatives. The second method is the Ritz method where a general potential energy functional valid for all axisymmetric deformed positions is presented. The geometric admissible functions that govern the deformed configuration are written in terms of a series with unknown coefficients. These unknown coefficients are determined by the minimum potential energy principle that of all geometric admissible deformed configurations, the equilibrium configuration minimizes the potential energy. Some examples are presented. A comparison between these two methods is mentioned.

  3. Finite volume schemes for Vlasov

    Directory of Open Access Journals (Sweden)

    Crouseilles Nicolas

    2013-01-01

    Full Text Available We present finite volume schemes for the numerical approximation of the one-dimensional Vlasov-Poisson equation (FOV CEMRACS 2011 project. Stability analysis is performed for the linear advection and links with semi-Lagrangian schemes are made. Finally, numerical results enable to compare the different methods using classical plasma test cases. Des schémas de type volumes finis sont étudiés ici pour l’approximation de l’équation de Vlasov-Poisson (projet FOV, CEMRACS 2011. Une analyse de stabilité est effectuée dans le cas de l’advection linéaire et plusieurs liens sont faits entre les méthodes volumes finis et semi-Lagrangiennes. Enfin, les méthodes sont comparées sur des cas tests académiques de la physique des plasmas.

  4. Phase transition in finite systems

    International Nuclear Information System (INIS)

    Chomaz, Ph.; Duflot, V.; Duflot, V.; Gulminelli, F.

    2000-01-01

    In this paper we present a review of selected aspects of Phase transitions in finite systems applied in particular to the liquid-gas phase transition in nuclei. We show that the problem of the non existence of boundary conditions can be solved by introducing a statistical ensemble with an averaged constrained volume. In such an ensemble the microcanonical heat capacity becomes negative in the transition region. We show that the caloric curve explicitly depends on the considered transformation of the volume with the excitation energy and so does not bear direct informations on the characteristics of the phase transition. Conversely, partial energy fluctuations are demonstrated to be a direct measure of the equation of state. Since the heat capacity has a negative branch in the phase transition region, the presence of abnormally large kinetic energy fluctuations is a signal of the liquid gas phase transition. (author)

  5. Nuclear deformation at finite temperature.

    Science.gov (United States)

    Alhassid, Y; Gilbreth, C N; Bertsch, G F

    2014-12-31

    Deformation, a key concept in our understanding of heavy nuclei, is based on a mean-field description that breaks the rotational invariance of the nuclear many-body Hamiltonian. We present a method to analyze nuclear deformations at finite temperature in a framework that preserves rotational invariance. The auxiliary-field Monte Carlo method is used to generate a statistical ensemble and calculate the probability distribution associated with the quadrupole operator. Applying the technique to nuclei in the rare-earth region, we identify model-independent signatures of deformation and find that deformation effects persist to temperatures higher than the spherical-to-deformed shape phase-transition temperature of mean-field theory.

  6. Nuclear Deformation at Finite Temperature

    Science.gov (United States)

    Alhassid, Y.; Gilbreth, C. N.; Bertsch, G. F.

    2014-12-01

    Deformation, a key concept in our understanding of heavy nuclei, is based on a mean-field description that breaks the rotational invariance of the nuclear many-body Hamiltonian. We present a method to analyze nuclear deformations at finite temperature in a framework that preserves rotational invariance. The auxiliary-field Monte Carlo method is used to generate a statistical ensemble and calculate the probability distribution associated with the quadrupole operator. Applying the technique to nuclei in the rare-earth region, we identify model-independent signatures of deformation and find that deformation effects persist to temperatures higher than the spherical-to-deformed shape phase-transition temperature of mean-field theory.

  7. Finite rotation shells basic equations and finite elements for Reissner kinematics

    CERN Document Server

    Wisniewski, K

    2010-01-01

    This book covers theoretical and computational aspects of non-linear shells. Several advanced topics of shell equations and finite elements - not included in standard textbooks on finite elements - are addressed, and the book includes an extensive bibliography.

  8. Testing hypotheses of velocity and celerity at the catchment scale using ensemble hydrograph separation

    Science.gov (United States)

    Kirchner, James

    2017-04-01

    Making hydrological models more realistic requires both better physical understanding of their underlying processes, and more rigorous tests of the hypotheses that they embody. In the current model-testing paradigm, multiple interdependent hypotheses are combined to generate model predictions, which are then compared with observational time series that reflect multiple interdependent forcings. This approach is problematic in several respects. If the modeled time series does not match the observations, which of the model's many embedded hypotheses is falsified? Conversely, even if the model matches the data, how many of its underlying hypotheses could still be wrong, perhaps in offsetting ways? The essence of the problem is that if model simulations depend on many interacting hypotheses, and if observational data reflect many different environmental forcings, then comparisons of simulations against data will rarely be diagnostic tests of specific hypotheses in the model. For this reason, I have long argued for a different approach to hypothesis testing, in which key signatures of behavior are extracted from both model and data before they are compared (Kirchner et al., 1996; Kirchner, 2006). This approach allows one to isolate the model/data comparison as much as possible from potentially confounding factors in both the model and the data. One key signature of catchment behavior, which has challenged many hydrologic models, is the contrast between the relatively short timescales of hydrologic response to precipitation events, reflecting the celerity of hydraulic potentials, and the much longer timescales of water transport through the landscape, reflecting the velocity of water movement as tracked by passive tracers (Kirchner, 2003). Here I show how both the velocity and celerity of transport at the catchment scale can be quantified from hydrologic and isotopic time series. The conventional formula used for hydrograph separation can be converted into an equivalent

  9. Parallel iterative procedures for approximate solutions of wave propagation by finite element and finite difference methods

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S. [Purdue Univ., West Lafayette, IN (United States)

    1994-12-31

    Parallel iterative procedures based on domain decomposition techniques are defined and analyzed for the numerical solution of wave propagation by finite element and finite difference methods. For finite element methods, in a Lagrangian framework, an efficient way for choosing the algorithm parameter as well as the algorithm convergence are indicated. Some heuristic arguments for finding the algorithm parameter for finite difference schemes are addressed. Numerical results are presented to indicate the effectiveness of the methods.

  10. Finite Element Modeling of the Posterior Eye in Microgravity

    Science.gov (United States)

    Feola, Andrew; Raykin, Julia; Mulugeta, Lealem; Gleason, Rudolph; Myers, Jerry G.; Nelson, Emily S.; Samuels, Brian; Ethier, C. Ross

    2015-01-01

    Microgravity experienced during spaceflight affects astronauts in various ways, including weakened muscles and loss of bone density. Recently, visual impairment and intracranial pressure (VIIP) syndrome has become a major concern for space missions lasting longer than 30 days. Astronauts suffering from VIIP syndrome have changes in ocular anatomical and visual impairment that persist after returning to earth. It is hypothesized that a cephalad fluid shift in microgravity may increase the intracranial pressure (ICP), which leads to an altered biomechanical environment of the posterior globe and optic nerve sheath (ONS).Currently, there is a lack of knowledge of how elevated ICP may lead to vision impairment and connective tissue changes in VIIP. Our goal was to develop a finite element model to simulate the acute effects of elevated ICP on the posterior eye and optic nerve sheath. We used a finite element (FE) analysis approach to understand the response of the lamina cribrosa and optic nerve to the elevations in ICP thought to occur in microgravity and to identify which tissue components have the greatest impact on strain experienced by optic nerve head tissues.

  11. The cosmological constant in theories with finite spacetime

    International Nuclear Information System (INIS)

    Kummer, Janis

    2014-08-01

    We study the role of the cosmological constant in different theories with finite spacetime. The cosmological constant appears both as an initial condition and as a constant of integration. In the context of the cosmological constant problem a new model will be presented. This modification of general relativity generates a small, non-vanishing cosmological constant, which is radiatively stable. The dynamics of the expansion of the universe in this model will be analyzed. Eventually, we try to solve the emergent problems concerning the generation of accelerated expansion using a quintessence model of dark energy.

  12. Topological terms induced by finite temperature and density fluctuations

    International Nuclear Information System (INIS)

    Niemi, A.J.; Department of Physics, The Ohio State University, Columbus, Ohio 43210)

    1986-01-01

    In (3+1)-dimensional finite-temperature and -density SU(2) gauge theories with left-handed fermions, the three-dimensional Chern-Simons term (topological mass) can be induced by radiative corrections. This result is derived by use of a family's index theorem which also implies that in many other quantum field theories various additional lower-dimensional topological terms can be induced. In the high-temperature limit these terms dominate the partition function, which suggests applications to early-Universe cosmology

  13. Universal hybrid quantum processors

    International Nuclear Information System (INIS)

    Vlasov, A.Yu.

    2003-01-01

    A quantum processor (the programmable gate array) is a quantum network with a fixed structure. A space of states is represented as tensor product of data and program registers. Different unitary operations with the data register correspond to 'loaded' programs without any changing or 'tuning' of the network itself. Due to such property and undesirability of entanglement between program and data registers, universality of quantum processors is a subject of rather strong restrictions. Universal 'stochastic' quantum gate arrays were developed by different authors. It was also proved that 'deterministic' quantum processors with finite-dimensional space of states may be universal only in approximate sense. In the present paper it is shown that, using a hybrid system with continuous and discrete quantum variables, it is possible to suggest a design of strictly universal quantum processors. It is also shown that 'deterministic' limit of specific programmable 'stochastic' U(1) gates (probability of success becomes a unit for the infinite program register), discussed by other authors, may be essentially the same kind of hybrid quantum systems used here

  14. A Finite Model Property for Intersection Types

    Directory of Open Access Journals (Sweden)

    Rick Statman

    2015-03-01

    Full Text Available We show that the relational theory of intersection types known as BCD has the finite model property; that is, BCD is complete for its finite models. Our proof uses rewriting techniques which have as an immediate by-product the polynomial time decidability of the preorder <= (although this also follows from the so called beta soundness of BCD.

  15. Finite-Element Software for Conceptual Design

    DEFF Research Database (Denmark)

    Lindemann, J.; Sandberg, G.; Damkilde, Lars

    2010-01-01

    and research. Forcepad is an effort to provide a conceptual design and teaching tool in a finite-element software package. Forcepad is a two-dimensional finite-element application based on the same conceptual model as image editing applications such as Adobe Photoshop or Microsoft Paint. Instead of using...

  16. Nonlinear finite element modeling of corrugated board

    Science.gov (United States)

    A. C. Gilchrist; J. C. Suhling; T. J. Urbanik

    1999-01-01

    In this research, an investigation on the mechanical behavior of corrugated board has been performed using finite element analysis. Numerical finite element models for corrugated board geometries have been created and executed. Both geometric (large deformation) and material nonlinearities were included in the models. The analyses were performed using the commercial...

  17. Finite Topological Spaces as a Pedagogical Tool

    Science.gov (United States)

    Helmstutler, Randall D.; Higginbottom, Ryan S.

    2012-01-01

    We propose the use of finite topological spaces as examples in a point-set topology class especially suited to help students transition into abstract mathematics. We describe how carefully chosen examples involving finite spaces may be used to reinforce concepts, highlight pathologies, and develop students' non-Euclidean intuition. We end with a…

  18. On p-supersolvability of finite groups

    Indian Academy of Sciences (India)

    [2] Ballester-Bolinches A, Ezquerro L M and Skiba A N, On second maximal subgroups of. Sylow subgroups of finite groups, J. Pure Appl. Algebra 215 (2011) 705–714. [3] Ballester-Bolinches A and Pedraza-Aguilera M C, On minimal subgroups of finite groups,. Acta Math. Hungar. 73 (1996) 335–342. [4] Chen X and Guo W ...

  19. Extracting excited mesons from the finite volume

    Energy Technology Data Exchange (ETDEWEB)

    Doring, Michael [George Washington Univ., Washington, DC (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2014-12-01

    As quark masses come closer to their physical values in lattice simulations, finite volume effects dominate the level spectrum. Methods to extract excited mesons from the finite volume are discussed, like moving frames in the presence of coupled channels. Effective field theory can be used to stabilize the determination of the resonance spectrum.

  20. On the orders of finite semisimple groups

    Indian Academy of Sciences (India)

    Home; Journals; Proceedings – Mathematical Sciences; Volume 115; Issue 4 ... The aim of this paper is to investigate the order coincidences among the finite semisimple groups and to give a reasoning of such order coincidences through the transitive ... We investigate the situation for finite semisimple groups of Lie type.

  1. Interpretability degrees of finitely axiomatized sequential theories

    NARCIS (Netherlands)

    Visser, Albert

    In this paper we show that the degrees of interpretability of finitely axiomatized extensions-in-the-same-language of a finitely axiomatized sequential theory-like Elementary Arithmetic EA, IΣ1, or the Gödel-Bernays theory of sets and classes GB-have suprema. This partially answers a question posed

  2. Interpretability Degrees of Finitely Axiomatized Sequential Theories

    NARCIS (Netherlands)

    Visser, Albert

    2012-01-01

    In this paper we show that the degrees of interpretability of finitely axiomatized extensions-in-the-same-language of a finitely axiomatized sequential theory —like Elementary Arithmetic EA, IΣ1, or the Gödel-Bernays theory of sets and classes GB— have suprema. This partially answers a question

  3. On Finite $J$-Hermitian Quantum Mechanics

    OpenAIRE

    Lee, Sungwook

    2014-01-01

    In his recent paper arXiv:1312.7738, the author discussed $J$-Hermitian quantum mechanics and showed that $PT$-symmetric quantum mechanics is essentially $J$-Hermitian quantum mechanics. In this paper, the author discusses finite $J$-Hermitian quantum mechanics which is derived naturally from its continuum one and its relationship with finite $PT$-symmetric quantum mechanics.

  4. Least-squares finite element methods

    CERN Document Server

    Bochev, Pavel

    2009-01-01

    Since their emergence, finite element methods have taken a place as one of the most versatile and powerful methodologies for the approximate numerical solution of Partial Differential Equations. This book presents the theory and practice of least-square finite element methods, their strengths and weaknesses, successes, and open problems

  5. Pickles and Ice Cream! Food Cravings in Pregnancy: Hypotheses, Preliminary Evidence, and Directions for Future Research

    Directory of Open Access Journals (Sweden)

    Natalia C. Orloff

    2014-09-01

    Full Text Available Women in the United States experience an increase in food cravings at two specific times during their life, 1 perimenstrually and 2 prenatally. The prevalence of excess gestational weight gain (GWG is a growing concern due to its association with adverse health outcomes in both mothers and children. To the extent that prenatal food cravings may be a determinant of energy intake in pregnancy, a better understanding of craving etiology could be crucial in addressing the issue of excessive GWG. This paper reviews the available literature to corroborate and/or dispute some of the most commonly accepted hypotheses regarding the causes of food cravings during pregnancy, including a role of 1 hormonal changes, 2 nutritional deficits, 3 pharmacologically active ingredients in the desired foods, and 4 cultural and psychosocial factors. An existing model of perimenstrual chocolate craving etiology serves to structure the discussion of these hypotheses. The main hypotheses discussed receive little support, with the notable exception of a postulated role of cultural and psychosocial factors. The presence of cravings during pregnancy is a common phenomenon across different cultures, but the types of foods desired and the adverse impact of cravings on health may be culture-specific. Various psychosocial factors appear to correlate with excess GWG, including the presence of restrained eating. Findings strongly suggest that more research be conducted in this area. We propose that future investigations fall into one of the four following categories: 1 validation of food craving and eating-related measures specifically in pregnant populations, 2 use of ecological momentary assessment to obtain real time data on cravings during pregnancy, 3 implementation of longitudinal studies to address causality between eating disorder symptoms, food cravings, and gestational weight gain, and 4 development of interventions to ensure proper prenatal nutrition and prevent excess

  6. Evaluating Hypotheses of Plant Species Invasions on Mediterranean Islands: Inverse Patterns between Alien and Endemic Species

    Directory of Open Access Journals (Sweden)

    Alexander Bjarnason

    2017-08-01

    Full Text Available Invasive alien species cause major changes to ecosystem functioning and patterns of biodiversity, and the main factors involved in invasion success remain contested. Using the Mediterranean island of Crete, Greece as a case study, we suggest a framework for analyzing spatial data of alien species distributions, based on environmental predictors, aiming to gain an understanding of their spatial patterns and spread. Mediterranean islands are under strong ecological pressure from invading species due to their restricted size and increased human impact. Four hypotheses of invasibility, the “propagule pressure hypothesis” (H1, “biotic resistance hypothesis vs. acceptance hypothesis” (H2, “disturbance-mediated hypothesis” (H3, and “environmental heterogeneity hypothesis” (H4 were tested. Using data from alien, native, and endemic vascular plant species, the propagule pressure, biotic resistance vs. acceptance, disturbance-mediated, and environmental heterogeneity hypotheses were tested with Generalized Additive Modeling (GAM of 39 models. Based on model selection, the optimal model includes the positive covariates of native species richness, the negative covariates of endemic species richness, and land area. Variance partitioning between the four hypotheses indicated that the biotic resistance vs. acceptance hypothesis explained the vast majority of the total variance. These results show that areas of high species richness have greater invasibility and support the acceptance hypothesis and “rich-get-richer” distribution of alien species. The negative correlation between alien and endemic species appears to be predominantly driven by altitude, with fewer alien and more endemic species at greater altitudes, and habitat richness. The negative relationship between alien and endemic species richness provides potential for understanding patterns of endemic and alien species on islands, contributing to more effective conservation

  7. Soy-Based Therapeutic Baby Formulas: Testable Hypotheses Regarding the Pros and Cons.

    Science.gov (United States)

    Westmark, Cara J

    2016-01-01

    Soy-based infant formulas have been consumed in the United States since 1909, and currently constitute a significant portion of the infant formula market. There are efforts underway to generate genetically modified soybeans that produce therapeutic agents of interest with the intent to deliver those agents in a soy-based infant formula platform. The threefold purpose of this review article is to first discuss the pros and cons of soy-based infant formulas, then present testable hypotheses to discern the suitability of a soy platform for drug delivery in babies, and finally start a discussion to inform public policy on this important area of infant nutrition.

  8. H-convergence for quasi-linear elliptic equations under natural hypotheses on the correctors

    International Nuclear Information System (INIS)

    Bensoussan, A.; Boccardo, L.; Dall'Aglio, A.; Murat, F.

    1995-01-01

    In this paper we study the behavior of the solutions of quasi-linear Dirichlet problems when the principal parts H-converge and when the lower order terms have quadratic growth with respect to the gradient. We show that the limit problem consists of a principal part which is the H-limit of the principal parts and of the lower order term which is constructed from the corresponding terms by using a linear corrector result. We assume only natural hypotheses on the correctors (i.e. L 2 equi-integrability and not L ∞ boundedness). (author)

  9. Hypotheses regarding the mechanisms of ayahuasca in the treatment of addictions.

    Science.gov (United States)

    Liester, Mitchell B; Prickett, James I

    2012-01-01

    Ayahuasca is a medicinal plant mixture utilized by indigenous peoples throughout the Amazon River basin for healing purposes. The "vine of the soul" or "vine of death," as it is known in South America, contains a combination of monoamine oxidase inhibitors and N,N-dimethyltryptamine (DMT). When ingested together, these medicines produce profound alterations in consciousness. Increasingly, ayahuasca is being utilized to treat addictions. However, the mechanism of action by which ayahuasca treats addictions remains unclear. We offer four hypotheses to explain possible biochemical, physiological, psychological, and transcendent mechanisms by which ayahuasca may exert its anti-addiction effects.

  10. Advances in the phylogenesis of Agaricales and its higher ranks and strategies for establishing phylogenetic hypotheses.

    Science.gov (United States)

    Zhao, Rui-Lin; Desjardin, Dennis E; Soytong, Kasem; Hyde, Kevin D

    2008-10-01

    We present an overview of previous research results on the molecular phylogenetic analyses in Agaricales and its higher ranks (Agaricomycetes/Agaricomycotina/Basidiomycota) along with the most recent treatments of taxonomic systems in these taxa. Establishing phylogenetic hypotheses using DNA sequences, from which an understanding of the natural evolutionary relationships amongst clades may be derived, requires a robust dataset. It has been recognized that single-gene phylogenies may not truly represent organismal phylogenies, but the concordant phylogenetic genealogies from multiple-gene datasets can resolve this problem. The genes commonly used in mushroom phylogenetic research are summarized.

  11. PreBötzinger complex and pacemaker neurons: hypothesized site and kernel for respiratory rhythm generation

    DEFF Research Database (Denmark)

    Rekling, J C; Feldman, J L

    1998-01-01

    Identification of the sites and mechanisms underlying the generation of respiratory rhythm is of longstanding interest to physiologists and neurobiologists. Recently, with the development of novel experimental preparations, especially in vitro en bloc and slice preparations of rodent brainstem......, progress has been made In particular, a site in the ventrolateral medulla, the preBötzinger Complex, is hypothesized to contain neuronal circuits generating respiratory rhythm. Lesions or disruption of synaptic transmission within the preBötzinger Complex, either in vivo or in vitro, can abolish...

  12. Topology optimization using the finite volume method

    DEFF Research Database (Denmark)

    Gersborg-Hansen, Allan; Bendsøe, Martin P.; Sigmund, Ole

    2005-01-01

    Computational procedures for topology optimization of continuum problems using a material distribution method are typically based on the application of the finite element method (FEM) (see, e.g. [1]). In the present work we study a computational framework based on the finite volume method (FVM, s......: the Finite Volume Method. London: Longman Scientific Technical......Computational procedures for topology optimization of continuum problems using a material distribution method are typically based on the application of the finite element method (FEM) (see, e.g. [1]). In the present work we study a computational framework based on the finite volume method (FVM, see......, e.g. [2]) in order to develop methods for topology design for applications where conservation laws are critical such that element--wise conservation in the discretized models has a high priority. This encompasses problems involving for example mass and heat transport. The work described...

  13. Averaging theorems in finite deformation plasticity

    CERN Document Server

    Nemat-Nasser, S C

    1999-01-01

    The transition from micro- to macro-variables of a representative volume element (RVE) of a finitely deformed aggregate (e.g., a composite or a polycrystal) is explored. A number of exact fundamental results on averaging techniques, $9 valid at finite deformations and rotations of any arbitrary heterogeneous continuum, are obtained. These results depend on the choice of suitable kinematic and dynamic variables. For finite deformations, the deformation gradient and $9 its rate, and the nominal stress and its rate, are optimally suited for the averaging purposes. A set of exact identities is presented in terms of these variables. An exact method for homogenization of an ellipsoidal inclusion in an $9 unbounded finitely deformed homogeneous solid is presented, generalizing Eshelby's method for application to finite deformation problems. In terms of the nominal stress rate and the rate of change of the deformation gradient, $9 measured relative to any arbitrary state, a general phase-transformation problem is con...

  14. An introduction to finite tight frames

    CERN Document Server

    Waldron, Shayne F D

    2018-01-01

    This textbook is an introduction to the theory and applications of finite tight frames, an area that has developed rapidly in the last decade. Stimulating much of this growth are the applications of finite frames to diverse fields such as signal processing, quantum information theory, multivariate orthogonal polynomials, and remote sensing. Key features and topics: * First book entirely devoted to finite frames * Extensive exercises and MATLAB examples for classroom use * Important examples, such as harmonic and Heisenberg frames, are presented in preliminary chapters, encouraging readers to explore and develop an intuitive feeling for tight frames * Later chapters delve into general theory details and recent research results * Many illustrations showing the special aspects of the geometry of finite frames * Provides an overview of the field of finite tight frames * Discusses future research directions in the field Featuring exercises and MATLAB examples in each chapter, the book is well suited as a textbook ...

  15. Optimization of finite-size errors in finite-temperature calculations of unordered phases.

    Science.gov (United States)

    Iyer, Deepak; Srednicki, Mark; Rigol, Marcos

    2015-06-01

    It is common knowledge that the microcanonical, canonical, and grand-canonical ensembles are equivalent in thermodynamically large systems. Here, we study finite-size effects in the latter two ensembles. We show that contrary to naive expectations, finite-size errors are exponentially small in grand canonical ensemble calculations of translationally invariant systems in unordered phases at finite temperature. Open boundary conditions and canonical ensemble calculations suffer from finite-size errors that are only polynomially small in the system size. We further show that finite-size effects are generally smallest in numerical linked cluster expansions. Our conclusions are supported by analytical and numerical analyses of classical and quantum systems.

