WorldWideScience

Sample records for evolving universe constraints

  1. University Course Timetabling using Constraint Programming

    Directory of Open Access Journals (Sweden)

    Hadi Shahmoradi

    2017-03-01

    Full Text Available University course timetabling problem is a challenging and time-consuming task on the overall structure of timetable in every academic environment. The problem deals with many factors such as the number of lessons, classes, teachers, students and working time, and these are influenced by some hard and soft constraints. The aim of solving this problem is to assign courses and classes to teachers and students, so that the restrictions are held. In this paper, a constraint programming method is proposed to satisfy maximum constraints and expectation, in order to address university timetabling problem. For minimizing the penalty of soft constraints, a cost function is introduced and AHP method is used for calculating its coefficients. The proposed model is tested on department of management, University of Isfahan dataset using OPL on the IBM ILOG CPLEX Optimization Studio platform. A statistical analysis has been conducted and shows the performance of the proposed approach in satisfying all hard constraints and also the satisfying degree of the soft constraints is on maximum desirable level. The running time of the model is less than 20 minutes that is significantly better than the non-automated ones.

  2. GRI: focusing on the evolving violent universe

    DEFF Research Database (Denmark)

    Knodlseder, J.; von Ballmoos, P.; Frontera, F.

    2009-01-01

    The gamma-ray imager (GRI) is a novel mission concept that will provide an unprecedented sensitivity leap in the soft gamma-ray domain by using for the first time a focusing lens built of Laue diffracting crystals. The lens will cover an energy band from 200-1,300 keV with an effective area reach...... processes in the universe....

  3. Language-universal constraints on speech segmentation

    NARCIS (Netherlands)

    Norris, D.; McQueen, J.M.; Cutler, A.; Butterfield, S.; Kearns, R.K.

    2001-01-01

    Two word-spotting experiments are reported that examine whether the Possible-Word Constraint (PWC; Norris, McQueen, Cutler & Butterfield, 1997) is a language-specific or language-universal strategy for the segmentation of continuous speech. The PWC disfavors parses which leave an impossible residue

  4. GRI: focusing on the evolving violent universe

    Science.gov (United States)

    Knödlseder, Jürgen; von Ballmoos, Peter; Frontera, Filippo; Bazzano, Angela; Christensen, Finn; Hernanz, Margarida; Wunderer, Cornelia

    2009-03-01

    The gamma-ray imager (GRI) is a novel mission concept that will provide an unprecedented sensitivity leap in the soft gamma-ray domain by using for the first time a focusing lens built of Laue diffracting crystals. The lens will cover an energy band from 200-1,300 keV with an effective area reaching 600 cm2. It will be complemented by a single reflection multilayer coated mirror, extending the GRI energy band into the hard X-ray regime, down to ˜10 keV. The concentrated photons will be collected by a position sensitive pixelised CZT stack detector. We estimate continuum sensitivities of better than 10 - 7 ph cm - 2s - 1keV - 1 for a 100 ks exposure; the narrow line sensitivity will be better than 3 × 10 - 6 ph cm - 2s - 1 for the same integration time. As focusing instrument, GRI will have an angular resolution of better than 30 arcsec within a field of view of roughly 5 arcmin—an unprecedented achievement in the gamma-ray domain. Owing to the large focal length of 100 m of the lens and the mirror, the optics and detector will be placed on two separate spacecrafts flying in formation in a high elliptical orbit. R&D work to enable the lens focusing technology and to develop the required focal plane detector is currently underway, financed by ASI, CNES, ESA, and the Spanish Ministery of Education and Science. The GRI mission has been proposed as class M mission for ESAs Cosmic Vision 2015-2025 program. GRI will allow studies of particle acceleration processes and explosion physics in unprecedented detail, providing essential clues on the innermost nature of the most violent and most energetic processes in the universe.

  5. Constraints on backreaction in dust universes

    International Nuclear Information System (INIS)

    Raesaenen, Syksy

    2006-01-01

    We study backreaction in dust universes using exact equations which do not rely on perturbation theory, concentrating on theoretical and observational constraints. In particular, we discuss the recent suggestion (Kolb et al 2005 Preprint hep-th/0503117) that superhorizon perturbations could explain present-day accelerated expansion as a useful example which can be ruled out. We note that a backreaction explanation of late-time acceleration will have to involve spatial curvature and subhorizon perturbations

  6. Black hole entropy, universality, and horizon constraints

    International Nuclear Information System (INIS)

    Carlip, Steven

    2006-01-01

    To ask a question about a black hole in quantum gravity, one must restrict initial or boundary data to ensure that a black hole is actually present. For two-dimensional dilaton gravity, and probably a much wider class of theories, I show that the imposition of a 'stretched horizon' constraint modifies the algebra of symmetries at the horizon, allowing the use of conformal field theory techniques to determine the asymptotic density of states. The result reproduces the Bekenstein-Hawking entropy without any need for detailed assumptions about the microscopic theory. Horizon symmetries may thus offer an answer to the problem of universality of black hole entropy

  7. Black hole entropy, universality, and horizon constraints

    Energy Technology Data Exchange (ETDEWEB)

    Carlip, Steven [Department of Physics, University of California, Davis, CA 95616 (United States)

    2006-03-01

    To ask a question about a black hole in quantum gravity, one must restrict initial or boundary data to ensure that a black hole is actually present. For two-dimensional dilaton gravity, and probably a much wider class of theories, I show that the imposition of a 'stretched horizon' constraint modifies the algebra of symmetries at the horizon, allowing the use of conformal field theory techniques to determine the asymptotic density of states. The result reproduces the Bekenstein-Hawking entropy without any need for detailed assumptions about the microscopic theory. Horizon symmetries may thus offer an answer to the problem of universality of black hole entropy.

  8. EVOLVE

    CERN Document Server

    Deutz, André; Schütze, Oliver; Legrand, Pierrick; Tantar, Emilia; Tantar, Alexandru-Adrian

    2017-01-01

    This book comprises nine selected works on numerical and computational methods for solving multiobjective optimization, game theory, and machine learning problems. It provides extended versions of selected papers from various fields of science such as computer science, mathematics and engineering that were presented at EVOLVE 2013 held in July 2013 at Leiden University in the Netherlands. The internationally peer-reviewed papers include original work on important topics in both theory and applications, such as the role of diversity in optimization, statistical approaches to combinatorial optimization, computational game theory, and cell mapping techniques for numerical landscape exploration. Applications focus on aspects including robustness, handling multiple objectives, and complex search spaces in engineering design and computational biology.

  9. Universal constraints on axions from inflation

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Ricardo Z.; Sloth, Martin S. [CP-Origins, Center for Cosmology and Particle Physics Phenomenology,University of Southern Denmark, Campusvej 55, 5230 Odense M (Denmark)

    2014-12-19

    We consider the presence of an axion like particle, σ, with a generic CP violating axial coupling of the form (α σ/f)FF-tilde, where F{sub μν} is the gauge field strength of a generic abelian U(1) gauge group, not necessarily associated with the standard electromagnetism, and f is the decay constant of the axion. It has previously been demonstrated that if the axion is identified with the inflaton, such an interaction can lead to measurable cosmological signatures (non-Gaussian modifications of the curvature perturbation spectrum) depending on the parameter ξ=α σ-dot /(fH). In the present paper we will show that the generation of curvature perturbation at horizon crossing due to the axial coupling has a universal form and remains unmodified in terms of the ξ parameter even if the axion, σ, is not identified with the inflaton. As a consequence, it does not appear to be possible to generate CMB tensor perturbations through this mechanism, larger than the vacuum ones, without violating the observational constraints unless we combine this mechanism with a curvaton or if the σ field becomes heavy and decays during inflation. Even in this last case there are non-trivial constraints coming from the slow-roll evolution of the curvature perturbation on super horizon scales which should be taken into account. We also comment on implications for inflationary models where axions play an important role as, for example, models of natural inflation where more than one axion are included and models where the curvaton is an axion.

  10. The evolving block universe and the meshing together of times.

    Science.gov (United States)

    Ellis, George F R

    2014-10-01

    It has been proposed that spacetime should be regarded as an evolving block universe, bounded to the future by the present time, which continually extends to the future. This future boundary is defined at each time by measuring proper time along Ricci eigenlines from the start of the universe. A key point, then, is that physical reality can be represented at many different scales: hence, the passage of time may be seen as different at different scales, with quantum gravity determining the evolution of spacetime itself at the Planck scale, but quantum field theory and classical physics determining the evolution of events within spacetime at larger scales. The fundamental issue then arises as to how the effective times at different scales mesh together, leading to the concepts of global and local times. © 2014 New York Academy of Sciences.

  11. How universe evolves with cosmological and gravitational constants

    Directory of Open Access Journals (Sweden)

    She-Sheng Xue

    2015-08-01

    Full Text Available With a basic varying space–time cutoff ℓ˜, we study a regularized and quantized Einstein–Cartan gravitational field theory and its domains of ultraviolet-unstable fixed point gir≳0 and ultraviolet-stable fixed point guv≈4/3 of the gravitational gauge coupling g=(4/3G/GNewton. Because the fundamental operators of quantum gravitational field theory are dimension-2 area operators, the cosmological constant is inversely proportional to the squared correlation length Λ∝ξ−2. The correlation length ξ characterizes an infrared size of a causally correlate patch of the universe. The cosmological constant Λ and the gravitational constant G are related by a generalized Bianchi identity. As the basic space–time cutoff ℓ˜ decreases and approaches to the Planck length ℓpl, the universe undergoes inflation in the domain of the ultraviolet-unstable fixed point gir, then evolves to the low-redshift universe in the domain of ultraviolet-stable fixed point guv. We give the quantitative description of the low-redshift universe in the scaling-invariant domain of the ultraviolet-stable fixed point guv, and its deviation from the ΛCDM can be examined by low-redshift (z≲1 cosmological observations, such as supernova Type Ia.

  12. The effects of perceived leisure constraints among Korean university students

    Science.gov (United States)

    Sae-Sook Oh; Sei-Yi Oh; Linda L. Caldwell

    2002-01-01

    This study is based on Crawford, Jackson, and Godbey's model of leisure constraints (1991), and examines the relationships between the influences of perceived constraints, frequency of participation, and health status in the context of leisure-time outdoor activities. The study was based on a sample of 234 Korean university students. This study provides further...

  13. Clique size and network characteristics in hyperlink cinema. Constraints of evolved psychology.

    Science.gov (United States)

    Krems, Jaimie Arona; Dunbar, R I M

    2013-12-01

    Hyperlink cinema is an emergent film genre that seeks to push the boundaries of the medium in order to mirror contemporary life in the globalized community. Films in the genre thus create an interacting network across space and time in such a way as to suggest that people's lives can intersect on scales that would not have been possible without modern technologies of travel and communication. This allows us to test the hypothesis that new kinds of media might permit us to break through the natural cognitive constraints that limit the number and quality of social relationships we can manage in the conventional face-to-face world. We used network analysis to test this hypothesis with data from 12 hyperlink films, using 10 motion pictures from a more conventional film genre as a control. We found few differences between hyperlink cinema films and the control genre, and few differences between hyperlink cinema films and either the real world or classical drama (e.g., Shakespeare's plays). Conversation group size seems to be especially resilient to alteration. It seems that, despite many efficiency advantages, modern media are unable to circumvent the constraints imposed by our evolved psychology.

  14. Universal constraints on axions from inflation

    DEFF Research Database (Denmark)

    Ferreira, R. Z.; Sloth, M. S.

    2014-01-01

    -roll evolution of the curvature perturbation on super horizon scales which should be taken into account. We also comment on implications for inflationary models where axions play an important role as, for example, models of natural inflation where more than one axion are included and models where the curvaton...... that the generation of curvature perturbation at horizon crossing due to the axial coupling has a universal form and remains unmodified in terms of the xi parameter even if the axion, sigma, is not identified with the inflaton. As a consequence, it does not appear to be possible to generate CMB tensor perturbations...

  15. A New Empirical Constraint on the Prevalence of Technological Species in the Universe.

    Science.gov (United States)

    Frank, A; Sullivan, W T

    2016-05-01

    In this article, we address the cosmic frequency of technological species. Recent advances in exoplanet studies provide strong constraints on all astrophysical terms in the Drake equation. Using these and modifying the form and intent of the Drake equation, we set a firm lower bound on the probability that one or more technological species have evolved anywhere and at any time in the history of the observable Universe. We find that as long as the probability that a habitable zone planet develops a technological species is larger than ∼10(-24), humanity is not the only time technological intelligence has evolved. This constraint has important scientific and philosophical consequences. Life-Intelligence-Extraterrestrial life. Astrobiology 2016, 359-362.

  16. Proximate effects of temperature versus evolved intrinsic constraints for embryonic development times among temperate and tropical songbirds

    Science.gov (United States)

    Ton, Riccardo; Martin, Thomas E.

    2017-01-01

    The relative importance of intrinsic constraints imposed by evolved physiological trade-offs versus the proximate effects of temperature for interspecific variation in embryonic development time remains unclear. Understanding this distinction is important because slow development due to evolved trade-offs can yield phenotypic benefits, whereas slow development from low temperature can yield costs. We experimentally increased embryonic temperature in free-living tropical and north temperate songbird species to test these alternatives. Warmer temperatures consistently shortened development time without costs to embryo mass or metabolism. However, proximate effects of temperature played an increasingly stronger role than intrinsic constraints for development time among species with colder natural incubation temperatures. Long development times of tropical birds have been thought to primarily reflect evolved physiological trade-offs that facilitate their greater longevity. In contrast, our results indicate a much stronger role of temperature in embryonic development time than currently thought.

  17. Irreversible Thermodynamics of the Universe: Constraints from Planck Data

    International Nuclear Information System (INIS)

    Saha, Subhajit; Chakraborty, Subenoy; Biswas, Atreyee

    2014-01-01

    The present work deals with irreversible universal thermodynamics. The homogenous and isotropic flat model of the universe is chosen as open thermodynamical system and nonequilibrium thermodynamics comes into picture. For simplicity, entropy flow is considered only due to heat conduction. Further, due to Maxwell-Cattaneo modified Fourier law for nonequilibrium phenomenon, the temperature satisfies damped wave equation instead of heat conduction equation. Validity of generalized second law of thermodynamics (GSLT) has been investigated for universe bounded by apparent or event horizon with cosmic substratum as perfect fluid with constant or variable equation of state or interacting dark species. Finally, we have used three Planck data sets to constrain the thermal conductivity λ and the coupling parameter b 2 . These constraints must be satisfied in order for GSLT to hold for universe bounded by apparent or event horizons

  18. Vision 2040: Evolving the Successful International Space University

    Science.gov (United States)

    Martin, Gary; Marti, Izan Peris; Tlustos, Reinhard; Lorente, Arnau Pons; Panerati, Jocopo; Mensink, Wendy; Sorkhabi, Elbruz; Garcia, Oriol Gasquez; Musilova, Michaela; Pearson, Thomas

    2015-01-01

    Space exploration has always been full of inspiration, innovation, and creativity, with the promise of expanding human civilization beyond Earth. The space sector is currently experiencing rapid change as disruptive technologies, grassroots programs, and new commercial initiatives have reshaped long-standing methods of operation. Throughout the last 28 years, the International Space University (ISU) has been a leading institution for space education, forming international partnerships, and encouraging entrepreneurship in its over 4,000 alumni. In this report, our Vision 2040 team projected the next 25 years of space exploration and analyzed how ISU could remain a leading institution in the rapidly changing industry. Vision 2040 considered five important future scenarios for the space sector: real-time Earth applications, orbital stations, lunar bases, lunar and asteroid mining, and a human presence on Mars. We identified the signals of disruptive change within these scenarios, including underlying driving forces and potential challenges, and derived a set of skills that will be required in the future space industry. Using these skills as a starting point, we proposed strategies in five areas of focus for ISU: the future of the Space Studies Program (SSP), analog missions, outreach, alumni, and startups. We concluded that ISU could become not just an increasingly innovative educational institution, but one that acts as an international organization that drives space commercialization, exploration, innovation, and cooperation.

  19. OBSERVATION OF UNIVERSALITY IN THE GENERALIZED SIMILARITY OF EVOLVING SOLAR WIND TURBULENCE AS SEEN BY ULYSSES

    International Nuclear Information System (INIS)

    Chapman, S. C.; Nicol, R. M.; Leonardis, E.; Kiyani, K.; Carbone, V.

    2009-01-01

    We perform statistical analysis of the fluctuating magnetic field observed in-situ by the Ulysses spacecraft, from the perspective of quantitative characterization of the evolving magnetohydrodynamic (MHD) turbulence. We focus on two successive polar passes around solar minimum which provide extended intervals of quiet, fast solar wind at a range of radial distances and latitudes: the south polar pass of 1994 and the north polar pass of 1995. Fully developed inertial range turbulence has a characteristic statistical similarity property of quantities that characterize the flow, such as the magnetic field components B k (t), so that the pth moment of fluctuations has power-law dependence on scale τ such that k (t + τ) - B k (t)| p > ∼ τ ζ(p) . We instead find a generalized similarity k (t + τ) - B k (t)| p > ∼ g(τ/τ 0 ) ζ(p) consistent with extended self-similarity; and in particular all of these Ulysses observations, from both polar passes, share the same single function g(τ/τ 0 ). If these observations are indeed characteristic of MHD turbulence evolving in-situ, then this quantifies for the first time a key aspect of the universal nature of evolving MHD turbulence in a system of finite size, with implications both for theoretical development, and for our understanding of the evolving solar wind.

  20. The evolving universe and the origin of life the search for our cosmic roots

    CERN Document Server

    Teerikorpi, Pekka; Lehto, Harry; Chernin, Arthur; Byrd, Gene; Lehto, K

    2008-01-01

    Sir Isaac Newton famously said, regarding his discoveries, "If I have seen further it is by standing upon the shoulders of giants." The Evolving Universe and the Origin of Life describes, complete with fascinating biographical details of the thinkers involved, the ascent to the metaphorical shoulders accomplished by the greatest minds in history. For the first time, a single book can take the reader on a journey through the history of the universe as interpreted by the expanding body of knowledge of humankind. From subatomic particles to the protein chains that form life, and expanding in scale to the entire universe, this book covers the science that explains how we came to be. The Evolving Universe and the Origin of Life contains a great breadth of knowledge, from astronomy to physics, from chemistry to biology. It includes over 350 figures that enhance the comprehension of concepts both basic and advanced, and is a non-technical, easy-to-read text at an introductory college level that is ideal for anyone i...

  1. Universe in the theoretical model «Evolving matter»

    Directory of Open Access Journals (Sweden)

    Bazaluk Oleg

    2013-04-01

    Full Text Available The article critically examines modern model of the Universe evolution constructed by efforts of a group of scientists (mathematicians, physicists and cosmologists from the world's leading universities (Oxford and Cambridge Universities, Yale, Columbia, New York, Rutgers and the UC Santa Cruz. The author notes its strengths, but also points to shortcomings. Author believes that this model does not take into account the most important achievements in the field of biochemistry and biology (molecular, physical, developmental, etc., as well as neuroscience and psychology. Author believes that in the construction of model of the Universe evolution, scientists must take into account (with great reservations the impact of living and intelligent matter on space processes. As an example, the author gives his theoretical model "Evolving matter". In this model, he shows not only the general dependence of the interaction of cosmic processes with inert, living and intelligent matter, but also he attempts to show the direct influence of systems of living and intelligent matter on the acceleration of the Universe's expansion.

  2. Future CMB cosmological constraints in a dark coupled universe

    CERN Document Server

    Martinelli, Matteo; Melchiorri, Alessandro; Mena, Olga

    2010-01-01

    Cosmic Microwave Background satellite missions as the on-going Planck experiment are expected to provide the strongest constraints on a wide set of cosmological parameters. Those constraints, however, could be weakened when the assumption of a cosmological constant as the dark energy component is removed. Here we show that it will indeed be the case when there exists a coupling among the dark energy and the dark matter fluids. In particular, the expected errors on key parameters as the cold dark matter density and the angular diameter distance at decoupling are significantly larger when a dark coupling is introduced. We show that it will be the case also for future satellite missions as EPIC, unless CMB lensing extraction is performed.

  3. Constraints on Alternate Universes: Stars and habitable planets with different fundamental constants

    OpenAIRE

    Adams, Fred C.

    2015-01-01

    This paper develops constraints on the values of the fundamental constants that allow universes to be habitable. We focus on the fine structure constant $\\alpha$ and the gravitational structure constant $\\alpha_G$, and find the region in the $\\alpha$-$\\alpha_G$ plane that supports working stars and habitable planets. This work is motivated, in part, by the possibility that different versions of the laws of physics could be realized within other universes. The following constraints are enforce...

  4. Financial Management of Canadian Universities: Adaptive Strategies to Fiscal Constraints

    Science.gov (United States)

    Deering, Darren; Sá, Creso M.

    2014-01-01

    Decreasing government funding and regulated tuition policies have created a financially constrained environment for Canada's universities. The conventional response to such conditions is to cut programme offerings and services in an attempt to lower costs throughout the institution. However, we argue that three Canadian universities have reacted…

  5. Nuclear constraints on the age of the universe

    International Nuclear Information System (INIS)

    Schramm, D.N.

    1982-12-01

    In this paper a review is made of how one can use nuclear physics to put rather stringent limits on the age of the universe and thus the cosmic distance scale. As the other papers in this session have demonstrated there is some disagreement on the distance scale and thus the limits on the age of the universe (if the cosmological constant ν = 0). However, the disagreement is only over the last factor of 2, the basic timescale seems to really be remarkably well agreed upon. The universe is billions of years old - not thousands, not quintillions but bilions of years. That our universe has a finite age is philosophically intriguing. That we can estimate that age to a fair degree of accuracy is truly impressive. No single measurement of the time since the Big Bang gives a specific, unambiguous age. Fortunately, we have at our disposal several methods that together fix the age with surprising precision. In particular, as the other papers show, there are three totally independent techniques for estimating an age and a fourth technique which involves finding consistency of the other three in the framework of the standard Big Bang cosmological model. The three independent methods are: cosmological dynamics, the age of the oldest stars, and radioactive dating. This paper concentrates on the third of the three methods, as well as go into the consistency technique

  6. The evolving organizational structure of academic health centers: the case of the University of Florida.

    Science.gov (United States)

    Barrett, Douglas J

    2008-09-01

    The organizational structures of academic health centers (AHCs) vary widely, but they all exist along a continuum of integration--that is, the degree to which the academic and clinical missions operate under a single administrative and governance structure. This author provides a brief overview of the topic of AHC integration, including the pros and cons of more integrated or less integrated models. He then traces the evolution of the University of Florida (UF) Health Science Center, which was created in the 1950s as a fully integrated AHC and which now operates under a more distributed management and governance model. Starting as a completely integrated AHC, UF's Health Science Center reached a time of maximal nonintegration (or dys-integration) in the late 1990s and at the beginning of this decade. Circumstances are now pushing the expanding clinical and academic enterprises to be more together as they face the challenges of market competition, federal research budget constraints, and reengineering clinical operations to reduce costs, enhance access, and improve quality and patient safety. Although formal organizational integration may not be possible or appropriate for any number of legal or political reasons, the author suggests that AHCs should strive for "functional integration" to be successful in the current turbulent environment.

  7. Lack of evolvability in self-sustaining autocatalytic networks constraints metabolism-first scenarios for the origin of life.

    Science.gov (United States)

    Vasas, Vera; Szathmáry, Eörs; Santos, Mauro

    2010-01-26

    A basic property of life is its capacity to experience Darwinian evolution. The replicator concept is at the core of genetics-first theories of the origin of life, which suggest that self-replicating oligonucleotides or their similar ancestors may have been the first "living" systems and may have led to the evolution of an RNA world. But problems with the nonenzymatic synthesis of biopolymers and the origin of template replication have spurred the alternative metabolism-first scenario, where self-reproducing and evolving proto-metabolic networks are assumed to have predated self-replicating genes. Recent theoretical work shows that "compositional genomes" (i.e., the counts of different molecular species in an assembly) are able to propagate compositional information and can provide a setup on which natural selection acts. Accordingly, if we stick to the notion of replicator as an entity that passes on its structure largely intact in successive replications, those macromolecular aggregates could be dubbed "ensemble replicators" (composomes) and quite different from the more familiar genes and memes. In sharp contrast with template-dependent replication dynamics, we demonstrate here that replication of compositional information is so inaccurate that fitter compositional genomes cannot be maintained by selection and, therefore, the system lacks evolvability (i.e., it cannot substantially depart from the asymptotic steady-state solution already built-in in the dynamical equations). We conclude that this fundamental limitation of ensemble replicators cautions against metabolism-first theories of the origin of life, although ancient metabolic systems could have provided a stable habitat within which polymer replicators later evolved.

  8. Acquisition of the Constraints on "Wanna" Contraction by Advanced Second Language Learners: Universal Grammar and Imperfect Knowledge

    Science.gov (United States)

    Kweon, Soo-Ok; Bley-Vroman, Robert

    2011-01-01

    Contraction of "want to" to "wanna" is subject to constraints that have been related to the operation of Universal Grammar. Contraction appears to be blocked when the trace of an extracted "wh"-word intervenes. Evidence for knowledge of these constraints by young English-speaking children has been taken to show the operation of Universal Grammar…

  9. Constraints on alternate universes: stars and habitable planets with different fundamental constants

    International Nuclear Information System (INIS)

    Adams, Fred C.

    2016-01-01

    This paper develops constraints on the values of the fundamental constants that allow universes to be habitable. We focus on the fine structure constant α and the gravitational structure constant α G , and find the region in the α-α G plane that supports working stars and habitable planets. This work is motivated, in part, by the possibility that different versions of the laws of physics could be realized within other universes. The following constraints are enforced: [A] long-lived stable nuclear burning stars exist, [B] planetary surface temperatures are hot enough to support chemical reactions, [C] stellar lifetimes are long enough to allow biological evolution, [D] planets are massive enough to maintain atmospheres, [E] planets are small enough in mass to remain non-degenerate, [F] planets are massive enough to support sufficiently complex biospheres, [G] planets are smaller in mass than their host stars, and [H] stars are smaller in mass than their host galaxies. This paper delineates the portion of the α-α G plane that satisfies all of these constraints. The results indicate that viable universes—with working stars and habitable planets—can exist within a parameter space where the structure constants α and α G vary by several orders of magnitude. These constraints also provide upper bounds on the structure constants (α,α G ) and their ratio. We find the limit α G /α ∼< 10 −34 , which shows that habitable universes must have a large hierarchy between the strengths of the gravitational force and the electromagnetic force

  10. Constraints on alternate universes: stars and habitable planets with different fundamental constants

    Energy Technology Data Exchange (ETDEWEB)

    Adams, Fred C., E-mail: fca@umich.edu [Physics Department, University of Michigan, 450 Church Street, Ann Arbor, MI 48109 (United States)

    2016-02-01

    This paper develops constraints on the values of the fundamental constants that allow universes to be habitable. We focus on the fine structure constant α and the gravitational structure constant α{sub G}, and find the region in the α-α{sub G} plane that supports working stars and habitable planets. This work is motivated, in part, by the possibility that different versions of the laws of physics could be realized within other universes. The following constraints are enforced: [A] long-lived stable nuclear burning stars exist, [B] planetary surface temperatures are hot enough to support chemical reactions, [C] stellar lifetimes are long enough to allow biological evolution, [D] planets are massive enough to maintain atmospheres, [E] planets are small enough in mass to remain non-degenerate, [F] planets are massive enough to support sufficiently complex biospheres, [G] planets are smaller in mass than their host stars, and [H] stars are smaller in mass than their host galaxies. This paper delineates the portion of the α-α{sub G} plane that satisfies all of these constraints. The results indicate that viable universes—with working stars and habitable planets—can exist within a parameter space where the structure constants α and α{sub G} vary by several orders of magnitude. These constraints also provide upper bounds on the structure constants (α,α{sub G}) and their ratio. We find the limit α{sub G}/α ∼< 10{sup −34}, which shows that habitable universes must have a large hierarchy between the strengths of the gravitational force and the electromagnetic force.

  11. Cosmological constraints on radion evolution in the universal extra dimension model

    International Nuclear Information System (INIS)

    Chan, K. C.; Chu, M.-C.

    2008-01-01

    The constraints on the radion evolution in the universal extra dimension (UED) model from cosmic microwave background (CMB) and Type Ia supernovae (SNe Ia) data are studied. In the UED model, where both the gravity and standard model fields can propagate in the extra dimensions, the evolution of the extra-dimensional volume, the radion, induces variation of fundamental constants. We discuss the effects of variation of the relevant constants in the context of UED for the CMB power spectrum and SNe Ia data. We then use the three-year WMAP data to constrain the radion evolution at z∼1100, and the 2σ constraint on ρ/ρ 0 (ρ is a function of the radion, to be defined in the text) is [-8.8,6.6]x10 -13 yr -1 . The SNe Ia gold sample yields a constraint on ρ/ρ 0 , for redshift between 0 and 1, to be [-4.7,14]x10 -13 yr -1 . Furthermore, the constraints from SNe Ia can be interpreted as bounds on the evolution QCD scale parameter, Λ QCD /Λ QCD,0 , [-1.4,2.8]x10 -11 yr -1 , without reference to the UED model.

  12. The Role of the Jesuit University in the Evolving “Innovation Triangle” of Business, Government, and Academia

    Directory of Open Access Journals (Sweden)

    Roberto Brancatelli

    2016-04-01

    Full Text Available The purpose of this paper is to suggest a role for Jesuit universities to play in the evolving collaboration among business, government, and academia. Specifically, this paper will identify an “innovation triangle” whose aim is the creation of innovative ways to meet the challenges of a global economy. For purposes of the International Association of Jesuit Business Schools 2015 Conference in Montevideo, Uruguay, the subject area is “Jesuit inspiration at the university level: business challenges.” Our methodology consists of evaluating the role of Jesuit universities through the case study of a conference organized by the presenters of this paper. Although not actually held, the conference was scheduled to take place at Unisinos Business School in São Leopoldo, Brazil. Entitled “Doing Brazil in Brazil,” it involved a new structure in which participants were to work alongside government officials, university faculty, and students while exploring the ethical dimensions of foreign investment and business in Brazil. This was to have been done in conjunction with a techpark adjacent to the university.

  13. Axion-like particles: possible hints and constraints from the high-energy Universe

    International Nuclear Information System (INIS)

    Brun, Pierre

    2013-01-01

    The high-energy Universe is potentially a great laboratory for searching new light bosons such as axion-like particles (ALPs). Cosmic sources are indeed the scene of violent phenomena that involve strong magnetic field and/or very long baselines, where the effects of the mixing of photons with ALPs could lead to observable effects. Two examples are archetypal of this fact, that are the Universe opacity to gamma-rays and the imprints of astrophysical magnetic turbulence in the energy spectra of high-energy sources. In the first case, hints for the existence of ALPs can be proposed whereas the second one is used to put constraints on the ALP mass and coupling to photons

  14. Non-universal gaugino mass GUT models in the light of dark matter and LHC constraints

    International Nuclear Information System (INIS)

    Chakrabortty, Joydeep; Mohanty, Subhendra; Rao, Soumya

    2014-01-01

    We perform a comprehensive study of SU(5), SO(10) and E(6) supersymmetric GUT models where the gaugino masses are generated through the F-term breaking vacuum expectation values of the non-singlet scalar fields. In these models the gauginos are non-universal at the GUT scale unlike in the mSUGRA scenario. We discuss the properties of the LSP which is stable and a viable candidate for cold dark matter. We look for the GUT scale parameter space that leads to the the lightest SM like Higgs mass in the range of 122–127 GeV compatible with the observations at ATLAS and CMS, the relic density in the allowed range of WMAP-PLANCK and compatible with other constraints from colliders and direct detection experiments. We scan universal scalar (m 0 G ), trilinear coupling A 0 and SU(3) C gaugino mass (M 3 G ) as the independent free parameters for these models. Based on the gaugino mass ratios at the GUT scale, we classify 25 SUSY GUT models and find that of these only 13 models satisfy the dark matter and collider constraints. Out of these 13 models there is only one model where there is a sizeable SUSY contribution to muon (g−2)

  15. Decision Making and Priority Setting: The Evolving Path Towards Universal Health Coverage.

    Science.gov (United States)

    Paolucci, Francesco; Redekop, Ken; Fouda, Ayman; Fiorentini, Gianluca

    2017-12-01

    Health technology assessment (HTA) is widely viewed as an essential component in good universal health coverage (UHC) decision-making in any country. Various HTA tools and metrics have been developed and refined over the years, including systematic literature reviews (Cochrane), economic modelling, and cost-effectiveness ratios and acceptability curves. However, while the cost-effectiveness ratio is faithfully reported in most full economic evaluations, it is viewed by many as an insufficient basis for reimbursement decisions. Emotional debates about the reimbursement of cancer drugs, orphan drugs, and end-of-life treatments have revealed fundamental disagreements about what should and should not be considered in reimbursement decisions. Part of this disagreement seems related to the equity-efficiency tradeoff, which reflects fundamental differences in priorities. All in all, it is clear that countries aiming to improve UHC policies will have to go beyond the capacity building needed to utilize the available HTA toolbox. Multi-criteria decision analysis (MCDA) offers a more comprehensive tool for reimbursement decisions where different weights of different factors/attributes can give policymakers important insights to consider. Sooner or later, every country will have to develop their own way to carefully combine the results of those tools with their own priorities. In the end, all policymaking is based on a mix of facts and values.

  16. Universality of Planck's constant and a constraint from the absence of ℏ-induced neutrino mixing

    Science.gov (United States)

    Llanes-Estrada, Felipe J.

    2014-03-01

    You have probably often set ℏ = 1 but for what particle? I revisit here the possibility of a non-universal Planck-constant. Anomaly cancellation suggests that all particles in the same family perceive the same ℏ at fixed charges e, gw, gs; the difference between the muon's and the electron's (and thus the first and second families) can be tightly constrained by the muon's anomalous magnetic moment, but constraints are weaker for the third family. Neutrino mixing could have proceeded a priori not only by the Lagrangian neutrino mass-term, but also by the kinetic term if Planck's constant was not equal for all three species. An experimental constraint follows as such contributions, characterized by oscillations proportional to the energy, as opposed to the inverse energy, have been generically analyzed in the past. This provides at the same time support for gauge invariance. On the other hand if ℏ differs among particles while fixing the fine structure constants αem, αs, etc. instead of the charges, it affects the muonic atom puzzle without much constrain from g - 2 . Based on arXiv:1312.3566. Supported by spanish grants FPA2011-27853-C02-01 and CPAN.

  17. Constraints experienced by EFL literature students: A case study from an Algerian university

    Directory of Open Access Journals (Sweden)

    Bouazid, Tayeb

    2010-12-01

    Full Text Available This article investigates the perceptions and experiences of second language reading and comprehension of Arabic-speaking university students in TEFL (Teaching English as a Foreign Language literature classes. In reflecting students’ observations and experiences in a variety of classroom activities, the study attempts to uncover the constraints and challenges students experience and to suggest ways in which these difficulties could be overcome. The findings of the study reveal that lecturers have a significant role to play in helping students overcome barriers to understanding and interpreting literature. Recommendations for improving comprehension and enjoyment in L2 literature studies include the teaching and modelling of appropriate reading strategies that improve critical and analytical thinking skills; teaching and learning within a collaborative learning environment which fosters the development and exploration of ideas; and improving students’ background knowledge relevant to the text being studied.

  18. Planets in other universes: habitability constraints on density fluctuations and galactic structure

    Energy Technology Data Exchange (ETDEWEB)

    Adams, Fred C.; Coppess, Katherine R. [Physics Department, University of Michigan, Ann Arbor, MI 48109 (United States); Bloch, Anthony M., E-mail: fca@umich.edu, E-mail: kcoppess@umich.edu, E-mail: abloch@umich.edu [Mathematics Department, University of Michigan, Ann Arbor, MI 48109 (United States)

    2015-09-01

    Motivated by the possibility that different versions of the laws of physics could be realized within other universes, this paper delineates the galactic structure parameters that allow for habitable planets and revisits constraints on the amplitude Q of the primordial density fluctuations. Previous work indicates that large values of Q lead to galaxies so dense that planetary orbits cannot survive long enough for life to develop. Small values of Q lead to delayed star formation, loosely bound galaxies, and compromised heavy element retention. This work generalizes previous treatments in the following directions: [A] We consider models for the internal structure of the galaxies, including a range of stellar densities, and find the fraction of the resulting galactic real estate that allows for stable, long-lived planetary orbits. [B] For high velocity encounters, we perform a large ensemble of numerical simulations to estimate cross sections for the disruption of planetary orbits due to interactions with passing stars. [C] We consider the background radiation fields produced by the galaxies: if a galaxy is too compact, the night sky seen from a potentially habitable planet can provide more power than the host star. [D] One consequence of intense galactic background radiation fields is that some portion of the galaxy, denoted as the Galactic Habitable Zone, will provide the right flux levels to support habitable planets for essentially any planetary orbit including freely floating bodies (but excluding close-in planets). As the value of Q increases, the fraction of stars in a galaxy that allow for (traditional) habitable planets decreases due to both orbital disruption and the intense background radiation. However, the outer parts of the galaxy always allow for habitable planets, so that the value of Q does not have a well-defined upper limit (due to scattering or radiation constraints). Moreover, some Galactic Habitable Zones are large enough to support more

  19. Planets in other universes: habitability constraints on density fluctuations and galactic structure

    International Nuclear Information System (INIS)

    Adams, Fred C.; Coppess, Katherine R.; Bloch, Anthony M.

    2015-01-01

    Motivated by the possibility that different versions of the laws of physics could be realized within other universes, this paper delineates the galactic structure parameters that allow for habitable planets and revisits constraints on the amplitude Q of the primordial density fluctuations. Previous work indicates that large values of Q lead to galaxies so dense that planetary orbits cannot survive long enough for life to develop. Small values of Q lead to delayed star formation, loosely bound galaxies, and compromised heavy element retention. This work generalizes previous treatments in the following directions: [A] We consider models for the internal structure of the galaxies, including a range of stellar densities, and find the fraction of the resulting galactic real estate that allows for stable, long-lived planetary orbits. [B] For high velocity encounters, we perform a large ensemble of numerical simulations to estimate cross sections for the disruption of planetary orbits due to interactions with passing stars. [C] We consider the background radiation fields produced by the galaxies: if a galaxy is too compact, the night sky seen from a potentially habitable planet can provide more power than the host star. [D] One consequence of intense galactic background radiation fields is that some portion of the galaxy, denoted as the Galactic Habitable Zone, will provide the right flux levels to support habitable planets for essentially any planetary orbit including freely floating bodies (but excluding close-in planets). As the value of Q increases, the fraction of stars in a galaxy that allow for (traditional) habitable planets decreases due to both orbital disruption and the intense background radiation. However, the outer parts of the galaxy always allow for habitable planets, so that the value of Q does not have a well-defined upper limit (due to scattering or radiation constraints). Moreover, some Galactic Habitable Zones are large enough to support more

  20. Astrophysical tests of modified gravity: Constraints from distance indicators in the nearby universe

    International Nuclear Information System (INIS)

    Jain, Bhuvnesh; Vikram, Vinu; Sakstein, Jeremy

    2013-01-01

    We use distance measurements in the nearby universe to carry out new tests of gravity, surpassing other astrophysical tests by over two orders of magnitude for chameleon theories. The three nearby distance indicators—cepheids, tip of the red giant branch (TRGB) stars, and water masers—operate in gravitational fields of widely different strengths. This enables tests of scalar-tensor gravity theories because they are screened from enhanced forces to different extents. Inferred distances from cepheids and TRGB stars are altered (in opposite directions) over a range of chameleon gravity theory parameters well below the sensitivity of cosmological probes. Using published data, we have compared cepheid and TRGB distances in a sample of unscreened dwarf galaxies within 10 Mpc. We use a comparable set of screened galaxies as a control sample. We find no evidence for the order unity force enhancements expected in these theories. Using a two-parameter description of the models (the coupling strength and background field value), we obtain constraints on both the chameleon and symmetron screening scenarios. In particular we show that f(R) models with background field values f R0 above 5 × 10 –7 are ruled out at the 95% confidence level. We also compare TRGB and maser distances to the galaxy NGC 4258 as a second test for larger field values. While there are several approximations and caveats in our study, our analysis demonstrates the power of gravity tests in the local universe. We discuss the prospects for additional improved tests with future observations.

  1. Astrophysical tests of modified gravity: Constraints from distance indicators in the nearby universe

    Energy Technology Data Exchange (ETDEWEB)

    Jain, Bhuvnesh; Vikram, Vinu [Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104 (United States); Sakstein, Jeremy [Department of Applied Mathematics and Theoretical Physics, Cambridge CB3 0WA (United Kingdom)

    2013-12-10

    We use distance measurements in the nearby universe to carry out new tests of gravity, surpassing other astrophysical tests by over two orders of magnitude for chameleon theories. The three nearby distance indicators—cepheids, tip of the red giant branch (TRGB) stars, and water masers—operate in gravitational fields of widely different strengths. This enables tests of scalar-tensor gravity theories because they are screened from enhanced forces to different extents. Inferred distances from cepheids and TRGB stars are altered (in opposite directions) over a range of chameleon gravity theory parameters well below the sensitivity of cosmological probes. Using published data, we have compared cepheid and TRGB distances in a sample of unscreened dwarf galaxies within 10 Mpc. We use a comparable set of screened galaxies as a control sample. We find no evidence for the order unity force enhancements expected in these theories. Using a two-parameter description of the models (the coupling strength and background field value), we obtain constraints on both the chameleon and symmetron screening scenarios. In particular we show that f(R) models with background field values f {sub R0} above 5 × 10{sup –7} are ruled out at the 95% confidence level. We also compare TRGB and maser distances to the galaxy NGC 4258 as a second test for larger field values. While there are several approximations and caveats in our study, our analysis demonstrates the power of gravity tests in the local universe. We discuss the prospects for additional improved tests with future observations.

  2. Local Hi : Constraints on the evolution of the HI content of the Universe

    NARCIS (Netherlands)

    Briggs, FH

    Analyses of QSO absorption lines show that the Hr content has evolved over the redshift range z = 5 to z = 0. The 21-cm line measurements of the z = 0 HI content avoid several biases inherent in the absorption-line technique, such as the influence of evolving dust content in the absorbers, and will

  3. The biological basis of a universal constraint on color naming: cone contrasts and the two-way categorization of colors.

    Science.gov (United States)

    Xiao, Youping; Kavanau, Christopher; Bertin, Lauren; Kaplan, Ehud

    2011-01-01

    Many studies have provided evidence for the existence of universal constraints on color categorization or naming in various languages, but the biological basis of these constraints is unknown. A recent study of the pattern of color categorization across numerous languages has suggested that these patterns tend to avoid straddling a region in color space at or near the border between the English composite categories of "warm" and "cool". This fault line in color space represents a fundamental constraint on color naming. Here we report that the two-way categorization along the fault line is correlated with the sign of the L- versus M-cone contrast of a stimulus color. Moreover, we found that the sign of the L-M cone contrast also accounted for the two-way clustering of the spatially distributed neural responses in small regions of the macaque primary visual cortex, visualized with optical imaging. These small regions correspond to the hue maps, where our previous study found a spatially organized representation of stimulus hue. Altogether, these results establish a direct link between a universal constraint on color naming and the cone-specific information that is represented in the primate early visual system.

  4. τ- μ- e universality in τdecays and constraints on the slepton masses

    International Nuclear Information System (INIS)

    Chankowski, P.H.; Hempfling, R.; Pokorksi, S.

    1994-05-01

    The leptonic τ decays are calculated at the 1-loop level in the Minimal Supersymmetric Standard Model. The deviation from the τ-μ-e universality is studied as a function of the supersymmetric parameters and discussed in the context of the expected improvement of the experimental accuracy. (orig.)

  5. Internal time marker (Q1) of the Cretaceous super chron in the Bay of Bengal - a new age constraint for the oceanic crust evolved between India and Elan Bank

    Science.gov (United States)

    Krishna, K. S.; Ismaiel, M.; Karlapati, S.; Saha, D.; Mishra, J.

    2014-12-01

    Analysis of marine magnetic data of the Bay of Bengal (BOB) led to suggest two different tectonic models for the evolution of lithosphere between India and East Antarctica. The first model explains the presence of M-series (M11 to M0) magnetic anomalies in BOB with a small room leaving for accommodating the crust evolved during the long Cretaceous Magnetic Quiet Period. Second model explains in other way that most part of the crust in BOB was evolved during the quite period together with the possible presence of oldest magnetic chron M1/ M0 in close vicinity of ECMI. It is with this perspective we have reinvestigated the existing and recently acquired magnetic data together with regional magnetic model of BOB for identification of new tectonic constraints, thereby to better understand the evolution of lithosphere. Analysis of magnetic data revealed the presence of spreading anomalies C33 and C34 in the vicinity of 8°N, and internal time marker (Q1) corresponding to the age 92 Ma at 12°N in a corridor between 85°E and Ninetyeast ridges. The new time marker and its location, indeed, become a point of reference and benchmark in BOB for estimating the age of oceanic crust towards ECMI. The magnetic model further reveals the presence of network of fracture zones (FZs) with different orientations. Between 85°E and Ninetyeast ridges, two near N-S FZs, approximately followed 87°E and 89.5°E are found to extend into BOB up to 12°N, from there the FZs reorient in N60°W direction and reach to the continental margin region. Along ECMI two sets of FZs are identified with a northern set oriented in N60°W and southern one in N40°W direction. This suggests that both north and south segments of the ECMI were evolved in two different tectonic settings. The bend in FZs marks the timing (92 Ma) of occurrence of first major plate reorganisation of the Indian Ocean and becomes a very critical constraint for understanding the plate tectonic process in early opening of the

  6. Constraints on the topology of the universe. Extension to general geometries

    Energy Technology Data Exchange (ETDEWEB)

    Vaudrevange, Pascal M. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Case Western Reserve Univ., Cleveland, OH (United States). CERCA and Dept. of Physics; Starkman, Glenn D. [Case Western Reserve Univ., Cleveland, OH (United States). CERCA, ISO and Dept. of Physics; Cornish, Neil J. [Montana State Univ., Bozeman, MT (United States). Dept. of Physics; Spergel, David N. [Princeton Univ., NJ (United States). Dept. of Astrophysical Sciences

    2012-06-15

    We present an update to the search for a non-trivial topology of the universe by searching for matching circle pairs in the cosmic microwave background using the WMAP 7 year data release. We extend the existing bounds to encompass a wider range of possible topologies by searching for matching circle pairs with opening angles 10 {<=}{alpha}{<=}90 and separation angles 11 {<=}{theta}{<=}180 . The extended search reveal two small anomalous regions in the CMB sky. Numerous pairs of well-matched circles are found where both circles pass through one or the other of those regions. As this is not the signature of any known manifold, but is a likely consequence of contamination in those sky regions, we repeat the search excluding circle pairs where both pass through either of the two regions. We then find no statistically significant pairs of matched circles, and so no hints of a non-trivial topology. The absence of matched circles increases the lower limit on the length of the shortest closed null geodesic that self-intersects at our location in the universe (equivalently the injectivity radius at our location) to 98.5% of the diameter of the last scattering surface or approximately 26 Gpc. It extends the limit to any manifolds in which the intersecting arcs of said geodesic form an angle greater than 10 .

  7. Galaxy clusters in simulations of the local Universe: a matter of constraints

    Science.gov (United States)

    Sorce, Jenny G.; Tempel, Elmo

    2018-06-01

    To study the full formation and evolution history of galaxy clusters and their population, high-resolution simulations of the latter are flourishing. However, comparing observed clusters to the simulated ones on a one-to-one basis to refine the models and theories down to the details is non-trivial. The large variety of clusters limits the comparisons between observed and numerical clusters. Simulations resembling the local Universe down to the cluster scales permit pushing the limit. Simulated and observed clusters can be matched on a one-to-one basis for direct comparisons provided that clusters are well reproduced besides being in the proper large-scale environment. Comparing random and local Universe-like simulations obtained with differently grouped observational catalogues of peculiar velocities, this paper shows that the grouping scheme used to remove non-linear motions in the catalogues that constrain the simulations affects the quality of the numerical clusters. With a less aggressive grouping scheme - galaxies still falling on to clusters are preserved - combined with a bias minimization scheme, the mass of the dark matter haloes, simulacra for five local clusters - Virgo, Centaurus, Coma, Hydra, and Perseus - is increased by 39 per cent closing the gap with observational mass estimates. Simulacra are found on average in 89 per cent of the simulations, an increase of 5 per cent with respect to the previous grouping scheme. The only exception is Perseus. Since the Perseus-Pisces region is not well covered by the used peculiar velocity catalogue, the latest release lets us foresee a better simulacrum for Perseus in a near future.

  8. Chaotic universe, Friedmann in the man. III. Ultrarelativistic matter, modified big bang, and constraints on disorder

    Energy Technology Data Exchange (ETDEWEB)

    Marochnik, L.S.

    1981-01-01

    The equations for the correlation functions (derived from the Einstein equations) that describe a statistically chaotic universe are solved in this paper as well as in Paper II. From these solutions the corresponding changes in the standard big bang scenario are determined, and the degree of disorder (that is, constaints on the fluctuation spectrum) which an initially wholly chaotic universe could have retained by the epoch t/sub es/ of light-element nucleosynthesis is established. The time boundaries of the hadron and lepton eras as well as the epochs when electron neutrinos and neutrons become frozen out in weak interactions shift by a factor of up to 1.4 compared with the standard model; the corresponding temperature will drop to 0.88 times the standard value if the rms level of fluctuations averaged over the spectrum during these eras is of order unity. If the fluctuations concentrated in the short-wavelength part of the spectrum have an energy density epsilon<1.5epsilon-bar, then nucleosynthesis in the chaotic cosmology would yield a helium abundance consistent with that observed. If at epoch t/sub es/ the spectral energy density peaks in the long-wave region (lambda/sub max/>>ct/sub es/), the degree of disorder during the nucleosynthesis era would be limited to ..nu..< or =1.76 (here ..nu..approx...integral..Vertical Barc/sub k/Vertical Bar/sup 2/d/sup 3/k; c/sub k/ represents the Fourier amplitude of the metric fluctuations). In particular, Ozernoi's protogalactic vortex perturbations with a wide spectrum (..delta.. = ..delta..k/k> or approx. =4 x 10/sup 3/..cap omega../sup -1/, ..cap omega.. = rho/rho/sub crit/) are compatible with the observed He abundance.

  9. FERMI LARGE AREA TELESCOPE CONSTRAINTS ON THE GAMMA-RAY OPACITY OF THE UNIVERSE

    International Nuclear Information System (INIS)

    Abdo, A. A.; Ackermann, M.; Ajello, M.; Allafort, A.; Bechtol, K.; Berenji, B.; Blandford, R. D.; Bloom, E. D.; Borgland, A. W.; Bouvier, A.; Atwood, W. B.; Baldini, L.; Bellazzini, R.; Ballet, J.; Barbiellini, G.; Baring, M. G.; Bastieri, D.; Baughman, B. M.; Bhat, P. N.; Bonamente, E.

    2010-01-01

    The extragalactic background light (EBL) includes photons with wavelengths from ultraviolet to infrared, which are effective at attenuating gamma rays with energy above ∼10 GeV during propagation from sources at cosmological distances. This results in a redshift- and energy-dependent attenuation of the γ-ray flux of extragalactic sources such as blazars and gamma-ray bursts (GRBs). The Large Area Telescope on board Fermi detects a sample of γ-ray blazars with redshift up to z ∼ 3, and GRBs with redshift up to z ∼ 4.3. Using photons above 10 GeV collected by Fermi over more than one year of observations for these sources, we investigate the effect of γ-ray flux attenuation by the EBL. We place upper limits on the γ-ray opacity of the universe at various energies and redshifts and compare this with predictions from well-known EBL models. We find that an EBL intensity in the optical-ultraviolet wavelengths as great as predicted by the 'baseline' model of Stecker et al. can be ruled out with high confidence.

  10. The Basis of the Syllable Hierarchy: Articulatory Pressures or Universal Phonological Constraints?

    Science.gov (United States)

    Zhao, Xu; Berent, Iris

    2018-02-01

    Across languages, certain syllable types are systematically preferred to others (e.g., [Formula: see text] lbif, where [Formula: see text] indicates a preference). Previous research has shown that these preferences are active in the brains of individual speakers, they are evident even when none of these syllable types exists in participants' language, and even when the stimuli are presented in print. These results suggest that the syllable hierarchy cannot be reduced to either lexical or auditory/phonetic pressures. Here, we examine whether the syllable hierarchy is due to articulatory pressures. According to the motor embodiment view, the perception of a linguistic stimulus requires simulating its production; dispreferred syllables (e.g., lbif) are universally disliked because their production is harder to simulate. To address this possibility, we assessed syllable preferences while articulation was mechanically suppressed. Our four experiments each found significant effects of suppression. Remarkably, people remained sensitive to the syllable hierarchy regardless of suppression. Specifically, results with auditory materials (Experiments 1-2) showed strong effects of syllable structure irrespective of suppression. Moreover, syllable structure uniquely accounted for listeners' behavior even when controlling for several phonetic characteristics of our auditory materials. Results with printed stimuli (Experiments 3-4) were more complex, as participants in these experiments relied on both phonological and graphemic information. Nonetheless, readers were sensitive to most of the syllable hierarchy (e.g., [Formula: see text]), and these preferences emerged when articulation was suppressed, and even when the statistical properties of our materials were controlled via a regression analysis. Together, these findings indicate that speakers possess broad grammatical preferences that are irreducible to either sensory or motor factors.

  11. Mentoring: An Evolving Relationship.

    Science.gov (United States)

    Block, Michelle; Florczak, Kristine L

    2017-04-01

    The column concerns itself with mentoring as an evolving relationship between mentor and mentee. The collegiate mentoring model, the transformational transcendence model, and the humanbecoming mentoring model are considered in light of a dialogue with mentors at a Midwest university and conclusions are drawn.