  16. Stochastic delocalization of finite populations

    International Nuclear Information System (INIS)

    Geyrhofer, Lukas; Hallatschek, Oskar

    2013-01-01

    The localization of populations of replicating bacteria, viruses or autocatalytic chemicals arises in various contexts, such as ecology, evolution, medicine or chemistry. Several deterministic mathematical models have been used to characterize the conditions under which localized states can form, and how they break down due to convective driving forces. It has been repeatedly found that populations remain localized unless the bias exceeds a critical threshold value, and that close to the transition the population is characterized by a diverging length scale. These results, however, have been obtained upon ignoring number fluctuations (‘genetic drift’), which are inevitable given the discreteness of the replicating entities. Here, we study the localization/delocalization of a finite population in the presence of genetic drift. The population is modeled by a linear chain of subpopulations, or demes, which exchange migrants at a constant rate. Individuals in one particular deme, called ‘oasis’, receive a growth rate benefit, and the total population is regulated to have constant size N. In this ecological setting, we find that any finite population delocalizes on sufficiently long time scales. Depending on parameters, however, populations may remain localized for a very long time. The typical waiting time to delocalization increases exponentially with both population size and distance to the critical wind speed of the deterministic approximation. We augment these simulation results by a mathematical analysis that treats the reproduction and migration of individuals as branching random walks subject to global constraints. For a particular constraint, different from a fixed population size constraint, this model yields a solvable first moment equation. We find that this solvable model approximates very well the fixed population size model for large populations, but starts to deviate as population sizes are small. Nevertheless, the qualitative behavior of the

  17. What is finiteness? (Abhishek Banerjee) (Indian Institute of Science)

    Indian Academy of Sciences (India)

    Do finites get enough respect? • Finiteness is easy, no? • Just count whether 1, 2, 3,... • But then we miss out on the true richness of the concept of finitness. • There's more finiteness around. In fact, finiteness is what helps us really understand things. 5 ...

  18. New evidence about language and cognitive development based on a longitudinal study: hypotheses for intervention.

    Science.gov (United States)

    Goldin-Meadow, Susan; Levine, Susan C; Hedges, Larry V; Huttenlocher, Janellen; Raudenbush, Stephen W; Small, Steven L

    2014-09-01

    We review findings from a four-year longitudinal study of language learning conducted on two samples: a sample of typically developing children whose parents vary substantially in socioeconomic status, and a sample of children with pre- or perinatal brain injury. This design enables us to study language development across a wide range of language learning environments and a wide range of language learners. We videotaped samples of children's and parents' speech and gestures during spontaneous interactions at home every four months, and then we transcribed and coded the tapes. We focused on two behaviors known to vary across individuals and environments-child gesture and parent speech-behaviors that have the potential to index, and perhaps even play a role in creating, differences across children in linguistic and other cognitive skills. Our observations have led to four hypotheses that have promise for the development of diagnostic tools and interventions to enhance language and cognitive development and brain plasticity after neonatal injury. One kind of hypothesis involves tools that could identify children who may be at risk for later language deficits. The other involves interventions that have the potential to promote language development. We present our four hypotheses as a summary of the findings from our study because there is scientific evidence behind them and because this evidence has the potential to be put to practical use in improving education. (c) 2014 APA, all rights reserved.

  19. New Evidence About Language and Cognitive Development Based on a Longitudinal Study: Hypotheses for Intervention

    Science.gov (United States)

    Goldin-Meadow, Susan; Levine, Susan C.; Hedges, Larry V.; Huttenlocher, Janellen; Raudenbush, Stephen W.; Small, Steven L.

    2014-01-01

    We review findings from a four-year longitudinal study of language learning conducted on two samples: a sample of typically developing children whose parents vary substantially in socioeconomic status, and a sample of children with pre- or perinatal brain injury. This design enables us to study language development across a wide range of language learning environments and a wide range of language learners. We videotaped samples of children's and parents' speech and gestures during spontaneous interactions at home every four months, and then we transcribed and coded the tapes. We focused on two behaviors known to vary across individuals and environments—child gesture and parent speech—behaviors that have the potential to index, and perhaps even play a role in creating, differences across children in linguistic and other cognitive skills. Our observations have led to four hypotheses that have promise for the development of diagnostic tools and interventions to enhance language and cognitive development and brain plasticity after neonatal injury. One kind of hypothesis involves tools that could identify children who may be at risk for later language deficits. The other involves interventions that have the potential to promote language development. We present our four hypotheses as a summary of the findings from our study because there is scientific evidence behind them and because this evidence has the potential to be put to practical use in improving education. PMID:24911049

  20. Hypothesized, Directly-Coded Curve Shapes in Growth Curve Analysis: An Example

    Directory of Open Access Journals (Sweden)

    Patricia M. Herman

    2013-02-01

    Full Text Available Growth curve analysis provides important informational benefits regarding intervention outcomes over time. Rarely, however, should outcome trajectories be assumed to be linear. Instead, both the shape and the slope of the growth curve can be estimated. Non-linear growth curves are usually modeled by including either higher-order time variables or orthogonal polynomial contrast codes. Each has limitations (multicollinearity with the first, a lack of coefficient interpretability with the second, and a loss of degrees of freedom with both and neither encourages direct testing of alternative hypothesized curve shapes. Especially in studies with relatively small samples it is likely to be useful to preserve as much information as possible at the individual level. This article presents a step-by-step example of the use and testing of hypothesized curve shapes in the estimation of growth curves using hierarchical linear modeling for a small intervention study. DOI: 10.2458/azu_jmmss.v3i2.16476

  1. Female Swedish backpackers in Vietnam: a hypotheses generating study on sexual health risks while travelling.

    Science.gov (United States)

    Dahlman, Disa; Stafström, Martin

    2013-01-01

    According to previous studies, foreign travellers and backpackers are at increased risk of sexually transmitted infections (STI). Concurrently, STI incidence, especially Chlamydia, is increasing among young Swedes. Our objective was to investigate Swedish backpackers' own view of sexual health and risks while travelling, with the purpose to identify hypotheses for further, more extensive research. In-depth semi-structured interviews were carried out in Vietnam with four Swedish women in their early twenties. The interviewees had been travelling throughout South East Asia for a period of at least two weeks. There were large differences between the respondents regarding perceived health risks in relation to food safety, STI, and alcohol and drug use; and to what extent their behaviour while travelling deviated from their normal one. In contrast, the interviewees shared a perceived lack of knowledge about sexual health abroad. The study identified six hypotheses and suggestions for preventive measures that could be analysed in future research. The study demonstrated that sexual behaviour as well as attitudes and norms were strongly linked to the individual level, rather than to the group of backpackers. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. No evidence for bilingual cognitive advantages: A test of four hypotheses.

    Science.gov (United States)

    von Bastian, Claudia C; Souza, Alessandra S; Gade, Miriam

    2016-02-01

    The question whether being bilingual yields cognitive benefits is highly controversial with prior studies providing inconsistent results. Failures to replicate the bilingual advantage have been attributed to methodological factors such as comparing dichotomous groups and measuring cognitive abilities separately with single tasks. Therefore, the authors evaluated the 4 most prominent hypotheses of bilingual advantages for inhibitory control, conflict monitoring, shifting, and general cognitive performance by assessing bilingualism on 3 continuous dimensions (age of acquisition, proficiency, and usage) in a sample of 118 young adults and relating it to 9 cognitive abilities each measured by multiple tasks. Linear mixed-effects models accounting for multiple sources of variance simultaneously and controlling for parents' education as an index of socioeconomic status revealed no evidence for any of the 4 hypotheses. Hence, the authors' results suggest that bilingual benefits are not as broad and as robust as has been previously claimed. Instead, earlier effects were possibly due to task-specific effects in selective and often small samples. PsycINFO Database Record (c) 2016 APA, all rights reserved.

  3. Race-Ethnicity and Health Trajectories: Tests of Three Hypotheses across Multiple Groups and Health Outcomes

    Science.gov (United States)

    Brown, Tyson H.; O’Rand, Angela M.; Adkins, Daniel E.

    2013-01-01

    Racial-ethnic disparities in static levels of health are well documented. Less is known about racial-ethnic differences in age trajectories of health. The few studies on this topic have examined only single health outcomes and focused on black-white disparities. This study extends prior research by using a life course perspective, panel data from the Health and Retirement Study, and multilevel growth curve models to investigate racial-ethnic differences in the trajectories of serious conditions and functional limitations among blacks, Mexican Americans, and whites. We test three hypotheses on the nature of racial-ethnic disparities in health across the life course (aging-as-leveler, persistent inequality, and cumulative disadvantage). Results controlling for mortality selection reveal that support for the hypotheses varies by health outcome, racial-ethnic group, and life stage. Controlling for childhood socioeconomic status, adult social and economic resources, and health behaviors reduces but does not eliminate racial-ethnic disparities in health trajectories. PMID:22940814

  4. New Vehicle Detection Method with Aspect Ratio Estimation for Hypothesized Windows

    Directory of Open Access Journals (Sweden)

    Jisu Kim

    2015-12-01

    Full Text Available All kinds of vehicles have different ratios of width to height, which are called the aspect ratios. Most previous works, however, use a fixed aspect ratio for vehicle detection (VD. The use of a fixed vehicle aspect ratio for VD degrades the performance. Thus, the estimation of a vehicle aspect ratio is an important part of robust VD. Taking this idea into account, a new on-road vehicle detection system is proposed in this paper. The proposed method estimates the aspect ratio of the hypothesized windows to improve the VD performance. Our proposed method uses an Aggregate Channel Feature (ACF and a support vector machine (SVM to verify the hypothesized windows with the estimated aspect ratio. The contribution of this paper is threefold. First, the estimation of vehicle aspect ratio is inserted between the HG (hypothesis generation and the HV (hypothesis verification. Second, a simple HG method named a signed horizontal edge map is proposed to speed up VD. Third, a new measure is proposed to represent the overlapping ratio between the ground truth and the detection results. This new measure is used to show that the proposed method is better than previous works in terms of robust VD. Finally, the Pittsburgh dataset is used to verify the performance of the proposed method.

  5. The evolution of parental care in insects: A test of current hypotheses

    Science.gov (United States)

    Gilbert, James D J; Manica, Andrea

    2015-01-01

    Which sex should care for offspring is a fundamental question in evolution. Invertebrates, and insects in particular, show some of the most diverse kinds of parental care of all animals, but to date there has been no broad comparative study of the evolution of parental care in this group. Here, we test existing hypotheses of insect parental care evolution using a literature-compiled phylogeny of over 2000 species. To address substantial uncertainty in the insect phylogeny, we use a brute force approach based on multiple random resolutions of uncertain nodes. The main transitions were between no care (the probable ancestral state) and female care. Male care evolved exclusively from no care, supporting models where mating opportunity costs for caring males are reduced—for example, by caring for multiple broods—but rejecting the “enhanced fecundity” hypothesis that male care is favored because it allows females to avoid care costs. Biparental care largely arose by males joining caring females, and was more labile in Holometabola than in Hemimetabola. Insect care evolution most closely resembled amphibian care in general trajectory. Integrating these findings with the wealth of life history and ecological data in insects will allow testing of a rich vein of existing hypotheses. PMID:25825047

  6. Confidence Intervals: From tests of statistical significance to confidence intervals, range hypotheses and substantial effects

    Directory of Open Access Journals (Sweden)

    Dominic Beaulieu-Prévost

    2006-03-01

    Full Text Available For the last 50 years of research in quantitative social sciences, the empirical evaluation of scientific hypotheses has been based on the rejection or not of the null hypothesis. However, more than 300 articles demonstrated that this method was problematic. In summary, null hypothesis testing (NHT is unfalsifiable, its results depend directly on sample size and the null hypothesis is both improbable and not plausible. Consequently, alternatives to NHT such as confidence intervals (CI and measures of effect size are starting to be used in scientific publications. The purpose of this article is, first, to provide the conceptual tools necessary to implement an approach based on confidence intervals, and second, to briefly demonstrate why such an approach is an interesting alternative to an approach based on NHT. As demonstrated in the article, the proposed CI approach avoids most problems related to a NHT approach and can often improve the scientific and contextual relevance of the statistical interpretations by testing range hypotheses instead of a point hypothesis and by defining the minimal value of a substantial effect. The main advantage of such a CI approach is that it replaces the notion of statistical power by an easily interpretable three-value logic (probable presence of a substantial effect, probable absence of a substantial effect and probabilistic undetermination. The demonstration includes a complete example.

  7. Asymptotic Optimality of Combined Double Sequential Weighted Probability Ratio Test for Three Composite Hypotheses

    Directory of Open Access Journals (Sweden)

    Lei Wang

    2015-01-01

    Full Text Available We propose the weighted expected sample size (WESS to evaluate the overall performance on the indifference-zones for three composite hypotheses’ testing problem. Based on minimizing the WESS to control the expected sample sizes, a new sequential test is developed by utilizing two double sequential weighted probability ratio tests (2-SWPRTs simultaneously. It is proven that the proposed test has a finite stopping time and is asymptotically optimal in the sense of asymptotically minimizing not only the expected sample size but also any positive moment of the stopping time on the indifference-zones under some mild conditions. Simulation studies illustrate that the proposed test has the smallest WESS and relative mean index (RMI compared with Sobel-Wald and Whitehead-Brunier tests.

  8. n-th Roots in finite polyhedral and centro-polyhedral groups

    Indian Academy of Sciences (India)

    2Department of Mathematics, Tabriz Branch, Islamic Azad University, Tabriz, Iran. *Corresponding author. E-mail: sadeghieh@iauyazd.ac.ir; kdelir@gmail.com; k_ahmadi@iaut.ac.ir. MS received 25 November 2013; revised 7 July 2014. Abstract. The probability that a randomly chosen element in a non-abelian finite.

  9. On non-Frattini chief factors and solvability of finite groups

    Indian Academy of Sciences (India)

    Indian Acad. Sci. (Math. Sci.) Vol. 122, No. 2, May 2012, pp. 163–173. c Indian Academy of Sciences. On non-Frattini chief factors and solvability of finite groups. JIANJUN LIU1,∗. , XIUYUN GUO2 and QIANLU LI3. 1School of Mathematics and Statistics, Southwest University,. Chongqing 400715, People's Republic of China.

  10. Social exclusion in finite populations

    Science.gov (United States)

    Li, Kun; Cong, Rui; Wu, Te; Wang, Long

    2015-04-01

    Social exclusion, keeping free riders from benefit sharing, plays an important role in sustaining cooperation in our world. Here we propose two different exclusion regimes, namely, peer exclusion and pool exclusion, to investigate the evolution of social exclusion in finite populations. In the peer exclusion regime, each excluder expels all the defectors independently, and thus bears the total cost on his own, while in the pool exclusion regime, excluders spontaneously form an institution to carry out rejection of the free riders, and each excluder shares the cost equally. In a public goods game containing only excluders and defectors, it is found that peer excluders outperform pool excluders if the exclusion costs are small, and the situation is converse once the exclusion costs exceed some critical points, which holds true for all the selection intensities and different update rules. Moreover, excluders can dominate the whole population under a suitable parameters range in the presence of second-order free riders (cooperators), showing that exclusion has prominent advantages over common costly punishment. More importantly, our finding indicates that the group exclusion mechanism helps the cooperative union to survive under unfavorable conditions. Our results may give some insights into better understanding the prevalence of such a strategy in the real world and its significance in sustaining cooperation.

  11. FEBio: finite elements for biomechanics.

    Science.gov (United States)

    Maas, Steve A; Ellis, Benjamin J; Ateshian, Gerard A; Weiss, Jeffrey A

    2012-01-01

    In the field of computational biomechanics, investigators have primarily used commercial software that is neither geared toward biological applications nor sufficiently flexible to follow the latest developments in the field. This lack of a tailored software environment has hampered research progress, as well as dissemination of models and results. To address these issues, we developed the FEBio software suite (http://mrl.sci.utah.edu/software/febio), a nonlinear implicit finite element (FE) framework, designed specifically for analysis in computational solid biomechanics. This paper provides an overview of the theoretical basis of FEBio and its main features. FEBio offers modeling scenarios, constitutive models, and boundary conditions, which are relevant to numerous applications in biomechanics. The open-source FEBio software is written in C++, with particular attention to scalar and parallel performance on modern computer architectures. Software verification is a large part of the development and maintenance of FEBio, and to demonstrate the general approach, the description and results of several problems from the FEBio Verification Suite are presented and compared to analytical solutions or results from other established and verified FE codes. An additional simulation is described that illustrates the application of FEBio to a research problem in biomechanics. Together with the pre- and postprocessing software PREVIEW and POSTVIEW, FEBio provides a tailored solution for research and development in computational biomechanics.

  12. Finite element coiled cochlea model

    Science.gov (United States)

    Isailovic, Velibor; Nikolic, Milica; Milosevic, Zarko; Saveljic, Igor; Nikolic, Dalibor; Radovic, Milos; Filipović, Nenad

    2015-12-01

    Cochlea is important part of the hearing system, and thanks to special structure converts external sound waves into neural impulses which go to the brain. Shape of the cochlea is like snail, so geometry of the cochlea model is complex. The simplified cochlea coiled model was developed using finite element method inside SIFEM FP7 project. Software application is created on the way that user can prescribe set of the parameters for spiral cochlea, as well as material properties and boundary conditions to the model. Several mathematical models were tested. The acoustic wave equation for describing fluid in the cochlea chambers - scala vestibuli and scala timpani, and Newtonian dynamics for describing vibrations of the basilar membrane are used. The mechanical behavior of the coiled cochlea was analyzed and the third chamber, scala media, was not modeled because it does not have a significant impact on the mechanical vibrations of the basilar membrane. The obtained results are in good agreement with experimental measurements. Future work is needed for more realistic geometry model. Coiled model of the cochlea was created and results are compared with initial simplified coiled model of the cochlea.

  13. Stabilized Finite Elements in FUN3D

    Science.gov (United States)

    Anderson, W. Kyle; Newman, James C.; Karman, Steve L.

    2017-01-01

    A Streamlined Upwind Petrov-Galerkin (SUPG) stabilized finite-element discretization has been implemented as a library into the FUN3D unstructured-grid flow solver. Motivation for the selection of this methodology is given, details of the implementation are provided, and the discretization for the interior scheme is verified for linear and quadratic elements by using the method of manufactured solutions. A methodology is also described for capturing shocks, and simulation results are compared to the finite-volume formulation that is currently the primary method employed for routine engineering applications. The finite-element methodology is demonstrated to be more accurate than the finite-volume technology, particularly on tetrahedral meshes where the solutions obtained using the finite-volume scheme can suffer from adverse effects caused by bias in the grid. Although no effort has been made to date to optimize computational efficiency, the finite-element scheme is competitive with the finite-volume scheme in terms of computer time to reach convergence.

  14. Clifford algebra in finite quantum field theories

    International Nuclear Information System (INIS)

    Moser, M.

    1997-12-01

    We consider the most general power counting renormalizable and gauge invariant Lagrangean density L invariant with respect to some non-Abelian, compact, and semisimple gauge group G. The particle content of this quantum field theory consists of gauge vector bosons, real scalar bosons, fermions, and ghost fields. We assume that the ultimate grand unified theory needs no cutoff. This yields so-called finiteness conditions, resulting from the demand for finite physical quantities calculated by the bare Lagrangean. In lower loop order, necessary conditions for finiteness are thus vanishing beta functions for dimensionless couplings. The complexity of the finiteness conditions for a general quantum field theory makes the discussion of non-supersymmetric theories rather cumbersome. Recently, the F = 1 class of finite quantum field theories has been proposed embracing all supersymmetric theories. A special type of F = 1 theories proposed turns out to have Yukawa couplings which are equivalent to generators of a Clifford algebra representation. These algebraic structures are remarkable all the more than in the context of a well-known conjecture which states that finiteness is maybe related to global symmetries (such as supersymmetry) of the Lagrangean density. We can prove that supersymmetric theories can never be of this Clifford-type. It turns out that these Clifford algebra representations found recently are a consequence of certain invariances of the finiteness conditions resulting from a vanishing of the renormalization group β-function for the Yukawa couplings. We are able to exclude almost all such Clifford-like theories. (author)

  15. Attribution of hydrological change using the Method of Multiple Working Hypotheses

    Science.gov (United States)

    Harrigan, Shaun

    2017-04-01

    The methods we have developed for managing our long-term water supply and protection from extreme hydrological events such as droughts and floods have been founded on the assumption that the hydrological cycle operates under natural conditions. However, it increasingly recognised that humans have the potential to induce significant change in almost every component of the hydrological cycle, for example, climate change, land-use change, and river engineering. Statistical detection of change in streamflow, outside that of natural variability, is an important scientific endeavour, but it does not tell us anything about the drivers of change. Attribution is the process of establishing the most likely cause(s) of a detected change - the why. Attribution is complex due to the integrated nature of streamflow and the proliferation of multiple possible drivers. It is perhaps this complexity, combined with few proven theoretical approaches to this problem in hydrology that has led to others to call for "more efforts and scientific rigour" (Merz et al., 2012). It is easier to limit the cause of a detected change to a single driver, or use simple correlation analysis alone as evidence of causation. It is convenient when the direction of a change in streamflow is consistent with what is expected from a well-known driver such as climate change. Over a century ago, Thomas Chamberlin argued these types of issues were common in many disciplines given how the scientific method is approached in general. His 1890 article introduces the Method of Multiple Working Hypotheses (MMWH) in an attempt to limit our confirmation bias and strives for increased objectivity. This presentation will argue that the MMWH offers an attractive theoretical approach to the attribution of hydrological change in modern hydrology as demonstrated through a case study of a well-documented change point in streamflow within the Boyne Catchment in Ireland. Further Reading Chamberlin, T. C.: The Method of Multiple

  16. On the fate of the Standard Model at finite temperature

    Energy Technology Data Exchange (ETDEWEB)

    Rose, Luigi Delle; Marzo, Carlo [Università del Salento, Dipartimento di Matematica e Fisica “Ennio De Giorgi' ,Via Arnesano, 73100 Lecce (Italy); INFN - Sezione di Lecce,via Arnesano, 73100 Lecce (Italy); Urbano, Alfredo [SISSA - International School for Advanced Studies,via Bonomea 256, 34136 Trieste (Italy)

    2016-05-10

    In this paper we revisit and update the computation of thermal corrections to the stability of the electroweak vacuum in the Standard Model. At zero temperature, we make use of the full two-loop effective potential, improved by three-loop beta functions with two-loop matching conditions. At finite temperature, we include one-loop thermal corrections together with resummation of daisy diagrams. We solve numerically — both at zero and finite temperature — the bounce equation, thus providing an accurate description of the thermal tunneling. Assuming a maximum temperature in the early Universe of the order of 10{sup 18} GeV, we find that the instability bound excludes values of the top mass M{sub t}≳173.6 GeV, with M{sub h}≃125 GeV and including uncertainties on the strong coupling. We discuss the validity and temperature-dependence of this bound in the early Universe, with a special focus on the reheating phase after inflation.

  17. Development of working hypotheses linking management of the Missouri River to population dynamics of Scaphirhynchus albus (pallid sturgeon)

    Science.gov (United States)

    Jacobson, Robert B.; Parsley, Michael J.; Annis, Mandy L.; Colvin, Michael E.; Welker, Timothy L.; James, Daniel A.

    2016-01-20

    This report documents a process of filtering of hypotheses that relate Missouri River Scaphirhynchus albus (pallid sturgeon) population dynamics to management actions including flow alterations, channel reconfigurations, and pallid sturgeon population augmentation. The filtering process was a partnership among U.S. Geological Survey, U.S. Army Corps of Engineers, and U.S. Fish and Wildlife Service to contribute to the Missouri River Recovery Management Plan process. The objective of the filtering process was to produce a set of hypotheses with high relevance to pallid sturgeon population dynamics and decision making on the Missouri River. The Missouri River Pallid Sturgeon Effects Analysis team filtered hundreds of potential hypotheses implicit in conceptual ecological models to develop a set of 40 candidate dominant hypotheses that were identified by experts as being important in pallid sturgeon population dynamics. Using a modified Delphi process and additional expert opinion, the team reduced this set of hypotheses to 23 working dominant hypotheses. We then matched the 23 hypotheses with management actions that could influence the biotic outcomes, resulting in as many as 176 potential effects between management actions and pallid sturgeon in the Missouri River. This number was consolidated to a candidate set of 53 working management hypotheses because some management actions applied to multiple life stages of the pallid sturgeon. We used an additional round of expert surveys to identify a set of 30 working management hypotheses. Finally, the set of working management hypotheses was filtered by the U.S. Army Corps of Engineers, Missouri River Recovery Program for actions that were within the agency’s authority and jurisdiction. This round resulted in a set of 21 hypotheses for initial modeling of linkages from management to pallid sturgeon population responses.

  18. Finite Markov processes and their applications

    CERN Document Server

    Iosifescu, Marius

    2007-01-01

    A self-contained treatment of finite Markov chains and processes, this text covers both theory and applications. Author Marius Iosifescu, vice president of the Romanian Academy and director of its Center for Mathematical Statistics, begins with a review of relevant aspects of probability theory and linear algebra. Experienced readers may start with the second chapter, a treatment of fundamental concepts of homogeneous finite Markov chain theory that offers examples of applicable models.The text advances to studies of two basic types of homogeneous finite Markov chains: absorbing and ergodic ch

  19. Finite-dimensional division algebras over fields

    CERN Document Server

    Jacobson, Nathan

    2009-01-01

    Finite-Dimensional Division Algebras over fields determine, by the Wedderburn Theorem, the semi-simple finite-dimensional algebras over a field. They lead to the definition of the Brauer group and to certain geometric objects, the Brauer-Severi varieties. The book concentrates on those algebras that have an involution. Algebras with involution appear in many contexts; they arose first in the study of the so-called 'multiplication algebras of Riemann matrices'. The largest part of the book is the fifth chapter, dealing with involutorial simple algebras of finite dimension over a field. Of parti

  20. Finite element analysis of piezoelectric materials

    International Nuclear Information System (INIS)

    Lowrie, F.; Stewart, M.; Cain, M.; Gee, M.

    1999-01-01

    This guide is intended to help people wanting to do finite element analysis of piezoelectric materials by answering some of the questions that are peculiar to piezoelectric materials. The document is not intended as a complete beginners guide for finite element analysis in general as this is better dealt with by the individual software producers. The guide is based around the commercial package ANSYS as this is a popular package amongst piezoelectric material users, however much of the information will still be useful to users of other finite element codes. (author)

  1. A Note on Powers in Finite Fields

    DEFF Research Database (Denmark)

    Aabrandt, Andreas; Hansen, Vagn Lundsgaard

    2016-01-01

    , system theory, coding theory and cryptology. In this connection it is of interest to know criteria for the existence of squares and other powers in arbitrary finite fields. Making good use of polynomial division in polynomial rings over finite fields, we have examined a classical criterion of Euler...... for squares in odd prime fields, giving it a formulation which is apt for generalization to arbitrary finite fields and powers. Our proof uses algebra rather than classical number theory, which makes it convenient when presenting basic methods of applied algebra in the classroom....

  2. Finite-volume scheme for anisotropic diffusion

    Energy Technology Data Exchange (ETDEWEB)

    Es, Bram van, E-mail: bramiozo@gmail.com [Centrum Wiskunde & Informatica, P.O. Box 94079, 1090GB Amsterdam (Netherlands); FOM Institute DIFFER, Dutch Institute for Fundamental Energy Research, The Netherlands" 1 (Netherlands); Koren, Barry [Eindhoven University of Technology (Netherlands); Blank, Hugo J. de [FOM Institute DIFFER, Dutch Institute for Fundamental Energy Research, The Netherlands" 1 (Netherlands)

    2016-02-01

    In this paper, we apply a special finite-volume scheme, limited to smooth temperature distributions and Cartesian grids, to test the importance of connectivity of the finite volumes. The area of application is nuclear fusion plasma with field line aligned temperature gradients and extreme anisotropy. We apply the scheme to the anisotropic heat-conduction equation, and compare its results with those of existing finite-volume schemes for anisotropic diffusion. Also, we introduce a general model adaptation of the steady diffusion equation for extremely anisotropic diffusion problems with closed field lines.

  3. An introduction to finite projective planes

    CERN Document Server

    Albert, Abraham Adrian

    2015-01-01

    Geared toward both beginning and advanced undergraduate and graduate students, this self-contained treatment offers an elementary approach to finite projective planes. Following a review of the basics of projective geometry, the text examines finite planes, field planes, and coordinates in an arbitrary plane. Additional topics include central collineations and the little Desargues' property, the fundamental theorem, and examples of finite non-Desarguesian planes.Virtually no knowledge or sophistication on the part of the student is assumed, and every algebraic system that arises is defined and

  4. Electrical machine analysis using finite elements

    CERN Document Server

    Bianchi, Nicola

    2005-01-01

    OUTLINE OF ELECTROMAGNETIC FIELDSVector AnalysisElectromagnetic FieldsFundamental Equations SummaryReferencesBASIC PRINCIPLES OF FINITE ELEMENT METHODSIntroductionField Problems with Boundary ConditionsClassical Method for the Field Problem SolutionThe Classical Residual Method (Galerkin's Method)The Classical Variational Method (Rayleigh-Ritz's Method)The Finite Element MethodReferencesAPPLICATIONS OF THE FINITE ELEMENT METHOD TO TWO-DIMENSIONAL FIELDSIntroductionLinear Interpolation of the Function fApplication of the Variational MethodSimple Descriptions of Electromagnetic FieldsAppendix: I

  5. The theory of finitely generated commutative semigroups

    CERN Document Server

    Rédei, L; Stark, M; Gravett, K A H

    1966-01-01

    The Theory of Finitely Generated Commutative Semigroups describes a theory of finitely generated commutative semigroups which is founded essentially on a single """"fundamental theorem"""" and exhibits resemblance in many respects to the algebraic theory of numbers. The theory primarily involves the investigation of the F-congruences (F is the the free semimodule of the rank n, where n is a given natural number). As applications, several important special cases are given. This volume is comprised of five chapters and begins with preliminaries on finitely generated commutative semigroups before

  6. Books and monographs on finite element technology

    Science.gov (United States)

    Noor, A. K.

    1985-01-01

    The present paper proviees a listing of all of the English books and some of the foreign books on finite element technology, taking into account also a list of the conference proceedings devoted solely to finite elements. The references are divided into categories. Attention is given to fundamentals, mathematical foundations, structural and solid mechanics applications, fluid mechanics applications, other applied science and engineering applications, computer implementation and software systems, computational and modeling aspects, special topics, boundary element methods, proceedings of symmposia and conferences on finite element technology, bibliographies, handbooks, and historical accounts.

  7. Science from evaluation: testing hypotheses about differential effects of three youth-focused suicide prevention trainings.

    Science.gov (United States)

    Coleman, Daniel; Del Quest, Aisling

    2015-01-01

    As part of an evaluation component of a youth suicide prevention, a quasi-experimental repeated measures design tested hypotheses about two brief suicide prevention gatekeeper trainings (Question, Persuade, Refer [QPR] and RESPONSE) and one longer suicide intervention skills training (Applied Suicide Intervention Skills Training [ASIST]). All three trainings showed large changes in prevention attitudes and self-efficacy, largely maintained at follow-up. ASIST trainees had large increases in asking at-risk youth about suicide at follow-up. Convergent with other research, modeling and role-play in training are crucial to increased prevention behaviors. Practice and research implications are discussed, including social work roles in suicide prevention and research.

  8. Combining soft decision algorithms and scale-sequential hypotheses pruning for object recognition

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, V.P.; Manolakos, E.S. [Northeastern Univ., Boston, MA (United States)

    1996-12-31

    This paper describes a system that exploits the synergy of Hierarchical Mixture Density (HMD) estimation with multiresolution decomposition based hypothesis pruning to perform efficiently joint segmentation and labeling of partially occluded objects in images. First we present the overall structure of the HMD estimation algorithm in the form of a recurrent neural network which generates the posterior probabilities of the various hypotheses associated with the image. Then in order to reduce the large memory and computation requirement we propose a hypothesis pruning scheme making use of the orthonormal discrete wavelet transform for dimensionality reduction. We provide an intuitive justification for the validity of this scheme and present experimental results and performance analysis on real and synthetic images to verify our claims.

  9. Factors that encourage females to pursue physical science careers: Testing five common hypotheses

    Science.gov (United States)

    Hazari, Zahra; Potvin, Geoff; Lock, Robynne M.; Lung, Florin; Sadler, Philip M.; Sonnert, Gerhard

    2012-03-01

    There are many hypotheses regarding factors that may encourage female students to pursue careers in the physical sciences. Using Propensity Score Matching (PSM) on national data (n=7505) drawn from the Persistence Research in Science and Engineering (PRiSE) project, we test five commonly held beliefs including having a single-sex physics class, having a female physics teacher, having female scientist guest speakers in physics class, discussing the work of women scientists in physics class, and discussing the under-representation of women in physics class. The effect of these experiences is compared for female students who are matched on several factors, including parental education, prior science/math interests, and academic background, thereby controlling for the effect of many confounding variables.

  10. Comments and hypotheses on the mechanism of methane against ischemia/reperfusion injury

    Directory of Open Access Journals (Sweden)

    He Li

    2017-01-01

    Full Text Available As we all know, methane is a kind of fuel. Previous studies have shown that methanogens in the colon can react with carbon dioxide and hydrogen to produce methane. In a recent study, the anti-inflammatory effects of methane were shown in a dog model of small intestinal ischemia/reperfusion. The mechanism of this anti-inflammatory effect needs further investigation. Recently, studies have shown anti-inflammatory, anti-apoptotic and anti-oxidative effects of methane on different organic injuries. According to the results of these studies, we hypothesize that the initial effects of methane are to react with free radicals and enhance expression of antioxidase through forkhead box transcription factor class O pathway. The anti-inflammatory effect is following the anti-oxidative effect, and the anti-apoptotic effect relies on anti-inflammatory and anti-oxidative effects.

  11. What Will Dental Practice Be Like In 2025? Will You Help Dental Hypotheses Find Answers

    Directory of Open Access Journals (Sweden)

    Edward F. Rossomando

    2011-02-01

    Full Text Available As a result of the rapid acceptance of digital dental equipment, the dental office of 2011 looks very different from that of 1900. Despite these changes, the general dentist of 2011 performs almost the same functions as in 1900 namely the restoration of decayed teeth and the replacement of those lost due to disease. In addition to changes in technology, the last few decades of the 20th century ushered in a revolution in biology leading to the development of a genomic basis of dental disease and the development of bio-based diagnostics and therapeutics. In 2011 few if any of these bio-discoveries have changed dental practice but by 2025 we expect they will. In this editorial, Dental Hypotheses asks readers to “hypothesize” on what dental practice will be like in 2025.

  12. How do trees die? A test of the hydraulic failure and carbon starvation hypotheses.

    Science.gov (United States)

    Sevanto, Sanna; McDowell, Nate G; Dickman, L Turin; Pangle, Robert; Pockman, William T

    2014-01-01

    Despite decades of research on plant drought tolerance, the physiological mechanisms by which trees succumb to drought are still under debate. We report results from an experiment designed to separate and test the current leading hypotheses of tree mortality. We show that piñon pine (Pinus edulis) trees can die of both hydraulic failure and carbon starvation, and that during drought, the loss of conductivity and carbohydrate reserves can also co-occur. Hydraulic constraints on plant carbohydrate use determined survival time: turgor loss in the phloem limited access to carbohydrate reserves, but hydraulic control of respiration prolonged survival. Our data also demonstrate that hydraulic failure may be associated with loss of adequate tissue carbohydrate content required for osmoregulation, which then promotes failure to maintain hydraulic integrity. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

  13. Endodontic treatment and hypotheses on an unusual case of dens invaginatus.

    Science.gov (United States)

    Demartis, Paola; Dessì, Cristina; Cotti, Marina; Cotti, Elisabetta

    2009-03-01

    This work describes a case of "dens invaginatus" and analyzes the possible aspects of this malformation. An unusual type of dens invaginatus was detected in a young patient corresponding to the maxillary lateral incisor and showing extensive periradicular radiolucency and a vestibular fistula. The radiographic and tomographic examination revealed two apices: one wide open in the distal part of the root and the other normally formed in the mesial. Nonsurgical endodontic treatment was performed by using the "one-step apexification technique," filling both apexes with mineral trioxide aggregate followed by composite resin. The follow-up examination 6 months later showed the healing of the radiolucent area and the healing of the sinus tract. Hypotheses on which was the type of dens invaginatus we had to deal with are formulated.

  14. On the particular vulnerability of face recognition to aging: A review of three hypotheses

    Directory of Open Access Journals (Sweden)

    Isabelle eBoutet

    2015-08-01

    Full Text Available Age-related face recognition deficits are characterized by high false alarms to unfamiliar faces, are not as pronounced for other complex stimuli, and are only partially related to general age-related impairments in cognition. This paper reviews some of the underlying processes likely to be implicated in theses deficits by focusing on areas where contradictions abound as a means to highlight avenues for future research. Research pertaining to three following hypotheses is presented: (i perceptual deterioration, (ii encoding of configural information, and (iii difficulties in recollecting contextual information. The evidence surveyed provides support for the idea that all three factors are likely to contribute, under certain conditions, to the deficits in face recognition seen in older adults. We discuss how these different factors might interact in the context of a generic framework of the different stages implicated in face recognition. Several suggestions for future investigations are outlined.

  15. Attachment and parental divorce: a test of the diffusion and sensitive period hypotheses.

    Science.gov (United States)

    Fraley, R Chris; Heffernan, Marie E

    2013-09-01

    One of the assumptions of attachment theory is that disruptions in parental relationships are prospectively related to insecure attachment patterns in adulthood. The majority of research that has evaluated this hypothesis, however, has been based on retrospective reports of the quality of relationships with parents-research that is subject to retrospective biases. In the present research, the authors examined the impact of parental divorce-an event that can be assessed relatively objectively-on attachment patterns in adulthood across two samples. The data indicate that parental divorce has selective rather than diffuse implications for insecure attachment. Namely, parental divorce was more strongly related to insecure relationships with parents in adulthood than insecure relationships with romantic partners or friends. In addition, parental insecurity was most pronounced when parental divorce took place in early childhood. This finding is consistent with hypotheses about sensitive periods in attachment development.

  16. Mindfulness-based treatment to prevent addictive behavior relapse: theoretical models and hypothesized mechanisms of change.

    Science.gov (United States)

    Witkiewitz, Katie; Bowen, Sarah; Harrop, Erin N; Douglas, Haley; Enkema, Matthew; Sedgwick, Carly

    2014-04-01

    Mindfulness-based treatments are growing in popularity among addiction treatment providers, and several studies suggest the efficacy of incorporating mindfulness practices into the treatment of addiction, including the treatment of substance use disorders and behavioral addictions (i.e., gambling). The current paper provides a review of theoretical models of mindfulness in the treatment of addiction and several hypothesized mechanisms of change. We provide an overview of mindfulness-based relapse prevention (MBRP), including session content, treatment targets, and client feedback from participants who have received MBRP in the context of empirical studies. Future research directions regarding operationalization and measurement, identifying factors that moderate treatment effects, and protocol adaptations for specific populations are discussed.

  17. Can manipulations of cognitive load be used to test evolutionary hypotheses?

    Science.gov (United States)

    Barrett, H Clark; Frederick, David A; Haselton, Martie G; Kurzban, Robert

    2006-09-01

    D. DeSteno, M. Y. Bartlett, J. Braverman, and P. Salovey proposed that if sex-differentiated responses to infidelity are evolved, then they should be automatic, and therefore cognitive load should not attenuate them. DeSteno et al. found smaller sex differences in response to sexual versus emotional infidelity among participants under cognitive load, an effect interpreted as evidence against the evolutionary hypothesis. This logic is faulty. Cognitive load probably affects mechanisms involved in simulating infidelity experiences, thus seriously challenging the usefulness of cognitive load manipulations in testing hypotheses involving simulation. The method also entails the assumption that evolved jealousy mechanisms are necessarily automatic, an assumption not supported by theory or evidence. Regardless of how the jealousy debate is eventually settled, cognitive load manipulations cannot rule out the operation of evolved mechanisms. ((c) 2006 APA, all rights reserved).

  18. Phylogeny and classification of the trapdoor spider genus Myrmekiaphila: an integrative approach to evaluating taxonomic hypotheses.

    Science.gov (United States)

    Bailey, Ashley L; Brewer, Michael S; Hendrixson, Brent E; Bond, Jason E

    2010-09-14

    Revised by Bond and Platnick in 2007, the trapdoor spider genus Myrmekiaphila comprises 11 species. Species delimitation and placement within one of three species groups was based on modifications of the male copulatory device. Because a phylogeny of the group was not available these species groups might not represent monophyletic lineages; species definitions likewise were untested hypotheses. The purpose of this study is to reconstruct the phylogeny of Myrmekiaphila species using molecular data to formally test the delimitation of species and species-groups. We seek to refine a set of established systematic hypotheses by integrating across molecular and morphological data sets. Phylogenetic analyses comprising Bayesian searches were conducted for a mtDNA matrix composed of contiguous 12S rRNA, tRNA-val, and 16S rRNA genes and a nuclear DNA matrix comprising the glutamyl and prolyl tRNA synthetase gene each consisting of 1348 and 481 bp, respectively. Separate analyses of the mitochondrial and nuclear genome data and a concatenated data set yield M. torreya and M. millerae paraphyletic with respect to M. coreyi and M. howelli and polyphyletic fluviatilis and foliata species groups. Despite the perception that molecular data present a solution to a crisis in taxonomy, studies like this demonstrate the efficacy of an approach that considers data from multiple sources. A DNA barcoding approach during the species discovery process would fail to recognize at least two species (M. coreyi and M. howelli) whereas a combined approach more accurately assesses species diversity and illuminates speciation pattern and process. Concomitantly these data also demonstrate that morphological characters likewise fail in their ability to recover monophyletic species groups and result in an unnatural classification. Optimizations of these characters demonstrate a pattern of "Dollo evolution" wherein a complex character evolves only once but is lost multiple times throughout the group

  19. [Co-occurrence of anxiety and autism. The social error and allostatic load hypotheses].

    Science.gov (United States)

    Paula-Perez, Isabel

    2013-02-22

    INTRODUCTION. The concept of comorbidity in neurodevelopmental disorders like autism is sometimes ambiguous. The co-occurrence of anxiety and autism is clinically significant, yet it is not always easy to determine whether it is a 'real' comorbidity, where the two comorbid conditions are phenotypically and aetiologically identical to what that anxiety would mean in persons with a neurotypical development, whether it is an anxiety that has been phenotypically modified by the pathological processes of the autism spectrum disorders, thus resulting in a specific variant of these latter, or whether we are dealing with a false comorbidity resulting from rather inaccurate differential diagnoses. DEVELOPMENT. The article puts forward two hypotheses to explain this co-occurrence, which provide each other with feedback and are little more than our reflections on the scientific evidence we have available today, but expressed aloud. The first is the 'social error' hypothesis, which considers that the maladjustments in the social behaviour of persons with autism (which arises from alterations affecting the processes involved in social cognition) help to aggravate anxiety in autism. The second hypothesis, referring to allostatic load, holds that anxiety is a response to chronic stress, wear or exhaustion that is produced by the hyperactivation of certain structures in the limbic system. CONCLUSIONS. The prototypical manifestations of anxiety present in the person with autism are not always related with the same biopsychosocial variables as those observed in persons without autism. Evidence points to hyper-reactive flee-or-fight responses (hypervigilance) when the person finds him or herself outside their comfort zone, and supports the hypotheses of 'social error' and of decompensation of the allostatic mechanism that makes it possible to cope with stress.

  20. Sin nombre virus and rodent species diversity: a test of the dilution and amplification hypotheses.

    Science.gov (United States)

    Clay, Christine A; Lehmer, Erin M; Jeor, Stephen St; Dearing, M Denise

    2009-07-31

    Species diversity is proposed to greatly impact the prevalence of pathogens. Two predominant hypotheses, the "Dilution Effect" and the "Amplification Effect", predict divergent outcomes with respect to the impact of species diversity. The Dilution Effect predicts that pathogen prevalence will be negatively correlated with increased species diversity, while the Amplification Effect predicts that pathogen prevalence will be positively correlated with diversity. For many host-pathogen systems, the relationship between diversity and pathogen prevalence has not be empirically examined. We tested the Dilution and Amplification Effect hypotheses by examining the prevalence of Sin Nombre virus (SNV) with respect to diversity of the nocturnal rodent community. SNV is directly transmitted primarily between deer mice (Peromyscus maniculatus). Using mark-recapture sampling in the Spring and Fall of 2003-2005, we measured SNV prevalence in deer mice at 16 landscape level sites (3.1 hectares each) that varied in rodent species diversity. We explored several mechanisms by which species diversity may affect SNV prevalence, including reduced host density, reduced host persistence, the presence of secondary reservoirs and community composition. We found a negative relationship between species diversity and SNV prevalence in deer mice, thereby supporting the Dilution Effect hypothesis. Deer mouse density and persistence were lower at sites with greater species diversity; however, only deer mouse persistence was positively correlated with SNV prevalence. Pinyon mice (P. truei) may serve as dilution agents, having a negative effect on prevalence, while kangaroo rats (Dipodomys ordii), may have a positive effect on the prevalence of SNV, perhaps through effects on deer mouse behavior. While previous studies on host-pathogen systems have found patterns of diversity consistent with either the Dilution or Amplification Effects, the mechanisms by which species diversity influences

  1. Incentivizing Blood Donation: Systematic Review and Meta-Analysis to Test Titmuss’ Hypotheses

    Science.gov (United States)

    2013-01-01

    Objectives: Titmuss hypothesized that paying blood donors would reduce the quality of the blood donated and would be economically inefficient. We report here the first systematic review to test these hypotheses, reporting on both financial and nonfinancial incentives. Method: Studies deemed eligible for inclusion were peer-reviewed, experimental studies that presented data on the quantity (as a proxy for efficiency) and quality of blood donated in at least two groups: those donating blood when offered an incentive, and those donating blood with no offer of an incentive. The following were searched: MEDLINE, EMBASE and PsycINFO using OVID SP, CINAHL via EBSCO and CENTRAL, the Cochrane Library, Econlit via EBSCO, JSTOR Health and General Science Collection, and Google. Results: The initial search yielded 1100 abstracts, which resulted in 89 full papers being assessed for eligibility, of which seven studies, reported in six papers, met the inclusion criteria. The included studies involved 93,328 participants. Incentives had no impact on the likelihood of donation (OR = 1.22 CI 95% 0.91–1.63; p = .19). There was no difference between financial and nonfinancial incentives in the quantity of blood donated. Of the two studies that assessed quality of blood, one found no effect and the other found an adverse effect from the offer of a free cholesterol test (β = 0.011 p < .05). Conclusion: The limited evidence suggests that Titmuss’ hypothesis of the economic inefficiency of incentives is correct. There is insufficient evidence to assess their likely impact on the quality of the blood provided. PMID:24001244

  2. Incentivizing blood donation: systematic review and meta-analysis to test Titmuss' hypotheses.

    Science.gov (United States)

    Niza, Claudia; Tung, Burcu; Marteau, Theresa M

    2013-09-01

    Titmuss hypothesized that paying blood donors would reduce the quality of the blood donated and would be economically inefficient. We report here the first systematic review to test these hypotheses, reporting on both financial and nonfinancial incentives. Studies deemed eligible for inclusion were peer-reviewed, experimental studies that presented data on the quantity (as a proxy for efficiency) and quality of blood donated in at least two groups: those donating blood when offered an incentive, and those donating blood with no offer of an incentive. The following were searched: MEDLINE, EMBASE and PsycINFO using OVID SP, CINAHL via EBSCO and CENTRAL, the Cochrane Library, Econlit via EBSCO, JSTOR Health and General Science Collection, and Google. The initial search yielded 1100 abstracts, which resulted in 89 full papers being assessed for eligibility, of which seven studies, reported in six papers, met the inclusion criteria. The included studies involved 93,328 participants. Incentives had no impact on the likelihood of donation (OR = 1.22 CI 95% 0.91-1.63; p = .19). There was no difference between financial and nonfinancial incentives in the quantity of blood donated. Of the two studies that assessed quality of blood, one found no effect and the other found an adverse effect from the offer of a free cholesterol test (β = 0.011 p < .05). The limited evidence suggests that Titmuss' hypothesis of the economic inefficiency of incentives is correct. There is insufficient evidence to assess their likely impact on the quality of the blood provided. PsycINFO Database Record (c) 2013 APA, all rights reserved.

  3. Environmental effects on vertebrate species richness: testing the energy, environmental stability and habitat heterogeneity hypotheses.