  12. Teacher Trainers' and Trainees' Perceptions, Practices, and Constraints to Active Learning Methods: The Case of English Department in Bahir Dar University

    Science.gov (United States)

    Engidaw, Berhanu

    2014-01-01

    This study is on teacher trainers and teacher trainees' perceptions and practices of active learning and the constraints to implementing them in the English Department of Bahir Dar University. A mixed study approach that involves a quantitative self administered questionnaire, a semi-structured lesson observation guide, and qualitative in depth…

  13. Availability, Use and Constraints to Use of Electronic Information Resources by Postgraduates Students at the University of Ibadan

    Directory of Open Access Journals (Sweden)

    Dare Samuel Adeleke

    2017-12-01

    Full Text Available Availability, awareness and use of electronic resources provide access to authoritative, reliable, accurate and timely access to information. The use of electronic information resources (EIRs can enable innovation in teaching and increase timeliness in research of postgraduate students which will eventual result into encouragement of the expected research-led enquiry in this digital age. The study adopted a descriptive survey design. Samples of 300 of postgraduate students within seven out 13 Faculties were randomly selected. Data were collected using questionnaire designed to elicit response from respondents and data were analyzed using descriptive statistics methods percentages, mean, and standard deviation. Results indicated that internet was ranked most available and used in the university. Low level of usage of electronic resources, in particular, full texts data bases is linked to a number of constraints: Interrupted power supply was ranked highest among other factors as speed and capacity of computers, retrieval of records with high recall and low precision, retrieving records relevant to information need, lack of knowledge of search techniques to retrieve information effectively, non possession of requisite IT skills and problems accessing the internet. The study recommended that usage of electronic resources be made compulsory, intensifying awareness campaigns concerning the availability, training on use of electronic resources and the problem of power outage be addressed.

  14. Gone with the heat: a fundamental constraint on the imaging of dust and molecular gas in the early Universe.

    Science.gov (United States)

    Zhang, Zhi-Yu; Papadopoulos, Padelis P; Ivison, R J; Galametz, Maud; Smith, M W L; Xilouris, Emmanuel M

    2016-06-01

    Images of dust continuum and carbon monoxide (CO) line emission are powerful tools for deducing structural characteristics of galaxies, such as disc sizes, H2 gas velocity fields and enclosed H2 and dynamical masses. We report on a fundamental constraint set by the cosmic microwave background (CMB) on the observed structural and dynamical characteristics of galaxies, as deduced from dust continuum and CO-line imaging at high redshifts. As the CMB temperature rises in the distant Universe, the ensuing thermal equilibrium between the CMB and the cold dust and H2 gas progressively erases all spatial and spectral contrasts between their brightness distributions and the CMB. For high-redshift galaxies, this strongly biases the recoverable H2 gas and dust mass distributions, scale lengths, gas velocity fields and dynamical mass estimates. This limitation is unique to millimetre/submillimetre wavelengths and unlike its known effect on the global dust continuum and molecular line emission of galaxies, it cannot be addressed simply. We nevertheless identify a unique signature of CMB-affected continuum brightness distributions, namely an increasing rather than diminishing contrast between such brightness distributions and the CMB when the cold dust in distant galaxies is imaged at frequencies beyond the Raleigh-Jeans limit. For the molecular gas tracers, the same effect makes the atomic carbon lines maintain a larger contrast than the CO lines against the CMB.

  15. An integral constraint for the evolution of the galaxy two-point correlation function

    International Nuclear Information System (INIS)

    Peebles, P.J.E.; Groth, E.J.

    1976-01-01

    Under some conditions an integral over the galaxy two-point correlation function, xi(x,t), evolves with the expansion of the universe in a simple manner easily computed from linear perturbation theory.This provides a useful constraint on the possible evolution of xi(x,t) itself. We test the integral constraint with both an analytic model and numerical N-body simulations for the evolution of irregularities in an expanding universe. Some applications are discussed. (orig.) [de

  16. Maintaining evolvability.

    Science.gov (United States)

    Crow, James F

    2008-12-01

    Although molecular methods, such as QTL mapping, have revealed a number of loci with large effects, it is still likely that the bulk of quantitative variability is due to multiple factors, each with small effect. Typically, these have a large additive component. Conventional wisdom argues that selection, natural or artificial, uses up additive variance and thus depletes its supply. Over time, the variance should be reduced, and at equilibrium be near zero. This is especially expected for fitness and traits highly correlated with it. Yet, populations typically have a great deal of additive variance, and do not seem to run out of genetic variability even after many generations of directional selection. Long-term selection experiments show that populations continue to retain seemingly undiminished additive variance despite large changes in the mean value. I propose that there are several reasons for this. (i) The environment is continually changing so that what was formerly most fit no longer is. (ii) There is an input of genetic variance from mutation, and sometimes from migration. (iii) As intermediate-frequency alleles increase in frequency towards one, producing less variance (as p --> 1, p(1 - p) --> 0), others that were originally near zero become more common and increase the variance. Thus, a roughly constant variance is maintained. (iv) There is always selection for fitness and for characters closely related to it. To the extent that the trait is heritable, later generations inherit a disproportionate number of genes acting additively on the trait, thus increasing genetic variance. For these reasons a selected population retains its ability to evolve. Of course, genes with large effect are also important. Conspicuous examples are the small number of loci that changed teosinte to maize, and major phylogenetic changes in the animal kingdom. The relative importance of these along with duplications, chromosome rearrangements, horizontal transmission and polyploidy

  17. Allocating limited resources in a time of fiscal constraints: a priority setting case study from Dalhousie University Faculty of Medicine.

    Science.gov (United States)

    Mitton, Craig; Levy, Adrian; Gorsky, Diane; MacNeil, Christina; Dionne, Francois; Marrie, Tom

    2013-07-01

    Facing a projected $1.4M deficit on a $35M operating budget for fiscal year 2011/2012, members of the Dalhousie University Faculty of Medicine developed and implemented an explicit, transparent, criteria-based priority setting process for resource reallocation. A task group that included representatives from across the Faculty of Medicine used a program budgeting and marginal analysis (PBMA) framework, which provided an alternative to the typical public-sector approaches to addressing a budget deficit of across-the-board spending cuts and political negotiation. Key steps to the PBMA process included training staff members and department heads on priority setting and resource reallocation, establishing process guidelines to meet immediate and longer-term fiscal needs, developing a reporting structure and forming key working groups, creating assessment criteria to guide resource reallocation decisions, assessing disinvestment proposals from all departments, and providing proposal implementation recommendations to the dean. All departments were required to submit proposals for consideration. The task group approved 27 service reduction proposals and 28 efficiency gains proposals, totaling approximately $2.7M in savings across two years. During this process, the task group faced a number of challenges, including a tight timeline for development and implementation (January to April 2011), a culture that historically supported decentralized planning, at times competing interests (e.g., research versus teaching objectives), and reductions in overall health care and postsecondary education government funding. Overall, faculty and staff preferred the PBMA approach to previous practices. Other institutions should use this example to set priorities in times of fiscal constraints.

  18. Availability, Level of Use and Constraints to Use of Electronic Resources by Law Lecturers in Public Universities in Nigeria

    Science.gov (United States)

    Amusa, Oyintola Isiaka; Atinmo, Morayo

    2016-01-01

    (Purpose) This study surveyed the level of availability, use and constraints to use of electronic resources among law lecturers in Nigeria. (Methodology) Five hundred and fifty-two law lecturers were surveyed and four hundred and forty-two responded. (Results) Data analysis revealed that the level of availability of electronic resources for the…

  19. The "Iron Cage" of Division I Athletics and Football as Status Imperatives: Constraint and Change among American Universities

    Science.gov (United States)

    Fenex, Bart Lindy

    2010-01-01

    Throughout the history of American higher education sports have been closely identified with universities and campus life. Intercollegiate athletics occupies a peculiar space in the university; it is an institution within the universe of higher education. While extremely popular among many, there are charges that emphasis on college sports'…

  20. Rigorous theoretical constraint on constant negative EoS parameter [Formula: see text] and its effect for the late Universe.

    Science.gov (United States)

    Burgazli, Alvina; Eingorn, Maxim; Zhuk, Alexander

    In this paper, we consider the Universe at the late stage of its evolution and deep inside the cell of uniformity. At these scales, the Universe is filled with inhomogeneously distributed discrete structures (galaxies, groups and clusters of galaxies). Supposing that the Universe contains also the cosmological constant and a perfect fluid with a negative constant equation of state (EoS) parameter [Formula: see text] (e.g., quintessence, phantom or frustrated network of topological defects), we investigate scalar perturbations of the Friedmann-Robertson-Walker metrics due to inhomogeneities. Our analysis shows that, to be compatible with the theory of scalar perturbations, this perfect fluid, first, should be clustered and, second, should have the EoS parameter [Formula: see text]. In particular, this value corresponds to the frustrated network of cosmic strings. Therefore, the frustrated network of domain walls with [Formula: see text] is ruled out. A perfect fluid with [Formula: see text] neither accelerates nor decelerates the Universe. We also obtain the equation for the nonrelativistic gravitational potential created by a system of inhomogeneities. Due to the perfect fluid with [Formula: see text], the physically reasonable solutions take place for flat, open and closed Universes. This perfect fluid is concentrated around the inhomogeneities and results in screening of the gravitational potential.

  1. Constraint Differentiation

    DEFF Research Database (Denmark)

    Mödersheim, Sebastian Alexander; Basin, David; Viganò, Luca

    2010-01-01

    We introduce constraint differentiation, a powerful technique for reducing search when model-checking security protocols using constraint-based methods. Constraint differentiation works by eliminating certain kinds of redundancies that arise in the search space when using constraints to represent...... results show that constraint differentiation substantially reduces search and considerably improves the performance of OFMC, enabling its application to a wider class of problems....

  2. Evolvable synthetic neural system

    Science.gov (United States)

    Curtis, Steven A. (Inventor)

    2009-01-01

    An evolvable synthetic neural system includes an evolvable neural interface operably coupled to at least one neural basis function. Each neural basis function includes an evolvable neural interface operably coupled to a heuristic neural system to perform high-level functions and an autonomic neural system to perform low-level functions. In some embodiments, the evolvable synthetic neural system is operably coupled to one or more evolvable synthetic neural systems in a hierarchy.

  3. Constraints and changes in the development of science and technology policies in Argentina's University of Buenos Aires and the National Autonomous University of Mexico

    Science.gov (United States)

    Alcantara, Armando

    1999-06-01

    This dissertation is a comparison of the effects of structural adjustment on scientific and technological policies in two of the largest and most important universities of Latin America, UBA and UNAM. In its broadest sense, scientific and technological policies encompass a set of interventions, decisions, and activities of different institutions within a given society aimed to hinder or stimulate the progress of scientific research, and the application of its products to socioeconomic, political, cultural or military objectives. The methodological approach for this dissertation aimed to combine data collected at both the macro and micro levels. First, a profound examination of different bibliographical sources such as books, articles, and documents of different kinds (policy papers, national plans, and working papers), was carried out. Secondly, a series of interviews were conducted with scientists in some of the natural sciences' research centers and institutes, academic administrators and top officials of the S&T government agencies, in Argentina and Mexico, The main goal of these interviews was to understand the institutional dynamics as it was shaped by actors and processes, outside and within the two universities. This study found that the structural adjustment process in Argentina and Mexico has negatively affected the S&T policies in both UBA and UNAM. Local S&T played a original role in the two universities under scrutiny. Investments in science and technology have remained significantly low in Argentina and Mexico. In addition to this, the small amount of scientific personnel, the predominantly public characteristic of S&T funds, and the reduced number of doctoral graduates resulted in low levels of scientific output as compared with the number of publications in international scientific literature. A predominant academic orientation with few contributions to societal needs, either related to the productive sectors or to social problems such as pollution

  4. Quantifying the information in the long-range order of words: semantic structures and universal linguistic constraints.

    Science.gov (United States)

    Montemurro, Marcelo A

    2014-06-01

    We review some recent progress on the characterisation of long-range patterns of word use in language using methods from information theory. In particular, two levels of structure in language are considered. The first level corresponds to the patterns of words usage over different contextual domains. A direct application of information theory to quantify the specificity of words across different sections of a linguistic sequence leads to a measure of semantic information. Moreover, a natural scale emerges that characterises the typical size of semantic structures. Since the information measure is made up of additive contributions from individual words, it is possible to rank the words according to their overall weight in the total information. This allows the extraction of keywords most relevant to the semantic content of the sequence without any prior knowledge of the language. The second level considered is the complex structure of correlations among words in linguistic sequences. The degree of order in language can be quantified by means of the entropy. Reliable estimates of the entropy were obtained from corpora of texts from several linguistic families by means of lossless compression algorithms. The value of the entropy fluctuates across different languages since it depends on linguistic organisation at various levels. However, when a measure of relative entropy that specifically quantifies the degree of word ordering in language is estimated, it presents an almost constant value over all the linguistic families studied. This suggests that the entropy of word ordering is a novel quantitative linguistic universal. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Promoting universal financial protection: constraints and enabling factors in scaling-up coverage with social health insurance in Nigeria.

    Science.gov (United States)

    Onoka, Chima A; Onwujekwe, Obinna E; Uzochukwu, Benjamin S; Ezumah, Nkoli N

    2013-06-13

    The National Health Insurance Scheme (NHIS) in Nigeria was launched in 2005 as part of efforts by the federal government to achieve universal coverage using financial risk protection mechanisms. However, only 4% of the population, and mainly federal government employees, are currently covered by health insurance and this is primarily through the Formal Sector Social Health Insurance Programme (FSSHIP) of the NHIS. This study aimed to understand why different state (sub-national) governments decided whether or not to adopt the FSSHIP for their employees. This study used a comparative case study approach. Data were collected through document reviews and 48 in-depth interviews with policy makers, programme managers, health providers, and civil servant leaders. Although the programme's benefits seemed acceptable to state policy makers and the intended beneficiaries (employees), the feasibility of employer contributions, concerns about transparency in the NHIS and the role of states in the FSSHIP, the roles of policy champions such as state governors and resistance by employees to making contributions, all influenced the decision of state governments on adoption. Overall, the power of state governments over state-level health reforms, attributed to the prevailing system of government that allows states to deliberate on certain national-level policies, enhanced by the NHIS legislation that made adoption voluntary, enabled states to adopt or not to adopt the program. The study demonstrates and supports observations that even when the content of a programme is generally acceptable, context, actor roles, and the wider implications of programme design on actor interests can explain decision on policy adoption. Policy implementers involved in scaling-up the NHIS programme need to consider the prevailing contextual factors, and effectively engage policy champions to overcome known challenges in order to encourage adoption by sub-national governments. Policy makers and

  6. A Twenty-Year Look at “Computational Geology,” an Evolving, In-Discipline Course in Quantitative Literacy at the University of South Florida

    Directory of Open Access Journals (Sweden)

    Victor J. Ricchezza

    2017-01-01

    Full Text Available Since 1996, the Geology (GLY program at the USF has offered “Computational Geology” as part of its commitment to prepare undergraduate majors for the quantitative aspects of their field. The course focuses on geological-mathematical problem solving. Over its twenty years, the course has evolved from a GATC (geometry-algebra-trigonometry-calculus in-discipline capstone to a quantitative literacy (QL course taught within a natural science major. With the formation of the new School of Geosciences in 2013, the merging departments re-examined their various curricular programs. An online survey of the Geology Alumni Society found that “express quantitative evidence in support of an argument” was more favorably viewed as a workplace skill (4th out of 69 than algebra (51st, trig (55th and calculus 1 and 2 (59th and 60th. In that context, we decided to find out from successful alumni, “What did you get out of Computational Geology?” To that end, the first author carried out a formal, qualitative research study (narrative inquiry protocol, whereby he conducted, recorded, and transcribed semi-structured interviews of ten alumni selected from a list of 20 provided by the second author. In response to “Tell me what you remember from the course,” multiple alumni volunteered nine items: Excel (10 out of 10, Excel modules (8, Polya problem solving (5, “important” (4, unit conversions (4, back-of-the-envelope calculations (4, gender equality (3. In response to “Is there anything from the course that you used professionally or personally since graduating?” multiple alumni volunteered seven items: Excel (9 out of 10, QL/thinking (6, unit conversions (5, statistics (5, Excel modules (3, their notes (2. Outcome analysis from the open-ended comments arising from structured questions led to the identification of alumni takeaways in terms of elements of three values: (1 understanding and knowledge (facts such as conversion factors, and concepts

  7. Development and the evolvability of human limbs

    OpenAIRE

    Young, Nathan M.; Wagner, Günter P.; Hallgrímsson, Benedikt

    2010-01-01

    The long legs and short arms of humans are distinctive for a primate, the result of selection acting in opposite directions on each limb at different points in our evolutionary history. This mosaic pattern challenges our understanding of the relationship of development and evolvability because limbs are serially homologous and genetic correlations should act as a significant constraint on their independent evolution. Here we test a developmental model of limb covariation in anthropoid primate...

  8. Cosmographic Constraints and Cosmic Fluids

    Directory of Open Access Journals (Sweden)

    Salvatore Capozziello

    2013-12-01

    Full Text Available The problem of reproducing dark energy effects is reviewed here with particular interest devoted to cosmography. We summarize some of the most relevant cosmological models, based on the assumption that the corresponding barotropic equations of state evolve as the universe expands, giving rise to the accelerated expansion. We describe in detail the ΛCDM (Λ-Cold Dark Matter and ωCDM models, considering also some specific examples, e.g., Chevallier–Polarsky–Linder, the Chaplygin gas and the Dvali–Gabadadze–Porrati cosmological model. Finally, we consider the cosmological consequences of f(R and f(T gravities and their impact on the framework of cosmography. Keeping these considerations in mind, we point out the model-independent procedure related to cosmography, showing how to match the series of cosmological observables to the free parameters of each model. We critically discuss the role played by cosmography, as a selection criterion to check whether a particular model passes or does not present cosmological constraints. In so doing, we find out cosmological bounds by fitting the luminosity distance expansion of the redshift, z, adopting the recent Union 2.1 dataset of supernovae, combined with the baryonic acoustic oscillation and the cosmic microwave background measurements. We perform cosmographic analyses, imposing different priors on the Hubble rate present value. In addition, we compare our results with recent PLANCK limits, showing that the ΛCDM and ωCDM models seem to be the favorite with respect to other dark energy models. However, we show that cosmographic constraints on f(R and f(T cannot discriminate between extensions of General Relativity and dark energy models, leading to a disadvantageous degeneracy problem.

  9. Solar constraints

    International Nuclear Information System (INIS)

    Provost, J.

    1984-01-01

    Accurate tests of the theory of stellar structure and evolution are available from the Sun's observations. The solar constraints are reviewed, with a special attention to the recent progress in observing global solar oscillations. Each constraint is sensitive to a given region of the Sun. The present solar models (standard, low Z, mixed) are discussed with respect to neutrino flux, low and high degree five-minute oscillations and low degree internal gravity modes. It appears that actually there do not exist solar models able to fully account for all the observed quantities. (Auth.)

  10. The evolving Planck mass in classically scale-invariant theories

    Energy Technology Data Exchange (ETDEWEB)

    Kannike, K.; Raidal, M.; Spethmann, C.; Veermäe, H. [National Institute of Chemical Physics and Biophysics,Rävala 10, 10143 Tallinn (Estonia)

    2017-04-05

    We consider classically scale-invariant theories with non-minimally coupled scalar fields, where the Planck mass and the hierarchy of physical scales are dynamically generated. The classical theories possess a fixed point, where scale invariance is spontaneously broken. In these theories, however, the Planck mass becomes unstable in the presence of explicit sources of scale invariance breaking, such as non-relativistic matter and cosmological constant terms. We quantify the constraints on such classical models from Big Bang Nucleosynthesis that lead to an upper bound on the non-minimal coupling and require trans-Planckian field values. We show that quantum corrections to the scalar potential can stabilise the fixed point close to the minimum of the Coleman-Weinberg potential. The time-averaged motion of the evolving fixed point is strongly suppressed, thus the limits on the evolving gravitational constant from Big Bang Nucleosynthesis and other measurements do not presently constrain this class of theories. Field oscillations around the fixed point, if not damped, contribute to the dark matter density of the Universe.

  11. The evolving Planck mass in classically scale-invariant theories

    Science.gov (United States)

    Kannike, K.; Raidal, M.; Spethmann, C.; Veermäe, H.

    2017-04-01

    We consider classically scale-invariant theories with non-minimally coupled scalar fields, where the Planck mass and the hierarchy of physical scales are dynamically generated. The classical theories possess a fixed point, where scale invariance is spontaneously broken. In these theories, however, the Planck mass becomes unstable in the presence of explicit sources of scale invariance breaking, such as non-relativistic matter and cosmological constant terms. We quantify the constraints on such classical models from Big Bang Nucleosynthesis that lead to an upper bound on the non-minimal coupling and require trans-Planckian field values. We show that quantum corrections to the scalar potential can stabilise the fixed point close to the minimum of the Coleman-Weinberg potential. The time-averaged motion of the evolving fixed point is strongly suppressed, thus the limits on the evolving gravitational constant from Big Bang Nucleosynthesis and other measurements do not presently constrain this class of theories. Field oscillations around the fixed point, if not damped, contribute to the dark matter density of the Universe.

  12. Analyzing Evolving Social Network 2 (EVOLVE2)

    Science.gov (United States)

    2015-04-01

    WORK UNIT NUMBER N2 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) University of Southern California 3720 S. Flower Street, Third Floor Los...score, and resource allocation. Below the double line are link prediction heuristics introduced in this paper. name symbol definition common neighbors...LIST OF SYMBOLS , ABBREVIATIONS AND ACRONYMS A adjacency matrix of a network D diagonal out-degree matrix DW out-degree matrix of the reweighted network

  13. Methods Evolved by Observation

    Science.gov (United States)

    Montessori, Maria

    2016-01-01

    Montessori's idea of the child's nature and the teacher's perceptiveness begins with amazing simplicity, and when she speaks of "methods evolved," she is unveiling a methodological system for observation. She begins with the early childhood explosion into writing, which is a familiar child phenomenon that Montessori has written about…

  14. The constraints

    International Nuclear Information System (INIS)

    Jones, P.M.S.

    1987-01-01

    There are considerable incentives for the use of nuclear in preference to other sources for base load electricity generation in most of the developed world. These are economic, strategic, environmental and climatic. However, there are two potential constraints which could hinder the development of nuclear power to its full economic potential. These are public opinion and financial regulations which distort the nuclear economic advantage. The concerns of the anti-nuclear lobby are over safety, (especially following the Chernobyl accident), the management of radioactive waste, the potential effects of large scale exposure of the population to radiation and weapons proliferation. These are discussed. The financial constraint is over two factors, the availability of funds and the perception of cost, both of which are discussed. (U.K.)

  15. EVOLVE 2014 International Conference

    CERN Document Server

    Tantar, Emilia; Sun, Jian-Qiao; Zhang, Wei; Ding, Qian; Schütze, Oliver; Emmerich, Michael; Legrand, Pierrick; Moral, Pierre; Coello, Carlos

    2014-01-01

    This volume encloses research articles that were presented at the EVOLVE 2014 International Conference in Beijing, China, July 1–4, 2014.The book gathers contributions that emerged from the conference tracks, ranging from probability to set oriented numerics and evolutionary computation; all complemented by the bridging purpose of the conference, e.g. Complex Networks and Landscape Analysis, or by the more application oriented perspective. The novelty of the volume, when considering the EVOLVE series, comes from targeting also the practitioner’s view. This is supported by the Machine Learning Applied to Networks and Practical Aspects of Evolutionary Algorithms tracks, providing surveys on new application areas, as in the networking area and useful insights in the development of evolutionary techniques, from a practitioner’s perspective. Complementary to these directions, the conference tracks supporting the volume, follow on the individual advancements of the subareas constituting the scope of the confe...

  16. Evolving Procurement Organizations

    DEFF Research Database (Denmark)

    Bals, Lydia; Laine, Jari; Mugurusi, Godfrey

    Procurement has to find further levers and advance its contribution to corporate goals continuously. This places pressure on its organization in order to facilitate its performance. Therefore, procurement organizations constantly have to evolve in order to match these demands. A conceptual model...... and external contingency factors and having a more detailed look at the structural dimensions chosen, beyond the well-known characteristics of centralization, formalization, participation, specialization, standardization and size. From a theoretical perspective, it opens up insights that can be leveraged...

  17. Symbiotic Composition and Evolvability

    OpenAIRE

    Watson, Richard A.; Pollack, Jordan B.

    2001-01-01

    Several of the Major Transitions in natural evolution, such as the symbiogenic origin of eukaryotes from prokaryotes, share the feature that existing entities became the components of composite entities at a higher level of organisation. This composition of pre-adapted extant entities into a new whole is a fundamentally different source of variation from the gradual accumulation of small random variations, and it has some interesting consequences for issues of evolvability. In this paper we p...

  18. Evolvable Neural Software System

    Science.gov (United States)

    Curtis, Steven A.

    2009-01-01

    The Evolvable Neural Software System (ENSS) is composed of sets of Neural Basis Functions (NBFs), which can be totally autonomously created and removed according to the changing needs and requirements of the software system. The resulting structure is both hierarchical and self-similar in that a given set of NBFs may have a ruler NBF, which in turn communicates with other sets of NBFs. These sets of NBFs may function as nodes to a ruler node, which are also NBF constructs. In this manner, the synthetic neural system can exhibit the complexity, three-dimensional connectivity, and adaptability of biological neural systems. An added advantage of ENSS over a natural neural system is its ability to modify its core genetic code in response to environmental changes as reflected in needs and requirements. The neural system is fully adaptive and evolvable and is trainable before release. It continues to rewire itself while on the job. The NBF is a unique, bilevel intelligence neural system composed of a higher-level heuristic neural system (HNS) and a lower-level, autonomic neural system (ANS). Taken together, the HNS and the ANS give each NBF the complete capabilities of a biological neural system to match sensory inputs to actions. Another feature of the NBF is the Evolvable Neural Interface (ENI), which links the HNS and ANS. The ENI solves the interface problem between these two systems by actively adapting and evolving from a primitive initial state (a Neural Thread) to a complicated, operational ENI and successfully adapting to a training sequence of sensory input. This simulates the adaptation of a biological neural system in a developmental phase. Within the greater multi-NBF and multi-node ENSS, self-similar ENI s provide the basis for inter-NBF and inter-node connectivity.

  19. Evolved H II regions

    International Nuclear Information System (INIS)

    Churchwell, E.

    1975-01-01

    A probable evolutionary sequence of H II regions based on six distinct types of observed objects is suggested. Two examples which may deviate from this idealized sequence, are discussed. Even though a size-mean density relation of H II regions can be used as a rough indication of whether a nebula is very young or evolved, it is argued that such a relation is not likely to be useful for the quantitative assignment of ages to H II regions. Evolved H II regions appear to fit into one of four structural types: rings, core-halos, smooth structures, and irregular or filamentary structures. Examples of each type are given with their derived physical parameters. The energy balance in these nebulae is considered. The mass of ionized gas in evolved H II regions is in general too large to trace the nebula back to single compact H II regions. Finally, the morphological type of the Galaxy is considered from its H II region content. 2 tables, 2 figs., 29 refs

  20. EVOLVING AN EMPIRICAL METHODOLOGY DOR DETERMINING ...

    African Journals Online (AJOL)

    The uniqueness of this approach, is that it can be applied to any forest or dynamic feature on the earth, and can enjoy universal application as well. KEY WORDS: Evolving empirical methodology, innovative mathematical model, appropriate interval, remote sensing, forest environment planning and management. Global Jnl ...

  1. 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.

  2. Evolving production network structures

    DEFF Research Database (Denmark)

    Grunow, Martin; Gunther, H.O.; Burdenik, H.

    2007-01-01

    When deciding about future production network configurations, the current structures have to be taken into account. Further, core issues such as the maturity of the products and the capacity requirements for test runs and ramp-ups must be incorporated. Our approach is based on optimization...... modelling and assigns products and capacity expansions to production sites under the above constraints. It also considers the production complexity at the individual sites and the flexibility of the network. Our implementation results for a large manufacturing network reveal substantial possible cost...

  3. Development and the evolvability of human limbs.

    Science.gov (United States)

    Young, Nathan M; Wagner, Günter P; Hallgrímsson, Benedikt

    2010-02-23

    The long legs and short arms of humans are distinctive for a primate, the result of selection acting in opposite directions on each limb at different points in our evolutionary history. This mosaic pattern challenges our understanding of the relationship of development and evolvability because limbs are serially homologous and genetic correlations should act as a significant constraint on their independent evolution. Here we test a developmental model of limb covariation in anthropoid primates and demonstrate that both humans and apes exhibit significantly reduced integration between limbs when compared to quadrupedal monkeys. This result indicates that fossil hominins likely escaped constraints on independent limb variation via reductions to genetic pleiotropy in an ape-like last common ancestor (LCA). This critical change in integration among hominoids, which is reflected in macroevolutionary differences in the disparity between limb lengths, facilitated selection for modern human limb proportions and demonstrates how development helps shape evolutionary change.

  4. Evolving Procurement Organizations

    DEFF Research Database (Denmark)

    Bals, Lydia; Laiho, Aki; Laine, Jari

    Procurement has to find further levers and advance its contribution to corporate goals continuously. This places pressure on its organization in order to facilitate its performance. Therefore, Procurement organizations constantly have to evolve in order to match these demands. A conceptual model...... is presented and results of a first case study discussed. The findings highlight the importance of taking a contingency perspective on Procurement organization, understanding the internal and internal contingency factors. From a theoretical perspective, it opens up insights that can be furthermore leveraged...... in future studies in the fields of hybrid procurement organizations, global sourcing organizations as well as international procurement offices (IPOs). From a practical standpoint, an assessment of external and internal contingencies provides the opportunity to consciously match organization to its...

  5. Diffusion between evolving interfaces

    International Nuclear Information System (INIS)

    Juntunen, Janne; Merikoski, Juha

    2010-01-01

    Diffusion in an evolving environment is studied by continuous-time Monte Carlo simulations. Diffusion is modeled by continuous-time random walkers on a lattice, in a dynamic environment provided by bubbles between two one-dimensional interfaces driven symmetrically towards each other. For one-dimensional random walkers constrained by the interfaces, the bubble size distribution dominates diffusion. For two-dimensional random walkers, it is also controlled by the topography and dynamics of the interfaces. The results of the one-dimensional case are recovered in the limit where the interfaces are strongly driven. Even with simple hard-core repulsion between the interfaces and the particles, diffusion is found to depend strongly on the details of the dynamical rules of particles close to the interfaces.

  6. Why did heterospory evolve?

    Science.gov (United States)

    Petersen, Kurt B; Burd, Martin

    2017-08-01

    The primitive land plant life cycle featured the production of spores of unimodal size, a condition called homospory. The evolution of bimodal size distributions with small male spores and large female spores, known as heterospory, was an innovation that occurred repeatedly in the history of land plants. The importance of desiccation-resistant spores for colonization of the land is well known, but the adaptive value of heterospory has never been well established. It was an addition to a sexual life cycle that already involved male and female gametes. Its role as a precursor to the evolution of seeds has received much attention, but this is an evolutionary consequence of heterospory that cannot explain the transition from homospory to heterospory (and the lack of evolutionary reversal from heterospory to homospory). Enforced outcrossing of gametophytes has often been mentioned in connection to heterospory, but we review the shortcomings of this argument as an explanation of the selective advantage of heterospory. Few alternative arguments concerning the selective forces favouring heterospory have been proposed, a paucity of attention that is surprising given the importance of this innovation in land plant evolution. In this review we highlight two ideas that may lead us to a better understanding of why heterospory evolved. First, models of optimal resource allocation - an approach that has been used for decades in evolutionary ecology to help understand parental investment and other life-history patterns - suggest that an evolutionary increase in spore size could reach a threshold at which small spores yielding small, sperm-producing gametophytes would return greater fitness per unit of resource investment than would large spores and bisexual gametophytes. With the advent of such microspores, megaspores would evolve under frequency-dependent selection. This argument can account for the appearance of heterospory in the Devonian, when increasingly tall and complex

  7. Developmental constraints on behavioural flexibility.

    Science.gov (United States)

    Holekamp, Kay E; Swanson, Eli M; Van Meter, Page E

    2013-05-19

    We suggest that variation in mammalian behavioural flexibility not accounted for by current socioecological models may be explained in part by developmental constraints. From our own work, we provide examples of constraints affecting variation in behavioural flexibility, not only among individuals, but also among species and higher taxonomic units. We first implicate organizational maternal effects of androgens in shaping individual differences in aggressive behaviour emitted by female spotted hyaenas throughout the lifespan. We then compare carnivores and primates with respect to their locomotor and craniofacial adaptations. We inquire whether antagonistic selection pressures on the skull might impose differential functional constraints on evolvability of skulls and brains in these two orders, thus ultimately affecting behavioural flexibility in each group. We suggest that, even when carnivores and primates would theoretically benefit from the same adaptations with respect to behavioural flexibility, carnivores may nevertheless exhibit less behavioural flexibility than primates because of constraints imposed by past adaptations in the morphology of the limbs and skull. Phylogenetic analysis consistent with this idea suggests greater evolutionary lability in relative brain size within families of primates than carnivores. Thus, consideration of developmental constraints may help elucidate variation in mammalian behavioural flexibility.

  8. Evolving a photosynthetic organelle

    Directory of Open Access Journals (Sweden)

    Nakayama Takuro

    2012-04-01

    Full Text Available Abstract The evolution of plastids from cyanobacteria is believed to represent a singularity in the history of life. The enigmatic amoeba Paulinella and its 'recently' acquired photosynthetic inclusions provide a fascinating system through which to gain fresh insight into how endosymbionts become organelles. The plastids, or chloroplasts, of algae and plants evolved from cyanobacteria by endosymbiosis. This landmark event conferred on eukaryotes the benefits of photosynthesis - the conversion of solar energy into chemical energy - and in so doing had a huge impact on the course of evolution and the climate of Earth 1. From the present state of plastids, however, it is difficult to trace the evolutionary steps involved in this momentous development, because all modern-day plastids have fully integrated into their hosts. Paulinella chromatophora is a unicellular eukaryote that bears photosynthetic entities called chromatophores that are derived from cyanobacteria and has thus received much attention as a possible example of an organism in the early stages of organellogenesis. Recent studies have unlocked the genomic secrets of its chromatophore 23 and provided concrete evidence that the Paulinella chromatophore is a bona fide photosynthetic organelle 4. The question is how Paulinella can help us to understand the process by which an endosymbiont is converted into an organelle.

  9. Fat: an evolving issue

    Directory of Open Access Journals (Sweden)

    John R. Speakman

    2012-09-01

    Work on obesity is evolving, and obesity is a consequence of our evolutionary history. In the space of 50 years, we have become an obese species. The reasons why can be addressed at a number of different levels. These include separating between whether the primary cause lies on the food intake or energy expenditure side of the energy balance equation, and determining how genetic and environmental effects contribute to weight variation between individuals. Opinion on whether increased food intake or decreased energy expenditure drives the obesity epidemic is still divided, but recent evidence favours the idea that food intake, rather than altered expenditure, is most important. There is more of a consensus that genetics explains most (probably around 65% of weight variation between individuals. Recent advances in genome-wide association studies have identified many polymorphisms that are linked to obesity, yet much of the genetic variance remains unexplained. Finding the causes of this unexplained variation will be an impetus of genetic and epigenetic research on obesity over the next decade. Many environmental factors – including gut microbiota, stress and endocrine disruptors – have been linked to the risk of developing obesity. A better understanding of gene-by-environment interactions will also be key to understanding obesity in the years to come.

  10. Evolving a photosynthetic organelle.

    Science.gov (United States)

    Nakayama, Takuro; Archibald, John M

    2012-04-24

    The evolution of plastids from cyanobacteria is believed to represent a singularity in the history of life. The enigmatic amoeba Paulinella and its 'recently' acquired photosynthetic inclusions provide a fascinating system through which to gain fresh insight into how endosymbionts become organelles.The plastids, or chloroplasts, of algae and plants evolved from cyanobacteria by endosymbiosis. This landmark event conferred on eukaryotes the benefits of photosynthesis--the conversion of solar energy into chemical energy--and in so doing had a huge impact on the course of evolution and the climate of Earth 1. From the present state of plastids, however, it is difficult to trace the evolutionary steps involved in this momentous development, because all modern-day plastids have fully integrated into their hosts. Paulinella chromatophora is a unicellular eukaryote that bears photosynthetic entities called chromatophores that are derived from cyanobacteria and has thus received much attention as a possible example of an organism in the early stages of organellogenesis. Recent studies have unlocked the genomic secrets of its chromatophore 23 and provided concrete evidence that the Paulinella chromatophore is a bona fide photosynthetic organelle 4. The question is how Paulinella can help us to understand the process by which an endosymbiont is converted into an organelle.

  11. Communicability across evolving networks.

    Science.gov (United States)

    Grindrod, Peter; Parsons, Mark C; Higham, Desmond J; Estrada, Ernesto

    2011-04-01

    Many natural and technological applications generate time-ordered sequences of networks, defined over a fixed set of nodes; for example, time-stamped information about "who phoned who" or "who came into contact with who" arise naturally in studies of communication and the spread of disease. Concepts and algorithms for static networks do not immediately carry through to this dynamic setting. For example, suppose A and B interact in the morning, and then B and C interact in the afternoon. Information, or disease, may then pass from A to C, but not vice versa. This subtlety is lost if we simply summarize using the daily aggregate network given by the chain A-B-C. However, using a natural definition of a walk on an evolving network, we show that classic centrality measures from the static setting can be extended in a computationally convenient manner. In particular, communicability indices can be computed to summarize the ability of each node to broadcast and receive information. The computations involve basic operations in linear algebra, and the asymmetry caused by time's arrow is captured naturally through the noncommutativity of matrix-matrix multiplication. Illustrative examples are given for both synthetic and real-world communication data sets. We also discuss the use of the new centrality measures for real-time monitoring and prediction.

  12. Evolving Concepts of Asthma

    Science.gov (United States)

    Ray, Anuradha; Wenzel, Sally E.

    2015-01-01

    Our understanding of asthma has evolved over time from a singular disease to a complex of various phenotypes, with varied natural histories, physiologies, and responses to treatment. Early therapies treated most patients with asthma similarly, with bronchodilators and corticosteroids, but these therapies had varying degrees of success. Similarly, despite initial studies that identified an underlying type 2 inflammation in the airways of patients with asthma, biologic therapies targeted toward these type 2 pathways were unsuccessful in all patients. These observations led to increased interest in phenotyping asthma. Clinical approaches, both biased and later unbiased/statistical approaches to large asthma patient cohorts, identified a variety of patient characteristics, but they also consistently identified the importance of age of onset of disease and the presence of eosinophils in determining clinically relevant phenotypes. These paralleled molecular approaches to phenotyping that developed an understanding that not all patients share a type 2 inflammatory pattern. Using biomarkers to select patients with type 2 inflammation, repeated trials of biologics directed toward type 2 cytokine pathways saw newfound success, confirming the importance of phenotyping in asthma. Further research is needed to clarify additional clinical and molecular phenotypes, validate predictive biomarkers, and identify new areas for possible interventions. PMID:26161792

  13. UKAEA'S evolving contract philosophy

    International Nuclear Information System (INIS)

    Nicol, R. D.

    2003-01-01

    The United Kingdom Atomic Energy Authority (UKAEA) has gone through fundamental change over the last ten years. At the heart of this change has been UKAEA's relationship with the contracting and supply market. This paper describes the way in which UKAEA actively developed the market to support the decommissioning programme, and how the approach to contracting has evolved as external pressures and demands have changed. UKAEA's pro-active approach to industry has greatly assisted the development of a healthy, competitive market for services supporting decommissioning in the UK. There have been difficult changes and many challenges along the way, and some retrenchment was necessary to meet regulatory requirements. Nevertheless, UKAEA has sustained a high level of competition - now measured in terms of competed spend as a proportion of competable spend - with annual out-turns consistently over 80%. The prime responsibility for market development will pass to the new Nuclear Decommissioning Authority (NDA) in 2005, as the owner, on behalf of the Government, of the UK's civil nuclear liabilities. The preparatory work for the NDA indicates that the principles established by UKAEA will be carried forward. (author)

  14. The Evolving Leadership Path of Visual Analytics

    Energy Technology Data Exchange (ETDEWEB)

    Kluse, Michael; Peurrung, Anthony J.; Gracio, Deborah K.

    2012-01-02

    This is a requested book chapter for an internationally authored book on visual analytics and related fields, coordianted by a UK university and to be published by Springer in 2012. This chapter is an overview of the leadship strategies that PNNL's Jim Thomas and other stakeholders used to establish visual analytics as a field, and how those strategies may evolve in the future.

  15. CMIP6 Data Citation of Evolving Data

    Directory of Open Access Journals (Sweden)

    Martina Stockhause

    2017-06-01

    Full Text Available Data citations have become widely accepted. Technical infrastructures as well as principles and recommendations for data citation are in place but best practices or guidelines for their implementation are not yet available. On the other hand, the scientific climate community requests early citations on evolving data for credit, e.g. for CMIP6 (Coupled Model Intercomparison Project Phase 6. The data citation concept for CMIP6 is presented. The main challenges lie in limited resources, a strict project timeline and the dependency on changes of the data dissemination infrastructure ESGF (Earth System Grid Federation to meet the data citation requirements. Therefore a pragmatic, flexible and extendible approach for the CMIP6 data citation service was developed, consisting of a citation for the full evolving data superset and a data cart approach for citing the concrete used data subset. This two citation approach can be implemented according to the RDA recommendations for evolving data. Because of resource constraints and missing project policies, the implementation of the second part of the citation concept is postponed to CMIP7.

  16. Toward making the constraint hypersurface an attractor in free evolution

    International Nuclear Information System (INIS)

    Fiske, David R.

    2004-01-01

    When constructing numerical solutions to systems of evolution equations subject to a constraint, one must decide what role the constraint equations will play in the evolution system. In one popular choice, known as free evolution, a simulation is treated as a Cauchy problem, with the initial data constructed to satisfy the constraint equations. This initial data are then evolved via the evolution equations with no further enforcement of the constraint equations. The evolution, however, via the discretized evolution equations introduce constraint violating modes at the level of truncation error, and these constraint violating modes will behave in a formalism dependent way. This paper presents a generic method for incorporating the constraint equations into the evolution equations so that the off-constraint dynamics are biased toward the constraint satisfying solutions

  17. Constraints on the nature of inertial motion arising from the universality of free fall and the conformal causal structure of space-time

    International Nuclear Information System (INIS)

    Coleman, R.A.; Korte, H.

    1984-01-01

    According to the principle of the universality of free fall, the motions of all neutral monopole particles are governed by one common path structure. This principle does not, however, require the path structure to be geodesic; that is, the path structure need not be a projective structure. It is shown that any equation of motion structure (either a curve or a path structure) that has sufficient microisotropy to be compatible with the conformal causal structure of space-time must be geodesic and must be unique. Hence, the empirically well-supported principles of conformal causality and of the universality of free fall together require the existence of a unique Weyl structure on space-time

  18. Economies Evolve by Energy Dispersal

    Directory of Open Access Journals (Sweden)

    Stanley Salthe

    2009-10-01

    Full Text Available Economic activity can be regarded as an evolutionary process governed by the 2nd law of thermodynamics. The universal law, when formulated locally as an equation of motion, reveals that a growing economy develops functional machinery and organizes hierarchically in such a way as to tend to equalize energy density differences within the economy and in respect to the surroundings it is open to. Diverse economic activities result in flows of energy that will preferentially channel along the most steeply descending paths, leveling a non-Euclidean free energy landscape. This principle of 'maximal energy dispersal‘, equivalent to the maximal rate of entropy production, gives rise to economic laws and regularities. The law of diminishing returns follows from the diminishing free energy while the relation between supply and demand displays a quest for a balance among interdependent energy densities. Economic evolution is dissipative motion where the driving forces and energy flows are inseparable from each other. When there are multiple degrees of freedom, economic growth and decline are inherently impossible to forecast in detail. Namely, trajectories of an evolving economy are non-integrable, i.e. unpredictable in detail because a decision by a player will affect also future decisions of other players. We propose that decision making is ultimately about choosing from various actions those that would reduce most effectively subjectively perceived energy gradients.

  19. Solar system constraints on disformal gravity theories

    International Nuclear Information System (INIS)

    Ip, Hiu Yan; Schmidt, Fabian; Sakstein, Jeremy

    2015-01-01

    Disformal theories of gravity are scalar-tensor theories where the scalar couples derivatively to matter via the Jordan frame metric. These models have recently attracted interest in the cosmological context since they admit accelerating solutions. We derive the solution for a static isolated mass in generic disformal gravity theories and transform it into the parameterised post-Newtonian form. This allows us to investigate constraints placed on such theories by local tests of gravity. The tightest constraints come from preferred-frame effects due to the motion of the Solar System with respect to the evolving cosmological background field. The constraints we obtain improve upon the previous solar system constraints by two orders of magnitude, and constrain the scale of the disformal coupling for generic models to ℳ ∼> 100 eV. These constraints render all disformal effects irrelevant for cosmology

  20. Relativistic numerical cosmology with silent universes

    Science.gov (United States)

    Bolejko, Krzysztof

    2018-01-01

    Relativistic numerical cosmology is most often based either on the exact solutions of the Einstein equations, or perturbation theory, or weak-field limit, or the BSSN formalism. The silent universe provides an alternative approach to investigate relativistic evolution of cosmological systems. The silent universe is based on the solution of the Einstein equations in 1  +  3 comoving coordinates with additional constraints imposed. These constraints include: the gravitational field is sourced by dust and cosmological constant only, both rotation and magnetic part of the Weyl tensor vanish, and the shear is diagnosable. This paper describes the code simsilun (free software distributed under the terms of the reposi General Public License), which implements the equations of the silent universe. The paper also discusses applications of the silent universe and it uses the Millennium simulation to set up the initial conditions for the code simsilun. The simulation obtained this way consists of 16 777 216 worldlines, which are evolved from z  =  80 to z  =  0. Initially, the mean evolution (averaged over the whole domain) follows the evolution of the background ΛCDM model. However, once the evolution of cosmic structures becomes nonlinear, the spatial curvature evolves from ΩK =0 to ΩK ≈ 0.1 at the present day. The emergence of the spatial curvature is associated with ΩM and Ω_Λ being smaller by approximately 0.05 compared to the ΛCDM.

  1. Evolving expectations from international organisations

    International Nuclear Information System (INIS)

    Ruiz Lopez, C.

    2008-01-01

    The author stated that implementation of the geological disposal concept requires a strategy that provides national decision makers with sufficient confidence in the level of long-term safety and protection ultimately achieved. The concept of protection against harm has a broader meaning than radiological protection in terms of risk and dose. It includes the protection of the environment and socio-economic interests of communities. She recognised that a number of countries have established regulatory criteria already, and others are now discussing what constitutes a proper regulatory test and suitable time frame for judging the safety of long-term disposal. Each regulatory programme seeks to define reasonable tests of repository performance, using protection criteria and safety approaches consistent with the culture, values and expectations of the citizens of the country concerned. This means that there are differences in how protection and safety are addressed in national approaches to regulation and in the bases used for that. However, as was recognised in the Cordoba Workshop, it would be important to reach a minimum level of consistency and be able to explain the differences. C. Ruiz-Lopez presented an overview of the development of international guidance from ICRP, IAEA and NEA from the Cordoba workshop up to now, and positions of independent National Advisory Bodies. The evolution of these guidelines over time demonstrates an evolving understanding of long-term implications, with the recognition that dose and risk constraints should not be seen as measures of detriment beyond a few hundred years, the emphasis on sound engineering practices, and the introduction of new concepts and approaches which take into account social and economical aspects (e.g. constrained optimisation, BAT, managerial principles). In its new recommendations, ICRP (draft 2006) recognizes. in particular, that decision making processes may depend on other societal concerns and considers

  2. Disgust: Evolved function and structure

    NARCIS (Netherlands)

    Tybur, J.M.; Lieberman, D.; Kurzban, R.; DeScioli, P.

    2013-01-01

    Interest in and research on disgust has surged over the past few decades. The field, however, still lacks a coherent theoretical framework for understanding the evolved function or functions of disgust. Here we present such a framework, emphasizing 2 levels of analysis: that of evolved function and

  3. Natural selection promotes antigenic evolvability

    NARCIS (Netherlands)

    Graves, C.J.; Ros, V.I.D.; Stevenson, B.; Sniegowski, P.D.; Brisson, D.

    2013-01-01

    The hypothesis that evolvability - the capacity to evolve by natural selection - is itself the object of natural selection is highly intriguing but remains controversial due in large part to a paucity of direct experimental evidence. The antigenic variation mechanisms of microbial pathogens provide

  4. Dynamics and constraints of the Dissipative Liouville Cosmology

    CERN Document Server

    Basilakos, Spyros; Mitsou, Vasiliki A; Plionis, Manolis

    2012-01-01

    In this article we investigate the properties of the FLRW flat cosmological models in which the cosmic expansion of the Universe is affected by a dilaton dark energy (Liouville scenario). In particular, we perform a detailed study of these models in the light of the latest cosmological data, which serves to illustrate the phenomenological viability of the new dark energy paradigm as a serious alternative to the traditional scalar field approaches. By performing a joint likelihood analysis of the recent supernovae type Ia data (SNIa), the differential ages of passively evolving galaxies, and the Baryonic Acoustic Oscillations (BAOs) traced by the Sloan Digital Sky Survey (SDSS), we put tight constraints on the main cosmological parameters. Furthermore, we study the linear matter fluctuation field of the above Liouville cosmological models. In this framework, we compare the observed growth rate of clustering measured from the optical galaxies with those predicted by the current Liouville models. Performing vari...

  5. Evolvability Is an Evolved Ability: The Coding Concept as the Arch-Unit of Natural Selection.

    Science.gov (United States)

    Janković, Srdja; Ćirković, Milan M

    2016-03-01

    Physical processes that characterize living matter are qualitatively distinct in that they involve encoding and transfer of specific types of information. Such information plays an active part in the control of events that are ultimately linked to the capacity of the system to persist and multiply. This algorithmicity of life is a key prerequisite for its Darwinian evolution, driven by natural selection acting upon stochastically arising variations of the encoded information. The concept of evolvability attempts to define the total capacity of a system to evolve new encoded traits under appropriate conditions, i.e., the accessible section of total morphological space. Since this is dependent on previously evolved regulatory networks that govern information flow in the system, evolvability itself may be regarded as an evolved ability. The way information is physically written, read and modified in living cells (the "coding concept") has not changed substantially during the whole history of the Earth's biosphere. This biosphere, be it alone or one of many, is, accordingly, itself a product of natural selection, since the overall evolvability conferred by its coding concept (nucleic acids as information carriers with the "rulebook of meanings" provided by codons, as well as all the subsystems that regulate various conditional information-reading modes) certainly played a key role in enabling this biosphere to survive up to the present, through alterations of planetary conditions, including at least five catastrophic events linked to major mass extinctions. We submit that, whatever the actual prebiotic physical and chemical processes may have been on our home planet, or may, in principle, occur at some time and place in the Universe, a particular coding concept, with its respective potential to give rise to a biosphere, or class of biospheres, of a certain evolvability, may itself be regarded as a unit (indeed the arch-unit) of natural selection.

  6. Dark matter constraints in the minimal and nonminimal supersymmetric standard model

    International Nuclear Information System (INIS)

    Stephan, A.

    1998-01-01

    We determine the allowed parameter space and the particle spectra of the minimal SUSY standard model (MSSM) and nonminimal SUSY standard model (NMSSM) imposing correct electroweak gauge symmetry breaking and recent experimental constraints. The parameters of the models are evolved with the SUSY renormalization group equations assuming universality at the grand unified scale. Applying the new unbounded from below constraints we can exclude the lightest SUSY particle singlinos and light scalar and pseudoscalar Higgs singlets of the NMSSM. This exclusion removes the experimental possibility to distinguish between the MSSM and NMSSM via the recently proposed search for an additional cascade produced in the decay of the B-ino into the LSP singlino. Furthermore, the effects of the dark matter condition for the MSSM and NMSSM are investigated and the differences concerning the parameter space, the SUSY particle, and Higgs sector are discussed. thinsp copyright 1998 The American Physical Society

  7. Spacetimes containing slowly evolving horizons

    International Nuclear Information System (INIS)

    Kavanagh, William; Booth, Ivan

    2006-01-01

    Slowly evolving horizons are trapping horizons that are ''almost'' isolated horizons. This paper reviews their definition and discusses several spacetimes containing such structures. These include certain Vaidya and Tolman-Bondi solutions as well as (perturbatively) tidally distorted black holes. Taking into account the mass scales and orders of magnitude that arise in these calculations, we conjecture that slowly evolving horizons are the norm rather than the exception in astrophysical processes that involve stellar-scale black holes

  8. Natural selection promotes antigenic evolvability.

    Science.gov (United States)

    Graves, Christopher J; Ros, Vera I D; Stevenson, Brian; Sniegowski, Paul D; Brisson, Dustin

    2013-01-01

    The hypothesis that evolvability - the capacity to evolve by natural selection - is itself the object of natural selection is highly intriguing but remains controversial due in large part to a paucity of direct experimental evidence. The antigenic variation mechanisms of microbial pathogens provide an experimentally tractable system to test whether natural selection has favored mechanisms that increase evolvability. Many antigenic variation systems consist of paralogous unexpressed 'cassettes' that recombine into an expression site to rapidly alter the expressed protein. Importantly, the magnitude of antigenic change is a function of the genetic diversity among the unexpressed cassettes. Thus, evidence that selection favors among-cassette diversity is direct evidence that natural selection promotes antigenic evolvability. We used the Lyme disease bacterium, Borrelia burgdorferi, as a model to test the prediction that natural selection favors amino acid diversity among unexpressed vls cassettes and thereby promotes evolvability in a primary surface antigen, VlsE. The hypothesis that diversity among vls cassettes is favored by natural selection was supported in each B. burgdorferi strain analyzed using both classical (dN/dS ratios) and Bayesian population genetic analyses of genetic sequence data. This hypothesis was also supported by the conservation of highly mutable tandem-repeat structures across B. burgdorferi strains despite a near complete absence of sequence conservation. Diversification among vls cassettes due to natural selection and mutable repeat structures promotes long-term antigenic evolvability of VlsE. These findings provide a direct demonstration that molecular mechanisms that enhance evolvability of surface antigens are an evolutionary adaptation. The molecular evolutionary processes identified here can serve as a model for the evolution of antigenic evolvability in many pathogens which utilize similar strategies to establish chronic infections.