    Directory of Open Access Journals (Sweden)

    Zhenhua Luo

    Full Text Available BACKGROUND: Explaining species richness patterns is a central issue in biogeography and macroecology. Several hypotheses have been proposed to explain the mechanisms driving biodiversity patterns, but the causes of species richness gradients remain unclear. In this study, we aimed to explain the impacts of energy, environmental stability, and habitat heterogeneity factors on variation of vertebrate species richness (VSR, based on the VSR pattern in China, so as to test the energy hypothesis, the environmental stability hypothesis, and the habitat heterogeneity hypothesis. METHODOLOGY/PRINCIPAL FINDINGS: A dataset was compiled containing the distributions of 2,665 vertebrate species and eleven ecogeographic predictive variables in China. We grouped these variables into categories of energy, environmental stability, and habitat heterogeneity and transformed the data into 100 × 100 km quadrat systems. To test the three hypotheses, AIC-based model selection was carried out between VSR and the variables in each group and correlation analyses were conducted. There was a decreasing VSR gradient from the southeast to the northwest of China. Our results showed that energy explained 67.6% of the VSR variation, with the annual mean temperature as the main factor, which was followed by annual precipitation and NDVI. Environmental stability factors explained 69.1% of the VSR variation and both temperature annual range and precipitation seasonality had important contributions. By contrast, habitat heterogeneity variables explained only 26.3% of the VSR variation. Significantly positive correlations were detected among VSR, annual mean temperature, annual precipitation, and NDVI, whereas the relationship of VSR and temperature annual range was strongly negative. In addition, other variables showed moderate or ambiguous relations to VSR. CONCLUSIONS/SIGNIFICANCE: The energy hypothesis and the environmental stability hypothesis were supported, whereas little

  4. Testing phylogenetic hypotheses of the subgenera of the freshwater crayfish genus Cambarus (Decapoda: Cambaridae.

    Directory of Open Access Journals (Sweden)

    Jesse W Breinholt

    Full Text Available The genus Cambarus is one of three most species rich crayfish genera in the Northern Hemisphere. The genus has its center of diversity in the Southern Appalachians of the United States and has been divided into 12 subgenera. Using Cambarus we test the correspondence of subgeneric designations based on morphology used in traditional crayfish taxonomy to the underlying evolutionary history for these crayfish. We further test for significant correlation and explanatory power of geographic distance, taxonomic model, and a habitat model to estimated phylogenetic distance with multiple variable regression.We use three mitochondrial and one nuclear gene regions to estimate the phylogenetic relationships for species within the genus Cambarus and test evolutionary hypotheses of relationships and associated morphological and biogeographical hypotheses. Our resulting phylogeny indicates that the genus Cambarus is polyphyletic, however we fail to reject the monophyly of Cambarus with a topology test. The majority of the Cambarus subgenera are rejected as monophyletic, suggesting the morphological characters used to define those taxa are subject to convergent evolution. While we found incongruence between taxonomy and estimated phylogenetic relationships, a multiple model regression analysis indicates that taxonomy had more explanatory power of genetic relationships than either habitat or geographic distance.We find convergent evolution has impacted the morphological features used to delimit Cambarus subgenera. Studies of the crayfish genus Orconectes have shown gonopod morphology used to delimit subgenera is also affected by convergent evolution. This suggests that morphological diagnoses based on traditional crayfish taxonomy might be confounded by convergent evolution across the cambarids and has little utility in diagnosing relationships or defining natural groups. We further suggest that convergent morphological evolution appears to be a common

  5. Finite element methods a practical guide

    CERN Document Server

    Whiteley, Jonathan

    2017-01-01

    This book presents practical applications of the finite element method to general differential equations. The underlying strategy of deriving the finite element solution is introduced using linear ordinary differential equations, thus allowing the basic concepts of the finite element solution to be introduced without being obscured by the additional mathematical detail required when applying this technique to partial differential equations. The author generalizes the presented approach to partial differential equations which include nonlinearities. The book also includes variations of the finite element method such as different classes of meshes and basic functions. Practical application of the theory is emphasised, with development of all concepts leading ultimately to a description of their computational implementation illustrated using Matlab functions. The target audience primarily comprises applied researchers and practitioners in engineering, but the book may also be beneficial for graduate students.

  6. A finite element solution of transonic flow

    Science.gov (United States)

    Tatum, K. E.

    1978-01-01

    The use of finite elements is explored in a field in which its use has previously not been deemed very feasible, that of transonic flow. The specific problem chosen is that of steady small-disturbance transonic flow. The nonlinear equations are formulated with an artificial viscosity term added to yield the proper domain of dependence and directional bias in supersonic regions and across imbedded shock waves. Justification is given for the problem and means of solution chosen, and the potential advantages of the finite element procedure over standard finite difference procedures are discussed. Several possible improvements on the method as presently derived are stated. Computational mesh requirements and certain mesh variations are described. Some results equivalent to finite difference calculations are given as a sample solution.

  7. Advanced finite element method in structural engineering

    CERN Document Server

    Long, Yu-Qiu; Long, Zhi-Fei

    2009-01-01

    This book systematically introduces the research work on the Finite Element Method completed over the past 25 years. Original theoretical achievements and their applications in the fields of structural engineering and computational mechanics are discussed.

  8. Multigrid methods for mortar finite elements

    OpenAIRE

    Wohlmuth, Barbara

    2000-01-01

    Multigrid methods for mortar finite elements / R. Krause ; B. Wohlmuth. - In: Multigrid methods VI / Erik Dick ... (ed.). - Berlin u.a. : Springer, 2000. - S. 136-142 (Lecture notes in computational science and engineering ; 14)

  9. Jauch-Piron logics with finiteness conditions

    Science.gov (United States)

    Rogalewicz, Vladimír

    1991-04-01

    We show that there are no non-Boolean block-finite orthomodular posets possessing a unital set of Jauch-Piron states. Thus, an orthomodular poset representing a quantum physical system must have infinitely many blocks.

  10. Finite Volumes for Complex Applications VII

    CERN Document Server

    Ohlberger, Mario; Rohde, Christian

    2014-01-01

    The methods considered in the 7th conference on "Finite Volumes for Complex Applications" (Berlin, June 2014) have properties which offer distinct advantages for a number of applications. The second volume of the proceedings covers reviewed contributions reporting successful applications in the fields of fluid dynamics, magnetohydrodynamics, structural analysis, nuclear physics, semiconductor theory and other topics. The finite volume method in its various forms is a space discretization technique for partial differential equations based on the fundamental physical principle of conservation. Recent decades have brought significant success in the theoretical understanding of the method. Many finite volume methods preserve further qualitative or asymptotic properties, including maximum principles, dissipativity, monotone decay of free energy, and asymptotic stability. Due to these properties, finite volume methods belong to the wider class of compatible discretization methods, which preserve qualitative propert...

  11. Deterministic equation solving over finite fields

    NARCIS (Netherlands)

    Woestijne, Christiaan Evert van de

    2006-01-01

    It is shown how to solve diagonal forms in many variables over finite fields by means of a deterministic efficient algorithm. Applications to norm equations, quadratic forms, and elliptic curves are given.

  12. Gravity-induced stresses in finite slopes

    Science.gov (United States)

    Savage, W.Z.

    1994-01-01

    An exact solution for gravity-induced stresses in finite elastic slopes is presented. This solution, which is applied for gravity-induced stresses in 15, 30, 45 and 90?? finite slopes, has application in pit-slope design, compares favorably with published finite element results for this problem and satisfies the conditions that shear and normal stresses vanish on the ground surface. The solution predicts that horizontal stresses are compressive along the top of the slopes (zero in the case of the 90?? slope) and tensile away from the bottom of the slopes, effects which are caused by downward movement and near-surface horizontal extension in front of the slope in response to gravity loading caused by the additional material associated with the finite slope. ?? 1994.

  13. Super-renormalizable and finite gravitational theories

    Directory of Open Access Journals (Sweden)

    Leonardo Modesto

    2014-12-01

    Full Text Available We hereby introduce and extensively study a class of non-polynomial higher derivative theories of gravity that realize a ultraviolet (UV completion of Einstein general relativity. These theories are unitary (ghost free and at most only one-loop divergences survive. The outcome is a class of theories super-renormalizable in even dimension and finite in odd dimension. Moreover, we explicitly prove in D=4 that there exists an extension of the theory that is completely finite and all the beta functions vanish even at one-loop. These results can be easily extended in extra dimensions and it is likely that the higher dimensional theory can be made finite, too. Therefore we have the possibility for “finite quantum gravity” in any dimension.

  14. FINITE ELEMENT MODEL FOR PREDICTING RESIDUAL ...

    African Journals Online (AJOL)

    direction (σx) had a maximum value of 375MPa (tensile) and minimum value of ... These results shows that the residual stresses obtained by prediction from the finite element method are in fair agreement with the experimental results.

  15. Discrete mechanics Based on Finite Element Methods

    OpenAIRE

    Chen, Jing-bo; Guo, Han-Ying; Wu, Ke

    2002-01-01

    Discrete Mechanics based on finite element methods is presented in this paper. We also explore the relationship between this discrete mechanics and Veselov discrete mechanics. High order discretizations are constructed in terms of high order interpolations.

  16. Critical-Point Structure in Finite Nuclei

    International Nuclear Information System (INIS)

    Leviatan, A.

    2006-01-01

    Properties of quantum shape-phase transitions in finite nuclei are considered in the framework of the interacting boson model. Special emphasis is paid to the dynamics at the critical-point of a general first-order phase transition

  17. Quantiles for Finite Mixtures of Normal Distributions

    Science.gov (United States)

    Rahman, Mezbahur; Rahman, Rumanur; Pearson, Larry M.

    2006-01-01

    Quantiles for finite mixtures of normal distributions are computed. The difference between a linear combination of independent normal random variables and a linear combination of independent normal densities is emphasized. (Contains 3 tables and 1 figure.)

  18. ANSYS mechanical APDL for finite element analysis

    CERN Document Server

    Thompson, Mary Kathryn

    2017-01-01

    ANSYS Mechanical APDL for Finite Element Analysis provides a hands-on introduction to engineering analysis using one of the most powerful commercial general purposes finite element programs on the market. Students will find a practical and integrated approach that combines finite element theory with best practices for developing, verifying, validating and interpreting the results of finite element models, while engineering professionals will appreciate the deep insight presented on the program's structure and behavior. Additional topics covered include an introduction to commands, input files, batch processing, and other advanced features in ANSYS. The book is written in a lecture/lab style, and each topic is supported by examples, exercises and suggestions for additional readings in the program documentation. Exercises gradually increase in difficulty and complexity, helping readers quickly gain confidence to independently use the program. This provides a solid foundation on which to build, preparing readers...

  19. Mean field canonical treatments at finite temperature

    International Nuclear Information System (INIS)

    Rossignoli, R.

    1990-01-01

    A method is proposed to make mean field and higher order canonical treatments at finite temperature. Definite improvements are made over the usual Hartree-Fock thermal (great canonical) treatment. (Author). 10 refs., 3 figs

  20. Finite elements in CAD and ADINA

    International Nuclear Information System (INIS)

    Bathe, K.J.

    1986-01-01

    The use of finite element methods in computer-aided-design - CAD - is discussed. Some current capabilities are presented and important future developments are outlined. The discussion focusses on the use of the ADINA program in CAD applications. (orig.)

  1. Overseas Universities.

    Science.gov (United States)

    Inter-University Council for Higher Education Overseas, London (England).

    The following articles and reports are presented in this publication of "Overseas Universities:""Appropriate Technology and University Education," by John Twidell; "The Training of Engineering Staff for Higher Education Institutions in Developing Countries," by D. W. Daniel, C. A. Leal, J. H. Maynes and T. Wilmore;…

  2. The finite-difference and finite-element modeling of seismic wave propagation and earthquake motion

    International Nuclear Information System (INIS)

    Moszo, P.; Kristek, J.; Galis, M.; Pazak, P.; Balazovijech, M.

    2006-01-01

    Numerical modeling of seismic wave propagation and earthquake motion is an irreplaceable tool in investigation of the Earth's structure, processes in the Earth, and particularly earthquake phenomena. Among various numerical methods, the finite-difference method is the dominant method in the modeling of earthquake motion. Moreover, it is becoming more important in the seismic exploration and structural modeling. At the same time we are convinced that the best time of the finite-difference method in seismology is in the future. This monograph provides tutorial and detailed introduction to the application of the finite-difference, finite-element, and hybrid finite-difference-finite-element methods to the modeling of seismic wave propagation and earthquake motion. The text does not cover all topics and aspects of the methods. We focus on those to which we have contributed. (Author)

  3. Finite element approximation of the Isaacs equation

    OpenAIRE

    Salgado, Abner J.; Zhang, Wujun

    2015-01-01

    We propose and analyze a two-scale finite element method for the Isaacs equation. The fine scale is given by the mesh size $h$ whereas the coarse scale $\\varepsilon$ is dictated by an integro-differential approximation of the partial differential equation. We show that the method satisfies the discrete maximum principle provided that the mesh is weakly acute. This, in conjunction with weak operator consistency of the finite element method, allows us to establish convergence of the numerical s...

  4. Finite Element Model of Gear Induction Hardening

    OpenAIRE

    Hodek, J; Zemko, M; Shykula, P

    2015-01-01

    International audience; This paper presents a finite element model of a gear induction hardening process. The gear was surface-heated by an induction coil and quickly cooled by spraying water. The finite element model was developed as a three-dimensional model. The electromagnetic field, temperature field, stress distribution and microstructure distribution were examined. Temperature and microstructural characteristics were measured and used. The gear material data was obtained in part by mea...

  5. Generators for finite depth subfactor planar algebras

    Indian Academy of Sciences (India)

    The main result of Kodiyalam and Tupurani [3] shows that a subfactor planar algebra of finite depth is singly generated with a finite presentation. If P is a subfactor planar algebra of depth k, it is shown there that a single 2k-box generates P. It is natural to ask what the smallest s is such that a single s-box generates P. While ...

  6. The finite element method in electromagnetics

    CERN Document Server

    Jin, Jianming

    2014-01-01

    A new edition of the leading textbook on the finite element method, incorporating major advancements and further applications in the field of electromagnetics The finite element method (FEM) is a powerful simulation technique used to solve boundary-value problems in a variety of engineering circumstances. It has been widely used for analysis of electromagnetic fields in antennas, radar scattering, RF and microwave engineering, high-speed/high-frequency circuits, wireless communication, electromagnetic compatibility, photonics, remote sensing, biomedical engineering, and space exploration. The

  7. Finite Optimal Stopping Problems: The Seller's Perspective

    Science.gov (United States)

    Hemmati, Mehdi; Smith, J. Cole

    2011-01-01

    We consider a version of an optimal stopping problem, in which a customer is presented with a finite set of items, one by one. The customer is aware of the number of items in the finite set and the minimum and maximum possible value of each item, and must purchase exactly one item. When an item is presented to the customer, she or he observes its…

  8. Surgery simulation using fast finite elements

    DEFF Research Database (Denmark)

    Bro-Nielsen, Morten

    1996-01-01

    This paper describes our recent work on real-time surgery simulation using fast finite element models of linear elasticity. In addition, we discuss various improvements in terms of speed and realism......This paper describes our recent work on real-time surgery simulation using fast finite element models of linear elasticity. In addition, we discuss various improvements in terms of speed and realism...

  9. Thomas Fermi model of finite nuclei

    International Nuclear Information System (INIS)

    Boguta, J.; Rafelski, J.

    1977-01-01

    A relativistic Thomas-Fermi model of finite-nuclei is considered. The effective nuclear interaction is mediated by exchanges of isoscalar scalar and vector mesons. The authors include also a self-interaction of the scalar meson field and the Coulomb repulsion of the protons. The parameters of the model are constrained by the average nuclear properties. The Thomas-Fermi equations are solved numerically for finite, stable nuclei. The particular case of 208 82 Pb is considered in more detail. (Auth.)

  10. On finitely strained magnetoelastic solids

    Science.gov (United States)

    Kankanala, Sundeep Venkat

    Magnetorheological elastomers (MREs) are a class of magnetoelastic solids whose mechanical properties can be altered by the application of magnetic fields. MREs, which are particle filled elastomers, have been developed and proposed as unique solutions for a number of engineering applications, such as tunable engine and chassis mounts in automobiles. In this dissertation we present a study of the magnetoelastic coupling in finitely deformable MREs. Two different continuum formulations for these solids are presented: an Eulerian based direct approach using the second law of thermodynamics plus the conservation laws of mechanics and a new, Lagrangian type formulation based on the unconstrained minimization of a potential energy functional. It is shown that both approaches yield the same governing equations and boundary conditions. Following a discussion of general properties of the free energy function of MREs, a particular such function is used to illustrate the magnetoelastic coupling phenomena in a cylinder subjected to traction or torsion under the presence of external magnetic fields. Motivated by the classical magnetoelastic buckling problem, the general theory is then applied to the solution of the stability of a rectangular block subjected to a uniform magnetic field perpendicular to its longitudinal axis. The variational approach employed utilizes an unconstrained energy minimization. The analytical solution for the critical buckling fields for both the anti-symmetric and symmetric modes are obtained for three different constitutive laws. The corresponding result for beams is extracted asymptotically for a special material and the solution is compared to previously published results. The last part of this work delves into the constitutive modeling of MBEs. Uniaxial experiments are conducted to study the effect of particle chain orientation on the magnetostriction and magnetization responses of an MRE for different levels of compressive and tensile

  11. Evolution of microgastropods (Ellobioidea, Carychiidae): integrating taxonomic, phylogenetic and evolutionary hypotheses

    Science.gov (United States)

    2013-01-01

    Background Current biodiversity patterns are considered largely the result of past climatic and tectonic changes. In an integrative approach, we combine taxonomic and phylogenetic hypotheses to analyze temporal and geographic diversification of epigean (Carychium) and subterranean (Zospeum) evolutionary lineages in Carychiidae (Eupulmonata, Ellobioidea). We explicitly test three hypotheses: 1) morphospecies encompass unrecognized evolutionary lineages, 2) limited dispersal results in a close genetic relationship of geographical proximally distributed taxa and 3) major climatic and tectonic events had an impact on lineage diversification within Carychiidae. Results Initial morphospecies assignments were investigated by different molecular delimitation approaches (threshold, ABGD, GMYC and SP). Despite a conservative delimitation strategy, carychiid morphospecies comprise a great number of unrecognized evolutionary lineages. We attribute this phenomenon to historic underestimation of morphological stasis and phenotypic variability amongst lineages. The first molecular phylogenetic hypothesis for the Carychiidae (based on COI, 16S and H3) reveals Carychium and Zospeum to be reciprocally monophyletic. Geographical proximally distributed lineages are often closely related. The temporal diversification of Carychiidae is best described by a constant rate model of diversification. The evolution of Carychiidae is characterized by relatively few (long distance) colonization events. We find support for an Asian origin of Carychium. Zospeum may have arrived in Europe before extant members of Carychium. Distantly related Carychium clades inhabit a wide spectrum of the available bioclimatic niche and demonstrate considerable niche overlap. Conclusions Carychiid taxonomy is in dire need of revision. An inferred wide distribution and variable phenotype suggest underestimated diversity in Zospeum. Several Carychium morphospecies are results of past taxonomic lumping. By collecting

  12. Sexual segregation of forage patch use: Support for the social-factors and predation hypotheses.

    Science.gov (United States)

    Biggerstaff, Michael T; Lashley, Marcus A; Chitwood, M Colter; Moorman, Christopher E; DePerno, Christopher S

    2017-03-01

    Nearly all species of sexually dimorphic ungulates sexually segregate. Several hypotheses have been proposed to explain this phenomenon, including the social-factors hypothesis (SFH) and the predation hypothesis (PH). Interestingly, previous studies have accepted and rejected each hypothesis within and across species but few studies have simultaneously tested both hypotheses in the same population. In August 2011 and 2012 using 7680 photographs taken with camera traps in standardized forage patches, we tested two predictions of the SFH: 1) foraging efficiency of both sexes would decrease when foraging rate in mixed-sex groups relative to single-sex groups, and 2) activity patterns (i.e., the pattern of temporal use of forage patches on a diel scale) of the sexes would decrease in temporal overlap at the forage patch level (i.e., social segregation) compared to the overall temporal overlap of activity patterns of the population. Also, we tested two predictions of the +PH : 1) the relationship between feeding rates of each sex, and 2) temporal activity overlap would change with changing risk level of forage patches as a result of differing risk perception between sexes. In support of the SFH for temporal segregation, when in mixed-sex groups, mature males and all females decreased feeding rate 30% and 10%, respectively; further, the sexes had similar activity patterns overall (94-95% overlap), though temporal overlap was lower in individual forage patches (68-74% overlap). In multi-male mixed sex groups, at least one male exhibited aggressive posture toward females during all foraging bouts suggesting intersex aggression was the cause of the observed decrease in foraging rates. In support of the PH , the sexes adjusted feeding rate differently in response to changing risk level of a forage patch, encouraging spatial segregation; however, the PH was not supported for temporal segregation because temporal activity pattern overlap did not vary as a function of predation

  13. 3D tooth microwear texture analysis in fishes as a test of dietary hypotheses of durophagy

    International Nuclear Information System (INIS)

    Purnell, Mark A; Darras, Laurent P G

    2016-01-01

    An understanding of how extinct animals functioned underpins our understanding of past evolutionary events, including adaptive radiations, and the role of functional innovation and adaptation as drivers of both micro- and macroevolution. Yet analysis of function in extinct animals is fraught with difficulty. Hypotheses that interpret molariform teeth in fishes as evidence of durophagous (shell-crushing) diets provide a good example of the particular problems inherent in the methods of functional morphology. This is because the assumed close coupling of form and function upon which the approach is based is weakened by, among other things, behavioural flexibility and the absence of a clear one to one relationship between structures and functions. Here we show that ISO 25178-2 standard parameters for surface texture, derived from analysis of worn surfaces of molariform teeth of fishes, vary significantly between species that differ in the amount of hard-shelled prey they consume. Two populations of the Sheepshead Seabream (Archosargus probatocephalus) were studied. This fish is not a dietary specialist, and one of the populations is known to consume more vegetation and less hard-shelled prey than the other; this is reflected in significant differences in their microwear textures. The Archosargus populations differ significantly in their microwear from the specialist shell-crusher Anarhichas lupus (the Atlantic Wolffish). Multivariate analysis of these three groups of fishes lends further support to the relationship between diet and tooth microwear, and provides robust validation of the approach. Application of the multivariate models derived from microwear texture in Archosargus and Anarhichas to a third fish species—the cichlid Astatoreochromis alluaudi—successfully separates wild caught fish that ate hard-shelled prey from lab-raised fish that did not. This cross-taxon validation demonstrates that quantitative analysis of tooth microwear texture can

  14. 3D tooth microwear texture analysis in fishes as a test of dietary hypotheses of durophagy

    Science.gov (United States)

    Purnell, Mark A.; Darras, Laurent P. G.

    2016-03-01

    An understanding of how extinct animals functioned underpins our understanding of past evolutionary events, including adaptive radiations, and the role of functional innovation and adaptation as drivers of both micro- and macroevolution. Yet analysis of function in extinct animals is fraught with difficulty. Hypotheses that interpret molariform teeth in fishes as evidence of durophagous (shell-crushing) diets provide a good example of the particular problems inherent in the methods of functional morphology. This is because the assumed close coupling of form and function upon which the approach is based is weakened by, among other things, behavioural flexibility and the absence of a clear one to one relationship between structures and functions. Here we show that ISO 25178-2 standard parameters for surface texture, derived from analysis of worn surfaces of molariform teeth of fishes, vary significantly between species that differ in the amount of hard-shelled prey they consume. Two populations of the Sheepshead Seabream (Archosargus probatocephalus) were studied. This fish is not a dietary specialist, and one of the populations is known to consume more vegetation and less hard-shelled prey than the other; this is reflected in significant differences in their microwear textures. The Archosargus populations differ significantly in their microwear from the specialist shell-crusher Anarhichas lupus (the Atlantic Wolffish). Multivariate analysis of these three groups of fishes lends further support to the relationship between diet and tooth microwear, and provides robust validation of the approach. Application of the multivariate models derived from microwear texture in Archosargus and Anarhichas to a third fish species—the cichlid Astatoreochromis alluaudi—successfully separates wild caught fish that ate hard-shelled prey from lab-raised fish that did not. This cross-taxon validation demonstrates that quantitative analysis of tooth microwear texture can

  15. High-Order Entropy Stable Finite Difference Schemes for Nonlinear Conservation Laws: Finite Domains

    Science.gov (United States)

    Fisher, Travis C.; Carpenter, Mark H.

    2013-01-01

    Developing stable and robust high-order finite difference schemes requires mathematical formalism and appropriate methods of analysis. In this work, nonlinear entropy stability is used to derive provably stable high-order finite difference methods with formal boundary closures for conservation laws. Particular emphasis is placed on the entropy stability of the compressible Navier-Stokes equations. A newly derived entropy stable weighted essentially non-oscillatory finite difference method is used to simulate problems with shocks and a conservative, entropy stable, narrow-stencil finite difference approach is used to approximate viscous terms.

  16. Global monopoles can change Universe's topology

    Energy Technology Data Exchange (ETDEWEB)

    Marunović, Anja, E-mail: a.marunovic@uu.nl; Prokopec, Tomislav, E-mail: t.prokopec@uu.nl

    2016-05-10

    If the Universe undergoes a phase transition, at which global monopoles are created or destroyed, topology of its spatial sections can change. More specifically, by making use of Myers' theorem, we show that, after a transition in which global monopoles form, spatial sections of a spatially flat, infinite Universe becomes finite and closed. This implies that global monopoles can change the topology of Universe's spatial sections (from infinite and open to finite and closed). Global monopoles cannot alter the topology of the space-time manifold.

  17. Global monopoles can change Universe's topology

    International Nuclear Information System (INIS)

    Marunović, Anja; Prokopec, Tomislav

    2016-01-01

    If the Universe undergoes a phase transition, at which global monopoles are created or destroyed, topology of its spatial sections can change. More specifically, by making use of Myers' theorem, we show that, after a transition in which global monopoles form, spatial sections of a spatially flat, infinite Universe becomes finite and closed. This implies that global monopoles can change the topology of Universe's spatial sections (from infinite and open to finite and closed). Global monopoles cannot alter the topology of the space-time manifold.

  18. Factors that affect the physical science career interest of female students: Testing five common hypotheses

    Science.gov (United States)

    Hazari, Zahra; Potvin, Geoff; Lock, Robynne M.; Lung, Florin; Sonnert, Gerhard; Sadler, Philip M.

    2013-12-01

    There are many hypotheses regarding factors that may encourage female students to pursue careers in the physical sciences. Using multivariate matching methods on national data drawn from the Persistence Research in Science and Engineering (PRiSE) project (n=7505), we test the following five commonly held beliefs regarding what factors might impact females’ physical science career interest: (i) having a single-sex physics class, (ii) having a female physics teacher, (iii) having female scientist guest speakers in physics class, (iv) discussing the work of female scientists in physics class, and (v) discussing the underrepresentation of women in physics class. The effect of these experiences on physical science career interest is compared for female students who are matched on several factors, including prior science interests, prior mathematics interests, grades in science, grades in mathematics, and years of enrollment in high school physics. No significant effects are found for single-sex classes, female teachers, female scientist guest speakers, and discussing the work of female scientists. However, discussions about women’s underrepresentation have a significant positive effect.

  19. Economic stress in childhood and adulthood, and poor psychological health: three life course hypotheses.

    Science.gov (United States)

    Lindström, Martin; Fridh, Maria; Rosvall, Maria

    2014-02-28

    Investigations of mental health in a life course perspective are scarce. The aim is to investigate associations between economic stress in childhood and adulthood, and poor psychological health in adulthood with reference to the accumulation, critical period and social mobility hypotheses in life course epidemiology. The 2008 public health survey in Skåne is a cross-sectional postal questionnaire study. A random sample was invited which yielded 28,198 respondents aged 18-80 (55% participation). Psychological health was assessed with the GHQ12 instrument. Logistic regression models were used to investigate the associations adjusting for age, country of birth, socioeconomic status, emotional support, instrumental support and trust, and stratifying by sex. The accumulation hypothesis was confirmed because combined childhood and adulthood exposures to economic stress were associated with poor psychological health in a graded manner. The social mobility hypothesis was also confirmed. The critical period hypothesis was not confirmed because both childhood and adulthood economic stress remained significantly associated with poor psychological health in adulthood. Economic stress in childhood is associated with mental health in adulthood. © 2013 Published by Elsevier Ireland Ltd.

  20. Testing competing hypotheses for chronology and intensity of lesser scaup molt during winter and spring migration

    Science.gov (United States)

    Anteau, M.J.; Anteau, A.C.E.; Afton, A.D.

    2011-01-01

    We examined chronology and intensity of molt and their relationships to nutrient reserves (lipid and protein) of Lesser Scaup (Aythya affinis) to test predictions of two competing hypotheses. The "staggered cost" hypothesis states that contour-feather molt is nutritionally costly and should not occur during nutritionally costly periods of the annual cycle unless adequate nutrients are available. The "breeding plumage" hypothesis states that prealternate molt must be complete prior to nesting, regardless of nutrient availability. Males and females were completing prebasic molt during winter (Louisiana) and had similar molt intensities. Females underwent prealternate molt during spring migration (Illinois and Minnesota) and prebreeding (Manitoba) periods; 53% and 93% of females were in moderate to heavy molt in Minnesota and Manitoba, respectively, despite experiencing other substantial nutritional costs. Intensity of prealternate molt was not correlated with lipid reserves even though females, on average, were nutritionally stressed. Molt intensity was not negatively correlated with protein reserves at any location. Chronology and intensity of prealternate molt varied little and were not temporally staggered from other nutritionally costly events. Prealternate molt did not influence nutrient reserves, and nutrient reserves likely were not the ultimate factor influencing chronology or intensity of prealternate molt of females. We surmise that nutrients required for prealternate molt come from exogenous sources and that the "staggered cost" hypothesis does not explain chronology of prealternate molt in female Lesser Scaup; rather, it appears that molt must be complete prior to nesting, consistent with the "breeding plumage" hypothesis. ?? The Cooper Ornithological Society 2011.

  1. Use of spatial analysis to test hypotheses on plant recruitment in a hyper-arid ecosystem.

    Directory of Open Access Journals (Sweden)

    Jan J Quets

    Full Text Available Mounds originating from wind-blown sediment accumulation beneath vegetation (nebkhas often indicate land degradation in dry areas. Thus far, most nebkha research has focused on individual plants. Here, we aimed to explore population-scale processes (up to scales of about 100 m that might explain an observed nebkha landscape pattern. We mapped the Rhazya stricta Decne. population in a 3 ha study site in a hyper-arid region of Saudi Arabia. We compared the spatial patterns of five different cohorts (age classes of observed nebkha host plants to those expected under several hypothesized drivers of recruitment and intraspecific interaction. We found that all R. stricta cohorts had a limited fractional vegetation cover and established in large-scale clusters. This clustering weakened with cohort age, possibly indicating merging of neighboring vegetation patches. Different cohort clusters did not spatially overlap in most cases, indicating that recruitment patterns changed position over time. Strong indications were found that the main drivers underlying R. stricta spatial configurations were allogenic (i.e. not driven by vegetation and dynamic. Most likely these drivers were aeolian-driven sand movement or human disturbance which forced offspring recruitment in spatially dynamic clusters. Competition and facilitation were likely active on the field site too, but apparently had a limited effect on the overall landscape structure.

  2. Use of spatial analysis to test hypotheses on plant recruitment in a hyper-arid ecosystem.

    Science.gov (United States)

    Quets, Jan J; Temmerman, Stijn; El-Bana, Magdy I; Al-Rowaily, Saud L; Assaeed, Abdulaziz M; Nijs, Ivan

    2014-01-01

    Mounds originating from wind-blown sediment accumulation beneath vegetation (nebkhas) often indicate land degradation in dry areas. Thus far, most nebkha research has focused on individual plants. Here, we aimed to explore population-scale processes (up to scales of about 100 m) that might explain an observed nebkha landscape pattern. We mapped the Rhazya stricta Decne. population in a 3 ha study site in a hyper-arid region of Saudi Arabia. We compared the spatial patterns of five different cohorts (age classes) of observed nebkha host plants to those expected under several hypothesized drivers of recruitment and intraspecific interaction. We found that all R. stricta cohorts had a limited fractional vegetation cover and established in large-scale clusters. This clustering weakened with cohort age, possibly indicating merging of neighboring vegetation patches. Different cohort clusters did not spatially overlap in most cases, indicating that recruitment patterns changed position over time. Strong indications were found that the main drivers underlying R. stricta spatial configurations were allogenic (i.e. not driven by vegetation) and dynamic. Most likely these drivers were aeolian-driven sand movement or human disturbance which forced offspring recruitment in spatially dynamic clusters. Competition and facilitation were likely active on the field site too, but apparently had a limited effect on the overall landscape structure.

  3. The madness of Dionysus -- six hypotheses on the illness of Nietzsche.

    Science.gov (United States)

    Tényi, Tamás

    2012-01-01

    Friedrich Nietzsche (1844-1900) is considered as one of the most influential modern thinkers of the last two centuries. The great philosopher and poet developed a mental illness at the age of 44 and died at the age of 56. Pathological examination was not undertaken. At that time Nietzsche was diagnosed as having atypical paralysis progressiva, however recently five other probable diagnoses appeared in literature. Literature search in MEDLINE and Web of Science on the illness of Nietzsche. Six hypotheses were identified: 1. Paralysis progressiva (General paralysis of the insane) 2. Bipolar affective disorder followed by vascular dementia 3. Hereditary form of frontotemporal dementia 4. Brain tumor 5. Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) 6. Mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS) syndrome. Developments in neurology and molecular genetics give new perspectives to the secret of Nietzsche's illness and also there is a consensus on the questioning of the original paralysis progressiva concept. As there was no postmortem, the clinical speculations on the medical problems of the great philosopher remain a challenge.

  4. Scientifically based nurture and nature: alternative but non exclusive hypotheses on attention development.

    Science.gov (United States)

    Chiappedi, Matteo; Balottin, Umberto; Baschenis, Ilaria M C; Piazza, Fausta; De Bernardi, Elisabetta; Bejor, Maurizio

    2010-11-01

    Attention is an important neuropsychological function in child development. A lot of literature has been devoted to trying to separate the role of nature (i.e. mainly the genetic basis) from that of nurture (i.e. parenting and life events). The case of preterm born children is an opportunity to try and further study this relationship. We hypothesize that children born preterm might have a reduced attention due to an interaction of factors, to be conceptualized both as nature (mainly the genetic background and the specific consequences of preterm birth and of its complications) and nurture (therapeutic techniques used, alteration in parents-child relationship and so on). The contribution of each of these factors needs to be disembodied from the raw finding of a reduced attention: this is especially important because experience-dependent learning, in which individualized experiences have neural effects, can go on throughout life and this opens interesting rehabilitative possibilities. Different research lines which could be useful to entangle the specific contributions of the above mentioned factors are discussed: the results could in turn inform clinical practice with this highly at risk and increasing in number population, with a view largely corresponding to the one founding the OMS International Classification of Disability, Functioning and Health. Copyright © 2010 Elsevier Ltd. All rights reserved.

  5. Systems analysis of transcriptome data provides new hypotheses about Arabidopsis root response to nitrate treatments

    Directory of Open Access Journals (Sweden)

    Javier eCanales

    2014-02-01

    Full Text Available Nitrogen (N is an essential macronutrient for plant growth and development. Plants adapt to changes in N availability partly by changes in global gene expression. We integrated publicly available root microarray data under contrasting nitrate conditions to identify new genes and functions important for adaptive nitrate responses in Arabidopsis thaliana roots. Overall, more than two thousand genes exhibited changes in expression in response to nitrate treatments in Arabidopsis thaliana root organs. Global regulation of gene expression by nitrate depends largely on the experimental context. However, despite significant differences from experiment to experiment in the identity of regulated genes, there is a robust nitrate response of specific biological functions. Integrative gene network analysis uncovered relationships between nitrate-responsive genes and eleven highly co-expressed gene clusters (modules. Four of these gene network modules have robust nitrate responsive functions such as transport, signaling and metabolism. Network analysis hypothesized G2-like transcription factors are key regulatory factors controlling transport and signaling functions. Our meta-analysis highlights the role of biological processes not studied before in the context of the nitrate response such as root hair development and provides testable hypothesis to advance our understanding of nitrate responses in plants.

  6. Hallucinations and REM sleep behaviour disorder in Parkinson's disease: dream imagery intrusions and other hypotheses.

    Science.gov (United States)

    Manni, Raffaele; Terzaghi, Michele; Ratti, Pietro-Luca; Repetto, Alessandra; Zangaglia, Roberta; Pacchetti, Claudio

    2011-12-01

    REM sleep behaviour disorder (RBD) is a REM sleep-related parasomnia which may be considered a "dissociated state of wakefulness and sleep", given that conflicting elements of REM sleep (dreaming) and of wakefulness (sustained muscle tone and movements) coexist during the episodes, leading to motor and behavioural manifestations reminiscent of an enacted dream. RBD has been reported in association with α-synucleinopathies: around a third of patients with Parkinson's disease (PD) have full-blown RBD. Recent data indicate that PD patients with RBD are more prone to hallucinations than PD patients without this parasomnia. However it is still not clear why RBD in PD is associated with an increased prevalence of VHs. Data exist which suggest that visual hallucinations in PD may be the result of untimely intrusions of REM visual imagery into wakefulness. RBD, which is characterised by a REM sleep dissociation pattern, might be a condition that particularly favours such intrusions. However, other hypotheses may be advanced. In fact, deficits in attentional, executive, visuoperceptual and visuospatial abilities have been documented in RBD and found to occur far more frequently in PD with RBD than in PD without RBD. Neuropsychological deficits involving visual perception and attentional processes are thought to play an important role in the pathophysiology of VHs. On this basis, RBD in PD could be viewed as a contributory risk factor for VHs. Copyright © 2010 Elsevier Inc. All rights reserved.

  7. What drove reversions to quadrupedality in ornithischian dinosaurs? Testing hypotheses using centre of mass modelling.

    Science.gov (United States)

    Maidment, Susannah C R; Henderson, Donald M; Barrett, Paul M

    2014-11-01

    The exceptionally rare transition to quadrupedalism from bipedal ancestors occurred on three independent occasions in ornithischian dinosaurs. The possible driving forces behind these transitions remain elusive, but several hypotheses-including the development of dermal armour and the expansion of head size and cranial ornamentation-have been proposed to account for this major shift in stance. We modelled the position of the centre of mass (CoM) in several exemplar ornithischian taxa and demonstrate that the anterior shifts in CoM position associated with the development of an enlarged skull ornamented with horns and frills for display/defence may have been one of the drivers promoting ceratopsian quadrupedality. A posterior shift in CoM position coincident with the development of extensive dermal armour in thyreophorans demonstrates this cannot have been a primary causative mechanism for quadrupedality in this clade. Quadrupedalism developed in response to different selective pressures in each ornithischian lineage, indicating different evolutionary pathways to convergent quadrupedal morphology.

  8. Rapid Detection Strategies for the Global Threat of Zika Virus: Current State, New Hypotheses and Limitations

    Directory of Open Access Journals (Sweden)

    Shruti Shukla

    2016-10-01

    Full Text Available The current scenario regarding the widespread Zika virus (ZIKV has resulted in numerous diagnostic studies, specifically in South America and in locations where there is frequent entry of travelers returning from ZIKV-affected areas, including pregnant women with or without clinical symptoms of ZIKV infection. The World Health Organization, WHO, announced that millions of cases of ZIKV are likely to occur in the United States of America in the near future. This situation has created an alarming public health emergency of international concern requiring the detection of this life-threatening viral candidate due to increased cases of newborn microcephaly associated with ZIKV infection. Hence, this review reports possible methods and strategies for the fast and reliable detection of ZIKV with particular emphasis on current updates, knowledge and new hypotheses that might be helpful for medical professionals in poor and developing countries that urgently need to address this problem. In particular, we emphasize liposome-based biosensors. Although these biosensors are currently among the less popular tools for human disease detection, they have become useful tools for the screening and detection of pathogenic bacteria, fungi and viruses because of their versatile advantageous features compared to other sensing devices. This review summarizes the currently available methods employed for the rapid detection of ZIKV and suggests an innovative approach involving the application of a liposome-based hypothesis for the development of new strategies for ZIKV detection and their use as effective biomedicinal tools.

  9. Obesity and Cancer: Existing and New Hypotheses for a Causal Connection

    Directory of Open Access Journals (Sweden)

    Trevor W. Stone

    2018-04-01

    Full Text Available Existing explanations of obesity-associated cancer emphasise direct mutagenic effects of dietary components or hormonal imbalance. Some of these hypotheses are reviewed briefly, but recent evidence suggests a major role for chronic inflammation in cancer risk, possibly involving dietary content. These ideas include the inflammation-induced activation of the kynurenine pathway and its role in feeding and metabolism by activation of the aryl hydrocarbon receptor (AHR and by modulating synaptic transmission in the brain. Evidence for a role of the kynurenine pathway in carcinogenesis then provides a potentially major link between obesity and cancer. A second new hypothesis is based on evidence that serine proteases can deplete cells of the tumour suppressors Deleted in Colorectal Cancer (DCC and neogenin. These enzymes include mammalian chymotryptic proteases released by pro-inflammatory neutrophils and macrophages. Blood levels of chymotrypsin itself increase in parallel with food intake. The mechanistically similar bacterial enzyme subtilisin is widespread in the environment, animal probiotics, meat processing and cleaning products. Simple public health schemes in these areas, with selective serine protease inhibitors and AHR antagonists and could prevent a range of intestinal and other cancers. Keywords: Obesity, Serine proteases, Chymotrypsin, Subtilisin, Dependence receptors, DCC, Kynurenine

  10. Testing hypotheses that link wood anatomy to cavitation resistance and hydraulic conductivity in the genus Acer.

    Science.gov (United States)

    Lens, Frederic; Sperry, John S; Christman, Mairgareth A; Choat, Brendan; Rabaey, David; Jansen, Steven

    2011-05-01

    • Vulnerability to cavitation and conductive efficiency depend on xylem anatomy. We tested a large range of structure-function hypotheses, some for the first time, within a single genus to minimize phylogenetic 'noise' and maximize detection of functionally relevant variation. • This integrative study combined in-depth anatomical observations using light, scanning and transmission electron microscopy of seven Acer taxa, and compared these observations with empirical measures of xylem hydraulics. • Our results reveal a 2 MPa range in species' mean cavitation pressure (MCP). MCP was strongly correlated with intervessel pit structure (membrane thickness and porosity, chamber depth), weakly correlated with pit number per vessel, and not related to pit area per vessel. At the tissue level, there was a strong correlation between MCP and mechanical strength parameters, and some of the first evidence is provided for the functional significance of vessel grouping and thickenings on inner vessel walls. In addition, a strong trade-off was observed between xylem-specific conductivity and MCP. Vessel length and intervessel wall characteristics were implicated in this safety-efficiency trade-off. • Cavitation resistance and hydraulic conductivity in Acer appear to be controlled by a very complex interaction between tissue, vessel network and pit characteristics. © 2010 The Authors. New Phytologist © 2010 New Phytologist Trust.

  11. Some hypotheses regarding the mobile telecommunications services marketing and consumers rights from Romania

    Directory of Open Access Journals (Sweden)

    Nicu Marcu

    2013-06-01

    Full Text Available The current research analysis consumers’ rights concerning personal data processing and confidentiality protection within the public communications sector as they are stated in the 2002/58/CE Directive of the European Parliament and Council from 12th of July 2002. The study objectives are: the way that users/ subscribers get informed about their rights in the field of mobile telephony services; the way that mobile telephony services operators inform their users/ subscribers about the subscription included services; the way that mobile telephony services operators inform their uses/ subscribers about the supplementary services that can be demanded; the rights regarding the personal data processing and confidentiality protection that mobile telephony services consumers agree with; the users/ subscribers rights most frequently broken. The marketing research used a questionnaire based survey during January - March 2013 on a sample of 85 users/ subscribers from Romania. It has a preliminary character, shaping a further investigation activity with a higher thematic coverage and a smaller error under the limit of 5%. The data gathering method was a questionnaire based interview. Data were analyzed using the SPSS informatics program, version 16.0 for Windows. The following statistical functions were used for validating/invalidating the hypotheses: descriptive statistics, factor analysis and correlation function.

  12. In search of a deep psychobiology of hypnosis: visionary hypotheses for a new millennium.

    Science.gov (United States)

    Rossi, E L

    2000-01-01

    This search for the deep psychobiological foundations of hypnosis begins with a review of some of the paradoxes of historical hypnosis and the impasse of current theory. It is proposed that further progress requires a deeper investigation of how psychosocial cues can modulate the mechanisms of healing at the CNS, autonomic, neuroendocrine and cellular-genetic levels. The dynamics of hypnotic communication and healing from the cognitive-behavior level to the cellular-genetic are outlined in four stages: (1) Information transduction between the experiences of consciousness and the limbic-hypothalamic-pituitary system; (2) The psychosomatic network of messenger molecules and their receptors; (3) The immediate early gene protein cascade; and (4) State dependent memory, learning and behavior. Neuroscience research is outlined for its contributions to a mathematical model of how a psychobiological approach to the therapeutic applications of hypnosis and the placebo response could facilitate neurogenesis in the human hippocampus and healing at the cellular-genetic-protein level throughout the body. A series of ten hypotheses is proposed as a guide for theory and research in therapeutic hypnosis utilizing DNA chip technology in the new millennium.

  13. Use of Computational Modeling to Evaluate Hypotheses About the Molecular and Cellular Mechanisms of Bystander Effects

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yuchao; Conolly, Rory B; Andersen, Melvin E.

    2006-11-21

    This report describes the development of a computational systems biology approach to evaluate the hypotheses of molecular and cellular mechanisms of adaptive response to low dose ionizing radiation. Our concept is that computational models of signaling pathways can be developed and linked to biologically based dose response models to evaluate the underlying molecular mechanisms which lead to adaptive response. For development of quantitatively accurate, predictive models, it will be necessary to describe tissues consisting of multiple cell types where the different types each contribute in their own way to the overall function of the tissue. Such a model will probably need to incorporate not only cell type-specific data but also spatial information on the architecture of the tissue and on intercellular signaling. The scope of the current model was more limited. Data obtained in a number of different biological systems were synthesized to describe a chimeric, “average” population cell. Biochemical signaling pathways involved in sensing of DNA damage and in the activation of cell cycle checkpoint controls and the apoptotic path were also included. As with any computational modeling effort, it was necessary to develop these simplified initial descriptions (models) that can be iteratively refined. This preliminary model is a starting point which, with time, can evolve to a level of refinement where large amounts of detailed biological information are synthesized and a capability for robust predictions of dose- and time-response behaviors is obtained.

  14. Computer-mediated communication and interpersonal attraction: an experimental test of two explanatory hypotheses.

    Science.gov (United States)

    Antheunis, Marjolijn L; Valkenburg, Patti M; Peter, Jochen

    2007-12-01

    The aims of this study were (a) to investigate the influence of computer-mediated communication (CMC) on interpersonal attraction and (b) to examine two underlying processes in the CMC-interpersonal attraction relationship. We identified two variables that may mediate the influence of CMC on interpersonal attraction: self-disclosure and direct questioning. Focusing on these potential mediating variables, we tested two explanatory hypotheses: the CMC-induced direct questioning hypothesis and the CMC-induced self-disclosure hypothesis. Eighty-one cross-sex dyads were randomly assigned to one of three experimental conditions: text-only CMC, visual CMC, and face-to-face communication. We did not find a direct effect of CMC on interpersonal attraction. However, we did find two positive indirect effects of text-only CMC on interpersonal attraction: text-only CMC stimulated both self-disclosure and direct questioning, both of which in turn enhanced interpersonal attraction. Results are discussed in light of uncertainty reduction theory and CMC theories.

  15. Evaluation of hypotheses for the cause of the 1886 Charleston earthquake

    Energy Technology Data Exchange (ETDEWEB)

    White, R.M.; Long, L.T. (Law Environmental, Inc., Kennesaw, GA (USA); Georgia Inst. of Tech., Atlanta, GA (USA))

    1989-10-01

    This report describes a geophysical/geological investigation of the earth's crust at seismogenic depths in the Charleston, South Carolina area. This investigation was made for the purpose of narrowing the range of theories that have been used to explain the historic 1886 Charleston earthquake. Since a number of these theories are based on only a portion of the available data, we have established a comprehensive data set in order to allow these hypotheses to be subjected to the entire data set. Specifically, we combined existing and new gravity, magnetic and topographic data in grids of 128 km, 256 km and 1028 km on a side centered on Charleston. Seismic, geologic and drilling data were collected and summarized. A magnetotelluric survey consisting of 12 soundings interpreted to depths of over 40 kilometers defined the bottom of the rigid crust with assistance from seismic reflection and other data. A geologic model of the crust in the area of Charleston was constructed and it defined the locations of Triassic/Jurassic basins Paleozoic plutons in greater detail than has previously been achieved. 102 refs., 75 figs.

  16. Evaluation of hypotheses for the cause of the 1886 Charleston earthquake

    International Nuclear Information System (INIS)

    White, R.M.; Long, L.T.

    1989-10-01

    This report describes a geophysical/geological investigation of the earth's crust at seismogenic depths in the Charleston, South Carolina area. This investigation was made for the purpose of narrowing the range of theories that have been used to explain the historic 1886 Charleston earthquake. Since a number of these theories are based on only a portion of the available data, we have established a comprehensive data set in order to allow these hypotheses to be subjected to the entire data set. Specifically, we combined existing and new gravity, magnetic and topographic data in grids of 128 km, 256 km and 1028 km on a side centered on Charleston. Seismic, geologic and drilling data were collected and summarized. A magnetotelluric survey consisting of 12 soundings interpreted to depths of over 40 kilometers defined the bottom of the rigid crust with assistance from seismic reflection and other data. A geologic model of the crust in the area of Charleston was constructed and it defined the locations of Triassic/Jurassic basins Paleozoic plutons in greater detail than has previously been achieved. 102 refs., 75 figs

  17. Analysis of Lithospheric Stresses Using Satellite Gravimetry: Hypotheses and Applications to North Atlantic

    Science.gov (United States)

    Minakov, A.; Medvedev, S.