  9. Natural selection promotes antigenic evolvability.

    Directory of Open Access Journals (Sweden)

    Christopher J Graves

    Full Text Available The hypothesis that evolvability - the capacity to evolve by natural selection - is itself the object of natural selection is highly intriguing but remains controversial due in large part to a paucity of direct experimental evidence. The antigenic variation mechanisms of microbial pathogens provide an experimentally tractable system to test whether natural selection has favored mechanisms that increase evolvability. Many antigenic variation systems consist of paralogous unexpressed 'cassettes' that recombine into an expression site to rapidly alter the expressed protein. Importantly, the magnitude of antigenic change is a function of the genetic diversity among the unexpressed cassettes. Thus, evidence that selection favors among-cassette diversity is direct evidence that natural selection promotes antigenic evolvability. We used the Lyme disease bacterium, Borrelia burgdorferi, as a model to test the prediction that natural selection favors amino acid diversity among unexpressed vls cassettes and thereby promotes evolvability in a primary surface antigen, VlsE. The hypothesis that diversity among vls cassettes is favored by natural selection was supported in each B. burgdorferi strain analyzed using both classical (dN/dS ratios and Bayesian population genetic analyses of genetic sequence data. This hypothesis was also supported by the conservation of highly mutable tandem-repeat structures across B. burgdorferi strains despite a near complete absence of sequence conservation. Diversification among vls cassettes due to natural selection and mutable repeat structures promotes long-term antigenic evolvability of VlsE. These findings provide a direct demonstration that molecular mechanisms that enhance evolvability of surface antigens are an evolutionary adaptation. The molecular evolutionary processes identified here can serve as a model for the evolution of antigenic evolvability in many pathogens which utilize similar strategies to establish

  10. Macroscopic constraints on string unification

    International Nuclear Information System (INIS)

    Taylor, T.R.

    1989-03-01

    The comparison of sting theory with experiment requires a huge extrapolation from the microscopic distances, of order of the Planck length, up to the macroscopic laboratory distances. The quantum effects give rise to large corrections to the macroscopic predictions of sting unification. I discus the model-independent constraints on the gravitational sector of string theory due to the inevitable existence of universal Fradkin-Tseytlin dilatons. 9 refs

  11. Robustness to Faults Promotes Evolvability: Insights from Evolving Digital Circuits.

    Science.gov (United States)

    Milano, Nicola; Nolfi, Stefano

    2016-01-01

    We demonstrate how the need to cope with operational faults enables evolving circuits to find more fit solutions. The analysis of the results obtained in different experimental conditions indicates that, in absence of faults, evolution tends to select circuits that are small and have low phenotypic variability and evolvability. The need to face operation faults, instead, drives evolution toward the selection of larger circuits that are truly robust with respect to genetic variations and that have a greater level of phenotypic variability and evolvability. Overall our results indicate that the need to cope with operation faults leads to the selection of circuits that have a greater probability to generate better circuits as a result of genetic variation with respect to a control condition in which circuits are not subjected to faults.

  12. A neighbourhood evolving network model

    International Nuclear Information System (INIS)

    Cao, Y.J.; Wang, G.Z.; Jiang, Q.Y.; Han, Z.X.

    2006-01-01

    Many social, technological, biological and economical systems are best described by evolved network models. In this short Letter, we propose and study a new evolving network model. The model is based on the new concept of neighbourhood connectivity, which exists in many physical complex networks. The statistical properties and dynamics of the proposed model is analytically studied and compared with those of Barabasi-Albert scale-free model. Numerical simulations indicate that this network model yields a transition between power-law and exponential scaling, while the Barabasi-Albert scale-free model is only one of its special (limiting) cases. Particularly, this model can be used to enhance the evolving mechanism of complex networks in the real world, such as some social networks development

  13. Evolvable Mars Campaign Long Duration Habitation Strategies: Architectural Approaches to Enable Human Exploration Missions

    Science.gov (United States)

    Simon, Matthew A.; Toups, Larry; Howe, A. Scott; Wald, Samuel I.

    2015-01-01

    The Evolvable Mars Campaign (EMC) is the current NASA Mars mission planning effort which seeks to establish sustainable, realistic strategies to enable crewed Mars missions in the mid-2030s timeframe. The primary outcome of the Evolvable Mars Campaign is not to produce "The Plan" for sending humans to Mars, but instead its intent is to inform the Human Exploration and Operations Mission Directorate near-term key decisions and investment priorities to prepare for those types of missions. The FY'15 EMC effort focused upon analysis of integrated mission architectures to identify technically appealing transportation strategies, logistics build-up strategies, and vehicle designs for reaching and exploring Mars moons and Mars surface. As part of the development of this campaign, long duration habitats are required which are capable of supporting crew with limited resupply and crew abort during the Mars transit, Mars moons, and Mars surface segments of EMC missions. In particular, the EMC design team sought to design a single, affordable habitation system whose manufactured units could be outfitted uniquely for each of these missions and reused for multiple crewed missions. This habitat system must provide all of the functionality to safely support 4 crew for long durations while meeting mass and volume constraints for each of the mission segments set by the chosen transportation architecture and propulsion technologies. This paper describes several proposed long-duration habitation strategies to enable the Evolvable Mars Campaign through improvements in mass, cost, and reusability, and presents results of analysis to compare the options and identify promising solutions. The concepts investigated include several monolithic concepts: monolithic clean sheet designs, and concepts which leverage the co-manifested payload capability of NASA's Space Launch System (SLS) to deliver habitable elements within the Universal Payload Adaptor between the SLS upper stage and the Orion

  14. Evolving phenotypic networks in silico.

    Science.gov (United States)

    François, Paul

    2014-11-01

    Evolved gene networks are constrained by natural selection. Their structures and functions are consequently far from being random, as exemplified by the multiple instances of parallel/convergent evolution. One can thus ask if features of actual gene networks can be recovered from evolutionary first principles. I review a method for in silico evolution of small models of gene networks aiming at performing predefined biological functions. I summarize the current implementation of the algorithm, insisting on the construction of a proper "fitness" function. I illustrate the approach on three examples: biochemical adaptation, ligand discrimination and vertebrate segmentation (somitogenesis). While the structure of the evolved networks is variable, dynamics of our evolved networks are usually constrained and present many similar features to actual gene networks, including properties that were not explicitly selected for. In silico evolution can thus be used to predict biological behaviours without a detailed knowledge of the mapping between genotype and phenotype. Copyright © 2014 The Author. Published by Elsevier Ltd.. All rights reserved.

  15. Ranking in evolving complex networks

    Science.gov (United States)

    Liao, Hao; Mariani, Manuel Sebastian; Medo, Matúš; Zhang, Yi-Cheng; Zhou, Ming-Yang

    2017-05-01

    Complex networks have emerged as a simple yet powerful framework to represent and analyze a wide range of complex systems. The problem of ranking the nodes and the edges in complex networks is critical for a broad range of real-world problems because it affects how we access online information and products, how success and talent are evaluated in human activities, and how scarce resources are allocated by companies and policymakers, among others. This calls for a deep understanding of how existing ranking algorithms perform, and which are their possible biases that may impair their effectiveness. Many popular ranking algorithms (such as Google's PageRank) are static in nature and, as a consequence, they exhibit important shortcomings when applied to real networks that rapidly evolve in time. At the same time, recent advances in the understanding and modeling of evolving networks have enabled the development of a wide and diverse range of ranking algorithms that take the temporal dimension into account. The aim of this review is to survey the existing ranking algorithms, both static and time-aware, and their applications to evolving networks. We emphasize both the impact of network evolution on well-established static algorithms and the benefits from including the temporal dimension for tasks such as prediction of network traffic, prediction of future links, and identification of significant nodes.

  16. Financing Constraints and Entrepreneurship

    OpenAIRE

    William R. Kerr; Ramana Nanda

    2009-01-01

    Financing constraints are one of the biggest concerns impacting potential entrepreneurs around the world. Given the important role that entrepreneurship is believed to play in the process of economic growth, alleviating financing constraints for would-be entrepreneurs is also an important goal for policymakers worldwide. We review two major streams of research examining the relevance of financing constraints for entrepreneurship. We then introduce a framework that provides a unified perspecti...

  17. Temporal Concurrent Constraint Programming

    DEFF Research Database (Denmark)

    Nielsen, Mogens; Valencia Posso, Frank Dan

    2002-01-01

    The ntcc calculus is a model of non-deterministic temporal concurrent constraint programming. In this paper we study behavioral notions for this calculus. In the underlying computational model, concurrent constraint processes are executed in discrete time intervals. The behavioral notions studied...... reflect the reactive interactions between concurrent constraint processes and their environment, as well as internal interactions between individual processes. Relationships between the suggested notions are studied, and they are all proved to be decidable for a substantial fragment of the calculus...

  18. Functional Topology of Evolving Urban Drainage Networks

    Science.gov (United States)

    Yang, Soohyun; Paik, Kyungrock; McGrath, Gavan S.; Urich, Christian; Krueger, Elisabeth; Kumar, Praveen; Rao, P. Suresh C.

    2017-11-01

    We investigated the scaling and topology of engineered urban drainage networks (UDNs) in two cities, and further examined UDN evolution over decades. UDN scaling was analyzed using two power law scaling characteristics widely employed for river networks: (1) Hack's law of length (L)-area (A) [L∝Ah] and (2) exceedance probability distribution of upstream contributing area (δ) [P>(A≥δ>)˜aδ-ɛ]. For the smallest UDNs ((A≥δ>) plots for river networks are abruptly truncated, those for UDNs display exponential tempering [P>(A≥δ>)=aδ-ɛexp⁡>(-cδ>)]. The tempering parameter c decreases as the UDNs grow, implying that the distribution evolves in time to resemble those for river networks. However, the power law exponent ɛ for large UDNs tends to be greater than the range reported for river networks. Differences in generative processes and engineering design constraints contribute to observed differences in the evolution of UDNs and river networks, including subnet heterogeneity and nonrandom branching.

  19. Temporal Concurrent Constraint Programming

    DEFF Research Database (Denmark)

    Nielsen, Mogens; Palamidessi, Catuscia; Valencia, Frank Dan

    2002-01-01

    The ntcc calculus is a model of non-deterministic temporal concurrent constraint programming. In this paper we study behavioral notions for this calculus. In the underlying computational model, concurrent constraint processes are executed in discrete time intervals. The behavioral notions studied...

  20. Evaluating Distributed Timing Constraints

    DEFF Research Database (Denmark)

    Kristensen, C.H.; Drejer, N.

    1994-01-01

    In this paper we describe a solution to the problem of implementing time-optimal evaluation of timing constraints in distributed real-time systems.......In this paper we describe a solution to the problem of implementing time-optimal evaluation of timing constraints in distributed real-time systems....

  1. Theory of Constraints (TOC)

    DEFF Research Database (Denmark)

    Michelsen, Aage U.

    2004-01-01

    Tankegangen bag Theory of Constraints samt planlægningsprincippet Drum-Buffer-Rope. Endvidere skitse af The Thinking Process.......Tankegangen bag Theory of Constraints samt planlægningsprincippet Drum-Buffer-Rope. Endvidere skitse af The Thinking Process....

  2. Diffusion Processes Satisfying a Conservation Law Constraint

    Directory of Open Access Journals (Sweden)

    J. Bakosi

    2014-01-01

    Full Text Available We investigate coupled stochastic differential equations governing N nonnegative continuous random variables that satisfy a conservation principle. In various fields a conservation law requires a set of fluctuating variables to be nonnegative and (if appropriately normalized sum to one. As a result, any stochastic differential equation model to be realizable must not produce events outside of the allowed sample space. We develop a set of constraints on the drift and diffusion terms of such stochastic models to ensure that both the nonnegativity and the unit-sum conservation law constraints are satisfied as the variables evolve in time. We investigate the consequences of the developed constraints on the Fokker-Planck equation, the associated system of stochastic differential equations, and the evolution equations of the first four moments of the probability density function. We show that random variables, satisfying a conservation law constraint, represented by stochastic diffusion processes, must have diffusion terms that are coupled and nonlinear. The set of constraints developed enables the development of statistical representations of fluctuating variables satisfying a conservation law. We exemplify the results with the bivariate beta process and the multivariate Wright-Fisher, Dirichlet, and Lochner’s generalized Dirichlet processes.

  3. The 'E' factor -- evolving endodontics.

    Science.gov (United States)

    Hunter, M J

    2013-03-01

    Endodontics is a constantly developing field, with new instruments, preparation techniques and sealants competing with trusted and traditional approaches to tooth restoration. Thus general dental practitioners must question and understand the significance of these developments before adopting new practices. In view of this, the aim of this article, and the associated presentation at the 2013 British Dental Conference & Exhibition, is to provide an overview of endodontic methods and constantly evolving best practice. The presentation will review current preparation techniques, comparing rotary versus reciprocation, and question current trends in restoration of the endodontically treated tooth.

  4. Vocabulary Constraint on Texts

    Directory of Open Access Journals (Sweden)

    C. Sutarsyah

    2008-01-01

    Full Text Available This case study was carried out in the English Education Department of State University of Malang. The aim of the study was to identify and describe the vocabulary in the reading text and to seek if the text is useful for reading skill development. A descriptive qualitative design was applied to obtain the data. For this purpose, some available computer programs were used to find the description of vocabulary in the texts. It was found that the 20 texts containing 7,945 words are dominated by low frequency words which account for 16.97% of the words in the texts. The high frequency words occurring in the texts were dominated by function words. In the case of word levels, it was found that the texts have very limited number of words from GSL (General Service List of English Words (West, 1953. The proportion of the first 1,000 words of GSL only accounts for 44.6%. The data also show that the texts contain too large proportion of words which are not in the three levels (the first 2,000 and UWL. These words account for 26.44% of the running words in the texts.  It is believed that the constraints are due to the selection of the texts which are made of a series of short-unrelated texts. This kind of text is subject to the accumulation of low frequency words especially those of content words and limited of words from GSL. It could also defeat the development of students' reading skills and vocabulary enrichment.

  5. XEUS : the physics of the hot evolving universe

    NARCIS (Netherlands)

    Arnaud, Monique; Barcons, Xavier; Barret, Didier; Bautz, Marshall; Bellazzini, Ronaldo; Bleeker, Johan; Boehringer, Hans; Boller, Thomas; Brandt, William Nielsen; Cappi, Massimo; Carrera, Francisco; Comastri, Andrea; Costa, Enrico; Courvoisier, Thierry; de Korte, Piet; Dwelly, Tom; Fabian, Andrew; Flanagan, Kathryn; Gilli, Roberto; Griffiths, Richard; Hasinger, Gunther; Kaastra, Jelle; Kahn, Steve; Kelley, Richard; Kunieda, Hideyo; Makishima, Kazuo; Matt, Giorgio; Mendez, Mariano; Mitsuda, Kazuhisa; Nandra, Kirpal; Ohashi, Takaya; Page, Mathew; Palumbo, Giorgio; Pavlinsky, Mikhail; Sciortino, Salvatore; Smith, Alan; Strueder, Lothar; Takahashi, Tadayuki; Tuerler, Marc; Tuerner, Martin; Ueda, Yoshihiro; Vignali, Cristian; Vink, Jacco; Warwick, Robert; Watson, Mike; Willingale, Richard; Zhang, Shuang Nan

    This paper describes the next generation X-ray observatory XEUS which has been submitted to the European Space Agency in the framework of the Cosmic Vision 2015-2025 competition and has been selected for an assessment study. The paper summarizes the scientific goals and instrumental concepts of the

  6. Why did the savant syndrome not spread in the population? A psychiatric example of a developmental constraint

    NARCIS (Netherlands)

    Ploeger, A.; van der Maas, H.L.J.; Raijmakers, M.E.J.; Galis, F.

    2009-01-01

    A developmental constraint is a mechanism that limits the possibility of a phenotype to evolve. There is growing evidence for the existence of developmental constraints in the biological literature. We hypothesize that a developmental constraint prevents the savant syndrome, despite its positive

  7. Constraint-based reachability

    Directory of Open Access Journals (Sweden)

    Arnaud Gotlieb

    2013-02-01

    Full Text Available Iterative imperative programs can be considered as infinite-state systems computing over possibly unbounded domains. Studying reachability in these systems is challenging as it requires to deal with an infinite number of states with standard backward or forward exploration strategies. An approach that we call Constraint-based reachability, is proposed to address reachability problems by exploring program states using a constraint model of the whole program. The keypoint of the approach is to interpret imperative constructions such as conditionals, loops, array and memory manipulations with the fundamental notion of constraint over a computational domain. By combining constraint filtering and abstraction techniques, Constraint-based reachability is able to solve reachability problems which are usually outside the scope of backward or forward exploration strategies. This paper proposes an interpretation of classical filtering consistencies used in Constraint Programming as abstract domain computations, and shows how this approach can be used to produce a constraint solver that efficiently generates solutions for reachability problems that are unsolvable by other approaches.

  8. CONSTRAINTS AND PROBLEMS OF INTERNET SERVICES IN ...

    African Journals Online (AJOL)

    In spite of the benefits of the Internet to learning, teaching and research a number of difficulties still bedevil the provision of services in Nigeria. The objective of this study was to examine the constraints and problems of Internet Services at the Obafemi Awolowo University, Ile-Ife. Questionnaires were administered to ...

  9. Peripartum hysterectomy: an evolving picture.

    LENUS (Irish Health Repository)

    Turner, Michael J

    2012-02-01

    Peripartum hysterectomy (PH) is one of the obstetric catastrophes. Evidence is emerging that the role of PH in modern obstetrics is evolving. Improving management of postpartum hemorrhage and newer surgical techniques should decrease PH for uterine atony. Rising levels of repeat elective cesarean deliveries should decrease PH following uterine scar rupture in labor. Increasing cesarean rates, however, have led to an increase in the number of PHs for morbidly adherent placenta. In the case of uterine atony or rupture where PH is required, a subtotal PH is often sufficient. In the case of pathological placental localization involving the cervix, however, a total hysterectomy is required. Furthermore, the involvement of other pelvic structures may prospectively make the diagnosis difficult and the surgery challenging. If resources permit, PH for pathological placental localization merits a multidisciplinary approach. Despite advances in clinical practice, it is likely that peripartum hysterectomy will be more challenging for obstetricians in the future.

  10. Infrared spectroscopy of evolved objects

    International Nuclear Information System (INIS)

    Aitken, D.K.; Roche, P.F.

    1984-01-01

    In this review, the authors are concerned with spectroscopic observations of evolved objects made in the wavelength range 1-300μm. Spectroscopic observations can conveniently be divided into studies of narrow lines, bands and broader continua. The vibrational frequencies of molecular groups fall mainly in this spectral region and appear as vibration-rotation bands from the gas phase, and as less structured, but often broader, features from the solid state. Many ionic lines, including recombination lines of abundant species and fine structure lines of astrophysically important ions also appear in this region. The continuum can arise from a number of mechanisms - photospheric emission, radiation from dust, free-free transitions in ionized gas and non-thermal processes. (Auth.)

  11. Resources, constraints and capabilities

    NARCIS (Netherlands)

    Dhondt, S.; Oeij, P.R.A.; Schröder, A.

    2018-01-01

    Human and financial resources as well as organisational capabilities are needed to overcome the manifold constraints social innovators are facing. To unlock the potential of social innovation for the whole society new (social) innovation friendly environments and new governance structures

  12. Design with Nonlinear Constraints

    KAUST Repository

    Tang, Chengcheng

    2015-01-01

    . The first application is the design of meshes under both geometric and static constraints, including self-supporting polyhedral meshes that are not height fields. Then, with a formulation bridging mesh based and spline based representations, the application

  13. Dynamics and causality constraints

    International Nuclear Information System (INIS)

    Sousa, Manoelito M. de

    2001-04-01

    The physical meaning and the geometrical interpretation of causality implementation in classical field theories are discussed. Causality in field theory are kinematical constraints dynamically implemented via solutions of the field equation, but in a limit of zero-distance from the field sources part of these constraints carries a dynamical content that explains old problems of classical electrodynamics away with deep implications to the nature of physicals interactions. (author)

  14. Momentum constraint relaxation

    International Nuclear Information System (INIS)

    Marronetti, Pedro

    2006-01-01

    Full relativistic simulations in three dimensions invariably develop runaway modes that grow exponentially and are accompanied by violations of the Hamiltonian and momentum constraints. Recently, we introduced a numerical method (Hamiltonian relaxation) that greatly reduces the Hamiltonian constraint violation and helps improve the quality of the numerical model. We present here a method that controls the violation of the momentum constraint. The method is based on the addition of a longitudinal component to the traceless extrinsic curvature A ij -tilde, generated by a vector potential w i , as outlined by York. The components of w i are relaxed to solve approximately the momentum constraint equations, slowly pushing the evolution towards the space of solutions of the constraint equations. We test this method with simulations of binary neutron stars in circular orbits and show that it effectively controls the growth of the aforementioned violations. We also show that a full numerical enforcement of the constraints, as opposed to the gentle correction of the momentum relaxation scheme, results in the development of instabilities that stop the runs shortly

  15. Selection of new constraints

    International Nuclear Information System (INIS)

    Sugier, A.

    2003-01-01

    The selected new constraints should be consistent with the scale of concern i.e. be expressed roughly as fractions or multiples of the average annual background. They should take into account risk considerations and include the values of the currents limits, constraints and other action levels. The recommendation is to select four leading values for the new constraints: 500 mSv ( single event or in a decade) as a maximum value, 0.01 mSv/year as a minimum value; and two intermediate values: 20 mSv/year and 0.3 mSv/year. This new set of dose constraints, representing basic minimum standards of protection for the individuals taking into account the specificity of the exposure situations are thus coherent with the current values which can be found in ICRP Publications. A few warning need however to be noticed: There is no more multi sources limit set by ICRP. The coherence between the proposed value of dose constraint (20 mSv/year) and the current occupational dose limit of 20 mSv/year is valid only if the workers are exposed to one single source. When there is more than one source, it will be necessary to apportion. The value of 1000 mSv lifetimes used for relocation can be expressed into annual dose, which gives approximately 10 mSv/year and is coherent with the proposed dose constraint. (N.C.)

  16. Phloem physics: mechanisms, constraints, and perspectives.

    Science.gov (United States)

    Jensen, Kaare H

    2018-04-13

    Plants have evolved specialized vascular tissues for the distribution of energy, water, nutrients, and for communication. The phloem transports sugars from photosynthetic source regions (e.g. mature leaves) to sugar sinks (e.g. developing tissues such as buds, flowers, roots). Moreover, chemical signals such as hormones, RNAs and proteins also move in the phloem. Basic physical processes strongly limit phloem anatomy and function. This paper provides an overview of recent research and perspectives on phloem biomechanics and the physical constraints relevant to sugar transport in plants. Copyright © 2018 Elsevier Ltd. All rights reserved.

  17. Misconceptions and constraints

    International Nuclear Information System (INIS)

    Whitten, M.; Mahon, R.

    2005-01-01

    In theory, the sterile insect technique (SIT) is applicable to a wide variety of invertebrate pests. However, in practice, the approach has been successfully applied to only a few major pests. Chapters in this volume address possible reasons for this discrepancy, e.g. Klassen, Lance and McInnis, and Robinson and Hendrichs. The shortfall between theory and practice is partly due to the persistence of some common misconceptions, but it is mainly due to one constraint, or a combination of constraints, that are biological, financial, social or political in nature. This chapter's goal is to dispel some major misconceptions, and view the constraints as challenges to overcome, seeing them as opportunities to exploit. Some of the common misconceptions include: (1) released insects retain residual radiation, (2) females must be monogamous, (3) released males must be fully sterile, (4) eradication is the only goal, (5) the SIT is too sophisticated for developing countries, and (6) the SIT is not a component of an area-wide integrated pest management (AW-IPM) strategy. The more obvious constraints are the perceived high costs of the SIT, and the low competitiveness of released sterile males. The perceived high up-front costs of the SIT, their visibility, and the lack of private investment (compared with alternative suppression measures) emerge as serious constraints. Failure to appreciate the true nature of genetic approaches, such as the SIT, may pose a significant constraint to the wider adoption of the SIT and other genetically-based tactics, e.g. transgenic genetically modified organisms (GMOs). Lack of support for the necessary underpinning strategic research also appears to be an important constraint. Hence the case for extensive strategic research in ecology, population dynamics, genetics, and insect behaviour and nutrition is a compelling one. Raising the competitiveness of released sterile males remains the major research objective of the SIT. (author)

  18. Socioeconomic constraints to sustainable cocoyam production in the ...

    African Journals Online (AJOL)

    AGHOGHO A

    Full Length Research Paper ... 4Makerere University, Department of Crop Science, P. O. Box 7062, ... Cocoyam production, social and economic constraints, Lake Victoria region. .... available throughout the year and is also a stable source.

  19. Cosmological constraints on the properties of weakly interacting massive particles

    International Nuclear Information System (INIS)

    Steigman, G.; Turner, M.S.

    1984-10-01

    Considerations of the age and density of, as well as the evolution of structure in, the Universe lead to constraints on the masses and lifetimes of weakly interacting massive particles (WIMPs). 26 references

  20. Cosmological constraints on the properties of weakly interacting massive particles

    Energy Technology Data Exchange (ETDEWEB)

    Steigman, G.; Turner, M.S.

    1984-10-01

    Considerations of the age and density of, as well as the evolution of structure in, the Universe lead to constraints on the masses and lifetimes of weakly interacting massive particles (WIMPs). 26 references.

  1. The Relationship between Leisure Constraints, Constraint Negotiation Strategies and Facilitators with Recreational Sport Activity Participation of College Students

    Science.gov (United States)

    Kocak, Funda

    2017-01-01

    The aim of this study is to determine the constraints in participating the leisure activities for college students, the strategies of negotiation regarding these constraints and the relationship between the facilitators and activity participation. The population of the study consists of currently registered students from Ankara University.…

  2. CERN internal communication is evolving

    CERN Multimedia

    2016-01-01

    CERN news will now be regularly updated on the CERN People page (see here).      Dear readers, All over the world, communication is becoming increasingly instantaneous, with news published in real time on websites and social networks. In order to keep pace with these changes, CERN's internal communication is evolving too. From now on, you will be informed of what’s happening at CERN more often via the “CERN people” page, which will frequently be updated with news. The Bulletin is following this trend too: twice a month, we will compile the most important articles published on the CERN site, with a brand-new layout. You will receive an e-mail every two weeks as soon as this new form of the Bulletin is available. If you have interesting news or stories to share, tell us about them through the form at: https://communications.web.cern.ch/got-story-cern-website​. You can also find out about news from CERN in real time...

  3. Recommendation in evolving online networks

    Science.gov (United States)

    Hu, Xiao; Zeng, An; Shang, Ming-Sheng

    2016-02-01

    Recommender system is an effective tool to find the most relevant information for online users. By analyzing the historical selection records of users, recommender system predicts the most likely future links in the user-item network and accordingly constructs a personalized recommendation list for each user. So far, the recommendation process is mostly investigated in static user-item networks. In this paper, we propose a model which allows us to examine the performance of the state-of-the-art recommendation algorithms in evolving networks. We find that the recommendation accuracy in general decreases with time if the evolution of the online network fully depends on the recommendation. Interestingly, some randomness in users' choice can significantly improve the long-term accuracy of the recommendation algorithm. When a hybrid recommendation algorithm is applied, we find that the optimal parameter gradually shifts towards the diversity-favoring recommendation algorithm, indicating that recommendation diversity is essential to keep a high long-term recommendation accuracy. Finally, we confirm our conclusions by studying the recommendation on networks with the real evolution data.

  4. Evolving Capabilities for Virtual Globes

    Science.gov (United States)

    Glennon, A.

    2006-12-01

    Though thin-client spatial visualization software like Google Earth and NASA World Wind enjoy widespread popularity, a common criticism is their general lack of analytical functionality. This concern, however, is rapidly being addressed; standard and advanced geographic information system (GIS) capabilities are being developed for virtual globes--though not centralized into a single implementation or software package. The innovation is mostly originating from the user community. Three such capabilities relevant to the earth science, education, and emergency management communities are modeling dynamic spatial phenomena, real-time data collection and visualization, and multi-input collaborative databases. Modeling dynamic spatial phenomena has been facilitated through joining virtual globe geometry definitions--like KML--to relational databases. Real-time data collection uses short scripts to transform user-contributed data into a format usable by virtual globe software. Similarly, collaborative data collection for virtual globes has become possible by dynamically referencing online, multi-person spreadsheets. Examples of these functions include mapping flows within a karst watershed, real-time disaster assessment and visualization, and a collaborative geyser eruption spatial decision support system. Virtual globe applications will continue to evolve further analytical capabilities, more temporal data handling, and from nano to intergalactic scales. This progression opens education and research avenues in all scientific disciplines.

  5. Future Cosmological Constraints From Fast Radio Bursts

    Science.gov (United States)

    Walters, Anthony; Weltman, Amanda; Gaensler, B. M.; Ma, Yin-Zhe; Witzemann, Amadeus

    2018-03-01

    We consider the possible observation of fast radio bursts (FRBs) with planned future radio telescopes, and investigate how well the dispersions and redshifts of these signals might constrain cosmological parameters. We construct mock catalogs of FRB dispersion measure (DM) data and employ Markov Chain Monte Carlo analysis, with which we forecast and compare with existing constraints in the flat ΛCDM model, as well as some popular extensions that include dark energy equation of state and curvature parameters. We find that the scatter in DM observations caused by inhomogeneities in the intergalactic medium (IGM) poses a big challenge to the utility of FRBs as a cosmic probe. Only in the most optimistic case, with a high number of events and low IGM variance, do FRBs aid in improving current constraints. In particular, when FRBs are combined with CMB+BAO+SNe+H 0 data, we find the biggest improvement comes in the {{{Ω }}}{{b}}{h}2 constraint. Also, we find that the dark energy equation of state is poorly constrained, while the constraint on the curvature parameter, Ω k , shows some improvement when combined with current constraints. When FRBs are combined with future baryon acoustic oscillation (BAO) data from 21 cm Intensity Mapping, we find little improvement over the constraints from BAOs alone. However, the inclusion of FRBs introduces an additional parameter constraint, {{{Ω }}}{{b}}{h}2, which turns out to be comparable to existing constraints. This suggests that FRBs provide valuable information about the cosmological baryon density in the intermediate redshift universe, independent of high-redshift CMB data.

  6. Assembly constraints drive co-evolution among ribosomal constituents.

    Science.gov (United States)

    Mallik, Saurav; Akashi, Hiroshi; Kundu, Sudip

    2015-06-23

    Ribosome biogenesis, a central and essential cellular process, occurs through sequential association and mutual co-folding of protein-RNA constituents in a well-defined assembly pathway. Here, we construct a network of co-evolving nucleotide/amino acid residues within the ribosome and demonstrate that assembly constraints are strong predictors of co-evolutionary patterns. Predictors of co-evolution include a wide spectrum of structural reconstitution events, such as cooperativity phenomenon, protein-induced rRNA reconstitutions, molecular packing of different rRNA domains, protein-rRNA recognition, etc. A correlation between folding rate of small globular proteins and their topological features is known. We have introduced an analogous topological characteristic for co-evolutionary network of ribosome, which allows us to differentiate between rRNA regions subjected to rapid reconstitutions from those hindered by kinetic traps. Furthermore, co-evolutionary patterns provide a biological basis for deleterious mutation sites and further allow prediction of potential antibiotic targeting sites. Understanding assembly pathways of multicomponent macromolecules remains a key challenge in biophysics. Our study provides a 'proof of concept' that directly relates co-evolution to biophysical interactions during multicomponent assembly and suggests predictive power to identify candidates for critical functional interactions as well as for assembly-blocking antibiotic target sites. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

  7. Patterns of the cosmic microwave background from evolving string networks

    International Nuclear Information System (INIS)

    Bouchet, F.R.; Bennett, D.P.; Stebbins, A.

    1988-01-01

    A network of cosmic strings generated in the early Universe may still exist today. As the strings move across the sky, they produce, by gravitational lensing, a characteristic pattern of anisotropies in the temperature of the cosmic microwave background. The observed absence of such anisotropies places constraints on theories in which galaxy formation is seeded by strings, but it is anticipated that the next generation of experiments will detect them. (author)

  8. Integral constraints on perturbations of Robertson-Walker cosmologies

    International Nuclear Information System (INIS)

    Ellis, G.F.R.; Jaklitsch, M.J.

    1989-01-01

    Integral constraints occur in the case of spherically symmetric inhomogeneities in Robertson-Walker universes, and (according to Traschen) in the case of general perturbations of these models. It is shown that these constraints are the same in the case of spherical symmetry, and they are interpreted as 'fitting conditions', that is, as constraints on the background Robertson-Walker model rather than on the nature of inhomogeneities. These integral constraints significantly affect the interpretation of anisotropies in the cosmic microwave background radiation. 22 refs

  9. Idiopathic pulmonary fibrosis: evolving concepts.

    Science.gov (United States)

    Ryu, Jay H; Moua, Teng; Daniels, Craig E; Hartman, Thomas E; Yi, Eunhee S; Utz, James P; Limper, Andrew H

    2014-08-01

    Idiopathic pulmonary fibrosis (IPF) occurs predominantly in middle-aged and older adults and accounts for 20% to 30% of interstitial lung diseases. It is usually progressive, resulting in respiratory failure and death. Diagnostic criteria for IPF have evolved over the years, and IPF is currently defined as a disease characterized by the histopathologic pattern of usual interstitial pneumonia occurring in the absence of an identifiable cause of lung injury. Understanding of the pathogenesis of IPF has shifted away from chronic inflammation and toward dysregulated fibroproliferative repair in response to alveolar epithelial injury. Idiopathic pulmonary fibrosis is likely a heterogeneous disorder caused by various interactions between genetic components and environmental exposures. High-resolution computed tomography can be diagnostic in the presence of typical findings such as bilateral reticular opacities associated with traction bronchiectasis/bronchiolectasis in a predominantly basal and subpleural distribution, along with subpleural honeycombing. In other circumstances, a surgical lung biopsy may be needed. The clinical course of IPF can be unpredictable and may be punctuated by acute deteriorations (acute exacerbation). Although progress continues in unraveling the mechanisms of IPF, effective therapy has remained elusive. Thus, clinicians and patients need to reach informed decisions regarding management options including lung transplant. The findings in this review were based on a literature search of PubMed using the search terms idiopathic pulmonary fibrosis and usual interstitial pneumonia, limited to human studies in the English language published from January 1, 2000, through December 31, 2013, and supplemented by key references published before the year 2000. Copyright © 2014 Mayo Foundation for Medical Education and Research. Published by Elsevier Inc. All rights reserved.

  10. Occupational dose constraint

    International Nuclear Information System (INIS)

    Heilbron Filho, Paulo Fernando Lavalle; Xavier, Ana Maria

    2005-01-01

    The revision process of the international radiological protection regulations has resulted in the adoption of new concepts, such as practice, intervention, avoidable and restriction of dose (dose constraint). The latter deserving of special mention since it may involve reducing a priori of the dose limits established both for the public and to individuals occupationally exposed, values that can be further reduced, depending on the application of the principle of optimization. This article aims to present, with clarity, from the criteria adopted to define dose constraint values to the public, a methodology to establish the dose constraint values for occupationally exposed individuals, as well as an example of the application of this methodology to the practice of industrial radiography

  11. Psychological constraints on egalitarianism

    DEFF Research Database (Denmark)

    Kasperbauer, Tyler Joshua

    2015-01-01

    processes motivating people to resist various aspects of egalitarianism. I argue for two theses, one normative and one descriptive. The normative thesis holds that egalitarians must take psychological constraints into account when constructing egalitarian ideals. I draw from non-ideal theories in political...... philosophy, which aim to construct moral goals with current social and political constraints in mind, to argue that human psychology must be part of a non-ideal theory of egalitarianism. The descriptive thesis holds that the most fundamental psychological challenge to egalitarian ideals comes from what......Debates over egalitarianism for the most part are not concerned with constraints on achieving an egalitarian society, beyond discussions of the deficiencies of egalitarian theory itself. This paper looks beyond objections to egalitarianism as such and investigates the relevant psychological...

  12. Adjustment and Optimization of the Cropping Systems under Water Constraint

    Directory of Open Access Journals (Sweden)

    Pingli An

    2016-11-01

    Full Text Available The water constraint on agricultural production receives growing concern with the increasingly sharp contradiction between demand and supply of water resources. How to mitigate and adapt to potential water constraint is one of the key issues for ensuring food security and achieving sustainable agriculture in the context of climate change. It has been suggested that adjustment and optimization of cropping systems could be an effective measure to improve water management and ensure food security. However, a knowledge gap still exists in how to quantify potential water constraint and how to select appropriate cropping systems. Here, we proposed a concept of water constraint risk and developed an approach for the evaluation of the water constraint risks for agricultural production by performing a case study in Daxing District, Beijing, China. The results show that, over the whole growth period, the order of the water constraint risks of crops from high to low was wheat, rice, broomcorn, foxtail millet, summer soybean, summer peanut, spring corn, and summer corn, and the order of the water constraint risks of the cropping systems from high to low was winter wheat-summer grain crops, rice, broomcorn, foxtail millet, and spring corn. Our results are consistent with the actual evolving process of cropping system. This indicates that our proposed method is practicable to adjust and optimize the cropping systems to mitigate and adapt to potential water risks. This study provides an insight into the adjustment and optimization of cropping systems under resource constraints.

  13. Evolving Ecological Social Dilemmas: A Spatial Individual-Based Model for the Evolution of Cooperation with a Minimal Number of Parameters

    International Nuclear Information System (INIS)

    Fort, H.

    2007-01-01

    Cooperation, both intraspecific and interspecific, is a well-documented phenomenon in nature that is not well understood. Evolutionary game theory is a powerful tool to approach this problem. However, it has important limitations. First, very often it is not obvious which game is more appropriate to use. Second, in general, identical payoff matrices are assumed for all players, a situation that is highly unlikely in nature. Third, slight changes in these payoff values can dramatically alter the outcomes. Here, I use an evolutionary spatial model in which players do not have a universal payoff matrix, so no payoff parameters are required. Instead, each is equipped with random values for the payoffs, fulfilling the constraints that define the game(s). These payoff matrices evolve by natural selection. Two versions of this model are studied. First is a simpler one, with just one evolving payoff. Second is the full version, with all the four payoffs evolving. The fraction of cooperator agents converges in both versions to nonzero values. In the case of the full version, the initial heterogeneity disappears and the selected game is the stag Hunt

  14. Bayesian Methods and Universal Darwinism

    Science.gov (United States)

    Campbell, John

    2009-12-01

    Bayesian methods since the time of Laplace have been understood by their practitioners as closely aligned to the scientific method. Indeed a recent Champion of Bayesian methods, E. T. Jaynes, titled his textbook on the subject Probability Theory: the Logic of Science. Many philosophers of science including Karl Popper and Donald Campbell have interpreted the evolution of Science as a Darwinian process consisting of a `copy with selective retention' algorithm abstracted from Darwin's theory of Natural Selection. Arguments are presented for an isomorphism between Bayesian Methods and Darwinian processes. Universal Darwinism, as the term has been developed by Richard Dawkins, Daniel Dennett and Susan Blackmore, is the collection of scientific theories which explain the creation and evolution of their subject matter as due to the Operation of Darwinian processes. These subject matters span the fields of atomic physics, chemistry, biology and the social sciences. The principle of Maximum Entropy states that Systems will evolve to states of highest entropy subject to the constraints of scientific law. This principle may be inverted to provide illumination as to the nature of scientific law. Our best cosmological theories suggest the universe contained much less complexity during the period shortly after the Big Bang than it does at present. The scientific subject matter of atomic physics, chemistry, biology and the social sciences has been created since that time. An explanation is proposed for the existence of this subject matter as due to the evolution of constraints in the form of adaptations imposed on Maximum Entropy. It is argued these adaptations were discovered and instantiated through the Operations of a succession of Darwinian processes.

  15. WMAP constraints on the Cardassian model

    International Nuclear Information System (INIS)

    Sen, A.A.; Sen, S.

    2003-01-01

    We investigate the constraints on the Cardassian model using the recent results from the Wilkinson microwave anisotropy probe for the locations of the peaks of the cosmic microwave background (CMB) anisotropy spectrum. We find that the model is consistent with the recent observational data for a certain range of the model parameter n and the cosmological parameters. We find that the Cardassian model is favored compared to the ΛCDM model for a higher spectral index (n s ≅1) together with a lower value of the Hubble parameter h (h≤0.71). But for smaller values of n s , both ΛCDM and Cardassian models are equally favored. Also, irrespective of supernova constraints, CMB data alone predict the current acceleration of the Universe in this model. We have also studied the constraint on σ 8 , the rms density fluctuations at the 8h -1 Mpc scale

  16. Constraint-based scheduling applying constraint programming to scheduling problems

    CERN Document Server

    Baptiste, Philippe; Nuijten, Wim

    2001-01-01

    Constraint Programming is a problem-solving paradigm that establishes a clear distinction between two pivotal aspects of a problem: (1) a precise definition of the constraints that define the problem to be solved and (2) the algorithms and heuristics enabling the selection of decisions to solve the problem. It is because of these capabilities that Constraint Programming is increasingly being employed as a problem-solving tool to solve scheduling problems. Hence the development of Constraint-Based Scheduling as a field of study. The aim of this book is to provide an overview of the most widely used Constraint-Based Scheduling techniques. Following the principles of Constraint Programming, the book consists of three distinct parts: The first chapter introduces the basic principles of Constraint Programming and provides a model of the constraints that are the most often encountered in scheduling problems. Chapters 2, 3, 4, and 5 are focused on the propagation of resource constraints, which usually are responsibl...

  17. Constraints on Dbar uplifts

    International Nuclear Information System (INIS)

    Alwis, S.P. de

    2016-01-01

    We discuss constraints on KKLT/KKLMMT and LVS scenarios that use anti-branes to get an uplift to a deSitter vacuum, coming from requiring the validity of an effective field theory description of the physics. We find these are not always satisfied or are hard to satisfy.

  18. Ecosystems emerging. 5: Constraints

    Czech Academy of Sciences Publication Activity Database

    Patten, B. C.; Straškraba, Milan; Jorgensen, S. E.

    2011-01-01

    Roč. 222, č. 16 (2011), s. 2945-2972 ISSN 0304-3800 Institutional research plan: CEZ:AV0Z50070508 Keywords : constraint * epistemic * ontic Subject RIV: EH - Ecology, Behaviour Impact factor: 2.326, year: 2011 http://www.sciencedirect.com/science/article/pii/S0304380011002274

  19. Constraints and Ambiguity

    DEFF Research Database (Denmark)

    Dove, Graham; Biskjær, Michael Mose; Lundqvist, Caroline Emilie

    2017-01-01

    groups of students building three models each. We studied groups building with traditional plastic bricks and also using a digital environment. The building tasks students undertake, and our subsequent analysis, are informed by the role constraints and ambiguity play in creative processes. Based...

  20. Star clusters in evolving galaxies

    Science.gov (United States)

    Renaud, Florent

    2018-04-01

    Their ubiquity and extreme densities make star clusters probes of prime importance of galaxy evolution. Old globular clusters keep imprints of the physical conditions of their assembly in the early Universe, and younger stellar objects, observationally resolved, tell us about the mechanisms at stake in their formation. Yet, we still do not understand the diversity involved: why is star cluster formation limited to 105M⊙ objects in the Milky Way, while some dwarf galaxies like NGC 1705 are able to produce clusters 10 times more massive? Why do dwarfs generally host a higher specific frequency of clusters than larger galaxies? How to connect the present-day, often resolved, stellar systems to the formation of globular clusters at high redshift? And how do these links depend on the galactic and cosmological environments of these clusters? In this review, I present recent advances on star cluster formation and evolution, in galactic and cosmological context. The emphasis is put on the theory, formation scenarios and the effects of the environment on the evolution of the global properties of clusters. A few open questions are identified.

  1. Evolving Technologies: A View to Tomorrow

    Science.gov (United States)

    Tamarkin, Molly; Rodrigo, Shelley

    2011-01-01

    Technology leaders must participate in strategy creation as well as operational delivery within higher education institutions. The future of higher education--the view to tomorrow--is irrevocably integrated and intertwined with evolving technologies. This article focuses on two specific evolving technologies: (1) alternative IT sourcing; and (2)…

  2. Graphical constraints: a graphical user interface for constraint problems

    OpenAIRE

    Vieira, Nelson Manuel Marques

    2015-01-01

    A constraint satisfaction problem is a classical artificial intelligence paradigm characterized by a set of variables (each variable with an associated domain of possible values), and a set of constraints that specify relations among subsets of these variables. Solutions are assignments of values to all variables that satisfy all the constraints. Many real world problems may be modelled by means of constraints. The range of problems that can use this representation is very diverse and embrace...

  3. Evolvability Search: Directly Selecting for Evolvability in order to Study and Produce It

    DEFF Research Database (Denmark)

    Mengistu, Henok; Lehman, Joel Anthony; Clune, Jeff

    2016-01-01

    of evolvable digital phenotypes. Although some types of selection in evolutionary computation indirectly encourage evolvability, one unexplored possibility is to directly select for evolvability. To do so, we estimate an individual's future potential for diversity by calculating the behavioral diversity of its...... immediate offspring, and select organisms with increased offspring variation. While the technique is computationally expensive, we hypothesized that direct selection would better encourage evolvability than indirect methods. Experiments in two evolutionary robotics domains confirm this hypothesis: in both...... domains, such Evolvability Search produces solutions with higher evolvability than those produced with Novelty Search or traditional objective-based search algorithms. Further experiments demonstrate that the higher evolvability produced by Evolvability Search in a training environment also generalizes...

  4. Distance Constraint Satisfaction Problems

    Science.gov (United States)

    Bodirsky, Manuel; Dalmau, Victor; Martin, Barnaby; Pinsker, Michael

    We study the complexity of constraint satisfaction problems for templates Γ that are first-order definable in ({ Z}; {suc}), the integers with the successor relation. Assuming a widely believed conjecture from finite domain constraint satisfaction (we require the tractability conjecture by Bulatov, Jeavons and Krokhin in the special case of transitive finite templates), we provide a full classification for the case that Γ is locally finite (i.e., the Gaifman graph of Γ has finite degree). We show that one of the following is true: The structure Γ is homomorphically equivalent to a structure with a certain majority polymorphism (which we call modular median) and CSP(Γ) can be solved in polynomial time, or Γ is homomorphically equivalent to a finite transitive structure, or CSP(Γ) is NP-complete.

  5. Constraint-based scheduling

    Science.gov (United States)

    Zweben, Monte

    1993-01-01

    The GERRY scheduling system developed by NASA Ames with assistance from the Lockheed Space Operations Company, and the Lockheed Artificial Intelligence Center, uses a method called constraint-based iterative repair. Using this technique, one encodes both hard rules and preference criteria into data structures called constraints. GERRY repeatedly attempts to improve schedules by seeking repairs for violated constraints. The system provides a general scheduling framework which is being tested on two NASA applications. The larger of the two is the Space Shuttle Ground Processing problem which entails the scheduling of all the inspection, repair, and maintenance tasks required to prepare the orbiter for flight. The other application involves power allocation for the NASA Ames wind tunnels. Here the system will be used to schedule wind tunnel tests with the goal of minimizing power costs. In this paper, we describe the GERRY system and its application to the Space Shuttle problem. We also speculate as to how the system would be used for manufacturing, transportation, and military problems.

  6. Evolving Levels for Super Mario Bros Using Grammatical Evolution

    DEFF Research Database (Denmark)

    Shaker, Noor; Nicolau, Miguel; Yannakakis, Georgios N.

    2012-01-01

    This paper presents the use of design grammars to evolve playable 2D platform levels through grammatical evolution (GE). Representing levels using design grammars allows simple encoding of important level design constraints, and allows remarkably compact descriptions of large spaces of levels....... The expressive range of the GE-based level generator is analyzed and quantitatively compared to other feature-based and the original level generators by means of aesthetic and similarity based measures. The analysis reveals strengths and shortcomings of each generator and provides a general frame- work...... for comparing content generated by different generators. The approach presented can be used as an assistive tool by game designers to compare and analyze generators’ capabilities within the same game genre....

  7. The Effect of Some Constraints on Mathematics Instructors' Problem ...

    African Journals Online (AJOL)

    This study was designed to examine the effect of perceived constraints on four universities mathematics department instructors' classroom practices of problem solving in teaching mathematics. To this end, the target population of the study includes mathematics instructors in the Amhara Regional state universities. From a ...

  8. The Sloan Digital Sky Survey Quasar Lens Search. VI. Constraints on Dark Energy and the Evolution of Massive Galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Oguri, Masamune [Univ. of Tokyo (Japan); et al.

    2012-05-01

    We present a statistical analysis of the final lens sample from the Sloan Digital Sky Survey Quasar Lens Search (SQLS). The number distribution of a complete subsample of 19 lensed quasars selected from 50,836 source quasars is compared with theoretical expectations, with particular attention to the selection function. Assuming that the velocity function of galaxies does not evolve with redshift, the SQLS sample constrains the cosmological constant to \\Omega_\\Lambda=0.79^{+0.06}_{-0.07}(stat.)^{+0.06}_{-0.06}(syst.) for a flat universe. The dark energy equation of state is found to be consistent with w=-1 when the SQLS is combined with constraints from baryon acoustic oscillation (BAO) measurements or results from the Wilkinson Microwave Anisotropy Probe (WMAP). We also obtain simultaneous constraints on cosmological parameters and redshift evolution of the galaxy velocity function, finding no evidence for redshift evolution at z<1 in any combinations of constraints. For instance, number density evolution quantified as \

  9. Efficient Searching with Linear Constraints

    DEFF Research Database (Denmark)

    Agarwal, Pankaj K.; Arge, Lars Allan; Erickson, Jeff

    2000-01-01

    We show how to preprocess a set S of points in d into an external memory data structure that efficiently supports linear-constraint queries. Each query is in the form of a linear constraint xd a0+∑d−1i=1 aixi; the data structure must report all the points of S that satisfy the constraint. This pr...

  10. Deepening Contractions and Collateral Constraints

    DEFF Research Database (Denmark)

    Jensen, Henrik; Ravn, Søren Hove; Santoro, Emiliano

    and occasionally non-binding credit constraints. Easier credit access increases the likelihood that constraints become slack in the face of expansionary shocks, while contractionary shocks are further amplified due to tighter constraints. As a result, busts gradually become deeper than booms. Based...

  11. Predator confusion is sufficient to evolve swarming behaviour.

    Science.gov (United States)

    Olson, Randal S; Hintze, Arend; Dyer, Fred C; Knoester, David B; Adami, Christoph

    2013-08-06

    Swarming behaviours in animals have been extensively studied owing to their implications for the evolution of cooperation, social cognition and predator-prey dynamics. An important goal of these studies is discerning which evolutionary pressures favour the formation of swarms. One hypothesis is that swarms arise because the presence of multiple moving prey in swarms causes confusion for attacking predators, but it remains unclear how important this selective force is. Using an evolutionary model of a predator-prey system, we show that predator confusion provides a sufficient selection pressure to evolve swarming behaviour in prey. Furthermore, we demonstrate that the evolutionary effect of predator confusion on prey could in turn exert pressure on the structure of the predator's visual field, favouring the frontally oriented, high-resolution visual systems commonly observed in predators that feed on swarming animals. Finally, we provide evidence that when prey evolve swarming in response to predator confusion, there is a change in the shape of the functional response curve describing the predator's consumption rate as prey density increases. Thus, we show that a relatively simple perceptual constraint--predator confusion--could have pervasive evolutionary effects on prey behaviour, predator sensory mechanisms and the ecological interactions between predators and prey.

  12. Sex determination: ways to evolve a hermaphrodite.

    OpenAIRE

    Braendle , Christian; Félix , Marie-Anne

    2006-01-01

    Most species of the nematode genus Caenorhabditis reproduce through males and females; C. elegans and C. briggsae, however, produce self-fertile hermaphrodites instead of females. These transitions to hermaphroditism evolved convergently through distinct modifications of germline sex determination mechanisms.

  13. WSC-07: Evolving the Web Services Challenge

    NARCIS (Netherlands)

    Blake, M. Brian; Cheung, William K.W.; Jaeger, Michael C.; Wombacher, Andreas

    Service-oriented architecture (SOA) is an evolving architectural paradigm where businesses can expose their capabilities as modular, network-accessible software services. By decomposing capabilities into modular services, organizations can share their offerings at multiple levels of granularity

  14. Marshal: Maintaining Evolving Models, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — SIFT proposes to design and develop the Marshal system, a mixed-initiative tool for maintaining task models over the course of evolving missions. Marshal-enabled...

  15. Satcom access in the Evolved Packet Core

    NARCIS (Netherlands)

    Cano Soveri, M.D.; Norp, A.H.J.; Popova, M.P.

    2011-01-01

    Satellite communications (Satcom) networks are increasingly integrating with terrestrial communications networks, namely Next Generation Networks (NGN). In the area of NGN the Evolved Packet Core (EPC) is a new network architecture that can support multiple access technologies. When Satcom is

  16. Satcom access in the evolved packet core

    NARCIS (Netherlands)

    Cano, M.D.; Norp, A.H.J.; Popova, M.P.

    2012-01-01

    Satellite communications (Satcom) networks are increasingly integrating with terrestrial communications networks, namely Next Generation Networks (NGN). In the area of NGN the Evolved Packet Core (EPC) is a new network architecture that can support multiple access technologies. When Satcom is

  17. Evolving effective incremental SAT solvers with GP

    OpenAIRE

    Bader, Mohamed; Poli, R.

    2008-01-01

    Hyper-Heuristics could simply be defined as heuristics to choose other heuristics, and it is a way of combining existing heuristics to generate new ones. In a Hyper-Heuristic framework, the framework is used for evolving effective incremental (Inc*) solvers for SAT. We test the evolved heuristics (IncHH) against other known local search heuristics on a variety of benchmark SAT problems.

  18. Design with Nonlinear Constraints

    KAUST Repository

    Tang, Chengcheng

    2015-12-10

    Most modern industrial and architectural designs need to satisfy the requirements of their targeted performance and respect the limitations of available fabrication technologies. At the same time, they should reflect the artistic considerations and personal taste of the designers, which cannot be simply formulated as optimization goals with single best solutions. This thesis aims at a general, flexible yet e cient computational framework for interactive creation, exploration and discovery of serviceable, constructible, and stylish designs. By formulating nonlinear engineering considerations as linear or quadratic expressions by introducing auxiliary variables, the constrained space could be e ciently accessed by the proposed algorithm Guided Projection, with the guidance of aesthetic formulations. The approach is introduced through applications in different scenarios, its effectiveness is demonstrated by examples that were difficult or even impossible to be computationally designed before. The first application is the design of meshes under both geometric and static constraints, including self-supporting polyhedral meshes that are not height fields. Then, with a formulation bridging mesh based and spline based representations, the application is extended to developable surfaces including origami with curved creases. Finally, general approaches to extend hard constraints and soft energies are discussed, followed by a concluding remark outlooking possible future studies.