    2017-12-01

    Analysis of lithospheric stresses is necessary to gain understanding of the forces that drive plate tectonics and intraplate deformations and the structure and strength of the lithosphere. A major source of lithospheric stresses is believed to be in variations of surface topography and lithospheric density. The traditional approach to stress estimation is based on direct calculations of the Gravitational Potential Energy (GPE), the depth integrated density moment of the lithosphere column. GPE is highly sensitive to density structure which, however, is often poorly constrained. Density structure of the lithosphere may be refined using methods of gravity modeling. However, the resulted density models suffer from non-uniqueness of the inverse problem. An alternative approach is to directly estimate lithospheric stresses (depth integrated) from satellite gravimetry data. Satellite gravity gradient measurements by the ESA GOCE mission ensures a wealth of data for mapping lithospheric stresses if a link between data and stresses or GPE can be established theoretically. The non-uniqueness of interpretation of sources of the gravity signal holds in this case as well. Therefore, the data analysis was tested for the North Atlantic region where reliable additional constraints are supplied by both controlled-source and earthquake seismology. The study involves comparison of three methods of stress modeling: (1) the traditional modeling approach using a thin sheet approximation; (2) the filtered geoid approach; and (3) the direct utilization of the gravity gradient tensor. Whereas the first two approaches (1)-(2) calculate GPE and utilize a computationally expensive finite element mechanical modeling to calculate stresses, the approach (3) uses a much simpler numerical treatment but requires simplifying assumptions that yet to be tested. The modeled orientation of principal stresses and stress magnitudes by each of the three methods are compared with the World Stress Map.

  18. Universal moduli spaces of Riemann surfaces

    Science.gov (United States)

    Ji, Lizhen; Jost, Jürgen

    2017-04-01

    We construct a moduli space for Riemann surfaces that is universal in the sense that it represents compact Riemann surfaces of any finite genus. This moduli space is a connected complex subspace of an infinite dimensional complex space, and is stratified according to genus such that each stratum has a compact closure, and it carries a metric and a measure that induce a Riemannian metric and a finite volume measure on each stratum. Applications to the Plateau-Douglas problem for minimal surfaces of varying genus and to the partition function of Bosonic string theory are outlined. The construction starts with a universal moduli space of Abelian varieties. This space carries a structure of an infinite dimensional locally symmetric space which is of interest in its own right. The key to our construction of the universal moduli space then is the Torelli map that assigns to every Riemann surface its Jacobian and its extension to the Satake-Baily-Borel compactifications.

  19. Homotopies and the Universal Fixed Point Property

    DEFF Research Database (Denmark)

    Szymik, Markus

    2015-01-01

    . To even specify the problem, we introduce the universal fixed point property. Our results apply in particular to the analysis of convex subspaces of Banach spaces, to the topology of finite-dimensional manifolds and CW complexes, and to the combinatorics of Kolmogorov spaces associated with finite posets.......A topological space has the fixed point property if every continuous self-map of that space has at least one fixed point. We demonstrate that there are serious restraints imposed by the requirement that there be a choice of fixed points that is continuous whenever the self-map varies continuously...

  20. Sustainable Universities

    DEFF Research Database (Denmark)

    Grindsted, Thomas Skou

    2011-01-01

    , has put a counter pressure on the university, forcing it to review its role as a driver for sustainable development. Today, universities and intergovernmental institutions have developed more than 31 SHE declarations, and more than 1400 universities have signed a SHE declaration globally. However....... Declarations tend to have impact on three trends. Firstly, there is emerging international consensus on the university’s role and function in relation to sustainable development; secondly, the emergence of national legislation, and thirdly, an emerging international competition to be leader in sustainable......Declarations on Sustainability in Higher Education (SHE) can be viewed as a piece of international regulation. Over the past 30 years research at universities has produced convincing data to warn about deterioration of the environment, resource scarcity and the need for sustainability. This in turn...

  1. USAID University

    Data.gov (United States)

    US Agency for International Development — USAID University is USAID's learning management system. Features include 1) Access online courses 2) Register for instructor-led courses 3)Access your student...

  2. Einstein's Universe.

    Science.gov (United States)

    Carlson, Eric; Wald, Robert

    1979-01-01

    Presents a guide to be used by students and teachers in conjunction with a television program about Einstein. Provides general information about special and general relativity, and the universe. Includes questions for discussion after each section and a bibliography. (MA)

  3. Undulant Universe

    Energy Technology Data Exchange (ETDEWEB)

    Barenboim, Gabriela; /Valencia U.; Mena, Olga; Quigg, Chris; /Fermilab

    2004-12-01

    If the equation of state for ''dark energy'' varies periodically, the expansion of the Universe may have undergone alternating eras of acceleration and deceleration. We examine a specific form that survives existing observational tests, does not single out the present state of the Universe as exceptional, and suggests a future much like the matter-dominated past: a smooth expansion without a final inflationary epoch.

  4. DNA computing based on splicing: universality results.

    Science.gov (United States)

    Csuhaj-Varjú, E; Freund, R; Kari, L; Păun, G

    1996-01-01

    The paper extends some of the most recently obtained results on the computational universality of specific variants of H systems (e.g. with regular sets of rules) and proves that we can construct universal computers based on various types of H systems with a finite set of splicing rules as well as a finite set of axioms, i.e. we show the theoretical possibility to design programmable universal DNA computers based on the splicing operation. For H systems working in the multiset style (where the numbers of copies of all available strings are counted) we elaborate how a Turing machine computing a partial recursive function can be simulated by an equivalent H system computing the same function; in that way, from a universal Turning machine we obtain a universal H system. Considering H systems as language generating devices we have to add various simple control mechanisms (checking the presence/absence of certain symbols in the spliced strings) to systems with a finite set of splicing rules as well as with a finite set of axioms in order to obtain the full computational power, i.e. to get a characterization of the family of recursively enumerable languages. We also introduce test tube systems, where several H systems work in parallel in their tubes and from time to time the contents of each tube are redistributed to all tubes according to certain separation conditions. By the construction of universal test tube systems we show that also such systems could serve as the theoretical basis for the development of biological (DNA) computers.

  5. Finite element simulation of cracks formation in parabolic flume above fixed service live

    Science.gov (United States)

    Bandurin, M. A.; Volosukhin, V. A.; Mikheev, A. V.; Volosukhin, Y. V.; Bandurina, I. P.

    2018-03-01

    In the article, digital simulation data on influence of defect different characteristics on cracks formation in a parabolic flume are presented. The finite element method is based on general hypotheses of the theory of elasticity. The studies showed that the values of absolute movements satisfy the standards of design. The results of the digital simulation of stresses and strains for cracks formation in concrete parabolic flumes after long-term service above the fixed service life are described. Stressed and strained state of reinforced concrete bearing elements under different load combinations is considered. Intensive threshold of danger to form longitudinal cracks in reinforced concrete elements is determined.

  6. Finite-correlation-time effects in the kinematic dynamo problem

    International Nuclear Information System (INIS)

    Schekochihin, Alexander A.; Kulsrud, Russell M.

    2001-01-01

    Most of the theoretical results on the kinematic amplification of small-scale magnetic fluctuations by turbulence have been confined to the model of white-noise-like (δ-correlated in time) advecting turbulent velocity field. In this work, the statistics of the passive magnetic field in the diffusion-free regime are considered for the case when the advecting flow is finite-time correlated. A new method is developed that allows one to systematically construct the correlation-time expansion for statistical characteristics of the field such as its probability density function or the complete set of its moments. The expansion is valid provided the velocity correlation time is smaller than the characteristic growth time of the magnetic fluctuations. This expansion is carried out up to first order in the general case of a d-dimensional arbitrarily compressible advecting flow. The growth rates for all moments of the magnetic-field strength are derived. The effect of the first-order corrections due to the finite correlation time is to reduce these growth rates. It is shown that introducing a finite correlation time leads to the loss of the small-scale statistical universality, which was present in the limit of the δ-correlated velocity field. Namely, the shape of the velocity time-correlation profile and the large-scale spatial structure of the flow become important. The latter is a new effect, that implies, in particular, that the approximation of a locally-linear shear flow does not fully capture the effect of nonvanishing correlation time. Physical applications of this theory include the small-scale kinematic dynamo in the interstellar medium and protogalactic plasmas

  7. Bisphosphonate-induced osteonecrosis of the jaws, bone markers, and a hypothesized candidate gene.

    Science.gov (United States)

    Lehrer, Steven; Montazem, André; Ramanathan, Lakshmi; Pessin-Minsley, Melissa; Pfail, John; Stock, Richard G; Kogan, Rita

    2009-01-01

    To determine whether any abnormality in serum bone markers is related to bisphosphonate-induced osteonecrosis of the jaw. We obtained serum bone markers and other relevant endocrine assays on 7 patients with osteonecrosis of the jaws (ONJ). The assays were C-telopeptide, N-telopeptide, bone specific alkaline phosphatase, osteocalcin, intact parathyroid hormone, T3, T4, TSH, and vitamin D 25 hydroxy. Diagnostic criteria for ONJ were those formulated by the American Association of Oral and Maxillofacial Surgeons. Five of our patients were women. Two had metastatic breast cancer and had been treated with zoledronic acid; 1 had also received pamidronate. Three others had osteoporosis and had been treated with daily alendronate. One man had metastatic prostate cancer treated with zoledronic acid. Another man had Gaucher's disease treated with zoledronic acid. All patients had been withdrawn from bisphosphonate for at least 6 months. None was taking or had taken corticosteroids. None of the lesions had shown any significant healing and all were still causing the patients considerable distress, yet the bone markers were within the normal range as measured in our laboratory, except for intact parathyroid hormone, which was slightly elevated in 1 case of metastatic breast cancer (177 pg/mL). We hypothesize that matrix metalloproteinase 2 (MMP2) is a candidate gene for bisphosphonate-induced ONJ for 3 reasons: 1) MMP2 is associated with bone abnormalities which could be related to ONJ. 2) Bisphosphonates are associated with atrial fibrillation, and MMP2 is the only gene known to be associated with both bone abnormalities and atrial fibrillation. 3) A network of disorders and disease genes linked by known disorder-gene associations indicates that cardiovascular disease and bone disease are closely related, suggesting that a single drug such as bisphosphonate, acting on a single gene, MMP2, could have both bone and cardiovascular side effects different from the osteoclast

  8. EXAMINING HYPOTHESES GENERATED BY FIELD MEASURES OF SEXUAL SELECTION ON MALE LIZARDS, UTA PALMERI.

    Science.gov (United States)

    Hews, Diana K

    1990-12-01

    I examined sexual selection in the iguanid lizard Uta palmeri by measuring phenotypic selection in a cohort of males. Relative fitness was estimated by copulation rate from one breeding season, and I analyzed selection on five morphological traits (snout-vent length, mass, jaw length, head width, and head depth) and on male territory quality. Only territory quality and head depth were identified as direct targets of selection in a linear selection gradient analysis. Head depth was suggested to also be subject to quadratic selection. All traits exhibited significant directional selection differentials, suggesting indirect selection also was present because of the correlation of these traits with direct targets of selection. I used these results to generate hypotheses about the mechanisms of selection. For traits not identified as direct targets of selection (snout-vent length, mass, head width, jaw length), I could accept the null hypothesis of no female preference for the analyzed male traits; if these morphological traits were preferred by females in mate choice, they would have been identified as direct targets of selection. Exploring possible functional relationships within the cohort, I found that all five morphological traits contributed to explaining variation in territorial status. And in staged aggressive interactions between males that were similar in snout-vent length and mass, winning was associated only with greater head depth and not with head width or jaw length. Several possible interpretations of these results are presented. This study suggests that differential mating success arising from variation in territory quality gives rise to indirect selection on morphology. The possible mechanisms giving rise to the proposed direct selection on head depth require further study. © 1990 The Society for the Study of Evolution.

  9. Examining competing hypotheses for the effects of diagrams on recall for text.

    Science.gov (United States)

    Ortegren, Francesca R; Serra, Michael J; England, Benjamin D

    2015-01-01

    Supplementing text-based learning materials with diagrams typically increases students' free recall and cued recall of the presented information. In the present experiments, we examined competing hypotheses for why this occurs. More specifically, although diagrams are visual, they also serve to repeat information from the text they accompany. Both visual presentation and repetition are known to aid students' recall of information. To examine to what extent diagrams aid recall because they are visual or repetitive (or both), we had college students in two experiments (n = 320) read a science text about how lightning storms develop before completing free-recall and cued-recall tests over the presented information. Between groups, we manipulated the format and repetition of target pieces of information in the study materials using a 2 (visual presentation of target information: diagrams present vs. diagrams absent) × 2 (repetition of target information: present vs. absent) between-participants factorial design. Repetition increased both the free recall and cued recall of target information, and this occurred regardless of whether that repetition was in the form of text or a diagram. In contrast, the visual presentation of information never aided free recall. Furthermore, visual presentation alone did not significantly aid cued recall when participants studied the materials once before the test (Experiment 1) but did when they studied the materials twice (Experiment 2). Taken together, the results of the present experiments demonstrate the important role of repetition (i.e., that diagrams repeat information from the text) over the visual nature of diagrams in producing the benefits of diagrams for recall.

  10. Kinetics of cancer: a method to test hypotheses of genetic causation

    Directory of Open Access Journals (Sweden)

    Lipkin Steven M

    2005-12-01

    Full Text Available Abstract Background Mouse studies have recently compared the age-onset patterns of cancer between different genotypes. Genes associated with earlier onset are tentatively assigned a causal role in carcinogenesis. These standard analyses ignore the great amount of information about kinetics contained in age-onset curves. We present a method for analyzing kinetics that measures quantitatively the causal role of candidate genes in cancer progression. We use our method to demonstrate a clear association between somatic mutation rates of different DNA mismatch repair (MMR genotypes and the kinetics of cancer progression. Methods Most experimental studies report age-onset curves as the fraction diagnosed with tumors at each age for each group. We use such data to estimate smoothed survival curves, then measure incidence rates at each age by the slope of the fitted curve divided by the fraction of mice that remain undiagnosed for tumors at that age. With the estimated incidence curves, we compare between different genotypes the median age of cancer onset and the acceleration of cancer, which is the rate of increase in incidence with age. Results The direction of change in somatic mutation rate between MMR genotypes predicts the direction of change in the acceleration of cancer onset in all 7 cases (p ˜ 0.008, with the same result for the association between mutation rate and the median age of onset. Conclusion Many animal experiments compare qualitatively the onset curves for different genotypes. If such experiments were designed to analyze kinetics, the research could move to the next stage in which the mechanistic consequences of particular genetic pathways are related to the dynamics of carcinogenesis. The data we analyzed here were not collected to test mechanistic and quantitative hypotheses about kinetics. Even so, a simple reanalysis revealed significant insights about how DNA repair genotypes affect separately the age of onset and the

  11. Functional relations between locomotor performance traits in spiders and implications for evolutionary hypotheses

    Directory of Open Access Journals (Sweden)

    Taylor Phillip W

    2010-11-01

    Full Text Available Abstract Background Locomotor performance in ecologically relevant activities is often linked to individual fitness. Recent controversy over evolution of extreme sexual size dimorphism (SSD in spiders centres on the relationship between size and locomotor capacity in males. Advantages for large males running over horizontal surfaces and small males climbing vertically have been proposed. Models have implicitly treated running and climbing as functionally distinct activities and failed to consider the possibility that they reflect common underlying capacities. Findings We examine the relationship between maximum climbing and running performance in males of three spider species. Maximum running and climbing speeds were positively related in two orb-web spiders with high SSD (Argiope keyserlingi and Nephila plumipes, indicating that for these species assays of running and climbing largely reveal the same underlying capacities. Running and climbing speeds were not related in a jumping spider with low SSD (Jacksonoides queenslandica. We found no evidence of a performance trade-off between these activities. Conclusions In the web-spiders A. keyserlingi and N. plumipes good runners were also good climbers. This indicates that climbing and running largely represent a single locomotor performance characteristic in these spiders, but this was not the case for the jumping spider J. queenslandica. There was no evidence of a trade-off between maximum running and climbing speeds in these spiders. We highlight the need to establish the relationship between apparently disparate locomotor activities when testing alternative hypotheses that yield predictions about different locomotor activities. Analysis of slopes suggests greater potential for an evolutionary response on performance in the horizontal compared to vertical context in these spiders.

  12. The impacts of comparative anatomy of electric rays (Batoidea: Torpediniformes) on their systematic hypotheses.

    Science.gov (United States)

    Claeson, Kerin M

    2014-06-01

    The Comparative anatomy of the 11 recognized genera within Torpediniformes is described, systematically categorized, and illustrated in a comprehensive photo-atlas. Data are compiled into a character matrix and cladistically analyzed using parsimony to test hypotheses about the previously recognized subfamilies, while reconstructing the possible evolutionary history of Torpediniformes. Results are consistent with the previous rank-based classifications, regardless of the parsimony criteria used to generate the phylogenetic hypothesis, with one notable exception: a monophyletic Narcininae was never recovered. Torpedinoidea (=Hypnos + Torpedo) is supported by the presence of long, slender, flexible jaw cartilages, absence of a large rostral fontanelle, presence of suprascapular antimeres that are each shorter than the scapular process of the scapulocoracoid, antorbital cartilages that articulate on the anterior aspect of the nasal capsules and absence of a frontoparietal fontanelle. Subfamilial names Hypninae and Torpedininae are redundant with the genus names Hypnos and Torpedo and are not adopted here. Narcinoidea (=nontorpedinoid torpediniforms) is supported by unambiguous character transformations to the presence of a divided lower lip, labial cartilages, laterolingually compressed palatoquadrates, bifurcated antorbital cartilages, a rostral fontanelle, ventrally projecting nasal capsules, a dorsal rim of the synarcual mouth posterior to occipital condyle, posteriorly positioned lateral stays, and obtuse anterior margins of lateral stays. Narkidae is supported by unambiguous character transformations to the presence of an uncovered eye that protrudes above dorsal surface, a shared rim between the spiracle and the eye, an anterior nasal turret that projects ventrally, a nasal curtain that covers the upper lip and dentition when the mouth is closed, tab-like prepelvic processes, a mesopterygium that is shorter than propterygium but longer than metapterygium, a

  13. Cholinergic Hypofunction in Presbycusis-Related Tinnitus With Cognitive Function Impairment: Emerging Hypotheses

    Directory of Open Access Journals (Sweden)

    Qingwei Ruan

    2018-04-01

    Full Text Available Presbycusis (age-related hearing loss is a potential risk factor for tinnitus and cognitive deterioration, which result in poor life quality. Presbycusis-related tinnitus with cognitive impairment is a common phenotype in the elderly population. In these individuals, the central auditory system shows similar pathophysiological alterations as those observed in Alzheimer’s disease (AD, including cholinergic hypofunction, epileptiform-like network synchronization, chronic inflammation, and reduced GABAergic inhibition and neural plasticity. Observations from experimental rodent models indicate that recovery of cholinergic function can improve memory and other cognitive functions via acetylcholine-mediated GABAergic inhibition enhancement, nicotinic acetylcholine receptor (nAChR-mediated anti-inflammation, glial activation inhibition and neurovascular protection. The loss of cholinergic innervation of various brain structures may provide a common link between tinnitus seen in presbycusis-related tinnitus and age-related cognitive impairment. We hypothesize a key component of the condition is the withdrawal of cholinergic input to a subtype of GABAergic inhibitory interneuron, neuropeptide Y (NPY neurogliaform cells. Cholinergic denervation might not only cause the degeneration of NPY neurogliaform cells, but may also result in decreased AChR activation in GABAergic inhibitory interneurons. This, in turn, would lead to reduced GABA release and inhibitory regulation of neural networks. Reduced nAChR-mediated anti-inflammation due to the loss of nicotinic innervation might lead to the transformation of glial cells and release of inflammatory mediators, lowering the buffering of extracellular potassium and glutamate metabolism. Further research will provide evidence for the recovery of cholinergic function with the use of cholinergic input enhancement alone or in combination with other rehabilitative interventions to reestablish inhibitory regulation

  14. Cholinergic Hypofunction in Presbycusis-Related Tinnitus With Cognitive Function Impairment: Emerging Hypotheses.

    Science.gov (United States)

    Ruan, Qingwei; Yu, Zhuowei; Zhang, Weibin; Ruan, Jian; Liu, Chunhui; Zhang, Ruxin

    2018-01-01

    Presbycusis (age-related hearing loss) is a potential risk factor for tinnitus and cognitive deterioration, which result in poor life quality. Presbycusis-related tinnitus with cognitive impairment is a common phenotype in the elderly population. In these individuals, the central auditory system shows similar pathophysiological alterations as those observed in Alzheimer's disease (AD), including cholinergic hypofunction, epileptiform-like network synchronization, chronic inflammation, and reduced GABAergic inhibition and neural plasticity. Observations from experimental rodent models indicate that recovery of cholinergic function can improve memory and other cognitive functions via acetylcholine-mediated GABAergic inhibition enhancement, nicotinic acetylcholine receptor (nAChR)-mediated anti-inflammation, glial activation inhibition and neurovascular protection. The loss of cholinergic innervation of various brain structures may provide a common link between tinnitus seen in presbycusis-related tinnitus and age-related cognitive impairment. We hypothesize a key component of the condition is the withdrawal of cholinergic input to a subtype of GABAergic inhibitory interneuron, neuropeptide Y (NPY) neurogliaform cells. Cholinergic denervation might not only cause the degeneration of NPY neurogliaform cells, but may also result in decreased AChR activation in GABAergic inhibitory interneurons. This, in turn, would lead to reduced GABA release and inhibitory regulation of neural networks. Reduced nAChR-mediated anti-inflammation due to the loss of nicotinic innervation might lead to the transformation of glial cells and release of inflammatory mediators, lowering the buffering of extracellular potassium and glutamate metabolism. Further research will provide evidence for the recovery of cholinergic function with the use of cholinergic input enhancement alone or in combination with other rehabilitative interventions to reestablish inhibitory regulation mechanisms of

  15. Confidence judgment in depression and dysphoria: the depressive realism vs. negativity hypotheses.

    Science.gov (United States)

    Szu-Ting Fu, Tiffany; Koutstaal, Wilma; Poon, Lucia; Cleare, Anthony J

    2012-06-01

    According to the negativity hypothesis, depressed individuals are over-pessimistic due to negative self-concepts. In contrast, depressive realism suggests that depressed persons are realistic compared to their nondepressed controls. However, evidence supporting depressive realism predominantly comes from judgment comparisons between controls and nonclinical dysphoric samples when the controls showed overconfident bias. This study aimed to test the validity of the two accounts in clinical depression and dysphoria. Sixty-eight participants, including healthy controls (n = 32), patients with DSM-IV major depression (n = 20), and dysphoric participants with CDC-defined chronic fatigue syndrome (n = 16) performed an adjective recognition task and reported their item-by-item confidence judgments and post-test performance estimate (PTPE). Compared to realistic PTPE made by the controls, patients with major depression showed significant underconfidence. The PTPE of the dysphoric participants was relatively accurate. Both the depressed and dysphoric participants displayed less item-by-item overconfidence as opposed to significant item-by-item overconfidence shown by the controls. The judgment-accuracy patterns of the three groups need to be replicated with larger samples using non-memory task domains. The present study confirms depressive realism in dysphoric individuals. However, toward a more severe depressive emotional state, the findings did not support depressive realism but are in line with the prediction of the negativity hypothesis. It is not possible to determine the validity of the two hypotheses when the controls are overconfident. Dissociation between item-by-item and retrospective confidence judgments is discussed. Copyright © 2011 Elsevier Ltd. All rights reserved.

  16. Retraining the addicted brain: a review of hypothesized neurobiological mechanisms of mindfulness-based relapse prevention.

    Science.gov (United States)

    Witkiewitz, Katie; Lustyk, M Kathleen B; Bowen, Sarah

    2013-06-01

    Addiction has generally been characterized as a chronic relapsing condition (Leshner, 1999). Several laboratory, preclinical, and clinical studies have provided evidence that craving and negative affect are strong predictors of the relapse process. These states, as well as the desire to avoid them, have been described as primary motives for substance use. A recently developed behavioral treatment, mindfulness-based relapse prevention (MBRP), was designed to target experiences of craving and negative affect and their roles in the relapse process. MBRP offers skills in cognitive-behavioral relapse prevention integrated with mindfulness meditation. The mindfulness practices in MBRP are intended to increase discriminative awareness, with a specific focus on acceptance of uncomfortable states or challenging situations without reacting "automatically." A recent efficacy trial found that those randomized to MBRP, as compared with those in a control group, demonstrated significantly lower rates of substance use and greater decreases in craving following treatment. Furthermore, individuals in MBRP did not report increased craving or substance use in response to negative affect. It is important to note, areas of the brain that have been associated with craving, negative affect, and relapse have also been shown to be affected by mindfulness training. Drawing from the neuroimaging literature, we review several plausible mechanisms by which MBRP might be changing neural responses to the experiences of craving and negative affect, which subsequently may reduce risk for relapse. We hypothesize that MBRP may affect numerous brain systems and may reverse, repair, or compensate for the neuroadaptive changes associated with addiction and addictive-behavior relapse. 2013 APA, all rights reserved

  17. The missing link of Jewish European ancestry: contrasting the Rhineland and the Khazarian hypotheses.

    Science.gov (United States)

    Elhaik, Eran

    2013-01-01

    The question of Jewish ancestry has been the subject of controversy for over two centuries and has yet to be resolved. The "Rhineland hypothesis" depicts Eastern European Jews as a "population isolate" that emerged from a small group of German Jews who migrated eastward and expanded rapidly. Alternatively, the "Khazarian hypothesis" suggests that Eastern European Jews descended from the Khazars, an amalgam of Turkic clans that settled the Caucasus in the early centuries CE and converted to Judaism in the 8th century. Mesopotamian and Greco-Roman Jews continuously reinforced the Judaized empire until the 13th century. Following the collapse of their empire, the Judeo-Khazars fled to Eastern Europe. The rise of European Jewry is therefore explained by the contribution of the Judeo-Khazars. Thus far, however, the Khazars' contribution has been estimated only empirically, as the absence of genome-wide data from Caucasus populations precluded testing the Khazarian hypothesis. Recent sequencing of modern Caucasus populations prompted us to revisit the Khazarian hypothesis and compare it with the Rhineland hypothesis. We applied a wide range of population genetic analyses to compare these two hypotheses. Our findings support the Khazarian hypothesis and portray the European Jewish genome as a mosaic of Near Eastern-Caucasus, European, and Semitic ancestries, thereby consolidating previous contradictory reports of Jewish ancestry. We further describe a major difference among Caucasus populations explained by the early presence of Judeans in the Southern and Central Caucasus. Our results have important implications for the demographic forces that shaped the genetic diversity in the Caucasus and for medical studies.

  18. Linking Network Activity to Synaptic Plasticity during Sleep: Hypotheses and Recent Data.

    Science.gov (United States)

    Puentes-Mestril, Carlos; Aton, Sara J

    2017-01-01

    Research findings over the past two decades have supported a link between sleep states and synaptic plasticity. Numerous mechanistic hypotheses have been put forth to explain this relationship. For example, multiple studies have shown structural alterations to synapses (including changes in synaptic volume, spine density, and receptor composition) indicative of synaptic weakening after a period of sleep. Direct measures of neuronal activity and synaptic strength support the idea that a period of sleep can reduce synaptic strength. This has led to the synaptic homeostasis hypothesis (SHY), which asserts that during slow wave sleep, synapses are downscaled throughout the brain to counteract net strengthening of network synapses during waking experience (e.g., during learning). However, neither the cellular mechanisms mediating these synaptic changes, nor the sleep-dependent activity changes driving those cellular events are well-defined. Here we discuss potential cellular and network dynamic mechanisms which could underlie reductions in synaptic strength during sleep. We also discuss recent findings demonstrating circuit-specific synaptic strengthening (rather than weakening) during sleep. Based on these data, we explore the hypothetical role of sleep-associated network activity patterns in driving synaptic strengthening. We propose an alternative to SHY-namely that depending on experience during prior wake, a variety of plasticity mechanisms may operate in the brain during sleep. We conclude that either synaptic strengthening or synaptic weakening can occur across sleep, depending on changes to specific neural circuits (such as gene expression and protein translation) induced by experiences in wake. Clarifying the mechanisms underlying these different forms of sleep-dependent plasticity will significantly advance our understanding of how sleep benefits various cognitive functions.

  19. Finite element model updating of the UCF grid benchmark using measured frequency response functions

    Science.gov (United States)

    Sipple, Jesse D.; Sanayei, Masoud

    2014-05-01

    A frequency response function based finite element model updating method is presented and used to perform parameter estimation of the University of Central Florida Grid Benchmark Structure. The proposed method is used to calibrate the initial finite element model using measured frequency response functions from the undamaged, intact structure. Stiffness properties, mass properties, and boundary conditions of the initial model were estimated and updated. Model updating was then performed using measured frequency response functions from the damaged structure to detect physical structural change. Grouping and ungrouping were utilized to determine the exact location and magnitude of the damage. The fixity in rotation of two boundary condition nodes was accurately and successfully estimated. The usefulness of the proposed method for finite element model updating is shown by being able to detect, locate, and quantify change in structural properties.

  20. A Comparison of Continuous Mass-lumped Finite Elements and Finite Differences for 3D

    NARCIS (Netherlands)

    Zhebel, E.; Minisini, S.; Kononov, A.; Mulder, W.A.

    2012-01-01

    The finite-difference method is widely used for time-domain modelling of the wave equation because of its ease of implementation of high-order spatial discretization schemes, parallelization and computational efficiency. However, finite elements on tetrahedral meshes are more accurate in complex

  1. Environmental isotopes to test hypotheses for fluid mud (mud bank) generation mechanisms along the southwest coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Jacob, N.; Ansari, M.A.; Revichandran, C.

    Occurrence of fluid mud (mud banks) in the southwest coast of India is an enigma for the scientific community. Over the years, several multi-disciplinary studies were conducted and various hypotheses were postulated on the occurrence and sustenance...

  2. Finite density aspects of leptogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Hohenegger, Andreas

    2010-02-08

    Leptogenesis is a model for the dynamical generation of the matter-antimatter asymmetry. This process takes place in the early universe at very high temperatures and a deviation from equilibrium is a fundamental requirement for the formation of the asymmetry. The equations used for its description originate from classical Boltzmann equations (BEs), which were refined using thermal propagators. In view of the basic restrictions of BEs, it is desirable to develop a systematic approach which uses non-equilibrium QFT as starting point. In this thesis modified BEs are used which are derived from first principles in the Kadanoff-Baym formalism. This is done for a simple toy model which is sufficiently intricate to study popular scenarios such as thermal leptogenesis in analogy to the phenomenological theory. This approach uncovers the structure of the corrected BEs and leads to a new result for the form of the thermal contributions to the CP-violating parameter, so that the established one must be reconsidered. It turns out that the different approaches can be reconciled. The new form predicts an enhancement of the asymmetry. The quantitative implications of the medium corrections within the toy model are studied numerically in terms of the full BEs. (orig.)

  3. Finite density aspects of leptogenesis

    International Nuclear Information System (INIS)

    Hohenegger, Andreas

    2010-01-01

    Leptogenesis is a model for the dynamical generation of the matter-antimatter asymmetry. This process takes place in the early universe at very high temperatures and a deviation from equilibrium is a fundamental requirement for the formation of the asymmetry. The equations used for its description originate from classical Boltzmann equations (BEs), which were refined using thermal propagators. In view of the basic restrictions of BEs, it is desirable to develop a systematic approach which uses non-equilibrium QFT as starting point. In this thesis modified BEs are used which are derived from first principles in the Kadanoff-Baym formalism. This is done for a simple toy model which is sufficiently intricate to study popular scenarios such as thermal leptogenesis in analogy to the phenomenological theory. This approach uncovers the structure of the corrected BEs and leads to a new result for the form of the thermal contributions to the CP-violating parameter, so that the established one must be reconsidered. It turns out that the different approaches can be reconciled. The new form predicts an enhancement of the asymmetry. The quantitative implications of the medium corrections within the toy model are studied numerically in terms of the full BEs. (orig.)

  4. Universality of TMD correlators

    Directory of Open Access Journals (Sweden)

    Buffing M.G.A.

    2015-01-01

    Full Text Available In a high-energy scattering process with hadrons in the initial state, color is involved. Transverse momentum dependent distribution functions (TMDs describe the quark and gluon distributions in these hadrons in momentum space with the inclusion of transverse directions. Apart from the (anti-quarks and gluons that are involved in the hard scattering process, additional gluon emissions by the hadrons have to be taken into account as well, giving rise to Wilson lines or gauge links. The TMDs involved are sensitive to the process under consideration and hence potentially nonuniversal due to these Wilson line interactions with the hard process; different hard processes give rise to different Wilson line structures. We will show that in practice only a finite number of universal TMDs have to be considered, which come in different linear combinations depending on the hard process under consideration, ensuring a generalized universality. For quarks this gives rise to three Pretzelocity functions, whereas for gluons a richer structure of functions arises.

  5. A matrix free, partitioned solution of fluid-structure interaction problems using finite volume and finite element methods

    CSIR Research Space (South Africa)

    Suliman, Ridhwaan

    2015-01-01

    Full Text Available A fully-coupled partitioned finite volume–finite volume and hybrid finite volume–finite element fluid-structure interaction scheme is presented. The fluid domain is modelled as a viscous incompressible isothermal region governed by the Navier...

  6. Fringe—A Java-based finite fringe analysis package

    Science.gov (United States)

    McIntyre, Timothy J.; Bishop, Alexis I.

    2012-09-01

    A package for analysing two-dimensional finite fringe interferograms is described. Through a combination of automatic and interactive routines, an interferogram can be processed to extract the phase shift imparted on the recording light by a transparent object. The package consists of routines to condition and pad the original image for Fourier transform analysis, to filter the image and obtain the phase, to unwrap the phase, and to remove the background phase ramp. A sample image recorded using holographic interferometry is successfully analysed. Program summary Program title: FRINGE Catalogue identifier: AEMM_v1_0 Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AEMM_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 134006 No. of bytes in distributed program, including test data, etc.: 4029801 Distribution format: tar.gz Programming language: Java. Computer: Personal Computers. Operating system: Mac OS X, Windows XP, Linux and any other system that can run Java Jar files. RAM: 1GB recommended Classification: 18. Nature of problem: A standalone multi-platform program to perform analysis of finite fringe interferograms. Solution method: Fourier filtering approach with phase unwrapping and background subtraction. Restrictions: Designed to analyse square images. Running time: Interactive processing takes several minutes. Minimal cpu time.

  7. Density functional theory study of finite carbon chains.

    Science.gov (United States)

    Fan, XiaoFeng; Liu, Lei; Lin, JianYi; Shen, ZeXiang; Kuo, Jer-Lai

    2009-11-24

    The structural, electronic, and vibrational properties of the free finite carbon chains and those encapsulated inside carbon nanotubes (CNTs) are studied by density functional theory calculations. The end effect and chain symmetry are found to play key roles in deciding the structural characteristics of the free finite carbon chains based on the parity of the carbon numbers. Due to the potential interaction between the carbon chains and CNTs, the electrons of the chain-CNT systems will redistribute, and some charges may transfer to the inner carbon chains from CNTs. We suggest that the attractive potential of chain atoms inside CNTs could be the driving force for formation of the linear carbon inside CNTs. Unexpectedly, we find that inside CNTs the carbon chains with even-numbered carbons present almost constant bond length alternation, which is independent of the chain length. This trend of the even-numbered carbon chains in CNTs helps to explain the universal experimental observation that the Raman peaks from chains in CNTs are within 1820-1860 cm(-1).

  8. Finite-Volume QED Corrections to Decay Amplitudes in Lattice QCD

    CERN Document Server

    Lubicz, V.; Sachrajda, C.T.; Sanfilippo, F.; Simula, S.; Tantalo, N.

    2017-01-01

    We demonstrate that the leading and next-to-leading finite-volume effects in the evaluation of leptonic decay widths of pseudoscalar mesons at $O(\\alpha)$ are universal, i.e. they are independent of the structure of the meson. This is analogous to a similar result for the spectrum but with some fundamental differences, most notably the presence of infrared divergences in decay amplitudes. The leading non-universal, structure-dependent terms are of $O(1/L^2)$ (compared to the $O(1/L^3)$ leading non-universal corrections in the spectrum). We calculate the universal finite-volume effects, which requires an extension of previously developed techniques to include a dependence on an external three-momentum (in our case, the momentum of the final state lepton). The result can be included in the strategy proposed in Ref.\\,\\cite{Carrasco:2015xwa} for using lattice simulations to compute the decay widths at $O(\\alpha)$, with the remaining finite-volume effects starting at order $O(1/L^2)$. The methods developed in this...

  9. Finite element analysis of tibial fractures

    DEFF Research Database (Denmark)

    Wong, Christian Nai En; Mikkelsen, Mikkel Peter W; Hansen, Leif Berner

    2010-01-01

    INTRODUCTION: Fractures of the tibial shaft are relatively common injuries. There are indications that tibial shaft fractures share characteristics in terms of site, type and local fracture mechanisms. In this study, we aimed to set up a mathematical, computer-based model using finite element...... of bony healing. The biomechanical results are the basis for fracture healing, biomechanical fall analysis and stability analysis of osteosynthesis. MATERIAL AND METHODS: A finite element model of the bony part of the lower leg was generated on the basis of computed tomography data from the Visible Human...... Project. The data consisted of 21,219 3D elements with a cortical shell and a trabecular core. Three types of load of torsion, a direct lateral load and axial compression were applied. RESULTS: The finite element linear static analysis resulted in relevant fracture localizations and indicated relevant...

  10. Centralizers in simple locally finite groups

    Directory of Open Access Journals (Sweden)

    Mahmut Kuzucuoğlu

    2013-03-01

    Full Text Available This is a survey article on centralizers of finitesubgroups in locally finite, simple groups or LFS-groups as wewill call them. We mention some of the open problems aboutcentralizers of subgroups in LFS-groups and applications of theknown information about the centralizers of subgroups to thestructure of the locally finite group. We also prove thefollowing: Let $G$ be a countably infinite non-linear LFS-groupwith a Kegel sequence $mathcal{K}={(G_i,N_i | iinmathbf{N} }$. If there exists an upper bound for ${ |N_i| |iin mathbf{N} }$, then for any finite semisimplesubgroup $F$ in $G$ the subgroup $C_G(F$ has elements oforder $p_i$ for infinitely many distinct prime $p_i$. Inparticular $C_G(F$ is an infinite group. This answers Hartley'squestion provided that there exists a bound on ${ |N_i| | iin mathbf{N}$.

  11. Geometrically unfitted finite element methods and applications

    CERN Document Server

    Burman, Erik; Larson, Mats; Olshanskii, Maxim

    2017-01-01

    This book provides a snapshot of the state of the art of the rapidly evolving field of integration of geometric data in finite element computations. The contributions to this volume, based on research presented at the UCL workshop on the topic in January 2016, include three review papers on core topics such as fictitious domain methods for elasticity, trace finite element methods for partial differential equations defined on surfaces, and Nitsche’s method for contact problems. Five chapters present original research articles on related theoretical topics, including Lagrange multiplier methods, interface problems, bulk-surface coupling, and approximation of partial differential equations on moving domains. Finally, two chapters discuss advanced applications such as crack propagation or flow in fractured poroelastic media. This is the first volume that provides a comprehensive overview of the field of unfitted finite element methods, including recent techniques such as cutFEM, traceFEM, ghost penalty, and aug...

  12. Essentially finitely indecomposable QTAG-Modules

    Directory of Open Access Journals (Sweden)

    Alveera Mehdi

    2016-01-01

    Full Text Available A right module $M$ over an associative ring with unity is a $QTAG$-module if every finitely generated submodule of any homomorphic image of $M$ is a direct sum of uniserial modules. There are many fascinating results related to these modules and essentially indecomposable modules are extensively researched. Motivated by these modules we generalize them as essentially finitely indecomposable modules whose every direct decomposition $M=\\bigoplus\\limits_{k\\in I} M_k$ implies that there exists a positive integer $n$ such that $H_n(M_i=0$ for all $M_i$'s except for a finite number of $M_i$'s. Here we investigate these modules and their relationship with $HT$-modules. The cases when the modules are not $HT$-modules are especially highlighted.

  13. Shear sum rules at finite chemical potential

    Science.gov (United States)

    David, Justin R.; Jain, Sachin; Thakur, Somyadip

    2012-03-01

    We derive sum rules which constrain the spectral density corresponding to the retarded propagator of the T xy component of the stress tensor for three gravitational duals. The shear sum rule is obtained for the gravitational dual of the mathcal{N} = {4} Yang-Mills, theory of the M2-branes and M5-branes all at finite chemical potential. We show that at finite chemical potential there are additional terms in the sum rule which involve the chemical potential. These modifications are shown to be due to the presence of scalars in the operator product expansion of the stress tensor which have non-trivial vacuum expectation values at finite chemical potential.

  14. Visualizing higher order finite elements. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, David C; Pebay, Philippe Pierre

    2005-11-01

    This report contains an algorithm for decomposing higher-order finite elements into regions appropriate for isosurfacing and proves the conditions under which the algorithm will terminate. Finite elements are used to create piecewise polynomial approximants to the solution of partial differential equations for which no analytical solution exists. These polynomials represent fields such as pressure, stress, and momentum. In the past, these polynomials have been linear in each parametric coordinate. Each polynomial coefficient must be uniquely determined by a simulation, and these coefficients are called degrees of freedom. When there are not enough degrees of freedom, simulations will typically fail to produce a valid approximation to the solution. Recent work has shown that increasing the number of degrees of freedom by increasing the order of the polynomial approximation (instead of increasing the number of finite elements, each of which has its own set of coefficients) can allow some types of simulations to produce a valid approximation with many fewer degrees of freedom than increasing the number of finite elements alone. However, once the simulation has determined the values of all the coefficients in a higher-order approximant, tools do not exist for visual inspection of the solution. This report focuses on a technique for the visual inspection of higher-order finite element simulation results based on decomposing each finite element into simplicial regions where existing visualization algorithms such as isosurfacing will work. The requirements of the isosurfacing algorithm are enumerated and related to the places where the partial derivatives of the polynomial become zero. The original isosurfacing algorithm is then applied to each of these regions in turn.

  15. Electron–phonon coupling from finite differences

    Science.gov (United States)

    Monserrat, Bartomeu

    2018-02-01

    The interaction between electrons and phonons underlies multiple phenomena in physics, chemistry, and materials science. Examples include superconductivity, electronic transport, and the temperature dependence of optical spectra. A first-principles description of electron–phonon coupling enables the study of the above phenomena with accuracy and material specificity, which can be used to understand experiments and to predict novel effects and functionality. In this topical review, we describe the first-principles calculation of electron–phonon coupling from finite differences. The finite differences approach provides several advantages compared to alternative methods, in particular (i) any underlying electronic structure method can be used, and (ii) terms beyond the lowest order in the electron–phonon interaction can be readily incorporated. But these advantages are associated with a large computational cost that has until recently prevented the widespread adoption of this method. We describe some recent advances, including nondiagonal supercells and thermal lines, that resolve these difficulties, and make the calculation of electron–phonon coupling from finite differences a powerful tool. We review multiple applications of the calculation of electron–phonon coupling from finite differences, including the temperature dependence of optical spectra, superconductivity, charge transport, and the role of defects in semiconductors. These examples illustrate the advantages of finite differences, with cases where semilocal density functional theory is not appropriate for the calculation of electron–phonon coupling and many-body methods such as the GW approximation are required, as well as examples in which higher-order terms in the electron–phonon interaction are essential for an accurate description of the relevant phenomena. We expect that the finite difference approach will play a central role in future studies of the electron–phonon interaction.

  16. Declines of greater and lesser scaup populations: issues, hypotheses, and research needs

    Science.gov (United States)

    Austin, J.E.; Afton, A.D.; Anderson, M.G.; Clark, R.G.; Custer, Christine M.; Lawrence, J.; Pollard, J.B.; Ringelman, J.K.

    2000-01-01

    The population estimate for greater (Aythya marila) and lesser (Aythya affinis) scaup (combined) has declined dramatically since the early 1980s to record lows in 1998. The 1998 estimate of 3.47 million scaup is far below the goal of 6.3 million set in the North American Waterfowl Management Plan (NAWMP), causing concern among biologists and hunters. We summarize issues of concern, hypotheses for factors contributing to the population decline, and research and management needs recommended by participants of the Scaup Workshop, held in September 1999. We believe that contaminants, lower female survival, and reduced recruitment due to changes in food resources or breeding-ground habitats are primary factors contributing to the decline. These factors are not mutually exclusive but likely interact across seasons. Workshop participants identified seven action items. We need to further delineate where declines in breeding populations have occurred, with a primary focus on the western Canadian boreal forest, where declines appear to be most pronounced. Productivity in various areas and habitats throughout the breeding range needs to be assessed by conducting retrospective analyses of existing data and by intensive field studies at broad and local scales. Annual and seasonal survival rates need to be determined in order to assess the role of harvest or natural mortality. Effects of contaminants on reproduction, female body condition, and behavior must be investigated. Use, distribution, and role of food resources relative to body condition and reproduction need to be examined to better understand seasonal dynamics of nutrient reserves and the role in reproductive success. Affiliations among breeding, migration, and wintering areas must be assessed in order to understand differential exposure to harvest or contaminants, and differential reproductive success and recruitment. Biologists and agencies need to gather and improve information needed to manage greater and lesser

  17. Dopamine in the Brain: Hypothesizing Surfeit or Deficit Links to Reward and Addiction.

    Science.gov (United States)

    Blum, Kenneth; Thanos, Peter K; Oscar-Berman, Marlene; Febo, Marcelo; Baron, David; Badgaiyan, Rajendra D; Gardner, Eliot; Demetrovics, Zsolt; Fahlke, Claudia; Haberstick, Brett C; Dushaj, Kristina; Gold, Mark S

    Recently there has been debate concerning the role of brain dopamine in reward and addiction. David Nutt and associates eloquently proposed that dopamine (DA) may be central to psycho stimulant dependence and some what important for alcohol, but not important for opiates, nicotine or even cannabis. Others have also argued that surfeit theories can explain for example cocaine seeking behavior as well as non-substance-related addictive behaviors. It seems prudent to distinguish between what constitutes "surfeit" compared to" deficit" in terms of short-term (acute) and long-term (chronic) brain reward circuitry responsivity. In an attempt to resolve controversy regarding the contributions of mesolimbic DA systems to reward, we review the three main competing explanatory categories: "liking", "learning", and "wanting". They are (a) the hedonic impact -liking reward, (b) the ability to predict rewarding effects-learning and (c) the incentive salience of reward-related stimuli -wanting. In terms of acute effects, most of the evidence seems to favor the "surfeit theory". Due to preferential dopamine release at mesolimbic-VTA-caudate-accumbens loci most drugs of abuse and Reward Deficiency Syndrome (RDS) behaviors have been linked to heightened feelings of well-being and hyperdopaminergic states.The "dopamine hypotheses" originally thought to be simple, is now believed to be quite complex and involves encoding the set point of hedonic tone, encoding attention, reward expectancy, and incentive motivation. Importantly, Willuhn et al. shows that in a self-administration paradigm, (chronic) excessive use of cocaine is caused by decreased phasic dopamine signaling in the striatum. In terms of chronic addictions, others have shown a blunted responsivity at brain reward sites with food, nicotine, and even gambling behavior. Finally, we are cognizant of the differences in dopaminergic function as addiction progresses and argue that relapse may be tied to dopamine deficiency

  18. Systemic Microgravity Response: Utilizing GeneLab to Develop Hypotheses for Spaceflight Risks

    Science.gov (United States)

    Beheshti, Afshin; Fogle, Homer; Galazka, Jonathan; Kidane, Yared; Chakravarty, Kaushik; Berrios, Daniel C.; Costes, Sylvain V.