  19. Searching for genomic constraints

    Energy Technology Data Exchange (ETDEWEB)

    Lio` , P [Cambridge, Univ. (United Kingdom). Genetics Dept.; Ruffo, S [Florence, Univ. (Italy). Fac. di Ingegneria. Dipt. di Energetica ` S. Stecco`

    1998-01-01

    The authors have analyzed general properties of very long DNA sequences belonging to simple and complex organisms, by using different correlation methods. They have distinguished those base compositional rules that concern the entire genome which they call `genomic constraints` from the rules that depend on the `external natural selection` acting on single genes, i. e. protein-centered constraints. They show that G + C content, purine / pyrimidine distributions and biological complexity of the organism are the most important factors which determine base compositional rules and genome complexity. Three main facts are here reported: bacteria with high G + C content have more restrictions on base composition than those with low G + C content; at constant G + C content more complex organisms, ranging from prokaryotes to higher eukaryotes (e.g. human) display an increase of repeats 10-20 nucleotides long, which are also partly responsible for long-range correlations; work selection of length 3 to 10 is stronger in human and in bacteria for two distinct reasons. With respect to previous studies, they have also compared the genomic sequence of the archeon Methanococcus jannaschii with those of bacteria and eukaryotes: it shows sometimes an intermediate statistical behaviour.

  20. Searching for genomic constraints

    International Nuclear Information System (INIS)

    Lio', P.; Ruffo, S.

    1998-01-01

    The authors have analyzed general properties of very long DNA sequences belonging to simple and complex organisms, by using different correlation methods. They have distinguished those base compositional rules that concern the entire genome which they call 'genomic constraints' from the rules that depend on the 'external natural selection' acting on single genes, i. e. protein-centered constraints. They show that G + C content, purine / pyrimidine distributions and biological complexity of the organism are the most important factors which determine base compositional rules and genome complexity. Three main facts are here reported: bacteria with high G + C content have more restrictions on base composition than those with low G + C content; at constant G + C content more complex organisms, ranging from prokaryotes to higher eukaryotes (e.g. human) display an increase of repeats 10-20 nucleotides long, which are also partly responsible for long-range correlations; work selection of length 3 to 10 is stronger in human and in bacteria for two distinct reasons. With respect to previous studies, they have also compared the genomic sequence of the archeon Methanococcus jannaschii with those of bacteria and eukaryotes: it shows sometimes an intermediate statistical behaviour

  1. The evolving integrated vascular surgery residency curriculum.

    Science.gov (United States)

    Smith, Brigitte K; Greenberg, Jacob A; Mitchell, Erica L

    2014-10-01

    Since their introduction several years ago, integrated (0 + 5) vascular surgery residency programs are being increasingly developed across the country. To date, however, there is no defined "universal" curriculum for these programs and each program is responsible for creating its own curriculum. The aim of this study was to review the experiences of current 0 + 5 program directors (PDs) to determine what factors contributed to the curricular development within their institution. Semistructured interviews were conducted with 0 + 5 PDs to explore their experiences with program development, factors influencing the latter, and rationale for current curricula. The interview script was loosely structured to explore several factors including time of incoming residents' first exposure to the vascular surgical service, timing and rationale behind the timing of core surgical rotations throughout the 5 year program, educational value of nonsurgical rotations, opportunities for leadership and scholarly activity, and influence the general surgery program and institutional climate had on curricular structure. All interviews were conducted by a single interviewer. All interviews were qualitatively analyzed using emergent theme analysis. Twenty-six 0 + 5 PDs participated in the study. A total of 69% believed establishing professional identity early reduces resident attrition and recommend starting incoming trainees on vascular surgical services. Sixty-two percent spread core surgical rotations over the first 3 years to optimize general surgical exposure and most of the programs have eliminated specific rotations, as they were not considered valuable to the goals of training. Factors considered most important by PDs in curricular development include building on existing institutional opportunities (96%), avoiding rotations considered unsuccessful by "experienced" programs (92%), and maintaining a good working relationship with general surgery (77%). Fifty-eight percent of

  2. Pairwise Constraint-Guided Sparse Learning for Feature Selection.

    Science.gov (United States)

    Liu, Mingxia; Zhang, Daoqiang

    2016-01-01

    Feature selection aims to identify the most informative features for a compact and accurate data representation. As typical supervised feature selection methods, Lasso and its variants using L1-norm-based regularization terms have received much attention in recent studies, most of which use class labels as supervised information. Besides class labels, there are other types of supervised information, e.g., pairwise constraints that specify whether a pair of data samples belong to the same class (must-link constraint) or different classes (cannot-link constraint). However, most of existing L1-norm-based sparse learning methods do not take advantage of the pairwise constraints that provide us weak and more general supervised information. For addressing that problem, we propose a pairwise constraint-guided sparse (CGS) learning method for feature selection, where the must-link and the cannot-link constraints are used as discriminative regularization terms that directly concentrate on the local discriminative structure of data. Furthermore, we develop two variants of CGS, including: 1) semi-supervised CGS that utilizes labeled data, pairwise constraints, and unlabeled data and 2) ensemble CGS that uses the ensemble of pairwise constraint sets. We conduct a series of experiments on a number of data sets from University of California-Irvine machine learning repository, a gene expression data set, two real-world neuroimaging-based classification tasks, and two large-scale attribute classification tasks. Experimental results demonstrate the efficacy of our proposed methods, compared with several established feature selection methods.

  3. Supergravity constraints on monojets

    International Nuclear Information System (INIS)

    Nandi, S.

    1986-01-01

    In the standard model, supplemented by N = 1 minimal supergravity, all the supersymmetric particle masses can be expressed in terms of a few unknown parameters. The resulting mass relations, and the laboratory and the cosmological bounds on these superpartner masses are used to put constraints on the supersymmetric origin of the CERN monojets. The latest MAC data at PEP excludes the scalar quarks, of masses up to 45 GeV, as the origin of these monojets. The cosmological bounds, for a stable photino, excludes the mass range necessary for the light gluino-heavy squark production interpretation. These difficulties can be avoided by going beyond the minimal supergravity theory. Irrespective of the monojets, the importance of the stable γ as the source of the cosmological dark matter is emphasized

  4. Temporal Concurrent Constraint Programming

    DEFF Research Database (Denmark)

    Valencia, Frank Dan

    Concurrent constraint programming (ccp) is a formalism for concurrency in which agents interact with one another by telling (adding) and asking (reading) information in a shared medium. Temporal ccp extends ccp by allowing agents to be constrained by time conditions. This dissertation studies...... temporal ccp by developing a process calculus called ntcc. The ntcc calculus generalizes the tcc model, the latter being a temporal ccp model for deterministic and synchronouss timed reactive systems. The calculus is built upon few basic ideas but it captures several aspects of timed systems. As tcc, ntcc...... structures, robotic devises, multi-agent systems and music applications. The calculus is provided with a denotational semantics that captures the reactive computations of processes in the presence of arbitrary environments. The denotation is proven to be fully-abstract for a substantial fragment...

  5. Minimal Flavor Constraints for Technicolor

    DEFF Research Database (Denmark)

    Sakuma, Hidenori; Sannino, Francesco

    2010-01-01

    We analyze the constraints on the the vacuum polarization of the standard model gauge bosons from a minimal set of flavor observables valid for a general class of models of dynamical electroweak symmetry breaking. We will show that the constraints have a strong impact on the self-coupling and mas......We analyze the constraints on the the vacuum polarization of the standard model gauge bosons from a minimal set of flavor observables valid for a general class of models of dynamical electroweak symmetry breaking. We will show that the constraints have a strong impact on the self...

  6. Social Constraints on Animate Vision

    National Research Council Canada - National Science Library

    Breazeal, Cynthia; Edsinger, Aaron; Fitzpatrick, Paul; Scassellati, Brian

    2000-01-01

    .... In humanoid robotic systems, or in any animate vision system that interacts with people, social dynamics provide additional levels of constraint and provide additional opportunities for processing economy...

  7. Evolving Intelligent Systems Methodology and Applications

    CERN Document Server

    Angelov, Plamen; Kasabov, Nik

    2010-01-01

    From theory to techniques, the first all-in-one resource for EIS. There is a clear demand in advanced process industries, defense, and Internet and communication (VoIP) applications for intelligent yet adaptive/evolving systems. Evolving Intelligent Systems is the first self- contained volume that covers this newly established concept in its entirety, from a systematic methodology to case studies to industrial applications. Featuring chapters written by leading world experts, it addresses the progress, trends, and major achievements in this emerging research field, with a strong emphasis on th

  8. Interactively Evolving Compositional Sound Synthesis Networks

    DEFF Research Database (Denmark)

    Jónsson, Björn Þór; Hoover, Amy K.; Risi, Sebastian

    2015-01-01

    the space of potential sounds that can be generated through such compositional sound synthesis networks (CSSNs). To study the effect of evolution on subjective appreciation, participants in a listener study ranked evolved timbres by personal preference, resulting in preferences skewed toward the first......While the success of electronic music often relies on the uniqueness and quality of selected timbres, many musicians struggle with complicated and expensive equipment and techniques to create their desired sounds. Instead, this paper presents a technique for producing novel timbres that are evolved...

  9. Modifier constraint in alkali borophosphate glasses using topological constraint theory

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiang [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Zeng, Huidan, E-mail: hdzeng@ecust.edu.cn [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Jiang, Qi [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Zhao, Donghui [Unifrax Corporation, Niagara Falls, NY 14305 (United States); Chen, Guorong [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Wang, Zhaofeng; Sun, Luyi [Department of Chemical & Biomolecular Engineering and Polymer Program, Institute of Materials Science, University of Connecticut, Storrs, CT 06269 (United States); Chen, Jianding [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China)

    2016-12-01

    In recent years, composition-dependent properties of glasses have been successfully predicted using the topological constraint theory. The constraints of the glass network are derived from two main parts: network formers and network modifiers. The constraints of the network formers can be calculated on the basis of the topological structure of the glass. However, the latter cannot be accurately calculated in this way, because of the existing of ionic bonds. In this paper, the constraints of the modifier ions in phosphate glasses were thoroughly investigated using the topological constraint theory. The results show that the constraints of the modifier ions are gradually increased with the addition of alkali oxides. Furthermore, an improved topological constraint theory for borophosphate glasses is proposed by taking the composition-dependent constraints of the network modifiers into consideration. The proposed theory is subsequently evaluated by analyzing the composition dependence of the glass transition temperature in alkali borophosphate glasses. This method is supposed to be extended to other similar glass systems containing alkali ions.

  10. Seismological Constraints on Geodynamics

    Science.gov (United States)

    Lomnitz, C.

    2004-12-01

    Earth is an open thermodynamic system radiating heat energy into space. A transition from geostatic earth models such as PREM to geodynamical models is needed. We discuss possible thermodynamic constraints on the variables that govern the distribution of forces and flows in the deep Earth. In this paper we assume that the temperature distribution is time-invariant, so that all flows vanish at steady state except for the heat flow Jq per unit area (Kuiken, 1994). Superscript 0 will refer to the steady state while x denotes the excited state of the system. We may write σ 0=(J{q}0ṡX{q}0)/T where Xq is the conjugate force corresponding to Jq, and σ is the rate of entropy production per unit volume. Consider now what happens after the occurrence of an earthquake at time t=0 and location (0,0,0). The earthquake introduces a stress drop Δ P(x,y,z) at all points of the system. Response flows are directed along the gradients toward the epicentral area, and the entropy production will increase with time as (Prigogine, 1947) σ x(t)=σ 0+α {1}/(t+β )+α {2}/(t+β )2+etc A seismological constraint on the parameters may be obtained from Omori's empirical relation N(t)=p/(t+q) where N(t) is the number of aftershocks at time t following the main shock. It may be assumed that p/q\\sim\\alpha_{1}/\\beta times a constant. Another useful constraint is the Mexican-hat geometry of the seismic transient as obtained e.g. from InSAR radar interferometry. For strike-slip events such as Landers the distribution of \\DeltaP is quadrantal, and an oval-shaped seismicity gap develops about the epicenter. A weak outer triggering maxiμm is found at a distance of about 17 fault lengths. Such patterns may be extracted from earthquake catalogs by statistical analysis (Lomnitz, 1996). Finally, the energy of the perturbation must be at least equal to the recovery energy. The total energy expended in an aftershock sequence can be found approximately by integrating the local contribution over

  11. On the Benefits of Divergent Search for Evolved Representations

    DEFF Research Database (Denmark)

    Lehman, Joel; Risi, Sebastian; Stanley, Kenneth O

    2012-01-01

    Evolved representations in evolutionary computation are often fragile, which can impede representation-dependent mechanisms such as self-adaptation. In contrast, evolved representations in nature are robust, evolvable, and creatively exploit available representational features. This paper provide...

  12. Preface: evolving rotifers, evolving science: Proceedings of the XIV International Rotifer Symposium

    Czech Academy of Sciences Publication Activity Database

    Devetter, Miloslav; Fontaneto, D.; Jersabek, Ch.D.; Welch, D.B.M.; May, L.; Walsh, E.J.

    2017-01-01

    Roč. 796, č. 1 (2017), s. 1-6 ISSN 0018-8158 Institutional support: RVO:60077344 Keywords : evolving rotifers * 14th International Rotifer Symposium * evolving science Subject RIV: EG - Zoology OBOR OECD: Zoology Impact factor: 2.056, year: 2016

  13. Constraints on Gauge Field Production during Inflation

    DEFF Research Database (Denmark)

    Nurmi, Sami; Sloth, Martin Snoager

    2014-01-01

    In order to gain new insights into the gauge field couplings in the early universe, we consider the constraints on gauge field production during inflation imposed by requiring that their effect on the CMB anisotropies are subdominant. In particular, we calculate systematically the bispectrum...... of the primordial curvature perturbation induced by the presence of vector gauge fields during inflation. Using a model independent parametrization in terms of magnetic non-linearity parameters, we calculate for the first time the contribution to the bispectrum from the cross correlation between the inflaton...

  14. Views on Evolvability of Embedded Systems

    NARCIS (Netherlands)

    Laar, P. van de; Punter, T.

    2011-01-01

    Evolvability, the ability to respond effectively to change, represents a major challenge to today's high-end embedded systems, such as those developed in the medical domain by Philips Healthcare. These systems are typically developed by multi-disciplinary teams, located around the world, and are in

  15. Views on evolvability of embedded systems

    NARCIS (Netherlands)

    Laar, van de P.J.L.J.; Punter, H.T.

    2011-01-01

    Evolvability, the ability to respond effectively to change, represents a major challenge to today's high-end embedded systems, such as those developed in the medical domain by Philips Healthcare. These systems are typically developed by multi-disciplinary teams, located around the world, and are in

  16. Designing Garments to Evolve Over Time

    DEFF Research Database (Denmark)

    Riisberg, Vibeke; Grose, Lynda

    2017-01-01

    This paper proposes a REDO of the current fashion paradigm by investigating how garments might be designed to evolve over time. The purpose is to discuss ways of expanding the traditional role of the designer to include temporal dimensions of creating, producing and using clothes and to suggest...... to a REDO of design education, to further research and the future fashion and textile industry....

  17. Continual Learning through Evolvable Neural Turing Machines

    DEFF Research Database (Denmark)

    Lüders, Benno; Schläger, Mikkel; Risi, Sebastian

    2016-01-01

    Continual learning, i.e. the ability to sequentially learn tasks without catastrophic forgetting of previously learned ones, is an important open challenge in machine learning. In this paper we take a step in this direction by showing that the recently proposed Evolving Neural Turing Machine (ENTM...

  18. Did Language Evolve Like the Vertebrate Eye?

    Science.gov (United States)

    Botha, Rudolf P.

    2002-01-01

    Offers a critical appraisal of the way in which the idea that human language or some of its features evolved like the vertebrate eye by natural selection is articulated in Pinker and Bloom's (1990) selectionist account of language evolution. Argues that this account is less than insightful because it fails to draw some of the conceptual…

  19. Observational constraints on interstellar chemistry

    International Nuclear Information System (INIS)

    Winnewisser, G.

    1984-01-01

    The author points out presently existing observational constraints in the detection of interstellar molecular species and the limits they may cast on our knowledge of interstellar chemistry. The constraints which arise from the molecular side are summarised and some technical difficulties encountered in detecting new species are discussed. Some implications for our understanding of molecular formation processes are considered. (Auth.)

  20. Market segmentation using perceived constraints

    Science.gov (United States)

    Jinhee Jun; Gerard Kyle; Andrew Mowen

    2008-01-01

    We examined the practical utility of segmenting potential visitors to Cleveland Metroparks using their constraint profiles. Our analysis identified three segments based on their scores on the dimensions of constraints: Other priorities--visitors who scored the highest on 'other priorities' dimension; Highly Constrained--visitors who scored relatively high on...

  1. Fixed Costs and Hours Constraints

    Science.gov (United States)

    Johnson, William R.

    2011-01-01

    Hours constraints are typically identified by worker responses to questions asking whether they would prefer a job with more hours and more pay or fewer hours and less pay. Because jobs with different hours but the same rate of pay may be infeasible when there are fixed costs of employment or mandatory overtime premia, the constraint in those…

  2. An Introduction to 'Creativity Constraints'

    DEFF Research Database (Denmark)

    Onarheim, Balder; Biskjær, Michael Mose

    2013-01-01

    Constraints play a vital role as both restrainers and enablers in innovation processes by governing what the creative agent/s can and cannot do, and what the output can and cannot be. Notions of constraints are common in creativity research, but current contributions are highly dispersed due to n...

  3. Constraint Programming for Context Comprehension

    DEFF Research Database (Denmark)

    Christiansen, Henning

    2014-01-01

    A close similarity is demonstrated between context comprehension, such as discourse analysis, and constraint programming. The constraint store takes the role of a growing knowledge base learned throughout the discourse, and a suitable con- straint solver does the job of incorporating new pieces...

  4. Brain evolution and development: adaptation, allometry and constraint

    Science.gov (United States)

    Barton, Robert A.

    2016-01-01

    Phenotypic traits are products of two processes: evolution and development. But how do these processes combine to produce integrated phenotypes? Comparative studies identify consistent patterns of covariation, or allometries, between brain and body size, and between brain components, indicating the presence of significant constraints limiting independent evolution of separate parts. These constraints are poorly understood, but in principle could be either developmental or functional. The developmental constraints hypothesis suggests that individual components (brain and body size, or individual brain components) tend to evolve together because natural selection operates on relatively simple developmental mechanisms that affect the growth of all parts in a concerted manner. The functional constraints hypothesis suggests that correlated change reflects the action of selection on distributed functional systems connecting the different sub-components, predicting more complex patterns of mosaic change at the level of the functional systems and more complex genetic and developmental mechanisms. These hypotheses are not mutually exclusive but make different predictions. We review recent genetic and neurodevelopmental evidence, concluding that functional rather than developmental constraints are the main cause of the observed patterns. PMID:27629025

  5. Extreme scenarios: the tightest possible constraints on the power spectrum due to primordial black holes

    Science.gov (United States)

    Cole, Philippa S.; Byrnes, Christian T.

    2018-02-01

    Observational constraints on the abundance of primordial black holes (PBHs) constrain the allowed amplitude of the primordial power spectrum on both the smallest and the largest ranges of scales, covering over 20 decades from 1‑1020/ Mpc. Despite tight constraints on the allowed fraction of PBHs at their time of formation near horizon entry in the early Universe, the corresponding constraints on the primordial power spectrum are quite weak, typically Script PRlesssim 10‑2 assuming Gaussian perturbations. Motivated by recent claims that the evaporation of just one PBH would destabilise the Higgs vacuum and collapse the Universe, we calculate the constraints which follow from assuming there are zero PBHs within the observable Universe. Even if evaporating PBHs do not collapse the Universe, this scenario represents the ultimate limit of observational constraints. Constraints can be extended on to smaller scales right down to the horizon scale at the end of inflation, but where power spectrum constraints already exist they do not tighten significantly, even though the constraint on PBH abundance can decrease by up to 46 orders of magnitude. This shows that no future improvement in observational constraints can ever lead to a significant tightening in constraints on inflation (via the power spectrum amplitude). The power spectrum constraints are weak because an order unity perturbation is required in order to overcome pressure forces. We therefore consider an early matter dominated era, during which exponentially more PBHs form for the same initial conditions. We show this leads to far tighter constraints, which approach Script PRlesssim10‑9, albeit over a smaller range of scales and are very sensitive to when the early matter dominated era ends. Finally, we show that an extended early matter era is incompatible with the argument that an evaporating PBH would destroy the Universe, unless the power spectrum amplitude decreases by up to ten orders of magnitude.

  6. Natural Constraints to Species Diversification.

    Directory of Open Access Journals (Sweden)

    Eric Lewitus

    2016-08-01

    Full Text Available Identifying modes of species diversification is fundamental to our understanding of how biodiversity changes over evolutionary time. Diversification modes are captured in species phylogenies, but characterizing the landscape of diversification has been limited by the analytical tools available for directly comparing phylogenetic trees of groups of organisms. Here, we use a novel, non-parametric approach and 214 family-level phylogenies of vertebrates representing over 500 million years of evolution to identify major diversification modes, to characterize phylogenetic space, and to evaluate the bounds and central tendencies of species diversification. We identify five principal patterns of diversification to which all vertebrate families hold. These patterns, mapped onto multidimensional space, constitute a phylogenetic space with distinct properties. Firstly, phylogenetic space occupies only a portion of all possible tree space, showing family-level phylogenies to be constrained to a limited range of diversification patterns. Secondly, the geometry of phylogenetic space is delimited by quantifiable trade-offs in tree size and the heterogeneity and stem-to-tip distribution of branching events. These trade-offs are indicative of the instability of certain diversification patterns and effectively bound speciation rates (for successful clades within upper and lower limits. Finally, both the constrained range and geometry of phylogenetic space are established by the differential effects of macroevolutionary processes on patterns of diversification. Given these properties, we show that the average path through phylogenetic space over evolutionary time traverses several diversification stages, each of which is defined by a different principal pattern of diversification and directed by a different macroevolutionary process. The identification of universal patterns and natural constraints to diversification provides a foundation for understanding the

  7. Natural Constraints to Species Diversification.

    Science.gov (United States)

    Lewitus, Eric; Morlon, Hélène

    2016-08-01

    Identifying modes of species diversification is fundamental to our understanding of how biodiversity changes over evolutionary time. Diversification modes are captured in species phylogenies, but characterizing the landscape of diversification has been limited by the analytical tools available for directly comparing phylogenetic trees of groups of organisms. Here, we use a novel, non-parametric approach and 214 family-level phylogenies of vertebrates representing over 500 million years of evolution to identify major diversification modes, to characterize phylogenetic space, and to evaluate the bounds and central tendencies of species diversification. We identify five principal patterns of diversification to which all vertebrate families hold. These patterns, mapped onto multidimensional space, constitute a phylogenetic space with distinct properties. Firstly, phylogenetic space occupies only a portion of all possible tree space, showing family-level phylogenies to be constrained to a limited range of diversification patterns. Secondly, the geometry of phylogenetic space is delimited by quantifiable trade-offs in tree size and the heterogeneity and stem-to-tip distribution of branching events. These trade-offs are indicative of the instability of certain diversification patterns and effectively bound speciation rates (for successful clades) within upper and lower limits. Finally, both the constrained range and geometry of phylogenetic space are established by the differential effects of macroevolutionary processes on patterns of diversification. Given these properties, we show that the average path through phylogenetic space over evolutionary time traverses several diversification stages, each of which is defined by a different principal pattern of diversification and directed by a different macroevolutionary process. The identification of universal patterns and natural constraints to diversification provides a foundation for understanding the deep-time evolution of

  8. Natural Constraints to Species Diversification

    Science.gov (United States)

    Lewitus, Eric; Morlon, Hélène

    2016-01-01

    Identifying modes of species diversification is fundamental to our understanding of how biodiversity changes over evolutionary time. Diversification modes are captured in species phylogenies, but characterizing the landscape of diversification has been limited by the analytical tools available for directly comparing phylogenetic trees of groups of organisms. Here, we use a novel, non-parametric approach and 214 family-level phylogenies of vertebrates representing over 500 million years of evolution to identify major diversification modes, to characterize phylogenetic space, and to evaluate the bounds and central tendencies of species diversification. We identify five principal patterns of diversification to which all vertebrate families hold. These patterns, mapped onto multidimensional space, constitute a phylogenetic space with distinct properties. Firstly, phylogenetic space occupies only a portion of all possible tree space, showing family-level phylogenies to be constrained to a limited range of diversification patterns. Secondly, the geometry of phylogenetic space is delimited by quantifiable trade-offs in tree size and the heterogeneity and stem-to-tip distribution of branching events. These trade-offs are indicative of the instability of certain diversification patterns and effectively bound speciation rates (for successful clades) within upper and lower limits. Finally, both the constrained range and geometry of phylogenetic space are established by the differential effects of macroevolutionary processes on patterns of diversification. Given these properties, we show that the average path through phylogenetic space over evolutionary time traverses several diversification stages, each of which is defined by a different principal pattern of diversification and directed by a different macroevolutionary process. The identification of universal patterns and natural constraints to diversification provides a foundation for understanding the deep-time evolution of

  9. Evolution of cyclic mixmaster universes with noncomoving radiation

    Science.gov (United States)

    Ganguly, Chandrima; Barrow, John D.

    2017-12-01

    We study a model of a cyclic, spatially homogeneous, anisotropic, "mixmaster" universe of Bianchi type IX, containing a radiation field with noncomoving ("tilted" with respect to the tetrad frame of reference) velocities and vorticity. We employ a combination of numerical and approximate analytic methods to investigate the consequences of the second law of thermodynamics on the evolution. We model a smooth cycle-to-cycle evolution of the mixmaster universe, bouncing at a finite minimum, by the device of adding a comoving "ghost" field with negative energy density. In the absence of a cosmological constant, an increase in entropy, injected at the start of each cycle, causes an increase in the volume maxima, increasing approach to flatness, falling velocities and vorticities, and growing anisotropy at the expansion maxima of successive cycles. We find that the velocities oscillate rapidly as they evolve and change logarithmically in time relative to the expansion volume. When the conservation of momentum and angular momentum constraints are imposed, the spatial components of these velocities fall to smaller values when the entropy density increases, and vice versa. Isotropization is found to occur when a positive cosmological constant is added because the sequence of oscillations ends and the dynamics expand forever, evolving towards a quasi-de Sitter asymptote with constant velocity amplitudes. The case of a single cycle of evolution with a negative cosmological constant added is also studied.

  10. Hypermagnetic gyrotropy, inflation and the baryon asymmetry of the Universe

    CERN Document Server

    Giovannini, Massimo

    2015-01-01

    We investigate the production of the hypermagnetic gyrotropy when the electric and magnetic gauge couplings evolve at different rates, as it happens in the the relativistic theory of the Van der Waals forces. If a pseudo-scalar interaction breaks the duality symmetry of the corresponding equations, the gyrotropic configurations of the hypermagnetic fields can be amplified from the vacuum during an inflationary stage of expansion. After charting the parameter space of the model in terms of the rates of evolution of the magnetic and electric gauge couplings, we identify the regions where the gyrotropy is sufficiently intense to seed the baryon asymmetry of the Universe at the electroweak epoch while the backreaction constraints, the strong coupling bounds and the other astrophysical limits are concurrently satisfied.

  11. Cosmological Constraints on Mirror Matter Parameters

    International Nuclear Information System (INIS)

    Wallemacq, Quentin; Ciarcelluti, Paolo

    2014-01-01

    Up-to-date estimates of the cosmological parameters are presented as a result of numerical simulations of cosmic microwave background and large scale structure, considering a flat Universe in which the dark matter is made entirely or partly of mirror matter, and the primordial perturbations are scalar adiabatic and in linear regime. A statistical analysis using the Markov Chain Monte Carlo method allows to obtain constraints of the cosmological parameters. As a result, we show that a Universe with pure mirror dark matter is statistically equivalent to the case of an admixture with cold dark matter. The upper limits for the ratio of the temperatures of ordinary and mirror sectors are around 0.3 for both the cosmological models, which show the presence of a dominant fraction of mirror matter, 0.06≲Ω_m_i_r_r_o_rh"2≲0.12.

  12. Psychiatric Epidemiology: The University Paradigm

    Science.gov (United States)

    Favazza, Armando R.

    1976-01-01

    In an effort to provide a meaningful didactic experience within the constraint of limited teaching hours, the author searched for a "community" which might be examined. A community fulfilling the established criteria for trainees in a university training program is the university itself. Its use is described. (LBH)

  13. The evolving definition of systemic arterial hypertension.

    Science.gov (United States)

    Ram, C Venkata S; Giles, Thomas D

    2010-05-01

    Systemic hypertension is an important risk factor for premature cardiovascular disease. Hypertension also contributes to excessive morbidity and mortality. Whereas excellent therapeutic options are available to treat hypertension, there is an unsettled issue about the very definition of hypertension. At what level of blood pressure should we treat hypertension? Does the definition of hypertension change in the presence of co-morbid conditions? This article covers in detail the evolving concepts in the diagnosis and management of hypertension.

  14. The evolving epidemiology of inflammatory bowel disease.

    LENUS (Irish Health Repository)

    Shanahan, Fergus

    2009-07-01

    Epidemiologic studies in inflammatory bowel disease (IBD) include assessments of disease burden and evolving patterns of disease presentation. Although it is hoped that sound epidemiologic studies provide aetiological clues, traditional risk factor-based epidemiology has provided limited insights into either Crohn\\'s disease or ulcerative colitis etiopathogenesis. In this update, we will summarize how the changing epidemiology of IBD associated with modernization can be reconciled with current concepts of disease mechanisms and will discuss studies of clinically significant comorbidity in IBD.

  15. Quantum games on evolving random networks

    OpenAIRE

    Pawela, Łukasz

    2015-01-01

    We study the advantages of quantum strategies in evolutionary social dilemmas on evolving random networks. We focus our study on the two-player games: prisoner's dilemma, snowdrift and stag-hunt games. The obtained result show the benefits of quantum strategies for the prisoner's dilemma game. For the other two games, we obtain regions of parameters where the quantum strategies dominate, as well as regions where the classical strategies coexist.

  16. Evolving artificial metalloenzymes via random mutagenesis

    Science.gov (United States)

    Yang, Hao; Swartz, Alan M.; Park, Hyun June; Srivastava, Poonam; Ellis-Guardiola, Ken; Upp, David M.; Lee, Gihoon; Belsare, Ketaki; Gu, Yifan; Zhang, Chen; Moellering, Raymond E.; Lewis, Jared C.

    2018-03-01

    Random mutagenesis has the potential to optimize the efficiency and selectivity of protein catalysts without requiring detailed knowledge of protein structure; however, introducing synthetic metal cofactors complicates the expression and screening of enzyme libraries, and activity arising from free cofactor must be eliminated. Here we report an efficient platform to create and screen libraries of artificial metalloenzymes (ArMs) via random mutagenesis, which we use to evolve highly selective dirhodium cyclopropanases. Error-prone PCR and combinatorial codon mutagenesis enabled multiplexed analysis of random mutations, including at sites distal to the putative ArM active site that are difficult to identify using targeted mutagenesis approaches. Variants that exhibited significantly improved selectivity for each of the cyclopropane product enantiomers were identified, and higher activity than previously reported ArM cyclopropanases obtained via targeted mutagenesis was also observed. This improved selectivity carried over to other dirhodium-catalysed transformations, including N-H, S-H and Si-H insertion, demonstrating that ArMs evolved for one reaction can serve as starting points to evolve catalysts for others.

  17. Constraints on Majorana dark matter from a fourth lepton family

    DEFF Research Database (Denmark)

    Hapola, T.; Jarvinen, M.; Kouvaris, C.

    2014-01-01

    We study the possibility of dark matter in the form of heavy neutrinos from a fourth lepton family with helicity suppressed couplings such that dark matter is produced thermally via annihilations in the early Universe. We present all possible constraints for this scenario coming from LHC...... account for the dark matter abundance....

  18. The willingness and constraints to routing HIV screening among ...

    African Journals Online (AJOL)

    Methods: This descriptive cross- sectional study on 312 pregnant women attending antenatal clinic at Nnamdi Azikiwe University Teaching Hospital Nnewi, was carried out, to evaluate the knowledge of HIV/AIDS, the practice of voluntary HIV testing and also determine the constraints and motivation to voluntary HIV testing.

  19. International Conference “Ultraviolet Properties of Evolved Stellar Populations

    CERN Document Server

    Chavez Dagostino, Miguel

    2009-01-01

    This book presents an up-to-date collection of reviews and contributed articles in the field of ultraviolet astronomy. Its content has been mainly motivated by the recent access to the rest frame UV light of distant red galaxies, gained through large optical facilities. This driveway has derived in a renewed interest on the stars that presumably dominate or have important effects on the integrated UV properties of evolved systems of the nearby and faraway Universe. The topics included in this volume extend from the fresh spectroscopic analyses of high redshift early-type galaxies observed with the 8-10m class telescopes to the fundamental outcomes from various satellites, from the long-lived International Ultraviolet Explorer to current facilities, such as the Galaxy Evolution Explorer. This is one of the few volumes published in recent years devoted to UV astronomical research and the only one dedicated to the properties of evolved stellar populations at these wavelengths. This contemporary panorama will be ...

  20. Applying ant colony optimization metaheuristic to solve forest transportation planning problems with side constraints

    Science.gov (United States)

    Marco A. Contreras; Woodam Chung; Greg Jones

    2008-01-01

    Forest transportation planning problems (FTPP) have evolved from considering only the financial aspects of timber management to more holistic problems that also consider the environmental impacts of roads. These additional requirements have introduced side constraints, making FTPP larger and more complex. Mixed-integer programming (MIP) has been used to solve FTPP, but...

  1. Machine tongues. X. Constraint languages

    Energy Technology Data Exchange (ETDEWEB)

    Levitt, D.

    Constraint languages and programming environments will help the designer produce a lucid description of a problem domain, and then of particular situations and problems in it. Early versions of these languages were given descriptions of real world domain constraints, like the operation of electrical and mechanical parts. More recently, the author has automated a vocabulary for describing musical jazz phrases, using constraint language as a jazz improviser. General constraint languages will handle all of these domains. Once the model is in place, the system will connect built-in code fragments and algorithms to answer questions about situations; that is, to help solve problems. Bugs will surface not in code, but in designs themselves. 15 references.

  2. Colon trauma: primary repair evolving as the standard of care.

    Science.gov (United States)

    Muffoletto, J. P.; Tate, J. S.

    1996-01-01

    This study reviewed the management of colon injuries treated at the trauma surgical service, University of Nevada Medical Center between 1987 and 1992. Sixty-six patients sustained either blunt or penetrating colon injuries during the study period. The patients were divided into two groups: patients who underwent diverting colostomies and patients who underwent primary repair. Both groups were equally matched in terms of colon injury severity as well as trauma scores. The results indicated that primary colon repair was as safe if not safer than colostomy with less complications and at lower costs. The authors conclude that primary repair should be reevaluated in a critical manner as an evolving standard of care. PMID:8855649

  3. Fluid convection, constraint and causation

    Science.gov (United States)

    Bishop, Robert C.

    2012-01-01

    Complexity—nonlinear dynamics for my purposes in this essay—is rich with metaphysical and epistemological implications but is receiving sustained philosophical analysis only recently. I will explore some of the subtleties of causation and constraint in Rayleigh–Bénard convection as an example of a complex phenomenon, and extract some lessons for further philosophical reflection on top-down constraint and causation particularly with respect to causal foundationalism. PMID:23386955

  4. Sustaining an International Partnership: An Evolving Collaboration

    Science.gov (United States)

    Pierson, Melinda R.; Myck-Wayne, Janice; Stang, Kristin K.; Basinska, Anna

    2015-01-01

    Universities across the United States have an increasing interest in international education. Increasing global awareness through educational collaborations will promote greater cross-cultural understanding and build effective relationships with diverse communities. This paper documents one university's effort to build an effective international…

  5. Evolution of female carotenoid coloration by sexual constraint in Carduelis finches

    Directory of Open Access Journals (Sweden)

    Cardoso Gonçalo C

    2010-03-01

    Full Text Available Abstract Background Females often express the same ornaments as males to a similar or lesser degree. Female ornaments can be adaptive, but little is known regarding their origins and mode of evolution. Current utility does not imply evolutionary causation, and therefore it is possible that female ornamentation evolved due to selection on females, as a correlated response to selection on males (sexual constraint, or a combination of both. We tested these ideas simulating simple models for the evolution of male and female correlated traits, and compared their predictions against the coloration of finches in the genus Carduelis. Results For carotenoid-based ornamental coloration, a model of sexual constraint on females fits the Carduelis data well. The two alternative models (sexual constraint on males, and mutual constraint were rejected as causing the similarities in carotenoid coloration between males and females. For melanin coloration, the correlation between the sexes was weaker, indicating that males and females evolved independently to a greater extent. Conclusions This indicates that sexual constraint on females was an important mechanism for the evolution of ornamental carotenoid coloration in females, but less so for melanin coloration. This does not mean that female carotenoid coloration is non-adaptive or maladaptive, because sexual dichromatism could evolve if it were maladaptive. It suggests, however, that most evolution of female carotenoid coloration was male-driven and, when adaptive, may not be an adaptation stricto sensu.

  6. Curvature constraints from the causal entropic principle

    International Nuclear Information System (INIS)

    Bozek, Brandon; Albrecht, Andreas; Phillips, Daniel

    2009-01-01

    Current cosmological observations indicate a preference for a cosmological constant that is drastically smaller than what can be explained by conventional particle physics. The causal entropic principle (Bousso et al.) provides an alternative approach to anthropic attempts to predict our observed value of the cosmological constant by calculating the entropy created within a causal diamond. We have extended this work to use the causal entropic principle to predict the preferred curvature within the 'multiverse'. We have found that values larger than ρ k =40ρ m are disfavored by more than 99.99% peak value at ρ Λ =7.9x10 -123 and ρ k =4.3ρ m for open universes. For universes that allow only positive curvature or both positive and negative curvature, we find a correlation between curvature and dark energy that leads to an extended region of preferred values. Our universe is found to be disfavored to an extent depending on the priors on curvature. We also provide a comparison to previous anthropic constraints on open universes and discuss future directions for this work.

  7. The impact of a sustainability constraint on the mean-tracking error efficient frontier

    NARCIS (Netherlands)

    Boudt, K.M.R.; Cornelissen, J.; Croux, C.

    2013-01-01

    Most socially responsible investment funds combine a sustainability objective with a tracking error constraint. We characterize the impact of a sustainability constraint on the mean-tracking error efficient frontier and illustrate this on a universe of US stocks for the period 2003-2010. © 2013

  8. Revealing evolved massive stars with Spitzer

    Science.gov (United States)

    Gvaramadze, V. V.; Kniazev, A. Y.; Fabrika, S.

    2010-06-01

    Massive evolved stars lose a large fraction of their mass via copious stellar wind or instant outbursts. During certain evolutionary phases, they can be identified by the presence of their circumstellar nebulae. In this paper, we present the results of a search for compact nebulae (reminiscent of circumstellar nebulae around evolved massive stars) using archival 24-μm data obtained with the Multiband Imaging Photometer for Spitzer. We have discovered 115 nebulae, most of which bear a striking resemblance to the circumstellar nebulae associated with luminous blue variables (LBVs) and late WN-type (WNL) Wolf-Rayet (WR) stars in the Milky Way and the Large Magellanic Cloud (LMC). We interpret this similarity as an indication that the central stars of detected nebulae are either LBVs or related evolved massive stars. Our interpretation is supported by follow-up spectroscopy of two dozen of these central stars, most of which turn out to be either candidate LBVs (cLBVs), blue supergiants or WNL stars. We expect that the forthcoming spectroscopy of the remaining objects from our list, accompanied by the spectrophotometric monitoring of the already discovered cLBVs, will further increase the known population of Galactic LBVs. This, in turn, will have profound consequences for better understanding the LBV phenomenon and its role in the transition between hydrogen-burning O stars and helium-burning WR stars. We also report on the detection of an arc-like structure attached to the cLBV HD 326823 and an arc associated with the LBV R99 (HD 269445) in the LMC. Partially based on observations collected at the German-Spanish Astronomical Centre, Calar Alto, jointly operated by the Max-Planck-Institut für Astronomie Heidelberg and the Instituto de Astrofísica de Andalucía (CSIC). E-mail: vgvaram@mx.iki.rssi.ru (VVG); akniazev@saao.ac.za (AYK); fabrika@sao.ru (SF)

  9. Evolving Random Forest for Preference Learning

    DEFF Research Database (Denmark)

    Abou-Zleikha, Mohamed; Shaker, Noor

    2015-01-01

    This paper introduces a novel approach for pairwise preference learning through a combination of an evolutionary method and random forest. Grammatical evolution is used to describe the structure of the trees in the Random Forest (RF) and to handle the process of evolution. Evolved random forests ...... obtained for predicting pairwise self-reports of users for the three emotional states engagement, frustration and challenge show very promising results that are comparable and in some cases superior to those obtained from state-of-the-art methods....

  10. An evolving network model with community structure

    International Nuclear Information System (INIS)

    Li Chunguang; Maini, Philip K

    2005-01-01

    Many social and biological networks consist of communities-groups of nodes within which connections are dense, but between which connections are sparser. Recently, there has been considerable interest in designing algorithms for detecting community structures in real-world complex networks. In this paper, we propose an evolving network model which exhibits community structure. The network model is based on the inner-community preferential attachment and inter-community preferential attachment mechanisms. The degree distributions of this network model are analysed based on a mean-field method. Theoretical results and numerical simulations indicate that this network model has community structure and scale-free properties

  11. Radio Imaging of Envelopes of Evolved Stars

    Science.gov (United States)

    Cotton, Bill

    2018-04-01

    This talk will cover imaging of stellar envelopes using radio VLBI techniques; special attention will be paid to the technical differences between radio and optical/IR interferomery. Radio heterodyne receivers allow a straightforward way to derive spectral cubes and full polarization observations. Milliarcsecond resolution of very bright, i.e. non thermal, emission of molecular masers in the envelopes of evolved stars can be achieved using VLBI techniques with baselines of thousands of km. Emission from SiO, H2O and OH masers are commonly seen at increasing distance from the photosphere. The very narrow maser lines allow accurate measurements of the velocity field within the emitting region.

  12. Mobile computing acceptance grows as applications evolve.

    Science.gov (United States)

    Porn, Louis M; Patrick, Kelly

    2002-01-01

    Handheld devices are becoming more cost-effective to own, and their use in healthcare environments is increasing. Handheld devices currently are being used for e-prescribing, charge capture, and accessing daily schedules and reference tools. Future applications may include education on medications, dictation, order entry, and test-results reporting. Selecting the right handheld device requires careful analysis of current and future applications, as well as vendor expertise. It is important to recognize the technology will continue to evolve over the next three years.

  13. Evolved Minimal Frustration in Multifunctional Biomolecules.

    Science.gov (United States)

    Röder, Konstantin; Wales, David J

    2018-05-25

    Protein folding is often viewed in terms of a funnelled potential or free energy landscape. A variety of experiments now indicate the existence of multifunnel landscapes, associated with multifunctional biomolecules. Here, we present evidence that these systems have evolved to exhibit the minimal number of funnels required to fulfil their cellular functions, suggesting an extension to the principle of minimum frustration. We find that minimal disruptive mutations result in additional funnels, and the associated structural ensembles become more diverse. The same trends are observed in an atomic cluster. These observations suggest guidelines for rational design of engineered multifunctional biomolecules.

  14. SALT Spectroscopy of Evolved Massive Stars

    Science.gov (United States)

    Kniazev, A. Y.; Gvaramadze, V. V.; Berdnikov, L. N.

    2017-06-01

    Long-slit spectroscopy with the Southern African Large Telescope (SALT) of central stars of mid-infrared nebulae detected with the Spitzer Space Telescope and Wide-Field Infrared Survey Explorer (WISE) led to the discovery of numerous candidate luminous blue variables (cLBVs) and other rare evolved massive stars. With the recent advent of the SALT fiber-fed high-resolution echelle spectrograph (HRS), a new perspective for the study of these interesting objects is appeared. Using the HRS we obtained spectra of a dozen newly identified massive stars. Some results on the recently identified cLBV Hen 3-729 are presented.

  15. ASTEROSEISMOLOGY OF EVOLVED STARS WITH KEPLER: A NEW WAY TO CONSTRAIN STELLAR INTERIORS USING MODE INERTIAS

    Energy Technology Data Exchange (ETDEWEB)

    Benomar, O.; Bedding, T. R.; Stello, D. [Sydney Institute for Astronomy (SIfA), School of Physics, University of Sydney, NSW 2006 (Australia); Belkacem, K. [LESIA, Observatoire de Paris, CNRS UMR 8109, Université Paris Diderot, 5 place J. Janssen, F-92195 Meudon (France); Di Mauro, M. P. [INAF-IAPS Istituto di Astrofisica e Planetologia Spaziali, Via del Fosso del Cavaliere 100, I-00133 Roma (Italy); Ventura, R. [INAF-Astrophyscial Observatory of Catania, Via S. Sofia 78, I-95123 Catania (Italy); Mosser, B.; Goupil, M. J.; Samadi, R. [Department of Astronomy, The University of Tokyo, Tokyo 113-0033 (Japan); Garcia, R. A. [Laboratoire AIM, CEA/DSM-CNRS-Université Paris Diderot, IRFU/SAp, Centre de Saclay, F-91191 Gif-sur-Yvette Cedex (France)

    2014-02-01

    The asteroseismology of evolved solar-like stars is experiencing growing interest due to the wealth of observational data from space-borne instruments such as the CoRoT and Kepler spacecraft. In particular, the recent detection of mixed modes, which probe both the innermost and uppermost layers of stars, paves the way for inferring the internal structure of stars along their evolution through the subgiant and red giant phases. Mixed modes can also place stringent constraints on the physics of such stars and on their global properties (mass, age, etc.). Here, using two Kepler stars (KIC 4351319 and KIC 6442183), we demonstrate that measurements of mixed mode characteristics allow us to estimate the mode inertias, providing a new and additional diagnostics on the mode trapping and subsequently on the internal structure of evolved stars. We however stress that the accuracy may be sensitive to non-adiabatic effects.

  16. Evolving controllers for a homogeneous system of physical robots: structured cooperation with minimal sensors.

    Science.gov (United States)

    Quinn, Matt; Smith, Lincoln; Mayley, Giles; Husbands, Phil

    2003-10-15

    We report on recent work in which we employed artificial evolution to design neural network controllers for small, homogeneous teams of mobile autonomous robots. The robots were evolved to perform a formation-movement task from random starting positions, equipped only with infrared sensors. The dual constraints of homogeneity and minimal sensors make this a non-trivial task. We describe the behaviour of a successful system in which robots adopt and maintain functionally distinct roles in order to achieve the task. We believe this to be the first example of the use of artificial evolution to design coordinated, cooperative behaviour for real robots.

  17. BOOK REVIEW: OPENING SCIENCE, THE EVOLVING GUIDE ...

    Science.gov (United States)

    The way we get our funding, collaborate, do our research, and get the word out has evolved over hundreds of years but we can imagine a more open science world, largely facilitated by the internet. The movement towards this more open way of doing and presenting science is coming, and it is not taking hundreds of years. If you are interested in these trends, and would like to find out more about where this is all headed and what it means to you, consider downloding Opening Science, edited by Sönke Bartling and Sascha Friesike, subtitled The Evolving Guide on How the Internet is Changing Research, Collaboration, and Scholarly Publishing. In 26 chapters by various authors from a range of disciplines the book explores the developing world of open science, starting from the first scientific revolution and bringing us to the next scientific revolution, sometimes referred to as “Science 2.0”. Some of the articles deal with the impact of the changing landscape of how science is done, looking at the impact of open science on Academia, or journal publishing, or medical research. Many of the articles look at the uses, pitfalls, and impact of specific tools, like microblogging (think Twitter), social networking, and reference management. There is lots of discussion and definition of terms you might use or misuse like “altmetrics” and “impact factor”. Science will probably never be completely open, and Twitter will probably never replace the journal article,

  18. Evolving NASA's Earth Science Data Systems

    Science.gov (United States)

    Walter, J.; Behnke, J.; Murphy, K. J.; Lowe, D. R.

    2013-12-01

    NASA's Earth Science Data and Information System Project (ESDIS) is charged with managing, maintaining, and evolving NASA's Earth Observing System Data and Information System (EOSDIS) and is responsible for processing, archiving, and distributing NASA Earth science data. The system supports a multitude of missions and serves diverse science research and other user communities. Keeping up with ever-changing information technology and figuring out how to leverage those changes across such a large system in order to continuously improve and meet the needs of a diverse user community is a significant challenge. Maintaining and evolving the system architecture and infrastructure is a continuous and multi-layered effort. It requires a balance between a "top down" management paradigm that provides a coherent system view and maintaining the managerial, technological, and functional independence of the individual system elements. This presentation will describe some of the key elements of the current system architecture, some of the strategies and processes we employ to meet these challenges, current and future challenges, and some ideas for meeting those challenges.

  19. The Comet Cometh: Evolving Developmental Systems.

    Science.gov (United States)

    Jaeger, Johannes; Laubichler, Manfred; Callebaut, Werner

    In a recent opinion piece, Denis Duboule has claimed that the increasing shift towards systems biology is driving evolutionary and developmental biology apart, and that a true reunification of these two disciplines within the framework of evolutionary developmental biology (EvoDevo) may easily take another 100 years. He identifies methodological, epistemological, and social differences as causes for this supposed separation. Our article provides a contrasting view. We argue that Duboule's prediction is based on a one-sided understanding of systems biology as a science that is only interested in functional, not evolutionary, aspects of biological processes. Instead, we propose a research program for an evolutionary systems biology, which is based on local exploration of the configuration space in evolving developmental systems. We call this approach-which is based on reverse engineering, simulation, and mathematical analysis-the natural history of configuration space. We discuss a number of illustrative examples that demonstrate the past success of local exploration, as opposed to global mapping, in different biological contexts. We argue that this pragmatic mode of inquiry can be extended and applied to the mathematical analysis of the developmental repertoire and evolutionary potential of evolving developmental mechanisms and that evolutionary systems biology so conceived provides a pragmatic epistemological framework for the EvoDevo synthesis.

  20. Model-independent cosmological constraints from growth and expansion

    Science.gov (United States)

    L'Huillier, Benjamin; Shafieloo, Arman; Kim, Hyungjin

    2018-05-01

    Reconstructing the expansion history of the Universe from Type Ia supernovae data, we fit the growth rate measurements and put model-independent constraints on some key cosmological parameters, namely, Ωm, γ, and σ8. The constraints are consistent with those from the concordance model within the framework of general relativity, but the current quality of the data is not sufficient to rule out modified gravity models. Adding the condition that dark energy density should be positive at all redshifts, independently of its equation of state, further constrains the parameters and interestingly supports the concordance model.

  1. Data assimilation with inequality constraints

    Science.gov (United States)

    Thacker, W. C.

    If values of variables in a numerical model are limited to specified ranges, these restrictions should be enforced when data are assimilated. The simplest option is to assimilate without regard for constraints and then to correct any violations without worrying about additional corrections implied by correlated errors. This paper addresses the incorporation of inequality constraints into the standard variational framework of optimal interpolation with emphasis on our limited knowledge of the underlying probability distributions. Simple examples involving only two or three variables are used to illustrate graphically how active constraints can be treated as error-free data when background errors obey a truncated multi-normal distribution. Using Lagrange multipliers, the formalism is expanded to encompass the active constraints. Two algorithms are presented, both relying on a solution ignoring the inequality constraints to discover violations to be enforced. While explicitly enforcing a subset can, via correlations, correct the others, pragmatism based on our poor knowledge of the underlying probability distributions suggests the expedient of enforcing them all explicitly to avoid the computationally expensive task of determining the minimum active set. If additional violations are encountered with these solutions, the process can be repeated. Simple examples are used to illustrate the algorithms and to examine the nature of the corrections implied by correlated errors.

  2. A Practical Software Architecture for Virtual Universities

    Science.gov (United States)

    Xiang, Peifeng; Shi, Yuanchun; Qin, Weijun

    2006-01-01

    This article introduces a practical software architecture called CUBES, which focuses on system integration and evolvement for online virtual universities. The key of CUBES is a supporting platform that helps to integrate and evolve heterogeneous educational applications developed by different organizations. Both standardized educational…

  3. The Emergent Universe scheme and tunneling

    Energy Technology Data Exchange (ETDEWEB)

    Labraña, Pedro [Departamento de Física, Universidad del Bío-Bío, Avenida Collao 1202, Casilla 5-C, Concepción, Chile and Departament d' Estructura i Constituents de la Matèria and Institut de Ciències del Cosmos, Universitat (Spain)

    2014-07-23

    We present an alternative scheme for an Emergent Universe scenario, developed previously in Phys. Rev. D 86, 083524 (2012), where the universe is initially in a static state supported by a scalar field located in a false vacuum. The universe begins to evolve when, by quantum tunneling, the scalar field decays into a state of true vacuum. The Emergent Universe models are interesting since they provide specific examples of non-singular inflationary universes.

  4. Invariant Set Theory: Violating Measurement Independence without Fine Tuning, Conspiracy, Constraints on Free Will or Retrocausality

    Directory of Open Access Journals (Sweden)

    Tim Palmer

    2015-11-01

    Full Text Available Invariant Set (IS theory is a locally causal ontic theory of physics based on the Cosmological Invariant Set postulate that the universe U can be considered a deterministic dynamical system evolving precisely on a (suitably constructed fractal dynamically invariant set in U's state space. IS theory violates the Bell inequalities by violating Measurement Independence. Despite this, IS theory is not fine tuned, is not conspiratorial, does not constrain experimenter free will and does not invoke retrocausality. The reasons behind these claims are discussed in this paper. These arise from properties not found in conventional ontic models: the invariant set has zero measure in its Euclidean embedding space, has Cantor Set structure homeomorphic to the p-adic integers (p>>0 and is non-computable. In particular, it is shown that the p-adic metric encapulates the physics of the Cosmological Invariant Set postulate, and provides the technical means to demonstrate no fine tuning or conspiracy. Quantum theory can be viewed as the singular limit of IS theory when when p is set equal to infinity. Since it is based around a top-down constraint from cosmology, IS theory suggests that gravitational and quantum physics will be unified by a gravitational theory of the quantum, rather than a quantum theory of gravity. Some implications arising from such a perspective are discussed.

  5. Constraint programming and decision making

    CERN Document Server

    Kreinovich, Vladik

    2014-01-01

    In many application areas, it is necessary to make effective decisions under constraints. Several area-specific techniques are known for such decision problems; however, because these techniques are area-specific, it is not easy to apply each technique to other applications areas. Cross-fertilization between different application areas is one of the main objectives of the annual International Workshops on Constraint Programming and Decision Making. Those workshops, held in the US (El Paso, Texas), in Europe (Lyon, France), and in Asia (Novosibirsk, Russia), from 2008 to 2012, have attracted researchers and practitioners from all over the world. This volume presents extended versions of selected papers from those workshops. These papers deal with all stages of decision making under constraints: (1) formulating the problem of multi-criteria decision making in precise terms, (2) determining when the corresponding decision problem is algorithmically solvable; (3) finding the corresponding algorithms, and making...

  6. Sulphur-bearing Compounds Detected by MSL SAM Evolved Gas Analysis of Materials from Yellowknife Bay, Gale Crater, Mars

    Science.gov (United States)

    McAdam, A. C.; Franz, H. B.; Archer, P. D. Jr.; Sutter, B.; Eigenbrode, J. L.; Freissinet, C.; Atreya, S. K.; Bish, D. L.; Blake, D. F.; Brunner, A.; hide

    2014-01-01

    The Sample Analysis at Mars (SAM) and Chemistry and Mineralogy (CheMin) instruments on the Mars Science Laboratory (MSL) analysed several subsamples of sample fines (bearing phases present below the CheMin detection limit or difficult to characterize with XRD (e.g., X-ray amorphous phases). Here, we focus on potential constraints on phases that evolved SO2, H2S, OCS, and CS2 during thermal analysis.

  7. Evaluation of uranium resources. Problems and constraints

    International Nuclear Information System (INIS)

    Williams, R.M.

    1979-01-01

    Growing awareness that the era of cheap energy is over has led to current efforts by governments and international organizations to examine the question of the adequacy of energy resources on a global scale. Despite the relative success of the NEA and the IAEA efforts in the study of world uranium supply, there is a need for such studies to become still more comprehensive and broader in scope. A basic problem exists with respect to the lack of a universally accepted set of resource terms by which to classify resource estimates once they are made. Often voids exist in international assessments because of insufficient data with respect to known resources and occasionally because of a lack of expertise to make the required estimates. With respect to the assessment of undiscovered uranium resources, major constraints are the relatively embryonic state of methodology for assessment of undiscovered resources and the fact that the inventory of basic geology, geochemical, and geophysical data is either incomplete or non-existent in many parts of the world. Finally, once resource estimates are made, there is often an unclear understanding about when and at what rate the resources can be made available. Hopefully, current efforts will lead to a solution to some of the principal problems and constraints which may be impeding progress toward an expansion and improvement of world uranium resource assessments. (author)

  8. Experimental constraint on quark electric dipole moments

    Science.gov (United States)

    Liu, Tianbo; Zhao, Zhiwen; Gao, Haiyan

    2018-04-01

    The electric dipole moments (EDMs) of nucleons are sensitive probes of additional C P violation sources beyond the standard model to account for the baryon number asymmetry of the universe. As a fundamental quantity of the nucleon structure, tensor charge is also a bridge that relates nucleon EDMs to quark EDMs. With a combination of nucleon EDM measurements and tensor charge extractions, we investigate the experimental constraint on quark EDMs, and its sensitivity to C P violation sources from new physics beyond the electroweak scale. We obtain the current limits on quark EDMs as 1.27 ×10-24 e .cm for the up quark and 1.17 ×10-24 e .cm for the down quark at the scale of 4 GeV2 . We also study the impact of future nucleon EDM and tensor charge measurements, and show that upcoming new experiments will improve the constraint on quark EDMs by about 3 orders of magnitude leading to a much more sensitive probe of new physics models.

  9. Evolvability as a Quality Attribute of Software Architectures

    NARCIS (Netherlands)

    Ciraci, S.; van den Broek, P.M.; Duchien, Laurence; D'Hondt, Maja; Mens, Tom

    We review the definition of evolvability as it appears on the literature. In particular, the concept of software evolvability is compared with other system quality attributes, such as adaptability, maintainability and modifiability.

  10. Cosmological constraints on neutrinos with Planck data

    International Nuclear Information System (INIS)

    Spinelli, M.

    2015-01-01

    Neutrinos take part in the dance of the evolving Universe influencing its history from leptogenesis, to Big Bang nucleosynthesis, until late time structure formation. This makes cosmology, and in particular one of its primary observables the Cosmic Microwave Background (CMB), an unusual but valuable tool for testing Neutrino Physics. The best measurement to date of full-sky CMB anisotropies comes from the Planck satellite launched in 2009 by the European Space Agency (ESA) and successful follower of COBE and WMAP. Testing Planck data against precise theoretical predictions allow us to shed light on various interesting open questions such as the value of the absolute scale of neutrino masses or their energy density. We revise here the results concerning neutrinos obtained by the Planck Collaboration in the 2013 data release

  11. Cosmological constraints on neutrinos with Planck data

    Energy Technology Data Exchange (ETDEWEB)

    Spinelli, M. [Laboratoire de l’Accélérateur Linéaire, Bat.200, 91400 Orsay (France)

    2015-07-15

    Neutrinos take part in the dance of the evolving Universe influencing its history from leptogenesis, to Big Bang nucleosynthesis, until late time structure formation. This makes cosmology, and in particular one of its primary observables the Cosmic Microwave Background (CMB), an unusual but valuable tool for testing Neutrino Physics. The best measurement to date of full-sky CMB anisotropies comes from the Planck satellite launched in 2009 by the European Space Agency (ESA) and successful follower of COBE and WMAP. Testing Planck data against precise theoretical predictions allow us to shed light on various interesting open questions such as the value of the absolute scale of neutrino masses or their energy density. We revise here the results concerning neutrinos obtained by the Planck Collaboration in the 2013 data release.

  12. Cosmological constraints on neutrinos with Planck data

    Science.gov (United States)

    Spinelli, M.

    2015-07-01

    Neutrinos take part in the dance of the evolving Universe influencing its history from leptogenesis, to Big Bang nucleosynthesis, until late time structure formation. This makes cosmology, and in particular one of its primary observables the Cosmic Microwave Background (CMB), an unusual but valuable tool for testing Neutrino Physics. The best measurement to date of full-sky CMB anisotropies comes from the Planck satellite launched in 2009 by the European Space Agency (ESA) and successful follower of COBE and WMAP. Testing Planck data against precise theoretical predictions allow us to shed light on various interesting open questions such as the value of the absolute scale of neutrino masses or their energy density. We revise here the results concerning neutrinos obtained by the Planck Collaboration in the 2013 data release.

  13. Evolving colon injury management: a review.

    Science.gov (United States)

    Greer, Lauren T; Gillern, Suzanne M; Vertrees, Amy E

    2013-02-01

    The colon is the second most commonly injured intra-abdominal organ in penetrating trauma. Management of traumatic colon injuries has evolved significantly over the past 200 years. Traumatic colon injuries can have a wide spectrum of severity, presentation, and management options. There is strong evidence that most non-destructive colon injuries can be successfully managed with primary repair or primary anastomosis. The management of destructive colon injuries remains controversial with most favoring resection with primary anastomosis and others favor colonic diversion in specific circumstances. The historical management of traumatic colon injuries, common mechanisms of injury, demographics, presentation, assessment, diagnosis, management, and complications of traumatic colon injuries both in civilian and military practice are reviewed. The damage control revolution has added another layer of complexity to management with continued controversy.

  14. Pulmonary Sporotrichosis: An Evolving Clinical Paradigm.

    Science.gov (United States)

    Aung, Ar K; Spelman, Denis W; Thompson, Philip J

    2015-10-01

    In recent decades, sporotrichosis, caused by thermally dimorphic fungi Sporothrix schenckii complex, has become an emerging infection in many parts of the world. Pulmonary infection with S. schenckii still remains relatively uncommon, possibly due to underrecognition. Pulmonary sporotrichosis presents with distinct clinical and radiological patterns in both immunocompetent and immunocompromised hosts and can often result in significant morbidity and mortality despite treatment. Current understanding regarding S. schenckii biology, epidemiology, immunopathology, clinical diagnostics, and treatment options has been evolving in the recent years with increased availability of molecular sequencing techniques. However, this changing knowledge has not yet been fully translated into a better understanding of the clinical aspects of pulmonary sporotrichosis, as such current management guidelines remain unsupported by high-level clinical evidence. This article examines recent advances in the knowledge of sporotrichosis and its application to the difficult challenges of managing pulmonary sporotrichosis. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  15. Resiliently evolving supply-demand networks

    Science.gov (United States)

    Rubido, Nicolás; Grebogi, Celso; Baptista, Murilo S.

    2014-01-01

    The ability to design a transport network such that commodities are brought from suppliers to consumers in a steady, optimal, and stable way is of great importance for distribution systems nowadays. In this work, by using the circuit laws of Kirchhoff and Ohm, we provide the exact capacities of the edges that an optimal supply-demand network should have to operate stably under perturbations, i.e., without overloading. The perturbations we consider are the evolution of the connecting topology, the decentralization of hub sources or sinks, and the intermittence of supplier and consumer characteristics. We analyze these conditions and the impact of our results, both on the current United Kingdom power-grid structure and on numerically generated evolving archetypal network topologies.

  16. Evolving spiking networks with variable resistive memories.

    Science.gov (United States)

    Howard, Gerard; Bull, Larry; de Lacy Costello, Ben; Gale, Ella; Adamatzky, Andrew

    2014-01-01

    Neuromorphic computing is a brainlike information processing paradigm that requires adaptive learning mechanisms. A spiking neuro-evolutionary system is used for this purpose; plastic resistive memories are implemented as synapses in spiking neural networks. The evolutionary design process exploits parameter self-adaptation and allows the topology and synaptic weights to be evolved for each network in an autonomous manner. Variable resistive memories are the focus of this research; each synapse has its own conductance profile which modifies the plastic behaviour of the device and may be altered during evolution. These variable resistive networks are evaluated on a noisy robotic dynamic-reward scenario against two static resistive memories and a system containing standard connections only. The results indicate that the extra behavioural degrees of freedom available to the networks incorporating variable resistive memories enable them to outperform the comparative synapse types.

  17. Life cycle planning: An evolving concept

    International Nuclear Information System (INIS)

    Moore, P.J.R.; Gorman, I.G.

    1994-01-01

    Life-cycle planning is an evolving concept in the management of oil and gas projects. BHP Petroleum now interprets this idea to include all development planning from discovery and field appraisal to final abandonment and includes safety, environmental, technical, plant, regulatory, and staffing issues. This article describes in the context of the Timor Sea, how despite initial successes and continuing facilities upgrades, BHPP came to perceive that current operations could be the victim of early development successes, particularly in the areas of corrosion and maintenance. The search for analogies elsewhere lead to the UK North Sea, including the experiences of Britoil and BP, both of which performed detailed Life of Field studies in the later eighties. These materials have been used to construct a format and content for total Life-cycle plans in general and the social changes required to ensure their successful application in Timor Sea operations and deployment throughout Australia

  18. Argentina and Brazil: an evolving nuclear relationship

    International Nuclear Information System (INIS)

    Redick, J.R.

    1990-01-01

    Argentina and Brazil have Latin America's most advanced nuclear research and power programs. Both nations reject the Non-Proliferation Treaty (NPT), and have not formally embraced the Tlatelolco Treaty creating a regional nuclear-weapon-free zone. Disturbing ambiguities persist regarding certain indigenous nuclear facilities and growing nuclear submarine and missile capabilities. For these, and other reasons, the two nations are widely considered potential nuclear weapon states. However both nations have been active supporters of the International Atomic Energy Agency (IAEA) and have, in recent years, assumed a generally responsible position in regard to their own nuclear export activities (requiring IAEA safeguards). Most important, however, has been the advent of bilateral nuclear cooperation. This paper considers the evolving nuclear relationship in the context of recent and dramatic political change in Argentina and Brazil. It discusses current political and nuclear developments and the prospects for maintaining and expanding present bilateral cooperation into an effective non-proliferation arrangement. (author)

  19. Data Integration against Multiple Evolving Autonomous Schemata

    CERN Document Server

    Koch, Christoph

    Research in the area of data integration has resulted in approaches such as federated and multidatabases, mediation, data warehousing, global information systems, and the model management/schema matching approach. Architecturally, approaches can be categorized into those that integrate against a single global schema and those that do not, while on the level of inter-schema constraints, most work can be classied either as so-called global-as-view or as local-as-view integration. These approaches dier widely in their strengths and weaknesses. Federated databases have been found applicable in environments in which several autonomous information systems coexist { each with their individual schemata { and need to share data. However, this approach does not provide sucient support for dealing with change of schemata and requirements. Other approaches to data integration which are centered around a single \\global" integration schema, on the other hand, cannot handle design autonomy of information systems. Under evol...

  20. The genotype-phenotype map of an evolving digital organism

    OpenAIRE

    Fortuna, Miguel A.; Zaman, Luis; Ofria, Charles; Wagner, Andreas

    2017-01-01

    To understand how evolving systems bring forth novel and useful phenotypes, it is essential to understand the relationship between genotypic and phenotypic change. Artificial evolving systems can help us understand whether the genotype-phenotype maps of natural evolving systems are highly unusual, and it may help create evolvable artificial systems. Here we characterize the genotype-phenotype map of digital organisms in Avida, a platform for digital evolution. We consider digital organisms fr...

  1. Combining experimental and cosmological constraints on heavy neutrinos

    Directory of Open Access Journals (Sweden)

    Marco Drewes

    2017-08-01

    Full Text Available We study experimental and cosmological constraints on the extension of the Standard Model by three right handed neutrinos with masses between those of the pion and W boson. We combine for the first time direct, indirect and cosmological constraints in this mass range. This includes experimental constraints from neutrino oscillation data, neutrinoless double β decay, electroweak precision data, lepton universality, searches for rare lepton decays, tests of CKM unitarity and past direct searches at colliders or fixed target experiments. On the cosmological side, big bang nucleosynthesis has the most pronounced impact. Our results can be used to evaluate the discovery potential of searches for heavy neutrinos at LHCb, BELLE II, SHiP, ATLAS, CMS or a future lepton collider.

  2. Fluid flow and sediment transport in evolving sedimentary basins

    Science.gov (United States)

    Swenson, John Bradley

    This thesis consists of three studies that focus on groundwater flow and sediment transport in evolving sedimentary basins. The first study considers the subsurface hydrodynamic response to basin-scale transgression and regression and its implications for stratiform ore genesis. I demonstrate that the transgressive sequence focuses marginward-directed, compaction-driven discharge within a basal aquifer during progradation and deposition of the overlying regressive sequence, isolates the basal aquifer from overlying flow systems, and serves as a chemical sink for metal-bearing brines. In the second study, I develop a new theory for the shoreline response to subsidence, sediment supply, and sea level. In this theory, sediment transport in a fluvio-deltaic basin is formally equivalent to heat transfer in a two-phase (liquid and isothermal solid) system: the fluvial system is analogous to a conduction-dominated liquid phase, the shoreline is the melting front, and the water depth at the delta toe is equivalent to the latent heat of fusion. A natural consequence of this theory is that sediment-starved basins do not possess an equilibrium state. In contrast to existing theories, I do not observe either strong phase shifting or attenuation of the shoreline response to low-frequency eustatic forcing; rather, shoreline tracks sea level over a spectrum of forcing frequencies, and its response to low-frequency forcing is amplified relative to the high-frequency response. For the third study, I use a set of dimensionless numbers from the previous study as a mathematical framework for providing a unified treatment of existing stratigraphic theories. In the limit of low-amplitude eustatic forcing, my study suggests that strong phase shifting between shoreline and sea level is a consequence of specifying the sedimentation rate at the shoreline; basins free of this constraint do not develop strong phase shifts.

  3. Constraint elimination in dynamical systems

    Science.gov (United States)

    Singh, R. P.; Likins, P. W.

    1989-01-01

    Large space structures (LSSs) and other dynamical systems of current interest are often extremely complex assemblies of rigid and flexible bodies subjected to kinematical constraints. A formulation is presented for the governing equations of constrained multibody systems via the application of singular value decomposition (SVD). The resulting equations of motion are shown to be of minimum dimension.

  4. Constraint Programming versus Mathematical Programming

    DEFF Research Database (Denmark)

    Hansen, Jesper

    2003-01-01

    Constraint Logic Programming (CLP) is a relatively new technique from the 80's with origins in Computer Science and Artificial Intelligence. Lately, much research have been focused on ways of using CLP within the paradigm of Operations Research (OR) and vice versa. The purpose of this paper...

  5. Sterile neutrino constraints from cosmology

    DEFF Research Database (Denmark)

    Hamann, Jan; Hannestad, Steen; Raffelt, Georg G.

    2012-01-01

    The presence of light particles beyond the standard model's three neutrino species can profoundly impact the physics of decoupling and primordial nucleosynthesis. I review the observational signatures of extra light species, present constraints from recent data, and discuss the implications of po...... of possible sterile neutrinos with O(eV)-masses for cosmology....

  6. Intertemporal consumption and credit constraints

    DEFF Research Database (Denmark)

    Leth-Petersen, Søren

    2010-01-01

    There is continuing controversy over the importance of credit constraints. This paper investigates whether total household expenditure and debt is affected by an exogenous increase in access to credit provided by a credit market reform that enabled Danish house owners to use housing equity...

  7. Financial Constraints: Explaining Your Position.

    Science.gov (United States)

    Cargill, Jennifer

    1988-01-01

    Discusses the importance of educating library patrons about the library's finances and the impact of budget constraints and the escalating cost of serials on materials acquisition. Steps that can be taken in educating patrons by interpreting and publicizing financial information are suggested. (MES)

  8. Is our Universe typical?

    International Nuclear Information System (INIS)

    Gurzadyan, V.G.

    1988-01-01

    The problem of typicalness of the Universe - as a dynamical system possessing both regular and chaotic regions of positive measure of phase space, is raised and discussed. Two dynamical systems are considered: 1) The observed Universe as a hierarchy of systems of N graviting bodies; 2) (3+1)-manifold with matter evolving to Wheeler-DeWitt equation in superspace with Hawking boundary condition of compact metrics. It is shown that the observed Universe is typical. There is no unambiguous answer for the second system yet. If it is typical too then the same present state of the Universe could have been originated from an infinite number of different initial conditions the restoration of which is practically impossible at present. 35 refs.; 2 refs

  9. The accidental universe

    International Nuclear Information System (INIS)

    Davies, P.C.W.

    1982-01-01

    Is our universe an accident of nature. The mysterious coincidences underlying the structure and properties of the universe that we inhabit are examined. This is the first book for the non-specialist reader to present in depth the provocative hypothesis that the structure of the physical world is exceedingly contrived in its appearance. A survey is presented of the range of apparently miraculous accidents of nature that have enabled the universe to evolve its familiar structures: atoms, stars, galaxies, and life itself. This book concludes with an investigation of the so-called 'anthropic principle' which postulates that 'miraculous coincidences' are inevitable in any universe containing conscious observers. This thesis of a cosmic biological selection effect will both reassure and enrage readers, the very existence of whom may be related to fine tuning in the laws of physics. (author)

  10. Synonymous codon bias and functional constraint on GC3-related DNA backbone dynamics in the prokaryotic nucleoid.

    Science.gov (United States)

    Babbitt, Gregory A; Alawad, Mohammed A; Schulze, Katharina V; Hudson, André O

    2014-01-01

    While mRNA stability has been demonstrated to control rates of translation, generating both global and local synonymous codon biases in many unicellular organisms, this explanation cannot adequately explain why codon bias strongly tracks neighboring intergene GC content; suggesting that structural dynamics of DNA might also influence codon choice. Because minor groove width is highly governed by 3-base periodicity in GC, the existence of triplet-based codons might imply a functional role for the optimization of local DNA molecular dynamics via GC content at synonymous sites (≈GC3). We confirm a strong association between GC3-related intrinsic DNA flexibility and codon bias across 24 different prokaryotic multiple whole-genome alignments. We develop a novel test of natural selection targeting synonymous sites and demonstrate that GC3-related DNA backbone dynamics have been subject to moderate selective pressure, perhaps contributing to our observation that many genes possess extreme DNA backbone dynamics for their given protein space. This dual function of codons may impose universal functional constraints affecting the evolution of synonymous and non-synonymous sites. We propose that synonymous sites may have evolved as an 'accessory' during an early expansion of a primordial genetic code, allowing for multiplexed protein coding and structural dynamic information within the same molecular context. © The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.

  11. Linear-constraint wavefront control for exoplanet coronagraphic imaging systems

    Science.gov (United States)

    Sun, He; Eldorado Riggs, A. J.; Kasdin, N. Jeremy; Vanderbei, Robert J.; Groff, Tyler Dean

    2017-01-01

    A coronagraph is a leading technology for achieving high-contrast imaging of exoplanets in a space telescope. It uses a system of several masks to modify the diffraction and achieve extremely high contrast in the image plane around target stars. However, coronagraphic imaging systems are very sensitive to optical aberrations, so wavefront correction using deformable mirrors (DMs) is necessary to avoid contrast degradation in the image plane. Electric field conjugation (EFC) and Stroke minimization (SM) are two primary high-contrast wavefront controllers explored in the past decade. EFC minimizes the average contrast in the search areas while regularizing the strength of the control inputs. Stroke minimization calculates the minimum DM commands under the constraint that a target average contrast is achieved. Recently in the High Contrast Imaging Lab at Princeton University (HCIL), a new linear-constraint wavefront controller based on stroke minimization was developed and demonstrated using numerical simulation. Instead of only constraining the average contrast over the entire search area, the new controller constrains the electric field of each single pixel using linear programming, which could led to significant increases in speed of the wavefront correction and also create more uniform dark holes. As a follow-up of this work, another linear-constraint controller modified from EFC is demonstrated theoretically and numerically and the lab verification of the linear-constraint controllers is reported. Based on the simulation and lab results, the pros and cons of linear-constraint controllers are carefully compared with EFC and stroke minimization.

  12. The evolving energy budget of accretionary wedges

    Science.gov (United States)

    McBeck, Jessica; Cooke, Michele; Maillot, Bertrand; Souloumiac, Pauline

    2017-04-01

    The energy budget of evolving accretionary systems reveals how deformational processes partition energy as faults slip, topography uplifts, and layer-parallel shortening produces distributed off-fault deformation. The energy budget provides a quantitative framework for evaluating the energetic contribution or consumption of diverse deformation mechanisms. We investigate energy partitioning in evolving accretionary prisms by synthesizing data from physical sand accretion experiments and numerical accretion simulations. We incorporate incremental strain fields and cumulative force measurements from two suites of experiments to design numerical simulations that represent accretionary wedges with stronger and weaker detachment faults. One suite of the physical experiments includes a basal glass bead layer and the other does not. Two physical experiments within each suite implement different boundary conditions (stable base versus moving base configuration). Synthesizing observations from the differing base configurations reduces the influence of sidewall friction because the force vector produced by sidewall friction points in opposite directions depending on whether the base is fixed or moving. With the numerical simulations, we calculate the energy budget at two stages of accretion: at the maximum force preceding the development of the first thrust pair, and at the minimum force following the development of the pair. To identify the appropriate combination of material and fault properties to apply in the simulations, we systematically vary the Young's modulus and the fault static and dynamic friction coefficients in numerical accretion simulations, and identify the set of parameters that minimizes the misfit between the normal force measured on the physical backwall and the numerically simulated force. Following this derivation of the appropriate material and fault properties, we calculate the components of the work budget in the numerical simulations and in the

  13. On the Critical Role of Divergent Selection in Evolvability

    Directory of Open Access Journals (Sweden)

    Joel Lehman

    2016-08-01

    Full Text Available An ambitious goal in evolutionary robotics is to evolve increasingly complex robotic behaviors with minimal human design effort. Reaching this goal requires evolutionary algorithms that can unlock from genetic encodings their latent potential for evolvability. One issue clouding this goal is conceptual confusion about evolvability, which often obscures the aspects of evolvability that are important or desirable. The danger from such confusion is that it may establish unrealistic goals for evolvability that prove unproductive in practice. An important issue separate from conceptual confusion is the common misalignment between selection and evolvability in evolutionary robotics. While more expressive encodings can represent higher-level adaptations (e.g. sexual reproduction or developmental systems that increase long-term evolutionary potential (i.e. evolvability, realizing such potential requires gradients of fitness and evolvability to align. In other words, selection is often a critical factor limiting increasing evolvability. Thus, drawing from a series of recent papers, this article seeks to both (1 clarify and focus the ways in which the term evolvability is used within artificial evolution, and (2 argue for the importance of one type of selection, i.e. divergent selection, for enabling evolvability. The main argument is that there is a fundamental connection between divergent selection and evolvability (on both the individual and population level that does not hold for typical goal-oriented selection. The conclusion is that selection pressure plays a critical role in realizing the potential for evolvability, and that divergent selection in particular provides a principled mechanism for encouraging evolvability in artificial evolution.

  14. Approximating centrality in evolving graphs: toward sublinearity

    Science.gov (United States)

    Priest, Benjamin W.; Cybenko, George

    2017-05-01

    The identification of important nodes is a ubiquitous problem in the analysis of social networks. Centrality indices (such as degree centrality, closeness centrality, betweenness centrality, PageRank, and others) are used across many domains to accomplish this task. However, the computation of such indices is expensive on large graphs. Moreover, evolving graphs are becoming increasingly important in many applications. It is therefore desirable to develop on-line algorithms that can approximate centrality measures using memory sublinear in the size of the graph. We discuss the challenges facing the semi-streaming computation of many centrality indices. In particular, we apply recent advances in the streaming and sketching literature to provide a preliminary streaming approximation algorithm for degree centrality utilizing CountSketch and a multi-pass semi-streaming approximation algorithm for closeness centrality leveraging a spanner obtained through iteratively sketching the vertex-edge adjacency matrix. We also discuss possible ways forward for approximating betweenness centrality, as well as spectral measures of centrality. We provide a preliminary result using sketched low-rank approximations to approximate the output of the HITS algorithm.

  15. An Evolving Worldview: Making Open Source Easy

    Science.gov (United States)

    Rice, Z.

    2017-12-01

    NASA Worldview is an interactive interface for browsing full-resolution, global satellite imagery. Worldview supports an open data policy so that academia, private industries and the general public can use NASA's satellite data to address Earth science related issues. Worldview was open sourced in 2014. By shifting to an open source approach, the Worldview application has evolved to better serve end-users. Project developers are able to have discussions with end-users and community developers to understand issues and develop new features. Community developers are able to track upcoming features, collaborate on them and make their own contributions. Developers who discover issues are able to address those issues and submit a fix. This reduces the time it takes for a project developer to reproduce an issue or develop a new feature. Getting new developers to contribute to the project has been one of the most important and difficult aspects of open sourcing Worldview. After witnessing potential outside contributors struggle, a focus has been made on making the installation of Worldview simple to reduce the initial learning curve and make contributing code easy. One way we have addressed this is through a simplified setup process. Our setup documentation includes a set of prerequisites and a set of straightforward commands to clone, configure, install and run. This presentation will emphasize our focus to simplify and standardize Worldview's open source code so that more people are able to contribute. The more people who contribute, the better the application will become over time.

  16. Extreme insular dwarfism evolved in a mammoth.

    Science.gov (United States)

    Herridge, Victoria L; Lister, Adrian M

    2012-08-22

    The insular dwarfism seen in Pleistocene elephants has come to epitomize the island rule; yet our understanding of this phenomenon is hampered by poor taxonomy. For Mediterranean dwarf elephants, where the most extreme cases of insular dwarfism are observed, a key systematic question remains unresolved: are all taxa phyletic dwarfs of a single mainland species Palaeoloxodon antiquus (straight-tusked elephant), or are some referable to Mammuthus (mammoths)? Ancient DNA and geochronological evidence have been used to support a Mammuthus origin for the Cretan 'Palaeoloxodon' creticus, but these studies have been shown to be flawed. On the basis of existing collections and recent field discoveries, we present new, morphological evidence for the taxonomic status of 'P'. creticus, and show that it is indeed a mammoth, most probably derived from Early Pleistocene Mammuthus meridionalis or possibly Late Pliocene Mammuthus rumanus. We also show that Mammuthus creticus is smaller than other known insular dwarf mammoths, and is similar in size to the smallest dwarf Palaeoloxodon species from Sicily and Malta, making it the smallest mammoth species known to have existed. These findings indicate that extreme insular dwarfism has evolved to a similar degree independently in two elephant lineages.

  17. How does cognition evolve? Phylogenetic comparative psychology.

    Science.gov (United States)

    MacLean, Evan L; Matthews, Luke J; Hare, Brian A; Nunn, Charles L; Anderson, Rindy C; Aureli, Filippo; Brannon, Elizabeth M; Call, Josep; Drea, Christine M; Emery, Nathan J; Haun, Daniel B M; Herrmann, Esther; Jacobs, Lucia F; Platt, Michael L; Rosati, Alexandra G; Sandel, Aaron A; Schroepfer, Kara K; Seed, Amanda M; Tan, Jingzhi; van Schaik, Carel P; Wobber, Victoria

    2012-03-01

    Now more than ever animal studies have the potential to test hypotheses regarding how cognition evolves. Comparative psychologists have developed new techniques to probe the cognitive mechanisms underlying animal behavior, and they have become increasingly skillful at adapting methodologies to test multiple species. Meanwhile, evolutionary biologists have generated quantitative approaches to investigate the phylogenetic distribution and function of phenotypic traits, including cognition. In particular, phylogenetic methods can quantitatively (1) test whether specific cognitive abilities are correlated with life history (e.g., lifespan), morphology (e.g., brain size), or socio-ecological variables (e.g., social system), (2) measure how strongly phylogenetic relatedness predicts the distribution of cognitive skills across species, and (3) estimate the ancestral state of a given cognitive trait using measures of cognitive performance from extant species. Phylogenetic methods can also be used to guide the selection of species comparisons that offer the strongest tests of a priori predictions of cognitive evolutionary hypotheses (i.e., phylogenetic targeting). Here, we explain how an integration of comparative psychology and evolutionary biology will answer a host of questions regarding the phylogenetic distribution and history of cognitive traits, as well as the evolutionary processes that drove their evolution.

  18. An evolving network model with modular growth

    International Nuclear Information System (INIS)

    Zou Zhi-Yun; Liu Peng; Lei Li; Gao Jian-Zhi

    2012-01-01

    In this paper, we propose an evolving network model growing fast in units of module, according to the analysis of the evolution characteristics in real complex networks. Each module is a small-world network containing several interconnected nodes and the nodes between the modules are linked by preferential attachment on degree of nodes. We study the modularity measure of the proposed model, which can be adjusted by changing the ratio of the number of inner-module edges and the number of inter-module edges. In view of the mean-field theory, we develop an analytical function of the degree distribution, which is verified by a numerical example and indicates that the degree distribution shows characteristics of the small-world network and the scale-free network distinctly at different segments. The clustering coefficient and the average path length of the network are simulated numerically, indicating that the network shows the small-world property and is affected little by the randomness of the new module. (interdisciplinary physics and related areas of science and technology)

  19. How does cognition evolve? Phylogenetic comparative psychology

    Science.gov (United States)

    Matthews, Luke J.; Hare, Brian A.; Nunn, Charles L.; Anderson, Rindy C.; Aureli, Filippo; Brannon, Elizabeth M.; Call, Josep; Drea, Christine M.; Emery, Nathan J.; Haun, Daniel B. M.; Herrmann, Esther; Jacobs, Lucia F.; Platt, Michael L.; Rosati, Alexandra G.; Sandel, Aaron A.; Schroepfer, Kara K.; Seed, Amanda M.; Tan, Jingzhi; van Schaik, Carel P.; Wobber, Victoria

    2014-01-01

    Now more than ever animal studies have the potential to test hypotheses regarding how cognition evolves. Comparative psychologists have developed new techniques to probe the cognitive mechanisms underlying animal behavior, and they have become increasingly skillful at adapting methodologies to test multiple species. Meanwhile, evolutionary biologists have generated quantitative approaches to investigate the phylogenetic distribution and function of phenotypic traits, including cognition. In particular, phylogenetic methods can quantitatively (1) test whether specific cognitive abilities are correlated with life history (e.g., lifespan), morphology (e.g., brain size), or socio-ecological variables (e.g., social system), (2) measure how strongly phylogenetic relatedness predicts the distribution of cognitive skills across species, and (3) estimate the ancestral state of a given cognitive trait using measures of cognitive performance from extant species. Phylogenetic methods can also be used to guide the selection of species comparisons that offer the strongest tests of a priori predictions of cognitive evolutionary hypotheses (i.e., phylogenetic targeting). Here, we explain how an integration of comparative psychology and evolutionary biology will answer a host of questions regarding the phylogenetic distribution and history of cognitive traits, as well as the evolutionary processes that drove their evolution. PMID:21927850

  20. A local-world evolving hypernetwork model

    International Nuclear Information System (INIS)

    Yang Guang-Yong; Liu Jian-Guo

    2014-01-01

    Complex hypernetworks are ubiquitous in the real system. It is very important to investigate the evolution mechanisms. In this paper, we present a local-world evolving hypernetwork model by taking into account the hyperedge growth and local-world hyperedge preferential attachment mechanisms. At each time step, a newly added hyperedge encircles a new coming node and a number of nodes from a randomly selected local world. The number of the selected nodes from the local world obeys the uniform distribution and its mean value is m. The analytical and simulation results show that the hyperdegree approximately obeys the power-law form and the exponent of hyperdegree distribution is γ = 2 + 1/m. Furthermore, we numerically investigate the node degree, hyperedge degree, clustering coefficient, as well as the average distance, and find that the hypernetwork model shares the scale-free and small-world properties, which shed some light for deeply understanding the evolution mechanism of the real systems. (interdisciplinary physics and related areas of science and technology)

  1. Evolving autonomous learning in cognitive networks.

    Science.gov (United States)

    Sheneman, Leigh; Hintze, Arend

    2017-12-01

    There are two common approaches for optimizing the performance of a machine: genetic algorithms and machine learning. A genetic algorithm is applied over many generations whereas machine learning works by applying feedback until the system meets a performance threshold. These methods have been previously combined, particularly in artificial neural networks using an external objective feedback mechanism. We adapt this approach to Markov Brains, which are evolvable networks of probabilistic and deterministic logic gates. Prior to this work MB could only adapt from one generation to the other, so we introduce feedback gates which augment their ability to learn during their lifetime. We show that Markov Brains can incorporate these feedback gates in such a way that they do not rely on an external objective feedback signal, but instead can generate internal feedback that is then used to learn. This results in a more biologically accurate model of the evolution of learning, which will enable us to study the interplay between evolution and learning and could be another step towards autonomously learning machines.

  2. Orbital Decay in Binaries with Evolved Stars

    Science.gov (United States)

    Sun, Meng; Arras, Phil; Weinberg, Nevin N.; Troup, Nicholas; Majewski, Steven R.

    2018-01-01

    Two mechanisms are often invoked to explain tidal friction in binary systems. The ``dynamical tide” is the resonant excitation of internal gravity waves by the tide, and their subsequent damping by nonlinear fluid processes or thermal diffusion. The ``equilibrium tide” refers to non-resonant excitation of fluid motion in the star’s convection zone, with damping by interaction with the turbulent eddies. There have been numerous studies of these processes in main sequence stars, but less so on the subgiant and red giant branches. Motivated by the newly discovered close binary systems in the Apache Point Observatory Galactic Evolution Experiment (APOGEE-1), we have performed calculations of both the dynamical and equilibrium tide processes for stars over a range of mass as the star’s cease core hydrogen burning and evolve to shell burning. Even for stars which had a radiative core on the main sequence, the dynamical tide may have very large amplitude in the newly radiative core in post-main sequence, giving rise to wave breaking. The resulting large dynamical tide dissipation rate is compared to the equilibrium tide, and the range of secondary masses and orbital periods over which rapid orbital decay may occur will be discussed, as well as applications to close APOGEE binaries.

  3. Diverticular Disease: Traditional and Evolving Paradigms.

    Science.gov (United States)

    Lamanna, Lenore; Moran, Patricia E

    Diverticular disease includes diverticulosis, which are sac protrusions of the intestinal mucosa, and diverticulitis, inflammation of the diverticula. Diverticular disease is listed as one of the top 10 leading physician diagnoses for gastrointestinal disorders in outpatient clinic visits in the United States. There are several classifications of diverticular disease ranging from asymptomatic diverticulosis to diverticulitis with complications. Several theories are linked to the development of diverticula which includes the physiology of the colon itself, collagen cross-linking, and recently challenged, low-fiber intake. The differential diagnoses of lower abdominal pain in addition to diverticular disease have overlapping signs and symptoms, which can make a diagnosis challenging. Identification of the distinct signs and symptoms of each classification will assist the practitioner in making the correct diagnosis and lead to appropriate management. The findings from recent studies have changed the paradigm of diverticular disease. The purpose of this article is to discuss traditional dogma and evolving concepts in the pathophysiology, prevention, and management of diverticular disease. Practitioners must be knowledgeable about diverticular disease for improved outcomes.

  4. Minority games, evolving capitals and replicator dynamics

    International Nuclear Information System (INIS)

    Galla, Tobias; Zhang, Yi-Cheng

    2009-01-01

    We discuss a simple version of the minority game (MG) in which agents hold only one strategy each, but in which their capitals evolve dynamically according to their success and in which the total trading volume varies in time accordingly. This feature is known to be crucial for MGs to reproduce stylized facts of real market data. The stationary states and phase diagram of the model can be computed, and we show that the ergodicity breaking phase transition common for MGs, and marked by a divergence of the integrated response, is present also in this simplified model. An analogous majority game turns out to be relatively void of interesting features, and the total capital is found to diverge in time. Introducing a restraining force leads to a model akin to the replicator dynamics of evolutionary game theory, and we demonstrate that here a different type of phase transition is observed. Finally we briefly discuss the relation of this model with one strategy per player to more sophisticated minority games with dynamical capitals and several trading strategies per agent

  5. An evolving model of online bipartite networks

    Science.gov (United States)

    Zhang, Chu-Xu; Zhang, Zi-Ke; Liu, Chuang

    2013-12-01

    Understanding the structure and evolution of online bipartite networks is a significant task since they play a crucial role in various e-commerce services nowadays. Recently, various attempts have been tried to propose different models, resulting in either power-law or exponential degree distributions. However, many empirical results show that the user degree distribution actually follows a shifted power-law distribution, the so-called Mandelbrot’s law, which cannot be fully described by previous models. In this paper, we propose an evolving model, considering two different user behaviors: random and preferential attachment. Extensive empirical results on two real bipartite networks, Delicious and CiteULike, show that the theoretical model can well characterize the structure of real networks for both user and object degree distributions. In addition, we introduce a structural parameter p, to demonstrate that the hybrid user behavior leads to the shifted power-law degree distribution, and the region of power-law tail will increase with the increment of p. The proposed model might shed some lights in understanding the underlying laws governing the structure of real online bipartite networks.

  6. The Evolving Classification of Pulmonary Hypertension.

    Science.gov (United States)

    Foshat, Michelle; Boroumand, Nahal

    2017-05-01

    - An explosion of information on pulmonary hypertension has occurred during the past few decades. The perception of this disease has shifted from purely clinical to incorporate new knowledge of the underlying pathology. This transfer has occurred in light of advancements in pathophysiology, histology, and molecular medical diagnostics. - To update readers about the evolving understanding of the etiology and pathogenesis of pulmonary hypertension and to demonstrate how pathology has shaped the current classification. - Information presented at the 5 World Symposia on pulmonary hypertension held since 1973, with the last meeting occurring in 2013, was used in this review. - Pulmonary hypertension represents a heterogeneous group of disorders that are differentiated based on differences in clinical, hemodynamic, and histopathologic features. Early concepts of pulmonary hypertension were largely influenced by pharmacotherapy, hemodynamic function, and clinical presentation of the disease. The initial nomenclature for pulmonary hypertension segregated the clinical classifications from pathologic subtypes. Major restructuring of this disease classification occurred between the first and second symposia, which was the first to unite clinical and pathologic information in the categorization scheme. Additional changes were introduced in subsequent meetings, particularly between the third and fourth World Symposia meetings, when additional pathophysiologic information was gained. Discoveries in molecular diagnostics significantly progressed the understanding of idiopathic pulmonary arterial hypertension. Continued advancements in imaging modalities, mechanistic pathogenicity, and molecular biomarkers will enable physicians to define pulmonary hypertension phenotypes based on the pathobiology and allow for treatment customization.

  7. Evolving application of biomimetic nanostructured hydroxyapatite

    Directory of Open Access Journals (Sweden)

    Norberto Roveri

    2010-11-01

    Full Text Available Norberto Roveri, Michele IafiscoLaboratory of Environmental and Biological Structural Chemistry (LEBSC, Dipartimento di Chimica ‘G. Ciamician’, Alma Mater Studiorum, Università di Bologna, Bologna, ItalyAbstract: By mimicking Nature, we can design and synthesize inorganic smart materials that are reactive to biological tissues. These smart materials can be utilized to design innovative third-generation biomaterials, which are able to not only optimize their interaction with biological tissues and environment, but also mimic biogenic materials in their functionalities. The biomedical applications involve increasing the biomimetic levels from chemical composition, structural organization, morphology, mechanical behavior, nanostructure, and bulk and surface chemical–physical properties until the surface becomes bioreactive and stimulates cellular materials. The chemical–physical characteristics of biogenic hydroxyapatites from bone and tooth have been described, in order to point out the elective sides, which are important to reproduce the design of a new biomimetic synthetic hydroxyapatite. This review outlines the evolving applications of biomimetic synthetic calcium phosphates, details the main characteristics of bone and tooth, where the calcium phosphates are present, and discusses the chemical–physical characteristics of biomimetic calcium phosphates, methods of synthesizing them, and some of their biomedical applications.Keywords: hydroxyapatite, nanocrystals, biomimetism, biomaterials, drug delivery, remineralization

  8. Creativity from Constraints in Engineering Design

    DEFF Research Database (Denmark)

    Onarheim, Balder

    2012-01-01

    This paper investigates the role of constraints in limiting and enhancing creativity in engineering design. Based on a review of literature relating constraints to creativity, the paper presents a longitudinal participatory study from Coloplast A/S, a major international producer of disposable...... and ownership of formal constraints played a crucial role in defining their influence on creativity – along with the tacit constraints held by the designers. The designers were found to be highly constraint focused, and four main creative strategies for constraint manipulation were observed: blackboxing...

  9. A compendium of chameleon constraints

    International Nuclear Information System (INIS)

    Burrage, Clare; Sakstein, Jeremy

    2016-01-01

    The chameleon model is a scalar field theory with a screening mechanism that explains how a cosmologically relevant light scalar can avoid the constraints of intra-solar-system searches for fifth-forces. The chameleon is a popular dark energy candidate and also arises in f ( R ) theories of gravity. Whilst the chameleon is designed to avoid historical searches for fifth-forces it is not unobservable and much effort has gone into identifying the best observables and experiments to detect it. These results are not always presented for the same models or in the same language, a particular problem when comparing astrophysical and laboratory searches making it difficult to understand what regions of parameter space remain. Here we present combined constraints on the chameleon model from astrophysical and laboratory searches for the first time and identify the remaining windows of parameter space. We discuss the implications for cosmological chameleon searches and future small-scale probes.

  10. A compendium of chameleon constraints

    Energy Technology Data Exchange (ETDEWEB)

    Burrage, Clare [School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD (United Kingdom); Sakstein, Jeremy, E-mail: clare.burrage@nottingham.ac.uk, E-mail: jeremy.sakstein@port.ac.uk [Center for Particle Cosmology, Department of Physics and Astronomy, University of Pennsylvania, 209 S. 33rd St., Philadelphia, PA 19104 (United States)

    2016-11-01

    The chameleon model is a scalar field theory with a screening mechanism that explains how a cosmologically relevant light scalar can avoid the constraints of intra-solar-system searches for fifth-forces. The chameleon is a popular dark energy candidate and also arises in f ( R ) theories of gravity. Whilst the chameleon is designed to avoid historical searches for fifth-forces it is not unobservable and much effort has gone into identifying the best observables and experiments to detect it. These results are not always presented for the same models or in the same language, a particular problem when comparing astrophysical and laboratory searches making it difficult to understand what regions of parameter space remain. Here we present combined constraints on the chameleon model from astrophysical and laboratory searches for the first time and identify the remaining windows of parameter space. We discuss the implications for cosmological chameleon searches and future small-scale probes.

  11. Self-Imposed Creativity Constraints

    DEFF Research Database (Denmark)

    Biskjaer, Michael Mose

    2013-01-01

    Abstract This dissertation epitomizes three years of research guided by the research question: how can we conceptualize creative self-binding as a resource in art and design processes? Concretely, the dissertation seeks to offer insight into the puzzling observation that highly skilled creative...... practitioners sometimes freely and intentionally impose rigid rules, peculiar principles, and other kinds of creative obstructions on themselves as a means to spur momentum in the process and reach a distinctly original outcome. To investigate this the dissertation is composed of four papers (Part II) framed...... of analysis. Informed by the insight that constraints both enable and restrain creative agency, the dissertation’s main contention is that creative self- binding may profitably be conceptualized as the exercise of self-imposed creativity constraints. Thus, the dissertation marks an analytical move from vague...

  12. Unitarity constraints on trimaximal mixing

    International Nuclear Information System (INIS)

    Kumar, Sanjeev

    2010-01-01

    When the neutrino mass eigenstate ν 2 is trimaximally mixed, the mixing matrix is called trimaximal. The middle column of the trimaximal mixing matrix is identical to tribimaximal mixing and the other two columns are subject to unitarity constraints. This corresponds to a mixing matrix with four independent parameters in the most general case. Apart from the two Majorana phases, the mixing matrix has only one free parameter in the CP conserving limit. Trimaximality results in interesting interplay between mixing angles and CP violation. A notion of maximal CP violation naturally emerges here: CP violation is maximal for maximal 2-3 mixing. Similarly, there is a natural constraint on the deviation from maximal 2-3 mixing which takes its maximal value in the CP conserving limit.

  13. Financial Constraints and Franchising Decisions

    OpenAIRE

    Kai-Uwe Kuhn; Francine Lafontaine; Ying Fan

    2013-01-01

    We study how the financial constraints of agents affect the behavior of principals in the context of franchising. We develop an empirical model of franchising starting with a principal-agent framework that emphasizes the role of franchisees' collateral from an incentive perspective. We estimate the determinants of chains' entry (into franchising) and growth decisions using data on franchised chains and data on local macroeconomic conditions. In particular, we use collateralizable housing weal...

  14. Galaxies in the Early Universe

    DEFF Research Database (Denmark)

    Krogager, Jens-Kristian

    Understanding how galaxies evolved from the early Universe through cosmic time is a fundamental part of modern astrophysics. In order to study this evolution it is important to sample the galaxies at various times in a consistent way through time. In regular luminosity selected samples, our...

  15. Analysis of Space Tourism Constraints

    Science.gov (United States)

    Bonnal, Christophe

    2002-01-01

    Space tourism appears today as a new Eldorado in a relatively near future. Private operators are already proposing services for leisure trips in Low Earth Orbit, and some happy few even tested them. But are these exceptional events really marking the dawn of a new space age ? The constraints associated to the space tourism are severe : - the economical balance of space tourism is tricky; development costs of large manned - the technical definition of such large vehicles is challenging, mainly when considering - the physiological aptitude of passengers will have a major impact on the mission - the orbital environment will also lead to mission constraints on aspects such as radiation, However, these constraints never appear as show-stoppers and have to be dealt with pragmatically: - what are the recommendations one can make for future research in the field of space - which typical roadmap shall one consider to develop realistically this new market ? - what are the synergies with the conventional missions and with the existing infrastructure, - how can a phased development start soon ? The paper proposes hints aiming at improving the credibility of Space Tourism and describes the orientations to follow in order to solve the major hurdles found in such an exciting development.

  16. Infrared Constraint on Ultraviolet Theories

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, Yuhsin [Cornell Univ., Ithaca, NY (United States)

    2012-08-01

    While our current paradigm of particle physics, the Standard Model (SM), has been extremely successful at explaining experiments, it is theoretically incomplete and must be embedded into a larger framework. In this thesis, we review the main motivations for theories beyond the SM (BSM) and the ways such theories can be constrained using low energy physics. The hierarchy problem, neutrino mass and the existence of dark matter (DM) are the main reasons why the SM is incomplete . Two of the most plausible theories that may solve the hierarchy problem are the Randall-Sundrum (RS) models and supersymmetry (SUSY). RS models usually suffer from strong flavor constraints, while SUSY models produce extra degrees of freedom that need to be hidden from current experiments. To show the importance of infrared (IR) physics constraints, we discuss the flavor bounds on the anarchic RS model in both the lepton and quark sectors. For SUSY models, we discuss the difficulties in obtaining a phenomenologically allowed gaugino mass, its relation to R-symmetry breaking, and how to build a model that avoids this problem. For the neutrino mass problem, we discuss the idea of generating small neutrino masses using compositeness. By requiring successful leptogenesis and the existence of warm dark matter (WDM), we can set various constraints on the hidden composite sector. Finally, to give an example of model independent bounds from collider experiments, we show how to constrain the DM–SM particle interactions using collider results with an effective coupling description.

  17. Isocurvature constraints on portal couplings

    Energy Technology Data Exchange (ETDEWEB)

    Kainulainen, Kimmo; Nurmi, Sami; Vaskonen, Ville [Department of Physics, University of Jyväskylä, P.O.Box 35 (YFL), FI-40014 University of Jyväskylä (Finland); Tenkanen, Tommi; Tuominen, Kimmo, E-mail: kimmo.kainulainen@jyu.fi, E-mail: sami.t.nurmi@jyu.fi, E-mail: tommi.tenkanen@helsinki.fi, E-mail: kimmo.i.tuominen@helsinki.fi, E-mail: ville.vaskonen@jyu.fi [Department of Physics, University of Helsinki P.O. Box 64, FI-00014, Helsinki (Finland)

    2016-06-01

    We consider portal models which are ultraweakly coupled with the Standard Model, and confront them with observational constraints on dark matter abundance and isocurvature perturbations. We assume the hidden sector to contain a real singlet scalar s and a sterile neutrino ψ coupled to s via a pseudoscalar Yukawa term. During inflation, a primordial condensate consisting of the singlet scalar s is generated, and its contribution to the isocurvature perturbations is imprinted onto the dark matter abundance. We compute the total dark matter abundance including the contributions from condensate decay and nonthermal production from the Standard Model sector. We then use the Planck limit on isocurvature perturbations to derive a novel constraint connecting dark matter mass and the singlet self coupling with the scale of inflation: m {sub DM}/GeV ∼< 0.2λ{sub s}{sup 3/8} ( H {sub *}/10{sup 11} GeV){sup −3/2}. This constraint is relevant in most portal models ultraweakly coupled with the Standard Model and containing light singlet scalar fields.

  18. Quantum mechanics in an evolving Hilbert space

    Science.gov (United States)

    Artacho, Emilio; O'Regan, David D.

    2017-03-01

    Many basis sets for electronic structure calculations evolve with varying external parameters, such as moving atoms in dynamic simulations, giving rise to extra derivative terms in the dynamical equations. Here we revisit these derivatives in the context of differential geometry, thereby obtaining a more transparent formalization, and a geometrical perspective for better understanding the resulting equations. The effect of the evolution of the basis set within the spanned Hilbert space separates explicitly from the effect of the turning of the space itself when moving in parameter space, as the tangent space turns when moving in a curved space. New insights are obtained using familiar concepts in that context such as the Riemann curvature. The differential geometry is not strictly that for curved spaces as in general relativity, a more adequate mathematical framework being provided by fiber bundles. The language used here, however, will be restricted to tensors and basic quantum mechanics. The local gauge implied by a smoothly varying basis set readily connects with Berry's formalism for geometric phases. Generalized expressions for the Berry connection and curvature are obtained for a parameter-dependent occupied Hilbert space spanned by nonorthogonal Wannier functions. The formalism is applicable to basis sets made of atomic-like orbitals and also more adaptative moving basis functions (such as in methods using Wannier functions as intermediate or support bases), but should also apply to other situations in which nonorthogonal functions or related projectors should arise. The formalism is applied to the time-dependent quantum evolution of electrons for moving atoms. The geometric insights provided here allow us to propose new finite-difference time integrators, and also better understand those already proposed.

  19. Public participation at Fernald: FERMCO's evolving role

    International Nuclear Information System (INIS)

    Williams, J.B.; Fellman, R.W.; Brettschneider, D.J.

    1995-01-01

    In an effort to improve public involvement in the site restoration decision making process, the DOE has established site specific advisory boards, of which the Fernald Citizens Task Force is one. The Fernald Task Force is focused on making recommendations in four areas: (1) What should be the future use of the site? (2) Determinations of cleanup levels (how clean is clean?) (3) Where should the wastes be disposed of? (4) What should be the cleanup priorities? Because these questions are being asked very early in the decision-making process, the answers are necessarily qualified, and are based on a combination of preliminary data, assumptions, and professional judgment. The requirement to make progress in the absence of accurate data has necessitated FERMCO and the Task Force to employ an approach similar to sensitivity analysis, in which a range of possible data values are evaluated and the relative importance of the various factors is assessed. Because of its charter to provide recommendations of future site use, the Task Force has developed a sitewide perspective, compared to the more common operable unit specific focus of public participation under CERCLA. The relationship between FERMCO and the Task Force is evolving toward one of partnership with DOE in managing the obstacles and hidden opportunities for success. The Task Force likely will continue to participate in the Fernald project long after its initial recommendations have been made. DOE already has made the commitment that the process of public participation will extend into the Remedial Design phase. There is substantial reason for optimism that continuing the Task Force process through the design phase will assist in developing the appropriate balance of cost and engineered protectiveness

  20. Relaxations of semiring constraint satisfaction problems

    CSIR Research Space (South Africa)

    Leenen, L

    2007-03-01

    Full Text Available The Semiring Constraint Satisfaction Problem (SCSP) framework is a popular approach for the representation of partial constraint satisfaction problems. In this framework preferences can be associated with tuples of values of the variable domains...

  1. Transmission and capacity pricing and constraints

    International Nuclear Information System (INIS)

    Fusco, M.

    1999-01-01

    A series of overhead viewgraphs accompanied this presentation which discussed the following issues regarding the North American electric power industry: (1) capacity pricing transmission constraints, (2) nature of transmission constraints, (3) consequences of transmission constraints, and (4) prices as market evidence. Some solutions suggested for pricing constraints included the development of contingent contracts, back-up power in supply regions, and new line capacity construction. 8 tabs., 20 figs

  2. Ant colony optimization and constraint programming

    CERN Document Server

    Solnon, Christine

    2013-01-01

    Ant colony optimization is a metaheuristic which has been successfully applied to a wide range of combinatorial optimization problems. The author describes this metaheuristic and studies its efficiency for solving some hard combinatorial problems, with a specific focus on constraint programming. The text is organized into three parts. The first part introduces constraint programming, which provides high level features to declaratively model problems by means of constraints. It describes the main existing approaches for solving constraint satisfaction problems, including complete tree search

  3. The Ambiguous Role of Constraints in Creativity

    DEFF Research Database (Denmark)

    Biskjær, Michael Mose; Onarheim, Balder; Wiltschnig, Stefan

    2011-01-01

    The relationship between creativity and constraints is often described in the literature either in rather imprecise, general concepts or in relation to very specific domains. Cross-domain and cross-disciplinary takes on how the handling of constraints influences creative activities are rare. In t......-disciplinary research into the ambiguous role of constraints in creativity....

  4. Learning and Parallelization Boost Constraint Search

    Science.gov (United States)

    Yun, Xi

    2013-01-01

    Constraint satisfaction problems are a powerful way to abstract and represent academic and real-world problems from both artificial intelligence and operations research. A constraint satisfaction problem is typically addressed by a sequential constraint solver running on a single processor. Rather than construct a new, parallel solver, this work…

  5. A general treatment of dynamic integrity constraints

    NARCIS (Netherlands)

    de Brock, EO

    This paper introduces a general, set-theoretic model for expressing dynamic integrity constraints, i.e., integrity constraints on the state changes that are allowed in a given state space. In a managerial context, such dynamic integrity constraints can be seen as representations of "real world"

  6. Modelling of web-based virtual university administration for Nigerian ...

    African Journals Online (AJOL)

    This research work focused on development of a model of web based virtual University Administration for Nigerian universities. This is necessary as there is still a noticeable administrative constraint in our Universities, the establishment of many University Web portals notwithstanding. More efforts are therefore needed to ...

  7. Evolving R Coronae Borealis Stars with MESA

    Science.gov (United States)

    Clayton, Geoffrey C.; Lauer, Amber; Chatzopoulos, Emmanouil; Frank, Juhan

    2018-01-01

    being a WD. Solving the mystery of how the RCB stars evolve will lead to a better understanding of other important types of stellar merger events such as Type Ia SNe.

  8. Mechanics of evolving thin film structures

    Science.gov (United States)

    Liang, Jim

    In the Stranski-Krastanov system, the lattice mismatch between the film and the substrate causes the film to break into islands. During annealing, both the surface energy and the elastic energy drive the islands to coarsen. Motivated by several related studies, we suggest that stable islands should form when a stiff ceiling is placed at a small gap above the film. We show that the role of elasticity is reversed: with the ceiling, the total elastic energy stored in the system increases as the islands coarsen laterally. Consequently, the islands select an equilibrium size to minimize the combined elastic energy and surface energy. In lithographically-induced self-assembly, when a two-phase fluid confined between parallel substrates is subjected to an electric field, one phase can self-assemble into a triangular lattice of islands in another phase. We describe a theory of the stability of the island lattice. The islands select the equilibrium diameter to minimize the combined interface energy and electrostatic energy. Furthermore, we study compressed SiGe thin film islands fabricated on a glass layer, which itself lies on a silicon wafer. Upon annealing, the glass flows, and the islands relax. A small island relaxes by in-plane expansion. A large island, however, wrinkles at the center before the in-plane relaxation arrives. The wrinkles may cause significant tensile stress in the island, leading to fracture. We model the island by the von Karman plate theory and the glass layer by the Reynolds lubrication theory. Numerical simulations evolve the in-plane expansion and the wrinkles simultaneously. We determine the critical island size, below which in-plane expansion prevails over wrinkling. Finally, in devices that integrate dissimilar materials in small dimensions, crack extension in one material often accompanies inelastic deformation in another. We analyze a channel crack advancing in an elastic film under tension, while an underlayer creeps. We use a two

  9. Coronal Loops: Evolving Beyond the Isothermal Approximation

    Science.gov (United States)

    Schmelz, J. T.; Cirtain, J. W.; Allen, J. D.

    2002-05-01

    Are coronal loops isothermal? A controversy over this question has arisen recently because different investigators using different techniques have obtained very different answers. Analysis of SOHO-EIT and TRACE data using narrowband filter ratios to obtain temperature maps has produced several key publications that suggest that coronal loops may be isothermal. We have constructed a multi-thermal distribution for several pixels along a relatively isolated coronal loop on the southwest limb of the solar disk using spectral line data from SOHO-CDS taken on 1998 Apr 20. These distributions are clearly inconsistent with isothermal plasma along either the line of sight or the length of the loop, and suggested rather that the temperature increases from the footpoints to the loop top. We speculated originally that these differences could be attributed to pixel size -- CDS pixels are larger, and more `contaminating' material would be expected along the line of sight. To test this idea, we used CDS iron line ratios from our data set to mimic the isothermal results from the narrowband filter instruments. These ratios indicated that the temperature gradient along the loop was flat, despite the fact that a more complete analysis of the same data showed this result to be false! The CDS pixel size was not the cause of the discrepancy; rather, the problem lies with the isothermal approximation used in EIT and TRACE analysis. These results should serve as a strong warning to anyone using this simplistic method to obtain temperature. This warning is echoed on the EIT web page: ``Danger! Enter at your own risk!'' In other words, values for temperature may be found, but they may have nothing to do with physical reality. Solar physics research at the University of Memphis is supported by NASA grant NAG5-9783. This research was funded in part by the NASA/TRACE MODA grant for Montana State University.

  10. Constraint Specialisation in Horn Clause Verification

    DEFF Research Database (Denmark)

    Kafle, Bishoksan; Gallagher, John Patrick

    2015-01-01

    We present a method for specialising the constraints in constrained Horn clauses with respect to a goal. We use abstract interpretation to compute a model of a query-answer transformation of a given set of clauses and a goal. The effect is to propagate the constraints from the goal top......-down and propagate answer constraints bottom-up. Our approach does not unfold the clauses at all; we use the constraints from the model to compute a specialised version of each clause in the program. The approach is independent of the abstract domain and the constraints theory underlying the clauses. Experimental...

  11. Constraint specialisation in Horn clause verification

    DEFF Research Database (Denmark)

    Kafle, Bishoksan; Gallagher, John Patrick

    2017-01-01

    We present a method for specialising the constraints in constrained Horn clauses with respect to a goal. We use abstract interpretation to compute a model of a query–answer transformed version of a given set of clauses and a goal. The constraints from the model are then used to compute...... a specialised version of each clause. The effect is to propagate the constraints from the goal top-down and propagate answer constraints bottom-up. The specialisation procedure can be repeated to yield further specialisation. The approach is independent of the abstract domain and the constraint theory...

  12. Sustaining Community-University Collaborations: The Durham University Model

    Directory of Open Access Journals (Sweden)

    Andrew Russell

    2011-11-01

    Full Text Available Durham University has initiated a community outreach and engagement program based on an evolving multifaceted model. This article analyses the components of the model and looks at how our work at Durham has become increasingly embedded in the structures and processes of the university as it has developed. The strengths and weaknesses in what has been achieved are highlighted, as is the future vision for the further development of this innovative community-university program. Keywords Public engagement; community partnerships; employer supported volunteering; corporate social responsibility

  13. Nuclear energy and external constraints

    International Nuclear Information System (INIS)

    Lattes, R.; Thiriet, L.

    1983-01-01

    The structural factors of this crisis probably predominate over factors arising out the economic situation, even if explanations vary in this respect. In this article devoted to nuclear energy, a possible means of Loosering external constraints the current international economic environment is firstly outlined; the context in which the policies of industrialized countries, and therefore that of France, must be developed. An examination of the possible role of energy policies in general and nuclear policies in particular as an instrument of economic policy in providing a partial solution to this crisis, will then enable to quantitatively evaluate the effects of such policies at a national level [fr

  14. Deconstructing the neutrino mass constraint from galaxy redshift surveys

    Science.gov (United States)

    Boyle, Aoife; Komatsu, Eiichiro

    2018-03-01

    The total mass of neutrinos can be constrained in a number of ways using galaxy redshift surveys. Massive neutrinos modify the expansion rate of the Universe, which can be measured using baryon acoustic oscillations (BAOs) or the Alcock-Paczynski (AP) test. Massive neutrinos also change the structure growth rate and the amplitude of the matter power spectrum, which can be measured using redshift-space distortions (RSD). We use the Fisher matrix formalism to disentangle these information sources, to provide projected neutrino mass constraints from each of these probes alone and to determine how sensitive each is to the assumed cosmological model. We isolate the distinctive effect of neutrino free-streaming on the matter power spectrum and structure growth rate as a signal unique to massive neutrinos that can provide the most robust constraints, which are relatively insensitive to extensions to the cosmological model beyond ΛCDM . We also provide forecasted constraints using all of the information contained in the observed galaxy power spectrum combined, and show that these maximally optimistic constraints are primarily limited by the accuracy to which the optical depth of the cosmic microwave background, τ, is known.

  15. Constraints on cosmological parameters in power-law cosmology

    International Nuclear Information System (INIS)

    Rani, Sarita; Singh, J.K.; Altaibayeva, A.; Myrzakulov, R.; Shahalam, M.

    2015-01-01

    In this paper, we examine observational constraints on the power law cosmology; essentially dependent on two parameters H 0 (Hubble constant) and q (deceleration parameter). We investigate the constraints on these parameters using the latest 28 points of H(z) data and 580 points of Union2.1 compilation data and, compare the results with the results of ΛCDM . We also forecast constraints using a simulated data set for the future JDEM, supernovae survey. Our studies give better insight into power law cosmology than the earlier done analysis by Kumar [arXiv:1109.6924] indicating it tuning well with Union2.1 compilation data but not with H(z) data. However, the constraints obtained on and i.e. H 0 average and q average using the simulated data set for the future JDEM, supernovae survey are found to be inconsistent with the values obtained from the H(z) and Union2.1 compilation data. We also perform the statefinder analysis and find that the power-law cosmological models approach the standard ΛCDM model as q → −1. Finally, we observe that although the power law cosmology explains several prominent features of evolution of the Universe, it fails in details

  16. Developmental constraint of insect audition

    Directory of Open Access Journals (Sweden)

    Strauß Johannes

    2006-12-01

    Full Text Available Abstract Background Insect ears contain very different numbers of sensory cells, from only one sensory cell in some moths to thousands of sensory cells, e.g. in cicadas. These differences still await functional explanation and especially the large numbers in cicadas remain puzzling. Insects of the different orders have distinct developmental sequences for the generation of auditory organs. These sensory cells might have different functions depending on the developmental stages. Here we propose that constraints arising during development are also important for the design of insect ears and might influence cell numbers of the adults. Presentation of the hypothesis We propose that the functional requirements of the subadult stages determine the adult complement of sensory units in the auditory system of cicadas. The hypothetical larval sensory organ should function as a vibration receiver, representing a functional caenogenesis. Testing the hypothesis Experiments at different levels have to be designed to test the hypothesis. Firstly, the neuroanatomy of the larval sense organ should be analyzed to detail. Secondly, the function should be unraveled neurophysiologically and behaviorally. Thirdly, the persistence of the sensory cells and the rebuilding of the sensory organ to the adult should be investigated. Implications of the hypothesis Usually, the evolution of insect ears is viewed with respect to physiological and neuronal mechanisms of sound perception. This view should be extended to the development of sense organs. Functional requirements during postembryonic development may act as constraints for the evolution of adult organs, as exemplified with the auditory system of cicadas.

  17. Observational constraints on undulant cosmologies

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-10-01

    In an undulant universe, cosmic expansion is characterized by alternating periods of acceleration and deceleration. We examine cosmologies in which the dark-energy equation of state varies periodically with the number of e-foldings of the scale factor of the universe, and use observations to constrain the frequency of oscillation. We find a tension between a forceful response to the cosmic coincidence problem and the standard treatment of structure formation.

  18. Approach to plant automation with evolving technology

    International Nuclear Information System (INIS)

    White, J.D.

    1989-01-01

    The US Department of Energy has provided support to Oak Ridge National Laboratory in order to pursue research leading to advanced, automated control of new innovative liquid-metal-cooled nuclear power plants. The purpose of this effort is to conduct research that will help to ensure improved operability, reliability, and safety for advanced LMRs. The plan adopted to achieve these program goals in an efficient and timely manner consists of utilizing, and advancing where required, state-of-the-art controls technology through close interaction with other national laboratories, universities, industry and utilities. A broad range of applications for the control systems strategies and the design environment developed in the course of this program is likely. A natural evolution of automated control in nuclear power plants is envisioned by ORNL to be a phased transition from today's situation of some analog control at the subsystem level with significant operator interaction to the future capability for completely automated digital control with operator supervision. The technical accomplishments provided by this program will assist the industry to accelerate this transition and provide greater economy and safety. The development of this transition to advanced, automated control system designs is expected to have extensive benefits in reduced operating costs, fewer outages, enhanced safety, improved licensability, and improved public acceptance for commercial nuclear power plants. 24 refs

  19. Star formation in evolving molecular clouds

    Science.gov (United States)

    Völschow, M.; Banerjee, R.; Körtgen, B.

    2017-09-01

    Molecular clouds are the principle stellar nurseries of our universe; they thus remain a focus of both observational and theoretical studies. From observations, some of the key properties of molecular clouds are well known but many questions regarding their evolution and star formation activity remain open. While numerical simulations feature a large number and complexity of involved physical processes, this plethora of effects may hide the fundamentals that determine the evolution of molecular clouds and enable the formation of stars. Purely analytical models, on the other hand, tend to suffer from rough approximations or a lack of completeness, limiting their predictive power. In this paper, we present a model that incorporates central concepts of astrophysics as well as reliable results from recent simulations of molecular clouds and their evolutionary paths. Based on that, we construct a self-consistent semi-analytical framework that describes the formation, evolution, and star formation activity of molecular clouds, including a number of feedback effects to account for the complex processes inside those objects. The final equation system is solved numerically but at much lower computational expense than, for example, hydrodynamical descriptions of comparable systems. The model presented in this paper agrees well with a broad range of observational results, showing that molecular cloud evolution can be understood as an interplay between accretion, global collapse, star formation, and stellar feedback.

  20. Approach to plant automation with evolving technology

    International Nuclear Information System (INIS)

    White, J.D.

    1989-01-01

    This paper reports that the U.S. Department of Energy has provided support to Oak Ridge National Laboratory in order to pursue research leading to advanced, automated control of new innovative liquid-metal-cooled nuclear power plants. The purpose of this effort is to conduct research that will help to ensure improved operability, reliability, and safety for advanced LMRs. The plan adopted to achieve these program goals in an efficient and timely manner consists of utilizing, and advancing where required, state-of-the art controls technology through close interaction with other national laboratories, universities, industry and utilities. A broad range of applications for the control systems strategies and the design environment developed in the course of this program is likely. A natural evolution of automated control in nuclear power plants is envisioned by ORNL to be a phased transition from today's situation of some analog control at the subsystem level with significant operator interaction to the future capability for completely automated digital control with operator supervision. The technical accomplishments provided by this program will assist the industry to accelerate this transition and provide greater economy and safety. The development of this transition to advanced, automated control system designs is expected to have extensive benefits in reduced operating costs, fewer outages, enhanced safety, improved licensability, and improved public acceptance for commercial nuclear power plants

  1. The genotype-phenotype map of an evolving digital organism.

    Directory of Open Access Journals (Sweden)

    Miguel A Fortuna

    2017-02-01

    Full Text Available To understand how evolving systems bring forth novel and useful phenotypes, it is essential to understand the relationship between genotypic and phenotypic change. Artificial evolving systems can help us understand whether the genotype-phenotype maps of natural evolving systems are highly unusual, and it may help create evolvable artificial systems. Here we characterize the genotype-phenotype map of digital organisms in Avida, a platform for digital evolution. We consider digital organisms from a vast space of 10141 genotypes (instruction sequences, which can form 512 different phenotypes. These phenotypes are distinguished by different Boolean logic functions they can compute, as well as by the complexity of these functions. We observe several properties with parallels in natural systems, such as connected genotype networks and asymmetric phenotypic transitions. The likely common cause is robustness to genotypic change. We describe an intriguing tension between phenotypic complexity and evolvability that may have implications for biological evolution. On the one hand, genotypic change is more likely to yield novel phenotypes in more complex organisms. On the other hand, the total number of novel phenotypes reachable through genotypic change is highest for organisms with simple phenotypes. Artificial evolving systems can help us study aspects of biological evolvability that are not accessible in vastly more complex natural systems. They can also help identify properties, such as robustness, that are required for both human-designed artificial systems and synthetic biological systems to be evolvable.

  2. The genotype-phenotype map of an evolving digital organism.

    Science.gov (United States)

    Fortuna, Miguel A; Zaman, Luis; Ofria, Charles; Wagner, Andreas

    2017-02-01

    To understand how evolving systems bring forth novel and useful phenotypes, it is essential to understand the relationship between genotypic and phenotypic change. Artificial evolving systems can help us understand whether the genotype-phenotype maps of natural evolving systems are highly unusual, and it may help create evolvable artificial systems. Here we characterize the genotype-phenotype map of digital organisms in Avida, a platform for digital evolution. We consider digital organisms from a vast space of 10141 genotypes (instruction sequences), which can form 512 different phenotypes. These phenotypes are distinguished by different Boolean logic functions they can compute, as well as by the complexity of these functions. We observe several properties with parallels in natural systems, such as connected genotype networks and asymmetric phenotypic transitions. The likely common cause is robustness to genotypic change. We describe an intriguing tension between phenotypic complexity and evolvability that may have implications for biological evolution. On the one hand, genotypic change is more likely to yield novel phenotypes in more complex organisms. On the other hand, the total number of novel phenotypes reachable through genotypic change is highest for organisms with simple phenotypes. Artificial evolving systems can help us study aspects of biological evolvability that are not accessible in vastly more complex natural systems. They can also help identify properties, such as robustness, that are required for both human-designed artificial systems and synthetic biological systems to be evolvable.

  3. An Evolving Asymmetric Game for Modeling Interdictor-Smuggler Problems

    Science.gov (United States)

    2016-06-01

    ASYMMETRIC GAME FOR MODELING INTERDICTOR-SMUGGLER PROBLEMS by Richard J. Allain June 2016 Thesis Advisor: David L. Alderson Second Reader: W...DATES COVERED Master’s thesis 4. TITLE AND SUBTITLE AN EVOLVING ASYMMETRIC GAME FOR MODELING INTERDICTOR- SMUGGLER PROBLEMS 5. FUNDING NUMBERS 6...NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA THESIS Approved for public release; distribution is unlimited AN EVOLVING

  4. Adaptation of Escherichia coli to glucose promotes evolvability in lactose.

    Science.gov (United States)

    Phillips, Kelly N; Castillo, Gerardo; Wünsche, Andrea; Cooper, Tim F

    2016-02-01

    The selective history of a population can influence its subsequent evolution, an effect known as historical contingency. We previously observed that five of six replicate populations that were evolved in a glucose-limited environment for 2000 generations, then switched to lactose for 1000 generations, had higher fitness increases in lactose than populations started directly from the ancestor. To test if selection in glucose systematically increased lactose evolvability, we started 12 replay populations--six from a population subsample and six from a single randomly selected clone--from each of the six glucose-evolved founder populations. These replay populations and 18 ancestral populations were evolved for 1000 generations in a lactose-limited environment. We found that replay populations were initially slightly less fit in lactose than the ancestor, but were more evolvable, in that they increased in fitness at a faster rate and to higher levels. This result indicates that evolution in the glucose environment resulted in genetic changes that increased the potential of genotypes to adapt to lactose. Genome sequencing identified four genes--iclR, nadR, spoT, and rbs--that were mutated in most glucose-evolved clones and are candidates for mediating increased evolvability. Our results demonstrate that short-term selective costs during selection in one environment can lead to changes in evolvability that confer longer term benefits. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

  5. PCBA demand forecasting using an evolving Takagi-Sugeno system

    NARCIS (Netherlands)

    van Rooijen, M.; Almeida, R.J.; Kaymak, U.

    2016-01-01

    This paper investigates the use of using an evolving fuzzy system for printed circuit board (PCBA) demand forecasting. The algorithm is based on the evolving Takagi-Sugeno (eTS) fuzzy system, which has the ability to incorporate new patterns by changing its internal structure in an on-line fashion.

  6. Laplacian Estrada and normalized Laplacian Estrada indices of evolving graphs.

    Directory of Open Access Journals (Sweden)

    Yilun Shang

    Full Text Available Large-scale time-evolving networks have been generated by many natural and technological applications, posing challenges for computation and modeling. Thus, it is of theoretical and practical significance to probe mathematical tools tailored for evolving networks. In this paper, on top of the dynamic Estrada index, we study the dynamic Laplacian Estrada index and the dynamic normalized Laplacian Estrada index of evolving graphs. Using linear algebra techniques, we established general upper and lower bounds for these graph-spectrum-based invariants through a couple of intuitive graph-theoretic measures, including the number of vertices or edges. Synthetic random evolving small-world networks are employed to show the relevance of the proposed dynamic Estrada indices. It is found that neither the static snapshot graphs nor the aggregated graph can approximate the evolving graph itself, indicating the fundamental difference between the static and dynamic Estrada indices.

  7. Laplacian Estrada and normalized Laplacian Estrada indices of evolving graphs.

    Science.gov (United States)

    Shang, Yilun

    2015-01-01

    Large-scale time-evolving networks have been generated by many natural and technological applications, posing challenges for computation and modeling. Thus, it is of theoretical and practical significance to probe mathematical tools tailored for evolving networks. In this paper, on top of the dynamic Estrada index, we study the dynamic Laplacian Estrada index and the dynamic normalized Laplacian Estrada index of evolving graphs. Using linear algebra techniques, we established general upper and lower bounds for these graph-spectrum-based invariants through a couple of intuitive graph-theoretic measures, including the number of vertices or edges. Synthetic random evolving small-world networks are employed to show the relevance of the proposed dynamic Estrada indices. It is found that neither the static snapshot graphs nor the aggregated graph can approximate the evolving graph itself, indicating the fundamental difference between the static and dynamic Estrada indices.

  8. Exploring the Structure and Evolution of the Universe: Multi-Band Profiles of the Known Gamma-Ray Pulsars

    Science.gov (United States)

    1998-01-01

    As summarized in this pamphlet, some of the far-reaching underlying issues to be addressed include: What is the origin of the universe and its destiny; Why is the universe lumpy; How did the known structures of the universe evolve; How do galaxies evolve; How do massive black holes grow; How did the elemental composition of the universe evolve; What is the structure and behavior of matter in the extreme; and Is Einstein's general relativity theory right.

  9. Revisiting Robustness and Evolvability: Evolution in Weighted Genotype Spaces

    Science.gov (United States)

    Partha, Raghavendran; Raman, Karthik

    2014-01-01

    Robustness and evolvability are highly intertwined properties of biological systems. The relationship between these properties determines how biological systems are able to withstand mutations and show variation in response to them. Computational studies have explored the relationship between these two properties using neutral networks of RNA sequences (genotype) and their secondary structures (phenotype) as a model system. However, these studies have assumed every mutation to a sequence to be equally likely; the differences in the likelihood of the occurrence of various mutations, and the consequence of probabilistic nature of the mutations in such a system have previously been ignored. Associating probabilities to mutations essentially results in the weighting of genotype space. We here perform a comparative analysis of weighted and unweighted neutral networks of RNA sequences, and subsequently explore the relationship between robustness and evolvability. We show that assuming an equal likelihood for all mutations (as in an unweighted network), underestimates robustness and overestimates evolvability of a system. In spite of discarding this assumption, we observe that a negative correlation between sequence (genotype) robustness and sequence evolvability persists, and also that structure (phenotype) robustness promotes structure evolvability, as observed in earlier studies using unweighted networks. We also study the effects of base composition bias on robustness and evolvability. Particularly, we explore the association between robustness and evolvability in a sequence space that is AU-rich – sequences with an AU content of 80% or higher, compared to a normal (unbiased) sequence space. We find that evolvability of both sequences and structures in an AU-rich space is lesser compared to the normal space, and robustness higher. We also observe that AU-rich populations evolving on neutral networks of phenotypes, can access less phenotypic variation compared to

  10. Dynamics of Large Systems of Nonlinearly Evolving Units

    Science.gov (United States)

    Lu, Zhixin

    The dynamics of large systems of many nonlinearly evolving units is a general research area that has great importance for many areas in science and technology, including biology, computation by artificial neural networks, statistical mechanics, flocking in animal groups, the dynamics of coupled neurons in the brain, and many others. While universal principles and techniques are largely lacking in this broad area of research, there is still one particular phenomenon that seems to be broadly applicable. In particular, this is the idea of emergence, by which is meant macroscopic behaviors that "emerge" from a large system of many "smaller or simpler entities such that...large entities" [i.e., macroscopic behaviors] arise which "exhibit properties the smaller/simpler entities do not exhibit." In this thesis we investigate mechanisms and manifestations of emergence in four dynamical systems consisting many nonlinearly evolving units. These four systems are as follows. (a) We first study the motion of a large ensemble of many noninteracting particles in a slowly changing Hamiltonian system that undergoes a separatrix crossing. In such systems, we find that separatrix-crossing induces a counterintuitive effect. Specifically, numerical simulation of two sets of densely sprinkled initial conditions on two energy curves appears to suggest that the two energy curves, one originally enclosing the other, seemingly interchange their positions. This, however, is topologically forbidden. We resolve this paradox by introducing a numerical simulation method we call "robust" and study its consequences. (b) We next study the collective dynamics of oscillatory pacemaker neurons in Suprachiasmatic Nucleus (SCN), which, through synchrony, govern the circadian rhythm of mammals. We start from a high-dimensional description of the many coupled oscillatory neuronal units within the SCN. This description is based on a forced Kuramoto model. We then reduce the system dimensionality by using

  11. Declarative Programming with Temporal Constraints, in the Language CG

    Directory of Open Access Journals (Sweden)

    Lorina Negreanu

    2015-01-01

    Full Text Available Specifying and interpreting temporal constraints are key elements of knowledge representation and reasoning, with applications in temporal databases, agent programming, and ambient intelligence. We present and formally characterize the language CG, which tackles this issue. In CG, users are able to develop time-dependent programs, in a flexible and straightforward manner. Such programs can, in turn, be coupled with evolving environments, thus empowering users to control the environment’s evolution. CG relies on a structure for storing temporal information, together with a dedicated query mechanism. Hence, we explore the computational complexity of our query satisfaction problem. We discuss previous implementation attempts of CG and introduce a novel prototype which relies on logic programming. Finally, we address the issue of consistency and correctness of CG program execution, using the Event-B modeling approach.

  12. Declarative Programming with Temporal Constraints, in the Language CG.

    Science.gov (United States)

    Negreanu, Lorina

    2015-01-01

    Specifying and interpreting temporal constraints are key elements of knowledge representation and reasoning, with applications in temporal databases, agent programming, and ambient intelligence. We present and formally characterize the language CG, which tackles this issue. In CG, users are able to develop time-dependent programs, in a flexible and straightforward manner. Such programs can, in turn, be coupled with evolving environments, thus empowering users to control the environment's evolution. CG relies on a structure for storing temporal information, together with a dedicated query mechanism. Hence, we explore the computational complexity of our query satisfaction problem. We discuss previous implementation attempts of CG and introduce a novel prototype which relies on logic programming. Finally, we address the issue of consistency and correctness of CG program execution, using the Event-B modeling approach.

  13. The Evolving Context for Science and Society

    Science.gov (United States)

    Leshner, Alan I.

    2012-01-01

    The relationship between science and the rest of society is critical both to the support it receives from the public and to the receptivity of the broader citizenry to science's explanations of the nature of the world and to its other outputs. Science's ultimate usefulness depends on a receptive public. For example, given that science and technology are imbedded in virtually every issue of modern life, either as a cause or a cure, it is critical that the relationship be strong and that the role of science is well appreciated by society, or the impacts of scientific advances will fall short of their great potential. Unfortunately, a variety of problems have been undermining the science-society relationship for over a decade. Some problems emerge from within the scientific enterprise - like scientific misconduct or conflicts of interest - and tarnish or weaken its image and credibility. Other problems and stresses come from outside the enterprise. The most obvious external pressure is that the world economic situation is undermining the financial support of both the conduct and infrastructure of science. Other examples of external pressures include conflicts between what science is revealing and political or economic expediency - e.g., global climate change - or instances where scientific advances encroach upon core human values or beliefs - e.g., scientific understanding of the origins and evolution of the universe as compared to biblical accounts of creation. Significant efforts - some dramatically non-traditional for many in the scientific community - are needed to restore balance to the science-society relationship.

  14. The evolving genetic risk for sporadic ALS.

    Science.gov (United States)

    Gibson, Summer B; Downie, Jonathan M; Tsetsou, Spyridoula; Feusier, Julie E; Figueroa, Karla P; Bromberg, Mark B; Jorde, Lynn B; Pulst, Stefan M

    2017-07-18

    To estimate the genetic risk conferred by known amyotrophic lateral sclerosis (ALS)-associated genes to the pathogenesis of sporadic ALS (SALS) using variant allele frequencies combined with predicted variant pathogenicity. Whole exome sequencing and repeat expansion PCR of C9orf72 and ATXN2 were performed on 87 patients of European ancestry with SALS seen at the University of Utah. DNA variants that change the protein coding sequence of 31 ALS-associated genes were annotated to determine which were rare and deleterious as predicted by MetaSVM. The percentage of patients with SALS with a rare and deleterious variant or repeat expansion in an ALS-associated gene was calculated. An odds ratio analysis was performed comparing the burden of ALS-associated genes in patients with SALS vs 324 normal controls. Nineteen rare nonsynonymous variants in an ALS-associated gene, 2 of which were found in 2 different individuals, were identified in 21 patients with SALS. Further, 5 deleterious C9orf72 and 2 ATXN2 repeat expansions were identified. A total of 17.2% of patients with SALS had a rare and deleterious variant or repeat expansion in an ALS-associated gene. The genetic burden of ALS-associated genes in patients with SALS as predicted by MetaSVM was significantly higher than in normal controls. Previous analyses have identified SALS-predisposing variants only in terms of their rarity in normal control populations. By incorporating variant pathogenicity as well as variant frequency, we demonstrated that the genetic risk contributed by these genes for SALS is substantially lower than previous estimates. © 2017 American Academy of Neurology.

  15. Conformally connected universes

    International Nuclear Information System (INIS)

    Cantor, M.; Piran, T.

    1983-01-01

    A well-known difficulty associated with the conformal method for the solution of the general relativistic Hamiltonian constraint is the appearance of an aphysical ''bag of gold'' singularity at the nodal surface of the conformal factor. This happens whenever the background Ricci scalar is too large. Using a simple model, it is demonstrated that some of these singular solutions do have a physical meaning, and that these can be considered as initial data for Universe containing black holes, which are connected, in a conformally nonsingular way with each other. The relation between the ADM mass and the horizon area in this solution supports the cosmic censorship conjecture. (author)

  16. Research ethics and Institutional Review Boards. The influence of moral constraints on emotion research.

    Science.gov (United States)

    Sontag, Michael

    2012-01-01

    Researchers in the twenty-first century face a set of challenges unknown to researchers a half century ago--the need to justify the moral acceptability of their research methods through formal review processes. However, the role that moral constraints play in the development and demise of scientific theories has largely gone unappreciated. The rise of Institutional Review Boards (IRB) in the 1960s compounded the impact of moral constraints on scientific research and on the theories that develop out of such highly monitored research. To demonstrate the effects of moral constraints on scientific theory and research, this paper offers a history and analysis of the interaction between evolving moral standards and twentieth century emotion theory. Recommendations regarding IRB reform are also reviewed. The paper concludes by arguing that, while appropriate IRB reform is important, it cannot eliminate the need for careful reflection on the broader forces that shape scientific practice and understanding.

  17. Thermomechanical constraints and constitutive formulations in thermoelasticity

    Directory of Open Access Journals (Sweden)

    Baek S.

    2003-01-01

    Full Text Available We investigate three classes of constraints in a thermoelastic body: (i a deformation-temperature constraint, (ii a deformation-entropy constraint, and (iii a deformation-energy constraint. These constraints are obtained as limits of unconstrained thermoelastic materials and we show that constraints (ii and (iii are equivalent. By using a limiting procedure, we show that for the constraint (i, the entropy plays the role of a Lagrange multiplier while for (ii and (iii, the absolute temperature plays the role of Lagrange multiplier. We further demonstrate that the governing equations for materials subject to constraint (i are identical to those of an unconstrained material whose internal energy is an affine function of the entropy, while those for materials subject to constraints (ii and (iii are identical to those of an unstrained material whose Helmholtz potential is affine in the absolute temperature. Finally, we model the thermoelastic response of a peroxide-cured vulcanizate of natural rubber and show that imposing the constraint in which the volume change depends only on the internal energy leads to very good predictions (compared to experimental results of the stress and temperature response under isothermal and isentropic conditions.

  18. Astrophysical constraints on singlet scalars at LHC

    Science.gov (United States)

    Hertzberg, Mark P.; Masoumi, Ali

    2017-04-01

    We consider the viability of new heavy gauge singlet scalar particles at colliders such as the LHC . Our original motivation for this study came from the possibility of a new heavy particle of mass ~ TeV decaying significantly into two photons at colliders, such as LHC, but our analysis applies more broadly. We show that there are significant constraints from astrophysics and cosmology on the simplest UV complete models that incorporate such new particles and its associated collider signal. The simplest and most obvious UV complete model that incorporates such signals is that it arises from a new singlet scalar (or pseudo-scalar) coupled to a new electrically charged and colored heavy fermion. Here we show that these new fermions (and anti-fermions) would be produced in the early universe, then form new color singlet heavy mesons with light quarks, obtain a non-negligible freeze-out abundance, and remain in kinetic equilibrium until decoupling. These heavy mesons possess interesting phenomenology, dependent on their charge, including forming new bound states with electrons and protons. We show that a significant number of these heavy states would survive for the age of the universe and an appreciable number would eventually be contained within the earth and solar system. We show that this leads to detectable consequences, including the production of highly energetic events from annihilations on earth, new spectral lines, and, spectacularly, the destabilization of stars. The lack of detection of these consequences rules out such simple UV completions, putting pressure on the viability of such new particles at LHC . To incorporate such a scalar would require either much more complicated UV completions or even further new physics that provides a decay channel for the associated fermion.

  19. Astrophysical constraints on singlet scalars at LHC

    Energy Technology Data Exchange (ETDEWEB)

    Hertzberg, Mark P.; Masoumi, Ali, E-mail: mark.hertzberg@tufts.edu, E-mail: ali@cosmos.phy.tufts.edu [Institute of Cosmology, Department of Physics and Astronomy, Tufts University, Medford, MA 02155 (United States)

    2017-04-01

    We consider the viability of new heavy gauge singlet scalar particles at colliders such as the LHC . Our original motivation for this study came from the possibility of a new heavy particle of mass ∼ TeV decaying significantly into two photons at colliders, such as LHC, but our analysis applies more broadly. We show that there are significant constraints from astrophysics and cosmology on the simplest UV complete models that incorporate such new particles and its associated collider signal. The simplest and most obvious UV complete model that incorporates such signals is that it arises from a new singlet scalar (or pseudo-scalar) coupled to a new electrically charged and colored heavy fermion. Here we show that these new fermions (and anti-fermions) would be produced in the early universe, then form new color singlet heavy mesons with light quarks, obtain a non-negligible freeze-out abundance, and remain in kinetic equilibrium until decoupling. These heavy mesons possess interesting phenomenology, dependent on their charge, including forming new bound states with electrons and protons. We show that a significant number of these heavy states would survive for the age of the universe and an appreciable number would eventually be contained within the earth and solar system. We show that this leads to detectable consequences, including the production of highly energetic events from annihilations on earth, new spectral lines, and, spectacularly, the destabilization of stars. The lack of detection of these consequences rules out such simple UV completions, putting pressure on the viability of such new particles at LHC . To incorporate such a scalar would require either much more complicated UV completions or even further new physics that provides a decay channel for the associated fermion.

  20. Evolving herbal formulations in management of dengue fever.

    Science.gov (United States)

    Singh, Pawan Kumar; Rawat, Pooja

    Dengue is endemic in more than 100 countries and it is estimated that annually above 390 million infections occur globally. During the period between 1996-2015, a massive increase of more than 500 per cent has been recorded in number of dengue cases reported in India. Till date, there are no specific globally accepted treatments for dengue fever in any system of medicine. Dengue does not cause very high mortality if properly handled and is currently being managed by clinicians through various adjuvant and alternative therapeutic options. Various plant based preparations have been used in different parts of India for combating dengue and are simultaneously also being scientifically validated by researchers. However, number of such scientific validation studies on phytomedicines are very less in India. Out of twenty-two plants reported against dengue, only four have been studied scientifically. Azadirachta indica, Carica papaya, Hippophae rhamnoides and Cissampelos pareira extracts were found effective and demonstrated improvement in clinical symptoms and direct inhibitory effect on dengue virus. C. papaya clinical trial showed increase in platelet count and faster recovery. These plants may be explored further as probable candidates for drug discovery against dengue. There is a need to search more such herbal formulations, which are being practiced at local level, document properly and validate them scientifically to confirm efficacy, mechanistic action and safety, before use. The herbal formulations being used by communities are the low hanging fruits which may provide alternative or adjuvant therapy if proper validation, value addition and product development steps are followed. This paper aims to review the recent status of dengue cases, deaths and evolving curative herbal solutions adapted and reported from India to combat the disease. Copyright © 2017 Transdisciplinary University, Bangalore and World Ayurveda Foundation. Published by Elsevier B.V. All rights

  1. Promising mutant varieties of groundnut evolved through gamma irradiation

    International Nuclear Information System (INIS)

    Sinha, P.K.; Rahman, H.

    1980-01-01

    The Chotanagpur plateau region of Bihar is the main potential area for groundnut cultivation in the State. Var. AK 12-24 - an early, bunch type - has been the predominant variety under cultivation. Because of special nature of soil and rainfall pattern of this area, it is desirable to evolve a variety with early to mid-early maturity and bunch habit, but with improved yield potential over the ruling var. AK 12-24. Two bold podded mutants BP 1 and BP 2 were obtained throuo.h gamma irradiation of var 41-C which is a late maturing variety (135-140 days), spreading in habit and with medium kernel and pod size, whereas the mutant varieties have early (110-115 days for BP 1) to mid-early (115-120 days for BP 2) maturity, bunch habit and bold kernel and pods (HKW 55-60 gm for BP 1 and 60-66 gms for BP 2). Both have 20-25% higher yield potential over AK 12-24. The results of 3 years' yield evaluation trials at Kanke and one year minikit trials at different locations in Bihar show that BP 1 and BP 2 have significantly outyielded the check AK 12-24 and were at par with each other. Both varieties -because of their bold seededness - come under HPS type and have good export market. These varieties have now been released by the Rajendra Agricultural University as Sonya Bold 1 and Sonya Bold 2 for cultivation in Bihar. (author)

  2. The role of social toxicity in responses to a slowly-evolving environmental disaster: the case of amphibole asbestos exposure in Libby, Montana, USA.

    Science.gov (United States)

    Cline, Rebecca J W; Orom, Heather; Chung, Jae Eun; Hernandez, Tanis

    2014-09-01

    Experiencing a disaster has significant negative effects on psychological adjustment. Case study accounts point to two consistent trends in slowly-evolving environmental disasters: (a) patterns of negative social dynamics, and (b) relatively worse psychological outcomes than in natural disasters. Researchers have begun to explicitly postulate that the social consequences of slowly-evolving environmental disasters (e.g., community conflict) have their own effects on victims' psychological outcomes. This study tested a model of the relationship between those social consequences and psychological adjustment of victims of a slowly-evolving environmental disaster, specifically those whose health has been compromised by the amphibole asbestos disaster in Libby, MT. Results indicate that experiencing greater community conflict about the disaster was associated with greater family conflict about the disaster which, in turn, was associated with greater social constraints on talking with others about their disease, both directly and indirectly through experiencing stigmatization. Experiencing greater social constraints was associated with worse psychological adjustment, both directly and indirectly through failed social support. Findings have implications for understanding pathways by which social responses create negative effects on mental health in slowly-evolving environmental disasters. These pathways suggest points for prevention and response (e.g., social support, stigmatization of victims) for communities experiencing slowly-evolving environmental disasters.

  3. Constraints on a generalized deceleration parameter from cosmic chronometers

    Science.gov (United States)

    Mamon, Abdulla Al

    2018-04-01

    In this paper, we have proposed a generalized parametrization for the deceleration parameter q in order to study the evolutionary history of the universe. We have shown that the proposed model can reproduce three well known q-parametrized models for some specific values of the model parameter α. We have used the latest compilation of the Hubble parameter measurements obtained from the cosmic chronometer (CC) method (in combination with the local value of the Hubble constant H0) and the Type Ia supernova (SNIa) data to place constraints on the parameters of the model for different values of α. We have found that the resulting constraints on the deceleration parameter and the dark energy equation of state support the ΛCDM model within 1σ confidence level at the present epoch.

  4. From physical dose constraints to equivalent uniform dose constraints in inverse radiotherapy planning

    International Nuclear Information System (INIS)

    Thieke, Christian; Bortfeld, Thomas; Niemierko, Andrzej; Nill, Simeon

    2003-01-01

    Optimization algorithms in inverse radiotherapy planning need information about the desired dose distribution. Usually the planner defines physical dose constraints for each structure of the treatment plan, either in form of minimum and maximum doses or as dose-volume constraints. The concept of equivalent uniform dose (EUD) was designed to describe dose distributions with a higher clinical relevance. In this paper, we present a method to consider the EUD as an optimization constraint by using the method of projections onto convex sets (POCS). In each iteration of the optimization loop, for the actual dose distribution of an organ that violates an EUD constraint a new dose distribution is calculated that satisfies the EUD constraint, leading to voxel-based physical dose constraints. The new dose distribution is found by projecting the current one onto the convex set of all dose distributions fulfilling the EUD constraint. The algorithm is easy to integrate into existing inverse planning systems, and it allows the planner to choose between physical and EUD constraints separately for each structure. A clinical case of a head and neck tumor is optimized using three different sets of constraints: physical constraints for all structures, physical constraints for the target and EUD constraints for the organs at risk, and EUD constraints for all structures. The results show that the POCS method converges stable and given EUD constraints are reached closely

  5. Metric approach to quantum constraints

    International Nuclear Information System (INIS)

    Brody, Dorje C; Hughston, Lane P; Gustavsson, Anna C T

    2009-01-01

    A framework for deriving equations of motion for constrained quantum systems is introduced and a procedure for its implementation is outlined. In special cases, the proposed new method, which takes advantage of the fact that the space of pure states in quantum mechanics has both a symplectic structure and a metric structure, reduces to a quantum analogue of the Dirac theory of constraints in classical mechanics. Explicit examples involving spin-1/2 particles are worked out in detail: in the first example, our approach coincides with a quantum version of the Dirac formalism, while the second example illustrates how a situation that cannot be treated by Dirac's approach can nevertheless be dealt with in the present scheme.

  6. Constraints on vacuum energy from structure formation and Nucleosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Adams, Fred C.; Grohs, Evan [Physics Department, University of Michigan, 450 Church Street, Ann Arbor, MI, 48109 (United States); Alexander, Stephon [Physics Department, Brown University, 6127 Wilder Laboratory, Providence, RI, 02912 (United States); Mersini-Houghton, Laura, E-mail: fca@umich.edu, E-mail: stephon_alexander@brown.edu, E-mail: egrohs@umich.edu, E-mail: mersini@physics.unc.edu [Physics Department, University of North Carolina, 120 E. Cameron Avenue, Chapel Hill, NC, 27599 (United States)

    2017-03-01

    This paper derives an upper limit on the density ρ{sub Λ} of dark energy based on the requirement that cosmological structure forms before being frozen out by the eventual acceleration of the universe. By allowing for variations in both the cosmological parameters and the strength of gravity, the resulting constraint is a generalization of previous limits. The specific parameters under consideration include the amplitude Q of the primordial density fluctuations, the Planck mass M {sub pl}, the baryon-to-photon ratio η, and the density ratio Ω {sub M} /Ω {sub b} . In addition to structure formation, we use considerations from stellar structure and Big Bang Nucleosynthesis (BBN) to constrain these quantities. The resulting upper limit on the dimensionless density of dark energy becomes ρ{sub Λ}/ M {sub pl}{sup 4} < 10{sup −90}, which is ∼30 orders of magnitude larger than the value in our universe ρ{sub Λ}/ M {sub pl}4 ∼ 10{sup −120}. This new limit is much less restrictive than previous constraints because additional parameters are allowed to vary. With these generalizations, a much wider range of universes can develop cosmic structure and support observers. To constrain the constituent parameters, new BBN calculations are carried out in the regime where η and G = M {sub pl}{sup −2} are much larger than in our universe. If the BBN epoch were to process all of the protons into heavier elements, no hydrogen would be left behind to make water, and the universe would not be viable. However, our results show that some hydrogen is always left over, even under conditions of extremely large η and G , so that a wide range of alternate universes are potentially habitable.

  7. Causality Constraints in Conformal Field Theory

    CERN Multimedia

    CERN. Geneva

    2015-01-01

    Causality places nontrivial constraints on QFT in Lorentzian signature, for example fixing the signs of certain terms in the low energy Lagrangian. In d-dimensional conformal field theory, we show how such constraints are encoded in crossing symmetry of Euclidean correlators, and derive analogous constraints directly from the conformal bootstrap (analytically). The bootstrap setup is a Lorentzian four-point function corresponding to propagation through a shockwave. Crossing symmetry fixes the signs of certain log terms that appear in the conformal block expansion, which constrains the interactions of low-lying operators. As an application, we use the bootstrap to rederive the well known sign constraint on the (∂φ)4 coupling in effective field theory, from a dual CFT. We also find constraints on theories with higher spin conserved currents. Our analysis is restricted to scalar correlators, but we argue that similar methods should also impose nontrivial constraints on the interactions of spinni...

  8. Constraint Embedding for Multibody System Dynamics

    Science.gov (United States)

    Jain, Abhinandan

    2009-01-01

    This paper describes a constraint embedding approach for the handling of local closure constraints in multibody system dynamics. The approach uses spatial operator techniques to eliminate local-loop constraints from the system and effectively convert the system into tree-topology systems. This approach allows the direct derivation of recursive O(N) techniques for solving the system dynamics and avoiding the expensive steps that would otherwise be required for handling the closedchain dynamics. The approach is very effective for systems where the constraints are confined to small-subgraphs within the system topology. The paper provides background on the spatial operator O(N) algorithms, the extensions for handling embedded constraints, and concludes with some examples of such constraints.

  9. Use of dose constraints in public exposure

    International Nuclear Information System (INIS)

    Tageldein, Amged

    2015-02-01

    An overview of the dose constraints in public exposures has been carried out in this project. The establishment, development and the application of the concept of dose constraints are reviewed with regards to public exposure. The role of dose constraints in the process of optimization of radiation protection was described and has been showed that the concept of the dose constraints along with many other concept of radiation protection is widely applied in the optimization of exposure to radiation. From the beginning of the establishment of dose constraints as a concept in radiation protection, the International Commission of Radiological Protection (ICRP) has published a number of documents that provides detailed application related to radiation protection and safety of public exposure from ionizing radiation. This work provides an overview of such publications and related documents with special emphasis on optimization of public exposure using dose constraints. (au)

  10. Causality constraints in conformal field theory

    Energy Technology Data Exchange (ETDEWEB)

    Hartman, Thomas; Jain, Sachin; Kundu, Sandipan [Department of Physics, Cornell University,Ithaca, New York (United States)

    2016-05-17

    Causality places nontrivial constraints on QFT in Lorentzian signature, for example fixing the signs of certain terms in the low energy Lagrangian. In d dimensional conformal field theory, we show how such constraints are encoded in crossing symmetry of Euclidean correlators, and derive analogous constraints directly from the conformal bootstrap (analytically). The bootstrap setup is a Lorentzian four-point function corresponding to propagation through a shockwave. Crossing symmetry fixes the signs of certain log terms that appear in the conformal block expansion, which constrains the interactions of low-lying operators. As an application, we use the bootstrap to rederive the well known sign constraint on the (∂ϕ){sup 4} coupling in effective field theory, from a dual CFT. We also find constraints on theories with higher spin conserved currents. Our analysis is restricted to scalar correlators, but we argue that similar methods should also impose nontrivial constraints on the interactions of spinning operators.

  11. Constraint-based Word Segmentation for Chinese

    DEFF Research Database (Denmark)

    Christiansen, Henning; Bo, Li

    2014-01-01

    -hoc and statistically based methods. In this paper, we show experiments of implementing different approaches to CWSP in the framework of CHR Grammars [Christiansen, 2005] that provides a constraint solving approach to language analysis. CHR Grammars are based upon Constraint Handling Rules, CHR [Frühwirth, 1998, 2009......], which is a declarative, high-level programming language for specification and implementation of constraint solvers....

  12. Stability Constraints for Robust Model Predictive Control

    Directory of Open Access Journals (Sweden)

    Amanda G. S. Ottoni

    2015-01-01

    Full Text Available This paper proposes an approach for the robust stabilization of systems controlled by MPC strategies. Uncertain SISO linear systems with box-bounded parametric uncertainties are considered. The proposed approach delivers some constraints on the control inputs which impose sufficient conditions for the convergence of the system output. These stability constraints can be included in the set of constraints dealt with by existing MPC design strategies, in this way leading to the “robustification” of the MPC.

  13. Some cosmological constraints on gauge theories

    International Nuclear Information System (INIS)

    Schramm, D.N.

    1983-01-01

    In these lectures, a review is made of various constraints cosmology may place on gauge theories. Particular emphasis is placed on those constraints obtainable from Big Bang Nucleosynthesis, with only brief mention made of Big Bang Baryosynthesis. There is also a considerable discussion of astrophysical constraints on masses and lifetimes of neutrinos with specific mention of the 'missing mass (light)' problem of galactic dynamics. (orig./HSI)

  14. Sterile neutrinos in the early universe

    Energy Technology Data Exchange (ETDEWEB)

    Malaney, R.A. (Lawrence Livermore National Lab., CA (USA)); Fuller, G.M. (California Univ., San Diego, La Jolla, CA (USA). Dept. of Physics)

    1990-11-14

    We discuss the role played by right-handed sterile neutrinos in the early universe. We show how well known {sup 4}He constraint on the number of relativistic degrees of freedom at early times limits the equilibration of the right handed neutrino sea with the background plasma. We discuss how this allows interesting constraints to be placed on neutrino properties. In particular, a new limit on the Dirac mass of the neutrino is presented. 12 refs.

  15. Morphological Variation in Anuran Limbs: Constraints and Novelties.

    Science.gov (United States)

    Fabrezi, Marissa; Goldberg, Javier; Chuliver Pereyra, Mariana

    2017-09-01

    Anurans have three primary types of locomotion: walking, jumping, and swimming. Additionally, they may dig, climb, grasp, etc. All adult anurans have four limbs, with four fingers on the hands and five toes on the feet. We summarized and updated knowledge on the interspecific variation within anuran limbs, then discuss how developmental constraints (e.g., in size) and novelties may have influenced anuran diversification through the locomotion. We analyze morphological variation from limb bud stages up to the final limb form resulting from certain skeletal organization and growth. We find limited morphometric variations in the skeleton of different developmental modules (i.e., skull, trunk, urostyle, limbs) indicate that the anuran body shape is largely constrained. We identify specializations of the stylopodium, zeugopodium, and proximal carpals/tarsals that have evolved to facilitiate saltatorial locomotion. We show that the anuran prepollex and prehallux are not vestigial digits and that they have come to serve specialized function. Medial rotation of the manus in anurans appears to have evolved to help distribute the force of impact upon landing at the end of a jump. Additional skeletal elements in anuran limbs are intercalary elements and sesamoids. The intercalary elements appear within neobatrachians and are integrated with digital pads in lineages capable of locomotion on smooth vertical surfaces. They have allowed arboreal anurans to occupy a wide range of arboreal habitats. © 2017 Wiley Periodicals, Inc.

  16. Generalized Pauli constraints in small atoms

    DEFF Research Database (Denmark)

    Schilling, Christian; Altunbulak, Murat; Knecht, Stefan

    2018-01-01

    investigations have found evidence that these constraints are exactly saturated in several physically relevant systems, e.g., in a certain electronic state of the beryllium atom. It has been suggested that, in such cases, the constraints, rather than the details of the Hamiltonian, dictate the system......'s qualitative behavior. Here, we revisit this question with state-of-the-art numerical methods for small atoms. We find that the constraints are, in fact, not exactly saturated, but that they lie much closer to the surface defined by the constraints than the geometry of the problem would suggest. While...

  17. Production Team Maintenance: Systemic Constraints Impacting Implementation

    National Research Council Canada - National Science Library

    Moore, Terry

    1997-01-01

    .... Identified constraints included: integrating the PTM positioning strategy into the AMC corporate strategic planning process, manpower modeling simulator limitations, labor force authorizations and decentralization...

  18. Review of Minimal Flavor Constraints for Technicolor

    DEFF Research Database (Denmark)

    S. Fukano, Hidenori; Sannino, Francesco

    2010-01-01

    We analyze the constraints on the the vacuum polarization of the standard model gauge bosons from a minimal set of flavor observables valid for a general class of models of dynamical electroweak symmetry breaking. We will show that the constraints have a strong impact on the self-coupling and mas......We analyze the constraints on the the vacuum polarization of the standard model gauge bosons from a minimal set of flavor observables valid for a general class of models of dynamical electroweak symmetry breaking. We will show that the constraints have a strong impact on the self...

  19. Toward an automaton Constraint for Local Search

    Directory of Open Access Journals (Sweden)

    Jun He

    2009-10-01

    Full Text Available We explore the idea of using finite automata to implement new constraints for local search (this is already a successful technique in constraint-based global search. We show how it is possible to maintain incrementally the violations of a constraint and its decision variables from an automaton that describes a ground checker for that constraint. We establish the practicality of our approach idea on real-life personnel rostering problems, and show that it is competitive with the approach of [Pralong, 2007].

  20. Notes on Timed Concurrent Constraint Programming

    DEFF Research Database (Denmark)

    Nielsen, Mogens; Valencia, Frank D.

    2004-01-01

    and program reactive systems. This note provides a comprehensive introduction to the background for and central notions from the theory of tccp. Furthermore, it surveys recent results on a particular tccp calculus, ntcc, and it provides a classification of the expressive power of various tccp languages.......A constraint is a piece of (partial) information on the values of the variables of a system. Concurrent constraint programming (ccp) is a model of concurrency in which agents (also called processes) interact by telling and asking information (constraints) to and from a shared store (a constraint...

  1. 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......, dissimilar, and sometimes conflicting dimensions of the financial, legal, organisational, staffing, and academic autonomy of the host country, are compromising key aspects of their own autonomy and core mission?......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 determined by the structure and exercise of university autonomy settings at home and in the host countries, and that the process itself cannot be successfully achieved and maintained without changes in the autonomy settings. The key question the authors ask is to what degree universities, in embracing new...

  2. Language Learning within Academic Constraints.

    Science.gov (United States)

    Blue, George M.

    This paper reports on a research project that examined nonnative Southampton University (England) students' attitudes to continued language learning and the importance of language learning and cultural adaptation. A survey was administered to pre-sessional and in-sessional students that included information on background, past and present language…

  3. Cosmographic constraints from The Raychaudhuri Equation

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Crislane S.; Santos, Janilo [Universidade Federal do Rio Grande do Norte (UFRN), RN (Brazil)

    2011-07-01

    Full text: There is nowadays a great debate about the mechanism behind the observed cosmic acceleration. In the absence of a fundamental new physical theory, capable of joining the macro and the microphysics, a number of cosmological scenarios have been risen presupposing the existence of new fields in nature, such as quintessence scalar field and Chaplygin gas, for example. The aim of these cosmological models is indeed to derive a smooth function H(z), the so called Hubble function, which describes the expansion history of the universe, and as a further step to confront predictions with the observations. However, there is a direct method to map the expansion history of the universe in a model independent way. Recently it has been shown that luminous red galaxies can provide us with direct measurements of the expansion rate H(z) using differential age techniques. Indeed, at the moment we have only 11 estimates of H(z) lying in the redshift interval 0.1 ≤ z ≥ 1.75; however, in the near future, it is expected ∼ 1, 000 values of the Hubble function. In this way, cosmography is becoming a promising branch in cosmology. Here we investigate and discuss the use of the Raychaudhury equation as a cosmographic description and relate the expansion rate Θ of a congruence of world lines with the evolution of the Hubble function H(z). As is well known, the Raychaudhury equation is central to the understanding of gravitational attraction in astrophysics and cosmology. Our assumptions are that the underlying geometry of the universe is a flat Friedmann-Lemaitre-Robertson-Walker one and that gravity has an attractive effect. For a comoving observer we find that the expansion rate of a congruence is given by Θ = -3/2(1 + z)dH{sup 2}/dz, which we use to compare with the computed derivatives of H(z) measurements. We use this equation in order to put constraints in the parameters of the cosmological models of quintessence scalar field and Chaplygin gas. (author)

  4. On the efficacy of cinema, or what the visual system did not evolve to do

    Science.gov (United States)

    Cutting, James E.

    1989-01-01

    Spatial displays, and a constraint that they do not place on the use of spatial instruments are discussed. Much of the work done in visual perception by psychologists and by computer scientists has concerned displays that show the motion of rigid objects. Typically, if one assumes that objects are rigid, one can then proceed to understand how the constant shape of the object can be perceived (or computed) as it moves through space. The author maintains that photographs and cinema are visual displays that are also powerful forms of art. Their efficacy, in part, stems from the fact that, although viewpoint is constrained when composing them, it is not nearly so constrained when viewing them. It is obvious, according to the author, that human visual systems did not evolve to watch movies or look at photographs. Thus, what photographs and movies present must be allowed in the rule-governed system under which vision evolved. Machine-vision algorithms, to be applicable to human vision, should show the same types of tolerance.

  5. Effective University Teaching: Views of Australian University Students from Low Socio-Economic Status Backgrounds

    Science.gov (United States)

    Devlin, Marcia; O'Shea, Helen

    2012-01-01

    As the Australian higher education population further diversifies as a result of federal government policy changes, the collective understanding of effective university teaching in the Australian context will need to evolve to incorporate such shifts. The Australian Government has set clear targets for increased university participation of people…

  6. Project Seahorse evolves into major marine protector | IDRC ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    2012-10-29

    Oct 29, 2012 ... Project Seahorse evolves into major marine protector ... local people, have greatly improved the prospects of survival for threatened species. ... “We tackle issues on any political level or geographical scale, according to what ...

  7. Incremental Frequent Subgraph Mining on Large Evolving Graphs

    KAUST Repository

    Abdelhamid, Ehab; Canim, Mustafa; Sadoghi, Mohammad; Bhatta, Bishwaranjan; Chang, Yuan-Chi; Kalnis, Panos

    2017-01-01

    , such as social networks, utilize large evolving graphs. Mining these graphs using existing techniques is infeasible, due to the high computational cost. In this paper, we propose IncGM+, a fast incremental approach for continuous frequent subgraph mining problem

  8. Genetic Algorithms Evolve Optimized Transforms for Signal Processing Applications

    National Research Council Canada - National Science Library

    Moore, Frank; Babb, Brendan; Becke, Steven; Koyuk, Heather; Lamson, Earl, III; Wedge, Christopher

    2005-01-01

    .... The primary goal of the research described in this final report was to establish a methodology for using genetic algorithms to evolve coefficient sets describing inverse transforms and matched...

  9. Biofabrication : reappraising the definition of an evolving field

    NARCIS (Netherlands)

    Groll, Jürgen; Boland, Thomas; Blunk, Torsten; Burdick, Jason A; Cho, Dong-Woo; Dalton, Paul D; Derby, Brian; Forgacs, Gabor; Li, Qing; Mironov, Vladimir A; Moroni, Lorenzo; Nakamura, Makoto; Shu, Wenmiao; Takeuchi, Shoji; Vozzi, Giovanni; Woodfield, Tim B F; Xu, Tao; Yoo, James J; Malda, Jos|info:eu-repo/dai/nl/412461099

    2016-01-01

    Biofabrication is an evolving research field that has recently received significant attention. In particular, the adoption of Biofabrication concepts within the field of Tissue Engineering and Regenerative Medicine has grown tremendously, and has been accompanied by a growing inconsistency in

  10. Biofabrication : Reappraising the definition of an evolving field

    NARCIS (Netherlands)

    Groll, Jürgen; Boland, Thomas; Blunk, Torsten; Burdick, Jason A.; Cho, Dong Woo; Dalton, Paul D.; Derby, Brian; Forgacs, Gabor; Li, Qing; Mironov, Vladimir A.; Moroni, Lorenzo; Nakamura, Makoto; Shu, Wenmiao; Takeuchi, Shoji; Vozzi, Giovanni; Woodfield, Tim B.F.; Xu, Tao; Yoo, James J.; Malda, Jos

    2016-01-01

    Biofabrication is an evolving research field that has recently received significant attention. In particular, the adoption of Biofabrication concepts within the field of Tissue Engineering and Regenerative Medicine has grown tremendously, and has been accompanied by a growing inconsistency in

  11. Orthogonally Evolved AI to Improve Difficulty Adjustment in Video Games

    DEFF Research Database (Denmark)

    Hintze, Arend; Olson, Randal; Lehman, Joel Anthony

    2016-01-01

    Computer games are most engaging when their difficulty is well matched to the player's ability, thereby providing an experience in which the player is neither overwhelmed nor bored. In games where the player interacts with computer-controlled opponents, the difficulty of the game can be adjusted...... not only by changing the distribution of opponents or game resources, but also through modifying the skill of the opponents. Applying evolutionary algorithms to evolve the artificial intelligence that controls opponent agents is one established method for adjusting opponent difficulty. Less-evolved agents...... (i.e. agents subject to fewer generations of evolution) make for easier opponents, while highly-evolved agents are more challenging to overcome. In this publication we test a new approach for difficulty adjustment in games: orthogonally evolved AI, where the player receives support from collaborating...

  12. Evolving the Evolving: Territory, Place and Rewilding in the California Delta

    Directory of Open Access Journals (Sweden)

    Brett Milligan

    2017-10-01

    Full Text Available Current planning and legislation in California’s Sacramento-San Joaquin Delta call for the large-scale ecological restoration of aquatic and terrestrial habitats. These ecological mandates have emerged in response to the region’s infrastructural transformation and the Delta’s predominant use as the central logistical hub in the state’s vast water conveyance network. Restoration is an attempt to recover what was externalized by the logic and abstractions of this logistical infrastructure. However, based on findings from our research, which examined how people are using restored and naturalized landscapes in the Delta and how these landscapes are currently planned for, we argue that as mitigatory response, restoration planning continues some of the same spatial abstractions and inequities by failing to account for the Delta as an urbanized, cultural and unique place. In interpreting how these conditions have come to be, we give attention to a pluralistic landscape approach and a coevolutionary reading of planning, policy, science and landscapes to discuss the conservation challenges presented by “Delta as an Evolving Place”. We suggest that for rewilding efforts to be successful in the Delta, a range of proactive, opportunistic, grounded and participatory tactics will be required to shift towards a more socio-ecological approach.

  13. (N+1)-dimensional Lorentzian evolving wormholes supported by polytropic matter

    Energy Technology Data Exchange (ETDEWEB)

    Cataldo, Mauricio [Universidad del Bio-Bio, Departamento de Fisica, Facultad de Ciencias, Concepcion (Chile); Arostica, Fernanda; Bahamonde, Sebastian [Universidad de Concepcion, Departamento de Fisica, Concepcion (Chile)

    2013-08-15

    In this paper we study (N+1)-dimensional evolving wormholes supported by energy satisfying a polytropic equation of state. The considered evolving wormhole models are described by a constant redshift function and generalizes the standard flat Friedmann-Robertson-Walker spacetime. The polytropic equation of state allows us to consider in (3+1)-dimensions generalizations of the phantom energy and the generalized Chaplygin gas sources. (orig.)

  14. Cosmos and Creativity - Man in an evolving Universe as a creative, aesthetical Agent - some Peircean Remarks

    DEFF Research Database (Denmark)

    Sørensen, Bent; Thellefsen, Torkild Leo; Brier, Søren

    2011-01-01

    Any great new theoretical framework has an epistemological and an ontological aspect to its philosophy as well as an axiological one, and one needs to understand all three aspects in order to grasp the deep aspiration and idea of the theoretical framework. Presently, there is a widespread effort ...

  15. A new evolutionary system for evolving artificial neural networks.

    Science.gov (United States)

    Yao, X; Liu, Y

    1997-01-01

    This paper presents a new evolutionary system, i.e., EPNet, for evolving artificial neural networks (ANNs). The evolutionary algorithm used in EPNet is based on Fogel's evolutionary programming (EP). Unlike most previous studies on evolving ANN's, this paper puts its emphasis on evolving ANN's behaviors. Five mutation operators proposed in EPNet reflect such an emphasis on evolving behaviors. Close behavioral links between parents and their offspring are maintained by various mutations, such as partial training and node splitting. EPNet evolves ANN's architectures and connection weights (including biases) simultaneously in order to reduce the noise in fitness evaluation. The parsimony of evolved ANN's is encouraged by preferring node/connection deletion to addition. EPNet has been tested on a number of benchmark problems in machine learning and ANNs, such as the parity problem, the medical diagnosis problems, the Australian credit card assessment problem, and the Mackey-Glass time series prediction problem. The experimental results show that EPNet can produce very compact ANNs with good generalization ability in comparison with other algorithms.

  16. Reducing constraints on quantum computer design by encoded selective recoupling

    International Nuclear Information System (INIS)

    Lidar, D.A.; Wu, L.-A.

    2002-01-01

    The requirement of performing both single-qubit and two-qubit operations in the implementation of universal quantum logic often leads to very demanding constraints on quantum computer design. We show here how to eliminate the need for single-qubit operations in a large subset of quantum computer proposals: those governed by isotropic and XXZ , XY -type anisotropic exchange interactions. Our method employs an encoding of one logical qubit into two physical qubits, while logic operations are performed using an analogue of the NMR selective recoupling method

  17. Observational constraints on tachyonic chameleon dark energy model

    Science.gov (United States)

    Banijamali, A.; Bellucci, S.; Fazlpour, B.; Solbi, M.

    2018-03-01

    It has been recently shown that tachyonic chameleon model of dark energy in which tachyon scalar field non-minimally coupled to the matter admits stable scaling attractor solution that could give rise to the late-time accelerated expansion of the universe and hence alleviate the coincidence problem. In the present work, we use data from Type Ia supernova (SN Ia) and Baryon Acoustic oscillations to place constraints on the model parameters. In our analysis we consider in general exponential and non-exponential forms for the non-minimal coupling function and tachyonic potential and show that the scenario is compatible with observations.

  18. Forward pion-nucleon charge exchange reaction and Regge constraints

    International Nuclear Information System (INIS)

    Huang Fei; Sibirtsev, A.; Krewald, S.; Hanhart, C.; Haidenbauer, J.; Meibner, U.-G.

    2009-01-01

    We present our recent study of pion-nucleon charge exchange amplitudes above 2 GeV. We analyze the forward pion-nucleon charge exchange reaction data in a Regge model and compare the resulting amplitudes with those from the Karlsruhe-Helsinki and George-Washington-University partial-wave analyses. We explore possible high-energy constraints for theoretical baryon resonance analyses in the energy region above 2 GeV. Our results show that for the pion-nucleon charge exchange reaction, the appropriate energy region for matching meson-nucleon dynamics to diffractive scattering should be around 3 GeV for the helicity flip amplitude. (authors)

  19. Cosmological constraints on spontaneous R-symmetry breaking models

    Energy Technology Data Exchange (ETDEWEB)

    Hamada, Yuta; Kobayashi, Tatsuo [Kyoto Univ. (Japan). Dept. of Physics; Kamada, Kohei [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Ookouchi, Yutaka [Kyoto Univ. (Japan). Dept. of Physics; Kyoto Univ. (Japan). The Hakubi Center for Advanced Research and Dept. of Physics

    2012-11-15

    We study general constraints on spontaneous R-symmetry breaking models coming from the cosmological effects of the pseudo Nambu-Goldstone bosons, R-axions. They are substantially produced in the early Universe and may cause several cosmological problems. We focus on relatively long-lived R-axions and find that in a wide range of parameter space, models are severely constrained. In particular, R-axions with mass less than 1 MeV are generally ruled out for relatively high reheating temperature, T{sub R}>10 GeV.

  20. Studying the evolution of the hot universe with the X-ray evolving universe spectroscopy mission - XEUS

    DEFF Research Database (Denmark)

    Parmar, A.N.; Hasinger, G.; Arnaud, M.

    2004-01-01

    Europe is one of the major partners building the International Space Station (ISS) and European industry. together with ESA, is responsible for many station components including the Columbus Orbital Facility. the Automated Transport vehicle. two connecting modules and the European Robotic Arm...

  1. Optimal Stopping with Information Constraint

    International Nuclear Information System (INIS)

    Lempa, Jukka

    2012-01-01

    We study the optimal stopping problem proposed by Dupuis and Wang (Adv. Appl. Probab. 34:141–157, 2002). In this maximization problem of the expected present value of the exercise payoff, the underlying dynamics follow a linear diffusion. The decision maker is not allowed to stop at any time she chooses but rather on the jump times of an independent Poisson process. Dupuis and Wang (Adv. Appl. Probab. 34:141–157, 2002), solve this problem in the case where the underlying is a geometric Brownian motion and the payoff function is of American call option type. In the current study, we propose a mild set of conditions (covering the setup of Dupuis and Wang in Adv. Appl. Probab. 34:141–157, 2002) on both the underlying and the payoff and build and use a Markovian apparatus based on the Bellman principle of optimality to solve the problem under these conditions. We also discuss the interpretation of this model as optimal timing of an irreversible investment decision under an exogenous information constraint.

  2. Linear determining equations for differential constraints

    International Nuclear Information System (INIS)

    Kaptsov, O V

    1998-01-01

    A construction of differential constraints compatible with partial differential equations is considered. Certain linear determining equations with parameters are used to find such differential constraints. They generalize the classical determining equations used in the search for admissible Lie operators. As applications of this approach equations of an ideal incompressible fluid and non-linear heat equations are discussed

  3. Optimal Portfolio Choice with Wash Sale Constraints

    DEFF Research Database (Denmark)

    Astrup Jensen, Bjarne; Marekwica, Marcel

    2011-01-01

    We analytically solve the portfolio choice problem in the presence of wash sale constraints in a two-period model with one risky asset. Our results show that wash sale constraints can heavily affect portfolio choice of investors with unrealized losses. The trading behavior of such investors...

  4. Freedom and constraint analysis and optimization

    NARCIS (Netherlands)

    Brouwer, Dannis Michel; Boer, Steven; Aarts, Ronald G.K.M.; Meijaard, Jacob Philippus; Jonker, Jan B.

    2011-01-01

    Many mathematical and intuitive methods for constraint analysis of mechanisms have been proposed. In this article we compare three methods. Method one is based on Grüblers equation. Method two uses an intuitive analysis method based on opening kinematic loops and evaluating the constraints at the

  5. Network Design with Node Degree Balance Constraints

    DEFF Research Database (Denmark)

    Pedersen, Michael Berliner; Crainic, Teodor Gabriel

    This presentation discusses an extension to the network design model where there in addition to the flow conservation constraints also are constraints that require design conservation. This means that the number of arcs entering and leaving a node must be the same. As will be shown the model has ...

  6. Constraint solving for direct manipulation of features

    NARCIS (Netherlands)

    Lourenco, D.; Oliveira, P.; Noort, A.; Bidarra, R.

    2006-01-01

    In current commercial feature modeling systems, support for direct manipulation of features is not commonly available. This is partly due to the strong reliance of such systems on constraints, but also to the lack of speed of current constraint solvers. In this paper, an approach to the optimization

  7. A Temporal Concurrent Constraint Programming Calculus

    DEFF Research Database (Denmark)

    Palamidessi, Catuscia; Valencia Posso, Frank Darwin

    2001-01-01

    The tcc model is a formalism for reactive concurrent constraint programming. In this paper we propose a model of temporal concurrent constraint programming which adds to tcc the capability of modeling asynchronous and non-deterministic timed behavior. We call this tcc extension the ntcc calculus...

  8. Modifier constraints in alkali ultraphosphate glasses

    DEFF Research Database (Denmark)

    Rodrigues, B.P.; Mauro, J.C.; Yue, Yuanzheng

    2014-01-01

    In applying the recently introduced concept of cationic constraint strength [J. Chem. Phys. 140, 214501 (2014)] to bond constraint theory (BCT) of binary phosphate glasses in the ultraphosphate region of xR2O-(1-x)P2O5 (with x ≤ 0.5 and R = {Li, Na, Cs}), we demonstrate that a fundamental limitat...

  9. Specifying Dynamic and Deontic Integrity Constraints

    NARCIS (Netherlands)

    Wieringa, Roelf J.; Meyer, John-Jules; Weigand, Hans

    In the dominant view of knowledge bases (KB's), a KB is a set of facts (atomic sentences) and integrity constraints (IC's). An IC is then a sentence which must at least be consistent with the other sentences in the KB, This view obliterates the distinction between, for example, the constraint that

  10. Short-sale Constraints and Credit Runs

    DEFF Research Database (Denmark)

    Venter, Gyuri

    ), creditors with high private signals are more lenient to roll over debt, and a bank with lower asset quality remains solvent. This leads to higher allocative efficiency in the real economy. My result thus implies that the decrease in average informativeness due to short-sale constraints can be more than......This paper studies how short-sale constraints affect the informational efficiency of market prices and the link between prices and economic activity. I show that under short-sale constraints security prices contain less information. However, short-sale constraints increase the informativeness...... the price of an asset the bank holds. I show that short-selling constraints in the financial market lead to the revival of self-fulfilling beliefs about the beliefs and actions of others, and create multiple equilibria. In the equilibrium where agents rely more on public information (i.e., the price...

  11. Revisiting the simplicity constraints and coherent intertwiners

    International Nuclear Information System (INIS)

    Dupuis, Maite; Livine, Etera R

    2011-01-01

    In the context of loop quantum gravity and spinfoam models, the simplicity constraints are essential in that they allow one to write general relativity as a constrained topological BF theory. In this work, we apply the recently developed U(N) framework for SU(2) intertwiners to the issue of imposing the simplicity constraints to spin network states. More particularly, we focus on solving on individual intertwiners in the 4D Euclidean theory. We review the standard way of solving the simplicity constraints using coherent intertwiners and we explain how these fit within the U(N) framework. Then we show how these constraints can be written as a closed u(N) algebra and we propose a set of U(N) coherent states that solves all the simplicity constraints weakly for an arbitrary Immirzi parameter.

  12. canEvolve: a web portal for integrative oncogenomics.

    Directory of Open Access Journals (Sweden)

    Mehmet Kemal Samur

    Full Text Available BACKGROUND & OBJECTIVE: Genome-wide profiles of tumors obtained using functional genomics platforms are being deposited to the public repositories at an astronomical scale, as a result of focused efforts by individual laboratories and large projects such as the Cancer Genome Atlas (TCGA and the International Cancer Genome Consortium. Consequently, there is an urgent need for reliable tools that integrate and interpret these data in light of current knowledge and disseminate results to biomedical researchers in a user-friendly manner. We have built the canEvolve web portal to meet this need. RESULTS: canEvolve query functionalities are designed to fulfill most frequent analysis needs of cancer researchers with a view to generate novel hypotheses. canEvolve stores gene, microRNA (miRNA and protein expression profiles, copy number alterations for multiple cancer types, and protein-protein interaction information. canEvolve allows querying of results of primary analysis, integrative analysis and network analysis of oncogenomics data. The querying for primary analysis includes differential gene and miRNA expression as well as changes in gene copy number measured with SNP microarrays. canEvolve provides results of integrative analysis of gene expression profiles with copy number alterations and with miRNA profiles as well as generalized integrative analysis using gene set enrichment analysis. The network analysis capability includes storage and visualization of gene co-expression, inferred gene regulatory networks and protein-protein interaction information. Finally, canEvolve provides correlations between gene expression and clinical outcomes in terms of univariate survival analysis. CONCLUSION: At present canEvolve provides different types of information extracted from 90 cancer genomics studies comprising of more than 10,000 patients. The presence of multiple data types, novel integrative analysis for identifying regulators of oncogenesis, network

  13. Hamiltonian constraint in polymer parametrized field theory

    International Nuclear Information System (INIS)

    Laddha, Alok; Varadarajan, Madhavan

    2011-01-01

    Recently, a generally covariant reformulation of two-dimensional flat spacetime free scalar field theory known as parametrized field theory was quantized using loop quantum gravity (LQG) type ''polymer'' representations. Physical states were constructed, without intermediate regularization structures, by averaging over the group of gauge transformations generated by the constraints, the constraint algebra being a Lie algebra. We consider classically equivalent combinations of these constraints corresponding to a diffeomorphism and a Hamiltonian constraint, which, as in gravity, define a Dirac algebra. Our treatment of the quantum constraints parallels that of LQG and obtains the following results, expected to be of use in the construction of the quantum dynamics of LQG: (i) the (triangulated) Hamiltonian constraint acts only on vertices, its construction involves some of the same ambiguities as in LQG and its action on diffeomorphism invariant states admits a continuum limit, (ii) if the regulating holonomies are in representations tailored to the edge labels of the state, all previously obtained physical states lie in the kernel of the Hamiltonian constraint, (iii) the commutator of two (density weight 1) Hamiltonian constraints as well as the operator correspondent of their classical Poisson bracket converge to zero in the continuum limit defined by diffeomorphism invariant states, and vanish on the Lewandowski-Marolf habitat, (iv) the rescaled density 2 Hamiltonian constraints and their commutator are ill-defined on the Lewandowski-Marolf habitat despite the well-definedness of the operator correspondent of their classical Poisson bracket there, (v) there is a new habitat which supports a nontrivial representation of the Poisson-Lie algebra of density 2 constraints.

  14. Long-Term Environmental Research Programs - Evolving Capacity for Discovery

    Science.gov (United States)

    Swanson, F. J.

    2008-12-01

    Long-term forestry, watershed, and ecological research sites have become critical, productive nodes for environmental science research and in some cases for work in the social sciences and humanities. The Forest Service's century-old Experimental Forests and Ranges and the National Science Foundation's 28- year-old Long-Term Ecological Research program have been remarkably productive in both basic and applied sciences, including characterization of acid rain and old-growth ecosystems and development of forest, watershed, and range management systems for commercial and other land use objectives. A review of recent developments suggests steps to enhance the function of collections of long-term research sites as interactive science networks. The programs at these sites have evolved greatly, especially over the past few decades, as the questions addressed, disciplines engaged, and degree of science integration have grown. This is well displayed by small, experimental watershed studies, which first were used for applied hydrology studies then more fundamental biogeochemical studies and now examination of complex ecosystem processes; all capitalizing on the legacy of intensive studies and environmental monitoring spanning decades. In very modest ways these collections of initially independent sites have functioned increasingly as integrated research networks addressing inter-site questions by using common experimental designs, being part of a single experiment, and examining long-term data in a common analytical framework. The network aspects include data sharing via publicly-accessible data-harvester systems for climate and streamflow data. The layering of one research or environmental monitoring network upon another facilitates synergies. Changing climate and atmospheric chemistry highlight a need to use these networks as continental-scale observatory systems for assessing the impacts of environmental change on ecological services. To better capitalize on long

  15. Coordinated Control of Wave Energy Converters Subject to Motion Constraints

    Directory of Open Access Journals (Sweden)

    Liguo Wang

    2016-06-01

    Full Text Available In this paper, a generic coordinated control method for wave energy converters is proposed, and the constraints on motion amplitudes and the hydrodynamic interaction between converters are considered. The objective of the control problem is to maximize the energy converted from ocean waves, and this is achieved by coordinating the power take-off (PTO damping of each wave energy converter in the frequency domain in each sea state. In a case study, a wave energy farm consisting of four converters based on the concept developed by Uppsala University is studied. In the solution, motion constraints, including constraints on the amplitudes of displacement and velocity, are included. Twelve months of sea states, based on measured wave data at the Lysekil test site on the Swedish west coast, are used in the simulation to evaluate the performance of the wave energy farm using the new method. Results from the new coordinated control method and traditional control method are compared, indicating that the coordinated control of wave energy converters is an effective way to improve the energy production of wave energy farm in harmonic waves.

  16. LHC constraints on Yukawa unification in SO(10)

    Energy Technology Data Exchange (ETDEWEB)

    Badziak, Marcin [Cambridge Univ. (United Kingdom). Centre for Mathematical Sciences; Cambridge Univ. (United Kingdom). Cavendish Lab.; Sakurai, Kazuki [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2011-12-15

    LHC constraints on the recently proposed SUSY SO(10) GUT model with top-bottom-tau Yukawa uni cation are investigated. In this model, various phenomenological constraints are in concord with Yukawa uni cation thanks to the negative sign of {mu}, D-term splitting in the soft scalar masses and non-universal gaugino masses generated by non-zero F-term in a 24-dimensional representation of SU(5) is contained in SO(10). After discussing the impact of the CP-odd Higgs boson mass bound on this model, we provide a detailed analysis of the recent direct SUSY searches performed by ATLAS and investigate the constraints on this SO(10) model. At 95% confidence level, the lower limit on the gluino mass is found at 675 GeV. Assuming an integrated luminosity of 10 fb{sup -1}, this bound may be extended to 1.1 TeV if the right-handed down squark is lighter than about 1 TeV. (orig.)

  17. Five fundamental constraints on theories of the origins of music.

    Science.gov (United States)

    Merker, Bjorn; Morley, Iain; Zuidema, Willem

    2015-03-19

    The diverse forms and functions of human music place obstacles in the way of an evolutionary reconstruction of its origins. In the absence of any obvious homologues of human music among our closest primate relatives, theorizing about its origins, in order to make progress, needs constraints from the nature of music, the capacities it engages, and the contexts in which it occurs. Here we propose and examine five fundamental constraints that bear on theories of how music and some of its features may have originated. First, cultural transmission, bringing the formal powers of cultural as contrasted with Darwinian evolution to bear on its contents. Second, generativity, i.e. the fact that music generates infinite pattern diversity by finite means. Third, vocal production learning, without which there can be no human singing. Fourth, entrainment with perfect synchrony, without which there is neither rhythmic ensemble music nor rhythmic dancing to music. And fifth, the universal propensity of humans to gather occasionally to sing and dance together in a group, which suggests a motivational basis endemic to our biology. We end by considering the evolutionary context within which these constraints had to be met in the genesis of human musicality. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  18. Sport participation of female university students | Nxumalo | South ...

    African Journals Online (AJOL)

    South African Journal for Research in Sport, Physical Education and Recreation ... The main reasons for non-participation were: 'no time' (68%), transport problems (8%) ... The university management should address the constraints to promote ...

  19. Supersymmetric Grand Unification and Lepton Universality in $K \\to l\

    CERN Document Server

    Ellis, Jonathan Richard; Raidal, Martti

    2009-01-01

    in the near future, one may nevertheless obtain significant constraints on the model parameters and unknown aspects of right-handed fermion and sfermion mixing. Motivated by the prospects for an improved test of lepton universality in K -> l \

  20. New constraints on variations of the fine structure constant from CMB anisotropies

    International Nuclear Information System (INIS)

    Menegoni, Eloisa; Melchiorri, Alessandro; Galli, Silvia; Bartlett, James G.; Martins, C. J. A. P.

    2009-01-01

    We demonstrate that recent measurements of cosmic microwave background temperature and polarization anisotropy made by the ACBAR, QUAD, and BICEP experiments substantially improve the cosmological constraints on possible variations of the fine structure constant in the early universe. This data, combined with the five year observations from the WMAP mission, yield the constraint α/α 0 =0.987±0.012 at 68% C.L. The inclusion of the new Hubble Space Telescope constraints on the Hubble constant further increases the accuracy to α/α 0 =1.001±0.007 at 68% C.L., bringing possible deviations from the current value below the 1% level and improving previous constraints by a factor of ∼3.

  1. Interpreting the universal phylogenetic tree

    Science.gov (United States)

    Woese, C. R.

    2000-01-01

    The universal phylogenetic tree not only spans all extant life, but its root and earliest branchings represent stages in the evolutionary process before modern cell types had come into being. The evolution of the cell is an interplay between vertically derived and horizontally acquired variation. Primitive cellular entities were necessarily simpler and more modular in design than are modern cells. Consequently, horizontal gene transfer early on was pervasive, dominating the evolutionary dynamic. The root of the universal phylogenetic tree represents the first stage in cellular evolution when the evolving cell became sufficiently integrated and stable to the erosive effects of horizontal gene transfer that true organismal lineages could exist.

  2. Few-body hypernuclear constraints

    International Nuclear Information System (INIS)

    Gibson, B.F.

    1993-01-01

    Since the discovery of the first hyperfragment in a balloon flown emulsion stack some two score years ago, physicists have worked to understand how the addition of the strangeness degree of freedom alters the picture of nuclei and the baryon-baryon force. Because the Λ and Σ masses differ markedly from that of the proton and neutron, SU (3) symmetry is broken. How it is broken is a question of importance to the fundamental understanding of the baryon-baryon interaction. New dynamical symmetries, forbidden by the Pauli principle in conventional nuclei, appear. Three-body forces play a more significant role. A binding anomaly in A = 5 as well as a possible spin inversion between ground and excited states in A = 4 appear. Surprisingly narrow structure near the threshold for Σ production has been reported in the 4 He (K - , π - ) spectrum while no corresponding structure is observed in the companion 4 He(K - , π + ) spectrum; this has been interpreted as evidence for a Σ 4 He bound state. Finally, the reported observation of ΛΛ-hypernuclei, in particular ΛΛ 6 He, bears directly upon the possibilities for the prediction of a bound H particle--the S = -2 dibaryon. Although it is not feasible to invert the analysis and determine the interaction from the data on few-body systems, it is possible to utilize these data to constrain the models, provided one is careful. The author will explore briefly the constraints which the few-body data impose and the level of understanding that has been achieved

  3. Cosmological constraints on exotic injection of electromagnetic energy

    Energy Technology Data Exchange (ETDEWEB)

    Poulin, Vivian; Serpico, Pasquale D. [LAPTh, Université Savoie Mont Blanc and CNRS, 9 Chemin de Bellevue BP 110 Annecy-le-Vieux F-74941 Annecy Cedex (France); Lesgourgues, Julien, E-mail: Vivian.Poulin@lapth.cnrs.fr, E-mail: Pasquale.Serpico@lapth.cnrs.fr, E-mail: Julien.Lesgourgues@physik.rwth-aachen.de [Institute for Theoretical Particle Physics and Cosmology (TTK), RWTH Aachen University, D-52056 Aachen (Germany)

    2017-03-01

    We compute cosmic microwave background (CMB) anisotropy constraints on exotic forms of energy injection in electromagnetic (e.m.) channels over a large range of timescales. We show that these constraints are very powerful around or just after recombination, although CMB keeps some sensitivity e.g. to decaying species with lifetimes as long as 10{sup 25} s. These bounds are complementary to CMB spectral distortions and primordial nucleosynthesis ones, which dominate at earlier timescales, as we also review here. For the first time, we describe the effects of the e.m. energy injection on the CMB power spectra as a function of the injection epoch , using the lifetime of a decaying particle as proxy. We also identify a suitable on-the-spot approximation, that can be used to derive accurate constraints, and describe its differences with the most up-to-date treatment. Our results are of interest not only for early universe relics constituting (a fraction of) the dark matter, but also for other exotic injection of e.m. radiation. For illustration, we apply our formalism to: i) Primordial black holes of mass 10{sup 13.5} g ∼< M ∼< 10{sup 16.8} g, showing that the constraints are comparable to the ones obtained from gamma-ray background studies and even dominate below ∼ 10{sup 14} g. ii) To a peculiar mass-mixing range in the sterile neutrino parameter space, complementary to other astrophysical and laboratory probes. iii) Finally, we provide a first estimate of the room for improvement left for forthcoming 21 cm experiments, comparing it with the reach of proposed CMB spectral distortion (PiXiE) and CMB angular power spectrum (CORE) missions. We show that the best and most realistic opportunity to look for this signal (or to improve over current constraints) in the 21 cm probe is to focus on the Cosmic Dawn epoch, 15 ∼< z ∼< 30, where the qualitatively unambiguous signature of a spectrum in emission can be expected for models that evade all current constraints.

  4. Astronomy in the Digital Universe

    Science.gov (United States)

    Haisch, Bernard M.; Lindblom, J.; Terzian, Y.

    2006-12-01

    The Digital Universe is an Internet project whose mission is to provide free, accurate, unbiased information covering all aspects of human knowledge, and to inspire humans to learn, make use of, and expand this knowledge. It is planned to be a decades long effort, inspired by the Encyclopedia Galactica concept popularized by Carl Sagan, and is being developed by the non-profit Digital Universe Foundation. A worldwide network of experts is responsible for selecting content featured within the Digital Universe. The first publicly available content is the Encyclopedia of Earth, a Boston University project headed by Prof. Cutler Cleveland, which will be part of the Earth Portal. The second major content area will be an analogous Encyclopedia of the Cosmos to be part of the Cosmos Portal. It is anticipated that this will evolve into a major resource for astronomy education. Authors and topic editors are now being recruited for the Encyclopedia of the Cosmos.

  5. Modeling and clustering users with evolving profiles in usage streams

    KAUST Repository

    Zhang, Chongsheng

    2012-09-01

    Today, there is an increasing need of data stream mining technology to discover important patterns on the fly. Existing data stream models and algorithms commonly assume that users\\' records or profiles in data streams will not be updated or revised once they arrive. Nevertheless, in various applications such asWeb usage, the records/profiles of the users can evolve along time. This kind of streaming data evolves in two forms, the streaming of tuples or transactions as in the case of traditional data streams, and more importantly, the evolving of user records/profiles inside the streams. Such data streams bring difficulties on modeling and clustering for exploring users\\' behaviors. In this paper, we propose three models to summarize this kind of data streams, which are the batch model, the Evolving Objects (EO) model and the Dynamic Data Stream (DDS) model. Through creating, updating and deleting user profiles, these models summarize the behaviors of each user as a profile object. Based upon these models, clustering algorithms are employed to discover interesting user groups from the profile objects. We have evaluated all the proposed models on a large real-world data set, showing that the DDS model summarizes the data streams with evolving tuples more efficiently and effectively, and provides better basis for clustering users than the other two models. © 2012 IEEE.

  6. Modeling and clustering users with evolving profiles in usage streams

    KAUST Repository

    Zhang, Chongsheng; Masseglia, Florent; Zhang, Xiangliang

    2012-01-01

    Today, there is an increasing need of data stream mining technology to discover important patterns on the fly. Existing data stream models and algorithms commonly assume that users' records or profiles in data streams will not be updated or revised once they arrive. Nevertheless, in various applications such asWeb usage, the records/profiles of the users can evolve along time. This kind of streaming data evolves in two forms, the streaming of tuples or transactions as in the case of traditional data streams, and more importantly, the evolving of user records/profiles inside the streams. Such data streams bring difficulties on modeling and clustering for exploring users' behaviors. In this paper, we propose three models to summarize this kind of data streams, which are the batch model, the Evolving Objects (EO) model and the Dynamic Data Stream (DDS) model. Through creating, updating and deleting user profiles, these models summarize the behaviors of each user as a profile object. Based upon these models, clustering algorithms are employed to discover interesting user groups from the profile objects. We have evaluated all the proposed models on a large real-world data set, showing that the DDS model summarizes the data streams with evolving tuples more efficiently and effectively, and provides better basis for clustering users than the other two models. © 2012 IEEE.

  7. Rational Constraints and the Evolution of Fairness in the Ultimatum Game.

    Science.gov (United States)

    Tomlin, Damon

    2015-01-01

    Behavior in the Ultimatum Game has been well-studied experimentally, and provides a marked contrast between the theoretical model of a self-interested economic agent and that of an actual human concerned with social norms such as fairness. How did such norms evolve, when punishing unfair behavior can be costly to the punishing agent? The work described here simulated a series of Ultimatum Games, in which populations of agents earned resources based on their preferences for proposing and accepting (or rejecting) offers of various sizes. Two different systems governing the acceptance or rejection of offers were implemented. Under one system, the probability that an agent accepted an offer of a given size was independent of the probabilities of accepting the other possible offers. Under the other system, a simple, ordinal constraint was placed on the acceptance probabilities such that a given offer was at least as likely to be accepted as a smaller offer. For simulations under either system, agents' preferences and their corresponding behavior evolved over multiple generations. Populations without the ordinal constraint came to emulate maximizing economic agents, while populations with the constraint came to resemble the behavior of human players.

  8. Fractal geometry in an expanding, one-dimensional, Newtonian universe.

    Science.gov (United States)

    Miller, Bruce N; Rouet, Jean-Louis; Le Guirriec, Emmanuel

    2007-09-01

    Observations of galaxies over large distances reveal the possibility of a fractal distribution of their positions. The source of fractal behavior is the lack of a length scale in the two body gravitational interaction. However, even with new, larger, sample sizes from recent surveys, it is difficult to extract information concerning fractal properties with confidence. Similarly, three-dimensional N-body simulations with a billion particles only provide a thousand particles per dimension, far too small for accurate conclusions. With one-dimensional models these limitations can be overcome by carrying out simulations with on the order of a quarter of a million particles without compromising the computation of the gravitational force. Here the multifractal properties of two of these models that incorporate different features of the dynamical equations governing the evolution of a matter dominated universe are compared. For each model at least two scaling regions are identified. By employing criteria from dynamical systems theory it is shown that only one of them can be geometrically significant. The results share important similarities with galaxy observations, such as hierarchical clustering and apparent bifractal geometry. They also provide insights concerning possible constraints on length and time scales for fractal structure. They clearly demonstrate that fractal geometry evolves in the mu (position, velocity) space. The observed patterns are simply a shadow (projection) of higher-dimensional structure.

  9. Constraint Handling Rules with Binders, Patterns and Generic Quantification

    NARCIS (Netherlands)

    Serrano, Alejandro; Hage, J.

    2017-01-01

    Constraint Handling Rules provide descriptions for constraint solvers. However, they fall short when those constraints specify some binding structure, like higher-rank types in a constraint-based type inference algorithm. In this paper, the term syntax of constraints is replaced by λ-tree syntax, in

  10. Galaxy clustering and small-scale CBR anisotropy constraints on galaxy origin scenarios

    International Nuclear Information System (INIS)

    Lucchin, F.

    1986-01-01

    The problem of the origin of cosmic structures (galaxies, galaxy clusters,......) represents the crossroads of the modern cosmology: it is correlated both with the theoretical model of the very early universe and with most of the present observational data. In this context, galaxy origin scenarios are reviewed. The cosmological relevance of the observed clustering properties of the universe is outlined. The observational constraints, due to small-scale cosmic background radiation (CBR) anisotropies, on galaxy origin scenarios are discussed. (author)

  11. Universe symmetries

    International Nuclear Information System (INIS)

    Souriau, J.M.

    1984-01-01

    The sky uniformity can be noticed in studying the repartition of objects far enough. The sky isotropy description uses space rotations. The group theory elements will allow to give a meaning at the same time precise and general to the word a ''symmetry''. Universe models are reviewed, which must have both of the following qualities: - conformity with the physic known laws; - rigorous symmetry following one of the permitted groups. Each of the models foresees that universe evolution obeys an evolution equation. Expansion and big-bang theory are recalled. Is universe an open or closed space. Universe is also electrically neutral. That leads to a work hypothesis: the existing matter is not given data of universe but it appeared by evolution from nothing. Problem of matter and antimatter is then raised up together with its place in universe [fr

  12. QCD unitarity constraints on Reggeon Field Theory

    Energy Technology Data Exchange (ETDEWEB)

    Kovner, Alex [Physics Department, University of Connecticut,2152 Hillside Road, Storrs, CT 06269 (United States); Levin, Eugene [Departemento de Física, Universidad Técnica Federico Santa María,and Centro Científico-Tecnológico de Valparaíso,Avda. Espana 1680, Casilla 110-V, Valparaíso (Chile); Department of Particle Physics, Tel Aviv University,Tel Aviv 69978 (Israel); Lublinsky, Michael [Physics Department, Ben-Gurion University of the Negev,Beer Sheva 84105 (Israel); Physics Department, University of Connecticut,2152 Hillside Road, Storrs, CT 06269 (United States)

    2016-08-04

    We point out that the s-channel unitarity of QCD imposes meaningful constraints on a possible form of the QCD Reggeon Field Theory. We show that neither the BFKL nor JIMWLK nor Braun’s Hamiltonian satisfy the said constraints. In a toy, zero transverse dimensional case we construct a model that satisfies the analogous constraint and show that at infinite energy it indeed tends to a “black disk limit' as opposed to the model with triple Pomeron vertex only, routinely used as a toy model in the literature.

  13. QCD unitarity constraints on Reggeon Field Theory

    International Nuclear Information System (INIS)

    Kovner, Alex; Levin, Eugene; Lublinsky, Michael

    2016-01-01

    We point out that the s-channel unitarity of QCD imposes meaningful constraints on a possible form of the QCD Reggeon Field Theory. We show that neither the BFKL nor JIMWLK nor Braun’s Hamiltonian satisfy the said constraints. In a toy, zero transverse dimensional case we construct a model that satisfies the analogous constraint and show that at infinite energy it indeed tends to a “black disk limit' as opposed to the model with triple Pomeron vertex only, routinely used as a toy model in the literature.

  14. Liquidity Constraints and Fiscal Stabilization Policy

    DEFF Research Database (Denmark)

    Kristoffersen, Mark Strøm

    It is often claimed that the presence of liquidity constrained households enhances the need for and the effects of fi…scal stabilization policies. This paper studies this in a model of a small open economy with liquidity constrained households. The results show that the consequences of liquidity...... constraints are more complex than previously thought: The optimal stabilization policy in case of productivity shocks is independent of the liquidity constraints, and the presence of liquidity constraints tends to reduce the need for an active policy stabilizing productivity shocks....

  15. Use of dose constraints for occupational exposure

    International Nuclear Information System (INIS)

    Kaijage, Tunu

    2015-02-01

    The use of dose constraints for occupational exposure was reviewed in this project. The role of dose constraints as used in optimization of protection of workers was described. Different issues to be considered in application of the concept and challenges associated with their implementation were also discussed. The situation where dose constraints could be misinterpreted to dose limits is also explained as the two are clearly differentiated by the International Commission of Radiological Protection (ICRP) Publication 103. Moreover, recommendations to all parties responsible for protection and safety of workers were discussed. (au)

  16. Constraint satisfaction problems CSP formalisms and techniques

    CERN Document Server

    Ghedira, Khaled

    2013-01-01

    A Constraint Satisfaction Problem (CSP) consists of a set of variables, a domain of values for each variable and a set of constraints. The objective is to assign a value for each variable such that all constraints are satisfied. CSPs continue to receive increased attention because of both their high complexity and their omnipresence in academic, industrial and even real-life problems. This is why they are the subject of intense research in both artificial intelligence and operations research. This book introduces the classic CSP and details several extensions/improvements of both formalisms a

  17. Expressing Model Constraints Visually with VMQL

    DEFF Research Database (Denmark)

    Störrle, Harald

    2011-01-01

    ) for specifying constraints on UML models. We examine VMQL's usability by controlled experiments and its expressiveness by a representative sample. We conclude that VMQL is less expressive than OCL, although expressive enough for most of the constraints in the sample. In terms of usability, however, VMQL......OCL is the de facto standard language for expressing constraints and queries on UML models. However, OCL expressions are very difficult to create, understand, and maintain, even with the sophisticated tool support now available. In this paper, we propose to use the Visual Model Query Language (VMQL...

  18. Cosmological constraints from Chandra observations of galaxy clusters.

    Science.gov (United States)

    Allen, Steven W

    2002-09-15

    Chandra observations of rich, relaxed galaxy clusters allow the properties of the X-ray gas and the total gravitating mass to be determined precisely. Here, we present results for a sample of the most X-ray luminous, dynamically relaxed clusters known. We show that the Chandra data and independent gravitational lensing studies provide consistent answers on the mass distributions in the clusters. The mass profiles exhibit a form in good agreement with the predictions from numerical simulations. Combining Chandra results on the X-ray gas mass fractions in the clusters with independent measurements of the Hubble constant and the mean baryonic matter density in the Universe, we obtain a tight constraint on the mean total matter density of the Universe, Omega(m), and an interesting constraint on the cosmological constant, Omega(Lambda). We also describe the 'virial relations' linking the masses, X-ray temperatures and luminosities of galaxy clusters. These relations provide a key step in linking the observed number density and spatial distribution of clusters to the predictions from cosmological models. The Chandra data confirm the presence of a systematic offset of ca. 40% between the normalization of the observed mass-temperature relation and the predictions from standard simulations. This finding leads to a significant revision of the best-fit value of sigma(8) inferred from the observed temperature and luminosity functions of clusters.

  19. When clusters collide: constraints on antimatter on the largest scales

    International Nuclear Information System (INIS)

    Steigman, Gary

    2008-01-01

    Observations have ruled out the presence of significant amounts of antimatter in the Universe on scales ranging from the solar system, to the Galaxy, to groups and clusters of galaxies, and even to distances comparable to the scale of the present horizon. Except for the model-dependent constraints on the largest scales, the most significant upper limits to diffuse antimatter in the Universe are those on the ∼Mpc scale of clusters of galaxies provided by the EGRET upper bounds to annihilation gamma rays from galaxy clusters whose intracluster gas is revealed through its x-ray emission. On the scale of individual clusters of galaxies the upper bounds to the fraction of mixed matter and antimatter for the 55 clusters from a flux-limited x-ray survey range from 5 × 10 −9 to −6 , strongly suggesting that individual clusters of galaxies are made entirely of matter or of antimatter. X-ray and gamma-ray observations of colliding clusters of galaxies, such as the Bullet Cluster, permit these constraints to be extended to even larger scales. If the observations of the Bullet Cluster, where the upper bound to the antimatter fraction is found to be −6 , can be generalized to other colliding clusters of galaxies, cosmologically significant amounts of antimatter will be excluded on scales of order ∼20 Mpc (M∼5×10 15 M sun )

  20. Constraint-Based Abstraction of a Model Checker for Infinite State Systems

    DEFF Research Database (Denmark)

    Banda, Gourinath; Gallagher, John Patrick

    Abstract interpretation-based model checking provides an approach to verifying properties of infinite-state systems. In practice, most previous work on abstract model checking is either restricted to verifying universal properties, or develops special techniques for temporal logics such as modal t...... to implementation of abstract model checking algorithms for abstract domains based on constraints, making use of an SMT solver....

  1. Evidence for the Fundamental Difference Hypothesis or Not?: Island Constraints Revisited

    Science.gov (United States)

    Belikova, Alyona; White, Lydia

    2009-01-01

    This article examines how changes in linguistic theory affect the debate between the fundamental difference hypothesis and the access-to-Universal Grammar (UG) approach to SLA. With a focus on subjacency (Chomsky, 1973), a principle of UG that places constraints on "wh"-movement and that has frequently been taken as a test case for verifying…

  2. Education for Development in Northern Pakistan: Opportunities and Constraints for Rural Households

    Directory of Open Access Journals (Sweden)

    Emma Varley

    2015-11-01

    Full Text Available Reviewed: Education for Development in Northern Pakistan: Opportunities and Constraints for Rural Households By Andreas Benz. Karachi, Pakistan: Oxford University Press, 2014. xxxii + 434 pp. PKR 1850.00, € 27.99, US$ 45.00. ISBN 978-0-19-906917-0.

  3. Higher Education Decisions in Peru: On the Role of Financial Constraints, Skills, and Family Background

    Science.gov (United States)

    Castro, Juan F.; Yamada, Gustavo; Arias, Omar

    2016-01-01

    This paper analyzes the relative importance of short-term financial constraints "vis-a-vis" skills and other background factors when explaining higher education access in Peru. We focus on the disparities in university enrollment between rich and poor households. We use a novel household survey that includes special tests to measure…

  4. Creating and Using a Computer Networking and Systems Administration Laboratory Built under Relaxed Financial Constraints

    Science.gov (United States)

    Conlon, Michael P.; Mullins, Paul

    2011-01-01

    The Computer Science Department at Slippery Rock University created a laboratory for its Computer Networks and System Administration and Security courses under relaxed financial constraints. This paper describes the department's experience designing and using this laboratory, including lessons learned and descriptions of some student projects…

  5. FY1995 evolvable hardware chip; 1995 nendo shinkasuru hardware chip

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    This project aims at the development of 'Evolvable Hardware' (EHW) which can adapt its hardware structure to the environment to attain better hardware performance, under the control of genetic algorithms. EHW is a key technology to explore the new application area requiring real-time performance and on-line adaptation. 1. Development of EHW-LSI for function level hardware evolution, which includes 15 DSPs in one chip. 2. Application of the EHW to the practical industrial applications such as data compression, ATM control, digital mobile communication. 3. Two patents : (1) the architecture and the processing method for programmable EHW-LSI. (2) The method of data compression for loss-less data, using EHW. 4. The first international conference for evolvable hardware was held by authors: Intl. Conf. on Evolvable Systems (ICES96). It was determined at ICES96 that ICES will be held every two years between Japan and Europe. So the new society has been established by us. (NEDO)

  6. Evolving Systems: An Outcome of Fondest Hopes and Wildest Dreams

    Science.gov (United States)

    Frost, Susan A.; Balas, Mark J.

    2012-01-01

    New theory is presented for evolving systems, which are autonomously controlled subsystems that self-assemble into a new evolved system with a higher purpose. Evolving systems of aerospace structures often require additional control when assembling to maintain stability during the entire evolution process. This is the concept of Adaptive Key Component Control that operates through one specific component to maintain stability during the evolution. In addition, this control must often overcome persistent disturbances that occur while the evolution is in progress. Theoretical results will be presented for Adaptive Key Component control for persistent disturbance rejection. An illustrative example will demonstrate the Adaptive Key Component controller on a system composed of rigid body and flexible body modes.

  7. Qualitative Functional Decomposition Analysis of Evolved Neuromorphic Flight Controllers

    Directory of Open Access Journals (Sweden)

    Sanjay K. Boddhu

    2012-01-01

    Full Text Available In the previous work, it was demonstrated that one can effectively employ CTRNN-EH (a neuromorphic variant of EH method methodology to evolve neuromorphic flight controllers for a flapping wing robot. This paper describes a novel frequency grouping-based analysis technique, developed to qualitatively decompose the evolved controllers into explainable functional control blocks. A summary of the previous work related to evolving flight controllers for two categories of the controller types, called autonomous and nonautonomous controllers, is provided, and the applicability of the newly developed decomposition analysis for both controller categories is demonstrated. Further, the paper concludes with appropriate discussion of ongoing work and implications for possible future work related to employing the CTRNN-EH methodology and the decomposition analysis techniques presented in this paper.

  8. Cosmic Biology How Life Could Evolve on Other Worlds

    CERN Document Server

    Irwin, Louis Neil

    2011-01-01

    It is very unlikely that little green humanoids are living on Mars. But what are the possible life forms that might exist in our Solar System and how might they have evolved? This uniquely authoritative and imaginative book on the possibilties for alien life addresses the intrinsic interest that we have about life on other worlds - reinforcing some of our assumptions and reshaping others. It introduces new possibilties that will enlarge our understanding of the issue overall, in particular the enormous range of environments and planetary conditions within which life might evolve. Cosmic Biology -discusses a broad range of possible environments where alien life might have evolved; -explains why carbon-based, water-borne life is more likely that its alternatives, but is not the only possiblity; -applies the principles of planetary science and modern biology to evolutionary scenarios on other worlds; -looks at the future fates of living systems, including those on Earth.

  9. Computational Genetic Regulatory Networks Evolvable, Self-organizing Systems

    CERN Document Server

    Knabe, Johannes F

    2013-01-01

    Genetic Regulatory Networks (GRNs) in biological organisms are primary engines for cells to enact their engagements with environments, via incessant, continually active coupling. In differentiated multicellular organisms, tremendous complexity has arisen in the course of evolution of life on earth. Engineering and science have so far achieved no working system that can compare with this complexity, depth and scope of organization. Abstracting the dynamics of genetic regulatory control to a computational framework in which artificial GRNs in artificial simulated cells differentiate while connected in a changing topology, it is possible to apply Darwinian evolution in silico to study the capacity of such developmental/differentiated GRNs to evolve. In this volume an evolutionary GRN paradigm is investigated for its evolvability and robustness in models of biological clocks, in simple differentiated multicellularity, and in evolving artificial developing 'organisms' which grow and express an ontogeny starting fr...

  10. The Evolving Role of Physicians - Don't Forget the Generalist Primary Care Providers Comment on "Non-physician Clinicians in Sub-Saharan Africa and the Evolving Role of Physicians".

    Science.gov (United States)

    Cubaka, Vincent Kalumire; Schriver, Michael; Flinkenflögel, Maaike; Cotton, Philip

    2016-06-12

    The editorial "Non-physician Clinicians in Sub-Saharan Africa and the Evolving Role of Physicians" by Eyal et al describes non-physician clinicians' (NPC) need for mentorship and support from physicians. We emphasise the same need of support for front line generalist primary healthcare providers who carry out complex tasks yet may have an inadequate skill mix. © 2016 by Kerman University of Medical Sciences.

  11. Dose constraints, what are they now?

    International Nuclear Information System (INIS)

    Lazo, T.

    2005-01-01

    The concept of a source-related dose constraint was first introduced in ICPR publication 60. The idea was to provide a number that individual exposures from a single, specific source should not exceed, and below which optimisation of protection should take place. Dose constraints were applied to occupational and public exposures from practices. In order to simplify and clarify the ICRP's recommendations, the latest draft, RPO5, presents dose constraints again, and with the same meaning as in publication 60. However, the dose constraints are now applied in all situations, not just practices. This new approach does provide simplification, in that a single concept is applied to all types of exposures (normal situations, accident situations, and existing situations). However, the approach and numerical values that are selected by regulatory authorities for the application of the concept, particularly in normal situations which are also subject to dose limits, will be crucial to the implementation of the system of radiological protection. (author)

  12. Biological constraints do not entail cognitive closure.

    Science.gov (United States)

    Vlerick, Michael

    2014-12-01

    From the premise that our biology imposes cognitive constraints on our epistemic activities, a series of prominent authors--most notably Fodor, Chomsky and McGinn--have argued that we are cognitively closed to certain aspects and properties of the world. Cognitive constraints, they argue, entail cognitive closure. I argue that this is not the case. More precisely, I detect two unwarranted conflations at the core of arguments deriving closure from constraints. The first is a conflation of what I will refer to as 'representation' and 'object of representation'. The second confuses the cognitive scope of the assisted mind for that of the unassisted mind. Cognitive closure, I conclude, cannot be established from pointing out the (uncontroversial) existence of cognitive constraints. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. institutional and resource constraints that inhibit contractor ...

    African Journals Online (AJOL)

    p2333147

    Keywords: Institutions; small-scale contractor performance; sugar industry. ABSTRACT ..... diverse cultural settings, women, specifically widowed or single women, have a .... constraints on business growth, such as the work limitations placed.

  14. Constraint theory multidimensional mathematical model management

    CERN Document Server

    Friedman, George J

    2017-01-01

    Packed with new material and research, this second edition of George Friedman’s bestselling Constraint Theory remains an invaluable reference for all engineers, mathematicians, and managers concerned with modeling. As in the first edition, this text analyzes the way Constraint Theory employs bipartite graphs and presents the process of locating the “kernel of constraint” trillions of times faster than brute-force approaches, determining model consistency and computational allowability. Unique in its abundance of topological pictures of the material, this book balances left- and right-brain perceptions to provide a thorough explanation of multidimensional mathematical models. Much of the extended material in this new edition also comes from Phan Phan’s PhD dissertation in 2011, titled “Expanding Constraint Theory to Determine Well-Posedness of Large Mathematical Models.” Praise for the first edition: "Dr. George Friedman is indisputably the father of the very powerful methods of constraint theory...

  15. Route constraints model based on polychromatic sets

    Science.gov (United States)

    Yin, Xianjun; Cai, Chao; Wang, Houjun; Li, Dongwu

    2018-03-01

    With the development of unmanned aerial vehicle (UAV) technology, the fields of its application are constantly expanding. The mission planning of UAV is especially important, and the planning result directly influences whether the UAV can accomplish the task. In order to make the results of mission planning for unmanned aerial vehicle more realistic, it is necessary to consider not only the physical properties of the aircraft, but also the constraints among the various equipment on the UAV. However, constraints among the equipment of UAV are complex, and the equipment has strong diversity and variability, which makes these constraints difficult to be described. In order to solve the above problem, this paper, referring to the polychromatic sets theory used in the advanced manufacturing field to describe complex systems, presents a mission constraint model of UAV based on polychromatic sets.

  16. Constraint-based Attribute and Interval Planning

    Science.gov (United States)

    Jonsson, Ari; Frank, Jeremy

    2013-01-01

    In this paper we describe Constraint-based Attribute and Interval Planning (CAIP), a paradigm for representing and reasoning about plans. The paradigm enables the description of planning domains with time, resources, concurrent activities, mutual exclusions among sets of activities, disjunctive preconditions and conditional effects. We provide a theoretical foundation for the paradigm, based on temporal intervals and attributes. We then show how the plans are naturally expressed by networks of constraints, and show that the process of planning maps directly to dynamic constraint reasoning. In addition, we de ne compatibilities, a compact mechanism for describing planning domains. We describe how this framework can incorporate the use of constraint reasoning technology to improve planning. Finally, we describe EUROPA, an implementation of the CAIP framework.

  17. Automated constraint placement to maintain pile shape

    KAUST Repository

    Hsu, Shu-Wei; Keyser, John

    2012-01-01

    structure. Next, for stabilizing the structure, we pick suitable objects from those passing the equilibrium analysis and then restrict their DOFs by managing the insertion of constraints on them. The method is suitable for controlling stacking behavior

  18. Cosmological constraints on Brans-Dicke theory.

    Science.gov (United States)

    Avilez, A; Skordis, C

    2014-07-04

    We report strong cosmological constraints on the Brans-Dicke (BD) theory of gravity using cosmic microwave background data from Planck. We consider two types of models. First, the initial condition of the scalar field is fixed to give the same effective gravitational strength Geff today as the one measured on Earth, GN. In this case, the BD parameter ω is constrained to ω>692 at the 99% confidence level, an order of magnitude improvement over previous constraints. In the second type, the initial condition for the scalar is a free parameter leading to a somewhat stronger constraint of ω>890, while Geff is constrained to 0.981theory and are valid for any Horndeski theory, the most general second-order scalar-tensor theory, which approximates the BD theory on cosmological scales. In this sense, our constraints place strong limits on possible modifications of gravity that might explain cosmic acceleration.

  19. CONSTRAINTS TO USE OF MOBILE TELEPHONY FOR ...

    African Journals Online (AJOL)

    Key words: Constraints, mobile telephony, frequency, farmers and telecommunications service ... efficient sharing of agricultural information ... calls on the mobile phone without the need .... adequate training on the use of mobile .... Job Market.

  20. Modernizing China's Military: Opportunities and Constraints

    National Research Council Canada - National Science Library

    Crane, Keith; Cliff, Roger; Medeiros, Evan; Mulvenon, James; Overholt, William

    2005-01-01

    The purpose of this study is to assess future resource constraints on, and potential domestic economic and industrial contributions to, the ability of the Chinese military to become a significant threat to U.S. forces by 2025...

  1. Optimal capital stock and financing constraints

    OpenAIRE

    Saltari, Enrico; Giuseppe, Travaglini

    2011-01-01

    In this paper we show that financing constraints affect the optimal level of capital stock even when the financing constraint is ineffective. This happens when the firm rationally anticipates that access to external financing resources may be rationed in the future. We will show that with these expectations, the optimal investment policy is to invest less in any given period, thereby lowering the desired optimal capital stock in the long run.

  2. Credit Constraints, Political Instability, and Capital Accumulation

    OpenAIRE

    Risto Herrala; Rima Turk-Ariss

    2013-01-01

    We investigate the complex interactions between credit constraints, political instability, and capital accumulation using a novel approach based on Kiyotaki and Moore’s (1997) theoretical framework. Drawing on a unique firm-level data set from Middle-East and North Africa (MENA), empirical findings point to a large and significant effect of credit conditions on capital accumulation and suggest that continued political unrest worsens credit constraints. The results support the view that financ...

  3. Cyclic labellings with constraints at two distances

    OpenAIRE

    Leese, R; Noble, S D

    2004-01-01

    Motivated by problems in radio channel assignment, we consider the vertex-labelling of graphs with non-negative integers. The objective is to minimise the span of the labelling, subject to constraints imposed at graph distances one and two. We show that the minimum span is (up to rounding) a piecewise linear function of the constraints, and give a complete specification, together with associated optimal assignments, for trees and cycles.

  4. Portfolios with nonlinear constraints and spin glasses

    Science.gov (United States)

    Gábor, Adrienn; Kondor, I.

    1999-12-01

    In a recent paper Galluccio, Bouchaud and Potters demonstrated that a certain portfolio problem with a nonlinear constraint maps exactly onto finding the ground states of a long-range spin glass, with the concomitant nonuniqueness and instability of the optimal portfolios. Here we put forward geometric arguments that lead to qualitatively similar conclusions, without recourse to the methods of spin glass theory, and give two more examples of portfolio problems with convex nonlinear constraints.

  5. Generalized Pauli constraints in small atoms

    Science.gov (United States)

    Schilling, Christian; Altunbulak, Murat; Knecht, Stefan; Lopes, Alexandre; Whitfield, James D.; Christandl, Matthias; Gross, David; Reiher, Markus

    2018-05-01

    The natural occupation numbers of fermionic systems are subject to nontrivial constraints, which include and extend the original Pauli principle. A recent mathematical breakthrough has clarified their mathematical structure and has opened up the possibility of a systematic analysis. Early investigations have found evidence that these constraints are exactly saturated in several physically relevant systems, e.g., in a certain electronic state of the beryllium atom. It has been suggested that, in such cases, the constraints, rather than the details of the Hamiltonian, dictate the system's qualitative behavior. Here, we revisit this question with state-of-the-art numerical methods for small atoms. We find that the constraints are, in fact, not exactly saturated, but that they lie much closer to the surface defined by the constraints than the geometry of the problem would suggest. While the results seem incompatible with the statement that the generalized Pauli constraints drive the behavior of these systems, they suggest that the qualitatively correct wave-function expansions can in some systems already be obtained on the basis of a limited number of Slater determinants, which is in line with numerical evidence from quantum chemistry.

  6. Theater Program Development in Colleges and Universities

    Directory of Open Access Journals (Sweden)

    Gilberto Martinez, Ed.D.

    2013-06-01

    Full Text Available This study sought to find answers to how best colleges and universities can adapt the teaching of theatre in its curriculum. It was then necessary to track the different ways drama has evolved throughout time and how its adoption in formal education has affected its students, both present and past. To this end the researcher examined theater from its earliest inception to its adoption by schools of higher education, more specifically, public colleges and universities.

  7. Our Universe

    Science.gov (United States)

    Stern, Alan

    2001-03-01

    The Universe in which we live is unimaginably vast and ancient, with countless star systems, galaxies, and extraordinary phenomena such as black holes, dark matter, and gamma ray bursts. What phenomena remain mysteries, even to seasoned scientists? Our Universe is a fascinating collection of essays by some of the world's foremost astrophysicists. Some are theorists, some computational modelers, some observers, but all offer their insights into the most cutting-edge, difficult, and curious aspects of astrophysics. Compiled, the essays describe more than the latest techniques and findings. Each of the ten contributors offers a more personal perspective on their work, revealing what motivates them and how their careers and lives have been shaped by their desire to understand our universe. S. Alan Stern is Director of the Department of Space Studies at Southwest Research Institute in Boulder, Colorado. He is a planetary scientist and astrophysicist with both observational and theoretical interests. Stern is an avid pilot and a principal investigator in NASA's planetary research program, and he was selected to be a NASA space shuttle mission specialist finalist. He is the author of more than 100 papers and popular articles. His most recent book is Pluto & Charon (Wiley, 1997). Contributors: Dr. John Huchra, Harvard University Dr. Esther Hu, University of Hawaii, Honolulu Dr. John Mather, NASA Goddard Space Flight Center Dr. Nick Gnedin, University of Colorado, Boulder Dr. Doug Richstone, University of Michigan, Ann Arbor Dr. Bohdan Paczynski, Princeton University, NJ Dr. Megan Donahue, Space Telescope Science Institute, Baltimore, MD Dr. Jerry Ostriker, Princeton University, New Jersey G. Bothun, University of Oregon, Eugene

  8. Future DUNE constraints on EFT

    Science.gov (United States)

    Falkowski, Adam; Grilli di Cortona, Giovanni; Tabrizi, Zahra

    2018-04-01

    In the near future, fundamental interactions at high-energy scales may be most efficiently studied via precision measurements at low energies. A universal language to assemble and interpret precision measurements is the so-called SMEFT, which is an effective field theory (EFT) where the Standard Model (SM) Lagrangian is extended by higher-dimensional operators. In this paper we investigate the possible impact of the DUNE neutrino experiment on constraining the SMEFT. The unprecedented neutrino flux offers an opportunity to greatly improve the current limits via precision measurements of the trident production and neutrino scattering off electrons and nuclei in the DUNE near detector. We quantify the DUNE sensitivity to dimension-6 operators in the SMEFT Lagrangian, and find that in some cases operators suppressed by an O(30) TeV scale can be probed. We also compare the DUNE reach to that of future experiments involving atomic parity violation and polarization asymmetry in electron scattering, which are sensitive to an overlapping set of SMEFT parameters.

  9. Behaviour of and mass transfer at gas-evolving electrodes

    NARCIS (Netherlands)

    Janssen, L.J.J.

    1989-01-01

    A completes set of models for the mass transfer of indicator ions to gas-evolving electrodes with different behaviour of bubbles is described theoretically. Sliding bubbles, rising detached single bubbles, jumping detached coalescence bubbles and ensembles of these types of bubbles are taken into

  10. Analysis of Lamarckian Evolution in Morphologically Evolving Robots

    NARCIS (Netherlands)

    Jelisavcic, Milan; Kiesel, Rafael; Glette, Kyrre; Haasdijk, Evert; Eiben, A.E.

    Evolving robot morphologies implies the need for lifetime learning so that newborn robots can learn to manipulate their bodies. An individual’s morphology will obviously combine traits of all its parents; it must adapt its own controller to suit its morphology, and cannot rely on the controller of

  11. Evolving fuzzy rules for relaxed-criteria negotiation.

    Science.gov (United States)

    Sim, Kwang Mong

    2008-12-01

    In the literature on automated negotiation, very few negotiation agents are designed with the flexibility to slightly relax their negotiation criteria to reach a consensus more rapidly and with more certainty. Furthermore, these relaxed-criteria negotiation agents were not equipped with the ability to enhance their performance by learning and evolving their relaxed-criteria negotiation rules. The impetus of this work is designing market-driven negotiation agents (MDAs) that not only have the flexibility of relaxing bargaining criteria using fuzzy rules, but can also evolve their structures by learning new relaxed-criteria fuzzy rules to improve their negotiation outcomes as they participate in negotiations in more e-markets. To this end, an evolutionary algorithm for adapting and evolving relaxed-criteria fuzzy rules was developed. Implementing the idea in a testbed, two kinds of experiments for evaluating and comparing EvEMDAs (MDAs with relaxed-criteria rules that are evolved using the evolutionary algorithm) and EMDAs (MDAs with relaxed-criteria rules that are manually constructed) were carried out through stochastic simulations. Empirical results show that: 1) EvEMDAs generally outperformed EMDAs in different types of e-markets and 2) the negotiation outcomes of EvEMDAs generally improved as they negotiated in more e-markets.

  12. Friends Drinking Together: Young Adults' Evolving Support Practices

    Science.gov (United States)

    Dresler, Emma; Anderson, Margaret

    2018-01-01

    Purpose: Young adult's drinking is about pleasure, a communal practice of socialising together in a friendship group. The purpose of this paper is to investigate the evolving support practices of drinking groups for better targeting of health communications messages. Design/methodology/approach: This qualitative descriptive study examined the…

  13. Evolving Concepts of Development through the Experience of ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    This project will explore the experiences of emerging and developing countries in order to identify how the concept of international development has evolved and where it they may be heading. It will do so through a series of workshops convening scholars and practitioners from both the developing and the industrialized ...

  14. Heritage – A Conceptually Evolving and Dissonant Phenomenon ...

    African Journals Online (AJOL)

    I therefore, drawing from literature and experiences gained during field observations and focus group interviews, came up with the idea of working with three viewpoints of heritage. Drawing on real life cases I argue that current heritage management and education practices' failure to recognise and respect the evolving, ...

  15. A Conceptual Framework for Evolving, Recommender Online Learning Systems

    Science.gov (United States)

    Peiris, K. Dharini Amitha; Gallupe, R. Brent

    2012-01-01

    A comprehensive conceptual framework is developed and described for evolving recommender-driven online learning systems (ROLS). This framework describes how such systems can support students, course authors, course instructors, systems administrators, and policy makers in developing and using these ROLS. The design science information systems…

  16. Evolving intelligent vehicle control using multi-objective NEAT

    NARCIS (Netherlands)

    Willigen, W.H. van; Haasdijk, E.; Kester, L.J.H.M.

    2013-01-01

    The research in this paper is inspired by a vision of intelligent vehicles that autonomously move along motorways: they join and leave trains of vehicles (platoons), overtake other vehicles, etc. We propose a multi-objective algorithm based on NEAT and SPEA2 that evolves controllers for such

  17. Hormonal evaluation of the infertile male: has it evolved?

    Science.gov (United States)

    Sussman, Ernest M; Chudnovsky, Aleksander; Niederberger, Craig S

    2008-05-01

    An endocrinologic evaluation of patients who have male-factor infertility has clearly evolved and leads to specific diagnoses and treatment strategies in a large population of infertile men. A well-considered endocrine evaluation is especially essential with the ever-growing popularity of assisted reproductive techniques and continued refinements with intracytoplasmic sperm injection.

  18. Regional and Inter-Regional Effects in Evolving Climate Networks

    Czech Academy of Sciences Publication Activity Database

    Hlinka, Jaroslav; Hartman, David; Jajcay, Nikola; Vejmelka, Martin; Donner, R.; Marwan, N.; Kurths, J.; Paluš, Milan

    2014-01-01

    Roč. 21, č. 2 (2014), s. 451-462 ISSN 1023-5809 R&D Projects: GA ČR GCP103/11/J068 Institutional support: RVO:67985807 Keywords : climate networks * evolving networks * principal component analysis * network connectivity * El Nino Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 0.987, year: 2014

  19. Multivariate Epi-splines and Evolving Function Identification Problems

    Science.gov (United States)

    2015-04-15

    such extrinsic information as well as observed function and subgradient values often evolve in applications, we establish conditions under which the...previous study [30] dealt with compact intervals of IR. Splines are intimately tied to optimization problems through their variational theory pioneered...approxima- tion. Motivated by applications in curve fitting, regression, probability density estimation, variogram computation, financial curve construction

  20. Adapting Morphology to Multiple Tasks in Evolved Virtual Creatures

    DEFF Research Database (Denmark)

    Lessin, Dan; Fussell, Don; Miikkulainen, Risto

    2014-01-01

    The ESP method for evolving virtual creatures (Lessin et al., 2013) consisted of an encapsulation mechanism to preserve learned skills, a human-designed syllabus to build higherlevel skills by combining lower-level skills systematically, and a pandemonium mechanism to resolve conflicts between...

  1. Exploring the Evolving Professional Identity of Novice School Counselors

    Science.gov (United States)

    Bamgbose, Olamojiba Omolara

    2017-01-01

    The study employed a grounded theory approach to explore the evolving professional identity of novice school counselors. Participants, who are currently employed as school counselors at the elementary, middle, or high school level with 1-4 years' experience, were career changers from other helping professions and graduates from an intensive school…

  2. Evaluation and testing methodology for evolving entertainment systems

    NARCIS (Netherlands)

    Jurgelionis, A.; Bellotti, F.; IJsselsteijn, W.A.; Kort, de Y.A.W.; Bernhaupt, R.; Tscheligi, M.

    2007-01-01

    This paper presents a testing and evaluation methodology for evolving pervasive gaming and multimedia systems. We introduce the Games@Large system, a complex gaming and multimedia architecture comprised of a multitude of elements: heterogeneous end user devices, wireless and wired network

  3. Degree distribution of a new model for evolving networks

    Indian Academy of Sciences (India)

    on intuitive but realistic consideration that nodes are added to the network with both preferential and random attachments. The degree distribution of the model is between a power-law and an exponential decay. Motivated by the features of network evolution, we introduce a new model of evolving networks, incorporating the ...

  4. Evolving Nature of Sexual Orientation and Gender Identity

    Science.gov (United States)

    Jourian, T. J.

    2015-01-01

    This chapter discusses the historical and evolving terminology, constructs, and ideologies that inform the language used by those who are lesbian, gay, bisexual, and same-gender loving, who may identify as queer, as well as those who are members of trans* communities from multiple and intersectional perspectives.

  5. The Evolving Military Learner Population: A Review of the Literature

    Science.gov (United States)

    Ford, Kate; Vignare, Karen

    2015-01-01

    This literature review examines the evolving online military learner population with emphasis on current generation military learners, who are most frequently Post-9/11 veterans. The review synthesizes recent scholarly and grey literature on military learner demographics and attributes, college experiences, and academic outcomes against a backdrop…

  6. The evolving role of governments in the nuclear energy field

    International Nuclear Information System (INIS)

    Anon.

    2004-01-01

    The NEA Nuclear Development Committee (NDC) recently completed a study that looks into the evolving role of governments in nuclear energy matters. Many decisions on government intervention in recent decades have been based on the earlier experience of what works best. The report suggests some considerations that all governments could take into account when establishing their respective roles. (author)

  7. Evolving information systems: meeting the ever-changing environment

    NARCIS (Netherlands)

    Oei, J.L.H.; Proper, H.A.; Falkenberg, E.D.

    1994-01-01

    To meet the demands of organizations and their ever-changing environment, information systems are required which are able to evolve to the same extent as organizations do. Such a system has to support changes in all time-and application-dependent aspects. In this paper, requirements and a conceptual

  8. You 3.0: The Most Important Evolving Technology

    Science.gov (United States)

    Tamarkin, Molly; Bantz, David A.; Childs, Melody; diFilipo, Stephen; Landry, Stephen G.; LoPresti, Frances; McDonald, Robert H.; McGuthry, John W.; Meier, Tina; Rodrigo, Rochelle; Sparrow, Jennifer; Diggs, D. Teddy; Yang, Catherine W.

    2010-01-01

    That technology evolves is a given. Not as well understood is the impact of technological evolution on each individual--on oneself, one's skill development, one's career, and one's relationship with the work community. The authors believe that everyone in higher education will become an IT worker and that IT workers will be managing a growing…

  9. Sextant: Visualizing time-evolving linked geospatial data

    NARCIS (Netherlands)

    C. Nikolaou (Charalampos); K. Dogani (Kallirroi); K. Bereta (Konstantina); G. Garbis (George); M. Karpathiotakis (Manos); K. Kyzirakos (Konstantinos); M. Koubarakis (Manolis)

    2015-01-01

    textabstractThe linked open data cloud is constantly evolving as datasets get continuously updated with newer versions. As a result, representing, querying, and visualizing the temporal dimension of linked data is crucial. This is especially important for geospatial datasets that form the backbone

  10. Reduction Of Constraints For Coupled Operations

    International Nuclear Information System (INIS)

    Raszewski, F.; Edwards, T.

    2009-01-01

    The homogeneity constraint was implemented in the Defense Waste Processing Facility (DWPF) Product Composition Control System (PCCS) to help ensure that the current durability models would be applicable to the glass compositions being processed during DWPF operations. While the homogeneity constraint is typically an issue at lower waste loadings (WLs), it may impact the operating windows for DWPF operations, where the glass forming systems may be limited to lower waste loadings based on fissile or heat load limits. In the sludge batch 1b (SB1b) variability study, application of the homogeneity constraint at the measurement acceptability region (MAR) limit eliminated much of the potential operating window for DWPF. As a result, Edwards and Brown developed criteria that allowed DWPF to relax the homogeneity constraint from the MAR to the property acceptance region (PAR) criterion, which opened up the operating window for DWPF operations. These criteria are defined as: (1) use the alumina constraint as currently implemented in PCCS (Al 2 O 3 (ge) 3 wt%) and add a sum of alkali constraint with an upper limit of 19.3 wt% (ΣM 2 O 2 O 3 constraint to 4 wt% (Al 2 O 3 (ge) 4 wt%). Herman et al. previously demonstrated that these criteria could be used to replace the homogeneity constraint for future sludge-only batches. The compositional region encompassing coupled operations flowsheets could not be bounded as these flowsheets were unknown at the time. With the initiation of coupled operations at DWPF in 2008, the need to revisit the homogeneity constraint was realized. This constraint was specifically addressed through the variability study for SB5 where it was shown that the homogeneity constraint could be ignored if the alumina and alkali constraints were imposed. Additional benefit could be gained if the homogeneity constraint could be replaced by the Al 2 O 3 and sum of alkali constraint for future coupled operations processing based on projections from Revision 14 of

  11. Xe isotopic constraints on cycling of deep Earth volatiles

    Science.gov (United States)

    Parai, R.; Mukhopadhyay, S.

    2017-12-01

    The modern deep Earth volatile budget reflects primordial volatiles delivered during accretion, radiogenic ingrowth of volatile species (e.g., 40Ar produced by 40K decay), outgassing in association with mantle processing, and regassing via subduction. The noble gases are unique volatile tracers in that they are chemically inert, but are thought to be trapped within hydrous alteration phases in downwelling lithologies. Noble gases thus provide a tracer of volatile transport between the deep Earth and surface reservoirs. Constraints on the fluxes of noble gases between deep Earth and surface reservoirs over time can accordingly be used to provide insight into temperature conditions at subduction zones, limits on volatile cycling, and the evolving distribution of major volatile species in terrestrial reservoirs over time. Xe isotope systematics in mantle-derived rocks show that 80-90% of the mantle Xe budget is derived from recycling of atmospheric Xe, indicating that atmospheric Xe is retained in subducting slabs beyond depths of magma generation in subduction zones over Earth history. We present an integrated model of Xe cycling between the mantle and atmosphere in association with mantle processing over Earth history. We test a wide variety of outgassing and regassing rates and take the evolution of the atmospheric Xe isotopic composition [e.g., 1] into account. Models in which the deep Earth transitions from a net outgassing to net regassing regime best satisfy Xe isotopic constraints from mantle-derived rocks [2-6]. [1] Avice et al., 2017; Nature Communications, 8; [2] Mukhopadhyay, 2012, Nature 486, 101-104; [3] Parai et al., 2012, EPSL 359-360, 227-239; [4] Parai and Mukhopadhay, 2015, G-cubed 16, 719-735; [5] Peto et al., 2013, EPSL 369-370, 13-23; [6] Tucker et al., 2012, EPSL 355-356, 244-254.

  12. University autonomy as sensemaking

    DEFF Research Database (Denmark)

    Lind, Jonas Krog

    The formal autonomy of universities in Europe has generally increased over recent decades. However, new forms of accountability measures and more indirect state steering have accompanied this development, making it difficult to assess the actual autonomy. The article addresses this problem...... by applying the sensemaking approach to the study of organizational autonomy. Enacted autonomy is suggested as a new conceptualization that challenges the basic assumption in studies on formal autonomy that autonomy is only about external constraints on action. It does so by insisting on the active subjects...... in the enactment of the environment, thereby questioning the validity of a clear distinction between what is internal and what is external to an organization. By acknowledging the subjective dimension of autonomy, a set of stylized identities is developed as a tool for understanding the enactment of autonomy...

  13. Constraint-Muse: A Soft-Constraint Based System for Music Therapy

    Science.gov (United States)

    Hölzl, Matthias; Denker, Grit; Meier, Max; Wirsing, Martin

    Monoidal soft constraints are a versatile formalism for specifying and solving multi-criteria optimization problems with dynamically changing user preferences. We have developed a prototype tool for interactive music creation, called Constraint Muse, that uses monoidal soft constraints to ensure that a dynamically generated melody harmonizes with input from other sources. Constraint Muse provides an easy to use interface based on Nintendo Wii controllers and is intended to be used in music therapy for people with Parkinson’s disease and for children with high-functioning autism or Asperger’s syndrome.

  14. Adaptive inferential sensors based on evolving fuzzy models.

    Science.gov (United States)

    Angelov, Plamen; Kordon, Arthur

    2010-04-01

    A new technique to the design and use of inferential sensors in the process industry is proposed in this paper, which is based on the recently introduced concept of evolving fuzzy models (EFMs). They address the challenge that the modern process industry faces today, namely, to develop such adaptive and self-calibrating online inferential sensors that reduce the maintenance costs while keeping the high precision and interpretability/transparency. The proposed new methodology makes possible inferential sensors to recalibrate automatically, which reduces significantly the life-cycle efforts for their maintenance. This is achieved by the adaptive and flexible open-structure EFM used. The novelty of this paper lies in the following: (1) the overall concept of inferential sensors with evolving and self-developing structure from the data streams; (2) the new methodology for online automatic selection of input variables that are most relevant for the prediction; (3) the technique to detect automatically a shift in the data pattern using the age of the clusters (and fuzzy rules); (4) the online standardization technique used by the learning procedure of the evolving model; and (5) the application of this innovative approach to several real-life industrial processes from the chemical industry (evolving inferential sensors, namely, eSensors, were used for predicting the chemical properties of different products in The Dow Chemical Company, Freeport, TX). It should be noted, however, that the methodology and conclusions of this paper are valid for the broader area of chemical and process industries in general. The results demonstrate that well-interpretable and with-simple-structure inferential sensors can automatically be designed from the data stream in real time, which predict various process variables of interest. The proposed approach can be used as a basis for the development of a new generation of adaptive and evolving inferential sensors that can address the

  15. Evolvable mathematical models: A new artificial Intelligence paradigm

    Science.gov (United States)

    Grouchy, Paul

    We develop a novel Artificial Intelligence paradigm to generate autonomously artificial agents as mathematical models of behaviour. Agent/environment inputs are mapped to agent outputs via equation trees which are evolved in a manner similar to Symbolic Regression in Genetic Programming. Equations are comprised of only the four basic mathematical operators, addition, subtraction, multiplication and division, as well as input and output variables and constants. From these operations, equations can be constructed that approximate any analytic function. These Evolvable Mathematical Models (EMMs) are tested and compared to their Artificial Neural Network (ANN) counterparts on two benchmarking tasks: the double-pole balancing without velocity information benchmark and the challenging discrete Double-T Maze experiments with homing. The results from these experiments show that EMMs are capable of solving tasks typically solved by ANNs, and that they have the ability to produce agents that demonstrate learning behaviours. To further explore the capabilities of EMMs, as well as to investigate the evolutionary origins of communication, we develop NoiseWorld, an Artificial Life simulation in which interagent communication emerges and evolves from initially noncommunicating EMM-based agents. Agents develop the capability to transmit their x and y position information over a one-dimensional channel via a complex, dialogue-based communication scheme. These evolved communication schemes are analyzed and their evolutionary trajectories examined, yielding significant insight into the emergence and subsequent evolution of cooperative communication. Evolved agents from NoiseWorld are successfully transferred onto physical robots, demonstrating the transferability of EMM-based AIs from simulation into physical reality.

  16. The Purine Bias of Coding Sequences is Determined by Physicochemical Constraints on Proteins.

    Science.gov (United States)

    Ponce de Leon, Miguel; de Miranda, Antonio Basilio; Alvarez-Valin, Fernando; Carels, Nicolas

    2014-01-01

    For this report, we analyzed protein secondary structures in relation to the statistics of three nucleotide codon positions. The purpose of this investigation was to find which properties of the ribosome, tRNA or protein level, could explain the purine bias (Rrr) as it is observed in coding DNA. We found that the Rrr pattern is the consequence of a regularity (the codon structure) resulting from physicochemical constraints on proteins and thermodynamic constraints on ribosomal machinery. The physicochemical constraints on proteins mainly come from the hydropathy and molecular weight (MW) of secondary structures as well as the energy cost of amino acid synthesis. These constraints appear through a network of statistical correlations, such as (i) the cost of amino acid synthesis, which is in favor of a higher level of guanine in the first codon position, (ii) the constructive contribution of hydropathy alternation in proteins, (iii) the spatial organization of secondary structure in proteins according to solvent accessibility, (iv) the spatial organization of secondary structure according to amino acid hydropathy, (v) the statistical correlation of MW with protein secondary structures and their overall hydropathy, (vi) the statistical correlation of thymine in the second codon position with hydropathy and the energy cost of amino acid synthesis, and (vii) the statistical correlation of adenine in the second codon position with amino acid complexity and the MW of secondary protein structures. Amino acid physicochemical properties and functional constraints on proteins constitute a code that is translated into a purine bias within the coding DNA via tRNAs. In that sense, the Rrr pattern within coding DNA is the effect of information transfer on nucleotide composition from protein to DNA by selection according to the codon positions. Thus, coding DNA structure and ribosomal machinery co-evolved to minimize the energy cost of protein coding given the functional

  17. The United Nations University and Information Development.

    Science.gov (United States)

    Tanaskovic, Ines Wesley

    1994-01-01

    Describes the role of the United Nations University (UNU) in promoting the effective use of new information technologies in support of science and technology for development. The UNU Information and Decision Systems (INDES) project examines the constraints preventing developing nations from using advances in informatics and from integrating their…

  18. Funding the Technology of a Research University

    Science.gov (United States)

    Ostrom-Blonigen, Jean

    2013-01-01

    Using the central information technology unit (CITU) on the North Dakota State University (NDSU) campus, this project triangulated two independent studies in an effort to converge data findings. The studies were conducted in an effort to determine whether CITU's budget constraints were known to its stakeholders and how the extended use of the…

  19. Cosmological constraints from supernova data set with corrected redshift

    International Nuclear Information System (INIS)

    Feoli, A; Rillo, V; Grasso, M; Mancini, L

    2012-01-01

    Observations of distant type Ia supernovae (SNe Ia), used as standard candles, support the notion that the Cosmos is filled with a mysterious form of energy, the dark energy. The constraints on cosmological parameters derived from data of SNe Ia and the measurements of the cosmic microwave background anisotropies indicate that the dark energy amounts to≅ 70% of all the energy contained in the Universe. In the hypothesis of a flat Universe (Ω m + Ω Λ = 1), we investigate if the dark energy is really required in order to explain the SNe Ia experimental data, and, in this case, how much of such unknown energy is actually deduced from the analysis of these data and must be introduced in the ΛCDM model of cosmology. In particular we are interested in verifying if the Einstein-de Sitter model of the expanding Universe is really to be ruled out. By using a fitting procedure based on the Newton method search for a minimum, we reanalyzed the 'Union compilation' reported by Kowalski et al. (2008) formed by 307 SNe, obtaining a very different estimate of the dark energy, that is≅ 60%. Furthermore, in order to balance the correction of the apparent magnitude of SNe Ia, due to the dilation or stretching of the corresponding light curve width, we introduce a suitable modified redsfhit. Taking into account this correction, we refitted the Union compilation dataset after a selection cut. The main result that emerges from our analysis is that the values of Ω m and Ω Λ strongly depend on the fitting procedure and the selected sample. In particular, the constraint we obtain on the mass density, normalized by the critical mass density, is Ω m = 0.7 for a sample of 252, and Ω m = 1 for a sample of 242 SNe Ia respectively. The latter case does not imply the existence of any additional form of dark energy.

  20. Intelligent Universe

    Energy Technology Data Exchange (ETDEWEB)

    Hoyle, F

    1983-01-01

    The subject is covered in chapters, entitled: chance and the universe (synthesis of proteins; the primordial soup); the gospel according to Darwin (discussion of Darwin theory of evolution); life did not originate on earth (fossils from space; life in space); the interstellar connection (living dust between the stars; bacteria in space falling to the earth; interplanetary dust); evolution by cosmic control (microorganisms; genetics); why aren't the others here (a cosmic origin of life); after the big bang (big bang and steady state); the information rich universe; what is intelligence up to; the intelligent universe.

  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. Runaway universe

    Energy Technology Data Exchange (ETDEWEB)

    Davies, P

    1978-01-01

    The subject is covered in chapters entitled: the emerging universe (general introduction, history of astronomical and cosmological research, origins, the expanding universe, stars, galaxies, electromagnetic radiation); primeval fire (the big bang model, origin of the elements, properties of the elements and of sub-atomic particles); order out of chaos (galactic evolution, star formation, nuclear fusion, the solar system, origin of life on Earth); a star called Sol (properties of the sun and of other stars); life in the universe; the catastrophe principle (the rise and fall of cosmic order); stardoom (star evolution, neutron stars); black holes and superholes (gravitational collapse); technology and survival; the dying universe (second law of thermodynamics); worlds without end (cosmological models).

  3. Rhodes University

    African Journals Online (AJOL)

    Samridhi Sharma

    2013-10-29

    Oct 29, 2013 ... been taken may improve the reception, by the target audience, of the intended communication. This may ... alcohol marketing. Similarly .... of the intended users (Rhodes University support staff ..... Digital Human Modeling and.

  4. 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.

  5. A Generalized Radiation Model for Human Mobility: Spatial Scale, Searching Direction and Trip Constraint.

    Directory of Open Access Journals (Sweden)

    Chaogui Kang

    Full Text Available We generalized the recently introduced "radiation model", as an analog to the generalization of the classic "gravity model", to consolidate its nature of universality for modeling diverse mobility systems. By imposing the appropriate scaling exponent λ, normalization factor κ and system constraints including searching direction and trip OD constraint, the generalized radiation model accurately captures real human movements in various scenarios and spatial scales, including two different countries and four different cities. Our analytical results also indicated that the generalized radiation model outperformed alternative mobility models in various empirical analyses.

  6. Fuzzy Constraint-Based Agent Negotiation

    Institute of Scientific and Technical Information of China (English)

    Menq-Wen Lin; K. Robert Lai; Ting-Jung Yu

    2005-01-01

    Conflicts between two or more parties arise for various reasons and perspectives. Thus, resolution of conflicts frequently relies on some form of negotiation. This paper presents a general problem-solving framework for modeling multi-issue multilateral negotiation using fuzzy constraints. Agent negotiation is formulated as a distributed fuzzy constraint satisfaction problem (DFCSP). Fuzzy constrains are thus used to naturally represent each agent's desires involving imprecision and human conceptualization, particularly when lexical imprecision and subjective matters are concerned. On the other hand, based on fuzzy constraint-based problem-solving, our approach enables an agent not only to systematically relax fuzzy constraints to generate a proposal, but also to employ fuzzy similarity to select the alternative that is subject to its acceptability by the opponents. This task of problem-solving is to reach an agreement that benefits all agents with a high satisfaction degree of fuzzy constraints, and move towards the deal more quickly since their search focuses only on the feasible solution space. An application to multilateral negotiation of a travel planning is provided to demonstrate the usefulness and effectiveness of our framework.

  7. Pair Production Constraints on Superluminal Neutrinos Revisited

    International Nuclear Information System (INIS)

    Brodsky, Stanley

    2012-01-01

    We revisit the pair creation constraint on superluminal neutrinos considered by Cohen and Glashow in order to clarify which types of superluminal models are constrained. We show that a model in which the superluminal neutrino is effectively light-like can evade the Cohen-Glashow constraint. In summary, any model for which the CG pair production process operates is excluded because such timelike neutrinos would not be detected by OPERA or other experiments. However, a superluminal neutrino which is effectively lightlike with fixed p 2 can evade the Cohen-Glashow constraint because of energy-momentum conservation. The coincidence involved in explaining the SN1987A constraint certainly makes such a picture improbable - but it is still intrinsically possible. The lightlike model is appealing in that it does not violate Lorentz symmetry in particle interactions, although one would expect Hughes-Drever tests to turn up a violation eventually. Other evasions of the CG constraints are also possible; perhaps, e.g., the neutrino takes a 'short cut' through extra dimensions or suffers anomalous acceleration in matter. Irrespective of the OPERA result, Lorentz-violating interactions remain possible, and ongoing experimental investigation of such possibilities should continue.

  8. Faddeev-Jackiw quantization and constraints

    International Nuclear Information System (INIS)

    Barcelos-Neto, J.; Wotzasek, C.

    1992-01-01

    In a recent Letter, Faddeev and Jackiw have shown that the reduction of constrained systems into its canonical, first-order form, can bring some new insight into the research of this field. For sympletic manifolds the geometrical structure, called Dirac or generalized bracket, is obtained directly from the inverse of the nonsingular sympletic two-form matrix. In the cases of nonsympletic manifolds, this two-form is degenerated and cannot be inverted to provide the generalized brackets. This singular behavior of the sympletic matrix is indicative of the presence of constraints that have to be carefully considered to yield to consistent results. One has two possible routes to treat this problem: Dirac has taught us how to implement the constraints into the potential part (Hamiltonian) of the canonical Lagrangian, leading to the well-known Dirac brackets, which are consistent with the constraints and can be mapped into quantum commutators (modulo ordering terms). The second route, suggested by Faddeev and Jackiw, and followed in this paper, is to implement the constraints directly into the canonical part of the first order Lagrangian, using the fact that the consistence condition for the stability of the constrained manifold is linear in the time derivative. This algorithm may lead to an invertible two-form sympletic matrix from where the Dirac brackets are readily obtained. This algorithm is used in this paper to investigate some aspects of the quantization of constrained systems with first- and second-class constraints in the sympletic approach

  9. Black Hole Universe Model and Dark Energy

    Science.gov (United States)

    Zhang, Tianxi

    2011-01-01

    Considering black hole as spacetime and slightly modifying the big bang theory, the author has recently developed a new cosmological model called black hole universe, which is consistent with Mach principle and Einsteinian general relativity and self consistently explains various observations of the universe without difficulties. According to this model, the universe originated from a hot star-like black hole and gradually grew through a supermassive black hole to the present universe by accreting ambient material and merging with other black holes. The entire space is infinitely and hierarchically layered and evolves iteratively. The innermost three layers are the universe that we lives, the outside space called mother universe, and the inside star-like and supermassive black holes called child universes. The outermost layer has an infinite radius and zero limits for both the mass density and absolute temperature. All layers or universes are governed by the same physics, the Einstein general relativity with the Robertson-Walker metric of spacetime, and tend to expand outward physically. When one universe expands out, a new similar universe grows up from its inside black holes. The origin, structure, evolution, expansion, and cosmic microwave background radiation of black hole universe have been presented in the recent sequence of American Astronomical Society (AAS) meetings and published in peer-review journals. This study will show how this new model explains the acceleration of the universe and why dark energy is not required. We will also compare the black hole universe model with the big bang cosmology.

  10. CHANDRA CLUSTER COSMOLOGY PROJECT III: COSMOLOGICAL PARAMETER CONSTRAINTS

    International Nuclear Information System (INIS)

    Vikhlinin, A.; Forman, W. R.; Jones, C.; Murray, S. S.; Kravtsov, A. V.; Burenin, R. A.; Voevodkin, A.; Ebeling, H.; Hornstrup, A.; Nagai, D.; Quintana, H.

    2009-01-01

    Chandra observations of large samples of galaxy clusters detected in X-rays by ROSAT provide a new, robust determination of the cluster mass functions at low and high redshifts. Statistical and systematic errors are now sufficiently small, and the redshift leverage sufficiently large for the mass function evolution to be used as a useful growth of a structure-based dark energy probe. In this paper, we present cosmological parameter constraints obtained from Chandra observations of 37 clusters with (z) = 0.55 derived from 400 deg 2 ROSAT serendipitous survey and 49 brightest z ∼ 0.05 clusters detected in the All-Sky Survey. Evolution of the mass function between these redshifts requires Ω Λ > 0 with a ∼5σ significance, and constrains the dark energy equation-of-state parameter to w 0 = -1.14 ± 0.21, assuming a constant w and a flat universe. Cluster information also significantly improves constraints when combined with other methods. Fitting our cluster data jointly with the latest supernovae, Wilkinson Microwave Anisotropy Probe, and baryonic acoustic oscillation measurements, we obtain w 0 = -0.991 ± 0.045 (stat) ±0.039 (sys), a factor of 1.5 reduction in statistical uncertainties, and nearly a factor of 2 improvement in systematics compared with constraints that can be obtained without clusters. The joint analysis of these four data sets puts a conservative upper limit on the masses of light neutrinos Σm ν M h and σ 8 from the low-redshift cluster mass function.

  11. Clustering impact regime with shocks in freely evolving granular gas

    Science.gov (United States)

    Isobe, Masaharu

    2017-06-01

    A freely cooling granular gas without any external force evolves from the initial homogeneous state to the inhomogeneous clustering state, at which the energy decay deviates from the Haff's law. The asymptotic behavior of energy in the inelastic hard sphere model have been predicted by several theories, which are based on the mode coupling theory or extension of inelastic hard rods gas. In this study, we revisited the clustering regime of freely evolving granular gas via large-scale molecular dynamics simulation with up to 16.7 million inelastic hard disks. We found novel regime regarding on collisions between "clusters" spontaneously appearing after clustering regime, which can only be identified more than a few million particles system. The volumetric dilatation pattern of semicircular shape originated from density shock propagation are well characterized on the appearing of "cluster impact" during the aggregation process of clusters.

  12. Finding evolved stars in the inner Galactic disk with Gaia

    Science.gov (United States)

    Quiroga-Nuñez, L. H.; van Langevelde, H. J.; Pihlström, Y. M.; Sjouwerman, L. O.; Brown, A. G. A.

    2018-04-01

    The Bulge Asymmetries and Dynamical Evolution (BAaDE) survey will provide positions and line-of-sight velocities of ~20, 000 evolved, maser bearing stars in the Galactic plane. Although this Galactic region is affected by optical extinction, BAaDE targets may have Gaia cross-matches, eventually providing additional stellar information. In an initial attempt to cross-match BAaDE targets with Gaia, we have found more than 5,000 candidates. Of these, we may expect half to show SiO emission, which will allow us to obtain velocity information. The cross-match is being refined to avoid false positives using different criteria based on distance analysis, flux variability, and color assessment in the mid- and near-IR. Once the cross-matches can be confirmed, we will have a unique sample to characterize the stellar population of evolved stars in the Galactic bulge, which can be considered fossils of the Milky Way formation.

  13. Self-regulating and self-evolving particle swarm optimizer

    Science.gov (United States)

    Wang, Hui-Min; Qiao, Zhao-Wei; Xia, Chang-Liang; Li, Liang-Yu

    2015-01-01

    In this article, a novel self-regulating and self-evolving particle swarm optimizer (SSPSO) is proposed. Learning from the idea of direction reversal, self-regulating behaviour is a modified position update rule for particles, according to which the algorithm improves the best position to accelerate convergence in situations where the traditional update rule does not work. Borrowing the idea of mutation from evolutionary computation, self-evolving behaviour acts on the current best particle in the swarm to prevent the algorithm from prematurely converging. The performance of SSPSO and four other improved particle swarm optimizers is numerically evaluated by unimodal, multimodal and rotated multimodal benchmark functions. The effectiveness of SSPSO in solving real-world problems is shown by the magnetic optimization of a Halbach-based permanent magnet machine. The results show that SSPSO has good convergence performance and high reliability, and is well matched to actual problems.

  14. AUTOMOTIVE APPLICATIONS OF EVOLVING TAKAGI-SUGENO-KANG FUZZY MODELS

    Directory of Open Access Journals (Sweden)

    Radu-Emil Precup

    2017-08-01

    Full Text Available This paper presents theoretical and application results concerning the development of evolving Takagi-Sugeno-Kang fuzzy models for two dynamic systems, which will be viewed as controlled processes, in the field of automotive applications. The two dynamic systems models are nonlinear dynamics of the longitudinal slip in the Anti-lock Braking Systems (ABS and the vehicle speed in vehicles with the Continuously Variable Transmission (CVT systems. The evolving Takagi-Sugeno-Kang fuzzy models are obtained as discrete-time fuzzy models by incremental online identification algorithms. The fuzzy models are validated against experimental results in the case of the ABS and the first principles simulation results in the case of the vehicle with the CVT.

  15. Design of the tool for periodic not evolvent profiles

    Directory of Open Access Journals (Sweden)

    Anisimov Roman

    2017-01-01

    Full Text Available The new approach to profiling of the tool for processing of parts with periodic not evolvent profiles are considered in the article The discriminatory analysis of periodic profiles including repetition of profile both in the plane of perpendicular axis of part, and in the plane of passing along part of axis is offered. In the basis of the offered profiling method the idea of space shaping by rated surface of product of tool surface lies. The big advantage of the offered approach in profiling is its combination with the analysis of parameters of process of engineering work. It allows to predict the accuracy and surface quality of product with not evolvent periodic profile. While using the offered approach the pinion cutter for processing of wheels with internal triangular teeths and mill for processing of the screw of the counter of consumption of liquid, complex profile of which consists of several formings, have been received

  16. Evolvability of thermophilic proteins from archaea and bacteria.

    Science.gov (United States)

    Takano, Kazufumi; Aoi, Atsushi; Koga, Yuichi; Kanaya, Shigenori

    2013-07-16

    Proteins from thermophiles possess high thermostability. The stabilization mechanisms differ between archaeal and bacterial proteins, whereby archaeal proteins are mainly stabilized via hydrophobic interactions and bacterial proteins by ion pairs. High stability is an important factor in promoting protein evolution, but the precise means by which different stabilization mechanisms affect the evolution process remain unclear. In this study, we investigated a random mutational drift of esterases from thermophilic archaea and bacteria at high temperatures. Our results indicate that mutations in archaeal proteins lead to improved function with no loss of stability, while mutant bacterial proteins are largely destabilized with decreased activity at high temperatures. On the basis of these findings, we suggest that archaeal proteins possess higher "evolvability" than bacterial proteins under temperature selection and are additionally able to evolve into eukaryotic proteins.

  17. Real-time evolvable pulse shaper for radiation measurements

    Energy Technology Data Exchange (ETDEWEB)

    Lanchares, Juan, E-mail: julandan@dacya.ucm.es [Facultad de Informática, Universidad Complutense de Madrid (UCM), C/Prof. José García Santesmases s/n, 28040 Madrid (Spain); Garnica, Oscar, E-mail: ogarnica@dacya.ucm.es [Facultad de Informática, Universidad Complutense de Madrid (UCM), C/Prof. José García Santesmases s/n, 28040 Madrid (Spain); Risco-Martín, José L., E-mail: jlrisco@dacya.ucm.es [Facultad de Informática, Universidad Complutense de Madrid (UCM), C/Prof. José García Santesmases s/n, 28040 Madrid (Spain); Ignacio Hidalgo, J., E-mail: hidalgo@dacya.ucm.es [Facultad de Informática, Universidad Complutense de Madrid (UCM), C/Prof. José García Santesmases s/n, 28040 Madrid (Spain); Regadío, Alberto, E-mail: alberto.regadio@insa.es [Área de Tecnologías Electrónicas, Instituto Nacional de Técnica Aeroespacial (INTA), 28850 Torrejón de Ardoz, Madrid (Spain)

    2013-11-01

    In the last two decades, recursive algorithms for real-time digital pulse shaping in pulse height measurements have been developed and published in number of articles and textbooks. All these algorithms try to synthesize in real time optimum or near optimum shapes in the presence of noise. Even though some of these shapers can be considered effective designs, some side effects like aging cannot be ignored. We may observe that after sensors degradation, the signal obtained is not valid. In this regard, we present in this paper a novel technique that, based on evolvable hardware concepts, is able to evolve the degenerated shaper into a new design with better performance than the original one under the new sensor features.

  18. Programming adaptive control to evolve increased metabolite production.

    Science.gov (United States)

    Chou, Howard H; Keasling, Jay D

    2013-01-01

    The complexity inherent in biological systems challenges efforts to rationally engineer novel phenotypes, especially those not amenable to high-throughput screens and selections. In nature, increased mutation rates generate diversity in a population that can lead to the evolution of new phenotypes. Here we construct an adaptive control system that increases the mutation rate in order to generate diversity in the population, and decreases the mutation rate as the concentration of a target metabolite increases. This system is called feedback-regulated evolution of phenotype (FREP), and is implemented with a sensor to gauge the concentration of a metabolite and an actuator to alter the mutation rate. To evolve certain novel traits that have no known natural sensors, we develop a framework to assemble synthetic transcription factors using metabolic enzymes and construct four different sensors that recognize isopentenyl diphosphate in bacteria and yeast. We verify FREP by evolving increased tyrosine and isoprenoid production.

  19. Evolving approaches to the ethical management of genomic data.

    Science.gov (United States)

    McEwen, Jean E; Boyer, Joy T; Sun, Kathie Y

    2013-06-01

    The ethical landscape in the field of genomics is rapidly shifting. Plummeting sequencing costs, along with ongoing advances in bioinformatics, now make it possible to generate an enormous volume of genomic data about vast numbers of people. The informational richness, complexity, and frequently uncertain meaning of these data, coupled with evolving norms surrounding the sharing of data and samples and persistent privacy concerns, have generated a range of approaches to the ethical management of genomic information. As calls increase for the expanded use of broad or even open consent, and as controversy grows about how best to handle incidental genomic findings, these approaches, informed by normative analysis and empirical data, will continue to evolve alongside the science. Published by Elsevier Ltd.

  20. Carbon chemistry in dense molecular clouds: Theory and observational constraints

    International Nuclear Information System (INIS)

    Blake, G.A.

    1990-01-01

    For the most part, gas phase models of the chemistry of dense molecular clouds predict the abundances of simple species rather well. However, for larger molecules and even for small systems rich in carbon these models often fail spectacularly. Researchers present a brief review of the basic assumptions and results of large scale modeling of the carbon chemistry in dense molecular clouds. Particular attention is to the influence of the gas phase C/O ratio in molecular clouds, and the likely role grains play in maintaining this ratio as clouds evolve from initially diffuse objects to denser cores with associated stellar and planetary formation. Recent spectral line surveys at centimeter and millimeter wavelengths along with selected observations in the submillimeter have now produced an accurate inventory of the gas phase carbon budget in several different types of molecular clouds, though gaps in our knowledge clearly remain. The constraints these observations place on theoretical models of interstellar chemistry can be used to gain insights into why the models fail, and show also which neglected processes must be included in more complete analyses. Looking toward the future, larger molecules are especially difficult to study both experimentally and theoretically in such dense, cold regions, and some new methods are therefore outlined which may ultimately push the detectability of small carbon chains and rings to much heavier species