    2017-01-01

    Biological risks associated with microgravity is a major concern for space travel. Although determination of risk has been a focus for NASA research, data examining systemic (i.e., multi- or pan-tissue) responses to space flight are sparse. The overall goal of our work is to identify potential master regulators responsible for such responses to microgravity conditions. To do this we utilized the NASA GeneLab database which contains a wide array of omics experiments, including data from: 1) different flight conditions (space shuttle (STS) missions vs. International Space Station (ISS); 2) different tissues; and 3) different types of assays that measure epigenetic, transcriptional, and protein expression changes. We have performed meta-analysis identifying potential master regulators involved with systemic responses to microgravity. The analysis used 7 different murine and rat data sets, examining the following tissues: liver, kidney, adrenal gland, thymus, mammary gland, skin, and skeletal muscle (soleus, extensor digitorum longus, tibialis anterior, quadriceps, and gastrocnemius). Using a systems biology approach, we were able to determine that p53 and immune related pathways appear central to pan-tissue microgravity responses. Evidence for a universal response in the form of consistency of change across tissues in regulatory pathways was observed in both STS and ISS experiments with varying durations; while degree of change in expression of these master regulators varied across species and strain, some change in these master regulators was universally observed. Interestingly, certain skeletal muscle (gastrocnemius and soleus) show an overall down-regulation in these genes, while in other types (extensor digitorum longus, tibialis anterior and quadriceps) they are up-regulated, suggesting certain muscle tissues may be compensating for atrophy responses caused by microgravity. Studying these organtissue-specific perturbations in molecular signaling networks, we

  19. Finite length thermal equilibria of a pure electron plasma column

    International Nuclear Information System (INIS)

    Prasad, S.A.; O'Neil, T.M.

    1979-01-01

    The electrons of a pure electron plasma may be in thermal equilibrium with each other and still be confined by static magnetic and electric fields. Since the electrons make a significant contribution to the electric field, only certain density profiles are consistent with Poisson's equation. The class of such distributions for a finite length cylindrical column is investigated. In the limit where the Debye length is small compared with the dimensions of the column, the density is essentially constant out to some surface of revolution and then falls off abruptly. The falloff in density is a universal function when measured along the local normal to the surface of revolution and scaled in terms of the Debye length. The solution for the shape of the surface of revolution is simplified by passage to the limit of zero Debye length

  20. Finite temperature holographic duals of 2-dimensional BCFTs

    Science.gov (United States)

    Estes, J.

    2015-07-01

    We consider holographic duals of 2-dimensional conformal field theories in the presence of a boundary, interface, defect and/or junction, referred to collectively as BCFTs. In general, the presence of a boundary reduces the SO(2, 2) conformal symmetry to SO(2, 1) and the dual geometry is realized as a warped product of the form , where is not compact. In particular, it will contain points where the warp factor of the AdS 2 space diverges, leading to asymptotically AdS 3 regions. We show that the AdS 2 space-time may always be replaced with an AdS 2-"black-hole" space-time. We argue the resulting geometry describes the BCFT at finite temperature. To motivate this claim, we compute the entanglement entropy holographically for a segment centered around the defect or ending on the boundary and find agreement with a known universal formula.

  1. Finite continuum quasi distributions from lattice QCD

    Science.gov (United States)

    Monahan, Christopher; Orginos, Kostas

    2018-03-01

    We present a new approach to extracting continuum quasi distributions from lattice QCD. Quasi distributions are defined by matrix elements of a Wilson-line operator extended in a spatial direction, evaluated between nucleon states at finite momentum. We propose smearing this extended operator with the gradient flow to render the corresponding matrix elements finite in the continuum limit. This procedure provides a nonperturbative method to remove the power-divergence associated with the Wilson line and the resulting matrix elements can be directly matched to light-front distributions via perturbation theory.

  2. Virtual photon spectra for finite nuclei

    International Nuclear Information System (INIS)

    Wolynec, E.; Martins, M.N.

    1988-01-01

    The experimental results of an isochromat of the virtual photon spectrum, obtained by measuring the number of ground-state protons emitted by the 16.28 MeV isobaric analogue state in 90 Zr as a function of electron incident energy in the range 17-105 MeV, are compared with the values predicted by a calculation of the E1 DWBA virtual photon spectra for finite nuclei. It is found that the calculations are in excellent agreement with the experimental results. The DWBA virtual photon spectra for finite nuclei for E2 and M1 multipoles are also assessed. (author) [pt

  3. Finite elements for analysis and design

    CERN Document Server

    Akin, J E; Davenport, J H

    1994-01-01

    The finite element method (FEM) is an analysis tool for problem-solving used throughout applied mathematics, engineering, and scientific computing. Finite Elements for Analysis and Design provides a thoroughlyrevised and up-to-date account of this important tool and its numerous applications, with added emphasis on basic theory. Numerous worked examples are included to illustrate the material.Key Features* Akin clearly explains the FEM, a numerical analysis tool for problem-solving throughout applied mathematics, engineering and scientific computing* Basic theory has bee

  4. Finite W-algebras and intermediate statistics

    International Nuclear Information System (INIS)

    Barbarin, F.; Ragoucy, E.; Sorba, P.

    1994-09-01

    New realizations of finite W-algebras are constructed by relaxing the usual conditions. Then finite W-algebras are recognized in the Heisenberg quantization recently proposed by Leinaas and Myrheim, for a system of two identical particles in d dimensions. As the anyonic parameter is directly associated to the W-algebra involved in the d=1 case, it is natural to consider that the W-algebra framework is well adapted for a possible generalization of the anyon statistics. (author). 13 refs

  5. Quadrature representation of finite element variational forms

    DEFF Research Database (Denmark)

    Ølgaard, Kristian Breum; Wells, Garth N.

    2012-01-01

    This chapter addresses the conventional run-time quadrature approach for the numerical integration of local element tensors associated with finite element variational forms, and in particular automated optimizations that can be performed to reduce the number of floating point operations. An alter......This chapter addresses the conventional run-time quadrature approach for the numerical integration of local element tensors associated with finite element variational forms, and in particular automated optimizations that can be performed to reduce the number of floating point operations...

  6. The Finite-Surface Method for incompressible flow: a step beyond staggered grid

    Science.gov (United States)

    Hokpunna, Arpiruk; Misaka, Takashi; Obayashi, Shigeru

    2017-11-01

    We present a newly developed higher-order finite surface method for the incompressible Navier-Stokes equations (NSE). This method defines the velocities as a surface-averaged value on the surfaces of the pressure cells. Consequently, the mass conservation on the pressure cells becomes an exact equation. The only things left to approximate is the momentum equation and the pressure at the new time step. At certain conditions, the exact mass conservation enables the explicit n-th order accurate NSE solver to be used with the pressure treatment that is two or four order less accurate without loosing the apparent convergence rate. This feature was not possible with finite volume of finite difference methods. We use Fourier analysis with a model spectrum to determine the condition and found that the range covers standard boundary layer flows. The formal convergence and the performance of the proposed scheme is compared with a sixth-order finite volume method. Finally, the accuracy and performance of the method is evaluated in turbulent channel flows. This work is partially funded by a research colloaboration from IFS, Tohoku university and ASEAN+3 funding scheme from CMUIC, Chiang Mai University.

  7. Automated Stock Trading – Developing the Serious Game FSTG to Teach the Topic of Finite State Machines

    Directory of Open Access Journals (Sweden)

    Matthias Christoph Utesch

    2017-02-01

    Full Text Available A new methodology to teach about the topic of Finite State Machines is presented in this paper. For this purpose, nine learning objectives which are classified into the three categories Basics of Finite State Machines, parallels between Finite State Machines and stock trading, and the application of Finite State Machines were developed and implemented into a Serious Game solution. This paper covers the third category about the application of Finite State Machines and its use to create Artificial Intelligence. The learning objectives were determined by using the widely-known Taxonomy of Bloom and integrated into the Serious Game The Finite State Trading Game (FSTG. In this turn-based trading game, the user aims to beat a Non-Player Character by skillfully trading shares while the user faces increasing complexity throughout the game. For the evaluation of the Serious Game approach a pre-test and post-test setting was performed with students of a local upper vocational school class at the Technical University of Munich. The results of the following analysis demonstrated significant progress in terms of the students’ knowledge about Finite State Machines for every tested statement.

  8. Phase transitions in ideal and weakly interacting Bose gases with a finite number of particles confined in a box

    International Nuclear Information System (INIS)

    Wang Jianhui; Ma Yongli

    2009-01-01

    We generalize the scheme to characterize phase transitions of finite systems in a complex temperature plane and approach the classifications of phase transitions in ideal and weakly interacting Bose gases of a finite number of particles, confined in a cubic box of volume L 3 with different boundary conditions. For this finite ideal Bose system, by extending the classification parameters to all regions, we predict that the phase transition for periodic boundary conditions is of second order, while the transition in Dirichlet boundary conditions is of first order. For a weakly interacting Bose gas with periodic boundary conditions, we discuss the effects of finite particle numbers and inter-particle interactions on the nature of the phase transitions. We show that this homogenous weakly interacting Bose gas undergoes a second-order phase transition, which is in accordance with universality arguments for infinite systems. We also discuss the dependence of transition temperature on interaction strengths and particle numbers.

  9. Finite-size scaling of the entanglement entropy of the quantum Ising chain with homogeneous, periodically modulated and random couplings

    International Nuclear Information System (INIS)

    Iglói, Ferenc; Lin, Yu-Cheng

    2008-01-01

    Using free-fermionic techniques we study the entanglement entropy of a block of contiguous spins in a large finite quantum Ising chain in a transverse field, with couplings of different types: homogeneous, periodically modulated and random. We carry out a systematic study of finite-size effects at the quantum critical point, and evaluate subleading corrections both for open and for periodic boundary conditions. For a block corresponding to a half of a finite chain, the position of the maximum of the entropy as a function of the control parameter (e.g. the transverse field) can define the effective critical point in the finite sample. On the basis of homogeneous chains, we demonstrate that the scaling behavior of the entropy near the quantum phase transition is in agreement with the universality hypothesis, and calculate the shift of the effective critical point, which has different scaling behaviors for open and for periodic boundary conditions

  10. Quantum Phase Transition and Universal Dynamics in the Rabi Model.

    Science.gov (United States)

    Hwang, Myung-Joong; Puebla, Ricardo; Plenio, Martin B

    2015-10-30

    We consider the Rabi Hamiltonian, which exhibits a quantum phase transition (QPT) despite consisting only of a single-mode cavity field and a two-level atom. We prove QPT by deriving an exact solution in the limit where the atomic transition frequency in the unit of the cavity frequency tends to infinity. The effect of a finite transition frequency is studied by analytically calculating finite-frequency scaling exponents as well as performing a numerically exact diagonalization. Going beyond this equilibrium QPT setting, we prove that the dynamics under slow quenches in the vicinity of the critical point is universal; that is, the dynamics is completely characterized by critical exponents. Our analysis demonstrates that the Kibble-Zurek mechanism can precisely predict the universal scaling of residual energy for a model without spatial degrees of freedom. Moreover, we find that the onset of the universal dynamics can be observed even with a finite transition frequency.

  11. On p-supersolvability of finite groups

    Indian Academy of Sciences (India)

    Supersolvability; p-nilpotency; weakly τ-embedded subgroups. 2010 Mathematics Subject Classification. 20D10, 20D20. 1. Introduction. Throughout the paper, all groups are finite. Recall that a subgroup H of a group G is said to permute with a subgroup ...

  12. Finite difference order doubling in two dimensions

    Energy Technology Data Exchange (ETDEWEB)

    Killingbeck, John P [Mathematics Centre, University of Hull, Hull HU6 7RX (United Kingdom); Jolicard, Georges [Universite de Franche-Comte, Institut Utinam (UMR CNRS 6213), Observatoire de Besancon, 41 bis Avenue de l' Observatoire, BP1615, 25010 Besancon cedex (France)

    2008-03-28

    An order doubling process previously used to obtain eighth-order eigenvalues from the fourth-order Numerov method is applied to the perturbed oscillator in two dimensions. A simple method of obtaining high order finite difference operators is reported and an odd parity boundary condition is found to be effective in facilitating the smooth operation of the order doubling process.

  13. Flexural vibrations of finite composite poroelastic cylinders

    Indian Academy of Sciences (India)

    infinite hollow poroelastic cylinders. Axially symmetric vibrations of finite composite poroe- lastic cylinders that are bonded end to end are investigated by Shah & Tajuddin (2009). The analysis of the flexural vibrations in cylindrical structures has wide applications in the field of acoustics structural design and Biomechanics, ...

  14. Finite Algorithms for Robust Linear Regression

    DEFF Research Database (Denmark)

    Madsen, Kaj; Nielsen, Hans Bruun

    1990-01-01

    The Huber M-estimator for robust linear regression is analyzed. Newton type methods for solution of the problem are defined and analyzed, and finite convergence is proved. Numerical experiments with a large number of test problems demonstrate efficiency and indicate that this kind of approach may...

  15. ∗-supplemented subgroups of finite groups

    Indian Academy of Sciences (India)

    complemented in G. In 1998, Ballester-Bolinches and Pedraza-Aguilera [2] introduced. S-quasinormally embedded ... concept of M-supplemented subgroups and characterized the structure of finite groups by ... A subgroup H of a group G is said to be M∗-supplemented in G if there exists a subgroup. K of G such that G = HK ...

  16. A Note on Powers in Finite Fields

    Science.gov (United States)

    Aabrandt, Andreas; Hansen, Vagn Lundsgaard

    2016-01-01

    The study of solutions to polynomial equations over finite fields has a long history in mathematics and is an interesting area of contemporary research. In recent years, the subject has found important applications in the modelling of problems from applied mathematical fields such as signal analysis, system theory, coding theory and cryptology. In…

  17. The Finite Lamplighter Groups: A Guided Tour

    Science.gov (United States)

    Siehler, Jacob A.

    2012-01-01

    In this article, we present a family of finite groups, which provide excellent examples of the basic concepts of group theory. To work out the center, conjuagacy classes, and commutators of these groups, all that's required is a bit of linear algebra.

  18. Finite element analysis of photonic crystal fibers

    NARCIS (Netherlands)

    Uranus, H.P.; Hoekstra, Hugo; van Groesen, Embrecht W.C.

    2005-01-01

    A finite-element-based vectorial optical mode solver, furnished with Bayliss-Gunzburger-Turkel-like transparent boundary conditions, is used to rigorously analyze photonic crystal fibers (PCFs). Both the real and imaginary part of the modal indices can be computed in a relatively small computational

  19. Finite element simulation of asphalt fatigue testing

    DEFF Research Database (Denmark)

    Ullidtz, Per; Kieler, Thomas Lau; Kargo, Anders

    1997-01-01

    damage mechanics.The paper describes how continuum damage mechanics may be used with a finite element program to explain the progressive deterioration of asphalt mixes under laboratory fatigue testing. Both constant stress and constant strain testing are simulated, and compared to the actual results from...

  20. Legendre Elliptic Curves over Finite Fields

    NARCIS (Netherlands)

    Auer, Roland; Top, Jakob

    2002-01-01

    We show that every elliptic curve over a finite field of odd characteristic whose number of rational points is divisible by 4 is isogenous to an elliptic curve in Legendre form, with the sole exception of a minimal respectively maximal elliptic curve. We also collect some results concerning the

  1. On partially saturated formations of finite groups

    International Nuclear Information System (INIS)

    Ballester-Bolinches, Adolfo; Calvo, Clara; Shemetkov, L A

    2007-01-01

    Various types of partially saturated formations and connections between them are considered. It is shown that partially saturated formations can be characterized as classes of finite groups with generalized central series. A theorem on the decomposition of an FG-module into a sum of two submodules with special properties is proved. Bibliography: 26 titles.

  2. Thermoelectric properties of finite graphene antidot lattices

    DEFF Research Database (Denmark)

    Gunst, Tue; Markussen, Troels; Jauho, Antti-Pekka

    2011-01-01

    We present calculations of the electronic and thermal transport properties of graphene antidot lattices with a finite length along the transport direction. The calculations are based on the π-tight-binding model and the Brenner potential. We show that both electronic and thermal transport...

  3. The geometry of finite equilibrium sets

    DEFF Research Database (Denmark)

    Balasko, Yves; Tvede, Mich

    2009-01-01

    We investigate the geometry of finite datasets defined by equilibrium prices, income distributions, and total resources. We show that the equilibrium condition imposes no restrictions if total resources are collinear, a property that is robust to small perturbations. We also show that the set...

  4. Finite element modelling of solidification phenomena

    Indian Academy of Sciences (India)

    The process of solidification process is complex in nature and the simulation of such process is required in industry before it is actually undertaken. Finite element method is used to simulate the heat transfer process accompanying the solidification process. The metal and the mould along with the air gap formation is ...

  5. Finite-size effects from giant magnons

    Energy Technology Data Exchange (ETDEWEB)

    Arutyunov, Gleb [Institute for Theoretical Physics and Spinoza Institute, Utrecht University, 3508 TD Utrecht (Netherlands)]. E-mail: g.arutyunov@phys.uu.nl; Frolov, Sergey [Max-Planck-Institut fuer Gravitationsphysik, Albert-Einstein-Institut, Am Muehlenberg 1, D-14476 Potsdam (Germany)]. E-mail: frolovs@aei.mpg.de; Zamaklar, Marija [Max-Planck-Institut fuer Gravitationsphysik, Albert-Einstein-Institut, Am Muehlenberg 1, D-14476 Potsdam (Germany)]. E-mail: marzam@aei.mpg.de

    2007-08-27

    In order to analyze finite-size effects for the gauge-fixed string sigma model on AdS{sub 5}xS{sup 5}, we construct one-soliton solutions carrying finite angular momentum J. In the infinite J limit the solutions reduce to the recently constructed one-magnon configuration of Hofman and Maldacena. The solutions do not satisfy the level-matching condition and hence exhibit a dependence on the gauge choice, which however disappears as the size J is taken to infinity. Interestingly, the solutions do not conserve all the global charges of the psu(2,2-vertical bar4) algebra of the sigma model, implying that the symmetry algebra of the gauge-fixed string sigma model is different from psu(2,2-vertical bar4) for finite J, once one gives up the level-matching condition. The magnon dispersion relation exhibits exponential corrections with respect to the infinite J solution. We also find a generalisation of our one-magnon configuration to a solution carrying two charges on the sphere. We comment on the possible implications of our findings for the existence of the Bethe ansatz describing the spectrum of strings carrying finite charges.

  6. The Finite Embeddability Property for Residuated Groupoids

    Czech Academy of Sciences Publication Activity Database

    Haniková, Zuzana; Horčík, Rostislav

    2014-01-01

    Roč. 72, č. 1 (2014), s. 1-13 ISSN 0002-5240 R&D Projects: GA ČR GAP202/11/1632 Institutional support: RVO:67985807 Keywords : residuated groupoid * distributive lattice * finite embeddability property Subject RIV: BA - General Mathematics Impact factor: 0.442, year: 2014

  7. Adsorption of Lithium on Finite Graphitic Clusters

    DEFF Research Database (Denmark)

    Martinez, Jose Ignacio; Cabria, I.; Lopez, M.J.

    2009-01-01

    The apparent discrepancies between density functional (DFT) and Moller-Plesset (MP2) calculations for the interaction of lithium with graphene recently pointed out by Ferre-Vilaplana (J. Phys. Chem. C 2008, 112, 3998) are discussed. In his calculations, this author used a finite coronene cluster, C...

  8. Fast finite elements for surgery simulation

    DEFF Research Database (Denmark)

    Bro-Nielsen, Morten

    1997-01-01

    This paper discusses volumetric deformable models for modeling human body parts and organs in surgery simulation systems. These models are built using finite element models for linear elastic materials. To achieve real-time response condensation has been applied to the system stiffness matrix...

  9. Finite Feedback Cycling in Structural Equation Models

    Science.gov (United States)

    Hayduk, Leslie A.

    2009-01-01

    In models containing reciprocal effects, or longer causal loops, the usual effect estimates assume that any effect touching a loop initiates an infinite cycling of effects around that loop. The real world, in contrast, might permit only finite feedback cycles. I use a simple hypothetical model to demonstrate that if the world permits only a few…

  10. Galerkin finite element methods for wave problems

    Indian Academy of Sciences (India)

    these methods. Keywords. hp-Finite element method; continuous Galerkin methods; wave solutions; Gibbs' phenomenon. 1. Introduction. Galerkin methods belong to the class of solution methods for PDEs where the solution residue is minimized giving rise to the well-known weak formulation of problems. In this approach,.

  11. Equivalent drawbead model in finite element simulations

    NARCIS (Netherlands)

    Carleer, Bart D.; Carleer, B.D.; Meinders, Vincent T.; Huetink, Han; Lee, J.K.; Kinzel, G.L.; Wagoner, R.

    1996-01-01

    In 3D simulations of the deep drawing process the drawbead geometries are seldom included. Therefore equivalent drawbeads are used. In order to investigate the drawbead behaviour a 2D plane strain finite element model was used. For verification of this model experiments were performed. The analyses

  12. Effective permittivity of finite inhomogeneous objects

    NARCIS (Netherlands)

    Raghunathan, S.B.; Budko, N.V.

    2010-01-01

    A generalization of the S-parameter retrieval method for finite three-dimensional inhomogeneous objects under arbitrary illumination and observation conditions is presented. The effective permittivity of such objects may be rigorously defined as a solution of a nonlinear inverse scattering problem.

  13. On higher order pyramidal finite elements

    Czech Academy of Sciences Publication Activity Database

    Liu, L.; Davies, K.B.; Křížek, Michal; Guan, L.

    2011-01-01

    Roč. 3, č. 2 (2011), s. 131-140 ISSN 2070-0733 R&D Projects: GA AV ČR(CZ) IAA100190803 Institutional research plan: CEZ:AV0Z10190503 Keywords : pyramidal polynomial basis functions * finite element method * composite elements * three-dimensional mortar elements Subject RIV: BA - General Mathematics Impact factor: 0.750, year: 2011

  14. The circle equation over finite fields

    DEFF Research Database (Denmark)

    Aabrandt, Andreas; Hansen, Vagn Lundsgaard

    2017-01-01

    Interesting patterns in the geometry of a plane algebraic curve C can be observed when the defining polynomial equation is solved over the family of finite fields. In this paper, we examine the case of C the classical unit circle defined by the circle equation x2 + y2 = 1. As a main result, we es...

  15. Restricted Schur polynomials and finite N counting

    International Nuclear Information System (INIS)

    Collins, Storm

    2009-01-01

    Restricted Schur polynomials have been posited as orthonormal operators for the change of basis from N=4 SYM to type IIB string theory. In this paper we briefly expound the relationship between the restricted Schur polynomials and the operators forwarded by Brown, Heslop, and Ramgoolam. We then briefly examine the finite N counting of the restricted Schur polynomials.

  16. A Ring Construction Using Finite Directed Graphs

    Science.gov (United States)

    Bardzell, Michael

    2012-01-01

    In this paper we discuss an interesting class of noncommutative rings which can be constructed using finite directed graphs. This construction also creates a vector space. These structures provide undergraduate students connections between ring theory and graph theory and, among other things, allow them to see a ring unity element that looks quite…

  17. Finite Cycle Gibbs Measures on Permutations of

    Science.gov (United States)

    Armendáriz, Inés; Ferrari, Pablo A.; Groisman, Pablo; Leonardi, Florencia

    2015-03-01

    We consider Gibbs distributions on the set of permutations of associated to the Hamiltonian , where is a permutation and is a strictly convex potential. Call finite-cycle those permutations composed by finite cycles only. We give conditions on ensuring that for large enough temperature there exists a unique infinite volume ergodic Gibbs measure concentrating mass on finite-cycle permutations; this measure is equal to the thermodynamic limit of the specifications with identity boundary conditions. We construct as the unique invariant measure of a Markov process on the set of finite-cycle permutations that can be seen as a loss-network, a continuous-time birth and death process of cycles interacting by exclusion, an approach proposed by Fernández, Ferrari and Garcia. Define as the shift permutation . In the Gaussian case , we show that for each , given by is an ergodic Gibbs measure equal to the thermodynamic limit of the specifications with boundary conditions. For a general potential , we prove the existence of Gibbs measures when is bigger than some -dependent value.

  18. Finiteness of PST self-dual models

    International Nuclear Information System (INIS)

    Del Cima, Oswaldo M.; Piguet, Olivier; Sarandy, Marcelo S.

    2000-12-01

    The Pasti-Sorokin-Tonin model for describing chiral forms is considered at the quantum level. We study the ultraviolet and infrared behaviour of the model in two, four and six dimensions in the framework of algebraic renormalization. The absence of anomalies, as well as the finiteness, up to non-physical renormalizations, are shown in all dimensions analyzed. (author)

  19. Simplicial Finite Elements in Higher Dimensions

    Czech Academy of Sciences Publication Activity Database

    Brandts, J.; Korotov, S.; Křížek, Michal

    2007-01-01

    Roč. 52, č. 3 (2007), s. 251-265 ISSN 0862-7940 R&D Projects: GA ČR GA201/04/1503 Institutional research plan: CEZ:AV0Z10190503 Keywords : n-simplex * finite element method * superconvergence Subject RIV: BA - General Mathematics

  20. Counting Subspaces of a Finite Vector Space

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 15; Issue 11. Counting Subspaces of a Finite Vector Space – 1. Amritanshu Prasad. General Article Volume 15 Issue 11 November 2010 pp 977-987. Fulltext. Click here to view fulltext PDF. Permanent link: