Temperature and heat flux scaling laws for isoviscous, infinite Prandtl number mixed heating convection

NASA Astrophysics Data System (ADS)

Vilella, Kenny; Deschamps, Frédéric

2018-07-01

Thermal evolution of terrestrial planets is controlled by heat transfer through their silicate mantles. A suitable framework for modelling this heat transport is a system including bottom heating (from the core) and internal heating, for example, generated by secular cooling or by the decay of radioactive isotopes. The mechanism of heat transfer depends on the physical properties of the system. In systems where convection is able to operate, two different regimes are possible depending on the relative amount of bottom and internal heating. For moderate internal heating rates, the system is composed of active hot upwellings and cold downwellings. For large internal heating rates, the bottom heat flux becomes negative and the system is only composed of active cold downwellings. Here, we build theoretical scaling laws for both convective regimes following the approach of Vilella & Kaminski (2017), which links the surface heat flux and the temperature jump across both the top and the bottom thermal boundary layer (TBL) to the Rayleigh number and the dimensionless internal heating rate. Theoretical predictions are then verified against numerical simulations performed in 2-D and 3-D Cartesiangeometry, and covering a large range of the parameter space. Our theoretical scaling laws are more successful in predicting the thermal structure of systems with large internal heating rates than that of systems with no or moderate internal heating. The differences between moderate and large internal heating rates are interpreted as differences in the mechanisms generating thermal instabilities. We identified three mechanisms: conductive growth of the TBL, instability impacting, and TBL erosion, the last two being present only for moderate internal heating rates, in which hot plumes are generated at the bottom of the system and are able to reach the surface. Finally, we apply our scaling laws to the evolution of the early Earth, proposing a new model for the cooling of the primordial magma ocean that reconciles geochemical observations and magma ocean dynamics.

Temperature and heat flux scaling laws for isoviscous, infinite Prandtl number mixed heating convection.

NASA Astrophysics Data System (ADS)

Vilella, Kenny; Deschamps, Frederic

2018-04-01

Thermal evolution of terrestrial planets is controlled by heat transfer through their silicate mantles. A suitable framework for modelling this heat transport is a system including bottom heating (from the core) and internal heating, e.g., generated by secular cooling or by the decay of radioactive isotopes. The mechanism of heat transfer depends on the physical properties of the system. In systems where convection is able to operate, two different regimes are possible depending on the relative amount of bottom and internal heating. For moderate internal heating rates, the system is composed of active hot upwellings and cold downwellings. For large internal heating rates, the bottom heat flux becomes negative and the system is only composed of active cold downwellings. Here, we build theoretical scaling laws for both convective regimes following the approach of Vilella & Kaminski (2017), which links the surface heat flux and the temperature jump across both the top and bottom thermal boundary layer (TBL) to the Rayleigh number and the dimensionless internal heating rate. Theoretical predictions are then verified against numerical simulations performed in 2D and 3D-Cartesian geometry, and covering a large range of the parameter space. Our theoretical scaling laws are more successful in predicting the thermal structure of systems with large internal heating rates than that of systems with no or moderate internal heating. The differences between moderate and large internal heating rates are interpreted as differences in the mechanisms generating thermal instabilities. We identified three mechanisms: conductive growth of the TBL, instability impacting, and TBL erosion, the last two being present only for moderate internal heating rates, in which hot plumes are generated at the bottom of the system and are able to reach the surface. Finally, we apply our scaling laws to the evolution of the early Earth, proposing a new model for the cooling of the primordial magma ocean that reconciles geochemical observations and magma ocean dynamics.

Evolution. A case of system dynamics.

PubMed

Apáthy, Z

1990-01-01

It is contended that the Darwinian theory of evolution is merely a special case of the obsolete Newtonian paradigm. A modern vision of reality, consistent with structuralism in biology, is presented. Some well-known neo-Darwinist explanations of the evolutionary process are quoted accompanied by structuralist interpretations of the same cases. These lead to a different 'mechanism' of evolution, based on internal factors, consistent with contemporary science. It is argued that a great number of specialists who dismiss the Darwinian theory of evolution share a common reason for rejecting it, but differ widely in guessing the motivating factor or factors of evolution.

Large communications platforms versus smaller satellites

NASA Technical Reports Server (NTRS)

1979-01-01

Communications systems using large platforms are compared with systems using conventional satellites. Systems models were generated and compared for U.S. domestic application and for 1 INTELSAT's international and domestic transponder lease application. Technology advances were assumed the platforms and the evolution of conventional satellites.

The 1973 Smithsonian standard earth (3). [for the satellite geodesy program

NASA Technical Reports Server (NTRS)

Garoschkin, E. M. (Editor)

1973-01-01

The origins of the satellite geodesy program are described, starting with the International Geophysical Year, continuing through a number of international programs, and culminating with the National Geodetic Satellite Program. The philosophical basis for the Baker-Nunn camera and the laser ranging system, the evolution of international scientific cooperation, and the significance of the results are discussed.

Update on the genomics and basic biology of Brachypodium: International Brachypodium Initiative (IBI)

USDA-ARS?s Scientific Manuscript database

The scientific presentations at the First International Brachypodium Conference (abstracts available at www.brachy2013.unimore.it) are evidence of the widespread adoption of Brachypodium as a model system. Furthermore, the wide range of topics presented (genome evolution, roots, abiotic and biotic s...

About Tidal Evolution of Quasi-Periodic Orbits of Satellites

NASA Astrophysics Data System (ADS)

Ershkov, Sergey V.

2017-06-01

Tidal interactions between Planet and its satellites are known to be the main phenomena, which are determining the orbital evolution of the satellites. The modern ansatz in the theory of tidal dissipation in Saturn was developed previously by the international team of scientists from various countries in the field of celestial mechanics. Our applying to the theory of tidal dissipation concerns the investigating of the system of ODE-equations (ordinary differential equations) that govern the orbital evolution of the satellites; such an extremely non-linear system of 2 ordinary differential equations describes the mutual internal dynamics for the eccentricity of the orbit along with involving the semi-major axis of the proper satellite into such a monstrous equations. In our derivation, we have presented the elegant analytical solutions to the system above; so, the motivation of our ansatz is to transform the previously presented system of equations to the convenient form, in which the minimum of numerical calculations are required to obtain the final solutions. Preferably, it should be the analytical solutions; we have presented the solution as a set of quasi- periodic cycles via re-inversing of the proper ultra- elliptical integral. It means a quasi-periodic character of the evolution of the eccentricity, of the semi-major axis for the satellite orbit as well as of the quasi-periodic character of the tidal dissipation in the Planet.

The Rise of China in the International Trade Network: A Community Core Detection Approach

PubMed Central

Zhu, Zhen; Cerina, Federica; Chessa, Alessandro; Caldarelli, Guido; Riccaboni, Massimo

2014-01-01

Theory of complex networks proved successful in the description of a variety of complex systems ranging from biology to computer science and to economics and finance. Here we use network models to describe the evolution of a particular economic system, namely the International Trade Network (ITN). Previous studies often assume that globalization and regionalization in international trade are contradictory to each other. We re-examine the relationship between globalization and regionalization by viewing the international trade system as an interdependent complex network. We use the modularity optimization method to detect communities and community cores in the ITN during the years 1995–2011. We find rich dynamics over time both inter- and intra-communities. In particular, the Asia-Oceania community disappeared and reemerged over time along with a switch in leadership from Japan to China. We provide a multilevel description of the evolution of the network where the global dynamics (i.e., communities disappear or reemerge) and the regional dynamics (i.e., community core changes between community members) are related. Moreover, simulation results show that the global dynamics can be generated by a simple dynamic-edge-weight mechanism. PMID:25136895

The rise of China in the International Trade Network: a community core detection approach.

PubMed

Zhu, Zhen; Cerina, Federica; Chessa, Alessandro; Caldarelli, Guido; Riccaboni, Massimo

2014-01-01

Theory of complex networks proved successful in the description of a variety of complex systems ranging from biology to computer science and to economics and finance. Here we use network models to describe the evolution of a particular economic system, namely the International Trade Network (ITN). Previous studies often assume that globalization and regionalization in international trade are contradictory to each other. We re-examine the relationship between globalization and regionalization by viewing the international trade system as an interdependent complex network. We use the modularity optimization method to detect communities and community cores in the ITN during the years 1995-2011. We find rich dynamics over time both inter- and intra-communities. In particular, the Asia-Oceania community disappeared and reemerged over time along with a switch in leadership from Japan to China. We provide a multilevel description of the evolution of the network where the global dynamics (i.e., communities disappear or reemerge) and the regional dynamics (i.e., community core changes between community members) are related. Moreover, simulation results show that the global dynamics can be generated by a simple dynamic-edge-weight mechanism.

Functional Constructivism: In Search of Formal Descriptors.

PubMed

Trofimova, Irina

2017-10-01

The Functional Constructivism (FC) paradigm is an alternative to behaviorism and considers behavior as being generated every time anew, based on an individual's capacities, environmental resources and demands. Walter Freeman's work provided us with evidence supporting the FC principles. In this paper we make parallels between gradual construction processes leading to the formation of individual behavior and habits, and evolutionary processes leading to the establishment of biological systems. Referencing evolutionary theory, several formal descriptors of such processes are proposed. These FC descriptors refer to the most universal aspects for constructing consistent structures: expansion of degrees of freedom, integration processes based on internal and external compatibility between systems and maintenance processes, all given in four different classes of systems: (a) Zone of Proximate Development (poorly defined) systems; (b) peer systems with emerging reproduction of multiple siblings; (c) systems with internalized integration of behavioral elements ('cruise controls'); and (d) systems capable of handling low-probability, not yet present events. The recursive dynamics within this set of descriptors acting on (traditional) downward, upward and horizontal directions of evolution, is conceptualized as diagonal evolution, or di-evolution. Two examples applying these FC descriptors to taxonomy are given: classification of the functionality of neuro-transmitters and temperament traits; classification of mental disorders. The paper is an early step towards finding a formal language describing universal tendencies in highly diverse, complex and multi-level transient systems known in ecology and biology as 'contingency cycles.'

Proceedings of the 3rd International Workshop on a Research Agenda for Maintenance and Evolution of Service-Oriented Systems (MESOA 2009)

DTIC Science & Technology

2010-02-01

through software -as-a- service ( SaaS ) (Nitu 2009, Sedayao 2008). In practice, an organization’s initial SOA implementation almost never attempts to cover...004 Nitu. "Configurability in SaaS ( Software as a Service ) Applications." Proceedings of the 2nd An- nual Conference on India Software Engineering...and evolution of service -oriented systems. In 2007, the Software Engineering Institute started assembling a SOA Research Agenda based on a

The microviridae: Diversity, assembly, and experimental evolution.

PubMed

Doore, Sarah M; Fane, Bentley A

2016-04-01

The Microviridae, comprised of ssDNA, icosahedral bacteriophages, are a model system for studying morphogenesis and the evolution of assembly. Historically limited to the φX174-like viruses, recent results demonstrate that this richly diverse family is broadly divided into two groups. The defining feature appears to be whether one or two scaffolding proteins are required for assembly. The single-scaffolding systems contain an internal scaffolding protein, similar to many dsDNA viruses, and have a more complex coat protein fold. The two-scaffolding protein systems (φX174-like) encode an internal and external species, as well as an additional structural protein: a spike on the icosahedral vertices. Here, we discuss recent in silico and in vivo evolutionary analyses conducted with chimeric viruses and/or chimeric proteins. The results suggest 1) how double scaffolding systems can evolve into single and triple scaffolding systems; and 2) how assembly is the critical factor governing adaptation and the maintenance of species boundaries. Copyright © 2016 Elsevier Inc. All rights reserved.

Future NASA solar system exploration activities: A framework for international cooperation

NASA Technical Reports Server (NTRS)

French, Bevan M.; Ramlose, Terri; Briggs, Geoffrey A.

1992-01-01

The goals and approaches for planetary exploration as defined for the NASA Solar System Exploration Program are discussed. The evolution of the program since the formation of the Solar System Exploration Committee (SSEC) in 1980 is reviewed and the primary missions comprising the program are described.

Yinong Sun | NREL

Science.gov Websites

integration Impacts of climate change on energy system evolution Energy policy analysis Education M.E.M. in . Electric Sector Climate Impacts. International Energy Workshop, Maryland. View all NREL publications for

Tidal evolution in close binary systems.

NASA Technical Reports Server (NTRS)

Kopal, Z.

1972-01-01

Mathematical outline of the theory of tidal evolution in close binary systems of secularly constant total momentum. Following a general outline of the problem the basic expressions for the energy and momenta of close binaries consisting of components of arbitrary internal structure are established, and the maximum and minimum values of the energy (kinetic and potential) which such systems can attain for a given amount of total momentum are investigated. These results are compared with the actual facts encountered in binaries with components whose internal structure (and, therefore, rotational momenta) are known from evidence furnished by the observed rates of apsidal advance. The results show that all such systems whether of detached or semidetached type - disclose that more than 99% of their total momenta are stored in the orbital momentum. The sum of the rotational momenta of the constituent components amounts to less than 1% of the total -a situation characteristic of a state close to the minimum energy for given total momentum.

Principles of time evolution in classical physics

NASA Astrophysics Data System (ADS)

Güémez, J.; Fiolhais, M.

2018-07-01

We address principles of time evolution in classical mechanical/thermodynamical systems in translational and rotational motion, in three cases: when there is conservation of mechanical energy, when there is energy dissipation and when there is mechanical energy production. In the first case, the time derivative of the Hamiltonian vanishes. In the second one, when dissipative forces are present, the time evolution is governed by the minimum potential energy principle, or, equivalently, maximum increase of the entropy of the universe. Finally, in the third situation, when internal sources of work are available to the system, it evolves in time according to the principle of minimum Gibbs function. We apply the Lagrangian formulation to the systems, dealing with the non-conservative forces using restriction functions such as the Rayleigh dissipative function.

System Safety in Early Manned Space Program: A Case Study of NASA and Project Mercury

NASA Technical Reports Server (NTRS)

Hansen, Frederick D.; Pitts, Donald

2005-01-01

This case study provides a review of National Aeronautics and Space Administration s (NASA's) involvement in system safety during research and evolution from air breathing to exo-atmospheric capable flight systems culminating in the successful Project Mercury. Although NASA has been philosophically committed to the principals of system safety, this case study points out that budget and manpower constraints-as well as a variety of internal and external pressures can jeopardize even a well-designed system safety program. This study begins with a review of the evolution and early years of NASA's rise as a project lead agency and ends with the lessons learned from Project Mercury.

Helium Evolution from the Transfer of Helium Saturated Propellant in Space

NASA Technical Reports Server (NTRS)

Nguyen, Bich N.

2000-01-01

Helium evolution from the transfer of helium saturated propellant in space is quantified to determine its impact from creating a two-phase mixture in the transfer line. The transfer line is approximately 1/2 inch in diameter and 2400 inches in length comprised of the Fluid Interconnect System (FICS), the Orbiter Propellant Transfer System (OPTS) and the International Space Station (ISS) Propulsion Module (ISSPM). The propellant transfer rate is approximately two to three gallons per minute, and the supply tank pressure is maintained at approximately 250 psig.

(abstract) Towards Ancillary Data Standards

NASA Technical Reports Server (NTRS)

Acton, Charles H.

1997-01-01

NASA's SPICE information system for archiving, distributing, and accessing spacecraft navigation, orientation, and other ancillary data is described. A proposal is made for the further evolution of this concept to an internationally useful standard, to be.

Planning Systems for Distributed Operations

NASA Technical Reports Server (NTRS)

Maxwell, Theresa G.

2002-01-01

This viewgraph representation presents an overview of the mission planning process involving distributed operations (such as the International Space Station (ISS)) and the computer hardware and software systems needed to support such an effort. Topics considered include: evolution of distributed planning systems, ISS distributed planning, the Payload Planning System (PPS), future developments in distributed planning systems, Request Oriented Scheduling Engine (ROSE) and Next Generation distributed planning systems.

The evolution of spinal instrumentation for the management of occipital cervical and cervicothoracic junctional injuries.

PubMed

Smucker, Joseph D; Sasso, Rick C

2006-05-15

Independent computer-based literature review of articles pertaining to instrumentation and fusion of junctional injuries of the cervical spine. To review and discuss the evolution of instrumentation techniques and systems used in the treatment of cervical spine junctional injuries. Instrumentation of junctional injuries of the cervical spine has been limited historically by failure to achieve rigid internal fixation in multiple planes. The evolution of these techniques has required increased insight into the morphology and unique biomechanics of the structures to be instrumented. Computer-based literature search of Ovid and PubMed databases. Extensive literature search yielded insights into the evolution of systems initially based on onlay bone graft combined with wiring techniques. Such techniques have come to include systems incorporating rigid, longitudinal struts that accommodate multiplanar screws placed in the lateral masses, pedicles, transarticular regions, and occipital bone. Despite a rapid evolution of techniques and instrumentation technologies, it remains incumbent on the physician to provide the patient with a surgical procedure that balances the likelihood of a favorable outcome with the risk inherent in the implementation of the procedure.

Scaling and Thermal Evolution of Internally Heated Planets: Yield Stress and Thermal History.

NASA Astrophysics Data System (ADS)

Weller, M. B.; Lenardic, A.; Moore, W. B.

2014-12-01

Using coupled 3D mantle convection and planetary tectonics models of bi-stable systems, we show how system behaviors for mobile-lid and stagnant-lid states scale as functions of internal heating rates (Q) and basal Ra (Rab). With parameter ranges for temperature- and depth-dependant viscosities: 1e4 - 3e4, Rab: 1e5- 3e5, Q: 0 - 100, and yield stress: 1e4 - 2e5, it can be shown the internal temperatures, velocities, heat fluxes, and system behaviors for mobile-lid and stagnant-lid states diverge, for equivalent parameter values, as a function of increasing Q. For the mobile-lid regime, yielding behavior in the upper boundary layer strongly influences the dynamics of the system. Internal temperatures, and consequently temperature-dependant viscosities, vary strongly as a function of yield stress for a given Q. The temperature distribution across the upper and lower mantles are sub-adiabatic for low to moderate yield stress, and adiabatic to super-adiabatic for high yield stresses. Across the parameter range considered, and for fixed yield stress, the Nu across the basal boundary (Nub) is positive and only weakly dependant on Q (varies by ~ 9%). Nub varies strongly as a function of yield stress (maximum variation of ~84%). Both mobile-lid velocities and lid-thicknesses are yield stress dependant for a given Q and Ra. In contrast to mobile-lids, the stagnant-lid regime is governed by the relative inefficiency of heat transport through the surface boundary layer. Internal temperatures are yield stress independent, and are on average 30% greater. Nub has a strong dependence on heating rates and surface boundary layer thicknesses. Within the parameter space considered, the maximum stagnant-lid Nub corresponds to the minimum mobile-lid Nub (for high yield stress), and decreases with increasing Q. For high Q, super-heated stagnant-lids may develop, with Nub< 0, and changes in trends for system behaviors. Planets with high levels of internal heating and/or high yield stresses (e.g. Super-Earths), may favor super-heated stagnant-lids early in their evolution. These regimes indicate reduced heat transport efficiencies (from the nominal stagnant-lid), and as a result, increasing heat flux into the core with increasing Q. Implications for terrestrial and Super-Earth planetary evolution will be discussed.

ISSOL Meeting, 7th, Barcelona, Spain, July 4-9, 1993. [Abstracts only

NASA Technical Reports Server (NTRS)

Ferris, James P. (Editor)

1994-01-01

The journal issue consists of abstracts presented at the International Society for the Study of the Origins of Life (ISSOL) conference. Topics include research on biological and chemical evolution including prebiotic evolution: cosmic and terrestrial; mechanisms of abiogenesis including synthesis and reactions of biomonomers; and analysis of cometary matter and its possible relationship to organic compounds on Earth. Theories and research on origins of ribonucleic acids (RNA), deoxyribonucleic acid (DNA), and other amino acids and complex proteins including their autocatalysis, replication, and translation are presented. Abiotic synthesis of biopolymers, mechanisms of the Genetic Code, precellular membrane systems and energetics are considered. Earth planetary evolution including early microfossils and geochemical conditions and simulations to study these conditions are discussed. The role of chirality in precellular evolution and the taxonomy and phylogeny of very simple organisms are reported. Past and future explorations in exobiology and space research directed toward study of the origins of life and solar system evolution are described.

Close binary evolution. II. Impact of tides, wind magnetic braking, and internal angular momentum transport

NASA Astrophysics Data System (ADS)

Song, H. F.; Meynet, G.; Maeder, A.; Ekström, S.; Eggenberger, P.; Georgy, C.; Qin, Y.; Fragos, T.; Soerensen, M.; Barblan, F.; Wade, G. A.

2018-01-01

Context. Massive stars with solar metallicity lose important amounts of rotational angular momentum through their winds. When a magnetic field is present at the surface of a star, efficient angular momentum losses can still be achieved even when the mass-loss rate is very modest, at lower metallicities, or for lower-initial-mass stars. In a close binary system, the effect of wind magnetic braking also interacts with the influence of tides, resulting in a complex evolution of rotation. Aims: We study the interactions between the process of wind magnetic braking and tides in close binary systems. Methods: We discuss the evolution of a 10 M⊙ star in a close binary system with a 7 M⊙ companion using the Geneva stellar evolution code. The initial orbital period is 1.2 days. The 10 M⊙ star has a surface magnetic field of 1 kG. Various initial rotations are considered. We use two different approaches for the internal angular momentum transport. In one of them, angular momentum is transported by shear and meridional currents. In the other, a strong internal magnetic field imposes nearly perfect solid-body rotation. The evolution of the primary is computed until the first mass-transfer episode occurs. The cases of different values for the magnetic fields and for various orbital periods and mass ratios are briefly discussed. Results: We show that, independently of the initial rotation rate of the primary and the efficiency of the internal angular momentum transport, the surface rotation of the primary will converge, in a time that is short with respect to the main-sequence lifetime, towards a slowly evolving velocity that is different from the synchronization velocity. This "equilibrium angular velocity" is always inferior to the angular orbital velocity. In a given close binary system at this equilibrium stage, the difference between the spin and the orbital angular velocities becomes larger when the mass losses and/or the surface magnetic field increase. The treatment of the internal angular momentum transport has a strong impact on the evolutionary tracks in the Hertzsprung-Russell Diagram as well as on the changes of the surface abundances resulting from rotational mixing. Our modelling suggests that the presence of an undetected close companion might explain rapidly rotating stars with strong surface magnetic fields, having ages well above the magnetic braking timescale. Our models predict that the rotation of most stars of this type increases as a function of time, except for a first initial phase in spin-down systems. The measure of their surface abundances, together, when possible, with their mass-luminosity ratio, provide interesting constraints on the transport efficiencies of angular momentum and chemical species. Conclusions: Close binaries, when studied at phases predating any mass transfer, are key objects to probe the physics of rotation and magnetic fields in stars.

Extended evolution: A conceptual framework for integrating regulatory networks and niche construction

PubMed Central

Renn, Jürgen

2015-01-01

ABSTRACT This paper introduces a conceptual framework for the evolution of complex systems based on the integration of regulatory network and niche construction theories. It is designed to apply equally to cases of biological, social and cultural evolution. Within the conceptual framework we focus especially on the transformation of complex networks through the linked processes of externalization and internalization of causal factors between regulatory networks and their corresponding niches and argue that these are an important part of evolutionary explanations. This conceptual framework extends previous evolutionary models and focuses on several challenges, such as the path‐dependent nature of evolutionary change, the dynamics of evolutionary innovation and the expansion of inheritance systems. J. Exp. Zool. (Mol. Dev. Evol.) 324B: 565–577, 2015. © 2015 The Authors. Journal of Experimental Zoology Part B: Molecular and Developmental Evolution published by Wiley Periodicals, Inc. PMID:26097188

An option space for early neural evolution.

PubMed

Jékely, Gáspár; Keijzer, Fred; Godfrey-Smith, Peter

2015-12-19

The origin of nervous systems has traditionally been discussed within two conceptual frameworks. Input-output models stress the sensory-motor aspects of nervous systems, while internal coordination models emphasize the role of nervous systems in coordinating multicellular activity, especially muscle-based motility. Here we consider both frameworks and apply them to describe aspects of each of three main groups of phenomena that nervous systems control: behaviour, physiology and development. We argue that both frameworks and all three aspects of nervous system function need to be considered for a comprehensive discussion of nervous system origins. This broad mapping of the option space enables an overview of the many influences and constraints that may have played a role in the evolution of the first nervous systems. © 2015 The Author(s).

A Coupled Modeling Framework of the Co-evolution of Humans and Water: Case Study of Tarim River Basin, Western China

NASA Astrophysics Data System (ADS)

Liu, D.; Tian, F.; Lin, M.; Sivapalan, M.

2014-12-01

The complex interactions and feedbacks between humans and water are very essential issues but are poorly understood in the newly proposed discipline of socio-hydrology (Sivapalan et al., 2012). An exploratory model with the appropriate level of simplification can be valuable to improve our understanding of the co-evolution and self-organization of socio-hydrological systems driven by interactions and feedbacks operating at different scales. In this study, a simple coupled modeling framework for socio-hydrology co-evolution is developed for the Tarim River Basin in Western China, and is used to illustrate the explanatory power of such a model. The study area is the mainstream of the Tarim River, which is divided into two modeling units. The socio-hydrological system is composed of four parts, i.e., social sub-system, economic sub-system, ecological sub-system, and hydrological sub-system. In each modeling unit, four coupled ordinary differential equations are used to simulate the dynamics of the social sub-system represented by human population, the economic sub-system represented by irrigated crop area, the ecological sub-system represented by natural vegetation cover and the hydrological sub-system represented by stream discharge. The coupling and feedback processes of the four dominant sub-systems (and correspondingly four state variables) are integrated into several internal system characteristics interactively and jointly determined by themselves and by other coupled systems. For example, the stream discharge is coupled to the irrigated crop area by the colonization rate and mortality rate of the irrigated crop area in the upper reach and the irrigated area is coupled to stream discharge through irrigation water consumption. The co-evolution of the Tarim socio-hydrological system is then analyzed within this modeling framework to gain insights into the overall system dynamics and its sensitivity to the external drivers and internal system variables. In the modeling framework, the state of each subsystem is holistically described by one state variable and the framework is flexible enough to comprise more processes and constitutive relationships if they are needed to illustrate the interaction and feedback mechanisms of the human-water system.

Inferring internal properties of Earth's core dynamics and their evolution from surface observations and a numerical geodynamo model

NASA Astrophysics Data System (ADS)

Aubert, J.; Fournier, A.

2011-10-01

Over the past decades, direct three-dimensional numerical modelling has been successfully used to reproduce the main features of the geodynamo. Here we report on efforts to solve the associated inverse problem, aiming at inferring the underlying properties of the system from the sole knowledge of surface observations and the first principle dynamical equations describing the convective dynamo. To this end we rely on twin experiments. A reference model time sequence is first produced and used to generate synthetic data, restricted here to the large-scale component of the magnetic field and its rate of change at the outer boundary. Starting from a different initial condition, a second sequence is next run and attempts are made to recover the internal magnetic, velocity and buoyancy anomaly fields from the sparse surficial data. In order to reduce the vast underdetermination of this problem, we use stochastic inversion, a linear estimation method determining the most likely internal state compatible with the observations and some prior knowledge, and we also implement a sequential evolution algorithm in order to invert time-dependent surface observations. The prior is the multivariate statistics of the numerical model, which are directly computed from a large number of snapshots stored during a preliminary direct run. The statistics display strong correlation between different harmonic degrees of the surface observations and internal fields, provided they share the same harmonic order, a natural consequence of the linear coupling of the governing dynamical equations and of the leading influence of the Coriolis force. Synthetic experiments performed with a weakly nonlinear model yield an excellent quantitative retrieval of the internal structure. In contrast, the use of a strongly nonlinear (and more realistic) model results in less accurate static estimations, which in turn fail to constrain the unobserved small scales in the time integration of the evolution scheme. Evaluating the quality of forecasts of the system evolution against the reference solution, we show that our scheme can improve predictions based on linear extrapolations on forecast horizons shorter than the system e-folding time. Still, in the perspective of forthcoming data assimilation activities, our study underlines the need of advanced estimation techniques able to cope with the moderate to strong nonlinearities present in the geodynamo.

Eighth international congress on nitrogen fixation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1990-01-01

This volume contains the proceedings of the Eighth International Congress on Nitrogen Fixation held May 20--26, 1990 in Knoxville, Tennessee. The volume contains abstracts of individual presentations. Sessions were entitled Recent Advances in the Chemistry of Nitrogen Fixation, Plant-microbe Interactions, Limiting Factors of Nitrogen Fixation, Nitrogen Fixation and the Environment, Bacterial Systems, Nitrogen Fixation in Agriculture and Industry, Plant Function, and Nitrogen Fixation and Evolution.

Eighth international congress on nitrogen fixation. Final program

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1990-12-31

This volume contains the proceedings of the Eighth International Congress on Nitrogen Fixation held May 20--26, 1990 in Knoxville, Tennessee. The volume contains abstracts of individual presentations. Sessions were entitled Recent Advances in the Chemistry of Nitrogen Fixation, Plant-microbe Interactions, Limiting Factors of Nitrogen Fixation, Nitrogen Fixation and the Environment, Bacterial Systems, Nitrogen Fixation in Agriculture and Industry, Plant Function, and Nitrogen Fixation and Evolution.

Self-organization and complexity in historical landscape patterns

Treesearch

Janine Bolliger; Julien C. Sprott; David J. Mladenoff

2003-01-01

Self-organization describes the evolution process of complex structures where systems emerge spontaneously, driven internally by variations of the system itself. Self-organization to the critical state is manifested by scale-free behavior across many orders of magnitude (Bak et al. 1987, Bak 1996, Sole et a1. 1999). Spatial scale-free behavior implies fractal...

Environmental Factors Affecting Computer Assisted Language Learning Success: A Complex Dynamic Systems Conceptual Model

ERIC Educational Resources Information Center

Marek, Michael W.; Wu, Wen-Chi Vivian

2014-01-01

This conceptual, interdisciplinary inquiry explores Complex Dynamic Systems as the concept relates to the internal and external environmental factors affecting computer assisted language learning (CALL). Based on the results obtained by de Rosnay ["World Futures: The Journal of General Evolution", 67(4/5), 304-315 (2011)], who observed…

Language Program as Ecology: A Perspective for Leadership

ERIC Educational Resources Information Center

Pennington, Martha C.; Hoekje, Barbara J.

2010-01-01

A language program is a delicate and intricate system of interacting resources or components, which, like a biological ecology, is in a constant state of evolution and change. The interactive system making up the program's internal culture is connected ecologically to the external environment. The ecological model is introduced as a useful…

Opening Up "Open Systems": Moving toward True Interoperability among Library Software. DataResearch Automation Guide Series, Number One.

ERIC Educational Resources Information Center

Data Research Associates, Inc., St. Louis, MO.

The topic of open systems as it relates to the needs of libraries to establish interoperability between dissimilar computer systems can be clarified by an understanding of the background and evolution of the issue. The International Standards Organization developed a model to link dissimilar computers, and this model has evolved into consensus…

Integrating Information Systems in a Major Decentralized International Organization. Volume 7.

DTIC Science & Technology

1987-12-01

deployment of information technology. Three key conflicting organizational forces were found to significantly impact the technical strategies : 1... strategy was modulated by three key conflicting organizational forces - autonomy, integration and evolution. A conceptual system architecture has been... organizational needs. The second part, "Gaining Strategic Advantage Through Composite Tnformation Systems," identifies critical success factors for the

Effects of Dynamical Evolution on Globular Clusters’ Internal Kinematics

NASA Astrophysics Data System (ADS)

Tiongco, Maria; Vesperini, Enrico; Varri, Anna Lisa

2018-01-01

The synergy between recent photometric, spectroscopic, and astrometric studies is revealing that globular clusters deviate from the traditional picture of dynamically simple and single stellar population systems. Complex kinematical features such as velocity anisotropy and rotation, and the existence of multiple stellar populations are some of the key observational findings. My thesis work has aimed to build a theoretical framework to interpret these new observational results and to understand their link with a globular cluster’s dynamical history.I have focused on the study of the evolution of globular clusters' internal kinematics, as driven by two-body relaxation, and the interplay between internal angular momentum and the external Galactic tidal field. With a specifically-designed, large survey of direct N-body simulations, I have explored the three-dimensional structure of the velocity space of tidally-perturbed clusters, by characterizing their degree of anisotropy and their rotational properties. These studies have proved that a cluster's kinematical properties contain a distinct imprints of the cluster’s initial structural properties, dynamical history, and tidal environment. By relaxing a number of simplifying assumptions that are traditionally imposed, I have also showed how the interplay between a cluster's internal evolution and the interaction with the host galaxy can produce complex morphological and kinematical properties, such as a counter-rotating core and a twisting of the projected isodensity contours.Building on this fundamental understanding, I have then studied the dynamics of multiple stellar populations in globular clusters, with attention to the largely unexplored role of angular momentum. I have analyzed the evolution of clusters with stellar populations characterized by different initial structural and kinematical properties to determine how long these differences are preserved, and in what cases they could still be observable in present-day systems.This body of results provides essential guidance for a meaningful interpretation of the emerging dynamical complexity of globular clusters in the era of Gaia and other upcoming large spectroscopic surveys.

An Effective Continuum Model for the Gas Evolution in Internal Steam Drives

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsimpanogiannis, Ioannis N.; Yortsos, Yanis C.

This report examines the gas phase growth from a supersaturated, slightly compressible, liquid in a porous medium, driven by heat transfer and controlled by the application of a constant-rate decline of the system pressure.

Chaos and the (un)predictability of evolution in a changing environment.

PubMed

Rego-Costa, Artur; Débarre, Florence; Chevin, Luis-Miguel

2018-02-01

Among the factors that may reduce the predictability of evolution, chaos, characterized by a strong dependence on initial conditions, has received much less attention than randomness due to genetic drift or environmental stochasticity. It was recently shown that chaos in phenotypic evolution arises commonly under frequency-dependent selection caused by competitive interactions mediated by many traits. This result has been used to argue that chaos should often make evolutionary dynamics unpredictable. However, populations also evolve largely in response to external changing environments, and such environmental forcing is likely to influence the outcome of evolution in systems prone to chaos. We investigate how a changing environment causing oscillations of an optimal phenotype interacts with the internal dynamics of an eco-evolutionary system that would be chaotic in a constant environment. We show that strong environmental forcing can improve the predictability of evolution by reducing the probability of chaos arising, and by dampening the magnitude of chaotic oscillations. In contrast, weak forcing can increase the probability of chaos, but it also causes evolutionary trajectories to track the environment more closely. Overall, our results indicate that, although chaos may occur in evolution, it does not necessarily undermine its predictability. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

Evolution of Education for International Mindedness

ERIC Educational Resources Information Center

Hill, Ian

2012-01-01

This article attempts to trace the evolution of the concept of international mindedness from the 17th century until the present, using four aspects to focus the discussion: education and other trends, ease of interaction across frontiers, determinants of international mindedness, and international mindedness in practice. Education trends start…

Progress in Development of the ITER Plasma Control System Simulation Platform

NASA Astrophysics Data System (ADS)

Walker, Michael; Humphreys, David; Sammuli, Brian; Ambrosino, Giuseppe; de Tommasi, Gianmaria; Mattei, Massimiliano; Raupp, Gerhard; Treutterer, Wolfgang; Winter, Axel

2017-10-01

We report on progress made and expected uses of the Plasma Control System Simulation Platform (PCSSP), the primary test environment for development of the ITER Plasma Control System (PCS). PCSSP will be used for verification and validation of the ITER PCS Final Design for First Plasma, to be completed in 2020. We discuss the objectives of PCSSP, its overall structure, selected features, application to existing devices, and expected evolution over the lifetime of the ITER PCS. We describe an archiving solution for simulation results, methods for incorporating physics models of the plasma and physical plant (tokamak, actuator, and diagnostic systems) into PCSSP, and defining characteristics of models suitable for a plasma control development environment such as PCSSP. Applications of PCSSP simulation models including resistive plasma equilibrium evolution are demonstrated. PCSSP development supported by ITER Organization under ITER/CTS/6000000037. Resistive evolution code developed under General Atomics' Internal funding. The views and opinions expressed herein do not necessarily reflect those of the ITER Organization.

Corrections to chance fluctuations: quantum mind in biological evolution?

PubMed

Damiani, Giuseppe

2009-01-01

According to neo-Darwinian theory, biological evolution is produced by natural selection of random hereditary variations. This assumption stems from the idea of a mechanical and deterministic world based on the laws of classic physics. However, the increased knowledge of relationships between metabolism, epigenetic systems, and editing of nucleic acids suggests the existence of self-organized processes of adaptive evolution in response to environmental stresses. Living organisms are open thermodynamic systems which use entropic decay of external source of electromagnetic energy to increase their internal dynamic order and to generate new genetic and epigenetic information with a high degree of coherency and teleonomic creativity. Sensing, information processing, and decision making of biological systems might be mainly quantum phenomena. Amplification of microscopic quantum events using the long-range correlation of fractal structures, at the borderline between deterministic order and unpredictable chaos, may be used to direct a reproducible transition of the biological systems towards a defined macroscopic state. The discoveries of many natural genetic engineering systems, the ability to choose the most effective solutions, and the emergence of complex forms of consciousness at different levels confirm the importance of mind-action directed processes in biological evolution, as suggested by Alfred Russel Wallace. Although the main Darwinian principles will remain a crucial component of our understanding of evolution, a radical rethinking of the conceptual structure of the neo-Darwinian theory is needed.

International review of cytology. Volume 106. A survey of cell biology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bourne, G.H.; Jeon, K.W.; Friedlander, M.

1987-01-01

Contents: Morphology and Cytochemistry of the Endocrine Epthelial System in the Lung; Intrinsic Nerve Plexus of Mammalian Heart; Morphological Basis of Cardiac Rhythmical Activity. Structural and Functional Evolution of Gonadotropin-Releasing Hormone; Excitons and Solitons in Molecular Systems; The Centrosome and Its Role in the Organization of Microtubules. Each chapter includes references. Index.

A Conversational Mass Spectral Search System. IV. The Evolution of a System for the Retrieval of Mass Spectral Information

ERIC Educational Resources Information Center

Heller, Stephen R.; And Others

1973-01-01

A prototype of an interactive, conversational mass spectral search system, developed at the National Institutes of Health, has been tested since September 1971 and is now being used by more than 200 scientists in the U.S. and Canada, and will soon be used by the international mass spectrometry community. (17 references) (SJ)

Dynamical Asteroseismology: towards improving the theories of stellar structure and (tidal) evolution

NASA Astrophysics Data System (ADS)

Tkachenko, Andrew

2017-10-01

The potential of the dynamical asteroseismology, the research area that builds upon the synergies between the asteroseismology and binary stars research fields, is discussed in this manuscript. We touch upon the following topics: i) the mass discrepancy observed in intermediate-to high-mass main-sequence and evolved binaries as well as in the low mass systems that are still in the pre-main sequence phase of their evolution; ii) the rotationally induced mixing in high-mass stars, in particular how the most recent theoretical predictions and spectroscopic findings compare to the results of asteroseismic investigations; iii) internal gravity waves and their potential role in the evolution of binary star systems and surface nitrogen enrichment in high-mass stars; iv) the tidal evolution theory, in particular how its predictions of spin-orbit synchronisation and orbital circularisation compare to the present-day high-quality observations; v) the tidally-induced pulsations and their role in the angular momentum transport within binary star systems; vi) the scaling relations between fundamental and seismic properties of stars across the entire HR-diagram.

Parametric study on kink instabilities of twisted magnetic flux ropes in the solar atmosphere

NASA Astrophysics Data System (ADS)

Mei, Z. X.; Keppens, R.; Roussev, I. I.; Lin, J.

2018-01-01

Aims: Twisted magnetic flux ropes (MFRs) in the solar atmosphere have been researched extensively because of their close connection to many solar eruptive phenomena, such as flares, filaments, and coronal mass ejections (CMEs). In this work, we performed a set of 3D isothermal magnetohydrodynamic (MHD) numerical simulations, which use analytical twisted MFR models and study dynamical processes parametrically inside and around current-carrying twisted loops. We aim to generalize earlier findings by applying finite plasma β conditions. Methods: Inside the MFR, approximate internal equilibrium is obtained by pressure from gas and toroidal magnetic fields to maintain balance with the poloidal magnetic field. We selected parameter values to isolate best either internal or external kink instability before studying complex evolutions with mixed characteristics. We studied kink instabilities and magnetic reconnection in MFRs with low and high twists. Results: The curvature of MFRs is responsible for a tire tube force due to its internal plasma pressure, which tends to expand the MFR. The curvature effect of toroidal field inside the MFR leads to a downward movement toward the photosphere. We obtain an approximate internal equilibrium using the opposing characteristics of these two forces. A typical external kink instability totally dominates the evolution of MFR with infinite twist turns. Because of line-tied conditions and the curvature, the central MFR region loses its external equilibrium and erupts outward. We emphasize the possible role of two different kink instabilities during the MFR evolution: internal and external kink. The external kink is due to the violation of the Kruskal-Shafranov condition, while the internal kink requires a safety factor q = 1 surface inside the MFR. We show that in mixed scenarios, where both instabilities compete, complex evolutions occur owing to reconnections around and within the MFR. The S-shaped structures in current distributions appear naturally without invoking flux emergence. Magnetic reconfigurations common to eruptive MFRs and flare loop systems are found in our simulations.

Chaos and the (un)predictability of evolution in a changing environment

PubMed Central

Rego-Costa, Artur; Débarre, Florence; Chevin, Luis-Miguel

2018-01-01

Among the factors that may reduce the predictability of evolution, chaos, characterized by a strong dependence on initial conditions, has received much less attention than randomness due to genetic drift or environmental stochasticity. It was recently shown that chaos in phenotypic evolution arises commonly under frequency-dependent selection caused by competitive interactions mediated by many traits. This result has been used to argue that chaos should often make evolutionary dynamics unpredictable. However, populations also evolve largely in response to external changing environments, and such environmental forcing is likely to influence the outcome of evolution in systems prone to chaos. We investigate how a changing environment causing oscillations of an optimal phenotype interacts with the internal dynamics of an eco-evolutionary system that would be chaotic in a constant environment. We show that strong environmental forcing can improve the predictability of evolution, by reducing the probability of chaos arising, and by dampening the magnitude of chaotic oscillations. In contrast, weak forcing can increase the probability of chaos, but it also causes evolutionary trajectories to track the environment more closely. Overall, our results indicate that, although chaos may occur in evolution, it does not necessarily undermine its predictability. PMID:29235104

Management of the diffusion of 4-methylumbelliferone across phases in microdroplet-based systems for in vitro protein evolution.

PubMed

Wu, Nan; Courtois, Fabienne; Zhu, Yonggang; Oakeshott, John; Easton, Chris; Abell, Chris

2010-09-01

Fluorongenic reagents based on 4-methylumbelliferone (4-MU) have been widely used for the detection of phosphatase, sulfatase, esterase, lipase and glycosidase activities in conventionally formatted enzyme assay systems. However, the sensitivity of assays based on these substrates is also potentially very useful in the microdroplet formats now being developed for high throughput in vitro evolution experiments. In this article, we report the investigation of diffusion of 4-MU as a model dye from water-in-oil droplets and the internal aqueous phase of water-in-oil-in-water droplets in microfluidics. The effect of BSA in the aqueous phase on the diffusion of 4-MU is also discussed. Based on these results, we provided here proof-of-concept of the reaction of the enzyme OpdA with the substrate coumaphos in water-in-oil-in-water droplets. In this double-emulsion system, the reaction of OpdA and coumaphos was achieved by allowing coumaphos to diffuse from the continuous aqueous phase across the oil phase into the internal aqueous droplets.

Generation and Evolution of Internal Waves in Luzon Strait

DTIC Science & Technology

2016-03-01

1 DISTRIBUTION STATEMENT A: Distribution approved for public release; distribution is unlimited. Generation and Evolution of Internal Waves in...internal tides, inertial waves , nonlinear internal waves (NLIWs), and turbulence mixing––in the ocean and thereby help develop improved parameterizations of...mixing for ocean models. Mixing within the stratified ocean is a particular focus as the complex interplay of internal waves from a variety of

The Evolution of the International System: Surrender Sovereignty or Fight to the Death

DTIC Science & Technology

2011-06-01

8 Robert Wright, Nonzero: The Logic of Human Destiny (New York, NY: First Vintage Books, 2001), 6-7. 9 Kenneth...systems, ecologies, cells, developing embryos , and ant colonies‖ as well as any socially constructed human group.36 Each system is made up of agents...Arnold. Discord and Collaboration. Baltimore, MD: The Johns Hopkins University Press, 1962. Wright, Robert. Nonzero: The Logic of Human Destiny

Structure and function of a compound eye, more than half a billion years old.

PubMed

Schoenemann, Brigitte; Pärnaste, Helje; Clarkson, Euan N K

2017-12-19

Until now, the fossil record has not been capable of revealing any details of the mechanisms of complex vision at the beginning of metazoan evolution. Here, we describe functional units, at a cellular level, of a compound eye from the base of the Cambrian, more than half a billion years old. Remains of early Cambrian arthropods showed the external lattices of enormous compound eyes, but not the internal structures or anything about how those compound eyes may have functioned. In a phosphatized trilobite eye from the lower Cambrian of the Baltic, we found lithified remnants of cellular systems, typical of a modern focal apposition eye, similar to those of a bee or dragonfly. This shows that sophisticated eyes already existed at the beginning of the fossil record of higher organisms, while the differences between the ancient system and the internal structures of a modern apposition compound eye open important insights into the evolution of vision. Copyright © 2017 the Author(s). Published by PNAS.

The Open Education System, Anadolu University, Turkey: E-Transformation in a Mega-University

ERIC Educational Resources Information Center

Latchem, Colin; Ozkul, Ali Ekrem; Aydin, Cengiz Hakan; Mutlu, Mehmet Emin

2006-01-01

Anadolu University in Turkey is one of the world's largest and least known mega-universities. Well over one million students in Turkey, the European Union and Northern Cyprus are enrolled in its Open Education System and yet few accounts of this dual-mode provider appear in the international literature. This article describes the evolution of the…

Beyond business process redesign: redefining Baxter's business network.

PubMed

Short, J E; Venkatraman, N

1992-01-01

Business process redesign has focused almost exclusively on improving the firm's internal operations. Although internal efficiency and effectiveness are important objectives, the authors argue that business network redesign--reconceptualizing the role of the firm and its key business processes in the larger business network--is of greater strategic importance. To support their argument, they analyze the evolution of Baxter's ASAP system, one of the most publicized but inadequately understood strategic information systems of the 1980s. They conclude by examining whether ASAP's early successes have positioned the firm well for the changing hospital supplies marketplace of the 1990s.

Evolutionary paths of binaries with a neutron star. I. The case of SAX J1808.4-3658

NASA Astrophysics Data System (ADS)

Tailo, M.; D'Antona, F.; Burderi, L.; Ventura, P.; di Salvo, T.; Sanna, A.; Papitto, A.; Riggio, A.; Maselli, A.

2018-06-01

The evolutionary status of the low mass X-ray binary SAX J1808.4-3658 is simulated by following the binary evolution of its possible progenitor system through mass transfer, starting at a period of ˜6.6 hr. The evolution includes angular momentum losses via magnetic braking and gravitational radiation. It also takes into account the effects of illumination of the donor by both the X-ray emission and the spin down luminosity of the pulsar. The system goes through stages of mass transfer and stages during which it is detached, where only the rotationally powered pulsar irradiates the donor. We show that the pulsar irradiation is a necessary ingredient to reach SAX J1808.4-3658 orbital period when the donor mass is reduced to 0.04-0.06 M⊙. We also show that the models reproduce important properties of the system, including the orbital period derivative, which is shown to be directly linked to the evolution through mass transfer cycles. Moreover we find that the effects of the irradiation on the internal structure of the donor are non negligible, causing the companion star to be non completely convective at the values of mass observed for the system and significantly altering its long term evolution, as the magnetic braking remains active along the whole evolution.

Evolution of Requirements and Assumptions for Future Exploration Missions

NASA Technical Reports Server (NTRS)

Anderson, Molly; Sargusingh, Miriam; Perry, Jay

2017-01-01

NASA programs are maturing technologies, systems, and architectures to enabling future exploration missions. To increase fidelity as technologies mature, developers must make assumptions that represent the requirements of a future program. Multiple efforts have begun to define these requirements, including team internal assumptions, planning system integration for early demonstrations, and discussions between international partners planning future collaborations. For many detailed life support system requirements, existing NASA documents set limits of acceptable values, but a future vehicle may be constrained in other ways, and select a limited range of conditions. Other requirements are effectively set by interfaces or operations, and may be different for the same technology depending on whether the hard-ware is a demonstration system on the International Space Station, or a critical component of a future vehicle. This paper highlights key assumptions representing potential life support requirements and explanations of the driving scenarios, constraints, or other issues that drive them.

The use of multi-channel ground penetrating radar and stream monitoring to investigate the seasonal evolution of englacial and subglacial drainage systems at the terminus of Exit Glacier, Alaska

NASA Astrophysics Data System (ADS)

Kilgore, Susan Marlena

Concerns regarding the issue of climate change and, in particular, the rapid retreat of glaciers around the world, have placed great importance on glacial monitoring. Some of the methods most commonly used to observe glacial change---direct mass balance measurements and remote sensing---provide valuable information about glacier change. However, these methods do not address the englacial and subglacial environments. Surface meltwater that enters englacial and subglacial hydrological networks can contribute to acceleration of ice flow, increased calving on marine-terminating glaciers, surges or outburst floods, and greater overall ablation rates. Because subsurface drainage systems often freeze during the winter and re-form each summer, examining the seasonal evolution of these networks is crucial for assessing the impact that internal drainage may have on the behavior of a glacier each year. The goal of this study is to determine the role englacial and subglacial drainage system evolution plays in influencing summer ablation and discharge at the terminus of Exit Glacier, a small valley glacier located in South-central Alaska. During the summers of 2010 and 2011, we used ground-penetrating radar (GPR) to locate internal drainage features on the lower 100 meters of the glacier. GPR surveys were conducted in June and August of each year in an effort to observe the evolution of the drainage systems over the course of an ablation season. Three antenna frequencies---250, 500, and 800 MHz---were used on a dual frequency GPR so that various resolutions and depths in the ice could be viewed simultaneously. Stream monitoring was conducted to document discharge in the proglacial stream throughout the 2011 season. These data were compared with weather records to differentiate noticeable meltwater releases from precipitation events. Additionally, morphological changes in the glacier were observed through photographic documentation. Throughout the observation period, significant subglacial tunnels appeared, followed by the collapse of terminal ice above the tunnels. This phenomenon was most noticeable in 2011. These observations indicate that the internal drainage systems near the terminus of Exit Glacier became very well-developed each summer, and contributed approximately 75 meters of ice loss between June, 2010 and August, 2011.

Evolution of the social network of scientific collaborations

NASA Astrophysics Data System (ADS)

Barabasi, Albert-Laszlo; Jeong, Hawoong; Neda, Zoltan; Ravasz, Erzsebet; Schubert, Andras; Vicsek, Tamas

2002-03-01

The co-authorship network of scientists represents a prototype of complex evolving networks. By mapping the electronic database containing all relevant journals in mathematics and neuro-science for an eight-year period (1991-98), we infer the dynamic and the structural mechanisms that govern the evolution and topology of this complex system. First, empirical measurements allow us to uncover the topological measures that characterize the network at a given moment, as well as the time evolution of these quantities. The results indicate that the network is scale-free, and that the network evolution is governed by preferential attachment, affecting both internal and external links. However, in contrast with most model predictions the average degree increases in time, and the node separation decreases. Second, we propose a simple model that captures the network's time evolution. Third, numerical simulations are used to uncover the behavior of quantities that could not be predicted analytically.

Evolution and convergence of the patterns of international scientific collaboration.

PubMed

Coccia, Mario; Wang, Lili

2016-02-23

International research collaboration plays an important role in the social construction and evolution of science. Studies of science increasingly analyze international collaboration across multiple organizations for its impetus in improving research quality, advancing efficiency of the scientific production, and fostering breakthroughs in a shorter time. However, long-run patterns of international research collaboration across scientific fields and their structural changes over time are hardly known. Here we show the convergence of international scientific collaboration across research fields over time. Our study uses a dataset by the National Science Foundation and computes the fraction of papers that have international institutional coauthorships for various fields of science. We compare our results with pioneering studies carried out in the 1970s and 1990s by applying a standardization method that transforms all fractions of internationally coauthored papers into a comparable framework. We find, over 1973-2012, that the evolution of collaboration patterns across scientific disciplines seems to generate a convergence between applied and basic sciences. We also show that the general architecture of international scientific collaboration, based on the ranking of fractions of international coauthorships for different scientific fields per year, has tended to be unchanged over time, at least until now. Overall, this study shows, to our knowledge for the first time, the evolution of the patterns of international scientific collaboration starting from initial results described by literature in the 1970s and 1990s. We find a convergence of these long-run collaboration patterns between the applied and basic sciences. This convergence might be one of contributing factors that supports the evolution of modern scientific fields.

What we learn from eclipsing binaries in the ultraviolet

NASA Technical Reports Server (NTRS)

Guinan, Edward F.

1990-01-01

Recent results on stars and stellar physics from IUE (International Ultraviolet Explorer) observations of eclipsing binaries are discussed. Several case studies are presented, including V 444 Cyg, Aur stars, V 471 Tau and AR Lac. Topics include stellar winds and mass loss, stellar atmospheres, stellar dynamos, and surface activity. Studies of binary star dynamics and evolution are discussed. The progress made with IUE in understanding the complex dynamical and evolutionary processes taking place in W UMa-type binaries and Algol systems is highlighted. The initial results of intensive studies of the W UMa star VW Cep and three representative Algol-type binaries (in different stages of evolution) focused on gas flows and accretion, are included. The future prospects of eclipsing binary research are explored. Remaining problems are surveyed and the next challenges are presented. The roles that eclipsing binaries could play in studies of stellar evolution, cluster dynamics, galactic structure, mass luminosity relations for extra galactic systems, cosmology, and even possible detection of extra solar system planets using eclipsing binaries are discussed.

Displays in space.

PubMed

Colford, Nicholas

2002-04-01

This chapter describes the human and environmental factors that dictate the way that displays must be designed for, and used in space. A brief history of the evolution of such display systems covers developments from the Mercury rockets to the International Space Station. c2002 Published by Elsevier Science B.V.

A history of the autonomic nervous system: part I: from Galen to Bichat.

PubMed

Oakes, Peter C; Fisahn, Christian; Iwanaga, Joe; DiLorenzo, Daniel; Oskouian, Rod J; Tubbs, R Shane

2016-12-01

The development of our current understanding of the autonomic nervous system has a rich history with many international contributors. Although our thoughts of an autonomic nervous system arose with the Greeks, the evolution and final understanding of this neural network would not be fully realized until centuries later. Therefore, our current knowledge of this system is based on hundreds of years of hypotheses and testing and was contributed to by many historic figures.

CLECOS_P: clinical evolution control system on Parkinsonian patients undergoing neural transplantation.

PubMed

Morales, F; Molina, H; Cruz, N; Valladares, P; Muñoz, J; Ortega, I; Torres, O; Leon, M

1995-01-01

The CLECOS_P system was conceived for registering and automating the processing of clinical evaluations performed on patients with Parkinson's disease who undergo functional neurosurgery and/or neural transplant. CLECOS_P represents the first time a computerized system is able to offer--with high precision and considerable time-savings--an integral analysis of the evolutive behavior of the universe in integrated variables at the core assessment program for intracerebral transplantations (CAPIT). CAPIT is used internationally for the evaluation and follow-up of patients with this pathology who have undergone neural transplant. We used the so-called MEDSAC methodology for the preparation of this system. The methodology that was used for the design of an intelligent system aimed at medical decision-making was based on the quantitative analysis of the clinical evolution. At the present moment, there are 20 patients controlled by this system: 11 bilaterally transplanted, 9 unilaterally (registered in ranks of 3 months before operation up to 1, 2, 3, 6, 9, 12, 18, and 24 months after operation). The application of CLECOS_P to these patients permitted the evaluation of 400 clinical variables, where a better evolutive characterization of the patients was obtained, thus getting most favorable results with personalized therapeutic methods aimed at raising their quality of life. CLECOS_P is used in a multi-user environment on a local area network running Novell Netware version 3.11.

COVERING THE SEAMS IN U.S. NATIONAL SECURITY BY APPLYING NETWORK AND TEAM ATTRIBUTES

DTIC Science & Technology

2017-04-06

Today, one such weakness is the seams that exist in the system . Organizational criteria like geography , functions, and responsibilities often create...establishment by the National Security Act of 1947, the modern U.S. national security system has evolved as a result of legislation, presidential preference...and because of changes in the U.S. and international security environments. With each evolution, the system has found ways to function in dealing

Generation and Evolution of Internal Waves in Luzon Strait

DTIC Science & Technology

2015-09-30

1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Generation and Evolution of Internal Waves in Luzon...inertial waves , nonlinear internal waves (NLIWs), and turbulence mixing––in the ocean and thereby help develop improved parameterizations of mixing for...ocean models. Mixing within the stratified ocean is a particular focus as the complex interplay of internal waves from a variety of sources and

Graphical Language Games: Interactional Constraints on Representational Form

ERIC Educational Resources Information Center

Healey, Patrick G. T.; Swoboda, Nik; Umata, Ichiro; King, James

2007-01-01

The emergence of shared symbol systems is considered to be a pivotal moment in human evolution and human development. These changes are normally explained by reference to changes in people's internal cognitive processes. We present 2 experiments which provide evidence that changes in the external, collaborative processes that people use to…

Variational mixed quantum/semiclassical simulation of dihalogen guest and rare-gas solid host dynamics

NASA Astrophysics Data System (ADS)

Cheng, Xiaolu; Cina, Jeffrey A.

2014-07-01

A variational mixed quantum-semiclassical theory for the internal nuclear dynamics of a small molecule and the induced small-amplitude coherent motion of a low-temperature host medium is developed, tested, and used to simulate the temporal evolution of nonstationary states of the internal molecular and surrounding medium degrees of freedom. In this theory, termed the Fixed Vibrational Basis/Gaussian Bath (FVB/GB) method, the system is treated fully quantum mechanically while Gaussian wave packets are used for the bath degrees of freedom. An approximate time-dependent wave function of the entire model is obtained instead of just a reduced system density matrix, so the theory enables the analysis of the entangled system and bath dynamics that ensues following initial displacement of the internal-molecular (system) coordinate from its equilibrium position. The norm- and energy-conserving properties of the propagation of our trial wave function are natural consequences of the Dirac-Frenkel-McLachlan variational principle. The variational approach also stabilizes the time evolution in comparison to the same ansatz propagated under a previously employed locally quadratic approximation to the bath potential and system-bath interaction terms in the bath-parameter equations of motion. Dynamics calculations are carried out for molecular iodine in a 2D krypton lattice that reveal both the time-course of vibrational decoherence and the details of host-atom motion accompanying energy dissipation and dephasing. This work sets the stage for the comprehensive simulation of ultrafast time-resolved optical experiments on small molecules in low-temperature solids.

Evolution of Monitoring and Evaluation of AIDS Response in Ukraine: Laying the Groundwork for Evidence-Based Health Care.

PubMed

Dumchev, Kostyantyn; Varetska, Olga; Kuzin, Ihor

2017-07-01

Once facing the most severe HIV epidemic in Eastern Europe, Ukraine has built an elaborate Monitoring and Evaluation (M&E) system to track the response to AIDS. This system was developed using recommendations and input from multiple international expert organizations and donors and, at the current stage, serves as a best practice model in many areas. The present paper aims to provide a comprehensive overview of the evolution of the M&E system in Ukraine since its inception. Notable achievements and challenges are described and illustrated by epidemiological data and the recommendations for future development are discussed. Unique experiences and advances in M&E in Ukraine may be useful to other countries facing similar epidemiological, structural or methodological issues.

Evolution of the IBDM Structural Latch Development into a Generic Simplified Design

NASA Technical Reports Server (NTRS)

DeVriendt, K.; Dittmer, H.; Vrancken, D.; Urmston, P.; Gracia, O.

2010-01-01

This paper presents the evolution in the development of the structural latch for the International Berthing Docking Mechanism (IBDM, see Figure 1). It reports on the lessons learned since completion of the test program on the engineering development unit of the first generation latching system in 2007. The initial latch design has been through a second generation concept in 2008, and now evolved into a third generation of this mechanism. Functional and structural testing on the latest latch hardware has recently been completed with good results. The IBDM latching system will provide the structural connection between two mated space vehicles after berthing or docking. The mechanism guarantees that the interface seals become compressed to form a leak-tight pressure system that creates a passageway for the astronauts.

The Local Structure of Globalization. The Network Dynamics of Foreign Direct Investments in the International Electricity Industry

NASA Astrophysics Data System (ADS)

Koskinen, Johan; Lomi, Alessandro

2013-05-01

We study the evolution of the network of foreign direct investment (FDI) in the international electricity industry during the period 1994-2003. We assume that the ties in the network of investment relations between countries are created and deleted in continuous time, according to a conditional Gibbs distribution. This assumption allows us to take simultaneously into account the aggregate predictions of the well-established gravity model of international trade as well as local dependencies between network ties connecting the countries in our sample. According to the modified version of the gravity model that we specify, the probability of observing an investment tie between two countries depends on the mass of the economies involved, their physical distance, and the tendency of the network to self-organize into local configurations of network ties. While the limiting distribution of the data generating process is an exponential random graph model, we do not assume the system to be in equilibrium. We find evidence of the effects of the standard gravity model of international trade on evolution of the global FDI network. However, we also provide evidence of significant dyadic and extra-dyadic dependencies between investment ties that are typically ignored in available research. We show that local dependencies between national electricity industries are sufficient for explaining global properties of the network of foreign direct investments. We also show, however, that network dependencies vary significantly over time giving rise to a time-heterogeneous localized process of network evolution.

Long term fault system reorganization of convergent and strike-slip systems

NASA Astrophysics Data System (ADS)

Cooke, M. L.; McBeck, J.; Hatem, A. E.; Toeneboehn, K.; Beyer, J. L.

2017-12-01

Laboratory and numerical experiments representing deformation over many earthquake cycles demonstrate that fault evolution includes episodes of fault reorganization that optimize work on the fault system. Consequently, the mechanical and kinematic efficiencies of fault systems do not increase monotonically through their evolution. New fault configurations can optimize the external work required to accommodate deformation, suggesting that changes in system efficiency can drive fault reorganization. Laboratory evidence and numerical results show that fault reorganization within accretion, strike-slip and oblique convergent systems is associated with increasing efficiency due to increased fault slip (frictional work and seismic energy) and commensurate decreased off-fault deformation (internal work and work against gravity). Between episodes of fault reorganization, fault systems may become less efficient as they produce increasing off fault deformation. For example, laboratory and numerical experiments show that the interference and interaction between different fault segments may increase local internal work or that increasing convergence can increase work against gravity produced by a fault system. This accumulation of work triggers fault reorganization as stored work provides the energy required to grow new faults that reorganize the system to a more efficient configuration. The results of laboratory and numerical experiments reveal that we should expect crustal fault systems to reorganize following periods of increasing inefficiency, even in the absence of changes to the tectonic regime. In other words, fault reorganization doesn't require a change in tectonic loading. The time frame of fault reorganization depends on fault system configuration, strain rate and processes that relax stresses within the crust. For example, stress relaxation may keep pace with stress accumulation, which would limit the increase in the internal work and gravitational work so that irregularities can persist along active fault systems without reorganization of the fault system. Consequently, steady state behavior, for example with constant fault slip rates, may arise either in systems with high degree of stress-relaxation or occur only within the intervals between episodes of fault reorganization.

Giant star seismology

NASA Astrophysics Data System (ADS)

Hekker, S.; Christensen-Dalsgaard, J.

2017-06-01

The internal properties of stars in the red-giant phase undergo significant changes on relatively short timescales. Long near-uninterrupted high-precision photometric timeseries observations from dedicated space missions such as CoRoT and Kepler have provided seismic inferences of the global and internal properties of a large number of evolved stars, including red giants. These inferences are confronted with predictions from theoretical models to improve our understanding of stellar structure and evolution. Our knowledge and understanding of red giants have indeed increased tremendously using these seismic inferences, and we anticipate that more information is still hidden in the data. Unraveling this will further improve our understanding of stellar evolution. This will also have significant impact on our knowledge of the Milky Way Galaxy as well as on exo-planet host stars. The latter is important for our understanding of the formation and structure of planetary systems.

International Conference on Large Meteorite Impacts and Planetary Evolution

NASA Technical Reports Server (NTRS)

1992-01-01

The papers that were accepted for the International Conference on Large Meteorite Impacts and Planetary Evolution, 31 Aug. - 2 Sep. 1992, are presented. One of the major paper topics was the Sudbury project.

Ultrasonic influence on evolution of disordered dislocation structures

NASA Astrophysics Data System (ADS)

Bachurin, D. V.; Murzaev, R. T.; Nazarov, A. A.

2017-12-01

Evolution of disordered dislocation structures under ultrasonic influence is studied in a model two-dimensional grain within the discrete-dislocation approach. Non-equilibrium grain boundary state is mimicked by a mesodefect located at the corners of the grain, stress field of which is described by that of a wedge junction disclination quadrupole. Significant rearrangement related to gliding of lattice dislocations towards the grain boundaries is found, which results in a noticeable reduction of internal stress fields and cancel of disclination quadrupole. The process of dislocation structure evolution passes through two stages: rapid and slow. The main dislocation rearrangement occurs during the first stage. Reduction of internal stress fields is associated with the number of dislocations entered into the grain boundaries. The change of misorientation angle due to lattice dislocations absorbed by the grain boundaries is evaluated. Amplitude of ultrasonic treatment significantly influences the relaxation of dislocation structure. Preliminary elastic relaxation of dislocation structure does not affect substantially the results of the following ultrasonic treatment. Substantial grain size dependence of relaxation of disordered dislocation systems is found. Simulation results are consistent with experimental data.

Cyberhubs: Virtual Research Environments for Astronomy

NASA Astrophysics Data System (ADS)

Herwig, Falk; Andrassy, Robert; Annau, Nic; Clarkson, Ondrea; Côté, Benoit; D’Sa, Aaron; Jones, Sam; Moa, Belaid; O’Connell, Jericho; Porter, David; Ritter, Christian; Woodward, Paul

2018-05-01

Collaborations in astronomy and astrophysics are faced with numerous cyber-infrastructure challenges, such as large data sets, the need to combine heterogeneous data sets, and the challenge to effectively collaborate on those large, heterogeneous data sets with significant processing requirements and complex science software tools. The cyberhubs system is an easy-to-deploy package for small- to medium-sized collaborations based on the Jupyter and Docker technology, which allows web-browser-enabled, remote, interactive analytic access to shared data. It offers an initial step to address these challenges. The features and deployment steps of the system are described, as well as the requirements collection through an account of the different approaches to data structuring, handling, and available analytic tools for the NuGrid and PPMstar collaborations. NuGrid is an international collaboration that creates stellar evolution and explosion physics and nucleosynthesis simulation data. The PPMstar collaboration performs large-scale 3D stellar hydrodynamics simulations of interior convection in the late phases of stellar evolution. Examples of science that is currently performed on cyberhubs, in the areas of 3D stellar hydrodynamic simulations, stellar evolution and nucleosynthesis, and Galactic chemical evolution, are presented.

Proceedings of the International Conference on Integrated Micro/Nanotechnology for Space Applications

NASA Technical Reports Server (NTRS)

1995-01-01

The recent evolution of microelectronic technologies coupled with the growth of micro-electro-mechanical systems (MEMS) has had significant impact in the commercial sector. The focus of this conference was to anticipate and extend the incorporation of nano-electronics and MEMS into application specific integrated microinstruments (ASIM's) in space systems. Presentations ranged from mission application of nano-satellites to silicon micromachining for photonic applications.

Water vascular system architecture in an Ordovician ophiuroid.

PubMed

Clark, Elizabeth G; Bhullar, Bhart-Anjan S; Darroch, Simon A F; Briggs, Derek E G

2017-12-01

Understanding the water vascular system (WVS) in early fossil echinoderms is critical to elucidating the evolution of this system in extant forms. Here we present the first report of the internal morphology of the water vascular system of a stem ophiuroid. The radial canals are internal to the arm, but protected dorsally by a plate separate to the ambulacrals. The canals zig-zag with no evidence of constrictions, corresponding to sphincters, which control pairs of tube feet in extant ophiuroids. The morphology suggests that the unpaired tube feet must have operated individually, and relied on the elasticity of the radial canals, lateral valves and tube foot musculature alone for extension and retraction. This arrangement differs radically from that in extant ophiuroids, revealing a previously unknown Palaeozoic configuration. © 2017 The Author(s).

On the Evolution of Terrestrial Planets: Implications of Evolutionary Paths and Evolving Lid-States

NASA Astrophysics Data System (ADS)

Weller, M. B.; Lenardic, A.

2015-12-01

Growing geodynamic and geochemical evidence suggests that plate tectonics may not have operated on the early Earth, with both the timing of its onset and the length of its activity far from certain [e.g., 1, 2, and references therein]. Accordingly, information from current observations and processes have the potential of sampling portions of the Earth that has both formed under and been modified by differing tectonic regimes. Here we use coupled 3D mantle convection and planetary tectonics simulations to explore evolutionary paths and planetary tectonic regimes. Early in the geologic lifetime of a terrestrial planet, high mantle temperatures favour stagnant-lids. As radiogenics decay, an initial stagnant-lid may yield into a high temperature mobile-lid state. The transition from an initial stagnant-lid is a function of yield strength, in addition to both internal and surface temperatures. Each lid-state has specific diagnostics and implications for internal parameters, and consequently planetary evolution. The implication within this framework is that a system with a different thermal evolution has the potential to migrate through tectonic regimes at the same 'thermal time' (e.g. temperature), but very different 'temporal times'. This indicate that multiple modes of convection and surface tectonics can potentially operate on a single planetary body at different times in its evolution, as consequence of changing internal parameters, surface temperatures, and differing thermal histories. We will discuss the implications of terrestrial worlds that can alternate, and be offset between multiple tectonic states over giga-year timescales. [1] O'Neill et. al. (2013b) Geol. Soc. London; [2] Weller et al. (2015) EPSL

Literacy Instruction in Mexico. International Studies in Education.

ERIC Educational Resources Information Center

Miller, Robert

Beginning in 1978, a 20-year study charted the evolution of the public education system in Mexico, focusing on literacy instruction for various age groups and special populations. Drawing on descriptions of schools visited during the author's 13 visits to Mexico, this book describes Mexican educational practices, with the aim of helping U.S.…

The Fourth World Conservation Lecture: The Evolution of Conservation and Contemporary Issues.

ERIC Educational Resources Information Center

Kassas, Mohammed

1985-01-01

Traces the international movements that focused on the conservation and protection of nature within the past five decades. Explains how man-nature relationships are influenced by the interaction of the three systems of the biosphere, technosphere, and sociosphere. Issues involved with deforestation and desertification are also described. (ML)

Cryovolcanism on Ceres

NASA Astrophysics Data System (ADS)

Ruesch, O.; Platz, T.; Schenk, P.; McFadden, L. A.; Castillo-Rogez, J. C.; Quick, L. C.; Byrne, S.; Preusker, F.; O'Brien, D. P.; Schmedemann, N.; Williams, D. A.; Li, J.-Y.; Bland, M. T.; Hiesinger, H.; Kneissl, T.; Neesemann, A.; Schaefer, M.; Pasckert, J. H.; Schmidt, B. E.; Buczkowski, D. L.; Sykes, M. V.; Nathues, A.; Roatsch, T.; Hoffmann, M.; Raymond, C. A.; Russell, C. T.

2016-09-01

Volcanic edifices are abundant on rocky bodies of the inner solar system. In the cold outer solar system, volcanism can occur on solid bodies with a water-ice shell, but derived cryovolcanic constructs have proved elusive. We report the discovery, using Dawn Framing Camera images, of a landform on dwarf planet Ceres that we argue represents a viscous cryovolcanic dome. Parent material of the cryomagma is a mixture of secondary minerals, including salts and water ice. Absolute model ages from impact craters reveal that extrusion of the dome has occurred recently. Ceres’ evolution must have been able to sustain recent interior activity and associated surface expressions. We propose salts with low eutectic temperatures and thermal conductivities as key drivers for Ceres’ long-term internal evolution.

Cryovolcanism on Ceres

USGS Publications Warehouse

Ruesch, O.; Platz, T.; Schenk, P.; McFadden, L.A.; Castillo-Rogez, J. C.; Quick, L. C.; Byrne, S.; Preusker, F.; O'Brien, D. P.; Schmedemann, N.; Williams, D.A.; Li, Jian-Yang; Bland, M. T.; Hiesinger, H.; Kneissl, T.; Neesemann, A.; Schaefer, M.; Pasckert, J. H.; Schmidt, B.E.; Buczkowski, D.L.; Sykes, M. V.; Nathues, A.; Roatsch, T.; Hoffman, M.; Raymond, C.A.; Russell, C.T.

2016-01-01

Volcanic edifices are abundant on rocky bodies of the inner solar system. In the cold outer solar system, volcanism can occur on solid bodies with a water-ice shell, but derived cryovolcanic constructs have proved elusive. We report the discovery using Dawn Framing Camera images of a landform on dwarf planet Ceres, which we argue represents a viscous cryovolcanic dome. Parent material of the cryomagma is a mixture of secondary minerals, including salts and water ice. Absolute model ages from impact craters reveal that extrusion of the dome has occurred recently. Ceres’ evolution must have been able to sustain recent interior activity and associated surface expressions. We propose salts with low eutectic temperatures and thermal conductivities as key drivers for Ceres’ long-term internal evolution.

MEDLARS and the Library Community

PubMed Central

Adams, Scott

1964-01-01

The intention of the National Library of Medicine is to share with other libraries the products and the capabilities developed by the MEDLARS system. MEDLARS will provide bibliographic services of use to other libraries from the central system. The decentralization of the central system to permit libraries with access to computers to establish local machine retrieval systems is also indicated. The implications of such decentralization for the American medical library network and its effect on library evolution are suggested, as are the implications for international development of mechanized storage and retrieval systems. PMID:14119289

A systems approach defining constraints of the genome architecture on lineage selection and evolvability during somatic cancer evolution

PubMed Central

Rübben, Albert; Nordhoff, Ole

2013-01-01

Summary Most clinically distinguishable malignant tumors are characterized by specific mutations, specific patterns of chromosomal rearrangements and a predominant mechanism of genetic instability but it remains unsolved whether modifications of cancer genomes can be explained solely by mutations and selection through the cancer microenvironment. It has been suggested that internal dynamics of genomic modifications as opposed to the external evolutionary forces have a significant and complex impact on Darwinian species evolution. A similar situation can be expected for somatic cancer evolution as molecular key mechanisms encountered in species evolution also constitute prevalent mutation mechanisms in human cancers. This assumption is developed into a systems approach of carcinogenesis which focuses on possible inner constraints of the genome architecture on lineage selection during somatic cancer evolution. The proposed systems approach can be considered an analogy to the concept of evolvability in species evolution. The principal hypothesis is that permissive or restrictive effects of the genome architecture on lineage selection during somatic cancer evolution exist and have a measurable impact. The systems approach postulates three classes of lineage selection effects of the genome architecture on somatic cancer evolution: i) effects mediated by changes of fitness of cells of cancer lineage, ii) effects mediated by changes of mutation probabilities and iii) effects mediated by changes of gene designation and physical and functional genome redundancy. Physical genome redundancy is the copy number of identical genetic sequences. Functional genome redundancy of a gene or a regulatory element is defined as the number of different genetic elements, regardless of copy number, coding for the same specific biological function within a cancer cell. Complex interactions of the genome architecture on lineage selection may be expected when modifications of the genome architecture have multiple and possibly opposed effects which manifest themselves at disparate times and progression stages. Dissection of putative mechanisms mediating constraints exerted by the genome architecture on somatic cancer evolution may provide an algorithm for understanding and predicting as well as modifying somatic cancer evolution in individual patients. PMID:23336076

Making short-term climate forecasts useful: Linking science and action

PubMed Central

Buizer, James; Jacobs, Katharine; Cash, David

2016-01-01

This paper discusses the evolution of scientific and social understanding that has led to the development of knowledge systems supporting the application of El Niño-Southern Oscillation (ENSO) forecasts, including the development of successful efforts to connect climate predictions with sectoral applications and actions “on the ground”. The evolution of “boundary-spanning” activities to connect science and decisionmaking is then discussed, setting the stage for a report of outcomes from an international workshop comprised of producers, translators, and users of climate predictions. The workshop, which focused on identifying critical boundary-spanning features of successful boundary organizations, included participants from Australia, Hawaii, and the Pacific Islands, the US Pacific Northwest, and the state of Ceará in northwestern Brazil. Workshop participants agreed that boundary organizations have multiple roles including those of information broker, convenor of forums for engagement, translator of scientific information, arbiter of access to knowledge, and exemplar of adaptive behavior. Through these roles, boundary organizations will ensure the stability of the knowledge system in a changing political, economic, and climatic context. The international examples reviewed in this workshop demonstrated an interesting case of convergent evolution, where organizations that were very different in origin evolved toward similar structures and individuals engaged in them had similar experiences to share. These examples provide evidence that boundary organizations and boundary-spanners fill some social/institutional roles that are independent of culture. PMID:20133668

Making short-term climate forecasts useful: Linking science and action.

PubMed

Buizer, James; Jacobs, Katharine; Cash, David

2016-04-26

This paper discusses the evolution of scientific and social understanding that has led to the development of knowledge systems supporting the application of El Niño-Southern Oscillation (ENSO) forecasts, including the development of successful efforts to connect climate predictions with sectoral applications and actions "on the ground". The evolution of "boundary-spanning" activities to connect science and decisionmaking is then discussed, setting the stage for a report of outcomes from an international workshop comprised of producers, translators, and users of climate predictions. The workshop, which focused on identifying critical boundary-spanning features of successful boundary organizations, included participants from Australia, Hawaii, and the Pacific Islands, the US Pacific Northwest, and the state of Ceará in northwestern Brazil. Workshop participants agreed that boundary organizations have multiple roles including those of information broker, convenor of forums for engagement, translator of scientific information, arbiter of access to knowledge, and exemplar of adaptive behavior. Through these roles, boundary organizations will ensure the stability of the knowledge system in a changing political, economic, and climatic context. The international examples reviewed in this workshop demonstrated an interesting case of convergent evolution, where organizations that were very different in origin evolved toward similar structures and individuals engaged in them had similar experiences to share. These examples provide evidence that boundary organizations and boundary-spanners fill some social/institutional roles that are independent of culture.

Evolution of regulatory networks towards adaptability and stability in a changing environment

NASA Astrophysics Data System (ADS)

Lee, Deok-Sun

2014-11-01

Diverse biological networks exhibit universal features distinguished from those of random networks, calling much attention to their origins and implications. Here we propose a minimal evolution model of Boolean regulatory networks, which evolve by selectively rewiring links towards enhancing adaptability to a changing environment and stability against dynamical perturbations. We find that sparse and heterogeneous connectivity patterns emerge, which show qualitative agreement with real transcriptional regulatory networks and metabolic networks. The characteristic scaling behavior of stability reflects the balance between robustness and flexibility. The scaling of fluctuation in the perturbation spread shows a dynamic crossover, which is analyzed by investigating separately the stochasticity of internal dynamics and the network structure differences depending on the evolution pathways. Our study delineates how the ambivalent pressure of evolution shapes biological networks, which can be helpful for studying general complex systems interacting with environments.

Chemical roots of biological evolution: the origins of life as a process of development of autonomous functional systems

PubMed Central

Ruiz-Mirazo, Kepa; Briones, Carlos

2017-01-01

In recent years, an extension of the Darwinian framework is being considered for the study of prebiotic chemical evolution, shifting the attention from homogeneous populations of naked molecular species to populations of heterogeneous, compartmentalized and functionally integrated assemblies of molecules. Several implications of this shift of perspective are analysed in this critical review, both in terms of the individual units, which require an adequate characterization as self-maintaining systems with an internal organization, and also in relation to their collective and long-term evolutionary dynamics, based on competition, collaboration and selection processes among those complex individuals. On these lines, a concrete proposal for the set of molecular control mechanisms that must be coupled to bring about autonomous functional systems, at the interface between chemistry and biology, is provided. PMID:28446711

Chemical roots of biological evolution: the origins of life as a process of development of autonomous functional systems.

PubMed

Ruiz-Mirazo, Kepa; Briones, Carlos; de la Escosura, Andrés

2017-04-01

In recent years, an extension of the Darwinian framework is being considered for the study of prebiotic chemical evolution, shifting the attention from homogeneous populations of naked molecular species to populations of heterogeneous, compartmentalized and functionally integrated assemblies of molecules. Several implications of this shift of perspective are analysed in this critical review, both in terms of the individual units, which require an adequate characterization as self-maintaining systems with an internal organization, and also in relation to their collective and long-term evolutionary dynamics, based on competition, collaboration and selection processes among those complex individuals. On these lines, a concrete proposal for the set of molecular control mechanisms that must be coupled to bring about autonomous functional systems, at the interface between chemistry and biology, is provided. © 2017 The Authors.

The Evolution of Al Qaeda

DTIC Science & Technology

2007-06-15

Al Qaeda is a product of the forces of globalization. Increasing access to global finances , international travel, and sophisticated technology is...evolution. Al Qaeda is a product of the forces of globalization. Increasing access to global finances , international travel, and sophisticated technology...75 Finance

Evolution of the social network of scientific collaborations

NASA Astrophysics Data System (ADS)

Barabási, A. L.; Jeong, H.; Néda, Z.; Ravasz, E.; Schubert, A.; Vicsek, T.

2002-08-01

The co-authorship network of scientists represents a prototype of complex evolving networks. In addition, it offers one of the most extensive database to date on social networks. By mapping the electronic database containing all relevant journals in mathematics and neuro-science for an 8-year period (1991-98), we infer the dynamic and the structural mechanisms that govern the evolution and topology of this complex system. Three complementary approaches allow us to obtain a detailed characterization. First, empirical measurements allow us to uncover the topological measures that characterize the network at a given moment, as well as the time evolution of these quantities. The results indicate that the network is scale-free, and that the network evolution is governed by preferential attachment, affecting both internal and external links. However, in contrast with most model predictions the average degree increases in time, and the node separation decreases. Second, we propose a simple model that captures the network's time evolution. In some limits the model can be solved analytically, predicting a two-regime scaling in agreement with the measurements. Third, numerical simulations are used to uncover the behavior of quantities that could not be predicted analytically. The combined numerical and analytical results underline the important role internal links play in determining the observed scaling behavior and network topology. The results and methodologies developed in the context of the co-authorship network could be useful for a systematic study of other complex evolving networks as well, such as the world wide web, Internet, or other social networks.

Evolution of Secondary Software Businesses: Understanding Industry Dynamics

NASA Astrophysics Data System (ADS)

Tyrväinen, Pasi; Warsta, Juhani; Seppänen, Veikko

Primary software industry originates from IBM's decision to unbundle software-related computer system development activities to external partners. This kind of outsourcing from an enterprise internal software development activity is a common means to start a new software business serving a vertical software market. It combines knowledge of the vertical market process with competence in software development. In this research, we present and analyze the key figures of the Finnish secondary software industry, in order to quantify its interaction with the primary software industry during the period of 2000-2003. On the basis of the empirical data, we present a model for evolution of a secondary software business, which makes explicit the industry dynamics. It represents the shift from internal software developed for competitive advantage to development of products supporting standard business processes on top of standardized technologies. We also discuss the implications for software business strategies in each phase.

Professional Development in the International Year of Astronomy: Expanding the Universe in the Classroom

NASA Astrophysics Data System (ADS)

Reinfeld, Erika L.; Harman, P.; Lee, M. H.; Bailey, J. M.

2008-05-01

The International Year of Astronomy offers unparalleled opportunity to expand our audiences’ understanding about the universe. However, many learners, students and adults alike, are unfamiliar with the universe beyond the solar system. This collaborative workshop explores strategies for teacher professional development around the origin and evolution of the universe, using the resources of the Beyond the Solar System Professional Development Project as a guide. The Beyond the Solar System (BtSS) Professional Development Project is a NASA-supported initiative from the Harvard-Smithsonian Center for Astrophysics (CfA) designed to foster public understanding of NASA's exciting astronomy and space science research. The BtSS portfolio includes video resources, assessment tools, data about common student ideas, content presentations, online telescope investigations, and other classroom activities designed to deepen content knowledge and improve the quality of teaching and learning about current scientific models and evidence for the origin and evolution of our universe of galaxies. During this session, members of the BtSS Leadership Team from around the country will share their experience using these resources in educator workshops and teacher-training courses, and facilitate discussions among workshop participants about how these materials and pedagogical strategies can be used in their own professional development efforts during the International Year of Astronomy. EPO specialists and scientists will engage in focused exploration of the project's DVD--"Expanding the Universe in the Classroom"--in order make explicit connections between the themes of the International Year of Astronomy and their own work. The goals of this workshop are to equip professional development providers to support IYA education efforts in classrooms, afterschool programs, and informal education venues and to raise awareness about the opportunities for continuing Galileo's legacy of discovery through current science and online telescopes.

Firewall systems: the next generation

NASA Astrophysics Data System (ADS)

McGhie, Lynda L.

1996-01-01

To be competitive in today's globally connected marketplace, a company must ensure that their internal network security methodologies and supporting policies are current and reflect an overall understanding of today's technology and its resultant threats. Further, an integrated approach to information security should ensure that new ways of sharing information and doing business are accommodated; such as electronic commerce, high speed public broadband network services, and the federally sponsored National Information Infrastructure. There are many challenges, and success is determined by the establishment of a solid and firm baseline security architecture that accommodate today's external connectivity requirements, provides transitional solutions that integrate with evolving and dynamic technologies, and ultimately acknowledges both the strategic and tactical goals of an evolving network security architecture and firewall system. This paper explores the evolution of external network connectivity requirements, the associated challenges and the subsequent development and evolution of firewall security systems. It makes the assumption that a firewall is a set of integrated and interoperable components, coming together to form a `SYSTEM' and must be designed, implement and managed as such. A progressive firewall model will be utilized to illustrates the evolution of firewall systems from earlier models utilizing separate physical networks, to today's multi-component firewall systems enabling secure heterogeneous and multi-protocol interfaces.

Continuous measurement of an atomic current

NASA Astrophysics Data System (ADS)

Laflamme, C.; Yang, D.; Zoller, P.

2017-04-01

We are interested in dynamics of quantum many-body systems under continuous observation, and its physical realizations involving cold atoms in lattices. In the present work we focus on continuous measurement of atomic currents in lattice models, including the Hubbard model. We describe a Cavity QED setup, where measurement of a homodyne current provides a faithful representation of the atomic current as a function of time. We employ the quantum optical description in terms of a diffusive stochastic Schrödinger equation to follow the time evolution of the atomic system conditional to observing a given homodyne current trajectory, thus accounting for the competition between the Hamiltonian evolution and measurement back action. As an illustration, we discuss minimal models of atomic dynamics and continuous current measurement on rings with synthetic gauge fields, involving both real space and synthetic dimension lattices (represented by internal atomic states). Finally, by "not reading" the current measurements the time evolution of the atomic system is governed by a master equation, where—depending on the microscopic details of our CQED setups—we effectively engineer a current coupling of our system to a quantum reservoir. This provides interesting scenarios of dissipative dynamics generating "dark" pure quantum many-body states.

A Proposed Neurological Interpretation of Language Evolution.

PubMed

Ardila, Alfredo

2015-01-01

Since the very beginning of the aphasia history it has been well established that there are two major aphasic syndromes (Wernicke's-type and Broca's-type aphasia); each one of them is related to the disturbance at a specific linguistic level (lexical/semantic and grammatical) and associated with a particular brain damage localization (temporal and frontal-subcortical). It is proposed that three stages in language evolution could be distinguished: (a) primitive communication systems similar to those observed in other animals, including nonhuman primates; (b) initial communication systems using sound combinations (lexicon) but without relationships among the elements (grammar); and (c) advanced communication systems including word-combinations (grammar). It is proposed that grammar probably originated from the internal representation of actions, resulting in the creation of verbs; this is an ability that depends on the so-called Broca's area and related brain networks. It is suggested that grammar is the basic ability for the development of so-called metacognitive executive functions. It is concluded that while the lexical/semantic language system (vocabulary) probably appeared during human evolution long before the contemporary man (Homo sapiens sapiens), the grammatical language historically represents a recent acquisition and is correlated with the development of complex cognition (metacognitive executive functions).

A Proposed Neurological Interpretation of Language Evolution

PubMed Central

2015-01-01

Since the very beginning of the aphasia history it has been well established that there are two major aphasic syndromes (Wernicke's-type and Broca's-type aphasia); each one of them is related to the disturbance at a specific linguistic level (lexical/semantic and grammatical) and associated with a particular brain damage localization (temporal and frontal-subcortical). It is proposed that three stages in language evolution could be distinguished: (a) primitive communication systems similar to those observed in other animals, including nonhuman primates; (b) initial communication systems using sound combinations (lexicon) but without relationships among the elements (grammar); and (c) advanced communication systems including word-combinations (grammar). It is proposed that grammar probably originated from the internal representation of actions, resulting in the creation of verbs; this is an ability that depends on the so-called Broca's area and related brain networks. It is suggested that grammar is the basic ability for the development of so-called metacognitive executive functions. It is concluded that while the lexical/semantic language system (vocabulary) probably appeared during human evolution long before the contemporary man (Homo sapiens sapiens), the grammatical language historically represents a recent acquisition and is correlated with the development of complex cognition (metacognitive executive functions). PMID:26124540

Update on the genomics and basic biology of Brachypodium: International Brachypodium Initiative (IBI).

PubMed

Catalan, Pilar; Chalhoub, Boulos; Chochois, Vincent; Garvin, David F; Hasterok, Robert; Manzaneda, Antonio J; Mur, Luis A J; Pecchioni, Nicola; Rasmussen, Søren K; Vogel, John P; Voxeur, Aline

2014-07-01

The scientific presentations at the First International Brachypodium Conference (abstracts available at http://www.brachy2013.unimore.it) are evidence of the widespread adoption of Brachypodium distachyon as a model system. Furthermore, the wide range of topics presented (genome evolution, roots, abiotic and biotic stress, comparative genomics, natural diversity, and cell walls) demonstrates that the Brachypodium research community has achieved a critical mass of tools and has transitioned from resource development to addressing biological questions, particularly those unique to grasses. Copyright © 2014 Elsevier Ltd. All rights reserved.

International symposium on erosion and landscape evolution abstracts

USDA-ARS?s Scientific Manuscript database

This book contains all of the extended abstracts from the ASABE specialty conference, the International Symposium on Erosion and Landscape Evolution (ISELE), held September 18-21, 2011 at the Hilton Anchorage Hotel in Anchorage, Alaska. Three extended abstracts from the meeting keynote speakers as ...

Two-dimensional evolution equation of finite-amplitude internal gravity waves in a uniformly stratified fluid

PubMed

Kataoka; Tsutahara; Akuzawa

2000-02-14

We derive a fully nonlinear evolution equation that can describe the two-dimensional motion of finite-amplitude long internal waves in a uniformly stratified three-dimensional fluid of finite depth. The derived equation is the two-dimensional counterpart of the evolution equation obtained by Grimshaw and Yi [J. Fluid Mech. 229, 603 (1991)]. In the small-amplitude limit, our equation is reduced to the celebrated Kadomtsev-Petviashvili equation.

SIRE: A Simple Interactive Rule Editor for NICBES

NASA Technical Reports Server (NTRS)

Bykat, Alex

1988-01-01

To support evolution of domain expertise, and its representation in an expert system knowledge base, a user-friendly rule base editor is mandatory. The Nickel Cadmium Battery Expert System (NICBES), a prototype of an expert system for the Hubble Space Telescope power storage management system, does not provide such an editor. In the following, a description of a Simple Interactive Rule Base Editor (SIRE) for NICBES is described. The SIRE provides a consistent internal representation of the NICBES knowledge base. It supports knowledge presentation and provides a user-friendly and code language independent medium for rule addition and modification. The SIRE is integrated with NICBES via an interface module. This module provides translation of the internal representation to Prolog-type rules (Horn clauses), latter rule assertion, and a simple mechanism for rule selection for its Prolog inference engine.

Dollar’s Vulnerability and the Implications for National Security

DTIC Science & Technology

2009-12-01

higher inflation leads to exchange - rate depreciation as well as increased volatility. 36 This indicates that expansionary monetary policy would also...resulted in debasement and depreciation.7 Thus, exchange rate and currency convertibility problems...creation and evolution of international currencies. The problems of establishing and maintaining exchange rates and retaining value led to a system

International Trends in the Implementation of Assessment for Learning: Implications for Policy and Practice

ERIC Educational Resources Information Center

Birenbaum, Menucha; DeLuca, Christopher; Earl, Lorna; Heritage, Margaret; Klenowski, Val; Looney, Anne; Smith, Kari; Timperley, Helen; Volante, Louis; Wyatt-Smith, Claire

2015-01-01

This paper discusses the emergence of assessment for learning (AfL) across the globe with particular attention given to Western educational jurisdictions. Authors from Australia, Canada, Ireland, Israel, New Zealand, Norway, and the USA explain the genesis of AfL, its evolution and impact on school systems, and discuss current trends in policy…

The Russian Market of University Services: Social and Demographic Aspects

ERIC Educational Resources Information Center

Bydanova, Elizaveta; Mushketova, Natalia; Rouet, Gilles

2015-01-01

Purpose: The purpose of this paper is to analyze the impact of demographic, social, economic and international aspects on the market of university services in Russia. It also reminds readers briefly of the evolution of the Russian higher education system during the last 20 years and considers some consequences of the current public policy and…

Doctoral and Postdoctoral Education in Science and Engineering: Europe in the International Competition

ERIC Educational Resources Information Center

MOGUEROU, PHILIPPE

2005-01-01

In this article, we discuss the recent evolutions of science and engineering doctoral and postdoctoral education in Europe. Indeed, Ph.Ds are crucial to the conduct of research and innovation in the national innovation systems, as they provide a large amount of input into creating the competitive advantage, notably through basic research. First,…

Socio-hydrologic perspectives of the co-evolution of humans and water in the Tarim River Basin, Western China: the Taiji-Tire Model

NASA Astrophysics Data System (ADS)

Liu, Y.; Tian, F.; Hu, H.; Sivapalan, M.

2013-10-01

This paper presents a historical socio-hydrological analysis of the Tarim Basin, Xinjiang Province, Western China, from the time of the opening of the Silk Road to the present. The analysis is aimed at exploring the historical co-evolution of coupled human-water systems and at identifying common patterns or organizing principles underpinning socio-hydrological systems (SHS). As a self-organized entity, the evolution of the human-water system in the Tarim Basin reached stable states for long periods of time, then punctuated by sudden shifts due to internal or external disturbances. In this study, we discuss three steady periods (i.e. natural, human exploitation, and degradation and recovery) and transitions in between during the past 2000 yr. During the "natural" stage that existed pre-18th century, with small-scale human society and sound environment, evolution of the SHS was mainly driven by natural environmental changes such as river channel migration and climate change. During the human exploitation stage, especially in the 19th and 20th centuries, it experienced rapid population growth, massive land reclamation and fast socio-economic development, and humans became the principal players of system evolution. By the 1970s, the Tarim Basin had evolved into a new regime with a vulnerable eco-hydrological system seemingly populated beyond its carrying capacity, and a human society that began to suffer from serious water shortages, land salinization and desertification. With intensified deterioration of river health and increased recognition of unsustainability of traditional development pattern, human intervention and recovery measures have been adopted. Since then, the basin has shown a reverse regime shift towards some healing of the environmental damage. Spatio-temporal variations of historical socio-hydrological co-evolution are classified into four types: primitive agricultural, traditional agricultural, industrial agricultural and urban SHSs. These co-evolutionary changes have been summarized in terms of the Taiji-Tire Model, a refinement of a special concept in Chinese philosophy, relating to the co-evolution of a system because of interactions among its components.

The evolution of the Japanese medical education system: a historical perspective.

PubMed

Kuwabara, Norimitsu; Yamashita, Miu; Yee, Keolamau; Kurahara, David

2015-03-01

The Japanese Medical Education system has been influenced by political events throughout the country's history. From long periods of isolation from the western world to the effect of world wars, Japan's training system for physicians has had to adapt in many ways and will continue to change. The Japanese medical education system was recently compared to the "Galapagos Islands" for its unusual and singular evolution, in a speech by visiting professor Dr. Gordon L. Noel at the University of Tokyo International Research center.1 Japanese medical schools are currently working to increase their students' clinical hours or else these students may not be able to train in the United States for residencies. Knowing the history of the Japanese Medical education system is paramount to understanding the current system in place today. Studying the historical foundation of this system will also provide insight on how the system must change in order to produce better clinicians. This article provides a glimpse into the medical system of another nation that may encourage needed reflection on the state of current healthcare training in the United States.

A hypothesis on the biological origins and social evolution of music and dance.

PubMed

Wang, Tianyan

2015-01-01

The origins of music and musical emotions is still an enigma, here I propose a comprehensive hypothesis on the origins and evolution of music, dance, and speech from a biological and sociological perspective. I suggest that every pitch interval between neighboring notes in music represents corresponding movement pattern through interpreting the Doppler effect of sound, which not only provides a possible explanation for the transposition invariance of music, but also integrates music and dance into a common form-rhythmic movements. Accordingly, investigating the origins of music poses the question: why do humans appreciate rhythmic movements? I suggest that human appreciation of rhythmic movements and rhythmic events developed from the natural selection of organisms adapting to the internal and external rhythmic environments. The perception and production of, as well as synchronization with external and internal rhythms are so vital for an organism's survival and reproduction, that animals have a rhythm-related reward and emotion (RRRE) system. The RRRE system enables the appreciation of rhythmic movements and events, and is integral to the origination of music, dance and speech. The first type of rewards and emotions (rhythm-related rewards and emotions, RRREs) are evoked by music and dance, and have biological and social functions, which in turn, promote the evolution of music, dance and speech. These functions also evoke a second type of rewards and emotions, which I name society-related rewards and emotions (SRREs). The neural circuits of RRREs and SRREs develop in species formation and personal growth, with congenital and acquired characteristics, respectively, namely music is the combination of nature and culture. This hypothesis provides probable selection pressures and outlines the evolution of music, dance, and speech. The links between the Doppler effect and the RRREs and SRREs can be empirically tested, making the current hypothesis scientifically concrete.

Knowledge-based vision and simple visual machines.

PubMed Central

Cliff, D; Noble, J

1997-01-01

The vast majority of work in machine vision emphasizes the representation of perceived objects and events: it is these internal representations that incorporate the 'knowledge' in knowledge-based vision or form the 'models' in model-based vision. In this paper, we discuss simple machine vision systems developed by artificial evolution rather than traditional engineering design techniques, and note that the task of identifying internal representations within such systems is made difficult by the lack of an operational definition of representation at the causal mechanistic level. Consequently, we question the nature and indeed the existence of representations posited to be used within natural vision systems (i.e. animals). We conclude that representations argued for on a priori grounds by external observers of a particular vision system may well be illusory, and are at best place-holders for yet-to-be-identified causal mechanistic interactions. That is, applying the knowledge-based vision approach in the understanding of evolved systems (machines or animals) may well lead to theories and models that are internally consistent, computationally plausible, and entirely wrong. PMID:9304684

CoRoT-2b: a Tidally Inflated, Young Exoplanet?

NASA Astrophysics Data System (ADS)

Guillot, Tristan; Havel, M.

2009-09-01

CoRoT-2b is among the most anomalously large transiting exoplanet known. Due to its large mass (3.3 Mjup), its large radius ( 1.5 Rjup) cannot be explained by standard evolution models. Recipes that work for other anomalously large exoplanets (e.g. HD209458b), such as invoking kinetic energy transport in the planetary interior or increased opacities, clearly fail for CoRoT-2b. Interestingly, the planet's parent star is an active star with a large fraction (7 to 20%) of spots and a rapid rotation (4.5 days). We first model the star's evolution to accurately constrain the planetary parameters. We find that the stellar activity has little influence on the star's evolution and inferred parameters. However, stellar evolution models point towards two kind of solutions for the star-planet system: (i) a very young system (20-40 Ma) with a star still undergoing pre-main sequence contraction, and a planet which could have a radius as low as 1.4 Rjup, or (ii) a young main-sequence star (40 to 500 Ma) with a planet that is slightly more inflated ( 1.5 Rjup). In either case, planetary evolution models require a significant added internal energy to explain the inferred planet size: from a minimum of 3x1028 erg/s in case (i), to up to 1.5x1029 erg/s in case (ii). We find that evolution models consistently including planet/star tides are able to reproduce the inferred radius but only for a short period of time ( 10 Ma). This points towards a young age for the star/planet system and dissipation by tides due to either circularization or synchronization of the planet. Additional observations of the star (infrared excess due to disk?) and of the planet (precise Rossiter effect, IR secondary eclispe) would be highly valuable to understand the early evolution of star-exoplanet systems.

Three-dimensional transient numerical simulation for intake process in the engine intake port-valve-cylinder system.

PubMed

Luo, Ma-Ji; Chen, Guo-Hua; Ma, Yuan-Hao

2003-01-01

This paper presents a KIVA-3 code based numerical model for three-dimensional transient intake flow in the intake port-valve-cylinder system of internal combustion engine using body-fitted technique, which can be used in numerical study on internal combustion engine with vertical and inclined valves, and has higher calculation precision. A numerical simulation (on the intake process of a two-valve engine with a semi-sphere combustion chamber and a radial intake port) is provided for analysis of the velocity field and pressure field of different plane at different crank angles. The results revealed the formation of the tumble motion, the evolution of flow field parameters and the variation of tumble ratios as important information for the design of engine intake system.

International Ultraviolet Explorer observations of the peculiar variable spectrum of the eclipsing binary R Arae

NASA Technical Reports Server (NTRS)

Mccluskey, G. E.; Kondo, Y.

1983-01-01

The eclipsing binary system R Arae = HD 149730 is a relatively bright southern system with an orbital period of about 4.4 days. It is a single-lined spectroscopic binary. The spectral class of the primary component is B9 Vp. The system was included in a study of mass flow and evolution in close binary systems using the International Ultraviolet Explorer satellite (IUE). Four spectra in the wavelength range from 1150 to 1900 A were obtained with the far-ultraviolet SWP camera, and six spectra in the range from 1900 to 3200 range were obtained with the mid-ultraviolet LWR camera. The close binary R Arae exhibits very unusual ultraviolet spectra. It appears that no other close binary system, observed with any of the orbiting satellites, shows outside-eclipse ultraviolet continuum flux variations of this nature.

Modelling the evolution of a comet subsurface: implications for 67P/Churyumov-Gerasimenko

NASA Astrophysics Data System (ADS)

Guilbert-Lepoutre, Aurélie; Rosenberg, Eric D.; Prialnik, Dina; Besse, Sébastien

2016-11-01

Modelling the evolution of comets is a complex task aiming at providing constraints on physical processes and internal properties that are inaccessible to observations, although they could potentially bring key elements to our understanding of the origins of these primitive objects. This field has made a tremendous step forward in the post-Giotto area, owing to detailed space- and ground-based observations, as well as detailed laboratory simulations of comet nuclei. In this paper, we review studies that we believe are significant for interpreting the observations of 67P/Churyumov-Gerasimenko by the ESA/Rosetta mission, and provide new calculations where needed. These studies hold a strong statistical significance, which is exactly what is needed for this comet with an orbital evolution that cannot be traced back accurately for more than hundreds of years. We show that radial and lateral differentiation may have occurred on 67P's chaotic path to the inner Solar system, and that internal inhomogeneities may result in an erratic activity pattern. Finally, we discuss the origins of circular depressions seen on several comets including 67P, and suggest that they could be considered as evidence of the past processing of subsurface layers.

Asteroids, Comets, Meteors 2014

NASA Astrophysics Data System (ADS)

Muinonen, K.; Penttilä, A.; Granvik, M.; Virkki, A.; Fedorets, G.; Wilkman, O.; Kohout, T.

2014-08-01

Asteroids, Comets, Meteors focuses on the research of small Solar System bodies. Small bodies are the key to understanding the formation and evolution of the Solar System, carrying signals from pre-solar times. Understanding the evolution of the Solar System helps unveil the evolution of extrasolar planetary systems. Societally, small bodies will be important future resources of minerals. The near-Earth population of small bodies continues to pose an impact hazard, whether it be small pieces of falling meteorites or larger asteroids or cometary nuclei capable of causing global environmental effects. The conference series entitled ''Asteroids, Comets, Meteors'' constitutes the leading international series in the field of small Solar System bodies. The first three conferences took place in Uppsala, Sweden in 1983, 1985, and 1989. The conference is now returning to Nordic countries after a quarter of a century. After the Uppsala conferences, the conference has taken place in Flagstaff, Arizona, U.S.A. in 1991, Belgirate, Italy in 1993, Paris, France in 1996, Ithaca, New York, U.S.A. in 1999, in Berlin, Germany in 2002, in Rio de Janeiro, Brazil in 2005, in Baltimore, Maryland, U.S.A. in 2008, and in Niigata, Japan in 2012. ACM in Helsinki, Finland in 2014 will be the 12th conference in the series.

Heliophysics: Evolving Solar Activity and the Climates of Space and Earth

NASA Astrophysics Data System (ADS)

Schrijver, Carolus J.; Siscoe, George L.

2010-09-01

Preface; 1. Interconnectedness in heliophysics Carolus J. Schrijver and George L. Siscoe; 2. Long-term evolution of magnetic activity of Sun-like stars Carolus J. Schrijver; 3. Formation and early evolution of stars and proto-planetary disks Lee W. Hartmann; 4. Planetary habitability on astronomical time scales Donald E. Brownlee; 5. Solar internal flows and dynamo action Mark S. Miesch; 6. Modeling solar and stellar dynamos Paul Charbonneau; 7. Planetary fields and dynamos Ulrich R. Christensen; 8. The structure and evolution of the 3D solar wind John T. Gosling; 9. The heliosphere and cosmic rays J. Randy Jokipii; 10. Solar spectral irradiance: measurements and models Judith L. Lean and Thomas N. Woods; 11. Astrophysical influences on planetary climate systems Juerg Beer; 12. Evaluating the drivers of Earth's climate system Thomas J. Crowley; 13. Ionospheres of the terrestrial planets Stanley C. Solomon; 14. Long-term evolution of the geospace climate Jan J. Sojka; 15. Waves and transport processes in atmospheres and oceans Richard L. Walterscheid; 16. Solar variability, climate, and atmospheric photochemistry Guy P. Brasseur, Daniel Marsch and Hauke Schmidt; Appendix I. Authors and editors; List of illustrations; List of tables; Bibliography; Index.

Heliophysics: Evolving Solar Activity and the Climates of Space and Earth

NASA Astrophysics Data System (ADS)

Schrijver, Carolus J.; Siscoe, George L.

2012-01-01

Preface; 1. Interconnectedness in heliophysics Carolus J. Schrijver and George L. Siscoe; 2. Long-term evolution of magnetic activity of Sun-like stars Carolus J. Schrijver; 3. Formation and early evolution of stars and proto-planetary disks Lee W. Hartmann; 4. Planetary habitability on astronomical time scales Donald E. Brownlee; 5. Solar internal flows and dynamo action Mark S. Miesch; 6. Modeling solar and stellar dynamos Paul Charbonneau; 7. Planetary fields and dynamos Ulrich R. Christensen; 8. The structure and evolution of the 3D solar wind John T. Gosling; 9. The heliosphere and cosmic rays J. Randy Jokipii; 10. Solar spectral irradiance: measurements and models Judith L. Lean and Thomas N. Woods; 11. Astrophysical influences on planetary climate systems Juerg Beer; 12. Evaluating the drivers of Earth's climate system Thomas J. Crowley; 13. Ionospheres of the terrestrial planets Stanley C. Solomon; 14. Long-term evolution of the geospace climate Jan J. Sojka; 15. Waves and transport processes in atmospheres and oceans Richard L. Walterscheid; 16. Solar variability, climate, and atmospheric photochemistry Guy P. Brasseur, Daniel Marsch and Hauke Schmidt; Appendix I. Authors and editors; List of illustrations; List of tables; Bibliography; Index.

The American College of Academic International Medicine 2017 Consensus Statement on International Medical Programs: Establishing a system of objective valuation and quantitative metrics to facilitate the recognition and incorporation of academic international medical efforts into existing promotion and tenure paradigms

PubMed Central

Peck, Gregory L.; Garg, Manish; Arquilla, Bonnie; Gracias, Vicente H.; Anderson III, Harry L.; Miller, Andrew C.; Hansoti, Bhakti; Ferrada, Paula; Firstenberg, Michael S.; Galwankar, Sagar C.; Gist, Ramon E.; Jeanmonod, Donald; Jeanmonod, Rebecca; Krebs, Elizabeth; McDonald, Marian P.; Nwomeh, Benedict; Orlando, James P.; Paladino, Lorenzo; Papadimos, Thomas J.; Ricca, Robert L.; Sakran, Joseph V.; Sharpe, Richard P.; Swaroop, Mamta; Stawicki, Stanislaw P.

2017-01-01

The growth of academic international medicine (AIM) as a distinct field of expertise resulted in increasing participation by individual and institutional actors from both high-income and low-and-middle-income countries. This trend resulted in the gradual evolution of international medical programs (IMPs). With the growing number of students, residents, and educators who gravitate toward nontraditional forms of academic contribution, the need arose for a system of formalized metrics and quantitative assessment of AIM- and IMP-related efforts. Within this emerging paradigm, an institution's “return on investment” from faculty involvement in AIM and participation in IMPs can be measured by establishing equivalency between international work and various established academic activities that lead to greater institutional visibility and reputational impact. The goal of this consensus statement is to provide a basic framework for quantitative assessment and standardized metrics of professional effort attributable to active faculty engagement in AIM and participation in IMPs. Implicit to the current work is the understanding that the proposed system should be flexible and adaptable to the dynamically evolving landscape of AIM – an increasingly important subset of general academic medical activities. PMID:29291172

International Laser Ranging Service (ILRS) 2003-2004 Annual Report

NASA Technical Reports Server (NTRS)

Pearlman, Michael (Editor); Noll, Carey (Editor)

2005-01-01

The International Laser Ranging Service (ILRS) organizes and coordinates Satellite Laser Ranging (SLR) and Lunar Laser Ranging (LLR) to support programs in geodetic, geophysical, and lunar research activities and provides the International Earth Rotation and Reference Systems Service (IERS) with products important to the maintenance of an accurate International Terrestrial Reference Frame (ITRF). This reference frame provides the stability through which systematic measurements of the Earth can be made over thousands of kilometers, decades of time, and evolution of measurement technology. This 2003-2004 ILRS annual report is comprised of individual contributions from ILRS components within the international geodetic community for the years 2003-2004. The report documents changes and progress of the ILRS and is also available on the ILRS Web site at http://ilrs.gsfc.nasa.gov/reports/ilrs_reports/ilrsar_2003.html.

Network evolution model for supply chain with manufactures as the core.

PubMed

Fang, Haiyang; Jiang, Dali; Yang, Tinghong; Fang, Ling; Yang, Jian; Li, Wu; Zhao, Jing

2018-01-01

Building evolution model of supply chain networks could be helpful to understand its development law. However, specific characteristics and attributes of real supply chains are often neglected in existing evolution models. This work proposes a new evolution model of supply chain with manufactures as the core, based on external market demand and internal competition-cooperation. The evolution model assumes the external market environment is relatively stable, considers several factors, including specific topology of supply chain, external market demand, ecological growth and flow conservation. The simulation results suggest that the networks evolved by our model have similar structures as real supply chains. Meanwhile, the influences of external market demand and internal competition-cooperation to network evolution are analyzed. Additionally, 38 benchmark data sets are applied to validate the rationality of our evolution model, in which, nine manufacturing supply chains match the features of the networks constructed by our model.

Network evolution model for supply chain with manufactures as the core

PubMed Central

Jiang, Dali; Fang, Ling; Yang, Jian; Li, Wu; Zhao, Jing

2018-01-01

Building evolution model of supply chain networks could be helpful to understand its development law. However, specific characteristics and attributes of real supply chains are often neglected in existing evolution models. This work proposes a new evolution model of supply chain with manufactures as the core, based on external market demand and internal competition-cooperation. The evolution model assumes the external market environment is relatively stable, considers several factors, including specific topology of supply chain, external market demand, ecological growth and flow conservation. The simulation results suggest that the networks evolved by our model have similar structures as real supply chains. Meanwhile, the influences of external market demand and internal competition-cooperation to network evolution are analyzed. Additionally, 38 benchmark data sets are applied to validate the rationality of our evolution model, in which, nine manufacturing supply chains match the features of the networks constructed by our model. PMID:29370201

Evolution of Time Scales

DTIC Science & Technology

2006-12-01

as the fundamental unit of time in the International System of Units. It was defined as ( Metrologia , 1968) “the duration of 9 192 631 770 periods of...atomic time equivalent to the second of ET in principle. The Comité Consultatif pour la Définition de la Seconde (CCDS) of the CIPM recommended...with the definition of the second, the unit of time of the Inter- national System of Units” ( Metrologia , 1971). The CCDS (BIPM Com. Cons. Déf. Seconde

Hybrid Multiagent System for Automatic Object Learning Classification

NASA Astrophysics Data System (ADS)

Gil, Ana; de La Prieta, Fernando; López, Vivian F.

The rapid evolution within the context of e-learning is closely linked to international efforts on the standardization of learning object metadata, which provides learners in a web-based educational system with ubiquitous access to multiple distributed repositories. This article presents a hybrid agent-based architecture that enables the recovery of learning objects tagged in Learning Object Metadata (LOM) and provides individualized help with selecting learning materials to make the most suitable choice among many alternatives.

CD-ROM Proceedings International Symposium on Erosion and Landscape Evolution (ISELE)

USDA-ARS?s Scientific Manuscript database

This CD-ROM contains the abstracts and full papers for the proceedings from the ASABE specialty conference, the International Symposium on Erosion and Landscape Evolution (ISELE), held September 18-21, 2011 at the Hilton Anchorage Hotel in Anchorage, Alaska. Three extended abstracts from the meeting...

[Historic and functional biology: the inadequacy of a system theory of evolution].

PubMed

Regelmann, J P

1982-01-01

In the first half of the 20th century neo-Kantianism in a broad sense proved itself the main conceptual and methodological background of the central European biology. As such it contributed much to the victory on the typological, idealistic-morphological and psycho-vitalistic interpretations of life. On the other hand it could not give tools to the biologists for working out a strictly darwinian evolution theory. Kant's theory of organism was conceived without evolution as a theory of the internal functionality of the organism. There was only some 'play' with the evolutionary differentiation of the species. Since then the disputes around the work of August Weismann, a synthetical evolution theory which is now behind time, arose. This theory developed from coinciding claims, elaborated by geneticists, mathematicians, and by biologists studying development, natural history and systematics. This was done under a strong influence of marxist ideas. Through the interweaving of such different approaches it was possible for this evolutionary synthesis to influence successfully the development of evolution research during more than 40 years. Philosophically speaking modern evolution theory means therefore an aversion, even a positive abolition of Kantian positions. A number of biologists however--as L. von Bertalanffy--refused to adhere to a misinterpreted Kantian methodology and oriented themselves to an approach via system theory, which obtained a place in evolution research. In fact this is a Kantian approach as well. They only repeated the Kantian dilemma of the evolution which can also be found in Lamarck and Hegel. The system theory of the functionality of the organism never reaches to the level of the evolving species, but remains always on the level of epigenetic thinking, because of its philosophical origin. This paper points out the consequences of this still current dilemma. At the same time an all-enclosing reflection on the methodological, epistemological and the important historical questions of evolutionary biology in its scientific context is recommended.

Evolution of time-keeping mechanisms: early emergence and adaptation to photoperiod

PubMed Central

Hut, R. A.; Beersma, D. G. M.

2011-01-01

Virtually all species have developed cellular oscillations and mechanisms that synchronize these cellular oscillations to environmental cycles. Such environmental cycles in biotic (e.g. food availability and predation risk) or abiotic (e.g. temperature and light) factors may occur on a daily, annual or tidal time scale. Internal timing mechanisms may facilitate behavioural or physiological adaptation to such changes in environmental conditions. These timing mechanisms commonly involve an internal molecular oscillator (a ‘clock’) that is synchronized (‘entrained’) to the environmental cycle by receptor mechanisms responding to relevant environmental signals (‘Zeitgeber’, i.e. German for time-giver). To understand the evolution of such timing mechanisms, we have to understand the mechanisms leading to selective advantage. Although major advances have been made in our understanding of the physiological and molecular mechanisms driving internal cycles (proximate questions), studies identifying mechanisms of natural selection on clock systems (ultimate questions) are rather limited. Here, we discuss the selective advantage of a circadian system and how its adaptation to day length variation may have a functional role in optimizing seasonal timing. We discuss various cases where selective advantages of circadian timing mechanisms have been shown and cases where temporarily loss of circadian timing may cause selective advantage. We suggest an explanation for why a circadian timing system has emerged in primitive life forms like cyanobacteria and we evaluate a possible molecular mechanism that enabled these bacteria to adapt to seasonal variation in day length. We further discuss how the role of the circadian system in photoperiodic time measurement may explain differential selection pressures on circadian period when species are exposed to changing climatic conditions (e.g. global warming) or when they expand their geographical range to different latitudes or altitudes. PMID:21690131

A coupled modeling framework of the co-evolution of humans and water: case study of Tarim River Basin, western China

NASA Astrophysics Data System (ADS)

Liu, D.; Tian, F.; Lin, M.; Sivapalan, M.

2014-04-01

The complex interactions and feedbacks between humans and water are very essential issues but are poorly understood in the newly proposed discipline of socio-hydrology (Sivapalan et al., 2012). An exploratory model with the appropriate level of simplification can be valuable to improve our understanding of the co-evolution and self-organization of socio-hydrological systems driven by interactions and feedbacks operating at different scales. In this study, a simple coupled modeling framework for socio-hydrology co-evolution is developed for the Tarim River Basin in Western China, and is used to illustrate the explanatory power of such a model. The study area is the mainstream of the Tarim River, which is divided into two modeling units. The socio-hydrological system is composed of four parts, i.e. social sub-system, economic sub-system, ecological sub-system, and hydrological sub-system. In each modeling unit, four coupled ordinary differential equations are used to simulate the dynamics of the social sub-system represented by human population, the economic sub-system represented by irrigated crop area, the ecological sub-system represented by natural vegetation cover and the hydrological sub-system represented by stream discharge. The coupling and feedback processes of the four dominant sub-systems (and correspondingly four state variables) are integrated into several internal system characteristics interactively and jointly determined by themselves and by other coupled systems. For example, the stream discharge is coupled to the irrigated crop area by the colonization rate and mortality rate of the irrigated crop area in the upper reach and the irrigated area is coupled to stream discharge through irrigation water consumption. In a similar way, the stream discharge and natural vegetation cover are coupled together. The irrigated crop area is coupled to human population by the colonization rate and mortality rate of the population. The inflow of the lower reach is determined by the outflow from the upper reach. The natural vegetation cover in the lower reach is coupled to the outflow from the upper reach and governed by regional water resources management policy. The co-evolution of the Tarim socio-hydrological system is then analyzed within this modeling framework to gain insights into the overall system dynamics and its sensitivity to the external drivers and internal system variables. In the modeling framework, the state of each subsystem is holistically described by one state variable and the framework is flexible enough to comprise more processes and constitutive relationships if they are needed to illustrate the interaction and feedback mechanisms of the human-water system.

Modeling the effect of subgrain rotation recrystallization on the evolution of olivine crystal preferred orientations in simple shear

NASA Astrophysics Data System (ADS)

Signorelli, Javier; Tommasi, Andréa

2015-11-01

Homogenization models are widely used to predict the evolution of texture (crystal preferred orientations) and resulting anisotropy of physical properties in metals, rocks, and ice. They fail, however, in predicting two main features of texture evolution in simple shear (the dominant deformation regime on Earth) for highly anisotropic crystals, like olivine: (1) the fast rotation of the CPO towards a stable position characterized by parallelism of the dominant slip system and the macroscopic shear and (2) the asymptotical evolution towards a constant intensity. To better predict CPO-induced anisotropy in the mantle, but limiting computational costs and use of poorly-constrained physical parameters, we modified a viscoplastic self-consistent code to simulate the effects of subgrain rotation recrystallization. To each crystal is associated a finite number of fragments (possible subgrains). Formation of a subgrain corresponds to introduction of a disorientation (relative to the parent) and resetting of the fragment strain and internal energy. The probability of formation of a subgrain is controlled by comparison between the local internal energy and the average value in the polycrystal. A two-level mechanical interaction scheme is applied for simulating the intracrystalline strain heterogeneity allowed by the formation of low-angle grain boundaries. Within a crystal, interactions between subgrains follow a constant stress scheme. The interactions between grains are simulated by a tangent viscoplastic self-consistent approach. This two-level approach better reproduces the evolution of olivine CPO in simple shear in experiments and nature. It also predicts a marked weakening at low shear strains, consistently with experimental data.

Generation and propagation of nonlinear internal waves in Massachusetts Bay

USGS Publications Warehouse

Scotti, A.; Beardsley, R.C.; Butman, B.

2007-01-01

During the summer, nonlinear internal waves (NLIWs) are commonly observed propagating in Massachusetts Bay. The topography of the area is unique in the sense that the generation area (over Stellwagen Bank) is only 25 km away from the shoaling area, and thus it represents an excellent natural laboratory to study the life cycle of NLIWs. To assist in the interpretation of the data collected during the 1998 Massachusetts Bay Internal Wave Experiment (MBIWE98), a fully nonlinear and nonhydrostatic model covering the generation/shoaling region was developed, to investigate the response of the system to the range of background and driving conditions observed. Simplified models were also used to elucidate the role of nonlinearity and dispersion in shaping the NLIW field. This paper concentrates on the generation process and the subsequent evolution in the basin. The model was found to reproduce well the range of propagation characteristics observed (arrival time, propagation speed, amplitude), and provided a coherent framework to interpret the observations. Comparison with a fully nonlinear hydrostatic model shows that during the generation and initial evolution of the waves as they move away from Stellwagen Bank, dispersive effects play a negligible role. Thus the problem can be well understood considering the geometry of the characteristics along which the Riemann invariants of the hydrostatic problem propagate. Dispersion plays a role only during the evolution of the undular bore in the middle of Stellwagen Basin. The consequences for modeling NLIWs within hydrostatic models are briefly discussed at the end.

Nature and Purpose of the International Symposium on Life-Long Education (Paris, September 25 - October 2, 1972).

ERIC Educational Resources Information Center

United Nations Educational, Scientific, and Cultural Organization, Paris (France).

The first working paper for UNESCO's Interdisciplinary Symposium on Life-long Education summarizes for participants some of the problems arising from the evolution of educational systems in the direction of lifelong education, some of the basic issues involved, and some of the requirements it meets and the consequences it may have. The areas…

The Big 5: The Evolution of the Performance Systems Model

ERIC Educational Resources Information Center

Tosti, Donald T.

2005-01-01

Human Performance Technology (HPT) consists of a few principles and a host of applications. The power of HPT comes from the fact that it is fundamental to an understanding of all forms of purposeful activity, ranging from the actions of an individual to the actions of an international organization. As a practical discipline, HPT began some 40…

French Universities at a Crossroads between Crisis and Radical Reform: Toward a New Academic Regime?

ERIC Educational Resources Information Center

Derouet, Jean-Louis; Normand, Romuald

2008-01-01

The recent evolution of the French higher education system is somehow in line with the new European and international environment, although what is specific to a national context should not be ignored. Admittedly, the public allocation of resources to universities is not challenged, the redistribution of funds is still based on an egalitarian…

Software development, nomenclature schemes, and mapping strategies for an international pediatric cardiac surgery database system.

PubMed

Jacobs, Jeffrey P

2002-01-01

The field of congenital heart surgery has the opportunity to create the first comprehensive international database for a medical subspecialty. An understanding of the demographics of congenital heart disease and the rapid growth of computer technology leads to the realization that creating a comprehensive international database for pediatric cardiac surgery represents an important and achievable goal. The evolution of computer-based data analysis creates an opportunity to develop software to manage an international congenital heart surgery database and eventually become an electronic medical record. The same database data set for congenital heart surgery is now being used in Europe and North America. Additional work is under way to involve Africa, Asia, Australia, and South America. The almost simultaneous publication of the European Association for Cardio-thoracic Surgery/Society of Thoracic Surgeons coding system and the Association for European Paediatric Cardiology coding system resulted in the potential for multiple coding. Representatives of the Association for European Paediatric Cardiology, Society of Thoracic Surgeons, European Association for Cardio-thoracic Surgery, and European Congenital Heart Surgeons Foundation agree that these hierarchical systems are complementary and not competitive. An international committee will map the two systems. The ideal coding system will permit a diagnosis or procedure to be coded only one time with mapping allowing this code to be used for patient care, billing, practice management, teaching, research, and reporting to governmental agencies. The benefits of international data gathering and sharing are global, with the long-term goal of the continued upgrade in the quality of congenital heart surgery worldwide. Copyright 2002 by W.B. Saunders Company

NMR implementation of adiabatic SAT algorithm using strongly modulated pulses.

PubMed

Mitra, Avik; Mahesh, T S; Kumar, Anil

2008-03-28

NMR implementation of adiabatic algorithms face severe problems in homonuclear spin systems since the qubit selective pulses are long and during this period, evolution under the Hamiltonian and decoherence cause errors. The decoherence destroys the answer as it causes the final state to evolve to mixed state and in homonuclear systems, evolution under the internal Hamiltonian causes phase errors preventing the initial state to converge to the solution state. The resolution of these issues is necessary before one can proceed to implement an adiabatic algorithm in a large system where homonuclear coupled spins will become a necessity. In the present work, we demonstrate that by using "strongly modulated pulses" (SMPs) for the creation of interpolating Hamiltonian, one can circumvent both the problems and successfully implement the adiabatic SAT algorithm in a homonuclear three qubit system. This work also demonstrates that the SMPs tremendously reduce the time taken for the implementation of the algorithm, can overcome problems associated with decoherence, and will be the modality in future implementation of quantum information processing by NMR.

Asteroid Evolution: Role of geotechnical properties

NASA Astrophysics Data System (ADS)

Sanchez Lana, Diego P.

2015-08-01

Over the last decade of Planetary research, the scientific community has made many advances in their understanding of the evolution of asteroids in the Solar System. One particular area of fruitful study started with the bold idea that these small planetary bodies could be gravitational aggregates and initially motivated by several different observations and early simulations.If we start with the idea that asteroids are aggregates of different sized components, and not singular monolithic bodies, it is possible to study them with some of the tools that have been used in the fields of Soil Mechanics and Granular Dynamics. In them, parameters such as porosity, cohesive and tensile strength, angles of friction and repose, particle size distributions, stress states, heterogeneity and yield criteria among others, determine how these granular systems will react when subjected to different, changing, external factors. These external factors are believed to have produced and shaped the asteroids that now exist around us and include solar photon momentum, gravitational tides, micro- and macro-impacts and internal energy dissipation.In this presentation we will review what is known about the surface and interiors of rubble pile asteroids, how different theoretical, experimental and simulation tools have been used to study them, how space mission and ground-based observations have shaped our understanding of their physical reality, and what we expect to learn from future missions. The talk will also touch on some of the latest findings obtained by different groups. In particular we will discuss the rotational evolution of self-gravitating aggregates under the influence of the YORP effect and how their angles of friction, tensile strength, porosity, internal structure and density give rise to different disruption modes and the role they play in the formation of asteroids pairs, tumblers and binary systems.

Gas Evolution from Insulating Materials for Superconducting Coil of Iter by Gamma Ray Irradiation at Liquid Nitrogen Temperature

NASA Astrophysics Data System (ADS)

Idesaki, A.; Koizumi, N.; Sugimoto, M.; Morishita, N.; Ohshima, T.; Okuno, K.

2008-03-01

A laminated material composed of glass cloth/polyimide film/epoxy resin will be used as an insulating material for superconducting coil of International Thermonuclear Experimental Reactor (ITER). In order to keep safe and stable operation of the superconducting coil system, it is indispensable to evaluate radiation resistance of the material, because the material is exposed to severe environments such as high radiation field and low temperature of 4 K. Especially, it is important to estimate the amount of gases evolved from the insulating material by irradiation, because the gases affect on the purifying system of liquid helium in the superconducting coil system. In this work, the gas evolution from the laminated material by gamma ray irradiation at liquid nitrogen temperature (77 K) was investigated, and the difference of gas evolution behavior due to difference of composition in the epoxy resin was discussed. It was found that the main gases evolved from the laminated material by the irradiation were hydrogen, carbon monoxide and carbon dioxide, and that the amount of gases evolved from the epoxy resin containing cyanate ester was about 60% less than that from the epoxy resin containing tetraglycidyl-diaminophenylmethane (TGDDM).

Multiplicity in Early Stellar Evolution

NASA Astrophysics Data System (ADS)

Reipurth, B.; Clarke, C. J.; Boss, A. P.; Goodwin, S. P.; Rodríguez, L. F.; Stassun, K. G.; Tokovinin, A.; Zinnecker, H.

Observations from optical to centimeter wavelengths have demonstrated that multiple systems of two or more bodies is the norm at all stellar evolutionary stages. Multiple systems are widely agreed to result from the collapse and fragmentation of cloud cores, despite the inhibiting influence of magnetic fields. Surveys of class 0 protostars with millimeter interferometers have revealed a very high multiplicity frequency of about 2/3, even though there are observational difficulties in resolving close protobinaries, thus supporting the possibility that all stars could be born in multiple systems. Near-infrared adaptive optics observations of class I protostars show a lower binary frequency relative to the class 0 phase, a declining trend that continues through the class II/III stages to the field population. This loss of companions is a natural consequence of dynamical interplay in small multiple systems, leading to ejection of members. We discuss observational consequences of this dynamical evolution, and its influence on circumstellar disks, and we review the evolution of circumbinary disks and their role in defining binary mass ratios. Special attention is paid to eclipsing PMS binaries, which allow for observational tests of evolutionary models of early stellar evolution. Many stars are born in clusters and small groups, and we discuss how interactions in dense stellar environments can significantly alter the distribution of binary separations through dissolution of wider binaries. The binaries and multiples we find in the field are the survivors of these internal and external destructive processes, and we provide a detailed overview of the multiplicity statistics of the field, which form a boundary condition for all models of binary evolution. Finally, we discuss various formation mechanisms for massive binaries, and the properties of massive trapezia.

Investigation of polymer electrolyte membrane fuel cell internal behaviour during long term operation and its use in prognostics

NASA Astrophysics Data System (ADS)

Mao, Lei; Jackson, Lisa; Jackson, Tom

2017-09-01

This paper investigates the polymer electrolyte membrane (PEM) fuel cell internal behaviour variation at different operating condition, with characterization test data taken at predefined inspection times, and uses the determined internal behaviour evolution to predict the future PEM fuel cell performance. For this purpose, a PEM fuel cell behaviour model is used, which can be related to various fuel cell losses. By matching the model to the collected polarization curves from the PEM fuel cell system, the variation of fuel cell internal behaviour can be obtained through the determined model parameters. From the results, the source of PEM fuel cell degradation during its lifetime at different conditions can be better understood. Moreover, with determined fuel cell internal behaviour, the future fuel cell performance can be obtained by predicting the future model parameters. By comparing with prognostic results using adaptive neuro fuzzy inference system (ANFIS), the proposed prognostic analysis can provide better predictions for PEM fuel cell performance at dynamic condition, and with the understanding of variation in PEM fuel cell internal behaviour, mitigation strategies can be designed to extend the fuel cell performance.

Online Planetary Science Courses at Athabasca University

NASA Astrophysics Data System (ADS)

Connors, Martin; Munyikwa, Ken; Bredeson, Christy

2016-01-01

Athabasca University offers distance education courses in science, at freshman and higher levels. It has a number of geology and astronomy courses, and recently opened a planetary science course as the first upper division astronomy course after many years of offering freshman astronomy. Astronomy 310, Planetary Science, focuses on process in the Solar System on bodies other than Earth. This process-oriented course uses W. F. Hartmann's "Moons and Planets" as its textbook. It primarily approaches the subject from an astronomy and physics perspective. Geology 415, Earth's Origin and Early Evolution, is based on the same textbook, but explores the evidence for the various processes, events, and materials involved in the formation and evolution of Earth. The course provides an overview of objects in the Solar System, including the Sun, the planets, asteroids, comets, and meteoroids. Earth's place in the solar system is examined and physical laws that govern the motion of objects in the universe are looked at. Various geochemical tools and techniques used by geologists to reveal and interpret the evidence for the formation and evolution of bodies in the solar system as well as the age of earth are also explored. After looking at lines of evidence used to reconstruct the evolution of the solar system, processes involved in the formation of planets and stars are examined. The course concludes with a look at the origin and nature of Earth's internal structure. GEOL415 is a senior undergraduate course and enrols about 15-30 students annually. The courses are delivered online via Moodle and student evaluation is conducted through assignments and invigilated examinations.

Learning and Collective Knowledge Construction With Social Media: A Process-Oriented Perspective

PubMed Central

Kimmerle, Joachim; Moskaliuk, Johannes; Oeberst, Aileen; Cress, Ulrike

2015-01-01

Social media are increasingly being used for educational purposes. The first part of this article briefly reviews literature that reports on educational applications of social media tools. The second part discusses theories that may provide a basis for analyzing the processes that are relevant for individual learning and collective knowledge construction. We argue that a systems-theoretical constructivist approach is appropriate to examine the processes of educational social media use, namely, self-organization, the internalization of information, the externalization of knowledge, and the interplay of externalization and internalization providing the basis of a co-evolution of cognitive and social systems. In the third part we present research findings that illustrate and support this systems-theoretical framework. Concluding, we discuss the implications for educational design and for future research on learning and collective knowledge construction with social media. PMID:26246643

NASA study grants

NASA Astrophysics Data System (ADS)

To expand human exploration of the Solar System, the Office of Exploration of the National Aeronautics and Space Administration has awarded 20 contracts for ideas, concepts, devices, systems, and trajectory, operation and implementation plans. Winning proposals came from five industry-related firms, two organizations in the space-support business, and thirteen universities; they were chosen from 115 entries.Geophysical studies to be supported include site characterization of the Oregon moonbase (Oregon L-5 Society, Inc., Oregon City), evolution of design alternatives for exploration of Mars by balloon (Titan Systems, Inc., San Diego, Calif.), design considerations of a lunar production plant (Boston University, Chestnut Hill, Mass.), planetary materials and resource utilization (Michigan Technological University, Houghton), Mars tethered sample return study (University of Colorado, Boulder), Teleprospector, a teleoperated robotic field geologist (University of New Mexico, Albuquerque), and the International Lunar Polar Orbiter (International Space University, Boston, Mass.).

49 CFR 173.24 - General requirements for packagings and packages.

Code of Federal Regulations, 2010 CFR

2010-10-01

...) Combustion or dangerous evolution of heat; (ii) Evolution of flammable, poisonous, or asphyxiant gases; or... by the evolution of gas from the contents, is permitted only when— (1) Except for shipments of... required to reduce internal pressure that may develop by the evolution of gas subject to the requirements...

49 CFR 173.24 - General requirements for packagings and packages.

Code of Federal Regulations, 2013 CFR

2013-10-01

...) Combustion or dangerous evolution of heat; (ii) Evolution of flammable, poisonous, or asphyxiant gases; or... by the evolution of gas from the contents, is permitted only when— (1) Except for shipments of... required to reduce internal pressure that may develop by the evolution of gas subject to the requirements...

49 CFR 173.24 - General requirements for packagings and packages.

Code of Federal Regulations, 2012 CFR

2012-10-01

...) Combustion or dangerous evolution of heat; (ii) Evolution of flammable, poisonous, or asphyxiant gases; or... by the evolution of gas from the contents, is permitted only when— (1) Except for shipments of... required to reduce internal pressure that may develop by the evolution of gas subject to the requirements...

49 CFR 173.24 - General requirements for packagings and packages.

Code of Federal Regulations, 2014 CFR

2014-10-01

...) Combustion or dangerous evolution of heat; (ii) Evolution of flammable, poisonous, or asphyxiant gases; or... by the evolution of gas from the contents, is permitted only when— (1) Except for shipments of... required to reduce internal pressure that may develop by the evolution of gas subject to the requirements...

Effects of initial amplitude and pycnocline thickness on the evolution of mode-2 internal solitary waves

NASA Astrophysics Data System (ADS)

Cheng, Ming-Hung; Hsieh, Chih-Min; Hwang, Robert R.; Hsu, John R.-C.

2018-04-01

Numerical simulations are performed to investigate the effects of the initial amplitude and pycnocline thickness on the evolutions of convex mode-2 internal solitary waves propagating on the flat bottom. A finite volume method based on a Cartesian grid system is adopted to solve the Navier-Stokes equations using the improved delayed detached eddy simulation turbulent closure model. Mode-2 internal solitary waves (ISWs) are found to become stable at t = 15 s after lifting a vertical sluice gate by a gravity collapse mechanism. Numerical results from three cases of pycnocline thickness reveal the following: (1) the occurrence of a smooth mode-2 ISW when the wave amplitude is small; (2) the PacMan phenomenon for large amplitude waves; and (3) pseudo vortex shedding in the case of very large amplitudes. In general, basic wave properties (wave amplitude, wave speed, vorticity, and wave energy) increase as the wave amplitude increases for a specific value of the pycnocline thickness. Moreover, the pycnocline thickness chiefly determines the core size of a convex mode-2 ISW, while the step depth (that generates an initial wave amplitude) and offset in pycnocline govern the waveform type during its propagation on the flat bottom.

Fostering International Collaboration in Birth Defects Research and Prevention: A Perspective From the International Clearinghouse for Birth Defects Surveillance and Research

PubMed Central

Botto, Lorenzo D.; Robert-Gnansia, Elisabeth; Siffel, Csaba; Harris, John; Borman, Barry; Mastroiacovo, Pierpaolo

2006-01-01

The International Clearing-house for Birth Defects Surveillance and Research, formerly known as International Clearinghouse of Birth Defects Monitoring Systems, consists of 40 registries worldwide that collaborate in monitoring 40 types of birth defects. Clearinghouse activities include the sharing and joint monitoring of birth defect data, epidemiologic and public health research, and capacity building, with the goal of reducing disease and promoting healthy birth outcomes through primary prevention. We discuss 3 of these activities: the collaborative assessment of the potential teratogenicity of first-trimester use of medications (the MADRE project), an example of the intersection of surveillance and research; the international databases of people with orofacial clefts, an example of the evolution from surveillance to outcome research; and the study of genetic polymorphisms, an example of collaboration in public health genetics. PMID:16571708

Formation and Internal Structure of Terrestrial Planets, and Atmospheric Escape

NASA Astrophysics Data System (ADS)

Jin, S.

2014-11-01

As of 2014 April 21, over 1490 confirmed exoplanets and 3705 Kepler candidates have been detected. This implies that exoplanets may be ubiquitous in the universe. In this paper, we focus on the formation, evolution, and internal structure of terrestrial planets, and the atmospheric escape of close-in planets. In chapter 2, we investigate the dynamical evolution of planetary system after the protoplanetary disk has dissipated. We find that in the final assembly stage, the occurrence of terrestrial planets is quite common and in 40% of our simulations finally at least one planet is formed in the habitable zone. We also find that if there is a highly-inclined giant planet in the system, a great many bodies will be either driven out of the system, or collide with the giant planet or the central star. This will lead to the difficulty in planetary accretion. Moreover, our results show that planetary migration can lead to the formation of close-in planets. Besides migration, close-in terrestrial planets can also be formed by a collision-merger mechanism, which means that planetary embryos can kick terrestrial planets directly into orbits that are extremely close to their parent stars. In chapter 3, we construct numerically an internal structure model for terrestrial planets, and provide three kinds of possible internal structures of Europa (Jupiter's moon) based on this model. Then, we calculate the radii of low-mass exoplanets for various mass combinations of core and mantle, and find that some of them are inconsistent with the observed radius of rocky planets. This phenomenon can be explained only if there exists a large amount of water in the core, or they own gaseous envelopes. In chapter 4, we improve our planetary evolution codes using the semi-gray model of Guillot (2010), which includes the incident flux from the host star as a heating source in planetary atmosphere. The updated codes can solve the structure of the top radiative zone of intensely irradiated planets, and thus can simulate the atmospheric escape of close-in planets driven by strong stellar X-ray or EUV emissions. We find that low-mass planets are sensitive to the atmospheric escape, and they could lose all their initial H/He envelopes during the evolution. On the other hand, gas giant can only lose a small fraction of their initial envelopes. We then carry out a parameter study of atmospheric escape at the planetary core mass, envelope mass fraction, and semi-major axis space. We find that the most intense phase of evaporation occurs within the early 100 Myr. Afterwards, atmospheric escape only has a small impact on the planetary evolution. In chapter 5, we apply our new planetary evolution model to different synthetic planet populations that are directly produced by the core-accretion paradigm (Mordasini et al. 2012a,b). We show that although the mass distribution of the planet populations is hardly affected by evaporation, the radius distribution clearly shows a break around 2 R_{⊕}. This break leads to a bimodal distribution in planet sizes (Owen & Wu 2013). Furthermore, the bimodal distribution is related to the initial characteristics of the planetary populations. We find that in two extreme cases, namely without any evaporation or with a 100% heating efficiency in the evaporation model, the final radius distributions show significant differences compared to the radius distribution of Kepler candidates. In chapter 6, we introduce a radiative transfer model that can calculate the radiation spectrum of close-in exoplanets.

Adiabatic invariants in stellar dynamics. 1: Basic concepts

NASA Technical Reports Server (NTRS)

Weinberg, Martin D.

1994-01-01

The adiabatic criterion, widely used in astronomical dynamics, is based on the harmonic oscillator. It asserts that the change in action under a slowly varying perturbation is exponentially small. Recent mathematical results that precisely define the conditions for invariance show that this model does not apply in general. In particular, a slowly varying perturbation may cause significant evolution stellar dynamical systems even if its time scale is longer than any internal orbital time scale. This additional 'heating' may have serious implications for the evolution of star clusters and dwarf galaxies which are subject to long-term environmental forces. The mathematical developments leading to these results are reviewed, and the conditions for applicability to and further implications for stellar systems are discussed. Companion papers present a computational method for a general time-dependent disturbance and detailed example.

The signatures of the parental cluster on field planetary systems

NASA Astrophysics Data System (ADS)

Cai, Maxwell Xu; Portegies Zwart, Simon; van Elteren, Arjen

2018-03-01

Due to the high stellar densities in young clusters, planetary systems formed in these environments are likely to have experienced perturbations from encounters with other stars. We carry out direct N-body simulations of multiplanet systems in star clusters to study the combined effects of stellar encounters and internal planetary dynamics. These planetary systems eventually become part of the Galactic field population as the parental cluster dissolves, which is where most presently known exoplanets are observed. We show that perturbations induced by stellar encounters lead to distinct signatures in the field planetary systems, most prominently, the excited orbital inclinations and eccentricities. Planetary systems that form within the cluster's half-mass radius are more prone to such perturbations. The orbital elements are most strongly excited in the outermost orbit, but the effect propagates to the entire planetary system through secular evolution. Planet ejections may occur long after a stellar encounter. The surviving planets in these reduced systems tend to have, on average, higher inclinations and larger eccentricities compared to systems that were perturbed less strongly. As soon as the parental star cluster dissolves, external perturbations stop affecting the escaped planetary systems, and further evolution proceeds on a relaxation time-scale. The outer regions of these ejected planetary systems tend to relax so slowly that their state carries the memory of their last strong encounter in the star cluster. Regardless of the stellar density, we observe a robust anticorrelation between multiplicity and mean inclination/eccentricity. We speculate that the `Kepler dichotomy' observed in field planetary systems is a natural consequence of their early evolution in the parental cluster.

The evolution of communities in the international oil trade network

NASA Astrophysics Data System (ADS)

Zhong, Weiqiong; An, Haizhong; Gao, Xiangyun; Sun, Xiaoqi

2014-11-01

International oil trade is a subset of global trade and there exist oil trade communities. These communities evolve over time and provide clues of international oil trade patterns. A better understanding of the international oil trade patterns is necessary for governments in policy making. To study the evolution of trade communities in the international oil trade network, we set up unweighted and weighted oil trade network models based on complex network theory using data from 2002 to 2011. We detected the communities in the oil trade networks and analyzed their evolutionary properties and stabilities over time. We found that the unweighted and weighted international oil trade networks show many different features in terms of community number, community scale, distribution of countries, quality of partitions, and stability of communities. Two turning points occurred in the evolution of community stability in the international oil trade network. One is the year 2004-2005 which correlates with changes in demand and supply in the world oil market after the Iraq War, and the other is the year 2008-2009 which is connected to the 2008 financial crisis. Different causations of instability show different features and this should be considered by policy makers.

Overview of NASA's Earth Science Data Systems

NASA Technical Reports Server (NTRS)

McDonald, Kenneth

2004-01-01

For over the last 15 years, NASA's Earth Science Enterprise (ESE) has devoted a tremendous effort to design and build the Earth Observing System (EOS) Data and Information System (EOSDIS) to acquire, process, archive and distribute the data of the EOS series of satellites and other ESE missions and field programs. The development of EOSDIS began with an early prototype to support NASA data from heritage missions and progressed through a formal development process to today's system that supports the data from multiple missions including Landsat 7, Terra, Aqua, SORCE and ICESat. The system is deployed at multiple Distributed Active Archive Centers (DAACs) and its current holdings are approximately 4.5 petabytes. The current set of unique users requesting EOS data and information products exceeds 2 million. While EOSDIS has been the centerpiece of NASA's Earth Science Data Systems, other initiatives have augmented the services of EOSDIS and have impacted its evolution and the future directions of data systems within the ESE. ESDIS had an active prototyping effort and has continued to be involved in the activities of the Earth Science Technology Office (ESTO). In response to concerns from the science community that EOSDIS was too large and monolithic, the ESE initiated the Earth Science Information Partners (ESP) Federation Experiment that funded a series of projects to develop specialized products and services to support Earth science research and applications. Last year, the enterprise made 41 awards to successful proposals to the Research, Education and Applications Solutions Network (REASON) Cooperative Agreement Notice to continue and extend the ESP activity. The ESE has also sponsored a formulation activity called the Strategy for the Evolution of ESE Data Systems (SEEDS) to develop approaches and decision support processes for the management of the collection of data system and service providers of the enterprise. Throughout the development of its earth science data systems, NASA has had an active collaboration with a number of interagency and international partners. One of the mechanisms that has been extremely helpful in initiating and promoting this collaboration has been NASA's participation in the Committee on Earth Observation Satellites (CEOS) and its Working Group on Information Systems and Services (WGISS). The CEOS members, working together, have implemented an International Directory Network that enables users to locate collections of earth science data held by the international community and an International Catalog System to search and order specific data products. CEOS WGISS has also promoted the international interest in the Open GIS Consortium s specifications that further advance the access and use of geospatial data and the interoperation of GTS components. These are just a few highlights of the benefits that member agencies gain from CEOS participation.

The International DORIS Service (IDS) - Recent Developments in Preparation for ITRF2013

NASA Technical Reports Server (NTRS)

Willis, Pascal; Lemoine, Frank G.; Moreaux, Guilhem; Soudarin, Laurent; Ferrage, Pascale; Ries, John; Otten, Michiel; Saunier, Jerome; Noll, Carey E.; Biancale, Richard;

Socio-hydrologic Perspectives of the Co-evolution of Humans and Water in the Tarim River Basin, Western China

NASA Astrophysics Data System (ADS)

Liu, Ye; Tian, Fuqiang; Hu, Heping; Liu, Dengfeng; Sivapalan, Murugesu

2013-04-01

Socio-hydrology studies the co-evolution of coupled human-water systems, which is of great importance for long-term sustainable water resource management in basins suffering from serious eco-environmental degradation. Process socio-hydrology can benefit from the exploring the patterns of historical co-evolution of coupled human-water systems as a way to discovering the organizing principles that may underpin their co-evolution. As a self-organized entity, the human-water system in a river basin would evolve into certain steady states over a sufficiently long time but then could also experience sudden shifts due to internal or external disturbances that exceed system thresholds. In this study, we discuss three steady states (also called stages in the social sciences, including natural, human exploitation and recovery stages) and transitions between these during the past 1500 years in the Tarim River Basin of Western China, which a rich history of civilization including its place in the famous Silk Road that connected China to Europe. Specifically, during the natural stage with a sound environment that existed before the 19th century, shifts in the ecohydrological regime were mainly caused by environmental changes such river channel migration and climate change. During the human exploitation stages in the 5th and again in the 19th-20th centuries, however, humans gradually became the main drivers for system evolution, during which the basin experienced rapid population growth, fast socio-economic development and intense human activities. By the 1970s, after 200 years of colonization, the Tarim River Basin evolved into a new regime with vulnerable ecosystem and water system, and suffered from serious water shortages and desertification. Human society then began to take a critical look into the effects of their activities and reappraise the impact of human development on the ecohydrological system, which eventually led the basin into a treatment and recovery stage. Since then, the basin has shown a reverse trend of regime shift towards healing of the environmental damage that was inflicted in the previous stage of human development. In this paper we analyze the recasting effect of human activities on the water system and provide explanations on how human activities influence the co-evolution of human-water system from a broader perspective.

Ocean Drilling: Forty Years of International Collaboration

NASA Astrophysics Data System (ADS)

Smith, Deborah K.; Exon, Neville; Barriga, Fernando J. A. S.; Tatsumi, Yoshiyuki

2010-10-01

International cooperation is an essential component of modern scientific research and societal advancement [see Ismail-Zadeh and Beer, 2009], and scientific ocean drilling represents one of Earth science's longest-running and most successful international collaborations. The strength of this collaboration and its continued success result from the realization that scientific ocean drilling provides a unique and powerful tool to study the critical processes of both short-term change and the long-term evolution of Earth systems. A record of Earth's changing tectonics, climate, ocean circulation, and biota is preserved in marine sedimentary deposits and the underlying basement rocks. And because the ocean floor is the natural site for accumulation and preservation of geological materials, it may preserve a continuous record of these processes.

Internally Generated and Externally Forced Multidecadal Oceanic Modes and their Influence on the Summer Rainfall over East Asia

NASA Astrophysics Data System (ADS)

Si, D.; Hu, A.

2017-12-01

The interdecadal oceanic variabilities can be generated from both internal and external processes, and these variabilities can significantly modulate our climate on global and regional scale, such as the warming slowdown in the early 21st century, and the rainfall in East Asia. By analyzing simulations from a unique Community Earth System Model (CESM) Large Ensemble (CESM_LE) project, we show that the Interdecadal Pacific Oscillation (IPO) is primarily an internally generated oceanic variability, while the Atlantic Multidecadal Oscillation (AMO) may be an oceanic variability generated by internal oceanic processes and modulated by external forcings in the 20th century. Although the observed relationship between IPO and the Yangtze-Huaihe River valley (YHRV) summer rainfall in China is well simulated in both the preindustrial control and 20th century ensemble, none of the 20th century ensemble members can reproduce the observed time evolution of both IPO and YHRV due to the unpredictable nature of IPO on multidecade timescale. On the other hand, although CESM_LE cannot reproduce the observed relationship between AMO and Huanghe River valley (HRV) summer rainfall of China in the preindustrial control simulation, this relationship in the 20th century simulations is well reproduced, and the chance to reproduce the observed time evolution of both AMO and HRV rainfall is about 30%, indicating the important role of the interaction between the internal processes and the external forcing to realistically simulate the AMO and HRV rainfall.

Encouraging Reactivity to Create Robust Machines

DTIC Science & Technology

2013-07-01

Performance Evaluation and Benchmarking of Intelligent Systems, 113 137. Baldwin, J. (1896). A new factor in evolution. The American Naturalist, 30(355...Once more unto the breach: Co evolving a robot and its simulator. In Proceed ings of the international conference on artifical life (alife9) (pp.57...Pfeifer, R. (2003). Evolving complete agents using artificial ontogeny. In (pp. 237 258). Springer Verlag. Brooks, R. (1994). Artifical life and

Socio-hydrologic perspectives of the co-evolution of humans and water in the Tarim River basin, Western China: the Taiji-Tire model

NASA Astrophysics Data System (ADS)

Liu, Y.; Tian, F.; Hu, H.; Sivapalan, M.

2014-04-01

This paper presents a historical socio-hydrological analysis of the Tarim River basin (TRB), Xinjiang Uyghur Autonomous Region, in Western China, from the time of the opening of the Silk Road to the present. The analysis is aimed at exploring the historical co-evolution of coupled human-water systems and at identifying common patterns or organizing principles underpinning socio-hydrological systems (SHS). As a self-organized entity, the evolution of the human-water system in the Tarim Basin reached stable states for long periods of time, but then was punctuated by sudden shifts due to internal or external disturbances. In this study, we discuss three stable periods (i.e., natural, human exploitation, and degradation and recovery) and the transitions in between during the past 2000 years. During the "natural" stage that existed pre-18th century, with small-scale human society and sound environment, evolution of the SHS was mainly driven by natural environmental changes such as river channel migration and climate change. During the human exploitation stage, especially in the 19th and 20th centuries, it experienced rapid population growth, massive land reclamation and fast socio-economic development, and humans became the principal players of system evolution. By the 1970s, the Tarim Basin had evolved into a new regime with a vulnerable eco-hydrological system seemingly populated beyond its carrying capacity, and a human society that began to suffer from serious water shortages, land salinization and desertification. With intensified deterioration of river health and increased recognition of unsustainability of traditional development patterns, human intervention and recovery measures have since been adopted. As a result, the basin has shown a reverse regime shift towards some healing of the environmental damage. Based on our analysis within TRB and a common theory of social development, four general types of SHSs are defined according to their characteristic spatio-temporal variations of historical co-evolution, including primitive agricultural, traditional agricultural, industrial agricultural, and urban SHSs. These co-evolutionary changes have been explained in the paper in terms of the Taiji-Tire model, a refinement of a special concept in Chinese philosophy, relating to the co-evolution of a system because of interactions among its components.

Prediction of secondary generalization from a focal onset seizure in intracerebral EEG.

PubMed

Karthick, P A; Tanaka, Hideaki; Khoo, Hui Ming; Gotman, Jean

2018-05-01

We propose a system based on the first five seconds of intracerebrally recorded focal seizures to predict their evolution from focal to bilateral tonic-clonic seizure (FTC), to spread outside the onset zone but without tonic-clonic component (FS), or to a seizure remaining focal (F). Nineteen time and frequency domain features were extracted from 39 seizures of 32 patients and were subjected to support vector machine based classification. Three prediction approaches regarding seizure evolution were (1) FTC vs FS vs F, (2) FTC vs FS or F and (3) FTC or FS vs F. We used 21 seizures for training. Most features had significantly different distributions in the three seizure types (p < 0.05). Eighteen seizures were used for testing. We predicted the evolution of 12 seizures in FTC vs FS vs F, 13 seizures in FTC vs FS or F and 14 seizures in FTC or FS vs F. The first five seconds of a focal seizure contains information regarding the eventual evolution of the seizure, which could be predicted in most seizures. The proposed system could alert the health care team when a patient is hospitalized for intracerebral EEG and improve safety and eventually result in an implantable device. Copyright © 2018 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

International Space Station Evolution Data Book. Volume 2; Evolution Concepts; Revised

NASA Technical Reports Server (NTRS)

Jorgensen, Catherine A. (Editor); Antol, Jeffrey (Technical Monitor)

2000-01-01

This report provides a focused and in-depth look at the opportunities and drivers for the enhancement and evolution of the International Space Station (ISS) during assembly and beyond the assembly complete stage. These enhancements would expand and improve the current baseline capabilities of the ISS and help to facilitate the commercialization of the ISS by the private sector. Volume 1 provides the consolidated overview of the ISS baseline systems; information on the current facilities available for pressurized and unpressurized payloads; and information on current plans for crew availability and utilization, resource timelines and margin summaries including power, thermal, and storage volumes; and an overview of the vehicle traffic model. Volume 2 includes discussions of advanced technologies being investigated for use on the ISS and potential commercial utilization activities being examined including proposed design reference missions (DRM's) and the technologies being assessed by the Pre-planned Program Improvement (P(sup 3) I) Working Group. This information is very high level and does not provide the relevant information necessary for detailed design efforts. This document is meant to educate readers on the ISS and to stimulate the generation of ideas for enhancement and utilization of the ISS, either by or for the government, academia, and commercial industry.

The science of exoplanets and their systems.

PubMed

Lammer, Helmut; Blanc, Michel; Benz, Willy; Fridlund, Malcolm; Foresto, Vincent Coudé du; Güdel, Manuel; Rauer, Heike; Udry, Stephane; Bonnet, Roger-Maurice; Falanga, Maurizio; Charbonneau, David; Helled, Ravit; Kley, Willy; Linsky, Jeffrey; Elkins-Tanton, Linda T; Alibert, Yann; Chassefière, Eric; Encrenaz, Therese; Hatzes, Artie P; Lin, Douglas; Liseau, Rene; Lorenzen, Winfried; Raymond, Sean N

2013-09-01

A scientific forum on "The Future Science of Exoplanets and Their Systems," sponsored by Europlanet and the International Space Science Institute (ISSI) and co-organized by the Center for Space and Habitability (CSH) of the University of Bern, was held during December 5 and 6, 2012, in Bern, Switzerland. It gathered 24 well-known specialists in exoplanetary, Solar System, and stellar science to discuss the future of the fast-expanding field of exoplanetary research, which now has nearly 1000 objects to analyze and compare and will develop even more quickly over the coming years. The forum discussions included a review of current observational knowledge, efforts for exoplanetary atmosphere characterization and their formation, water formation, atmospheric evolution, habitability aspects, and our understanding of how exoplanets interact with their stellar and galactic environment throughout their history. Several important and timely research areas of focus for further research efforts in the field were identified by the forum participants. These scientific topics are related to the origin and formation of water and its delivery to planetary bodies and the role of the disk in relation to planet formation, including constraints from observations as well as star-planet interaction processes and their consequences for atmosphere-magnetosphere environments, evolution, and habitability. The relevance of these research areas is outlined in this report, and possible themes for future ISSI workshops are identified that may be proposed by the international research community over the coming 2-3 years.

The evolution of Earth Observation satellites in Europe and its impact on the performance of emergency response services

NASA Astrophysics Data System (ADS)

Denis, Gil; de Boissezon, Hélène; Hosford, Steven; Pasco, Xavier; Montfort, Bruno; Ranera, Franck

2016-10-01

The paper reviews the evolution of Earth Observation systems in Europe and Worldwide and analyses the potential impact of their performance in support of emergency response services. Earth Observation satellites play already a significant role in supporting the action of first responders in case of major disasters. The main principle is the coordinated use of satellites in order to ensure a rapid response and the timely delivery of images and geospatial information of the area affected by the event. The first part of the paper reviews the main instruments and evaluates their current performance. The International Charter ;Space and Major Disasters;, signed in October 2000, was the first international initiative aimed at establishing a unified system for the acquisition of space data. The charter is a cooperation agreement between space agencies and operators of space systems. At regional level, a similar instrument exists in Asia: Sentinel-Asia. In the frame of the European programme Copernicus, the emergency management service was launched in 2009. Geo-information products derived from space imagery are delivered during all phases of the emergency management cycle, in either rush or non-rush mode, free of charge for the users. In both cases, the capacities were historically drawn from national missions, funded with public money and directly operated by the space agencies or by national operators.

Feedback coupling in dynamical systems

NASA Astrophysics Data System (ADS)

Trimper, Steffen; Zabrocki, Knud

2003-05-01

Different evolution models are considered with feedback-couplings. In particular, we study the Lotka-Volterra system under the influence of a cumulative term, the Ginzburg-Landau model with a convolution memory term and chemical rate equations with time delay. The memory leads to a modified dynamical behavior. In case of a positive coupling the generalized Lotka-Volterra system exhibits a maximum gain achieved after a finite time, but the population will die out in the long time limit. In the opposite case, the time evolution is terminated in a crash. Due to the nonlinear feedback coupling the two branches of a bistable model are controlled by the the strength and the sign of the memory. For a negative coupling the system is able to switch over between both branches of the stationary solution. The dynamics of the system is further controlled by the initial condition. The diffusion-limited reaction is likewise studied in case the reacting entities are not available simultaneously. Whereas for an external feedback the dynamics is altered, but the stationary solution remain unchanged, a self-organized internal feedback leads to a time persistent solution.

The emphasis given to evolution in state science standards: A lever for change in evolution education?

NASA Astrophysics Data System (ADS)

Skoog, Gerald; Bilica, Kimberly

2002-07-01

This study analyzed the science frameworks of 49 states and the District of Colombia to determine the emphasis given to evolution in these documents at the middle and secondary levels. These concepts were species evolve over time, speciation, diversity of life, descent with modification from common ancestry, evidence of evolution, natural selection, pace and direction of evolution, and human evolution. Collectively, the 50 science frameworks emphasized evolution in a manner that suggests that if the public's support for standards-based curricula is a reality, the study of evolution will be emphasized in an unprecedented manner in the nation's schools in the near future. However, all concepts were not emphasized equally in these documents. For example, human evolution was included in only seven documents. The word evolution is absent from some standards. Despite these negatives, recent actions to improve existing standards or to adopt new standards that emphasize evolution have occurred. The metaphor lever of change is often used in the context of school reform. This metaphor suggests a simple system where one change can result in a desired outcome. However, in classrooms where curriculum decisions evolve constantly, multiple factors interact and reinforce one another in response to both internal and external contingencies that emerge. Educational change can not be reduced to a simple linear cause/effect situation. The change process involved is nonlinear where what goes in is not proportional to what comes out because of feedback loops and other factors that complicate results. This nonlinearity is reflected in the varied responses of teachers to specific contingencies. Yet, systems can be changed and nudged towards a structure where desired outcomes will emerge. Judicial rulings indicating that the teaching of evolution cannot be prohibited or equal time for creationism mandated, improved coverage of evolution in secondary school biology textbooks, the negative response of many leaders, scientists, organizations, and editorial writers to the 1999 decision of the Kansas State Board of Education to deemphasize and misrepresent evolution in the state's science standards, and the emphasis given to evolution in the standards reviewed for this study, all coalesce to provide needed support for administrators and teachers who are striving to create science curricula that emphasize evolution in a manner commensurate with its importance in understanding the natural world and our place within it.

The evolution of robotic urologic surgery.

PubMed

Nguyen, Mike Minh; Das, Sakti

2004-11-01

The incorporation of robotics into surgical technology is a relatively recent development. Robotic surgical systems can be classified as master-slave systems, precise-path systems, or intern-replacement systems. Master-slave systems, the most familiar type, were developed from initial experiments in "telepresence" surgery funded by the US Department of Defense. Urology has embraced the use of commercial robotic surgical systems in a growing number of clinical applications. Although drawbacks and limitations exist for the use of surgical robotics, the systems are developing rapidly and an expanded role for this technology in the future of urology is inevitable. This article reviews the history of the use of robotics in surgery, focusing on its specific application to urology.

Survival Of Pure Disc Galaxies Over The Last 8 Billion Years

NASA Astrophysics Data System (ADS)

Sachdeva, Sonali

2016-09-01

The presence of pure disk galaxies without any bulge component, i.e., neither classical nor pseudo, poses a severe challenge not just to the hierarchical galaxy formation models but also to the theories of internal secular evolution. We discover that a significant fraction of disk galaxies ( 15-18 %) in the Hubble Deep Field (0.4 < z < 1.0) as well as in the local Universe (0.02 < z < 0.05) are such pure disk systems (PDS). We trace the evolution of this population to find how they survived the merger violence and other disk instabilities to remain dynamically undisturbed. We find that smooth accretion of cold gas via cosmic filaments is the most probable mode of their growth in mass and size since z 1. We speculate that PDSs are dynamically hotter and cushioned in massive dark matter haloes which may prevent them from undergoing strong secular evolution.

Space biology research development

NASA Technical Reports Server (NTRS)

Bonting, Sjoerd L.

1993-01-01

The purpose of the Search for Extraterrestrial Intelligence (SETI) Institute is to conduct and promote research related activities regarding the search for extraterrestrial life, particularly intelligent life. Such research encompasses the broad discipline of 'Life in the Universe', including all scientific and technological aspects of astronomy and the planetary sciences, chemical evolution, the origin of life, biological evolution, and cultural evolution. The primary purpose was to provide funding for the Principal Investigator to collaborate with the personnel of the SETI Institute and the NASA-Ames Research center in order to plan and develop space biology research on and in connection with Space Station Freedom; to promote cooperation with the international partners in the space station; to conduct a study on the use of biosensors in space biology research and life support system operation; and to promote space biology research through the initiation of an annual publication 'Advances in Space Biology and Medicine'.

Evolution and development of brain networks: from Caenorhabditis elegans to Homo sapiens.

PubMed

Kaiser, Marcus; Varier, Sreedevi

2011-01-01

Neural networks show a progressive increase in complexity during the time course of evolution. From diffuse nerve nets in Cnidaria to modular, hierarchical systems in macaque and humans, there is a gradual shift from simple processes involving a limited amount of tasks and modalities to complex functional and behavioral processing integrating different kinds of information from highly specialized tissue. However, studies in a range of species suggest that fundamental similarities, in spatial and topological features as well as in developmental mechanisms for network formation, are retained across evolution. 'Small-world' topology and highly connected regions (hubs) are prevalent across the evolutionary scale, ensuring efficient processing and resilience to internal (e.g. lesions) and external (e.g. environment) changes. Furthermore, in most species, even the establishment of hubs, long-range connections linking distant components, and a modular organization, relies on similar mechanisms. In conclusion, evolutionary divergence leads to greater complexity while following essential developmental constraints.

[Evolution of education in nursing].

PubMed

Clavijo Chamorro, María Zoraida; Romero de Julián, Francisco Javier; Paniagua Vivas, María Sandra

2016-07-26

This study focuses on investigating the evolution of nursing studies in order to know how much this transformation has contributed to the development of the nursing profession. Literature review with data sources from different national and international databases. These sources provide an update on the ongoing evolution of nursing studies and the progress of this profession as a result of change. The competencies and skills that add value to the nursing profession are: an evidence-based practice; empathic communication; and other broad-range skills such as critical thinking. All are necessary in order to develop the profession alongside the constant changes in the health systems and the improvement of quality care. These competencies and skills should be evaluated and their achievement is being reached through the "portfolio". Innovations that enable the development of these skills can be found in education, strategies and tools used by educators and institutions.

Internal Structure of Virtual Communications in Communities of Inquiry in Higher Education: Phases, Evolution and Participants' Satisfaction

ERIC Educational Resources Information Center

Gutierrez-Santiuste, Elba; Gallego-Arrufat, Maria-Jesus

2015-01-01

This study investigates the phases of development of synchronous and asynchronous virtual communication produced in a community of inquiry (CoI) by analyzing the internal structure of each intervention in the forum and each chat session to determine the evolution of their social, cognitive and teaching character. It also analyzes the participating…

Orbital Debris: A Policy Perspective

NASA Technical Reports Server (NTRS)

Johnson, Nicholas L.

2007-01-01

A viewgraph presentation describing orbital debris from a policy perspective is shown. The contents include: 1) Voyage through near-Earth Space-animation; 2) What is Orbital Debris?; 3) Orbital Debris Detectors and Damage Potential; 4) Hubble Space Telescope; 5) Mir Space Station Solar Array; 6) International Space Station; 7) Space Shuttle; 8) Satellite Explosions; 9) Satellite Collisions; 10) NASA Orbital Debris Mitigation Guidelines; 11) International Space Station Jettison Policy; 12) Controlled/Uncontrolled Satellite Reentries; 13) Return of Space Objects; 14) Orbital Debris and U.S. National Space Policy; 15) U.S Government Policy Strategy; 16) Bankruptcy of the Iridium Satellite System; 17) Inter-Agency Space Debris Coordination Committee (IADC); 18) Orbital Debris at the United Nations; 19) Chinese Anti-satellite System; 20) Future Evolution of Satellite Population; and 21) Challenge of Orbital Debris

'Desa SIAGA', the 'Alert Village': the evolution of an iconic brand in Indonesian public health strategies.

PubMed

Hill, Peter S; Goeman, Lieve; Sofiarini, Rahmi; Djara, Maddi M

2014-07-01

In 1999, the Ministry of Women's Empowerment in Indonesia worked with advertisers in Jakarta and international technical advisors to develop the concept of 'Suami SIAGA', the 'Alert Husband', confronting Indonesian males with their responsibilities to be aware of their wives' needs and ensure early access if needed to trained obstetrics care. The model was rapidly expanded to apply to the 'Desa SIAGA', the 'Alert Village', with communities assuming the responsibility for awareness of the risks of pregnancy and childbirth, and supporting registered pregnant mothers with funding and transportation for emergency obstetric assistance, and identified blood donors. Based on the participant observation, interviews and documentary analysis, this article uses a systems perspective to trace the evolution of that iconic 'brand' as new national and international actors further developed the concept and its application in provincial and national programmes. In 2010, it underwent a further transformation to become 'Desa Siaga Aktif', a national programme with responsibilities expanded to include the provision of basic health services at village level, and the surveillance of communicable disease, monitoring of lifestyle activities and disaster preparedness, in addition to the management of obstetric emergencies. By tracking the use of this single 'brand', the study provides insights into the complex adaptive system of policy and programme development with its rich interactions between multiple international, national, provincial and sectoral stakeholders, the unpredictable responses to feedback from these actors and their activities and the resultant emergence of new policy elements, new programmes and new levels of operation within the system. Published by Oxford University Press in association with The London School of Hygiene and Tropical Medicine © The Author 2013; all rights reserved.

Oligo-Miocene thinning of the Beni Bousera peridotites and their Variscan crustal host rocks, Internal Rif, Morocco

NASA Astrophysics Data System (ADS)

Gueydan, Frédéric; Pitra, Pavel; Afiri, Abdelkhaleq; Poujol, Marc; Essaifi, Abderrahim; Paquette, Jean-Louis

2015-06-01

Deciphering Variscan versus Alpine history in the Internal Rif system is a key to constrain the tectonic evolution of the Alboran domain and hence the geodynamics of the western Mediterranean system during the Cenozoic. This study focuses on the evolution of the metamorphic envelope of the Beni Bousera massif and its relation to the underlying peridotites. Combining structural geology, metamorphic petrology, and laser ablation inductively coupled plasma mass spectrometry U-Th-Pb dating of monazite, this study contributes to the understanding of the tectonic history of the western Internal Rif. The regional foliation (S2) is characterized by low pressure-high temperature (LP-HT) mineral assemblages and obliterates a former foliation (S1) developed along a Barrovian (medium pressure-medium temperature, MP-MT) metamorphic gradient. The dating of some metamorphic monazite grains from a micaschist and a migmatitic gneiss demonstrates that the crustal envelope of the peridotite recorded two distinct tectonometamorphic episodes. Data from monazite inclusions in S1 garnet suggest that the first event, D1, is older than 250-170 Ma and likely related to the Variscan collision, in agreement with the Barrovian type of the metamorphic gradient. The second event, D2, is Alpine in age (at circa 21 Ma) and corresponds to a strong lithosphere thinning allowing subsequent subcontinental mantle exhumation. Such a tectonic context provides an explanation for the LP-HT metamorphic gradient that is recorded in the regional foliation of the western Betic-Rif system. This extension is probably related to a subduction slab rollback in the western end of the Mediterranean realm during the Oligo-Miocene times. No evidence for a Tertiary high pressure/low temperature metamorphism has been identified in the studied area.

Mapping forces in a 3D elastic assembly of grains

NASA Astrophysics Data System (ADS)

Saadatfar, Mohammad; Sheppard, Adrian P.; Senden, Tim J.; Kabla, Alexandre J.

2012-01-01

Our understanding of the elasticity and rheology of disordered materials, such as granular piles, foams, emulsions or dense suspensions relies on improving experimental tools to characterise their behaviour at the particle scale. While 2D observations are now routinely carried out in laboratories, 3D measurements remain a challenge. In this paper, we use a simple model system, a packing of soft elastic spheres, to illustrate the capability of X-ray microtomography to characterise the internal structure and local behaviour of granular systems. Image analysis techniques can resolve grain positions, shapes and contact areas; this is used to investigate the material's microstructure and its evolution upon strain. In addition to morphological measurements, we develop a technique to quantify contact forces and estimate the internal stress tensor. As will be illustrated in this paper, this opens the door to a broad array of static and dynamical measurements in 3D disordered systems.

The hidden hyperbolic geometry of international trade: World Trade Atlas 1870-2013.

PubMed

García-Pérez, Guillermo; Boguñá, Marián; Allard, Antoine; Serrano, M Ángeles

2016-09-16

Here, we present the World Trade Atlas 1870-2013, a collection of annual world trade maps in which distance combines economic size and the different dimensions that affect international trade beyond mere geography. Trade distances, based on a gravity model predicting the existence of significant trade channels, are such that the closer countries are in trade space, the greater their chance of becoming connected. The atlas provides us with information regarding the long-term evolution of the international trade system and demonstrates that, in terms of trade, the world is not flat but hyperbolic, as a reflection of its complex architecture. The departure from flatness has been increasing since World War I, meaning that differences in trade distances are growing and trade networks are becoming more hierarchical. Smaller-scale economies are moving away from other countries except for the largest economies; meanwhile those large economies are increasing their chances of becoming connected worldwide. At the same time, Preferential Trade Agreements do not fit in perfectly with natural communities within the trade space and have not necessarily reduced internal trade barriers. We discuss an interpretation in terms of globalization, hierarchization, and localization; three simultaneous forces that shape the international trade system.

The hidden hyperbolic geometry of international trade: World Trade Atlas 1870-2013

NASA Astrophysics Data System (ADS)

García-Pérez, Guillermo; Boguñá, Marián; Allard, Antoine; Serrano, M. Ángeles

2016-09-01

Here, we present the World Trade Atlas 1870-2013, a collection of annual world trade maps in which distance combines economic size and the different dimensions that affect international trade beyond mere geography. Trade distances, based on a gravity model predicting the existence of significant trade channels, are such that the closer countries are in trade space, the greater their chance of becoming connected. The atlas provides us with information regarding the long-term evolution of the international trade system and demonstrates that, in terms of trade, the world is not flat but hyperbolic, as a reflection of its complex architecture. The departure from flatness has been increasing since World War I, meaning that differences in trade distances are growing and trade networks are becoming more hierarchical. Smaller-scale economies are moving away from other countries except for the largest economies; meanwhile those large economies are increasing their chances of becoming connected worldwide. At the same time, Preferential Trade Agreements do not fit in perfectly with natural communities within the trade space and have not necessarily reduced internal trade barriers. We discuss an interpretation in terms of globalization, hierarchization, and localization; three simultaneous forces that shape the international trade system.

Streamlining CASTOR to manage the LHC data torrent

NASA Astrophysics Data System (ADS)

Lo Presti, G.; Espinal Curull, X.; Cano, E.; Fiorini, B.; Ieri, A.; Murray, S.; Ponce, S.; Sindrilaru, E.

2014-06-01

This contribution describes the evolution of the main CERN storage system, CASTOR, as it manages the bulk data stream of the LHC and other CERN experiments, achieving over 90 PB of stored data by the end of LHC Run 1. This evolution was marked by the introduction of policies to optimize the tape sub-system throughput, going towards a cold storage system where data placement is managed by the experiments' production managers. More efficient tape migrations and recalls have been implemented and deployed where bulk meta-data operations greatly reduce the overhead due to small files. A repack facility is now integrated in the system and it has been enhanced in order to automate the repacking of several tens of petabytes, required in 2014 in order to prepare for the next LHC run. Finally the scheduling system has been evolved to integrate the internal monitoring. To efficiently manage the service a solid monitoring infrastructure is required, able to analyze the logs produced by the different components (about 1 kHz of log messages). A new system has been developed and deployed, which uses a transport messaging layer provided by the CERN-IT Agile Infrastructure and exploits technologies including Hadoop and HBase. This enables efficient data mining by making use of MapReduce techniques, and real-time data aggregation and visualization. The outlook for the future is also presented. Directions and possible evolution will be discussed in view of the restart of data taking activities.

Cellular automaton model for molecular traffic jams

NASA Astrophysics Data System (ADS)

Belitsky, V.; Schütz, G. M.

2011-07-01

We consider the time evolution of an exactly solvable cellular automaton with random initial conditions both in the large-scale hydrodynamic limit and on the microscopic level. This model is a version of the totally asymmetric simple exclusion process with sublattice parallel update and thus may serve as a model for studying traffic jams in systems of self-driven particles. We study the emergence of shocks from the microscopic dynamics of the model. In particular, we introduce shock measures whose time evolution we can compute explicitly, both in the thermodynamic limit and for open boundaries where a boundary-induced phase transition driven by the motion of a shock occurs. The motion of the shock, which results from the collective dynamics of the exclusion particles, is a random walk with an internal degree of freedom that determines the jump direction. This type of hopping dynamics is reminiscent of some transport phenomena in biological systems.

The gallium melting-point standard: its role in our temperature measurement system.

PubMed

Mangum, B W

1977-01-01

The latest internationally-adopted temperature scale, the International Practical Temperature Scale of 1968 (amended edition of 1975), is discussed in some detail and a brief description is given of its evolution. The melting point of high-purity gallium (stated to be at least 99.99999% pure) as a secondary temperature reference point is evaluated. I believe that this melting-point temperature of gallium should be adopted by the various medical professional societies and voluntary standards groups as the reaction temperature for enzyme reference methods in clinical enzymology. Gallium melting-point cells are available at the National Bureau of Standards as Standard Reference Material No. 1968.

A hypothesis on the biological origins and social evolution of music and dance

PubMed Central

Wang, Tianyan

2015-01-01

The origins of music and musical emotions is still an enigma, here I propose a comprehensive hypothesis on the origins and evolution of music, dance, and speech from a biological and sociological perspective. I suggest that every pitch interval between neighboring notes in music represents corresponding movement pattern through interpreting the Doppler effect of sound, which not only provides a possible explanation for the transposition invariance of music, but also integrates music and dance into a common form—rhythmic movements. Accordingly, investigating the origins of music poses the question: why do humans appreciate rhythmic movements? I suggest that human appreciation of rhythmic movements and rhythmic events developed from the natural selection of organisms adapting to the internal and external rhythmic environments. The perception and production of, as well as synchronization with external and internal rhythms are so vital for an organism's survival and reproduction, that animals have a rhythm-related reward and emotion (RRRE) system. The RRRE system enables the appreciation of rhythmic movements and events, and is integral to the origination of music, dance and speech. The first type of rewards and emotions (rhythm-related rewards and emotions, RRREs) are evoked by music and dance, and have biological and social functions, which in turn, promote the evolution of music, dance and speech. These functions also evoke a second type of rewards and emotions, which I name society-related rewards and emotions (SRREs). The neural circuits of RRREs and SRREs develop in species formation and personal growth, with congenital and acquired characteristics, respectively, namely music is the combination of nature and culture. This hypothesis provides probable selection pressures and outlines the evolution of music, dance, and speech. The links between the Doppler effect and the RRREs and SRREs can be empirically tested, making the current hypothesis scientifically concrete. PMID:25741232

Integrated Analysis of Piezoelectric Resonators as Components of Electronic Systems

DTIC Science & Technology

2015-09-07

Transient thickness-shear vibration of apiezoelectric plate of monoclinic crystals, International Journal of Applied Electromagnetics and Mechanics 38...52, 1461-1467 (2005)., (04 2012): 811. doi: N Liu, J S Yang, F Jin. Transient thickness-shear vibration of a piezoelectric plate of monoclinic...2012) 27–37, (02 2012): 27. doi: Zhi Wang, Minghao Zhao, Jiashi Yang. Amplitude evolution equation and transient effects in piezoelectric crystal

The PBS Triangle: Does It Fit as a Heuristic? A Reflection on the First International Conference on Positive Behavior Support

ERIC Educational Resources Information Center

Baker, Candace Kay

2005-01-01

In this article, the author explores the evolution of the use of the triangle as a communication tool for describing positive behavior support (PBS) systems. The conceptual framework for the triangle used for PBS is credited to Walker et al. In that seminal work, the a model of school-based prevention strategies for children displaying antisocial…

A Data Specification for Software Project Performance Measures: Results of a Collaboration on Performance Measurement

DTIC Science & Technology

2008-07-01

cycle Evolution of a system, product, service, project or other human-made entity from conception through retirement [ ISO 12207 ]. Logical line of...012 [ ISO 1995] International Organization for Standardization. ISO /IEC 12207 :1995—Information technology— Software life cycle processes. http...definitions, authors were asked to use or align with already existing standards such as those available through ISO and IEEE when possible. Literature

High-temperature morphological evolution of lithographically introduced cavities in silicon carbide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Narushima, Takayuki; Glaeser, Andreas M.

2000-12-01

Internal cavities of controlled geometry and crystallography were introduced in 6H silicon carbide single crystals by combining lithographic methods, ion beam etching, and solid-state diffusion bonding. The morphological evolution of these internal cavities (negative crystals) in response to anneals of up to 128 h duration at 1900 degrees C was examined using optical microscopy. Surface energy anisotropy and faceting have a strong influence on both the geometric and kinetic characteristics of evolution. Decomposition of 12{bar 1}0 cavity edges into 101{bar 0} facets was observed after 16 h anneals, indicating that 12{bar 1}0 faces are not components of the Wulff shape.more » The shape evolution kinetics of penny-shaped cavities were also investigated. Experimentally observed evolution rates decreased much more rapidly with those predicted by a model in which surface diffusion is assumed to be rate-limiting. This suggests that the development of facets, and the associated loss of ledges and terraces during the initial stages of evolution results in an evolution process limited by the nucleation rate of attachment/detachment sites (ledges) on the facets.« less

A Cenozoic tectonic model for Southeast Asia - microplates and basins

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maher, K.A.

1995-04-01

A computer-assisted Cenozoic tectonic model was built for Southeast Asia and used to construct 23 base maps, 2 to 6 million years apart. This close temporal spacing was necessary to constrain all the local geometric shifts in a consistent and geologically feasible fashion. More than a hundred individual blocks were required to adequately treat Cenozoic microplate processes at a basic level. The reconstructions show tectonic evolution to be characterized by long periods of gradual evolution, interrupted by brief, widespread episodes of reorganization in fundamental plate geometries and kinematics. These episodes are triggered by major collisions, or by accumulation of smallermore » changes. The model takes into account difficulties inherent in the region. The Pacific and Indo-Australian plates and their predecessors have driven westward and northward since the late Paleozoic, towards each other and the relatively stationary backstop of Asia. Southeast Asia is therefore the result of a long-lived, complex process of convergent tectonics, making it difficult to reconstruct tectonic evolution as much of the continental margin and sea floor spreading record was erased. In addition, the region has been dominated by small-scale microplate processes with short time scales and internal deformation, taking place in rapidly evolving and more ductile buffer zones between the major rigid plate systems. These plate interaction zones have taken up much of the relative motion between the major plates. Relatively ephemeral crustal blocks appear and die within the buffer zones, or accrete to and disperse from the margins of the major plate systems. However, such microplate evolution is the dominant factor in Cenozoic basin evolution. This detailed testonic model aids in comprehension and prediction of basin development, regional hydrocarbon habitat, and petroleum systems.« less

Biopharmaceutical Innovation System in China: System Evolution and Policy Transitions (Pre-1990s-2010s)

PubMed Central

Hu, Hao; Chung, Chao-Chen

2015-01-01

Background: This article sets up the initial discussion of the evolution of biopharmaceutical innovation in China through the perspective of sectoral innovation system (SIS). Methods: Two data sources including archival documentary data and field interviews were used in this study. Archival documentary data was collected from China Food and Drug Administration (CFDA) and Chinese National Knowledge Infrastructure (CNKI). In addition, industrial practitioners and leading researchers in academia were interviewed. Results: Biopharmaceutical in China was established through international knowledge transfer. The firms played more active role in commercializing biopharmaceutical in China though universities and research institutes were starting to interact with local firms and make contribution to biopharmaceutical industrialization. The transition of the Chinese government’s policies continuously shapes the evolution of biopharmaceutical sector. Policies have been dramatic changes before and after 1980s to encourage developing biopharmaceutical as a competitive industry for China. Conclusion: A SIS for biopharmaceutical has been shaped in China. However, currently biopharmaceutical is still a small sector in China, and for the further growth of the industry more synthetic policies should be implemented. Not only the policy supports towards the research and innovation of biopharmaceuticals in the early stage of development should be attended, but also commercialization of biopharmaceutical products in the later stage of sales. PMID:26673466

Biopharmaceutical Innovation System in China: System Evolution and Policy Transitions (Pre-1990s-2010s).

PubMed

Hu, Hao; Chung, Chao-Chen

2015-09-03

This article sets up the initial discussion of the evolution of biopharmaceutical innovation in China through the perspective of sectoral innovation system (SIS). Two data sources including archival documentary data and field interviews were used in this study. Archival documentary data was collected from China Food and Drug Administration (CFDA) and Chinese National Knowledge Infrastructure (CNKI). In addition, industrial practitioners and leading researchers in academia were interviewed. Biopharmaceutical in China was established through international knowledge transfer. The firms played more active role in commercializing biopharmaceutical in China though universities and research institutes were starting to interact with local firms and make contribution to biopharmaceutical industrialization. The transition of the Chinese government's policies continuously shapes the evolution of biopharmaceutical sector. Policies have been dramatic changes before and after 1980s to encourage developing biopharmaceutical as a competitive industry for China. A SIS for biopharmaceutical has been shaped in China. However, currently biopharmaceutical is still a small sector in China, and for the further growth of the industry more synthetic policies should be implemented. Not only the policy supports towards the research and innovation of biopharmaceuticals in the early stage of development should be attended, but also commercialization of biopharmaceutical products in the later stage of sales. © 2015 by Kerman University of Medical Sciences.

Endocrine interactions between plants and animals: Implications of exogenous hormone sources for the evolution of hormone signaling.

PubMed

Miller, Ashley E M; Heyland, Andreas

2010-05-01

Hormones are central to animal physiology, metabolism and development. Details on signal transduction systems and regulation of hormone synthesis, activation and release have only been studied for a small number of animal groups, notably arthropods and chordates. However, a significant body of literature suggests that hormonal signaling systems are not restricted to these phyla. For example, work on several echinoderm species shows that exogenous thyroid hormones (THs) affect larval development and metamorphosis and our new data provide strong evidence for endogenous synthesis of THs in sea urchin larvae. In addition to these endogenous sources, these larvae obtain THs when they consume phytoplankton. Another example of an exogenously acquired hormone or their precursors is in insect and arthropod signaling. Sterols from plants are essential for the synthesis of ecdysteroids, a crucial group of insect morphogenic steroids. The availability of a hormone or hormone precursor from food has implications for understanding hormone function and the evolution of hormonal signaling in animals. For hormone function, it creates an important link between the environment and the regulation of internal homeostatic systems. For the evolution of hormonal signaling it helps us to better understand how complex endocrine mechanisms may have evolved. Copyright 2009 Elsevier Inc. All rights reserved.

Computer applications in the search for unrelated stem cell donors.

PubMed

Müller, Carlheinz R

2002-08-01

The majority of patients which are eligible for a blood stem cell transplantation from an allogeneic donor do not have a suitable related donor so that an efficient unrelated donor search is a prerequisite for this treatment. Currently, there are over 7 million volunteer donors in the files of 50 registries in the world and in most countries the majority of transplants are performed from a foreign donor. Evidently, computer and communication technology must play a crucial role in the complex donor search process on the national and international level. This article describes the structural elements of the donor search process and discusses major systematic and technical issues to be addressed in the development and evolution of the supporting telematic systems. The theoretical considerations are complemented by a concise overview over the current state of the art which is given by describing the scope, relevance, interconnection and technical background of three major national and international computer appliances: The German Marrow Donor Information System (GERMIS) and the European Marrow Donor Information System (EMDIS) are interoperable business-to-business e-commerce systems and Bone Marrow Donors World Wide (BMDW) is the basic international donor information desk on the web.

Time rescaling and pattern formation in biological evolution.

PubMed

Igamberdiev, Abir U

2014-09-01

Biological evolution is analyzed as a process of continuous measurement in which biosystems interpret themselves in the environment resulting in changes of both. This leads to rescaling of internal time (heterochrony) followed by spatial reconstructions of morphology (heterotopy). The logical precondition of evolution is the incompleteness of biosystem's internal description, while the physical precondition is the uncertainty of quantum measurement. The process of evolution is based on perpetual changes in interpretation of information in the changing world. In this interpretation the external biospheric gradients are used for establishment of new features of organization. It is concluded that biological evolution involves the anticipatory epigenetic changes in the interpretation of genetic symbolism which cannot generally be forecasted but can provide canalization of structural transformations defined by the existing organization and leading to predictable patterns of form generation. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Data Assimilation as a Tool for Developing a Mars International Reference Atmosphere

NASA Technical Reports Server (NTRS)

Houben, Howard

2005-01-01

A new paradigm for a Mars International Reference Atmosphere is proposed. In general, as is certainly now the case for Mars, there are sufficient observational data to specify what the full atmospheric state was under a variety of circumstances (season, dustiness, etc.). There are also general circulation models capable of deter- mining the evolution of these states. If these capabilities are combined-using data assimilation techniques-the resulting analyzed states can be probed to answer a wide variety of questions, whether posed by scientists, mission planners, or others. This system would fulfill all the purposes of an international reference atmosphere and would make the scientific results of exploration missions readily available to the community. Preliminary work on a website that would incorporate this functionality has begun.

Teaching and Learning Evolution: Testing the Principles of a Constructivist Approach through Action Research

ERIC Educational Resources Information Center

Oliver, Mary

2011-01-01

A tenth grade class in an international school studied evolution for four weeks as part of the study of Biology. A diagnostic test was used to determine the main misconceptions students have as they come to the study of evolution. This was followed by a series of explorations of different conceptual models to account for evolution, structured…

Comparative experimental study of gas evolution and gas consumption reactions in sealed Ni-Cd and Ni-MH cells

NASA Astrophysics Data System (ADS)

Cha, Chuansin; Yu, Jingxian; Zhang, Jixiao

The behavior of the sealed Ni-Cd and Ni-MH systems are compared experimentally with regard to their ability to consume gaseous products generated during the overcharge stage of these systems. It was found that the Ni-Cd system could only consume oxygen, while the Ni-MH system possesses the additional ability to adsorb hydrogen and to catalyze the recombination reaction of hydrogen and oxygen. The internal pressure within both sealed Ni-Cd cells and sealed Ni-MH cells can be kept well under control during the charge/overcharge processes if the rate of overcharge is not too high and if there is sufficient surplus of charging capacity at the negative electrodes. However, the internal pressure can rise to dangerously high levels if the rate of overcharge is too high or there is a deficiency of the charging capacity at the negative electrodes. The various factors that may affect the surplus of charging capacity of the negative electrodes are also discussed.

Modelling non-equilibrium thermodynamic systems from the speed-gradient principle.

PubMed

Khantuleva, Tatiana A; Shalymov, Dmitry S

2017-03-06

The application of the speed-gradient (SG) principle to the non-equilibrium distribution systems far away from thermodynamic equilibrium is investigated. The options for applying the SG principle to describe the non-equilibrium transport processes in real-world environments are discussed. Investigation of a non-equilibrium system's evolution at different scale levels via the SG principle allows for a fresh look at the thermodynamics problems associated with the behaviour of the system entropy. Generalized dynamic equations for finite and infinite number of constraints are proposed. It is shown that the stationary solution to the equations, resulting from the SG principle, entirely coincides with the locally equilibrium distribution function obtained by Zubarev. A new approach to describe time evolution of systems far from equilibrium is proposed based on application of the SG principle at the intermediate scale level of the system's internal structure. The problem of the high-rate shear flow of viscous fluid near the rigid plane plate is discussed. It is shown that the SG principle allows closed mathematical models of non-equilibrium processes to be constructed.This article is part of the themed issue 'Horizons of cybernetical physics'. © 2017 The Author(s).

Modelling non-equilibrium thermodynamic systems from the speed-gradient principle

NASA Astrophysics Data System (ADS)

Khantuleva, Tatiana A.; Shalymov, Dmitry S.

2017-03-01

The application of the speed-gradient (SG) principle to the non-equilibrium distribution systems far away from thermodynamic equilibrium is investigated. The options for applying the SG principle to describe the non-equilibrium transport processes in real-world environments are discussed. Investigation of a non-equilibrium system's evolution at different scale levels via the SG principle allows for a fresh look at the thermodynamics problems associated with the behaviour of the system entropy. Generalized dynamic equations for finite and infinite number of constraints are proposed. It is shown that the stationary solution to the equations, resulting from the SG principle, entirely coincides with the locally equilibrium distribution function obtained by Zubarev. A new approach to describe time evolution of systems far from equilibrium is proposed based on application of the SG principle at the intermediate scale level of the system's internal structure. The problem of the high-rate shear flow of viscous fluid near the rigid plane plate is discussed. It is shown that the SG principle allows closed mathematical models of non-equilibrium processes to be constructed. This article is part of the themed issue 'Horizons of cybernetical physics'.

Modelling non-equilibrium thermodynamic systems from the speed-gradient principle

PubMed Central

Khantuleva, Tatiana A.

2017-01-01

The application of the speed-gradient (SG) principle to the non-equilibrium distribution systems far away from thermodynamic equilibrium is investigated. The options for applying the SG principle to describe the non-equilibrium transport processes in real-world environments are discussed. Investigation of a non-equilibrium system's evolution at different scale levels via the SG principle allows for a fresh look at the thermodynamics problems associated with the behaviour of the system entropy. Generalized dynamic equations for finite and infinite number of constraints are proposed. It is shown that the stationary solution to the equations, resulting from the SG principle, entirely coincides with the locally equilibrium distribution function obtained by Zubarev. A new approach to describe time evolution of systems far from equilibrium is proposed based on application of the SG principle at the intermediate scale level of the system's internal structure. The problem of the high-rate shear flow of viscous fluid near the rigid plane plate is discussed. It is shown that the SG principle allows closed mathematical models of non-equilibrium processes to be constructed. This article is part of the themed issue ‘Horizons of cybernetical physics’. PMID:28115617

On the coupled evolution of oceanic internal waves and quasi-geostrophic flow

NASA Astrophysics Data System (ADS)

Wagner, Gregory LeClaire

Oceanic motion outside thin boundary layers is primarily a mixture of quasi-geostrophic flow and internal waves with either near-inertial frequencies or the frequency of the semidiurnal lunar tide. This dissertation seeks a deeper understanding of waves and flow through reduced models that isolate their nonlinear and coupled evolution from the Boussinesq equations. Three physical-space models are developed: an equation that describes quasi-geostrophic evolution in an arbitrary and prescribed field of hydrostatic internal waves; a three-component model that couples quasi-geostrophic flow to both near-inertial waves and the near-inertial second harmonic; and a model for the slow evolution of hydrostatic internal tides in quasi-geostrophic flow of near-arbitrary scale. This slow internal tide equation opens the path to a coupled model for the energetic interaction of quasi-geostrophic flow and oceanic internal tides. Four results emerge. First, the wave-averaged quasi-geostrophic equation reveals that finite-amplitude waves give rise to a mean flow that advects quasi-geostrophic potential vorticity. Second is the definition of a new material invariant: Available Potential Vorticity, or APV. APV isolates the part of Ertel potential vorticity available for balanced-flow evolution in Eulerian frames and proves necessary in the separating waves and quasi-geostrophic flow. The third result, hashed out for near-inertial waves and quasi-geostrophic flow, is that wave-flow interaction leads to energy exchange even under conditions of weak nonlinearity. For storm-forced oceanic near-inertial waves the interaction often energizes waves at the expense of flow. We call this extraction of balanced quasi-geostrophic energy 'stimulated generation' since it requires externally-forced rather than spontaneously-generated waves. The fourth result is that quasi-geostrophic flow can encourage or 'catalyze' a nonlinear interaction between a near-inertial wave field and its second harmonic that transfers energy to the small near-inertial vertical scales of wave breaking and mixing.

Beyond Rio? The Evolution of International Environmental Law.

ERIC Educational Resources Information Center

Brunnee, Jutta

1993-01-01

Discusses the expansion and innovation in the use of international environmental law mechanisms to address the problems of global environmental protection. Presents initiatives involving customary international law, forms of international agreements, nonbinding "soft law," and an example involving Canada's biodiversity commitments. (MDH)

Contributions of experimental protobiogenesis to the theory of evolution

NASA Technical Reports Server (NTRS)

Fox, S. W.

1976-01-01

Inferences from experiments in protobiogenesis are examined as a forward extension of the theory of evolutionary biology. A nondiscontinuous, intraconsistent theory of general evolution embracing both protobiology and biology is outlined. This overview emphasizes Darwinian selection in the later stages of evolution, and stereochemical molecular selection in some of its earlier stages. It incorporates the concept of limitation of the scope of evolution by internal constraints on variation, based on the argument that internally limiting constraints observed in experiments with molecules are operative in organisms, if chemical processes occur within biological processes and biological processes are assumed to be exponentializations of chemical processes. Major evolutionary events might have occurred by rapid self-assembly processes analogous to those observed in the formation of phase-separated microspheres from amorphous powder or supersaturated solutions.

Prebiotic replicase evolution in a surface-bound metabolic system: parasites as a source of adaptive evolution

PubMed Central

2008-01-01

Background The remarkable potential of recent forms of life for reliably passing on genetic information through many generations now depends on the coordinated action of thousands of specialized biochemical "machines" (enzymes) that were obviously absent in prebiotic times. Thus the question how a complicated system like the living cell could have assembled on Earth seems puzzling. In seeking for a scientific explanation one has to search for step-by-step evolutionary changes from prebiotic chemistry to the emergence of the first proto-cell. Results We try to sketch a plausible scenario for the first steps of prebiotic evolution by exploring the ecological feasibility of a mineral surface-bound replicator system that facilitates a primitive metabolism. Metabolism is a hypothetical network of simple chemical reactions producing monomers for the template-copying of RNA-like replicators, which in turn catalyse metabolic reactions. Using stochastic cellular automata (SCA) simulations we show that the surface-bound metabolic replicator system is viable despite internal competition among the genes and that it also maintains a set of mild "parasitic" sequences which occasionally evolve functions such as that of a replicase. Conclusion Replicase activity is shown to increase even at the expense of slowing down the replication of the evolving ribozyme itself, due to indirect mutualistic benefits in a diffuse form of group selection among neighbouring replicators. We suggest possible paths for further evolutionary changes in the metabolic replicator system leading to increased metabolic efficiency, improved replicase functionality, and membrane production. PMID:18826645

The influence of international and domestic events in the evolution of forest inventory and reporting consistency in the United States

Treesearch

W. Brad Smith

2009-01-01

This article takes a brief chronological look at resource inventory and reporting and links to international influences. It explores events as drivers of more consistent data within the United States and highlights key dates and events in the evolution of inventory policy and practice. From King George to L?Ecole nationale forestiere to the Food and Agriculture...

The Strata-1 Regolith Dynamics Experiment: Class 1E Science on ISS

NASA Technical Reports Server (NTRS)

Fries, Marc; Graham, Lee; John, Kristen

2016-01-01

The Strata-1 experiment studies the evolution of small body regolith through long-duration exposure of simulant materials to the microgravity environment on the International Space Station (ISS). This study will record segregation and mechanical dynamics of regolith simulants in a microgravity and vibration environment similar to that experienced by regolith on small Solar System bodies. Strata-1 will help us understand regolith dynamics and will inform design and procedures for landing and setting anchors, safely sampling and moving material on asteroidal surfaces, processing large volumes of material for in situ resource utilization (ISRU) purposes, and, in general, predicting the behavior of large and small particles on disturbed asteroid surfaces. This experiment is providing new insights into small body surface evolution.

Space exploration and colonization - Towards a space faring society

NASA Technical Reports Server (NTRS)

Hammond, Walter E.

1990-01-01

Development trends of space exploration and colonization since 1957 are reviewed, and a five-phase evolutionary program planned for the long-term future is described. The International Geosphere-Biosphere program which is intended to provide the database on enviromental changes of the earth as a global system is considered. Evolution encompasses the anticipated advantages of such NASA observation projects as the Hubble Space Telescope, the Gamma Ray Observatory, the Advanced X-Ray Astrophysics Facility, and the Cosmic Background Explorer. Attention is given to requirements for space colonization, including development of artificial gravity and countermeasures to mitigate zero gravity problems; robotics and systems aimed to minimize human exposure to the space environment; the use of nuclear propulsion; and international collaboration on lunar-Mars projects. It is recommended that nuclear energy sources be developed for both propulsion and as extraterrestrial power plants.

New Comprehensive Cytogenetic Scoring System for Primary Myelodysplastic Syndromes (MDS) and Oligoblastic Acute Myeloid Leukemia After MDS Derived From an International Database Merge

PubMed Central

Schanz, Julie; Tüchler, Heinz; Solé, Francesc; Mallo, Mar; Luño, Elisa; Cervera, José; Granada, Isabel; Hildebrandt, Barbara; Slovak, Marilyn L.; Ohyashiki, Kazuma; Steidl, Christian; Fonatsch, Christa; Pfeilstöcker, Michael; Nösslinger, Thomas; Valent, Peter; Giagounidis, Aristoteles; Aul, Carlo; Lübbert, Michael; Stauder, Reinhard; Krieger, Otto; Garcia-Manero, Guillermo; Faderl, Stefan; Pierce, Sherry; Le Beau, Michelle M.; Bennett, John M.; Greenberg, Peter; Germing, Ulrich; Haase, Detlef

2012-01-01

Purpose The karyotype is a strong independent prognostic factor in myelodysplastic syndromes (MDS). Since the implementation of the International Prognostic Scoring System (IPSS) in 1997, knowledge concerning the prognostic impact of abnormalities has increased substantially. The present study proposes a new and comprehensive cytogenetic scoring system based on an international data collection of 2,902 patients. Patients and Methods Patients were included from the German-Austrian MDS Study Group (n = 1,193), the International MDS Risk Analysis Workshop (n = 816), the Spanish Hematological Cytogenetics Working Group (n = 849), and the International Working Group on MDS Cytogenetics (n = 44) databases. Patients with primary MDS and oligoblastic acute myeloid leukemia (AML) after MDS treated with supportive care only were evaluated for overall survival (OS) and AML evolution. Internal validation by bootstrap analysis and external validation in an independent patient cohort were performed to confirm the results. Results In total, 19 cytogenetic categories were defined, providing clear prognostic classification in 91% of all patients. The abnormalities were classified into five prognostic subgroups (P < .001): very good (median OS, 61 months; hazard ratio [HR], 0.5; n = 81); good (49 months; HR, 1.0 [reference category]; n = 1,809); intermediate (26 months; HR, 1.6; n = 529); poor (16 months; HR, 2.6; n = 148); and very poor (6 months; HR, 4.2; n = 187). The internal and external validations confirmed the results of the score. Conclusion In conclusion, these data should contribute to the ongoing efforts to update the IPSS by refining the cytogenetic risk categories. PMID:22331955

Dynamic computer model for the metallogenesis and tectonics of the Circum-North Pacific

USGS Publications Warehouse

Scotese, Christopher R.; Nokleberg, Warren J.; Monger, James W.H.; Norton, Ian O.; Parfenov, Leonid M.; Khanchuk, Alexander I.; Bundtzen, Thomas K.; Dawson, Kenneth M.; Eremin, Roman A.; Frolov, Yuri F.; Fujita, Kazuya; Goryachev, Nikolai A.; Pozdeev, Anany I.; Ratkin, Vladimir V.; Rodinov, Sergey M.; Rozenblum, Ilya S.; Scholl, David W.; Shpikerman, Vladimir I.; Sidorov, Anatoly A.; Stone, David B.

2001-01-01

The digital files on this report consist of a dynamic computer model of the metallogenesis and tectonics of the Circum-North Pacific, and background articles, figures, and maps. The tectonic part of the dynamic computer model is derived from a major analysis of the tectonic evolution of the Circum-North Pacific which is also contained in directory tectevol. The dynamic computer model and associated materials on this CD-ROM are part of a project on the major mineral deposits, metallogenesis, and tectonics of the Russian Far East, Alaska, and the Canadian Cordillera. The project provides critical information on bedrock geology and geophysics, tectonics, major metalliferous mineral resources, metallogenic patterns, and crustal origin and evolution of mineralizing systems for this region. The major scientific goals and benefits of the project are to: (1) provide a comprehensive international data base on the mineral resources of the region that is the first, extensive knowledge available in English; (2) provide major new interpretations of the origin and crustal evolution of mineralizing systems and their host rocks, thereby enabling enhanced, broad-scale tectonic reconstructions and interpretations; and (3) promote trade and scientific and technical exchanges between North America and Eastern Asia.

Climate change influence on the internal structure of talus slopes in the Arctic - A case study from the southern Spitsbergen, Norway

NASA Astrophysics Data System (ADS)

Senderak, K.; Kondracka, M.; Gądek, B.

2017-12-01

Talus slopes are present in all geographical altitudes, but the most active and dynamic slopes occur in high-mountain and polar areas. Spitsbergen, Norwegian archipelago in the Arctic, combines these two environments, therefore, the talus slopes develop in specific environmental conditions that have changed since the beginning of deglaciation. On Spitsbergen, which is 60% glaciated, talus slope evolution depends frequently on the interaction with glaciers, as well as the size of sediment supply area, the lithology, and the intensive of rock weathering. The warming of climate in the Arctic cause the identifiable changes in the internal structures of talus slopes associated with i.e. the melting of glaciers and the high activity of many morphogenetic processes on slope surface. The identification of these changes is a key to understanding of climate change influence (direct and indirect influence) on talus slope evolution. Our work presents the results of research, mainly based on the measurements using electrical resistivity tomography method (ERT) and ground-penetrating radar method (GPR), which were made on the talus slopes of southern Spitsbergen in the vicinity of Polish Polar Station in Hornsund. The geophysical surveys and geomorphological observations show that the climatic factor plays the significant role in the development of slopes, what is clearly visible when analyzing the whole slope systems in the selected glacial valleys (partly glaciated). The differences in the internal structure can depend on distance from the glacier and age of form. This mainly concerns the volume of buried glacial ice in slope material, the thickness of talus slopes, the depth of permafrost and active layer, the stored sedimentological structures including e.g. the traces of fresh material supply. New data on the internal structure of talus slopes developing in the present glaciated area allow for discussions on the talus slope evolution, which, according to the authors, needs to be detailed.

Measurement of turbulence decorrelation during transport barrier evolution in a high-temperature fusion plasma.

PubMed

Nazikian, R; Shinohara, K; Kramer, G J; Valeo, E; Hill, K; Hahm, T S; Rewoldt, G; Ide, S; Koide, Y; Oyama, Y; Shirai, H; Tang, W

2005-04-08

A low power polychromatic beam of microwaves is used to diagnose the behavior of turbulent fluctuations in the core of the JT-60U tokamak during the evolution of the internal transport barrier. A continuous reduction in the size of turbulent structures is observed concomitant with the reduction of the density scale length during the evolution of the internal transport barrier. The density correlation length decreases to the order of the ion gyroradius, in contrast with the much longer scale lengths observed earlier in the discharge, while the density fluctuation level remain similar to the level before transport barrier formation.

Sustaining a Moored Ocean Observing System in the Tropical Pacific: The Evolution of the TAO Array

NASA Astrophysics Data System (ADS)

Grissom, K.; Kessler, W. S.; McArthur, S.

2016-12-01

The Tropical Atmosphere Ocean (TAO) array has been a major observational component of El Niño Southern Oscillation (ENSO) research and operational climate forecasting since its conception in 1984. Developed by NOAA's Pacific Marine Environmental Laboratory (PMEL) in response to the poorly-observed 1982-1983 El Niño, the moored buoy array was completed in 1994 and transitioned from PMEL to NOAA's National Data Buoy Center (NDBC) in 2005. During this transition, the TAO Refresh project was initiated to address equipment obsolescence and the need for more real-time data. Completed in 2011, the "TAO Refresh" array has new capabilities and added value. Then in 2012, federal resource shortfalls threatened the future sustainability of this array. The resulting limited maintenance caused a decline in real-time data, yet it also served as the impetus to focus international attention on the demands of sustaining an observing system capable of monitoring the tropical ocean-atmosphere interaction. To continue collecting observations at historical levels, NOAA and partners needed an alternate strategy, and to this end conceived the international TPOS 2020 project, the Tropical Pacific Observing System for 2020. At more than 30 years, the TAO array stands as one of the longest sustained in-situ ocean observing networks in the world and provides a rare long-term record of a dominant climate signal. Here we review the evolution of the TAO array, from its development at PMEL, to its transition and modernization at NDBC, and provide a preview of its future as a key element of the Tropical Pacific Observing System.

Fractional representation theory - Robustness results with applications to finite dimensional control of a class of linear distributed systems

NASA Technical Reports Server (NTRS)

Nett, C. N.; Jacobson, C. A.; Balas, M. J.

1983-01-01

This paper reviews and extends the fractional representation theory. In particular, new and powerful robustness results are presented. This new theory is utilized to develop a preliminary design methodology for finite dimensional control of a class of linear evolution equations on a Banach space. The design is for stability in an input-output sense, but particular attention is paid to internal stability as well.

International Conference on Artificial Immune Systems (1st) ICARIS 2002, held on 9, 10, and 11 September 2002

DTIC Science & Technology

2002-03-07

Michalewicz, Eds., Evolutionary Computation 1: Basic Algorithms and Operators, Institute of Physics, Bristol (UK), 2000. [3] David A. Van Veldhuizen ...2000. [4] Carlos A. Coello Coello, David A. Van Veldhuizen , and Gary B. Lamont, Evolutionary Algorithms for Solving Multi-Objective Problems, Kluwer...Academic Publishers, 233 Spring St., New York, NY 10013, 2002. [5] David A. Van Veldhuizen , Multiobjective Evolution- ary Algorithms: Classifications

Iran: The Post-Revolutionary Evolution

DTIC Science & Technology

2008-12-01

posts should have knowledge of Sharia law (Islamic law), and the country’s ruler should Figure 1: Iran’s Government Structure 7 be a faqih, someone...whose knowledge of Islamic law and justice was superior to that of others.2 Iran’s political system is a complex mix of Islamic theocracy and...relations theorist, attempts to understand the causes of international war. To do this, he considers three levels of analysis, what he calls “images

Refined applications of the collapse of the wave function

NASA Astrophysics Data System (ADS)

Stodolsky, L.

2015-05-01

In a two-part system, the collapse of the wave function of one part can put the other part in a state which would be difficult or impossible to achieve otherwise, in particular, one sensitive to small effects in the "collapse" interaction. We present some applications to the very symmetric and experimentally accessible situations of the decays ϕ (1020 )→KoKo , ψ (3770 )→DoDo, or ϒ (4 s )→BoBo , involving the internal state of the two-state Ko, Do, or Bo mesons. The collapse of the wave function occasioned by a decay of one member of the pair (away side) fixes the state vector of that side's two-state system. Bose-Einstein statistics then determines the state of the recoiling meson (near side), whose evolution can then be followed further. In particular, the statistics requirement dictates that the "away side" and "near side" internal wave functions must be orthogonal at the time of the collapse. Thus a C P violation in the away side decay implies a complementary C P impurity on the near side, which can be detected in the further evolution. The C P violation so manifested is necessarily direct C P violation, since neither the mass matrix nor time evolution was involved in the collapse. A parametrization of the direct C P violation is given, and various manifestations are presented. Certain rates or combination of rates are identified which are nonzero only if there is direct C P violation. The very explicit and detailed use made of the collapse of the wave function makes the procedure interesting with respect to the fundamentals of quantum mechanics. We note an experimental consistency test for our treatment of the collapse of the wave function, which can be carried out by a certain measurement of partial decay rates.

Chance vs. necessity in living systems: a false antinomy.

PubMed

Buiatti, Marcello; Buiatti, Marco

2008-01-01

The concepts of order and randomness are crucial to understand 'living systems' structural and dynamical rules. In the history of biology, they lay behind the everlasting debate on the relative roles of chance and determinism in evolution. Jacques Monod [1970] built a theory where chance (randomness) and determinism (order) were considered as two complementary aspects of life. In the present paper, we will give an up to date version of the problem going beyond the dichotomy between chance and determinism. To this end, we will first see how the view on living systems has evolved from the mechanistic one of the 19th century to the one stemming from the most recent literature, where they emerge as complex systems continuously evolving through multiple interactions among their components and with the surrounding environment. We will then report on the ever increasing evidence of "friendly" co-existence in living beings between a number of "variability generators", fixed by evolution, and the "spontaneous order" derived from interactions between components. We will propose that the "disorder" generated is "benevolent" because it allows living systems to rapidly adapt to changes in the environment by continuously changing, while keeping their internal harmony.

The Evolving Role of Information Technology in Haemovigilance Systems

PubMed Central

Condeço, Jorge; Escoval, Maria Antónia; Faber, Jean-Claude

2018-01-01

This work provides an overview and appraisal of the general evolution of IS/IT in haemovigilance, from which lessons can be learned for its future strategic management. An electronic survey was conducted among the members of the International Haemovigilance Network to compile information on the mechanisms implemented to gather, process, validate, and store these data, to monitor haemovigilance activity, and to produce analytical reports. Survey responses were analysed by means of descriptive statistics, and comments/observations were considered in the final discussion. The answers received from 23 haemovigilance organizations show a direct relationship between the number of collected notifications (i.e., communication of adverse effects and events) and the technical specifications of the haemovigilance system in use. Notably, IT is used in the notification reception of 17 of these systems, out of which 8 systems are exclusively based on Web solutions. Most assessments of the evolution of IS/IT tend to focus on the scalability and flexibility of data gathering and reporting, considering the ever-changing requirements of haemovigilance. Data validation is poorly implemented, and data reporting has not reached its full potential. Web-based solutions are seen as the most intuitive and flexible for a system-user interaction. PMID:29707185

Nuclear Engine System Simulation (NESS) version 2.0

NASA Technical Reports Server (NTRS)

Pelaccio, Dennis G.; Scheil, Christine M.; Petrosky, Lyman J.

1993-01-01

The topics are presented in viewgraph form and include the following; nuclear thermal propulsion (NTP) engine system analysis program development; nuclear thermal propulsion engine analysis capability requirements; team resources used to support NESS development; expanded liquid engine simulations (ELES) computer model; ELES verification examples; NESS program development evolution; past NTP ELES analysis code modifications and verifications; general NTP engine system features modeled by NESS; representative NTP expander, gas generator, and bleed engine system cycles modeled by NESS; NESS program overview; NESS program flow logic; enabler (NERVA type) nuclear thermal rocket engine; prismatic fuel elements and supports; reactor fuel and support element parameters; reactor parameters as a function of thrust level; internal shield sizing; and reactor thermal model.

Flight Planning for the International Space Station-Levitation Observation of Dendrite Evolution in Steel Ternary Alloy Rapid Solidification

NASA Technical Reports Server (NTRS)

Flemings, M. C.; Matson, D. M.; Loser, W.; Hyers, R. W.; Rogers, J. R.; Curreri, Peter A. (Technical Monitor)

2002-01-01

The paper is an overview of the status and science for the LODESTARS (Levitation Observation of Dendrite Evolution in Steel Ternary Alloy Rapid Solidification) research project. The program is aimed at understanding how melt convection influences phase selection and the evolution of rapid solidification microstructures.

Thermal Evolution of Neutron Stars

NASA Astrophysics Data System (ADS)

Geppert, Ulrich R. M. E.

The thermal evolution of neutron stars is a subject of intense research, both theoretical and observational. The evolution depends very sensitively on the state of dense matter at supranuclear densities, which essentially controls the neutrino emission. The evolution depends, too, on the structure of the stellar outer layers which control the photon emission. Various internal heating processes and the magnetic field strength and structure will influence the thermal evolution. Of great importance for the cooling processes is also whether, when, and where superfluidity and superconductivity appear within the neutron star. This article describes and discusses these issues and presents neutron star cooling calculations based on a broad collection of equations of state for neutron star matter and internal magnetic field geometries. X-ray observations provide reliable data, which allow conclusions about the surface temperatures of neutron stars. To verify the thermal evolution models, the results of model calculations are compared with the body of observed surface temperatures and their distribution. Through these comparisons, a better understanding can be obtained of the physical processes that take place under extreme conditions in the interior of neutron

The International Space Station Evolution Data Book: An Overview and Status

NASA Technical Reports Server (NTRS)

Antol, Jeffrey; Jorgensen, Catherine A.

1999-01-01

The evolution and enhancement of the International Space Station (ISS) is currently being planned in conjunction with the on-orbit construction of the baseline configuration. Three principal areas have been identified that will contribute to the evolution of ISS: Pre-Planned Program Improvement (P3I), Utilization & Commercialization, and Human Exploration and Development of Space (HEDS) missions. The ISS Evolution Strategy, under development by the Spacecraft and Sensors Branch of NASA Langley Research Center, seeks to coordinate the P3I technology development with Commercialization/Utilization activities and HEDS advanced mission accommodation to provide synergistic technology developments for all three areas. The focal point of this proposed strategy is the ISS Evolution Data Book (EDB), a tool for aiding the evolution and enhancement of ISS beyond Assembly Complete. This paper will discuss the strategy and provide an overview of the EDB, describing the contents of each section. It will also discuss potential applications of the EDB and present an example Design Reference Mission (DRM). The latest status of the EDB and the plans for completing and enhancing the book will also be summarized.

Generation of long subharmonic internal waves by surface waves

NASA Astrophysics Data System (ADS)

Tahvildari, Navid; Kaihatu, James M.; Saric, William S.

2016-10-01

A new set of Boussinesq equations is derived to study the nonlinear interactions between long waves in a two-layer fluid. The fluid layers are assumed to be homogeneous, inviscid, incompressible, and immiscible. Based on the Boussinesq equations, an analytical model is developed using a second-order perturbation theory and applied to examine the transient evolution of a resonant triad composed of a surface wave and two oblique subharmonic internal waves. Wave damping due to weak viscosity in both layers is considered. The Boussinesq equations and the analytical model are verified. In contrast to previous studies which focus on short internal waves, we examine long waves and investigate some previously unexplored characteristics of this class of triad interaction. In viscous fluids, surface wave amplitudes must be larger than a threshold to overcome viscous damping and trigger internal waves. The dependency of this critical amplitude as well as the growth and damping rates of internal waves on important parameters in a two-fluid system, namely the directional angle of the internal waves, depth, density, and viscosity ratio of the fluid layers, and surface wave amplitude and frequency is investigated.

SRMS History, Evolution and Lessons Learned

NASA Technical Reports Server (NTRS)

Jorgensen, Glenn; Bains, Elizabeth

2011-01-01

Early in the development of the Space Shuttle, it became clear that NASA needed a method of deploying and retrieving payloads from the payload bay. The Shuttle Remote Manipulator System (SRMS) was developed to fill this need. The 50 foot long robotic arm is an anthropomorphic design consisting of three electromechanical joints, six degrees of freedom, and two boom segments. Its composite boom construction provided a light weight solution needed for space operations. Additionally, a method of capturing payloads with the arm was required and a unique End Effector was developed using an electromechanical snare mechanism. The SRMS is operated using a Displays and Controls Panel and hand controllers located within the aft crew compartment of the shuttle. Although the SRMS was originally conceived to deploy and retrieve payloads, its generic capabilities allowed it to perform many other functions not originally conceived of. Over the years it has been used for deploying and retrieving constrained and free flying payloads, maneuvering and supporting EVA astronauts, satellite repair, International Space Station construction, and as a viewing aid for on-orbit International Space Station operations. After the Columbia accident, a robotically compatible Orbiter Boom Sensor System (OBSS) was developed and used in conjunction with the SRMS to scan the Thermal Protection System (TPS) of the shuttle. These scans ensure there is not a breach of the TPS prior to shuttle re-entry. Ground operations and pre mission simulation, analysis and planning played a major role in the success of the SRMS program. A Systems Engineering Simulator (SES) was developed to provide a utility complimentary to open loop engineering simulations. This system provided a closed-loop real-time pilot-driven simulation giving visual feedback, display and control panel interaction, and integration with other vehicle systems, such as GN&C. It has been useful for many more applications than traditional training. Evolution of the simulations, guided by the Math Model Working Group, showed the utility of input from multiple modeling groups with a structured forum for discussion.There were many unique development challenges in the areas of hardware, software, certification, modeling and simulation. Over the years, upgrades and enhancements were implemented to increase the capability, performance and safety of the SRMS. The history and evolution of the SRMS program provided many lessons learned that can be used for future space robotic systems.

The hidden hyperbolic geometry of international trade: World Trade Atlas 1870–2013

PubMed Central

García-Pérez, Guillermo; Boguñá, Marián; Allard, Antoine; Serrano, M. Ángeles

2016-01-01

Here, we present the World Trade Atlas 1870–2013, a collection of annual world trade maps in which distance combines economic size and the different dimensions that affect international trade beyond mere geography. Trade distances, based on a gravity model predicting the existence of significant trade channels, are such that the closer countries are in trade space, the greater their chance of becoming connected. The atlas provides us with information regarding the long-term evolution of the international trade system and demonstrates that, in terms of trade, the world is not flat but hyperbolic, as a reflection of its complex architecture. The departure from flatness has been increasing since World War I, meaning that differences in trade distances are growing and trade networks are becoming more hierarchical. Smaller-scale economies are moving away from other countries except for the largest economies; meanwhile those large economies are increasing their chances of becoming connected worldwide. At the same time, Preferential Trade Agreements do not fit in perfectly with natural communities within the trade space and have not necessarily reduced internal trade barriers. We discuss an interpretation in terms of globalization, hierarchization, and localization; three simultaneous forces that shape the international trade system. PMID:27633649

HOT Faults", Fault Organization, and the Occurrence of the Largest Earthquakes

NASA Astrophysics Data System (ADS)

Carlson, J. M.; Hillers, G.; Archuleta, R. J.

2006-12-01

We apply the concept of "Highly Optimized Tolerance" (HOT) for the investigation of spatio-temporal seismicity evolution, in particular mechanisms associated with largest earthquakes. HOT provides a framework for investigating both qualitative and quantitative features of complex feedback systems that are far from equilibrium and punctuated by rare, catastrophic events. In HOT, robustness trade-offs lead to complexity and power laws in systems that are coupled to evolving environments. HOT was originally inspired by biology and engineering, where systems are internally very highly structured, through biological evolution or deliberate design, and perform in an optimum manner despite fluctuations in their surroundings. Though faults and fault systems are not designed in ways comparable to biological and engineered structures, feedback processes are responsible in a conceptually comparable way for the development, evolution and maintenance of younger fault structures and primary slip surfaces of mature faults, respectively. Hence, in geophysical applications the "optimization" approach is perhaps more aptly replaced by "organization", reflecting the distinction between HOT and random, disorganized configurations, and highlighting the importance of structured interdependencies that evolve via feedback among and between different spatial and temporal scales. Expressed in the terminology of the HOT concept, mature faults represent a configuration optimally organized for the release of strain energy; whereas immature, more heterogeneous fault networks represent intermittent, suboptimal systems that are regularized towards structural simplicity and the ability to generate large earthquakes more easily. We discuss fault structure and associated seismic response pattern within the HOT concept, and outline fundamental differences between this novel interpretation to more orthodox viewpoints like the criticality concept. The discussion is flanked by numerical simulations of a 2D fault model, where we investigate different feedback mechanisms and their effect on seismicity evolution. We introduce an approach to estimate the state of a fault and thus its capability of generating a large (system-wide) event assuming likely heterogeneous distributions of hypocenters and stresses, respectively.

Thermodynamics of Terrestrial Evolution

PubMed Central

Kirkaldy, J. S.

1965-01-01

The causal element of biological evolution and development can be understood in terms of a potential function which is generalized from the variational principles of irreversible thermodynamics. This potential function is approximated by the rate of entropy production in a configuration space which admits of macroscopic excursions by fluctuation and regression as well as microscopic ones. Analogously to Onsager's dissipation function, the potential takes the form of a saddle surface in this configuration space. The path of evolution following from an initial high dissipation state within the fixed constraint provided by the invariant energy flux from the sun tends toward the stable saddle point by a series of spontaneous regressions which lower the entropy production rate and by an alternating series of spontaneous fluctuations which introduce new internal constraints and lead to a higher entropy production rate. The potential thus rationalizes the system's observed tendency toward “chemical imperialism” (high dissipation) while simultaneously accommodating the development of “dynamic efficiency” and complication (low dissipation). PMID:5884019

Research at the Institute of Astronomy and Astrophysics of the Université Libre de Bruxelles

NASA Astrophysics Data System (ADS)

Karinkuzhi, Drisya; Chamel, Nicolas; Goriely, Stéphane; Jorissen, Alain; Pourbaix, Dimitri; Siess, Lionel; Van Eck, Sophie

2018-04-01

Over the years, a coherent research strategy has developed in the field of stellar physics at the Institute of Astronomy and Astrophysics (IAA). It involves observational studies (chemical composition of giant stars, binary properties, tomography of stellar atmospheres) that make use of the large ESO telescopes as well as of other major instruments. The presence of a high-resolution spectrograph on the 3.6-m Devasthal Optical Telescope (DOT) would therefore be highly beneficial to IAA research. These observations are complemented and supported by theoretical studies of mass transfer in binary systems, of standard and non-standard stellar evolution (including the modelling of stellar hydrodynamical nuclear burning for application to certain thermonuclear supernovae) and of nuclear astrophysics (a field in which IAA has been recognized for a long time as an international centre of excellence), including the theory of nucleosynthesis. IAA also addresses the end-points of stellar evolution as it is carrying out research on the compact remnants of stellar evolution of massive stars: neutron stars.

Tracking and data systems support for the Helios project. Volume 1: Project development through end of mission, phase 2

NASA Technical Reports Server (NTRS)

Goodwin, P. S.; Traxler, M. R.; Meeks, W. G.; Flanagan, F. M.

1976-01-01

The overall evolution of the Helios Project is summarized from its conception through to the completion of the Helios-1 mission phase 2. Beginning with the project objectives and concluding with the Helios-1 spacecraft entering its first superior conjunction (end of mission phase 2), descriptions of the project, the mission and its phases, international management and interfaces, and Deep Space Network-spacecraft engineering development in telemetry, tracking, and command systems to ensure compatibility between the U.S. Deep Space Network and the German-built spacecraft are included.

Complexity and robustness

PubMed Central

Carlson, J. M.; Doyle, John

2002-01-01

Highly optimized tolerance (HOT) was recently introduced as a conceptual framework to study fundamental aspects of complexity. HOT is motivated primarily by systems from biology and engineering and emphasizes, (i) highly structured, nongeneric, self-dissimilar internal configurations, and (ii) robust yet fragile external behavior. HOT claims these are the most important features of complexity and not accidents of evolution or artifices of engineering design but are inevitably intertwined and mutually reinforcing. In the spirit of this collection, our paper contrasts HOT with alternative perspectives on complexity, drawing on real-world examples and also model systems, particularly those from self-organized criticality. PMID:11875207

Dynamical Stability and Long-term Evolution of Rotating Stellar Systems

NASA Astrophysics Data System (ADS)

Varri, Anna L.; Vesperini, E.; McMillan, S. L. W.; Bertin, G.

2011-05-01

We present the first results of an extensive survey of N-body simulations designed to investigate the dynamical stability and the long-term evolution of two new families of self-consistent stellar dynamical models, characterized by the presence of internal rotation. The first family extends the well-known King models to the case of axisymmetric systems flattened by solid-body rotation while the second family is characterized by differential rotation. The equilibrium configurations thus obtained can be described in terms of two dimensionless parameters, which measure the concentration and the amount of rotation, respectively. Slowly rotating configurations are found to be dynamically stable and we followed their long-term evolution, in order to evaluate the interplay between collisional relaxation and angular momentum transport. We also studied the stability of rapidly rotating models, which are characterized by the presence of a toroidal core embedded in an otherwise quasi-spherical configuration. In both cases, a description in terms of the radial and global properties, such as the ratio between the ordered kinetic energy and the gravitational energy of the system, is provided. Because the role of angular momentum in the process of cluster formation is only partly understood, we also undertook a preliminary investigation of the violent relaxation of simple systems initially characterized by approximate solid-body rotation. The properties of the final equilibrium configurations thus obtained are compared with those of the above-described family of differentially rotating models.

Alloplastic temporomandibular joint replacement systems: a systematic review of their history.

PubMed

De Meurechy, N; Mommaerts, M Y

2018-06-01

This systematic review provides an overview of the historical evolution of the prosthetic temporomandibular joint and addresses the challenges and complications faced by engineers and surgeons, in an effort to shed light on why only a few systems remain available. A better understanding of the history of temporomandibular joint prostheses might also provide insights into the origin of the negative public opinion of the prosthesis, which is based on outdated information. A computerized search using the PubMed Central, ScienceDirect, Wiley Online, Ovid, and Cochrane Library databases was performed following the PRISMA guidelines. Out of 7122 articles identified, 41 met the inclusion criteria for this systematic review. Although several historical reviews have been published previously, none has covered such an extensive time period or has described all designs. Furthermore, besides providing a historical overview, this review discusses the rationale behind the evolution in design and biomaterials, which have largely contributed to the outcomes of the prosthetic systems. Copyright © 2018 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Designing Mission Operations for the Gravity Recovery and Interior Laboratory Mission

NASA Technical Reports Server (NTRS)

Havens, Glen G.; Beerer, Joseph G.

2012-01-01

NASA's Gravity Recovery and Interior Laboratory (GRAIL) mission, to understand the internal structure and thermal evolution of the Moon, offered unique challenges to mission operations. From launch through end of mission, the twin GRAIL orbiters had to be operated in parallel. The journey to the Moon and into the low science orbit involved numerous maneuvers, planned on tight timelines, to ultimately place the orbiters into the required formation-flying configuration necessary. The baseline GRAIL mission is short, only 9 months in duration, but progressed quickly through seven very unique mission phases. Compressed into this short mission timeline, operations activities and maneuvers for both orbiters had to be planned and coordinated carefully. To prepare for these challenges, development of the GRAIL Mission Operations System began in 2008. Based on high heritage multi-mission operations developed by NASA's Jet Propulsion Laboratory and Lockheed Martin, the GRAIL mission operations system was adapted to meet the unique challenges posed by the GRAIL mission design. This paper describes GRAIL's system engineering development process for defining GRAIL's operations scenarios and generating requirements, tracing the evolution from operations concept through final design, implementation, and validation.

Protocol Interoperability Between DDN and ISO (Defense Data Network and International Organization for Standardization) Protocols

DTIC Science & Technology

1988-08-01

Interconnection (OSI) in years. It is felt even more urgent in the past few years, with the rapid evolution of communication technologies and the...services and protocols above the transport layer are usually implemented as user- callable utilities on the host computers, it is desirable to offer them...Networks, Prentice-hall, New Jersey, 1987 [ BOND 87] Bond , John, "Parallel-Processing Concepts Finally Come together in Real Systems", Computer Design

Perceptions of High School Biology Teachers in Christian Schools on Relationships between Religious Beliefs and Teaching Evolution

ERIC Educational Resources Information Center

Mangahas, Ana Marie E.

2017-01-01

This mixed method study explored Christian teachers' beliefs in religious schools on evolution, their attitudes toward evolution, and their perceptions on the effect of those beliefs on the teaching of evolutionary content. Teachers (N = 52) from Association for Christian Schools International (ACSI) accredited schools in California and Hawaii…

In Situ Probe Science at Saturn

NASA Technical Reports Server (NTRS)

Atkinson, D.H.; Lunine, J.I.; Simon-Miller, A. A.; Atreya, S. K.; Brinckerhoff, W.; Colaprete, A.; Coustenis, A.; Fletcher, L. N.; Guillot, T.; Lebreton, J.-P.;

Recognition of hyper-extended rifted margin remnants in the internal zone of the Alpine belt: A tribute to Marco Beltrando

NASA Astrophysics Data System (ADS)

Mohn, Geoffroy; Manatschal, Gianreto

2016-04-01

Marco Beltrando was part of the young generation of Alpine geologists who challenged the interpretation of the Western Alps by combining a classical field approach and modern techniques (e.g. 40Ar/39Ar and (U-Th)/He thermochronology). His work provides the foundation to re-interpret some of the classical sections through the Alpine belt and may impact the way of thinking about the nature and structure of internal parts of collisional orogens. This contribution will present the main outcomes of the work of Marco Beltrando and their implications for the understanding of Alpine type orogens. Since his PhD, Marco Beltrando focused most of his work on the study of the internal parts of the Western Alps. He investigated in great details the complex, multiphase structural and metamorphic evolution of the Penninic units in the Western Alps. He concluded that these units went through several cycles of shortening and extension during the Alpine orogeny, with major implications for the Alps but also other orogenic belts. After his PhD, he focused his research on the pre-orogenic evolution of the Alpine belt. He first worked on the Petit St. Bernard area, where he identified relics of the former hyper-extended Tethyan rifted margin. Thanks to his work and his amazing knowledge of the Western Alps, he understood the potential importance of rift-inheritance in controlling the architecture and evolution of the Alpine belt. In parallel to the study of the orogenic evolution, he developed a new methodology to recognize rift-related lithostratigraphic units in highly deformed and metamorphosed parts of the Alps. His innovative work allowed a re-assessment of several areas in the Western Alps and demonstrates the importance of rift inheritance. Recently, he started a new research project on the evolution of the Southern Alps highlighting the importance of heating and cooling cycles resulting from complex successions of rifting events. In spite of his young age, Marco Beltrando was at the forefront of new techniques, ideas and concepts that ultimately will improve our understanding of mountain belts and rift systems. Eventually more than anything, his motivation and enthusiasm were a constant source of inspiration.

Evolution of Nonlinear Internal Waves in China Seas

NASA Technical Reports Server (NTRS)

Liu, Antony K.; Hsu, Ming-K.; Liang, Nai K.

1997-01-01

Synthetic Aperture Radar (SAR) images from ERS-I have been used to study the characteristics of internal waves of Taiwan in the East China Sea, and east of Hainan Island in the South China Sea. Rank-ordered packets of internal solitons propagating shoreward from the edge of the continental shelf were observed in the SAR images. Based on the assumption of a semidiurnal tidal origin, the wave speed can be estimated and is consistent with the internal wave theory. By using the SAR images and hydrographic data, internal waves of elevation have been identified in shallow water due to a thicker mixed layer as compared with the bottom layer on the continental shelf. The generation mechanism includes the influences of the tide and the Kuroshio intrusion across the continental shelf for the formations of elevation internal waves. The effects of water depth on the evolution of solitons and wave packets are modeled by nonlinear Kortweg-deVries (KdV) type equation and linked to satellite image observations. The numerical calculations of internal wave evolution on the continental shelf have been performed and compared with the SAR observations. For a case of depression waves in deep water, the solitons first disintegrate into dispersive wave trains and then evolve to a packet of elevation waves in the shallow water area after they pass through a turning point of approximately equal layer depths has been observed in the SAR image and simulated by numerical model.

Semiautomatic segmentation and follow-up of multicomponent low-grade tumors in longitudinal brain MRI studies

PubMed Central

Weizman, Lior; Sira, Liat Ben; Joskowicz, Leo; Rubin, Daniel L.; Yeom, Kristen W.; Constantini, Shlomi; Shofty, Ben; Bashat, Dafna Ben

2014-01-01

Purpose: Tracking the progression of low grade tumors (LGTs) is a challenging task, due to their slow growth rate and associated complex internal tumor components, such as heterogeneous enhancement, hemorrhage, and cysts. In this paper, the authors show a semiautomatic method to reliably track the volume of LGTs and the evolution of their internal components in longitudinal MRI scans. Methods: The authors' method utilizes a spatiotemporal evolution modeling of the tumor and its internal components. Tumor components gray level parameters are estimated from the follow-up scan itself, obviating temporal normalization of gray levels. The tumor delineation procedure effectively incorporates internal classification of the baseline scan in the time-series as prior data to segment and classify a series of follow-up scans. The authors applied their method to 40 MRI scans of ten patients, acquired at two different institutions. Two types of LGTs were included: Optic pathway gliomas and thalamic astrocytomas. For each scan, a “gold standard” was obtained manually by experienced radiologists. The method is evaluated versus the gold standard with three measures: gross total volume error, total surface distance, and reliability of tracking tumor components evolution. Results: Compared to the gold standard the authors' method exhibits a mean Dice similarity volumetric measure of 86.58% and a mean surface distance error of 0.25 mm. In terms of its reliability in tracking the evolution of the internal components, the method exhibits strong positive correlation with the gold standard. Conclusions: The authors' method provides accurate and repeatable delineation of the tumor and its internal components, which is essential for therapy assessment of LGTs. Reliable tracking of internal tumor components over time is novel and potentially will be useful to streamline and improve follow-up of brain tumors, with indolent growth and behavior. PMID:24784396

Adaptive Modeling of the International Space Station Electrical Power System

NASA Technical Reports Server (NTRS)

Thomas, Justin Ray

2007-01-01

Software simulations provide NASA engineers the ability to experiment with spacecraft systems in a computer-imitated environment. Engineers currently develop software models that encapsulate spacecraft system behavior. These models can be inaccurate due to invalid assumptions, erroneous operation, or system evolution. Increasing accuracy requires manual calibration and domain-specific knowledge. This thesis presents a method for automatically learning system models without any assumptions regarding system behavior. Data stream mining techniques are applied to learn models for critical portions of the International Space Station (ISS) Electrical Power System (EPS). We also explore a knowledge fusion approach that uses traditional engineered EPS models to supplement the learned models. We observed that these engineered EPS models provide useful background knowledge to reduce predictive error spikes when confronted with making predictions in situations that are quite different from the training scenarios used when learning the model. Evaluations using ISS sensor data and existing EPS models demonstrate the success of the adaptive approach. Our experimental results show that adaptive modeling provides reductions in model error anywhere from 80% to 96% over these existing models. Final discussions include impending use of adaptive modeling technology for ISS mission operations and the need for adaptive modeling in future NASA lunar and Martian exploration.

Adaptive laboratory evolution resolves energy depletion to maintain high aromatic metabolite phenotypes in Escherichia coli strains lacking the Phosphotransferase System.

PubMed

McCloskey, Douglas; Xu, Sibei; Sandberg, Troy E; Brunk, Elizabeth; Hefner, Ying; Szubin, Richard; Feist, Adam M; Palsson, Bernhard O

2018-06-15

Aromatic metabolites provide the backbone for numerous industrial and pharmaceutical compounds of high value. The Phosphotransferase System (PTS) is common to many bacteria, and is the primary mechanism for glucose uptake by Escherichia coli. The PTS was removed to conserve phosphoenolpyruvate (pep), which is a precursor for aromatic metabolites and consumed by the PTS, for aromatic metabolite production. Replicate adaptive laboratory evolution (ALE) of PTS and detailed omics data sets collected revealed that the PTS bridged the gap between respiration and fermentation, leading to distinct high fermentative and high respiratory rate phenotypes. It was also found that while all strains retained high levels of aromatic amino acid (AAA) biosynthetic precursors, only one replicate from the high glycolytic clade retained high levels of intracellular AAAs. The fast growth and high AAA precursor phenotypes could provide a starting host for cell factories targeting the overproduction aromatic metabolites. Copyright © 2018 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

The Metallicity of Void Dwarf Galaxies

NASA Astrophysics Data System (ADS)

Kreckel, K.; Croxall, K.; Groves, B.; van de Weygaert, R.; Pogge, R. W.

2015-01-01

The current ΛCDM cosmological model predicts that galaxy evolution proceeds more slowly in lower density environments, suggesting that voids are a prime location to search for relatively pristine galaxies that are representative of the building blocks of early massive galaxies. To test the assumption that void galaxies are more pristine, we compare the evolutionary properties of a sample of dwarf galaxies selected specifically to lie in voids with a sample of similar isolated dwarf galaxies in average density environments. We measure gas-phase oxygen abundances and gas fractions for eight dwarf galaxies (Mr > -16.2), carefully selected to reside within the lowest density environments of seven voids, and apply the same calibrations to existing samples of isolated dwarf galaxies. We find no significant difference between these void dwarf galaxies and the isolated dwarf galaxies, suggesting that dwarf galaxy chemical evolution proceeds independent of the large-scale environment. While this sample is too small to draw strong conclusions, it suggests that external gas accretion is playing a limited role in the chemical evolution of these systems, and that this evolution is instead dominated mainly by the internal secular processes that are linking the simultaneous growth and enrichment of these galaxies.

Fail-Safe Design for Large Capacity Lithium-Ion Battery Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, G. H.; Smith, K.; Ireland, J.

2012-07-15

A fault leading to a thermal runaway in a lithium-ion battery is believed to grow over time from a latent defect. Significant efforts have been made to detect lithium-ion battery safety faults to proactively facilitate actions minimizing subsequent losses. Scaling up a battery greatly changes the thermal and electrical signals of a system developing a defect and its consequent behaviors during fault evolution. In a large-capacity system such as a battery for an electric vehicle, detecting a fault signal and confining the fault locally in the system are extremely challenging. This paper introduces a fail-safe design methodology for large-capacity lithium-ionmore » battery systems. Analysis using an internal short circuit response model for multi-cell packs is presented that demonstrates the viability of the proposed concept for various design parameters and operating conditions. Locating a faulty cell in a multiple-cell module and determining the status of the fault's evolution can be achieved using signals easily measured from the electric terminals of the module. A methodology is introduced for electrical isolation of a faulty cell from the healthy cells in a system to prevent further electrical energy feed into the fault. Experimental demonstration is presented supporting the model results.« less

The self and the nonself: immunorecognition and immunologic functions.

PubMed

del Guercio, P

1993-01-01

For almost a century self-nonself discrimination has been considered the driving force of the immune system and the dogma of self-tolerance (horror autotoxicus) the essential issue for understanding protective immunity and pathologic autoreactivity. This classical picture has been recently challenged by the discovery that the immune system is influenced by internal activation (amor autocognitus) and autoreactive clones are both present and activated in healthy individuals. Central to the concepts of reactivity and tolerance, in other terms, to physiology and pathology, is the analysis of structures involved in immunorecognition and as they contribute to the outcome of the immune response. The capacity of the immune system to recognize nonself structures and eventually react to them developed during evolution probably before the generation of clonally distributed antigen receptors. The high level of autoreactivity that characterizes the immune system seems to suggest that immunocompetent cells never learned to ignore the self, but rather that, sometime during evolution, they specialized in the function of self-identification, one of the most basic activities of all living cells. Autoimmune diseases would result from a pathologic deviation of a physiologic function, just as many other diseases do.

Selfish cells in altruistic cell society - a theoretical oncology.

PubMed

Chigira, M

1993-09-01

In multicellular organisms, internal evolution of individual cells is strictly forbidden and 'evolutional' DNA replication should be performed only by the sexual reproduction system. Wholistic negative control system called 'homeostasis' serves all service to germ line cells. All somatic cells are altruistic to the germ line cells. However, in malignant tumors, it seems that individual cells replicate and behave 'selfishly' and evolve against the internal microenvironment. Tumor cells only express the occult selfishness which is programmed in normal cells a priori. This phenomenon is based on the failure of identical DNA replication, and results in 'autonomy' and 'anomie' of cellular society as shown in tumor cells. Genetic programs of normal cells connote this cellular autonomy and anomie introduced by the deletion of regulators on structure genes. It is rather paradoxical that the somatic cells get their freedom from wholistic negative regulation programmed internally. However, this is not a true paradox, since multicellular organisms have clearly been evolved from 'monads' in which cells proliferate without wholistic regulation. Somatic cells revolt against germ cell DNA, called 'selfish replicator' by Dawkins. It is an inevitable destiny that the 'selfishness' coded in genome should be revenged by itself. Selfish replicator in germ cell line should be revolted by its selfishness in the expansion of somatic cells, since they have an orthogenesis to get more selfishness in order to increase their genome. Tumor heterogeneity and progression can be fully explained by this self-contradictory process which produces heterogeneous gene copies different from the original clone in the tumor, although 'selfish' gene replication is the final target of being. Furthermore, we have to discard the concept of clonality of tumor cells since genetic instability is a fundamental feature of tumors. Finally, tumor cells and proto-oncogenes can be considered as the ultimate parasite to germ line cells.

La Galite Archipelago (Tunisia, North Africa): Stratigraphic and petrographic revision and insights for geodynamic evolution of the Maghrebian Chain

NASA Astrophysics Data System (ADS)

Belayouni, Habib; Brunelli, Daniele; Clocchiatti, Roberto; Di Staso, Angelida; El Hassani, Iz-Eddine El Amrani; Guerrera, Francesco; Kassaa, Samia; Ouazaa, Nejia Laridhi; Martín, Manuel Martín; Serrano, Francisco; Tramontana, Mario

2010-01-01

The location of the La Galite Archipelago on the Internal/External Zones of the Maghrebian Chain holds strong interest for the reconstruction of the geodynamic evolution of the Mesomediterranean Microplate-Africa Plate Boundary Zone. New stratigraphic and petrographic data on sedimentary successions intruded upon by plutonic rocks enabled a better definition of the palaeogeographic and palaeotectonic evolutionary model of the area during the early-middle Miocene. The lower Miocene sedimentary units ( La Galite Flysch and Numidian-like Flysch) belong to the Mauritanian (internal) and Massylian (external) sub-Domains of the Maghrebian Chain, respectively. These deposits are related to a typical syn-orogenic deposition in the Maghrebian Flysch Basin Domain, successively backthrusted above the internal units. The backthrusting age is post-Burdigalian (probably Langhian-Serravallian) and the compressional phase represents the last stage in the building of the accretionary wedge of the Maghrebian orogen. These flysch units may be co-relatable to the similar well-known formations along the Maghrebian and Betic Chains. The emplacement of potassic peraluminous magmatism, caused local metamorphism in the Late Serravallian-Early Tortonian (14-10 Ma), after the last compressional phase (backthrusting), during an extensional tectonic event. This extensional phase is probably due to the opening of a slab break-off in the deep subduction system. La Galite Archipelago represents a portion of the Maghrebian Flysch Basin tectonically emplaced above the southern margin of the "Mesomediterranean Microplate" which separated the Piemontese-Ligurian Ocean from a southern oceanic branch of the Tethys (i.e. the Maghrebian Flysch Basin). The possible presence of an imbricate thrust system between La Galite Archipelago and northern Tunisia may be useful to exclude the petroleum exploration from the deformed sectors of the offshore area considered.

Characterization of aircraft dynamic wake vortices and atmospheric turbulence by coherent doppler lidar

NASA Astrophysics Data System (ADS)

Wu, Songhua; Zhai, Xiaochun; Liu, Bingyi; Liu, Jintao

2018-04-01

Field observations for the wake vortices by Coherent Doppler Lidar (CDL) have been carried out at the Beijing Capital International Airport (BCIA) and Tianjin Binhai International Airport (TBIA) to investigate the wake vortices evolution characteristics and the near-ground effect. This paper introduces the dynamic wake vortices and atmospheric turbulence monitoring technique, successfully demonstrating that the CDL can capture the key characteristics of wake vortices in real-time, including wake vortices intensity, spatial-temporal evolution and so forth.

Moored Observations of Internal Waves in Luzon Strait: 3-D Structure, Dissipation, and Evolution

DTIC Science & Technology

2016-03-01

Strait: 3-D Structure, Dissipation, and Evolution Matthew H. Alford Scripps Institution of Oceanography 9500 Gilman Drive, mail code 0213 La...during IWISE. This work is done in collaboration with Craig Lee (APL/UW), and Dan Rudnick and Shaun Johnston at Scripps Institution of Oceanography ...Y.J. Yang, M.-H. Chang, and Q. Li. 2011. From Luzon Strait to Dongsha Plateau: Stages in the life of an internal wave. Oceanography 24(4):64–77

Normative foundations of technology transfer and transnational benefit principles in the UNESCO Universal Declaration on Bioethics and Human Rights.

PubMed

Faunce, Thomas Alured; Nasu, Hitoshi

2009-06-01

The United Nations Scientific, Education, and Cultural Organization Universal Declaration on Bioethics and Human Rights (UDBHR) expresses in its title and substance a controversial linkage of two normative systems: international human rights law and bioethics. The UDBHR has the status of what is known as a "nonbinding" declaration under public international law. The UDBHR's foundation within bioethics (and association, e.g., with virtue-based or principlist bioethical theories) is more problematic. Nonetheless, the UDBHR contains socially important principles of technology transfer and transnational benefit (articles 14, 15, and 21). This paper is one of the first to explore how the disciplines of bioethics and international human rights law may interact in the UDBHR to advance the policy relevance and health impact of such principles. It investigates their normative ancestry in the UDBHR, as well as relevant conceptual differences between bioethics and public international law in this respect, and how these may be relevant to their conceptual evolution and application.

A Cross-Cultural Comparison of Korean and American Science Teachers' Views of Evolution and the Nature of Science

NASA Astrophysics Data System (ADS)

Kim, Sun Young; Nehm, Ross H.

2011-01-01

Despite a few international comparisons of the evolutionary beliefs of the general public, comparatively less research has focused on science teachers. Cross-cultural studies offer profitable opportunities for exploring the interactions among knowledge and belief variables in regard to evolution in different socio-cultural contexts. We investigated the evolutionary worldviews of pre-service science teachers from Asia (specifically South Korea), a region often excluded from international comparisons. We compared Korean and American science teachers': (1) understandings of evolution and the nature of science, and (2) acceptance of evolution in order to elucidate how knowledge and belief relationships are manifested in different cultural contexts. We found that Korean science teachers exhibited 'moderate' evolutionary acceptance levels comparable to or lower than American science teacher samples. Gender was significantly related to Korean teachers' evolution content knowledge and acceptance of evolution, with female Christian biology teachers displaying the lowest values on all measures. Korean science teachers' understandings of nature of science were significantly related to their acceptance and understanding of evolution; this relationship appears to transcend cultural boundaries. Our new data on Korean teachers, combined with studies from more than 20 other nations, expose the global nature of science teacher ambivalence or antipathy toward evolutionary knowledge.

International Space Station as a Platform for Exploration Beyond Low Earth Orbit

NASA Technical Reports Server (NTRS)

Raftery, Michael; Woodcock, Gordon

2010-01-01

The International Space Station (ISS) has established a new model for the achievement of the most difficult engineering goals in space: international collaboration at the program level with competition at the level of technology. This strategic shift in management approach provides long term program stability while still allowing for the flexible evolution of technology needs and capabilities. Both commercial and government sponsored technology developments are well supported in this management model. ISS also provides a physical platform for development and demonstration of the systems needed for missions beyond low earth orbit. These new systems at the leading edge of technology require operational exercise in the unforgiving environment of space before they can be trusted for long duration missions. Systems and resources needed for expeditions can be aggregated and thoroughly tested at ISS before departure thus providing wide operational flexibility and the best assurance of mission success. We will describe representative mission profiles showing how ISS can support exploration missions to the Moon, Mars, asteroids and other potential destinations. Example missions would include humans to lunar surface and return, and humans to Mars orbit as well as Mars surface and return. ISS benefits include: international access from all major launch sites; an assembly location with crew and tools that could help prepare departing expeditions that involve more than one launch; a parking place for reusable vehicles; and the potential to add a propellant depot.

[The internationalization of health: contextual elements and institutional frameworks of Brazilian cooperation].

PubMed

Pires-Alves, Fernando A; Paiva, Carlos Henrique Assunção; de Santana, José Paranaguá

2012-12-01

The article contextualizes the emergence of an international policy for the Brazilian Unified Health System as the common agenda of the Pan American Health Organization (PAHO) and the Brazilian Ministry of Health. For this purpose, two contextual axes were explored throughout the work. The first discusses the explicit relationship between the development-cooperation-health triad from an international perspective. The second examines the recent evolution of Brazilian foreign policy, particularly with respect to the role it is playing in South-South cooperation on health matters. The contextual framework that defines Brazilian international cooperation with PAHO is emphasized, above all with regard to the implementation of a specific cooperation agreement. The article concludes that this agreement, within the framework of South-South cooperation, is one of the principal institutional mechanisms established to bring about technical cooperation in health in the current setting.

A viscoplastic model with application to LiF-22 percent CaF2 hypereutectic salt

NASA Technical Reports Server (NTRS)

Freed, A. D.; Walker, K. P.

1990-01-01

A viscoplastic model for class M (metal-like behavior) materials is presented. One novel feature is its use of internal variables to change the stress exponent of creep (where n is approximately = 5) to that of natural creep (where n = 3), in accordance with experimental observations. Another feature is the introduction of a coupling in the evolution equations of the kinematic and isotropic internal variables, making thermal recovery of the kinematic variable implicit. These features enable the viscoplastic model to reduce to that of steady-state creep in closed form. In addition, the hardening parameters associated with the two internal state variables (one scalar-valued, the other tensor-valued) are considered to be functions of state, instead of being taken as constant-valued. This feature enables each internal variable to represent a much wider spectrum of internal states for the material. The model is applied to a LiF-22 percent CaF2 hypereutectic salt, which is being considered as a thermal energy storage material for space-based solar dynamic power systems.

The tectonometamorphic evolution of the Apuseni Mountains (Romania): Geodynamic constraints for the evolution of the Alps-Carpathians-Dinaride system of orogens

NASA Astrophysics Data System (ADS)

Reiser, Martin; Schuster, Ralf; Fügenschuh, Bernhard

2015-04-01

New structural, thermobarometric and geochronological data allow integrating kinematics, timing and intensity of tectonic phases into a geodynamic model of the Apuseni Mountain, which provides new constraints for the evolution of the Alps-Carpathians-Dinaride system of orogens. Strong differences in terms of deformation directions between Early and Late Cretaceous events provide new constraints on the regional geodynamic evolution during the Cretaceous. Geochronological and structural data evidence a Late Jurassic emplacement of the South Apuseni Ophiolites on top of the Biharia Nappe System (Dacia Mega-Unit), situated in an external position at the European margin. Following the emplacement of the ophiolites, three compressive deformation phases affected the Apuseni Mountains during Alpine orogeny: a) NE-directed in-sequence nappe stacking and regional metamorphic overprinting under amphibolite-facies conditions during the Early Cretaceous ("Austrian Phase"), b) NW-directed thrusting and folding, associated with greenschist-facies overprinting, during the early Late Cretaceous ("Turonian Phase") and c) E-W internal folding together with brittle thrusting during the latest Cretaceous ("Laramian Phase"). Major tectonic unroofing and exhumation at the transition from Early to Late Cretaceous times is documented through new Sm-Nd Grt, Ar-Ar Ms and Rb-Sr Bt ages from the study area and resulted in a complex thermal structure with strong lateral and vertical thermal gradients. Nappe stacking and medium-grade metamorphic overprinting during the Early Cretaceous exhibits striking parallels between the evolution of the Tisza-Dacia Mega-Units and the Austroalpine Nappes (ALCAPA Mega-Unit) and evidences a close connection. However, Late Cretaceous tectonic events in the study area exhibit strong similarities with the Dinarides. Thus, the Apuseni Mountains represent the "missing link" between the Early Cretaceous Meliata subduction (associated with obduction of ophiolites) and the Neotethys subduction during Late Cretaceous times.

Russo-Japanese Relations and the Future of the U.S.-Japanese Alliance

DTIC Science & Technology

1993-01-01

return of the southern Kurils is the Russian sense of threat from the U.S. force structure in the area, coupled with the existence of the U.S. military...intransigence by continuing to allude to a de facto For a historical reviw of the evolution of their decislonmaklng system. see Hiarty Gdninn, De jam...Foreign Minister Mikhail Kapits . 4K(ovulenko was head of the Japan section of the Central Committee International Departmenit from 1963, and a deputy chief

Evolution of Timescales from Astronomy to Physical Metrology

DTIC Science & Technology

2011-07-20

2000 [7] recommended the use of the ‘non-rotating origin’ both in the Geocentric Celestial Reference System (GCRS) and the International Terrestrial...timescale defined in a geocentric reference frame with the SI second as realized on the rotating geoid as the scale unit’ [30, 31]. This meant that it was...of the new timescale for apparent geocentric ephemerides, will be 1977 January 1d.0003725 (1d 00h 00m 32.184s) exactly. (b) The unit of this timescale

Education and Science in Africa: Possible Ways of Improvement in the Next Decade. International Commission on Education for the Twenty-First Century, Working Group on Education and Science (Paris, France, January 10-11, 1994).

ERIC Educational Resources Information Center

Wandiga, Shem O.

This paper analyzed the evolution of formal education in Africa with emphasis on the weaknesses and strengths of the system identified. Although the roots of modern education can be found in the early institutions of learning and libraries of Alexandria and Timbuktu in Africa, the continent today lags behind in all the fields of formal education.…

Ninth Conference on Space Simulation

NASA Technical Reports Server (NTRS)

1977-01-01

The papers presented in this conference provided an international dialogue and a meaningful exchange in the simulation of space environments as well as the evolution of these technological advances into other fields. The papers represent a significant contribution to the understanding of space simulation problems and the utilization of this knowledge. The topics of the papers include; spacecraft testing; facilities and test equipment; system and subsystem test; life sciences, medicine and space; physical environmental factors; chemical environmental factors; contamination; space physics; and thermal protection.

The physics of neutron stars.

PubMed

Lattimer, J M; Prakash, M

2004-04-23

Neutron stars are some of the densest manifestations of massive objects in the universe. They are ideal astrophysical laboratories for testing theories of dense matter physics and provide connections among nuclear physics, particle physics, and astrophysics. Neutron stars may exhibit conditions and phenomena not observed elsewhere, such as hyperon-dominated matter, deconfined quark matter, superfluidity and superconductivity with critical temperatures near 10(10) kelvin, opaqueness to neutrinos, and magnetic fields in excess of 10(13) Gauss. Here, we describe the formation, structure, internal composition, and evolution of neutron stars. Observations that include studies of pulsars in binary systems, thermal emission from isolated neutron stars, glitches from pulsars, and quasi-periodic oscillations from accreting neutron stars provide information about neutron star masses, radii, temperatures, ages, and internal compositions.

Tool for evaluating the evolution Space Weather Regional Warning Centers under the innovation point of view: the Case Study of the Embrace Space Weather Program Early Stages

NASA Astrophysics Data System (ADS)

Denardini, Clezio Marcos

2016-07-01

We have developed a tool for measuring the evolutional stage of the space weather regional warning centers using the approach of the innovative evolution starting from the perspective presented by Figueiredo (2009, Innovation Management: Concepts, metrics and experiences of companies in Brazil. Publisher LTC, Rio de Janeiro - RJ). It is based on measuring the stock of technological skills needed to perform a certain task that is (or should) be part of the scope of a space weather center. It also addresses the technological capacity for innovation considering the accumulation of technological and learning capabilities, instead of the usual international indices like number of registered patents. Based on this definition, we have developed a model for measuring the capabilities of the Brazilian Study and Monitoring Program Space Weather (Embrace), a program of the National Institute for Space Research (INPE), which has gone through three national stages of development and an international validation step. This program was created in 2007 encompassing competence from five divisions of INPE in order to carry out the data collection and maintenance of the observing system in space weather; to model processes of the Sun-Earth system; to provide real-time information and to forecast space weather; and provide diagnostic their effects on different technological systems. In the present work, we considered the issues related to the innovation of micro-processes inherent to the nature of the Embrace program, not the macro-economic processes, despite recognizing the importance of these. During the development phase, the model was submitted to five scientists/managers from five different countries member of the International Space Environment Service (ISES) who presented their evaluations, concerns and suggestions. It was applied to the Embrace program through an interview form developed to be answered by professional members of regional warning centers. Based on the returning answers we have derived a map that led to the discussions presented in this work. Among them, we point out that the advent of a regional warning center demanded some internal effort to perform the new tasks normally assigned to such center. However, the research activities potential stock available at INPE undoubtedly reduced the leap time among the evolutionary steps. In the other way, once the center was established it produced considerable increase in domestic skills of employees involved in this program. The other conclusions, reflections and recommendations are presented, including a personal reflection on learning processes for technological capability accumulation of what we understand to be present in the Embrace program. Contacting Author: C. M. Denardini (clezio.denardin@inpe.br)

SPALAX new generation: New process design for a more efficient xenon production system for the CTBT noble gas network.

PubMed

Topin, Sylvain; Greau, Claire; Deliere, Ludovic; Hovesepian, Alexandre; Taffary, Thomas; Le Petit, Gilbert; Douysset, Guilhem; Moulin, Christophe

2015-11-01

The SPALAX (Système de Prélèvement Automatique en Ligne avec l'Analyse du Xénon) is one of the systems used in the International Monitoring System of the Comprehensive Nuclear Test Ban Treaty (CTBT) to detect radioactive xenon releases following a nuclear explosion. Approximately 10 years after the industrialization of the first system, the CEA has developed the SPALAX New Generation, SPALAX-NG, with the aim of increasing the global sensitivity and reducing the overall size of the system. A major breakthrough has been obtained by improving the sampling stage and the purification/concentration stage. The sampling stage evolution consists of increasing the sampling capacity and improving the gas treatment efficiency across new permeation membranes, leading to an increase in the xenon production capacity by a factor of 2-3. The purification/concentration stage evolution consists of using a new adsorbent Ag@ZSM-5 (or Ag-PZ2-25) with a much larger xenon retention capacity than activated charcoal, enabling a significant reduction in the overall size of this stage. The energy consumption of the system is similar to that of the current SPALAX system. The SPALAX-NG process is able to produce samples of almost 7 cm(3) of xenon every 12 h, making it the most productive xenon process among the IMS systems. Copyright © 2015 Elsevier Ltd. All rights reserved.

Organically Grown Architectures: Creating Decentralized, Autonomous Systems by Embryomorphic Engineering

NASA Astrophysics Data System (ADS)

Doursat, René

Exploding growth growth in computational systems forces us to gradually replace rigid design and control with decentralization and autonomy. Information technologies will progress, instead, by"meta-designing" mechanisms of system self-assembly, self-regulation and evolution. Nature offers a great variety of efficient complex systems, in which numerous small elements form large-scale, adaptive patterns. The new engineering challenge is to recreate this self-organization and let it freely generate innovative designs under guidance. This article presents an original model of artificial system growth inspired by embryogenesis. A virtual organism is a lattice of cells that proliferate, migrate and self-pattern into differentiated domains. Each cell's fate is controlled by an internal gene regulatory network network. Embryomorphic engineering emphasizes hyperdistributed architectures, and their development as a prerequisite of evolutionary design.

Hydrologic Predictions in the Anthropocene: Exploration with Co-evolutionary Socio-hydrologic Models

NASA Astrophysics Data System (ADS)

Sivapalan, Murugesu; Tian, Fuqiang; Liu, Dengfeng

2013-04-01

Socio-hydrology studies the co-evolution and self-organization of humans in the hydrologic landscape, which requires a thorough understanding of the complex interactions between humans and water. On the one hand, the nature of water availability greatly impacts the development of society. On the other hand, humans can significantly alter the spatio-temporal distribution of water and in this way provide feedback to the society itself. The human-water system functions underlying such complex human-water interactions are not well understood. Exploratory models with the appropriate level of simplification in any given area can be valuable to understand these functions and the self-organization associated with socio-hydrology. In this study, a simple coupled modeling framework for socio-hydrology co-evolution is developed, and is used to illustrate the explanatory power of such models. In the Tarim River, humans depend heavily on agricultural production (other industries can be ignored for a start), and the social processes can be described principally by two variables, i.e., irrigated-area and human population. The eco-hydrological processes are expressed in terms of area under natural vegetation and stream discharge. The study area is the middle and the lower reaches of the Tarim River, which is divided into two modeling units, i.e. middle reach and lower reach. In each modeling unit, four ordinary differential equations are used to simulate the dynamics of the hydrological system represented by stream discharge, ecological system represented by area under natural vegetation, the economic system represented by irrigated area under agriculture and social system represented by human population. The four dominant variables are coupled together by several internal variables. For example, the stream discharge is coupled to irrigated area by the colonization rate and mortality rate of the irrigated area in the middle reach and the irrigated area is coupled to stream discharge by water used for irrigation. In a similar way, the stream discharge and natural vegetation are coupled together. The irrigated area is coupled to population by the colonization rate and mortality rate of the population. The discharge of the lower reach is determined by the discharge from the middle reach. The natural vegetation area in the lower reach is coupled to the discharge in the middle reach by water resources management policy. The co-evolution of the Tarim socio-hydrological system is then analyzed within this modeling framework to gain insights into the overall system dynamics and sensitivity to the external drivers and internal system variables.

A conceptual socio-hydrological model of the co-evolution of humans and water: case study of the Tarim River basin, western China

NASA Astrophysics Data System (ADS)

Liu, D.; Tian, F.; Lin, M.; Sivapalan, M.

2015-02-01

The complex interactions and feedbacks between humans and water are critically important issues but remain poorly understood in the newly proposed discipline of socio-hydrology (Sivapalan et al., 2012). An exploratory model with the appropriate level of simplification can be valuable for improving our understanding of the co-evolution and self-organization of socio-hydrological systems driven by interactions and feedbacks operating at different scales. In this study, a simplified conceptual socio-hydrological model based on logistic growth curves is developed for the Tarim River basin in western China and is used to illustrate the explanatory power of such a co-evolutionary model. The study area is the main stream of the Tarim River, which is divided into two modeling units. The socio-hydrological system is composed of four sub-systems, i.e., the hydrological, ecological, economic, and social sub-systems. In each modeling unit, the hydrological equation focusing on water balance is coupled to the other three evolutionary equations to represent the dynamics of the social sub-system (denoted by population), the economic sub-system (denoted by irrigated crop area ratio), and the ecological sub-system (denoted by natural vegetation cover), each of which is expressed in terms of a logistic growth curve. Four feedback loops are identified to represent the complex interactions among different sub-systems and different spatial units, of which two are inner loops occurring within each separate unit and the other two are outer loops linking the two modeling units. The feedback mechanisms are incorporated into the constitutive relations for model parameters, i.e., the colonization and mortality rates in the logistic growth curves that are jointly determined by the state variables of all sub-systems. The co-evolution of the Tarim socio-hydrological system is then analyzed with this conceptual model to gain insights into the overall system dynamics and its sensitivity to the external drivers and internal system variables. The results show a costly pendulum swing between a balanced distribution of socio-economic and natural ecologic resources among the upper and lower reaches and a highly skewed distribution towards the upper reach. This evolution is principally driven by the attitudinal changes occurring within water resources management policies that reflect the evolving community awareness of society to concerns regarding the ecology and environment.

[Current aspects of systemic lupus erythematosus in Dakar. About 74 cases].

PubMed

Fall, S; Dia, D; Ka, E F; Diallo, S; Pouye, A; Kane, A; Niang, A; Dieng, M T; Ka, M M; Diouf, B; Ndiaye, B; Moreira, Diop T

2007-01-01

previously reported studies on systemic lupus erythematosus in Senegal were more then ten years old and reported few cases of patients. Our objectives were to update epidemiological, clinical, laboratory and evolutive aspects of systemic lupus erythematosus throughout a study of 74 patients. we conducted a retrospective study in the internal medicine and the dermatology units of the university teaching hospital Aristide Le Dantec from January 1993 to December 2002. All patients with systemic lupus erythematosus according to the ACR criteria were included. Those who didn't meet ACR criteria were excluded. we included 74 patients; their mean age was 32 years and the sex ratio 0.1 (male to female). At the entry general symptoms were constants, and cutaneous signs were found in 96% of cases, joints signs in 58.1% and renal sign in 56.8%. Haematological and immunologic abnormalities were nearly constant. All the patients received corticosteroids and in 35.71% they had in addition immunosuppressive drugs. Shorts term evolution was satisfactory. At the medium term 27.02% of the patients were lost and 10.81% of them died. currents aspects of systemic lupus erythematosus in Dakar are improved by the early diagnosis when the disease is pauci-symptomatic and by the use immunosuppressive drugs in association with corticosteroids.

Institutional pioneers in world politics: Regional institution building and the influence of the European Union.

PubMed

Lenz, Tobias; Burilkov, Alexandr

2017-09-01

What drives processes of institution building within regional international organizations? We challenge those established theories of regionalism, and of institutionalized cooperation more broadly, that treat different organizations as independent phenomena whose evolution is conditioned primarily by internal causal factors. Developing the basic premise of 'diffusion theory' - meaning that decision-making is interdependent across organizations - we argue that institutional pioneers, and specifically the European Union, shape regional institution-building processes in a number of discernible ways. We then hypothesize two pathways - active and passive - of European Union influence, and stipulate an endogenous capacity for institutional change as a key scope condition for their operation. Drawing on a new and original data set on the institutional design of 34 regional international organizations in the period from 1950 to 2010, the article finds that: (1) both the intensity of a regional international organization's structured interaction with the European Union (active influence) and the European Union's own level of delegation (passive influence) are associated with higher levels of delegation within other regional international organizations; (2) passive European Union influence exerts a larger overall substantive effect than active European Union influence does; and (3) these effects are strongest among those regional international organizations that are based on founding contracts containing open-ended commitments. These findings indicate that the creation and subsequent institutional evolution of the European Union has made a difference to the evolution of institutions in regional international organizations elsewhere, thereby suggesting that existing theories of regionalism are insufficiently able to account for processes of institution building in such contexts.

Introduction : The Fogarty International Research Ethics Education and Curriculum Development Program in Historical Context

PubMed Central

Millum, Joseph; Grady, Christine; Keusch, Gerald; Sina, Barbara

2016-01-01

In response to the increasing need for research ethics expertise in low- and middle-income countries (LMICs), the NIH’s Fogarty International Research Ethics Education and Curriculum Development Program has provided grants for the development of training programs in international research ethics for LMIC professionals since 2000. This collection of papers draws upon the combined expertise of Fogarty grantees, trainees, and other experts to assess the state of research ethics in LMICs, and the lessons learned over 12 years of international research ethics education; to assess future needs; and to chart a way forward to meet those needs. In this introductory paper we briefly sketch the evolution of research ethics as applied to LMIC research, the underpinning and evolution of the Fogarty bioethics program, and summarize key conclusions from the other papers in the collection. PMID:24384512

Introduction: the Fogarty International Research Ethics Education and Curriculum Development Program in historical context.

PubMed

Millum, Joseph; Grady, Christine; Keusch, Gerald; Sina, Barbara

2013-12-01

In response to the increasing need for research ethics expertise in low and middle income countries (LMICs), the NIH's Fogarty International Research Ethics Education and Curriculum Development Program has provided grants for the development of training programs in international research ethics for LMIC professionals since 2000. This collection of papers draws upon the combined expertise of Fogarty grantees, trainees, and other experts to assess the state of research ethics in LMICs, and the lessons learned over 12 years of international research ethics education; to assess future needs; and to chart a way forward to meet those needs. In this introductory paper we briefly sketch the evolution of research ethics as applied to LMIC research, the underpinning and evolution of the Fogarty bioethics program, and summarize key conclusions from the other papers in the collection.

The ANTOSTRAT legacy: Science collaboration and international transparency in potential marine mineral resource exploitation of Antarctica

USGS Publications Warehouse

Cooper, Alan; Barker, Peter; Barrett, Peter; Behrendt, John; Brancolini, Giuliano; Childs, Jonathan R.; Escutia, Carlota; Jokat, Wilfried; Kristoffersen, Yngve; Leitchenkov, German; Stagg, Howard; Tanahashi, Manabu; Wardell, Nigel; Webb, Peter

2009-01-01

The Antarctic Offshore Stratigraphy project (ANTOSTRAT; 1989–2002) was an extremely successful collaboration in international marine geological science that also lifted the perceived “veil of secrecy” from studies of potential exploitation of Antarctic marine mineral resources. The project laid the groundwork for circum-Antarctic seismic, drilling, and rock coring programs designed to decipher Antarctica’s tectonic, stratigraphic, and climate histories. In 2002, ANTOSTRAT evolved into the equally successful and currently active Antarctic Climate Evolution research program. The need for, and evolution of, ANTOSTRAT was based on two simple tenets within SCAR and the Antarctic Treaty: international science collaboration and open access to data. The ANTOSTRAT project may be a helpful analog for other regions of strong international science and geopolitical interests, such as the Arctic. This is the ANTOSTRAT story.

The Scientific Committee on Antarctic Research (SCAR) in the IPY 2007-2009

NASA Astrophysics Data System (ADS)

Kennicutt, M. C.; Wilson, T. J.; Summerhayes, C.

2005-05-01

The Scientific Committee on Antarctic Research (SCAR) initiates, develops, and coordinates international scientific research in the Antarctic region. SCAR is assuming a leadership position in the IPY primarily through its five major Scientific Research Programs; ACE, SALE, EBA, AGCS, and ICESTAR; which will be briefly described.Antarctic Climate Evolution (ACE) promotes the exchange of data and ideas between research groups focusing on the evolution of Antarctica's climate system and ice sheet. The program will: (1) quantitatively assess the climate and glacial history of Antarctica; (2) identify the processes which govern Antarctic change and feed back around the globe; (3) improve our ability to model past changes in Antarctica; and (4)document past change to predict future change in Antarctica. Subglacial Antarctic Lake Environments (SALE) promotes, facilitates, and champions cooperation and collaboration in the exploration and study of subglacial environments in Antarctica. SALE intends to understand the complex interplay of biological, geological, chemical, glaciological, and physical processes within subglacial lake environments through coordinated international research teams. Evolution and Biodiversity in the Antarctic (EBA) will use a suite of modern techniques and interdisciplinary approaches, to explore the evolutionary history of selected modern Antarctic biota, examine how modern biological diversity in the Antarctic influences the way present-day ecosystems function, and thereby predict how the biota may respond to future environmental change. Antarctica and the Global Climate System (AGCS) will investigate the nature of the atmospheric and oceanic linkages between the climate of the Antarctic and the rest of the Earth system, and the mechanisms involved therein. A combination of modern instrumented records of atmospheric and oceanic conditions, and the climate signals held within ice cores will be used to understand past and future climate variability and change in the Antarctic as a result of natural and anthropogenic forcings over the last 100,000 years. Interhemispheric Conjugacy Effects in Solar-Terrestrial and Aeronomy Research (ICESTAR) will study the interactions between and collective behavior of the many component parts of the Earth system, including the interaction between the natural environment and human society. Objectives include specification and prediction of the state of the system and assimilation and integration of data from disparate sources to understand the complex geospace environment.

Principal Component Analysis reveals correlation of cavities evolution and functional motions in proteins.

PubMed

Desdouits, Nathan; Nilges, Michael; Blondel, Arnaud

2015-02-01

Protein conformation has been recognized as the key feature determining biological function, as it determines the position of the essential groups specifically interacting with substrates. Hence, the shape of the cavities or grooves at the protein surface appears to drive those functions. However, only a few studies describe the geometrical evolution of protein cavities during molecular dynamics simulations (MD), usually with a crude representation. To unveil the dynamics of cavity geometry evolution, we developed an approach combining cavity detection and Principal Component Analysis (PCA). This approach was applied to four systems subjected to MD (lysozyme, sperm whale myoglobin, Dengue envelope protein and EF-CaM complex). PCA on cavities allows us to perform efficient analysis and classification of the geometry diversity explored by a cavity. Additionally, it reveals correlations between the evolutions of the cavities and structures, and can even suggest how to modify the protein conformation to induce a given cavity geometry. It also helps to perform fast and consensual clustering of conformations according to cavity geometry. Finally, using this approach, we show that both carbon monoxide (CO) location and transfer among the different xenon sites of myoglobin are correlated with few cavity evolution modes of high amplitude. This correlation illustrates the link between ligand diffusion and the dynamic network of internal cavities. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

Dentistry and internal medicine: from the focal infection theory to the periodontal medicine concept.

PubMed

Pizzo, Giuseppe; Guiglia, Rosario; Lo Russo, Lucio; Campisi, Giuseppina

2010-12-01

During past decades the relationship between dentistry and internal medicine and especially the concept of the so-called focal infection theory have long been a matter of debate. The pathogenesis of focal diseases has been classically attributed to dental pulp pathologies and periapical infections. Nonetheless, in recent years, their role is being dismissed while increasing interest is being devoted to the possible associations between periodontal infection and systemic diseases. In fact, periodontal pathogens and their products, as well as inflammatory mediators produced in periodontal tissues, might enter the bloodstream, causing systemic effects and/or contributing to systemic diseases. On the basis of this mechanism, chronic periodontitis has been suggested as a risk factor for cardiovascular diseases associated with atherosclerosis, bacterial endocarditis, diabetes mellitus, respiratory disease, preterm delivery, rheumatoid arthritis, and, recently, osteoporosis, pancreatic cancer, metabolic syndrome, renal diseases and neurodegenerative diseases such as Alzheimer's disease. Various hypotheses, including common susceptibility, systemic inflammation, direct bacterial infection and cross-reactivity, or molecular mimicry, between bacterial antigens and self-antigens, have been postulated to explain these relationships. In this scenario, the association of periodontal disease with systemic diseases has set the stage for introducing the concept of periodontal medicine. This narrative review summarizes the evolution of focal infection theory up to the current pathophysiology of periodontal disease, and presents an update on the relationships between chronic periodontitis and systemic diseases. Copyright © 2010 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.

The time-dependent density matrix renormalisation group method

NASA Astrophysics Data System (ADS)

Ma, Haibo; Luo, Zhen; Yao, Yao

2018-04-01

Substantial progress of the time-dependent density matrix renormalisation group (t-DMRG) method in the recent 15 years is reviewed in this paper. By integrating the time evolution with the sweep procedures in density matrix renormalisation group (DMRG), t-DMRG provides an efficient tool for real-time simulations of the quantum dynamics for one-dimensional (1D) or quasi-1D strongly correlated systems with a large number of degrees of freedom. In the illustrative applications, the t-DMRG approach is applied to investigate the nonadiabatic processes in realistic chemical systems, including exciton dissociation and triplet fission in polymers and molecular aggregates as well as internal conversion in pyrazine molecule.

Engaging International Students: An Analysis of the Australian Universities Quality Agency (AUQA) Reports

ERIC Educational Resources Information Center

Burdett, Jane; Crossman, Joanna

2012-01-01

Purpose: Australia has enjoyed two decades of growth in international student enrolments. This phenomenon, combined with the evolution of quality assurance policy frameworks, has stimulated interest in the social and academic experiences of international students and their educational outcomes. The Australian Universities Quality Agency's (AUQA)…

ALARIC: An algorithm for constructing arbitrarily complex initial density distributions with low particle noise for SPH/SPMHD applications

NASA Astrophysics Data System (ADS)

Vela Vela, Luis; Sanchez, Raul; Geiger, Joachim

2018-03-01

A method is presented to obtain initial conditions for Smoothed Particle Hydrodynamic (SPH) scenarios where arbitrarily complex density distributions and low particle noise are needed. Our method, named ALARIC, tampers with the evolution of the internal variables to obtain a fast and efficient profile evolution towards the desired goal. The result has very low levels of particle noise and constitutes a perfect candidate to study the equilibrium and stability properties of SPH/SPMHD systems. The method uses the iso-thermal SPH equations to calculate hydrodynamical forces under the presence of an external fictitious potential and evolves them in time with a 2nd-order symplectic integrator. The proposed method generates tailored initial conditions that perform better in many cases than those based on purely crystalline lattices, since it prevents the appearance of anisotropies.

[The evolution of the concept of self-care in the healthcare system: a narrative literature review].

PubMed

Lommi, Marzia; Matarese, Maria; Alvaro, Rosaria; Piredda, Michela; De Marinis, Maria Grazia

2015-01-01

To identify and analyze the definitions of self-care in the healthcare system in the evolution over time as well as to identify the key actors of self-care. We conducted a narrative review of the literature on the definition of self-care in the CINAHL, PubMed and ILISI databases. The searches ranged from the first year included in each database until May 2013. In addition, a secondary analysis was performed on the references of articles selected to identify additional data sources. The self-care definitions were grouped according to decades and examined in their evolution. The first self-care definitions date back to the seventies, but only in the eighties self-care has been seen as a key resource for healthcare systems. In the nineties, care activities previously considered the exclusive domain of the health professions were included in this concept; and finally over the 2000s the role of health professionals in self-care is highlighted, extending the self-care activities to the psychological, social and spiritual dimensions. Self-care activities can be carried out directly by the person upon himself, delegated to others, or performed on others. The review has showed the large body of literature published in different disciplinary and cultural fields, which has led to the proliferation of definitions and interpretations of self-care. Italy has taken part in a marginal way to the international debate. It would be useful that also Italian nurses did research to describe and understand.

Atmospheric Monitoring Strategy for Ground Testing of Closed Ecological Life Support Systems

NASA Technical Reports Server (NTRS)

Feighery, John; Cavenall, Ivan; Knight, Amanda

2004-01-01

This paper reviews the evolution and current state of atmospheric monitoring on the International Space Station to provide context from which we can imagine a more advanced and integrated system. The unique environmental hazards of human space flight are identified and categorized into groups, taking into consideration the time required for the hazard to become a threat to human health or performance. The key functions of a comprehensive monitoring strategy for a closed ecological life support system are derived from past experience and a survey of currently available technologies for monitoring air quality. Finally, a system architecture is developed incorporating the lessons learned from ISS and other analogous closed life support systems. The paper concludes by presenting recommendations on how to proceed with requirements definition and conceptual design of an air monitoring system for exploration missions.

Internal Charmonium Evolution in the Quark-Gluon Plasma

NASA Astrophysics Data System (ADS)

Chen, Baoyi; Du, Xiaojian; Rapp, Ralf

2017-08-01

We employ a time-dependent Schrödinger equation to study the evolution of a c c ‾ dipole in a quark-gluon plasma (QGP). Medium effects on the heavy-quark potential in the QGP are found to significantly affect the timescales of the internal evolution of the dipole. Color-screening can enhance the overlap of the expanding wavepackage with excited states at high temperature, while it is reduced at lower temperatures where the dipole favors the formation of the charmonium ground state. We investigate the consequences of this mechanism on the double ratio of charmonium nuclear modification factors, RAAψ (2 S) /RAAJ/ψ, in heavy-ion collisions. The impact of the transition mechanisms on this ratio turns out to be rather sensitive to the attractive strength of the potential, and to its temperature dependence.

Innovation in Extraterrestrial Service Systems - A Challenge for Service Science

NASA Technical Reports Server (NTRS)

Bergner, David

2010-01-01

This presentation was prepared at the invitation of Professor Yukio Ohsawa, Department of Systems Innovation, School of Engineering, The University of Tokyo, for delivery at the International Workshop on Innovating Service Systems, sponsored by the Japanese Society of Artificial Intelligence (JSAI) as part of the JSAI Internation Symposium on AI, 2010. It offers several challenges for Service Science and Service Innovation. the goal of the presentation is to stimulate thinking about how service systems viII evolve in the future, as human society advances from its terrestrial base toward a permanent presence in space. First we will consider the complexity of the International Space Station (ISS) as it is today, with particular emphasis of its research facilities, and focus on a current challenge - to maximize the utilization of ISS research facilities for the benefit of society. After briefly reviewing the basic principles of Service Science, we will discuss the potential application of Service Innovation methodology to this challenge. Then we viII consider how game-changing technologies - in particular Synthetic Biology - could accelerate the pace of sociocultural evolution and consequently, the progression of human society into space. We will use this provocative vision to advance thinking about how the emerging field of Service Science, Management, and Engineering (SSME) might help us anticipate and better handle the challenges of this inevitable evolutionary process.

Flight Planning for the International Space Station-Levitation Observation of Dendrite Evolution in Steel Ternary Alloy Rapid Solidification

NASA Technical Reports Server (NTRS)

Flemings, M. C.; Matson, D. M.; Loser, W.; Hyers, R. W.; Rogers, J. R.; Curreri, Peter A. (Technical Monitor)

2002-01-01

The paper is an overview of the status and science for the LODESTARS research project. The program is aimed at understanding how melt convection influences phase selection and the evolution of rapid solidification microstructures

Optimization of macropore evolution towards high photocatalytic activity enhancement in meso/macro porous Anatase TiO2

NASA Astrophysics Data System (ADS)

Nair, Radhika V.; Gayathri, P. K.; Siva Gummaluri, Venkata; Vijayan, C.

2017-01-01

We report on an optimization strategy for macro pore evolution leading to the design of highly photocatalytic 3D hierarchical meso/macroporous TiO2 via much simpler, faster and cost effective synthesis scheme. Meso/macro porous TiO2 is an excellent candidate material for photocatalytic applications owing to the availability of internal surfaces as active sites for redox reactions. The current research scenario focuses on the design of highly efficient photocatalytic systems as well as rapid, facile and cost effective methods of synthesis and optimization of parameters. The present report is on the gradual evolution of macropores in anatase TiO2 by the effective control of pH of the solvent, reaction time, temperature, solvent ratio and reactant concentration via a facile hydrothermal method in this regard. 3D hierarchical macroporous structures are obtained at pH 7 within a comparatively short reaction time of 5 h and demonstrated to be highly photocatalytic (with rate constant four times that of P25 nanoparticles) through photodegradation of Rhodamine B dye.

Internal and environmental secular evolution of disk galaxies

NASA Astrophysics Data System (ADS)

Kormendy, John

2015-03-01

This Special Session is devoted to the secular evolution of disk galaxies. Here `secular' means `slow' i.e., evolution on time scales that are generally much longer than the galaxy crossing or rotation time. Internal and environmentally driven evolution both are covered. I am indebted to Albert Bosma for reminding me at the 2011 Canary Islands Winter School on Secular Evolution that our subject first appeared in print in a comment made by Ivan King (1977) in his introductory talk at the Yale University meeting on The Evolution of Galaxies and Stellar Populations: `John Kormendy would like us to consider the possibility that a galaxy can interact with itself.. . . I'm not at all convinced, but John can show you some interesting pictures.' Two of the earliest papers that followed were Kormendy (1979a, b); the first discusses the interaction of galaxy components with each other, and the second studies these phenomena in the context of a morphological survey of barred galaxies. The earliest modeling paper that we still use regularly is Combes & Sanders (1981), which introduces the now well known idea that box-shaped bulges in edge-on galaxies are side-on, vertically thickened bars. It is gratifying to see how this subject has grown since that time. Hundreds of papers have been written, and the topic features prominently at many meetings (e.g., Block et al. 2004; Falcoń-Barroso & Knapen 2012, and this Special Session). My talk here introduces both internal and environmental secular evolution; a brief abstract follows. My Canary Islands Winter School review covers both subjects in more detail (Kormendy 2012). Kormendy & Kennicutt (2004) is a comprehensive review of internal secular evolution, and Kormendy & Bender (2012) covers environmental evolution. Both of these subject make significant progress at this meeting. Secular evolution happens because self-gravitating systems evolve toward the most tightly bound configuration that is reachable by the evolution processes that are available to them. They do this by spreading - the inner parts shrink while the outer parts expand. Significant changes happen only if some process efficiently transports energy or angular momentum outward. The consequences are very general: evolution by spreading happens in stars, star clusters, protostellar and protoplanetary disks, black hole accretion disks and galaxy disks. This meeting is about disk galaxies, so the evolution most often involves the redistribution of angular momentum. We now have a good heuristic understanding of how nonaxisymmetric structures rearrange disk gas into outer rings, inner rings and stuff dumped onto the center. Numerical simulations reproduce observed morphologies very well. Gas that is transported to small radii reaches high densities that are seen in CO observations. Star formation rates measured (e.g.) in the mid-infrared show that many barred and oval galaxies grow, on timescales of a few Gyr, dense central `pseudobulges' that are frequently mistaken for classical (elliptical-galaxy-like) bulges but that were grown slowly out of the disk (not made rapidly by major mergers). Our resulting picture of secular evolution accounts for the richness observed in morphological classification schemes such as those of de Vaucouleurs (1959) and Sandage (1961). State-of-the art morphology discussions include the de Vaucouleurs Atlas of Galaxies (Buta et al. 2007) and Buta (2012, 2013). Pseudobulges as disk-grown alternatives to merger-built classical bulges are important because they impact many aspects of our understanding of galaxy evolution. For example, they are observed to contain supermassive black holes (BHs), but they do not show the well known, tight correlations between BH mass and host properties (Kormendy et al. 2011). We can distinguish between classical and pseudo bulges because the latter retain a `memory' of their disky origin. That is, they have one or more characteristics of disks: (1) flatter shapes than those of classical bulges, (2) correspondingly large ratios of ordered to random velocities, (3) small velocity dispersions σ with respect to the Faber-Jackson correlation between σ and bulge luminosity, (4) spiral structure or nuclear bars in the `bulge' part of the light profile, (5) nearly exponential brightness profiles and (6) starbursts. None of the above classification criteria are 100% reliable. Published disagreements on (pseudo)bulge classifications usually result from the use of diffferent criteria. It is very important to use as many classification criteria as possible. When two or more criteria are used, the probability of misclassification becomes very small. I also review environmental secular evolution - the transformation of gas-rich, star-forming spiral and irregular galaxies into gas-poor, `red and dead' S0 and spheroidal (`Sph') galaxies. I show that Sph galaxies such as NGC 205 and Draco are not the low-luminosity end of the structural sequence (the `fundamental plane') of elliptical galaxies. Instead, Sph galaxies have structural parameters like those of low-luminosity S+Im galaxies. Spheroidals are continuous in their structural parameters with the disks of S0 galaxies. They are bulgeless S0s. S+Im -> S0+Sph transformation involves a variety of internal (supernova-driven baryon ejection) and environmental processes (e.g., ram-pressure gas stripping, harassment, and starvation). Improved evidence for galaxy transformation is presented in several papers at this meeting.

Cellular packing, mechanical stress and the evolution of multicellularity

NASA Astrophysics Data System (ADS)

Jacobeen, Shane; Pentz, Jennifer T.; Graba, Elyes C.; Brandys, Colin G.; Ratcliff, William C.; Yunker, Peter J.

2018-03-01

The evolution of multicellularity set the stage for sustained increases in organismal complexity1-5. However, a fundamental aspect of this transition remains largely unknown: how do simple clusters of cells evolve increased size when confronted by forces capable of breaking intracellular bonds? Here we show that multicellular snowflake yeast clusters6-8 fracture due to crowding-induced mechanical stress. Over seven weeks ( 291 generations) of daily selection for large size, snowflake clusters evolve to increase their radius 1.7-fold by reducing the accumulation of internal stress. During this period, cells within the clusters evolve to be more elongated, concomitant with a decrease in the cellular volume fraction of the clusters. The associated increase in free space reduces the internal stress caused by cellular growth, thus delaying fracture and increasing cluster size. This work demonstrates how readily natural selection finds simple, physical solutions to spatial constraints that limit the evolution of group size—a fundamental step in the evolution of multicellularity.

Trade-Off or Convergence? The Role of Food Security in the Evolution of Food Discourse in Italy

ERIC Educational Resources Information Center

Brunori, Gianluca; Malandrin, Vanessa; Rossi, Adanella

2013-01-01

In this paper we analyse the role that "food security" has played in the evolution of the food discourse in Italy, a country with a strong and internationally recognized food culture. We identify three phases of this evolution: in the first phase, from the end of the Second World War to the end of the 1980s, the "modernization"…

The Development of a Virtual Company to Support the Reengineering of the NASA/Goddard Hubble Space Telescope Control Center System

NASA Technical Reports Server (NTRS)

Lehtonen, Ken

1999-01-01

This is a report to the Third Annual International Virtual Company Conference, on The Development of a Virtual Company to Support the Reengineering of the NASA/Goddard Hubble Space Telescope (HST) Control Center System. It begins with a HST Science "Commercial": Brief Tour of Our Universe showing various pictures taken from the Hubble Space Telescope. The presentation then reviews the project background and goals. Evolution of the Control Center System ("CCS Inc.") is then reviewed. Topics of Interest to "virtual companies" are reviewed: (1) "How To Choose A Team" (2) "Organizational Model" (3) "The Human Component" (4) "'Virtual Trust' Among Teaming Companies" (5) "Unique Challenges to Working Horizontally" (6) "The Cultural Impact" (7) "Lessons Learned".

Hybrid Semiclassical Theory of Quantum Quenches in One-Dimensional Systems

NASA Astrophysics Data System (ADS)

Moca, Cǎtǎlin Paşcu; Kormos, Márton; Zaránd, Gergely

2017-09-01

We develop a hybrid semiclassical method to study the time evolution of one-dimensional quantum systems in and out of equilibrium. Our method handles internal degrees of freedom completely quantum mechanically by a modified time-evolving block decimation method while treating orbital quasiparticle motion classically. We can follow dynamics up to time scales well beyond the reach of standard numerical methods to observe the crossover between preequilibrated and locally phase equilibrated states. As an application, we investigate the quench dynamics and phase fluctuations of a pair of tunnel-coupled one-dimensional Bose condensates. We demonstrate the emergence of soliton-collision-induced phase propagation, soliton-entropy production, and multistep thermalization. Our method can be applied to a wide range of gapped one-dimensional systems.

Analysis of competition between transformation pathways in the functioning of biotic abstract dual automata.

PubMed

Popa, Radu; Cimpoiasu, Vily M

2013-05-01

Properties of avenues of transformation and their mutualism with forms of organization in dynamic systems are essential for understanding the evolution of prebiotic order. We have analyzed competition between two avenues of transformation in an A↔B system, using the simulation approach called BiADA (Biotic Abstract Dual Automata). We discuss means of avoiding common pitfalls of abstract system modeling and benefits of BiADA-based simulations. We describe the effect of the availability of free energy, energy sink magnitude, and autocatalysis on the evolution of energy flux and order in the system. Results indicate that prebiotic competition between avenues of transformation was more stringent in energy-limited environments. We predict that in such conditions the efficiency of autocatalysis during competition between alternative system states will increase for systems with forms of organization having short half-lives and thus information that is time-sensitive to energy starvation. Our results also offer a potential solution to Manfred Eigen's error catastrophe dilemma. In the conditions discussed above, the exponential growth of quasi species is curbed through the removal of less competitive "genetic" variants via energy starvation. We propose that one of the most important achievements (and selective edges) of a dynamic network during competition in energy-limited or energy-variable environments was the capacity to correlate the internal energy flux and the need for free energy with the availability of free energy in the environment.

New perspectives on the accretion and internal evolution of Venus

NASA Astrophysics Data System (ADS)

O'Rourke, J. G.

2017-12-01

Dichotomous conditions on Earth and Venus present one of the most compelling mysteries in our Solar System. Ongoing debate centers on how the internal dynamics of Venus have shaped its atmospheric composition, surface features, and even habitability over geologic time. In particular, Venus may have resembled Earth for billions of years before suffering catastrophic transformation, or perhaps some accretionary process set these twin planets on divergent paths from the beginning. Unfortunately, the limited quality of decades-old data—particularly the low resolution of radar imagery and global topography from NASA's Magellan mission—harms our ability to draw definite conclusions. But some progress is possible given recent advances in modeling techniques and improved topography derived from stereo images that are available for roughly twenty percent of the surface. Here I present simulations of the interior evolution of Venus consistent with all available constraints and, more importantly, identify future measurements that would dramatically narrow the range of acceptable scenarios. Obtaining high-resolution imagery and topography, along with any information about the temporal history of a magnetic field, is extremely important. Deformation of geologic features constrains the surface heat flow and lithospheric rheology during their formation. Determining whether craters with radar-dark floors (which comprise 80% of the population) are actually embayed by lava flows would finally settle the controversy over catastrophic versus equilibrium resurfacing. If the core of Venus has completely solidified, then the lack of an internally generated magnetic field today is unsurprising. We might expect dynamo action in the past since relatively high mantle temperatures may increase the rate of core cooling—unless a lack of giant impacts during accretion permitted chemical stratification that resists convection. In any case, uncertainty about our celestial cousin reveals a general ignorance of fundamental processes governing planetary evolution and demands renewed effort to gather new observations.

Model of fluid flow and internal erosion of a porous fragile medium

NASA Astrophysics Data System (ADS)

Kudrolli, Arshad; Clotet, Xavier

2016-11-01

We discuss the internal erosion and transport of particles leading to heterogeneity and channelization of a porous granular bed driven by fluid flow by introducing a model experimental system which enables direct visualization of the evolution of porosity from the single particle up to the system scale. Further, we develop a hybrid hydrodynamic-statistical model to understand the main ingredients needed to simulate our observations. A uniqueness of our study is the close coupling of the experiments and simulations with control parameters used in the simulations derived from the experiments. Understanding this system is of fundamental importance to a number of geophysical processes, and in the extraction of hydrocarbons in the subsurface including the deposition of proppants used in hydraulic fracturing. We provide clear evidence for the importance of curvature of the interface between high and low porosity regions in determining the flux rate needed for erosion and the spatial locations where channels grow. This material is based upon work supported by the U.S. Department of Energy Office of Science, Office of Basic Energy Sciences program under DE-SC0010274.

Institutional pioneers in world politics: Regional institution building and the influence of the European Union

PubMed Central

Lenz, Tobias; Burilkov, Alexandr

2016-01-01

What drives processes of institution building within regional international organizations? We challenge those established theories of regionalism, and of institutionalized cooperation more broadly, that treat different organizations as independent phenomena whose evolution is conditioned primarily by internal causal factors. Developing the basic premise of ‘diffusion theory’ — meaning that decision-making is interdependent across organizations — we argue that institutional pioneers, and specifically the European Union, shape regional institution-building processes in a number of discernible ways. We then hypothesize two pathways — active and passive — of European Union influence, and stipulate an endogenous capacity for institutional change as a key scope condition for their operation. Drawing on a new and original data set on the institutional design of 34 regional international organizations in the period from 1950 to 2010, the article finds that: (1) both the intensity of a regional international organization’s structured interaction with the European Union (active influence) and the European Union’s own level of delegation (passive influence) are associated with higher levels of delegation within other regional international organizations; (2) passive European Union influence exerts a larger overall substantive effect than active European Union influence does; and (3) these effects are strongest among those regional international organizations that are based on founding contracts containing open-ended commitments. These findings indicate that the creation and subsequent institutional evolution of the European Union has made a difference to the evolution of institutions in regional international organizations elsewhere, thereby suggesting that existing theories of regionalism are insufficiently able to account for processes of institution building in such contexts. PMID:29400350

The evolution of blood pressure and the rise of mankind.

PubMed

Schulte, Kevin; Kunter, Uta; Moeller, Marcus J

2015-05-01

Why is it that only human beings continuously perform acts of heroism? Looking back at our evolutionary history can offer us some potentially useful insight. This review highlights some of the major steps in our evolution-more specifically, the evolution of high blood pressure. When we were fish, the first kidney was developed to create a standardized internal 'milieu' preserving the primordial sea within us. When we conquered land as amphibians, the evolution of the lung required a low systemic blood pressure, which explains why early land vertebrates (amphibians, reptiles) are such low performers. Gaining independence from water required the evolution of an impermeable skin and a water-retaining kidney. The latter was accomplished twice with two different solutions in the two major branches of vertebrate evolution: mammals excrete nitrogenous waste products as urea, which can be utilized by the kidney as an osmotic agent to produce more concentrated urine. Dinosaurs and birds have a distinct nitrogen metabolism and excrete nitrogen as water-insoluble uric acid-therefore, their kidneys cannot use urea to concentrate as well. Instead, some birds have developed the capability to reabsorb water from their cloacae. The convergent development of a separate small circulation of the lung in mammals and birds allowed for the evolution of 'high blood-pressure animals' with better capillarization of the peripheral tissues allowing high endurance performance. Finally, we investigate why mankind outperforms any other mammal on earth and why, to this day, we continue to perform acts of heroism on our eternal quest for personal bliss. © The Author 2014. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.

Seismic patterns and migration history of submarine fan channels in deep-water area, Niger Delta, West Africa

NASA Astrophysics Data System (ADS)

Zhang, Guotao; Zhang, Shangfeng; Li, Yuan

2015-04-01

The channels of deep-water submarine fan under Niger delta slope are characterized by large dimensions special deposition positions and complex formation processes, its geographical location and sedimentary environment also hinder the research and exploration development. According to the strata slicing, RMS amplitude attribute and other techniques, we exhibit the platforms patterns of channels at different period, and based on the analysis of internal architecture and deformation history of channel-leveed systems, migration and evolution process of channel systems could be understood accurately. A great quantity of isolated channels develop in middle Miocene and aggrading streams in late Miocene, which generating because of large scale of turbidity caused by the drop of second order sea-level, which characterized by vertical accretion at smooth channel, while vertical accretion and lateral migration at bend. Evolution of channel systems can be divided into three stages: the initial erosion, erosion and filling alternately, and abandoned stage. With these three stages, the sinuosity of channel change from moderate to high, then decrease. Incision and filling of channels, being during the three development phases, is the driving force of meander-loops migration, which promote three kinds of migration patterns: lateral, down-system and combination migration. The research provides theoretical basis for high-precision prediction and evaluation of deep-water reservoir.

Computational power and generative capacity of genetic systems.

PubMed

Igamberdiev, Abir U; Shklovskiy-Kordi, Nikita E

2016-01-01

Semiotic characteristics of genetic sequences are based on the general principles of linguistics formulated by Ferdinand de Saussure, such as the arbitrariness of sign and the linear nature of the signifier. Besides these semiotic features that are attributable to the basic structure of the genetic code, the principle of generativity of genetic language is important for understanding biological transformations. The problem of generativity in genetic systems arises to a possibility of different interpretations of genetic texts, and corresponds to what Alexander von Humboldt called "the infinite use of finite means". These interpretations appear in the individual development as the spatiotemporal sequences of realizations of different textual meanings, as well as the emergence of hyper-textual statements about the text itself, which underlies the process of biological evolution. These interpretations are accomplished at the level of the readout of genetic texts by the structures defined by Efim Liberman as "the molecular computer of cell", which includes DNA, RNA and the corresponding enzymes operating with molecular addresses. The molecular computer performs physically manifested mathematical operations and possesses both reading and writing capacities. Generativity paradoxically resides in the biological computational system as a possibility to incorporate meta-statements about the system, and thus establishes the internal capacity for its evolution. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Lunar and Planetary Science XXXV: Special Session: Oxygen in the Solar System, I

NASA Technical Reports Server (NTRS)

2004-01-01

The Special Session: Oxygen in the Solar System, I, included the following reports:Oxygen in the Solar System: Origins of Isotopic and Redox Complexity; The Origin of Oxygen Isotope Variations in the Early Solar System; Solar and Solar-Wind Oxygen Isotopes and the Genesis Mission; Solar 18O/17O and the Setting for Solar Birth; Oxygen Isotopes in Early Solar System Materials: A Perspective Based on Microbeam Analyses of Chondrules from CV Carbonaceous Chondrites; Insight into Primordial Solar System Oxygen Reservoirs from Returned Cometary Samples; Tracing Meteorites to Their Sources Through Asteroid Spectroscopy; Redox Conditions Among the Terrestrial Planets; Redox Complexity in Martian Meteorites: Implications for Oxygen in the Terrestrial Planets; Implications of Sulfur Isotopes for the Evolution of Atmospheric Oxygen; Oxygen in the Outer Solar System; and On the Oxidation States of the Galilean Satellites: Implications for Internal Structures.

The Moon: Keystone to Understanding Planetary Geological Processes and History

NASA Technical Reports Server (NTRS)

2002-01-01

Extensive and intensive exploration of the Earth's Moon by astronauts and an international array of automated spacecraft has provided an unequaled data set that has provided deep insight into geology, geochemistry, mineralogy, petrology, chronology, geophysics and internal structure. This level of insight is unequaled except for Earth. Analysis of these data sets over the last 35 years has proven fundamental to understanding planetary surface processes and evolution, and is essential to linking surface processes with internal and thermal evolution. Much of the understanding that we presently have of other terrestrial planets and outer planet satellites derives from the foundation of these data. On the basis of these data, the Moon is a laboratory for understanding of planetary processes and a keystone for providing evolutionary perspective. Important comparative planetology issues being addressed by lunar studies include impact cratering, magmatic activity and tectonism. Future planetary exploration plans should keep in mind the importance of further lunar exploration in continuing to build solid underpinnings in this keystone to planetary evolution. Examples of these insights and applications to other planets are cited.

The evolution of bacterial cell size: the internal diffusion-constraint hypothesis.

PubMed

Gallet, Romain; Violle, Cyrille; Fromin, Nathalie; Jabbour-Zahab, Roula; Enquist, Brian J; Lenormand, Thomas

2017-07-01

Size is one of the most important biological traits influencing organismal ecology and evolution. However, we know little about the drivers of body size evolution in unicellulars. A long-term evolution experiment (Lenski's LTEE) in which Escherichia coli adapts to a simple glucose medium has shown that not only the growth rate and the fitness of the bacterium increase over time but also its cell size. This increase in size contradicts prominent 'external diffusion' theory (EDC) predicting that cell size should have evolved toward smaller cells. Among several scenarios, we propose and test an alternative 'internal diffusion-constraint' (IDC) hypothesis for cell size evolution. A change in cell volume affects metabolite concentrations in the cytoplasm. The IDC states that a higher metabolism can be achieved by a reduction in the molecular traffic time inside of the cell, by increasing its volume. To test this hypothesis, we studied a population from the LTEE. We show that bigger cells with greater growth and CO 2 production rates and lower mass-to-volume ratio were selected over time in the LTEE. These results are consistent with the IDC hypothesis. This novel hypothesis offers a promising approach for understanding the evolutionary constraints on cell size.

The evolution of the cancer formulary review in Canada: Can centralization improve the use of economic evaluation?

PubMed

Wranik, W Dominika; Gambold, Liesl; Hanson, Natasha; Levy, Adrian

2017-04-01

Public reimbursement of drugs is a costly proposition for health care systems. Decisions to add drugs to the public formulary are often guided by review processes and committees. The evolution of the formulary review process in Canada's publicly funded health system is characterized by increased centralization and systematization. In the past, the review of evidence and recommendation was conducted at the regional level, but was replaced with the pan-Canadian Oncology Drug Review in 2011. We assess the extent to which centralization and systematization of the review process have responded to past challenges, focusing on the use of economic evaluation in the process. Past challenges with economic evaluation experienced by regionalized review committees were identified from literature and qualitative data collected in the province of Nova Scotia. We categorize these using a typology with a macro-, meso, and micro-level hierarchy, which provides a useful framework for understanding at which level change is required, and who has the authority to influence change. Using grounded theory methods, we identify approaches used by Nova Scotia past committee members to compensate for perceived shortcomings of the process. These include an undue reliance on other committee members, on the multidisciplinarity of the committee, and on past decisions. Using a policy analysis approach, we argue that centralization and systematization of the review process only partially address the shortcomings of the previous regionalized process. Lessons from Canada can inform policy discussions across all health systems, where similar challenges with the formulary review process have been identified. © 2016 The Authors. The International Journal of Health Planning and Management published by John Wiley & Sons Ltd. © 2016 The Authors. The International Journal of Health Planning and Management published by John Wiley & Sons Ltd.

A New Framework For The Evolution of Terrestrial Planets: Bi-stability, Stochastic Effects, and the Non-Uniqueness of Tectonic States

NASA Astrophysics Data System (ADS)

Weller, M. B.; Lenardic, A.

2017-12-01

Of all the Solar System bodies, the Earth is the only one for which significant observation and constraints are accessible such that they can be used to discriminate between competing models of Earth's tectonic evolution. Therefore, it is a natural tendency to use these observations to inform more general models of planetary evolution. Yet, our understating of Earth's evolution is far from complete. Geodynamic and geochemical evidence suggests that plate tectonics may not have operated on the early Earth, with both the timing of its onset and the length of its activity far from certain. In recent years, the potential of tectonic bi-stability (multiple stable, energetically allowed solutions) has been shown to be dynamically viable, both from analytical analysis and through numeric experiments in two and three dimensions. The indication is that multiple tectonic modes may operate on a single planetary body at different times within its temporal evolution. Further, there exists the potential that feedback mechanisms between the internal dynamics and surface processes (e.g., surface temperature changes driven by long term climate evolution), acting at different thermal evolution times, can cause terrestrial worlds to alternate between multiple tectonic states over giga-year timescales. Implied here is that terrestrial planets have the potential to migrate through tectonic regimes at similar `thermal evolutionary times' - points were planets have a similar bulk mantle temperature and energies -, but at very different `temporal times' - time since planetary formation. It can then be shown that identical planets at similar stages of their evolution may exhibit different tectonic regimes due to random fluctuations. A new framework of planetary evolution that moves toward probabilistic arguments based on general physical principals, as opposed to particular rheologies, and incorporates the potential of tectonic regime transitions and multiple tectonics states being viable at equivalent physical and chemical conditions, will be discussed.

Tour of a labyrinth: exploring the vertebrate nose.

PubMed

Van Valkenburgh, Blaire; Smith, Timothy D; Craven, Brent A

2014-11-01

This special issue of The Anatomical Record is the outcome of a symposium entitled "Inside the Vertebrate Nose: Evolution, Structure and Function." The skeletal framework of the nasal cavity is a complicated structure that often houses sinuses and comprises an internal skeleton of bone or cartilage that can vary greatly in architecture among species. The nose serves multiple functions, including olfaction and respiratory air-conditioning, and its morphology is constrained by evolution, development, and conflicting demands on cranial space, such as enlarged orbits. The nasal cavity of vertebrates has received much more attention in the last decade due to the emergence of nondestructive methods that allow improved visualization of the internal anatomy of the skull, such as high-resolution x-ray computed tomography and magnetic resonance imaging. The 17 articles included here represent a broad range of investigators, from paleontologists to engineers, who approach the nose from different perspectives. Key topics include the evolution and development of the nose, its comparative anatomy and function, and airflow through the nasal cavity of individual species. In addition, this special issue includes review articles on anatomical reduction of the olfactory apparatus in both cetaceans and primates (the vomeronasal system), as well as the molecular biology of olfaction in vertebrates. Together these articles provide an expansive summary of our current understanding of vertebrate nasal anatomy and function. In this introduction, we provide background information and an overview of each of the three primary topics, and place each article within the context of previous research and the major challenges that lie ahead. © 2014 Wiley Periodicals, Inc.

Circumstellar Disks and Outflows in Turbulent Molecular Cloud Cores: Possible Formation Mechanism for Misaligned Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matsumoto, Tomoaki; Machida, Masahiro N.; Inutsuka, Shu-ichiro, E-mail: matsu@hosei.ac.jp

2017-04-10

We investigate the formation of circumstellar disks and outflows subsequent to the collapse of molecular cloud cores with the magnetic field and turbulence. Numerical simulations are performed by using an adaptive mesh refinement to follow the evolution up to ∼1000 years after the formation of a protostar. In the simulations, circumstellar disks are formed around the protostars; those in magnetized models are considerably smaller than those in nonmagnetized models, but their size increases with time. The models with stronger magnetic fields tend to produce smaller disks. During evolution in the magnetized models, the mass ratios of a disk to amore » protostar is approximately constant at ∼1%–10%. The circumstellar disks are aligned according to their angular momentum, and the outflows accelerate along the magnetic field on the 10–100 au scale; this produces a disk that is misaligned with the outflow. The outflows are classified into two types: a magnetocentrifugal wind and a spiral flow. In the latter, because of the geometry, the axis of rotation is misaligned with the magnetic field. The magnetic field has an internal structure in the cloud cores, which also causes misalignment between the outflows and the magnetic field on the scale of the cloud core. The distribution of the angular momentum vectors in a core also has a non-monotonic internal structure. This should create a time-dependent accretion of angular momenta onto the circumstellar disk. Therefore, the circumstellar disks are expected to change their orientation as well as their sizes in the long-term evolutions.« less

Thermal Evolution and Crystallisation Regimes of the Martian Core

NASA Astrophysics Data System (ADS)

Davies, C. J.; Pommier, A.

2015-12-01

Though it is accepted that Mars has a sulfur-rich metallic core, its chemical and physical state as well as its time-evolution are still unconstrained and debated. Several lines of evidence indicate that an internal magnetic field was once generated on Mars and that this field decayed around 3.7-4.0 Gyrs ago. The standard model assumes that this field was produced by a thermal (and perhaps chemical) dynamo operating in the Martian core. We use this information to construct parameterized models of the Martian dynamo in order to place constraints on the thermochemical evolution of the Martian core, with particular focus on its crystallization regime. Considered compositions are in the FeS system, with S content ranging from ~10 and 16 wt%. Core radius, density and CMB pressure are varied within the errors provided by recent internal structure models that satisfy the available geodetic constraints (planetary mass, moment of inertia and tidal Love number). We also vary the melting curve and adiabat, CMB heat flow and thermal conductivity. Successful models are those that match the dynamo cessation time and fall within the bounds on present-day CMB temperature. The resulting suite of over 500 models suggest three possible crystallization regimes: growth of a solid inner core starting at the center of the planet; freezing and precipitation of solid iron (Fe- snow) from the core-mantle boundary (CMB); and freezing that begins midway through the core. Our analysis focuses on the effects of core properties that are expected to be constrained during the forthcoming Insight mission.

Interface-Driven Phenomena in Solids: Thermodynamics, Kinetics and Chemistry

DOE PAGES

Abdeljawad, Fadi; Foiles, Stephen M.

2016-05-04

The study of materials interfaces dates back over a century. In solid systems and from an engineering perspective, free surfaces and internal (grain and/or phase) boundaries influence a wide range of properties, such as thermal, electrical and optical transport, and mechanical ones. The properties and the role of interfaces has been discussed extensively in various reviews such as by Sutton and Balluffi. As the characteristic feature size of a materials system (i.e., grain size) is decreased to the nanometer scale, interface-driven physics is expected to dominate due to the increased density of such planar defects. Moreover, interfacial attributes, thermodynamics, andmore » mobility play a key role in phase transformations, such as solidification dynamics and structural transitions in solids, and in homogenization and microstructural evolution processes, such as grain growth, coarsening, and recrystallization. In summary, the set of articles published in this special topic titled: “Interface-Driven Phenomena in Solids: Thermodynamics, Kinetics and Chemistry” covers topics related to microstructure evolution, segregation/adsorption phenomena and interface interactions with other materials defects.« less

Interface-Driven Phenomena in Solids: Thermodynamics, Kinetics and Chemistry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abdeljawad, Fadi; Foiles, Stephen M.

The study of materials interfaces dates back over a century. In solid systems and from an engineering perspective, free surfaces and internal (grain and/or phase) boundaries influence a wide range of properties, such as thermal, electrical and optical transport, and mechanical ones. The properties and the role of interfaces has been discussed extensively in various reviews such as by Sutton and Balluffi. As the characteristic feature size of a materials system (i.e., grain size) is decreased to the nanometer scale, interface-driven physics is expected to dominate due to the increased density of such planar defects. Moreover, interfacial attributes, thermodynamics, andmore » mobility play a key role in phase transformations, such as solidification dynamics and structural transitions in solids, and in homogenization and microstructural evolution processes, such as grain growth, coarsening, and recrystallization. In summary, the set of articles published in this special topic titled: “Interface-Driven Phenomena in Solids: Thermodynamics, Kinetics and Chemistry” covers topics related to microstructure evolution, segregation/adsorption phenomena and interface interactions with other materials defects.« less

The development of test beds to support the definition and evolution of the Space Station Freedom power system

NASA Technical Reports Server (NTRS)

Soeder, James F.; Frye, Robert J.; Phillips, Rudy L.

1991-01-01

Since the beginning of the Space Station Freedom Program (SSFP), the Lewis Research Center (LeRC) and the Rocketdyne Division of Rockwell International have had extensive efforts underway to develop test beds to support the definition of the detailed electrical power system design. Because of the extensive redirections that have taken place in the Space Station Freedom Program in the past several years, the test bed effort was forced to accommodate a large number of changes. A short history of these program changes and their impact on the LeRC test beds is presented to understand how the current test bed configuration has evolved. The current test objectives and the development approach for the current DC Test Bed are discussed. A description of the test bed configuration, along with its power and controller hardware and its software components, is presented. Next, the uses of the test bed during the mature design and verification phase of SSFP are examined. Finally, the uses of the test bed in operation and evolution of the SSF are addressed.

Investigation of evolution-related aspects of bacterial rhodopsins

NASA Technical Reports Server (NTRS)

1994-01-01

We have investigated evolution-related aspects of bacterial rhodopsins, the unique retinal-based energy transducing systems of halophilic archae. The approach was to describe both structural and functional aspects: the structure by sequencing genes to explore which regions are conserved, and the function by comparing proton and chloride transport in the closely related systems, bacteriorhodopsin and halorhodopsin, respectively. In the latter, we have made a good start toward the ultimate goal of separating the attributes of the general principles of retinal-based ionic pumps from those of the specific ion specificities, by determining the thermodynamics of the internal steps of the protein-mediated active transport process, as well as some of the intraprotein ion-transfer steps. Our present emphasis is on continuing to acquire the tools for studying what distinguishes proton transport from chloride transport. We consider it important, therefore, that we have been able to provide firm mathematical grounds for the kinetics analyses which underlies these studies. Our molecular biological studies have received a great boost from the expression vector for the bop gene based on a halobacterial plasmid, that we recently developed.

The development of test beds to support the definition and evolution of the Space Station Freedom power system

NASA Technical Reports Server (NTRS)

Soeder, James F.; Frye, Robert J.; Phillips, Rudy L.

1991-01-01

Since the beginning of the Space Station Freedom Program (SSFP), the NASA Lewis Research Center (LeRC) and the Rocketdyne Division of Rockwell International have had extensive efforts underway to develop testbeds to support the definition of the detailed electrical power system design. Because of the extensive redirections that have taken place in the Space Station Freedom Program in the past several years, the test bed effort was forced to accommodate a large number of changes. A short history of these program changes and their impact on the LeRC test beds is presented to understand how the current test bed configuration has evolved. The current test objectives and the development approach for the current DC test bed are discussed. A description of the test bed configuration, along with its power and controller hardware and its software components, is presented. Next, the uses of the test bed during the mature design and verification phase of SSFP are examined. Finally, the uses of the test bed in the operation and evolution of the SSF are addressed.

Deformation Microstructures Near Vickers Indentations in SNO2/SI Coated Systems

NASA Astrophysics Data System (ADS)

Daria, G.; Evghenii, H.; Olga, S.; Zinaida, D.; Iana, M.; Victor, Z.

The micromechanical properties (hardness and brittleness) of the hard-on-hard SnO2 / Si-coated system (CS) and their modification depending the on load value has been studied. A nonmonotonic changing of microhardness with load growth was detected. The brittle/plastic behavior of the rigid/hard-on-hard SnO2 / Si CS and its response to concentrated load action explains it.A specific evolution of the indentation-deformed zone vs. load value attributed to the change in the internal stress redistribution between film and substrate was detected. It results in a brittleness indentation size effect (BISE) of the SnO2 / Si CS revealed in this experiment.It was shown that the greater portion of internal stresses under indentation is concentrated in the coating layer at small loads. This fact causes a strong elastic-plastic relaxation in the film and its delamination from substrate. The increase of brittle failure in the indentation-deformed zone with a decrease of indentation load was revealed.

International collaboration on used fuel disposition crystalline rocks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Yifeng; Gardner, Payton; Kim, Geon-Young

Active participation in international R&D is crucial for achieving the UFD long-term goals of conducting “experiments to fill data needs and confirm advanced modeling approaches” (by 2015) and of having a “robust modeling and experimental basis for evaluation of multiple disposal system options” (by 2020). DOE’s Office of Nuclear Energy (NE) and its Office of Used Fuel Disposition Research and Development (UFD) have developed a strategic plan to advance cooperation with international partners. The international collaboration on the evaluation of crystalline disposal media at Sandia National Laboratories (SNL) in FY16 focused on the following four activities: (1) thermal-hydrologic-mechanical-chemical modeling singlemore » fracture evolution; (2) simulations of flow and transport in Bedrichov Tunnel, Czech Republic, (3) completion of streaming potential testing at Korean Atomic Energy Research Institute (KAERI), and (4) technical data exchange with KAERI on thermal-hydrologic-mechanical (THM) properties and specifications of bentonite buffer materials. The first two activities are part of the Development of Coupled Models and their Validation against Experiments (DECOVALEX-2015) project.« less

Internal wave damping in the East China in late summer 2014

NASA Astrophysics Data System (ADS)

Kuh Kang, Sok; Lee, Jae Hak; Park, Jae-Hun; Kim, Eun Jin; Hong, Chang Su

2016-04-01

A field measurement was carried out to observe generation, propagation and damping of the internal waves on the continental shelf around 31N in the East China Sea during September 16-27, 2014. Two trawl-resistant bottom mount ADCPs (M1, M2) were deployed along 126.5oE with 10 km apart. Over the 10 km distance the dominant frequency internal wave group with periods around 500 s is estimated to dissipate its energy by about 30%. The damping process appears to be partly related with the higher-mode evolution at the downward station M1, compared with the 1st-mode dominancy at the upstream station (M2). Our observations suggest that the damping processes of internal waves on the continental shelf of the East China Sea occur by rather complicated manners than by the simple process due to frictional decaying. This work was partially supported by KIOST projects (PE99396)and this research has been performed as collaborative research project of project No (Development of HPC-based management system againstnational scale disaster) and supported by the KOREA INSTITUTE of SCIENCE and TECHNOLOGY INFORMATION (KISTI).

The ecology and evolution of gall-forming insects.

Treesearch

Peter W. Price; William J. Mattson; Yuri N. Baranchikov

1994-01-01

This international proceedings focuses on the biology, ecology, and evolution of gall-forming insects and their uniquely specialized relationships with their host plants. The individual contributions range in scope from detailed descriptive to profoundly theoretical, synthetic studies. One underlying theme of the proceedings is the important contribution of knowledge...

Depth evolution of the Meirama pit lake, A Coruña, NW Spain

NASA Astrophysics Data System (ADS)

Delgado, Jordi; Juncosa-Rivera, Ricardo; Cereijo-Arango, José Luis; García-Morrondo, David; Muñoz-Ibáñez, Andrea; Grande-García, Elisa; Rodríguez-Cedrún, Borja

2016-04-01

The Meirama pit lake is a water mass in the process of controlled flooding that, by the end of December 2015, can be described as a steadily stratified meromictic system. The deepest portion of the lake (monimolimnion) is isolated regarding the annual mixing dynamics (December/January) of the upper water body (mixolimnion), for which the depth of mixing is restricted to a water column of 35-40 m thick. Due to the contrasting flooding history (access of groundwater at the beginning and mixed access of stream/groundwater (being dominant the stream water) the deepest portion of the lake is separated from the upper, non-mixed layer by a marked chemocline. Strictly speaking, the monimolimnion of a meromictic lake extends to the waters located beneath the mixed lake layer. In the case of the Meirama Lake the monimolimnion is internally stratified and made of two major water bodies. From hereafter the deep and upper monimolimnion will be identified as bottom and middle sections of the lake while the mixolimnion is referred to as the surface layer. The general characteristics and evolution of the Meirama Lake have been reported elsewhere. In this work we focus on a summary description of the chemical evolution of the monimolimnion of the lake based on data gathered between 2009 and 2015 from the still on-going monitoring survey. The chemical evolution of the monimolimnion of the lake differs significantly from that of the mixolimnion. In general, surface water is sensible to seasonal fluctuations due to weather conditions, rainfall and biogeochemical processes. The middle and bottom sections are not sensible, in general, to this effects and their evolution obeys to a number of internal processes. In the case of temperature we observe a nearly constant gradient increase (0.001 °C/day) in the middle and deep lake waters up to the beginning of 2012, where it remains constant. The rise in temperature is likely due to the heat provided by groundwater seepage whose temperature is above that of the lake water at the corresponding depth. Likewise, electrical conductance shows a similar constant-rate increasing rate (0.223 and 0.115 S/cm-day in the bottom and middle sections, respectively) whose origin we also associate with groundwater seepage. Based on a wide number of parameters (O2, Cl, SO4, NO3, NO2, NH4, Fe, Mn…) we observe that the monimolimnion of the lake, either in its bottom or middle layer is a rather dynamic (transient) geochemical system.

Towards high performing hospital enterprise systems: an empirical and literature based design framework

NASA Astrophysics Data System (ADS)

dos Santos Fradinho, Jorge Miguel

2014-05-01

Our understanding of enterprise systems (ES) is gradually evolving towards a sense of design which leverages multidisciplinary bodies of knowledge that may bolster hybrid research designs and together further the characterisation of ES operation and performance. This article aims to contribute towards ES design theory with its hospital enterprise systems design (HESD) framework, which reflects a rich multidisciplinary literature and two in-depth hospital empirical cases from the US and UK. In doing so it leverages systems thinking principles and traditionally disparate bodies of knowledge to bolster the theoretical evolution and foundation of ES. A total of seven core ES design elements are identified and characterised with 24 main categories and 53 subcategories. In addition, it builds on recent work which suggests that hospital enterprises are comprised of multiple internal ES configurations which may generate different levels of performance. Multiple sources of evidence were collected including electronic medical records, 54 recorded interviews, observation, and internal documents. Both in-depth cases compare and contrast higher and lower performing ES configurations. Following literal replication across in-depth cases, this article concludes that hospital performance can be improved through an enriched understanding of hospital ES design.

Representing the thermal state in time-dependent density functional theory

DOE PAGES

Modine, N. A.; Hatcher, R. M.

2015-05-28

Classical molecular dynamics (MD) provides a powerful and widely used approach to determining thermodynamic properties by integrating the classical equations of motion of a system of atoms. Time-Dependent Density Functional Theory (TDDFT) provides a powerful and increasingly useful approach to integrating the quantum equations of motion for a system of electrons. TDDFT efficiently captures the unitary evolution of a many-electron state by mapping the system into a fictitious non-interacting system. In analogy to MD, one could imagine obtaining the thermodynamic properties of an electronic system from a TDDFT simulation in which the electrons are excited from their ground state bymore » a time-dependent potential and then allowed to evolve freely in time while statistical data are captured from periodic snapshots of the system. For a variety of systems (e.g., many metals), the electrons reach an effective state of internal equilibrium due to electron-electron interactions on a time scale that is short compared to electron-phonon equilibration. During the initial time-evolution of such systems following electronic excitation, electron-phonon interactions should be negligible, and therefore, TDDFT should successfully capture the internal thermalization of the electrons. However, it is unclear how TDDFT represents the resulting thermal state. In particular, the thermal state is usually represented in quantum statistical mechanics as a mixed state, while the occupations of the TDDFT wave functions are fixed by the initial state in TDDFT. Two key questions involve (1) reformulating quantum statistical mechanics so that thermodynamic expectations can be obtained as an unweighted average over a set of many-body pure states and (2) constructing a family of non-interacting (single determinant) TDDFT states that approximate the required many-body states for the canonical ensemble. In Section II, we will address these questions by first demonstrating that thermodynamic expectations can be evaluated by averaging over certain many-body pure states, which we will call thermal states, and then constructing TDDFT states that approximate these thermal states. In Section III, we will present some numerical tests of the resulting theory, and in Section IV, we will summarize our main results and discuss some possible future directions for this work.« less

The ``Problem of the quaternary'' and the taxonomic rank of the late cenozoic in the international stratigraphic scale

NASA Astrophysics Data System (ADS)

Zubakov, V. A.

2011-02-01

An international scientific conflict has arisen around the International Stratigraphic Scale, the main document that regulates the rules of reading of geological records and, hence, concerns all Earth sciences. The matter of debate is the geological time scale of 2004, developed by the International Commission on Stratigraphy, where the Quaternary system was abandoned. This ICS decision triggered a protest among Quaternary geologists, members of INQUA, and became the subject of much controversy. This article provides a comprehensive analysis of the Quaternary problem and proposes a reasonable scientific solution that may be appropriate for both parties. The subject of Late Cenozoic geology is discussed: glaciations, human evolution, and recent deposits. In contrast to Charles Lyell's definition of the Plio-Pleistocene according to the percentage of modern mollusk species, it is defined here as a blanket formation, which is correlative to the topography and consists of mapped stratogens hosting fossils of modern biogeocenoses. Features of the description of the Plio-Pleistocene in terms of gravitational orbital tuning are considered. Four paleogeographic phases of modern environment evolution are recognized and ranked as stages: (1) The Messinian evolutionary explosion involved the appearance of many biogeocenoses and the bipedal walking of our extinct ancestors armed with sticks. It was a consequence of the Early Greenland (7.6 Ma BP) and Patagonian (6.7 Ma BP) hyperglaciations. (2) The Zanclean age is marked by climatic and hydrological but not evolutionary boundaries. (3) The appearance of the Villafranchian animal assemblage and Australopithecus, who used stones as weapon: 4.0-3.6 Ma BP. Orogeny and isolation of the Arctic Ocean changed the global climate dramatically. (4) The sexual revolution became the third evolutionary jump: the appearance of the first woman, "Eve", and the genus Homo with her: 1.9 Ma BP. According to the current view, the Plio-Pleistocene, as defined by Lyell, consists of nineteen chronozones, four stages and two series. Hence, it is a true system, Pliocene-Pleistocene = Hologene, with a GSSP at 7.6 Ma BP, complying with all rules of scientific stratigraphical subdivision, rather than the mere beginning of the archaic Quaternary pseudo system with GSSPs at 1.8 or 2.6 Ma BP

Robonaut 2 (R2) Overview

NASA Technical Reports Server (NTRS)

Diftler, Myron

2010-01-01

This slide presentation reviews the development and uses of the second robot designed to work in space. The presentation reviews the motivation for developing Robonaut, the cooperative commercial relationship with General Motors, the evolution design of Robonaut Robonaut 2 improvements over the first robonaut (R1), Robonaut 2's hand dexterity, finger impedance control, tactile system, finger haptics, arm control, strength, neck movement and head sensors, human interaction, and the controller. Also the plans for use on board the International Space Station are reviewed. The patent for the Phalange Tactile Load Cell is included.

Robotic Lunar Landers for Science and Exploration

NASA Technical Reports Server (NTRS)

Cohen, B. A.; Bassler, J. A.; Hammond, M. S.; Harris, D. W.; Hill, L. A.; Kirby, K. W.; Morse, B. J.; Mulac, B. D.; Reed, C. L. B.

2010-01-01

The Moon provides an important window into the early history of the Earth, containing information about planetary composition, magmatic evolution, surface bombardment, and exposure to the space environment. Robotic lunar landers to achieve science goals and to provide precursor technology development and site characterization are an important part of program balance within NASA s Science Mission Directorate (SMD) and Exploration Systems Mission Directorate (ESMD). A Robotic Lunar Lan-der mission complements SMD's initiatives to build a robust lunar science community through R&A lines and increases international participation in NASA's robotic exploration of the Moon.

The metrology of time.

PubMed

Arias, Elisa Felicitas

2005-09-15

Measuring time is a continuous activity, an international and restless enterprise hidden in time laboratories spread all over the planet. The Bureau International des Poids et Mesures is charged with coordinating activities for international timekeeping and it makes use of the world's capacity to produce a remarkably stable and accurate reference time-scale. Commercial atomic clocks beating the second in national laboratories can reach a stability of one part in 10(14) over a 5 day averaging time, compelling us to research the most highly performing methods of remote clock comparison. The unit of the international time-scale is the second of the International System of Units, realized with an uncertainty of the order 10(-15) by caesium fountains. Physicists in a few time laboratories are making efforts to gain one order of magnitude in the uncertainty of the realization of the second, and more refined techniques of time and frequency transfer are in development to accompany this progress. Femtosecond comb technology will most probably contribute in the near future to enhance the definition of the second with the incorporation of optical clocks. We will explain the evolution of the measuring of time, current state-of-the-art measures and future challenges.

Evolution in totally constrained models: Schrödinger vs. Heisenberg pictures

NASA Astrophysics Data System (ADS)

Olmedo, Javier

2016-06-01

We study the relation between two evolution pictures that are currently considered for totally constrained theories. Both descriptions are based on Rovelli’s evolving constants approach, where one identifies a (possibly local) degree of freedom of the system as an internal time. This method is well understood classically in several situations. The purpose of this paper is to further analyze this approach at the quantum level. Concretely, we will compare the (Schrödinger-like) picture where the physical states evolve in time with the (Heisenberg-like) picture in which one defines parametrized observables (or evolving constants of the motion). We will show that in the particular situations considered in this paper (the parametrized relativistic particle and a spatially flat homogeneous and isotropic spacetime coupled to a massless scalar field) both descriptions are equivalent. We will finally comment on possible issues and on the genericness of the equivalence between both pictures.

Question 7: Comparative Genomics and Early Cell Evolution: A Cautionary Methodological Note

NASA Astrophysics Data System (ADS)

Islas, Sara; Hernández-Morales, Ricardo; Lazcano, Antonio

2007-10-01

Inventories of the gene content of the last common ancestor (LCA), i.e., the cenancestor, include sequences that may have undergone horizontal transfer events, as well as sequences that have originated in different pre-cenancestral epochs. However, the universal distribution of highly conserved genes involved in RNA metabolism provide insights into early stages of cell evolution during which RNA played a much more conspicuous biological role, and is consistent with the hypothesis that extant living systems were preceded by an RNA/protein world. Insights into the traits of primitive entities from which the LCA evolved may be derived from the analysis of paralogous gene families, including those formed by sequences that resulted from internal elongation events. Three major types of paralogous gene families can be recognized. The importance of this grouping for understanding the traits of early cells is discussed.

Applying ecological and evolutionary theory to cancer: a long and winding road.

PubMed

Thomas, Frédéric; Fisher, Daniel; Fort, Philippe; Marie, Jean-Pierre; Daoust, Simon; Roche, Benjamin; Grunau, Christoph; Cosseau, Céline; Mitta, Guillaume; Baghdiguian, Stephen; Rousset, François; Lassus, Patrice; Assenat, Eric; Grégoire, Damien; Missé, Dorothée; Lorz, Alexander; Billy, Frédérique; Vainchenker, William; Delhommeau, François; Koscielny, Serge; Itzykson, Raphael; Tang, Ruoping; Fava, Fanny; Ballesta, Annabelle; Lepoutre, Thomas; Krasinska, Liliana; Dulic, Vjekoslav; Raynaud, Peggy; Blache, Philippe; Quittau-Prevostel, Corinne; Vignal, Emmanuel; Trauchessec, Hélène; Perthame, Benoit; Clairambault, Jean; Volpert, Vitali; Solary, Eric; Hibner, Urszula; Hochberg, Michael E

2013-01-01

Since the mid 1970s, cancer has been described as a process of Darwinian evolution, with somatic cellular selection and evolution being the fundamental processes leading to malignancy and its many manifestations (neoangiogenesis, evasion of the immune system, metastasis, and resistance to therapies). Historically, little attention has been placed on applications of evolutionary biology to understanding and controlling neoplastic progression and to prevent therapeutic failures. This is now beginning to change, and there is a growing international interest in the interface between cancer and evolutionary biology. The objective of this introduction is first to describe the basic ideas and concepts linking evolutionary biology to cancer. We then present four major fronts where the evolutionary perspective is most developed, namely laboratory and clinical models, mathematical models, databases, and techniques and assays. Finally, we discuss several of the most promising challenges and future prospects in this interdisciplinary research direction in the war against cancer.

Viral Quasispecies Evolution

PubMed Central

Sheldon, Julie; Perales, Celia

2012-01-01

Summary: Evolution of RNA viruses occurs through disequilibria of collections of closely related mutant spectra or mutant clouds termed viral quasispecies. Here we review the origin of the quasispecies concept and some biological implications of quasispecies dynamics. Two main aspects are addressed: (i) mutant clouds as reservoirs of phenotypic variants for virus adaptability and (ii) the internal interactions that are established within mutant spectra that render a virus ensemble the unit of selection. The understanding of viruses as quasispecies has led to new antiviral designs, such as lethal mutagenesis, whose aim is to drive viruses toward low fitness values with limited chances of fitness recovery. The impact of quasispecies for three salient human pathogens, human immunodeficiency virus and the hepatitis B and C viruses, is reviewed, with emphasis on antiviral treatment strategies. Finally, extensions of quasispecies to nonviral systems are briefly mentioned to emphasize the broad applicability of quasispecies theory. PMID:22688811

Intergrannular strain evolution in a zircaloy-4 alloy with Widmanstatten microstructure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clausen, Bjorn; Vogel, Sven C; Garlea, Eena

2009-01-01

A Zircaloy-4 alloy with Widmanstatten-Basketweave microstructure and random texture has been used to study the deformation systems responsible for the polycrystalline plasticity at the grain level. The evolution of internal strain and bulk texture is investigated using neutron diffraction and an elasto-plastic self-consistent (EPSC) modeling scheme. The macroscopic stress-strain behavior and intergranular (hkil-specific) strain development, parallel and perpendicular to the loading direction, were measured in-situ during uniaxial tensile loading. Then, the EPSC model was employed to simulate the experimental results. This modeling scheme accounts for the thermal anisotropy; elastic-plastic properties of the constituent grains; and activation, reorientation, and stress relaxationmore » associated with twinning. The agreement between the experiment and the model will be discussed as well as the critical resolved shear stresses (CRSS) and the hardening coefficients obtained from the model.« less

The PROCESS experiment: an astrochemistry laboratory for solid and gaseous organic samples in low-earth orbit.

PubMed

Cottin, Hervé; Guan, Yuan Yong; Noblet, Audrey; Poch, Olivier; Saiagh, Kafila; Cloix, Mégane; Macari, Frédérique; Jérome, Murielle; Coll, Patrice; Raulin, François; Stalport, Fabien; Szopa, Cyril; Bertrand, Marylène; Chabin, Annie; Westall, Frances; Chaput, Didier; Demets, René; Brack, André

2012-05-01

The PROCESS (PRebiotic Organic ChEmistry on the Space Station) experiment was part of the EXPOSE-E payload outside the European Columbus module of the International Space Station from February 2008 to August 2009. During this interval, organic samples were exposed to space conditions to simulate their evolution in various astrophysical environments. The samples used represent organic species related to the evolution of organic matter on the small bodies of the Solar System (carbonaceous asteroids and comets), the photolysis of methane in the atmosphere of Titan, and the search for organic matter at the surface of Mars. This paper describes the hardware developed for this experiment as well as the results for the glycine solid-phase samples and the gas-phase samples that were used with regard to the atmosphere of Titan. Lessons learned from this experiment are also presented for future low-Earth orbit astrochemistry investigations.

Trojan Tour and Rendezvous (TTR): A New Frontiers Mission to Explore the Origin and Evolution of the Early Solar System

NASA Astrophysics Data System (ADS)

Bell, J. F., III; Olkin, C.; Castillo, J. C.

2015-12-01

The orbital properties, compositions, and physical properties of the diverse populations of small outer solar system bodies provide a forensic map of how our solar system formed and evolved. Perhaps the most potentially diagnostic, but least explored, of those populations are the Jupiter Trojan asteroids, which orbit at ~5 AU in the L4 and L5 Lagrange points of Jupiter. More than 6200 Jupiter Trojans are presently known, but these are predicted to be only a small fraction of the 500,000 to 1 million Trojans >1 km in size. The Trojans are hypothesized to be either former Kuiper Belt Objects (KBOs) that were scattered into the inner solar system by early giant planet migration and then trapped in the 1:1 Jupiter mean motion resonance, or bodies formed near 5 AU in a much more quiescent early solar system, and then trapped at L4 and L5. The 2011 Planetary Science Decadal Survey identified important questions about the origin and evolution of the solar system that can be addressed by studying of the Trojan asteroids, including: (a) How did the giant planets and their satellite systems accrete, and is there evidence that they migrated to new orbital positions? (b) What is the relationship between large and small KBOs? Is the small population derived by impact disruption of the large one? (c) What kinds of surface evolution, radiation chemistry, and surface-atmosphere interactions occur on distant icy primitive bodies? And (d) What are the sources of asteroid groups (Trojans and Centaurs) that remain to be explored by spacecraft? The Trojan Tour and Rendezvous (TTR) is a New Frontiers-class mission designed to answer these questions, and to test hypotheses for early giant planet migration and solar system evolution. Via close flybys of a large number of these objects,, and orbital characterization of at least one large Trojan, TTR will enable the first-time exploration of this population. Our primary mission goals are to characterize the overall surface geology, geochemistry and mineralogy of these worlds; to characterize their internal structure and dynamical properties; to investigate the nature, sources and history of activity on these bodies; and to explore the diversity of the broader Trojan asteroid population.

Combating Human Trafficking: Evolution of State Legislation and the Policies of the United Kingdom and France

DTIC Science & Technology

2011-12-01

18 Pajnik, M. (2010). Media framing of trafficking. International Feminist Journal of Politics, 12(1). p. 57 19 Friesendorf, Cornelius. 2007...164 Nieuwenhuys & Pécoud, 1681. 165 Ibid., 1685. 166 Pajnik, M. (2010). Media framing of trafficking. International Feminist Journal of Politics... Media framing of trafficking. International Feminist Journal of Politics, 12(1): 54 170 Cindy Fazey, International Policy on Illicit Drug

Estimating the impact of internal climate variability on ice sheet model simulations

NASA Astrophysics Data System (ADS)

Tsai, C. Y.; Forest, C. E.; Pollard, D.

2016-12-01

Rising sea level threatens human societies and coastal habitats and melting ice sheets are a major contributor to sea level rise (SLR). Thus, understanding uncertainty of both forcing and variability within the climate system is essential for assessing long-term risk of SLR given their impact on ice sheet evolution. The predictability of polar climate is limited by uncertainties from the given forcing, the climate model response to this forcing, and the internal variability from feedbacks within the fully coupled climate system. Among those sources of uncertainty, the impact of internal climate variability on ice sheet changes has not yet been robustly assessed. Here we investigate how internal variability affects ice sheet projections using climate fields from two Community Earth System Model (CESM) large-ensemble (LE) experiments to force a three-dimensional ice sheet model. Each ensemble member in an LE experiment undergoes the same external forcings but with unique initial conditions. We find that for both LEs, 2m air temperature variability over Greenland ice sheet (GrIS) can lead to significantly different ice sheet responses. Our results show that the internal variability from two fully coupled CESM LEs can cause about 25 35 mm differences of GrIS's contribution to SLR in 2100 compared to present day (about 20% of the total change), and 100m differences of SLR in 2300. Moreover, only using ensemble-mean climate fields as the forcing in ice sheet model can significantly underestimate the melt of GrIS. As the Arctic region becomes warmer, the role of internal variability is critical given the complex nonlinear interactions between surface temperature and ice sheet. Our results demonstrate that internal variability from coupled atmosphere-ocean general circulation model can affect ice sheet simulations and the resulting sea-level projections. This study highlights an urgent need to reassess associated uncertainties of projecting ice sheet loss over the next few centuries to obtain robust estimates of the contribution of ice sheet melt to SLR.

The spread of European models of engineering education: the challenges faced in emerging countries

NASA Astrophysics Data System (ADS)

Gardelle, Linda; Cardona Gil, Emmanuel; Benguerna, Mohamed; Bolat, Altangul; Naran, Boldmaa

2017-03-01

The major European models of engineering training (the German, the British and the French model) spread throughout the world during the twentieth century. Historical heritage, cultural proximity and languages explain the open expression of faithfulness to one system in some countries. In these countries, the national standards inherited are now completed by international standards or are in direct competition with new influences. This article will attempt, through the existing literature, interviews and on-site investigations, to analyse current engineering training in some emerging countries and its relations with European models, the objective being to analyse the evolution of local systems and so the challenges and issues raised by the dissemination of European models.

Localized scleroderma: clinical spectrum and therapeutic update*

PubMed Central

Careta, Mariana Figueiroa; Romiti, Ricardo

2015-01-01

Scleroderma is a rare connective tissue disease that is manifested by cutaneous sclerosis and variable systemic involvement. Two categories of scleroderma are known: systemic sclerosis, characterized by cutaneous sclerosis and visceral involvement, and localized scleroderma or morphea which classically presents benign and self-limited evolution and is confined to the skin and/or underlying tissues. Localized scleroderma is a rare disease of unknown etiology. Recent studies show that the localized form may affect internal organs and have variable morbidity. Treatment should be started very early, before complications occur due to the high morbidity of localized scleroderma. In this review, we report the most important aspects and particularities in the treatment of patients diagnosed with localized scleroderma. PMID:25672301

Localized scleroderma: clinical spectrum and therapeutic update.

PubMed

Careta, Mariana Figueiroa; Romiti, Ricardo

2015-01-01

Scleroderma is a rare connective tissue disease that is manifested by cutaneous sclerosis and variable systemic involvement. Two categories of scleroderma are known: systemic sclerosis, characterized by cutaneous sclerosis and visceral involvement, and localized scleroderma or morphea which classically presents benign and self-limited evolution and is confined to the skin and/or underlying tissues. Localized scleroderma is a rare disease of unknown etiology. Recent studies show that the localized form may affect internal organs and have variable morbidity. Treatment should be started very early, before complications occur due to the high morbidity of localized scleroderma. In this review, we report the most important aspects and particularities in the treatment of patients diagnosed with localized scleroderma.

Massive stars in advanced evolutionary stages, and the progenitor of GW150914

NASA Astrophysics Data System (ADS)

Hamann, Wolf-Rainer; Oskinova, Lidia; Todt, Helge; Sander, Andreas; Hainich, Rainer; Shenar, Tomer; Ramachandran, Varsha

2017-11-01

The recent discovery of a gravitational wave from the merging of two black holes of about 30 solar masses each challenges our incomplete understanding of massive stars and their evolution. Critical ingredients comprise mass-loss, rotation, magnetic fields, internal mixing, and mass transfer in close binary systems. The imperfect knowledge of these factors implies large uncertainties for models of stellar populations and their feedback. In this contribution we summarize our empirical studies of Wolf-Rayet populations at different metallicities by means of modern non-LTE stellar atmosphere models, and confront these results with the predictions of stellar evolution models. At the metallicity of our Galaxy, stellar winds are probably too strong to leave remnant masses as high as ~30 M⊙, but given the still poor agreement between evolutionary tracks and observation even this conclusion is debatable. At the low metallicity of the Small Magellanic Cloud, all WN stars which are (at least now) single are consistent with evolving quasi-homogeneously. O and B-type stars, in contrast, seem to comply with standard evolutionary models without strong internal mixing. Close binaries which avoided early merging could evolve quasi-homogeneously and lead to close compact remnants of relatively high masses that merge within a Hubble time.

Convection and Dynamo Action in Ice Giant Dynamo Models with Electrical Conductivity Stratification

NASA Astrophysics Data System (ADS)

Soderlund, K. M.; Featherstone, N. A.; Heimpel, M. H.; Aurnou, J. M.

2017-12-01

Uranus and Neptune are relatively unexplored, yet critical for understanding the physical and chemical processes that control the behavior and evolution of giant planets. Because their multipolar magnetic fields, three-jet zonal winds, and extreme energy balances are distinct from other planets in our Solar System, the ice giants provide a unique opportunity to test hypotheses for internal dynamics and magnetic field generation. While it is generally agreed that dynamo action in the ionic ocean generates their magnetic fields, the mechanisms that control the morphology, strength, and evolution of the dynamos - which are likely distinct from those in the gas giants and terrestrial planets - are not well understood. We hypothesize that the dynamos and zonal winds are dynamically coupled and argue that their characteristics are a consequence of quasi-three-dimensional turbulence in their interiors. Here, we will present new dynamo simulations with an inner electrically conducting region and outer electrically insulating layer to self-consistently couple the ionic oceans and molecular envelopes of these planets. For each simulation, the magnetic field morphology and amplitude, zonal flow profile, and internal heat flux pattern will be compared against corresponding observations of Uranus and Neptune. We will also highlight how these simulations will both contribute to and benefit from a future ice giant mission.

Fluctuation relation based continuum model for thermoviscoplasticity in metals

NASA Astrophysics Data System (ADS)

Roy Chowdhury, Shubhankar; Roy, Debasish; Reddy, J. N.; Srinivasa, Arun

2016-11-01

A continuum plasticity model for metals is presented from considerations of non-equilibrium thermodynamics. Of specific interest is the application of a fluctuation relation that subsumes the second law of thermodynamics en route to deriving the evolution equations for the internal state variables. The modelling itself is accomplished in a two-temperature framework that appears naturally by considering the thermodynamic system to be composed of two weakly interacting subsystems, viz. a kinetic vibrational subsystem corresponding to the atomic lattice vibrations and a configurational subsystem of the slower degrees of freedom describing the motion of defects in a plastically deforming metal. An apparently physical nature of the present model derives upon considering the dislocation density, which characterizes the configurational subsystem, as a state variable. Unlike the usual constitutive modelling aided by the second law of thermodynamics that merely provides a guideline to select the admissible (though possibly non-unique) processes, the present formalism strictly determines the process or the evolution equations for the thermodynamic states while including the effect of fluctuations. The continuum model accommodates finite deformation and describes plastic deformation in a yield-free setup. The theory here is essentially limited to face-centered cubic metals modelled with a single dislocation density as the internal variable. Limited numerical simulations are presented with validation against relevant experimental data.

On-Orbit Propulsion and Methods of Momentum Management for the International Space Station

NASA Technical Reports Server (NTRS)

Russell, Samuel P.; Spencer, Victor; Metrocavage, Kevin; Swanson, Robert A.; Krajchovich, Mark; Beisner, Matthew; Kamath, Ulhas P.

2010-01-01

Since the first documented design of a space station in 1929, it has been a dream of many to sustain a permanent presence in space. Russia and the US spent several decades competing for a sustained human presence in low Earth orbit. In the 1980 s, Russia and the US began to openly collaborate to achieve this goal. This collaboration lead to the current design of the ISS. Continuous improvement of procedures for controlling the ISS have lead to more efficient propellant management over the years. Improved efficiency combined with the steady use of cargo vehicles has kept ISS propellant levels well above their defined thresholds in all categories. The continuing evolution of propellant and momentum management operational strategies demonstrates the capability and flexibility of the ISS propulsion system. The hard work and cooperation of the international partners and the evolving operational strategies have made the ISS safe and successful. The ISS s proven success is the foundation for the future of international cooperation for sustaining life in space.

Space Shuttle GN and C Development History and Evolution

NASA Technical Reports Server (NTRS)

Zimpfer, Douglas; Hattis, Phil; Ruppert, John; Gavert, Don

2011-01-01

Completion of the final Space Shuttle flight marks the end of a significant era in Human Spaceflight. Developed in the 1970 s, first launched in 1981, the Space Shuttle embodies many significant engineering achievements. One of these is the development and operation of the first extensive fly-by-wire human space transportation Guidance, Navigation and Control (GN&C) System. Development of the Space Shuttle GN&C represented first time inclusions of modern techniques for electronics, software, algorithms, systems and management in a complex system. Numerous technical design trades and lessons learned continue to drive current vehicle development. For example, the Space Shuttle GN&C system incorporated redundant systems, complex algorithms and flight software rigorously verified through integrated vehicle simulations and avionics integration testing techniques. Over the past thirty years, the Shuttle GN&C continued to go through a series of upgrades to improve safety, performance and to enable the complex flight operations required for assembly of the international space station. Upgrades to the GN&C ranged from the addition of nose wheel steering to modifications that extend capabilities to control of the large flexible configurations while being docked to the Space Station. This paper provides a history of the development and evolution of the Space Shuttle GN&C system. Emphasis is placed on key architecture decisions, design trades and the lessons learned for future complex space transportation system developments. Finally, some of the interesting flight operations experience is provided to inform future developers of flight experiences.

Internal structure of a barrier beach as revealed by ground penetrating radar (GPR): Chesil beach, UK

NASA Astrophysics Data System (ADS)

Bennett, Matthew R.; Cassidy, Nigel J.; Pile, Jeremy

2009-03-01

Chesil Beach (Dorset) is one of the most famous coastal landforms on the British coast. The gravel beach is over 18 km long and is separated for much of its length from land by a tidal lagoon known as The Fleet. The beach links the Isle of Portland in the east to the mainland in the west. Despite its iconic status there is little available information on its internal geometry and evolutionary history. Here we present a three-fold model for the evolution of Chesil Beach based on a series of nine ground penetrating radar (GPR) traverses located at three sites along its length at Abbotsbury, Langton Herring and at Ferry Bridge. The GPR traverses reveal a remarkably consistent picture of the internal structure of this barrier beach. The first phase of evolution involves the landward transgression of a small sand and gravel beach which closed upon the coast leading to deposition of freshwater peat between 5 and 7 k yr BP. The second evolutionary phase involves the 'bulking-out' of the beach during continued sea level rise, but in the presence of abundant gravel supplied by down-drift erosion of periglacial slope deposits. This episode of growth was associated with a series of washover fans which accumulated on the landward flank of the barrier increasing its breadth and height but without significant landward transgression of the barrier as a whole. The final phase in the evolution of Chesil Beach involves the seaward progradation of the beach crest and upper beach face associated with continued sediment abundance, but during a still-stand or slight fall in relative sea level. This phase may provide further evidence of a slight fall in relative sea level noted elsewhere along the South Coast of Britain and dated to between 1.2 and 2.4 k yr BP. Subsequently the barrier appears to have become largely inactive, except for the reworking of sediment on the beach face during storm events. The case study not only refines the evolutionary picture of Chesil Beach, but illustrates the importance of the subtle interplay between relative sea level and sediment supply in the evolution of a barrier system. In addition, it also illustrates the potential of GPR in resolving the evolutionary history of gravel-rich coastal landforms such as Chesil Beach.

Considerations of Alloy 617 Application in the Gen IV Nuclear Reactor Systems - Part II: Metallurgical Property Challenges

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ren, Weiju

2010-01-01

Alloy 617 is currently considered as a leading candidate material for high temperature components in the Gen IV Nuclear Reactor Systems. Because of the unprecedented severe working conditions beyond its commercial service experience required by the Gen IV systems, the alloy faces various challenges in both mechanical and metallurgical properties. Following a previous paper discussing the mechanical property challenges, this paper is focused on the challenges and issues in metallurgical properties of the alloy for the intended nuclear application. Considerations are given in details about its metallurgical stability and aging evolution, aging effects on mechanical properties, potential Co hazard, andmore » internal oxidation. Some research and development activities are suggested with discussions on viability to satisfy the Gen IV Nuclear Reactor System needs.« less

Mind, Brain and Education: A Decade of Evolution

ERIC Educational Resources Information Center

Schwartz, Marc

2015-01-01

This article examines the evolution of Mind, Brain, and Education (MBE), the field, alongside that of the International Mind, Brain and Education Society (IMBES). The reflections stem mostly from my observations while serving as vice president, president-elect, and president of IMBES during the past 10 years. The article highlights the evolution…

Thermodynamic stability of biomolecules and evolution.

PubMed

Chakravarty, Ashim K

2017-08-01

The thermodynamic stability of biomolecules in the perspective of evolution is a complex issue and needs discussion. Intra molecular bonds maintain the structure and the state of internal energy (E) of a biomolecule at "local minima". In this communication, possibility of loss in internal energy level of a biomolecule through the changes in the bonds has been discussed, that might earn more thermodynamic stability for the molecule. In the process variations in structure and functions of the molecule could occur. Thus, E of a biomolecule is likely to have energy stature for minimization. Such change in energy status is an intrinsic factor for evolving biomolecules buying more stability and generating variations in the structure and function of DNA molecules undergoing natural selection. Thus, the variations might very well contribute towards the process of evolution. A brief discussion on conserved sequence in the light of proposition in this communication has been made at the end. Extension of the idea may resolve certain standing problems in evolution, such as maintenance of conserved sequences in genome of diverse species, pre- versus post adaptive mutations, 'orthogenesis', etc. Copyright © 2017 Elsevier Ltd. All rights reserved.

Space Shuttle Main Engine (SSME) Evolution

NASA Technical Reports Server (NTRS)

Worlund, Len A.; Hastings, J. H.; McCool, Alex (Technical Monitor)

2001-01-01

The SSME when developed in the 1970's was a technological leap in space launch propulsion system design. The engine has safely supported the space shuttle for the last two decades and will be required for at least another decade to support human space flight to the international space station. This paper discusses the continued improvements and maturing of the system to its current state and future considerations for its critical role in the nations space program. Discussed are the initiatives of the late 1980's, which lead to three major upgrades through the 1990's. The current capabilities of the propulsion system are defined in the areas of highest programmatic importance: ascent risk, in-flight abort thrust, reusability, and operability. Future initiatives for improved shuttle safety, the paramount priority of the Space Shuttle program are discussed.

Self-organization and feedback effects in the shock compressed media

NASA Astrophysics Data System (ADS)

Khantuleva, Tatyana

2005-07-01

New theoretical approach to the transport in condensed matter far from equilibrium combines methods of statistical mechanics and cybernetic physics in order to construct closed mathematical model of a system with self-organization and self-regulation. Mesoscopic effects are considered as a result of the structure formation and the feedback effects in an open system under dynamic loading. Nonequilibrium state equations had been involved to incorporate the velocity dispersion. Integrodifferential balance equations describe both wave and dissipative transport properties. Boundary conditions determine the internal scale spectra. The model is completed by the feedback that introduces the structure evolution basing the methods of cybernetic physics. The obtained results open a wide prospective for the control methods in applications to new technologies, intellectual systems and prediction of catastrophic phenomena.

Ganymede: A Window into the Evolution of the Jupiter System (Invited)

NASA Astrophysics Data System (ADS)

Collins, G. C.

2009-12-01

Ganymede is unique in that it is the largest satellite in the solar system, the most centrally condensed solid body in the solar system, and the only solid body in the outer solar system known to posses an internally generated magnetic field. At the same time, its surface displays an array of geologic features spanning a wide range of ages and heat flow regimes, which serve as a reference point for understanding features on many other icy satellites. Ganymede’s geological history records evidence of the internal evolution of a large icy satellite, dynamical interactions with the other Galilean satellites, and the evolution of the population of small bodies impacting the surfaces of the satellites. Understanding Ganymede’s structure and history is an important key to understanding the Jupiter system, and large satellite systems around giant planets in general. Summarized here are some of the important questions we currently have about Ganymede: 1) Ganymede is highly differentiated, while its close sibling Callisto is not. What triggered differentiation? Did Ganymede differentiate near the time of accretion, or later in solar system history? 2) Modeling of Ganymede’s gravity field indicates there may be several near-surface mass anomalies. What causes gravity anomalies on icy satellites? What is the link with topography? 3) Two thirds of Ganymede’s surface is covered by bright grooved terrain, recording an episode of intense geological activity. Since the formation of grooved terrain, it appears that heat flow has decreased over time. Did Ganymede experience a pulse of tidal heating that triggered grooved terrain formation? Is it related to interior differentiation? Is it a record of Ganymede’s capture into the Laplace resonance with Europa and Io? 4) Ganymede’s internally generated magnetic field is enclosed within Jupiter’s strong magnetic field, creating a unique environment in our solar system for studying magnetic reconnection and other interaction processes. How is Ganymede’s field generated, and how long has it persisted? 5) Ganymede also appears to have an induced magnetic field, which is evidence for a subsurface ocean. Confirmation of the existence of this ocean and its size are important science goals at Ganymede. How has the ocean varied over time, and what is the composition and biological potential of the ocean? 6) The boundary between open and closed magnetic field lines intersecting Ganymede’s surface is clearly visible in color images, showing the effect of different space weathering conditions on the same starting material. How does the magnetic field shield the surface from radiolytic processes, and how can this help us understand processes on the surfaces of unshielded Galilean satellites? 7) Ganymede’s surface is mostly water ice, with evidence for Europa-like hydrated salts and Callisto-like tholins and silicate dust. How variable is the composition of the ice shell? How is the distribution of various non-ice materials related to the surface geology? The Europa Jupiter System Mission currently being planned by NASA and ESA includes a Jupiter Ganymede Orbiter element that would provide us with much of the necessary data to answer the outstanding science questions above. (Acknowledgements to my coauthors on the Decadal Survey Community White Paper on Ganymede science questions)

A Multiscale Nested Modeling Framework to Simulate the Interaction of Surface Gravity Waves with Nonlinear Internal Gravity Waves

DTIC Science & Technology

2015-09-30

We aim at understanding the impact of tidal , seasonal, and mesoscale variability of the internal wave field and how it influences the surface waves ...Interaction of Surface Gravity Waves with Nonlinear Internal Gravity Waves Lian Shen St. Anthony Falls Laboratory and Department of Mechanical...on studying surface gravity wave evolution and spectrum in the presence of surface currents caused by strongly nonlinear internal solitary waves

Demonstration of fully enabled data center subsystem with embedded optical interconnect

NASA Astrophysics Data System (ADS)

Pitwon, Richard; Worrall, Alex; Stevens, Paul; Miller, Allen; Wang, Kai; Schmidtke, Katharine

2014-03-01

The evolution of data storage communication protocols and corresponding in-system bandwidth densities is set to impose prohibitive cost and performance constraints on future data storage system designs, fuelling proposals for hybrid electronic and optical architectures in data centers. The migration of optical interconnect into the system enclosure itself can substantially mitigate the communications bottlenecks resulting from both the increase in data rate and internal interconnect link lengths. In order to assess the viability of embedding optical links within prevailing data storage architectures, we present the design and assembly of a fully operational data storage array platform, in which all internal high speed links have been implemented optically. This required the deployment of mid-board optical transceivers, an electro-optical midplane and proprietary pluggable optical connectors for storage devices. We present the design of a high density optical layout to accommodate the midplane interconnect requirements of a data storage enclosure with support for 24 Small Form Factor (SFF) solid state or rotating disk drives and the design of a proprietary optical connector and interface cards, enabling standard drives to be plugged into an electro-optical midplane. Crucially, we have also modified the platform to accommodate longer optical interconnect lengths up to 50 meters in order to investigate future datacenter architectures based on disaggregation of modular subsystems. The optically enabled data storage system has been fully validated for both 6 Gb/s and 12 Gb/s SAS data traffic conveyed along internal optical links.

The generation and propagation of internal gravity waves in a rotating fluid

NASA Technical Reports Server (NTRS)

Maxworthy, T.; Chabert Dhieres, G.; Didelle, H.

1984-01-01

The present investigation is concerned with an extension of a study conducted bu Maxworthy (1979) on internal wave generation by barotropic tidal flow over bottom topography. A short series of experiments was carried out during a limited time period on a large (14-m diameter) rotating table. It was attempted to obtain, in particular, information regarding the plan form of the waves, the exact character of the flow over the obstacle, and the evolution of the waves. The main basin was a dammed section of a long free surface water tunnel. The obstacle was towed back and forth by a wire harness connected to an electronically controlled hydraulic piston, the stroke and period of which could be independently varied. Attention is given to the evolution of the wave crests, the formation of solitary wave groups the evolution of the three-dimensional wave field wave shapes, the wave amplitudes, and particle motion.

Evolution of Near-Surface Internal and External Oxide Morphology During High-Temperature Selective Oxidation of Steels

NASA Astrophysics Data System (ADS)

Story, Mary E.; Webler, Bryan A.

2018-05-01

In this work we examine some observations made using high-temperature confocal scanning laser microscopy (HT-CSLM) during selective oxidation experiments. A plain carbon steel and advanced high-strength steel (AHSS) were selectively oxidized at high temperature (850-900°C) in either low oxygen or water vapor atmospheres. Surface evolution, including thermal grooving along grain boundaries and oxide growth, was viewed in situ during heating. Experiments investigated the influence of the microstructure and oxidizing atmosphere on selective oxidation behavior. Sequences of CSLM still frames collected during the experiment were processed with ImageJ to obtain histograms that showed a general darkening trend indicative of oxidation over time with all samples. Additional ex situ scanning electron microscopy and energy dispersive spectroscopy analysis supported in situ observations. Distinct oxidation behavior was observed for each case. Segregation, grain orientation, and extent of internal oxidation were all found to strongly influence surface evolution.

DFT investigation on two-dimensional GeS/WS2 van der Waals heterostructure for direct Z-scheme photocatalytic overall water splitting

NASA Astrophysics Data System (ADS)

Ju, Lin; Dai, Ying; Wei, Wei; Li, Mengmeng; Huang, Baibiao

2018-03-01

Recently, extensive attention has been paid to the direct Z-scheme systems for photocatalytic water splitting where carriers migrate directly between the two semiconductors without a redox mediator. In the present work, the electronic structure and related properties of two-dimensional (2D) van de Waals (vdW) GeS/WX2 (X = O, S, Se, Te) heterojunction are systematically investigated by first-principles calculations. Our results demonstrate that, the GeS/WS2 heterojunction could form a direct Z-scheme system for photocatalytic water splitting, whereas the GeS/WX2 (X = O, Se, Te) can't, because of their respective unsuitable electronic structures. For the GeS/WS2 heterojunction, the GeS and WS2 monolayers serve as photocatalysts for the hydrogen evolution reactionand oxygen evolution reaction, respectively. The internal electric field induced by the electron transfer at the interface can promote the separation of photo-generated charge carriers and formation of the interface Z-scheme electron transfer. Remarkably, the designed GeS/WS2 heterojunction not only enhances the hydrogen production activity of GeS and the oxygen production ability of WS2 but also improves the light absorption of the two monolayers by reducing the band gaps. Moreover, it is found that narrowing the interlayer distance could enhance the internal electric field, improving the photocatalytic ability of the vdW heterojunction. This work provides fundamental insights for further design and preparation of emergent metal dichalcogenide catalysts, beneficial for the development in clean energy.

The down canyon evolution of submarine sediment density flows

NASA Astrophysics Data System (ADS)

Parsons, D. R.; Barry, J.; Clare, M. A.; Cartigny, M.; Chaffey, M. R.; Gales, J. A.; Gwiazda, R.; Maier, K. L.; McGann, M.; Paull, C. K.; O'Reilly, T. C.; Rosenberger, K. J.; Simmons, S.; Sumner, E. J.; Talling, P.; Xu, J.

2017-12-01

Submarine density flows, known as turbidity currents, transfer globally significant volumes of terrestrial and shelf sediments, organic carbon, nutrients and fresher-water into the deep ocean. Understanding such flows has wide implications for global organic carbon cycling, the functioning of deep-sea ecosystems, seabed infrastructure hazard assessments, and interpreting geological archives of Earth history. Only river systems transport comparable volumes of sediment over such large areas of the globe. Despite their clear importance, there are remarkably few direct measurements of these oceanic turbidity currents in action. Here we present results from the multi-institution Coordinated Canyon Experiment (CCE) which deployed multiple moorings along the axis of Monterey Canyon (offshore California). An array of six moorings, with downward looking acoustic Doppler current profilers (ADCP) were positioned along the canyon axis from 290 m to 1850 m water depth. The ADCPs reveal the internal flow structure of submarine density flows at each site. We use a novel inversion method to reconstruct the suspended sediment concentration and flow stratification field during each event. Together the six moorings provide the first ever views of the internal structural evolution of turbidity current events as they evolve down system. Across the total 18-month period of deployment at least 15 submarine sediment density flows were measured with velocities up to 8.1 m/sec, with three of these flows extending 50 kms down the canyon beyond the 1850 m water depth mooring. We use these novel data to highlight the controls on ignition, interval structure and collapse of individual events and discuss the implications for the functioning and deposits produced by these enigmatic flows.

Continuing the International Roadmapping Effort - An Introduction to the Evolution of the ISECG Global Exploration Roadmap

NASA Astrophysics Data System (ADS)

Schlutz, Juergen; Hufenbach, Bernhard; Laurini, Kathy; Spiero, Francois

2016-07-01

Future space exploration goals call for sending humans and robots beyond low Earth orbit and establishing sustained access to destinations such as the Moon, asteroids and Mars. Space agencies participating in the International Space Exploration Coordination Group (ISECG) are discussing an international approach for achieving these goals, documented in ISECG's Global Exploration Roadmap (GER). The GER reference scenario reflects a step-wise evolution of critical capabilities from ISS to missions in the lunar vicinity in preparation for the journey of humans to Mars. As ISECG agencies advance their individual planning, they also advance the mission themes and reference architecture of the GER to consolidate common goals, near-term mission scenarios and initial opportunities for collaboration. In this context, particular focus has been given to the Better understanding and further refinement of cislunar infrastructure and potential lunar transportation architecture Interaction with international science communities to identify and articulate the scientific opportunities of the near-term exploration mission themes Coordination and consolidation of interest in lunar polar volatiles prospecting and potential for in-situ resource utilisation Identification and articulation of the benefits from exploration and the technology transfer activities The paper discusses the ongoing roadmapping activity of the ISECG agencies. It provides an insight into the status of the above activities and an outlook towards the evolution of the GER that is currently foreseen in the 2017 timeframe.

Contrasting magmatic structures between small plutons and batholiths emplaced at shallow crustal level (Sierras de Córdoba, Argentina)

NASA Astrophysics Data System (ADS)

Pinotti, Lucio P.; D'Eramo, Fernando J.; Weinberg, Roberto F.; Demartis, Manuel; Tubía, José María; Coniglio, Jorge E.; Radice, Stefania; Maffini, M. Natalia; Aragón, Eugenio

2016-11-01

Processes like injection, magma flow and differentiation and influence of the regional strain field are here described and contrasted to shed light on their role in the formation of small plutons and large batholiths their magmatic structures. The final geometric and compositional arrangement of magma bodies are a complex record of their construction and internal flow history. Magma injection, flow and differentiation, as well as regional stresses, all control the internal nature of magma bodies. Large magma bodies emplaced at shallow crustal levels result from the intrusion of multiple magma batches that interact in a variety of ways, depending on internal and external dynamics, and where the early magmatic, growth-related structures are commonly overprinted by subsequent history. In contrast, small plutons emplaced in the brittle-ductile transition more likely preserve growth-related structures, having a relatively simple cooling history and limited internal magma flow. Outcrop-scale magmatic structures in both cases record a rich set of complementary information that can help elucidate their evolution. Large and small granitic bodies of the Sierra Pampeanas preserve excellent exposures of magmatic structures that formed as magmas stepped through different rheological states during pluton growth and solidification. These structures reveal not only the flow pattern inside magma chambers, but also the rheological evolution of magmas in response to temperature evolution.

Constraining the volatile fraction of planets from transit observations

NASA Astrophysics Data System (ADS)

Alibert, Y.

2016-06-01

Context. The determination of the abundance of volatiles in extrasolar planets is very important as it can provide constraints on transport in protoplanetary disks and on the formation location of planets. However, constraining the internal structure of low-mass planets from transit measurements is known to be a degenerate problem. Aims: Using planetary structure and evolution models, we show how observations of transiting planets can be used to constrain their internal composition, in particular the amount of volatiles in the planetary interior, and consequently the amount of gas (defined in this paper to be only H and He) that the planet harbors. We first explore planets that are located close enough to their star to have lost their gas envelope. We then concentrate on planets at larger distances and show that the observation of transiting planets at different evolutionary ages can provide statistical information on their internal composition, in particular on their volatile fraction. Methods: We computed the evolution of low-mass planets (super-Earths to Neptune-like) for different fractions of volatiles and gas. We used a four-layer model (core, silicate mantle, icy mantle, and gas envelope) and computed the internal structure of planets for different luminosities. With this internal structure model, we computed the internal and gravitational energy of planets, which was then used to derive the time evolution of the planet. Since the total energy of a planet depends on its heat capacity and density distribution and therefore on its composition, planets with different ice fractions have different evolution tracks. Results: We show for low-mass gas-poor planets that are located close to their central star that assuming evaporation has efficiently removed the entire gas envelope, it is possible to constrain the volatile fraction of close-in transiting planets. We illustrate this method on the example of 55 Cnc e and show that under the assumption of the absence of gas, the measured mass and radius imply at least 20% of volatiles in the interior. For planets at larger distances, we show that the observation of transiting planets at different evolutionary ages can be used to set statistical constraints on the volatile content of planets. Conclusions: These results can be used in the context of future missions like PLATO to better understand the internal composition of planets, and based on this, their formation process and potential habitability.

Real-time spectral interferometry probes the internal dynamics of femtosecond soliton molecules

NASA Astrophysics Data System (ADS)

Herink, G.; Kurtz, F.; Jalali, B.; Solli, D. R.; Ropers, C.

2017-04-01

Solitons, particle-like excitations ubiquitous in many fields of physics, have been shown to exhibit bound states akin to molecules. The formation of such temporal soliton bound states and their internal dynamics have escaped direct experimental observation. By means of an emerging time-stretch technique, we resolve the evolution of femtosecond soliton molecules in the cavity of a few-cycle mode-locked laser. We track two- and three-soliton bound states over hundreds of thousands of consecutive cavity roundtrips, identifying fixed points and periodic and aperiodic molecular orbits. A class of trajectories acquires a path-dependent geometrical phase, implying that its dynamics may be topologically protected. These findings highlight the importance of real-time detection in resolving interactions in complex nonlinear systems, including the dynamics of soliton bound states, breathers, and rogue waves.

International institutions, global health initiatives and the challenge of sustainability: lessons from the Brazilian AIDS programme.

PubMed

Le Loup, G; Fleury, S; Camargo, K; Larouzé, B

2010-01-01

The sustainability of successful public health programmes remains a challenge in low and middle income settings. These programmes are often subjected to mobilization-demobilization cycle. Indeed, political and organizational factors are of major importance to ensure this sustainability. The cooperation between the World Bank and the Brazilian AIDS programme highlights the role of international institutions and global health initiatives (GHI), not only to scale up programmes but also to guarantee their stability and sustainability, at a time when advocacy is diminishing and vertical programmes are integrated within health systems. This role is critical at the local level, particularly when economic crisis may hamper the future of public health programmes. Political and organizational evolution should be monitored and warnings should trigger interventions of GHI before the decline of these programmes.

Observation and integrated Earth-system science: A roadmap for 2016-2025

NASA Astrophysics Data System (ADS)

Simmons, Adrian; Fellous, Jean-Louis; Ramaswamy, Venkatachalam; Trenberth, Kevin; Asrar, Ghassem; Balmaseda, Magdalena; Burrows, John P.; Ciais, Philippe; Drinkwater, Mark; Friedlingstein, Pierre; Gobron, Nadine; Guilyardi, Eric; Halpern, David; Heimann, Martin; Johannessen, Johnny; Levelt, Pieternel F.; Lopez-Baeza, Ernesto; Penner, Joyce; Scholes, Robert; Shepherd, Ted

2016-05-01

This report is the response to a request by the Committee on Space Research of the International Council for Science to prepare a roadmap on observation and integrated Earth-system science for the coming ten years. Its focus is on the combined use of observations and modelling to address the functioning, predictability and projected evolution of interacting components of the Earth system on timescales out to a century or so. It discusses how observations support integrated Earth-system science and its applications, and identifies planned enhancements to the contributing observing systems and other requirements for observations and their processing. All types of observation are considered, but emphasis is placed on those made from space. The origins and development of the integrated view of the Earth system are outlined, noting the interactions between the main components that lead to requirements for integrated science and modelling, and for the observations that guide and support them. What constitutes an Earth-system model is discussed. Summaries are given of key cycles within the Earth system. The nature of Earth observation and the arrangements for international coordination essential for effective operation of global observing systems are introduced. Instances are given of present types of observation, what is already on the roadmap for 2016-2025 and some of the issues to be faced. Observations that are organised on a systematic basis and observations that are made for process understanding and model development, or other research or demonstration purposes, are covered. Specific accounts are given for many of the variables of the Earth system. The current status and prospects for Earth-system modelling are summarized. The evolution towards applying Earth-system models for environmental monitoring and prediction as well as for climate simulation and projection is outlined. General aspects of the improvement of models, whether through refining the representations of processes that are already incorporated or through adding new processes or components, are discussed. Some important elements of Earth-system models are considered more fully. Data assimilation is discussed not only because it uses observations and models to generate datasets for monitoring the Earth system and for initiating and evaluating predictions, in particular through reanalysis, but also because of the feedback it provides on the quality of both the observations and the models employed. Inverse methods for surface-flux or model-parameter estimation are also covered. Reviews are given of the way observations and the processed datasets based on them are used for evaluating models, and of the combined use of observations and models for monitoring and interpreting the behaviour of the Earth system and for predicting and projecting its future. A set of concluding discussions covers general developmental needs, requirements for continuity of space-based observing systems, further long-term requirements for observations and other data, technological advances and data challenges, and the importance of enhanced international co-operation.

Observation and integrated Earth-system science: A roadmap for 2016–2025

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simmons, Adrian; Fellous, Jean-Louis; Ramaswamy, V.

This report is the response to a request by the Committee on Space Research of the International Council for Science to prepare a roadmap on observation and integrated Earth-system science for the coming ten years. Its focus is on the combined use of observations and modelling to address the functioning, predictability and projected evolution of interacting components of the Earth system on timescales out to a century or so. It discusses how observations support integrated Earth-system science and its applications, and identifies planned enhancements to the contributing observing systems and other requirements for observations and their processing. All types ofmore » observation are considered, but emphasis is placed on those made from space. The origins and development of the integrated view of the Earth system are outlined, noting the interactions between the main components that lead to requirements for integrated science and modelling, and for the observations that guide and support them. What constitutes an Earth-system model is discussed. Summaries are given of key cycles within the Earth system. The nature of Earth observation and the arrangements for international coordination essential for effective operation of global observing systems are introduced. Instances are given of present types of observation, what is already on the roadmap for 2016–2025 and some of the issues to be faced. Observations that are organized on a systematic basis and observations that are made for process understanding and model development, or other research or demonstration purposes, are covered. Specific accounts are given for many of the variables of the Earth system. The current status and prospects for Earth-system modelling are summarized. The evolution towards applying Earth-system models for environmental monitoring and prediction as well as for climate simulation and projection is outlined. General aspects of the improvement of models, whether through refining the representations of processes that are already incorporated or through adding new processes or components, are discussed. Some important elements of Earth-system models are considered more fully. Data assimilation is discussed not only because it uses observations and models to generate datasets for monitoring the Earth system and for initiating and evaluating predictions, in particular through reanalysis, but also because of the feedback it provides on the quality of both the observations and the models employed. Inverse methods for surface-flux or model-parameter estimation are also covered. Reviews are given of the way observations and the processed datasets based on them are used for evaluating models, and of the combined use of observations and models for monitoring and interpreting the behaviour of the Earth system and for predicting and projecting its future. A set of concluding discussions covers general developmental needs, requirements for continuity of space-based observing systems, further long-term requirements for observations and other data, technological advances and data challenges, and the importance of enhanced international co-operation.« less

Measuring the Internal Structure and Physical Conditions in Star and Planet Forming Clouds Core: Toward a Quantitative Description of Cloud Evolution

NASA Technical Reports Server (NTRS)

Lada, Charles J.

2005-01-01

This grant funds a research program to use infrared extinction measurements to probe the detailed structure of dark molecular cloud cores and investigate the physical conditions which give rise to star and planet formation. The goals of this program are to acquire, reduce and analyze deep infrared and molecular-line observations of a carefully selected sample of nearby dark clouds in order to internal structure of starless cloud cores and to quantitatively investigate the evolution of such structure through the star and planet formation process. During the second year of this grant, progress toward these goals is discussed.

Measuring the Internal Structure and Physical Conditions in Star and Planet Forming Clouds Cores: Towards a Quantitative Description of Cloud Evolution

NASA Technical Reports Server (NTRS)

Lada, Charles J.

2004-01-01

This grant funds a research program to use infrared extinction measurements to probe the detailed structure of dark molecular cloud cores and investigate the physical conditions which give rise to star and planet formation. The goals of this program are to acquire, reduce and analyze deep infrared and molecular-line observations of a carefully selected sample of nearby dark clouds in order to determine the detailed initial conditions for star formation from quantitative measurements of the internal structure of starless cloud cores and to quantitatively investigate the evolution of such structure through the star and planet formation process.

Assessing the role of internal climate variability in Antarctica's contribution to future sea-level rise

NASA Astrophysics Data System (ADS)

Tsai, C. Y.; Forest, C. E.; Pollard, D.

2017-12-01

The Antarctic ice sheet (AIS) has the potential to be a major contributor to future sea-level rise (SLR). Current projections of SLR due to AIS mass loss remain highly uncertain. Better understanding of how ice sheets respond to future climate forcing and variability is essential for assessing the long-term risk of SLR. However, the predictability of future climate is limited by uncertainties from emission scenarios, model structural differences, and the internal variability that is inherently generated within the fully coupled climate system. Among those uncertainties, the impact of internal variability on the AIS changes has not been explicitly assessed. In this study, we quantify the effect of internal variability on the AIS evolutions by using climate fields from two large-ensemble experiments using the Community Earth System Model to force a three-dimensional ice sheet model. We find that internal variability of climate fields, particularly atmospheric fields, among ensemble members leads to significantly different AIS responses. Our results show that the internal variability can cause about 80 mm differences of AIS contribution to SLR by 2100 compared to the ensemble-mean contribution of 380-450 mm. Moreover, using ensemble-mean climate fields as the forcing in the ice sheet model does not produce realistic simulations of the ice loss. Instead, it significantly delays the onset of retreat of the West Antarctic Ice Sheet for up to 20 years and significantly underestimates the AIS contribution to SLR by 0.07-0.11 m in 2100 and up to 0.34 m in the 2250's. Therefore, because the uncertainty caused by internal variability is irreducible, we seek to highlight a critical need to assess the role of internal variability in projecting the AIS loss over the next few centuries. By quantifying the impact of internal variability on AIS contribution to SLR, policy makers can obtain more robust estimates of SLR and implement suitable adaptation strategies.

[The effects of ethanol on the evolution of the acute benzodiazepine poisoning].

PubMed

Puha, Gabriela; Hurjui, J; Lupuşoru, Cătălina Elena; Sorodoc, L

2011-01-01

The depressing effects on the nervous central system (NCS) induced by benzodiazepines and ethanol are similar. The complications are rare in the benzodiazepine poisoning, but are a lot more frequent in association with other depressing drugs for the NCS (especially alcohol). We analyzed retrospectively patients with benzodiazepine poisoning admitted in the Internal Medicine Clinic - Toxicology during 2003 - 2009.The study attempted a complex evaluation of the consequences of acute and chronic alcoholism on the evolution of acute benzodiazepinepoisoning and the description of the clinic evolution and paraclinical particularities of the patients under investigation. 343 patients with benzodiazepine poisoning were admitted, 150 were tested through measurement of alcohol level, leading to values between 1 - 415 mg/dl. Chronic alcoholism in personal pathological antecedents of the patients determined a relative risk of intoxication 1.46 times higher. The hospitalization period varied from 1 to 8 days for patients with chronic alcoholism and from 1 to 14 days for patients with acute alcoholism, a statistically important difference. During the period under investigation, from the total of patients admitted for acute benzodiazepine poisoning, 2 deaths were registered. Of the two deaths, one patient showed ethanol coingestion.

Understanding the reaction of nuclear graphite with molecular oxygen: Kinetics, transport, and structural evolution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kane, Joshua J.; Contescu, Cristian I.; Smith, Rebecca E.

A thorough understanding of oxidation is important when considering the health and integrity of graphite components in graphite reactors. For the next generation of graphite reactors, HTGRs specifically, an unlikely air ingress has been deemed significant enough to have made its way into the licensing applications of many international licensing bodies. While a substantial body of literature exists on nuclear graphite oxidation in the presence of molecular oxygen and significant efforts have been made to characterize oxidation kinetics of various grades, the value of existing information is somewhat limited. Often, multiple competing processes, including reaction kinetics, mass transfer, and microstructuralmore » evolution, are lumped together into a single rate expression that limits the ability to translate this information to different conditions. This article reviews the reaction of graphite with molecular oxygen in terms of the reaction kinetics, gas transport, and microstructural evolution of graphite. It also presents the foundations of a model for the graphite-molecular oxygen reaction system that is kinetically independent of graphite grade, and is capable of describing both the bulk and local oxidation rates under a wide range of conditions applicable to air-ingress.« less

Understanding the reaction of nuclear graphite with molecular oxygen: Kinetics, transport, and structural evolution

DOE PAGES

Kane, Joshua J.; Contescu, Cristian I.; Smith, Rebecca E.; ...

2017-06-08

A thorough understanding of oxidation is important when considering the health and integrity of graphite components in graphite reactors. For the next generation of graphite reactors, HTGRs specifically, an unlikely air ingress has been deemed significant enough to have made its way into the licensing applications of many international licensing bodies. While a substantial body of literature exists on nuclear graphite oxidation in the presence of molecular oxygen and significant efforts have been made to characterize oxidation kinetics of various grades, the value of existing information is somewhat limited. Often, multiple competing processes, including reaction kinetics, mass transfer, and microstructuralmore » evolution, are lumped together into a single rate expression that limits the ability to translate this information to different conditions. This article reviews the reaction of graphite with molecular oxygen in terms of the reaction kinetics, gas transport, and microstructural evolution of graphite. It also presents the foundations of a model for the graphite-molecular oxygen reaction system that is kinetically independent of graphite grade, and is capable of describing both the bulk and local oxidation rates under a wide range of conditions applicable to air-ingress.« less

The generation of meaningful information in molecular systems.

PubMed

Wills, Peter R

2016-03-13

The physico-chemical processes occurring inside cells are under the computational control of genetic (DNA) and epigenetic (internal structural) programming. The origin and evolution of genetic information (nucleic acid sequences) is reasonably well understood, but scant attention has been paid to the origin and evolution of the molecular biological interpreters that give phenotypic meaning to the sequence information that is quite faithfully replicated during cellular reproduction. The near universality and age of the mapping from nucleotide triplets to amino acids embedded in the functionality of the protein synthetic machinery speaks to the early development of a system of coding which is still extant in every living organism. We take the origin of genetic coding as a paradigm of the emergence of computation in natural systems, focusing on the requirement that the molecular components of an interpreter be synthesized autocatalytically. Within this context, it is seen that interpreters of increasing complexity are generated by series of transitions through stepped dynamic instabilities (non-equilibrium phase transitions). The early phylogeny of the amino acyl-tRNA synthetase enzymes is discussed in such terms, leading to the conclusion that the observed optimality of the genetic code is a natural outcome of the processes of self-organization that produced it. © 2016 The Author(s).

GLIMPCE Seismic reflection evidence of deep-crustal and upper-mantle intrusions and magmatic underplating associated with the Midcontinent Rift system of North America

USGS Publications Warehouse

Behrendt, John C.; Hutchinson, D.R.; Lee, M.; Thornber, C.R.; Tréhu, A.; Cannon, W.; Green, A.

1990-01-01

Deep-crustal and Moho reflections, recorded on vertical incidence and wide angle ocean bottom Seismometer (OBS) data in the 1986 GLIMPCE (Great Lakes International Multidisciplinary Program on Crustal Evolution) experiment, provide evidence for magmatic underplating and intrusions within the lower crust and upper mantle contemporaneous with crustal extension in the Midcontinent Rift system at 1100 Ma. The rift fill consists of 20-30 km (7-10 s) of basalt flows, secondary syn-rift volcaniclastic and post-basalt sedimentary rock. Moho reflections recorded in Lake Superior over the Midcontinent Rift system have times from 14-18 s (about 46 km to as great as 58 km) in contrast to times of about 11-13 s (about 36-42 km crustal thickness) beneath the surrounding Great Lakes. The Seismically complex deep-crust to mantle transition zone (30-60 km) in north-central Lake Superior, which is 100 km wider than the rift half-graben, reflects the complicated products of tectonic and magmatic interaction of lower-crustal and mantle components during evolution or shutdown of the aborted Midcontinent Rift. In effect, mantle was changed into crust by lowering Seismic velocity (through intrusion of lower density magmatic rocks) and increasing Moho (about 8.1 km s-1 depth. 

A Cross-Cultural Comparison of Korean and American Science Teachers' Views of Evolution and the Nature of Science

ERIC Educational Resources Information Center

Kim, Sun Young; Nehm, Ross H.

2011-01-01

Despite a few international comparisons of the evolutionary beliefs of the general public, comparatively less research has focused on science teachers. Cross-cultural studies offer profitable opportunities for exploring the interactions among knowledge and belief variables in regard to evolution in different socio-cultural contexts. We…

A study of lunar models based on Apollo and other data

NASA Technical Reports Server (NTRS)

1973-01-01

The research concerned with the interpretation of lunar data developed during the Apollo Program is reported. The areas of research include: X-ray emission spectra and molecular orbitals of lunar materials, magnetic properties of lunar rock, lunar features, thermal history and evolution of the moon, and the internal constitution and evolution of the moon.

The "New Family" Model: The Evolution of Group Treatment for Adult Survivors of Childhood Sexual Abuse.

ERIC Educational Resources Information Center

Kriedler, Maryhelen C.; Fluharty, Leslie Barnes

1994-01-01

Discusses the evolution of a group therapy protocol for adult survivors of incest and the theoretical model on which it is based, the learned helplessness model of depression. Learned helplessness theory supports the assumption that victims internalize trauma. Group activities were aimed at changing negative self-beliefs and at providing…

Evolution of the deep-sea fleet that supports Canada's international trade

DOT National Transportation Integrated Search

2002-01-01

This study identifies the flag-related trends of fleets used in Canada's international sea-borne trade relative to the world fleet during the 15-year period from 1985 to 1999. The goal is to determine if there is any indication that fleets that serve...

Evolution of a radio communication relay system

NASA Astrophysics Data System (ADS)

Nguyen, Hoa G.; Pezeshkian, Narek; Hart, Abraham; Burmeister, Aaron; Holz, Kevin; Neff, Joseph; Roth, Leif

2013-05-01

Providing long-distance non-line-of-sight control for unmanned ground robots has long been recognized as a problem, considering the nature of the required high-bandwidth radio links. In the early 2000s, the DARPA Mobile Autonomous Robot Software (MARS) program funded the Space and Naval Warfare Systems Center (SSC) Pacific to demonstrate a capability for autonomous mobile communication relaying on a number of Pioneer laboratory robots. This effort also resulted in the development of ad hoc networking radios and software that were later leveraged in the development of a more practical and logistically simpler system, the Automatically Deployed Communication Relays (ADCR). Funded by the Joint Ground Robotics Enterprise and internally by SSC Pacific, several generations of ADCR systems introduced increasingly more capable hardware and software for automatic maintenance of communication links through deployment of static relay nodes from mobile robots. This capability was finally tapped in 2010 to fulfill an urgent need from theater. 243 kits of ruggedized, robot-deployable communication relays were produced and sent to Afghanistan to extend the range of EOD and tactical ground robots in 2012. This paper provides a summary of the evolution of the radio relay technology at SSC Pacific, and then focuses on the latest two stages, the Manually-Deployed Communication Relays and the latest effort to automate the deployment of these ruggedized and fielded relay nodes.

Formal Definitions of Unbounded Evolution and Innovation Reveal Universal Mechanisms for Open-Ended Evolution in Dynamical Systems.

PubMed

Adams, Alyssa; Zenil, Hector; Davies, Paul C W; Walker, Sara Imari

2017-04-20

Open-ended evolution (OEE) is relevant to a variety of biological, artificial and technological systems, but has been challenging to reproduce in silico. Most theoretical efforts focus on key aspects of open-ended evolution as it appears in biology. We recast the problem as a more general one in dynamical systems theory, providing simple criteria for open-ended evolution based on two hallmark features: unbounded evolution and innovation. We define unbounded evolution as patterns that are non-repeating within the expected Poincare recurrence time of an isolated system, and innovation as trajectories not observed in isolated systems. As a case study, we implement novel variants of cellular automata (CA) where the update rules are allowed to vary with time in three alternative ways. Each is capable of generating conditions for open-ended evolution, but vary in their ability to do so. We find that state-dependent dynamics, regarded as a hallmark of life, statistically out-performs other candidate mechanisms, and is the only mechanism to produce open-ended evolution in a scalable manner, essential to the notion of ongoing evolution. This analysis suggests a new framework for unifying mechanisms for generating OEE with features distinctive to life and its artifacts, with broad applicability to biological and artificial systems.

Tidal dissipation in rotating low-mass stars and implications for the orbital evolution of close-in planets. I. From the PMS to the RGB at solar metallicity

NASA Astrophysics Data System (ADS)

Gallet, F.; Bolmont, E.; Mathis, S.; Charbonnel, C.; Amard, L.

2017-08-01

Context. Star-planet interactions must be taken into account in stellar models to understand the dynamical evolution of close-in planets. The dependence of the tidal interactions on the structural and rotational evolution of the star is of particular importance and should be correctly treated. Aims: We quantify how tidal dissipation in the convective envelope of rotating low-mass stars evolves from the pre-main sequence up to the red-giant branch depending on the initial stellar mass. We investigate the consequences of this evolution on planetary orbital evolution. Methods: We couple the tidal dissipation formalism previously described to the stellar evolution code STAREVOL and apply this coupling to rotating stars with masses between 0.3 and 1.4 M⊙. As a first step, this formalism assumes a simplified bi-layer stellar structure with corresponding averaged densities for the radiative core and the convective envelope. We use a frequency-averaged treatment of the dissipation of tidal inertial waves in the convection zone (but neglect the dissipation of tidal gravity waves in the radiation zone). In addition, we generalize a recent work by following the orbital evolution of close-in planets using the new tidal dissipation predictions for advanced phases of stellar evolution. Results: On the pre-main sequence the evolution of tidal dissipation is controlled by the evolution of the internal structure of the contracting star. On the main sequence it is strongly driven by the variation of surface rotation that is impacted by magnetized stellar winds braking. The main effect of taking into account the rotational evolution of the stars is to lower the tidal dissipation strength by about four orders of magnitude on the main sequence, compared to a normalized dissipation rate that only takes into account structural changes. Conclusions: The evolution of the dissipation strongly depends on the evolution of the internal structure and rotation of the star. From the pre-main sequence up to the tip of the red-giant branch, it varies by several orders of magnitude, with strong consequences for the orbital evolution of close-in massive planets. These effects are the strongest during the pre-main sequence, implying that the planets are mainly sensitive to the star's early history.

IPDA PDS4 Project: Towards an International Planetary Data Standard

NASA Astrophysics Data System (ADS)

Martinez, Santa; Roatsch, Thomas; Capria, Maria Teresa; Heather, David; Yamamoto, Yukio; Hughes, Steven; Stein, Thomas; Cecconi, Baptiste; Prashar, Ajay; Batanov, Oleg; Gopala Krishna, Barla

2016-07-01

The International Planetary Data Alliance (IPDA) is an international collaboration of space agencies with the main objective of facilitating discovery, access and use of planetary data managed across international boundaries. For this purpose, the IPDA has adopted the NASA's Planetary Data System (PDS) standard as the de-facto archiving standard, and is working towards the internationalisation of the new generation of the standards, called PDS4. PDS4 is the largest upgrade in the history of the PDS, and is a significant step towards an online, distributed, model-driven and service-oriented architecture international archive. Following the successful deployment of PDS4 to support NASA's LADEE and MAVEN missions, PDS4 was endorsed by IPDA in 2014. This has led to the adoption of PDS4 by a number of international space agencies (ESA, JAXA, ISRO and Roscosmos, among others) for their upcoming missions. In order to closely follow the development of the PDS4 standards and to coordinate the international contribution and participation in its evolution, a group of experts from each international agency is dedicated to review different aspects of the standards and to capture recommendations and requirements to ensure the international needs are met. The activities performed by this group cover the assessment and implementation of all aspects of PDS4, including its use, documentation, tools, validation strategies and information model. This contribution will present the activities carried out by this group and how this partnership between PDS and IPDA provides an excellent foundation towards an international platform for planetary science research.

Environmental, political, and economic determinants of water quality monitoring in Europe

NASA Astrophysics Data System (ADS)

Beck, Lucas; Bernauer, Thomas; Kalbhenn, Anna

2010-11-01

Effective monitoring is essential for effective pollution control in national and international water systems. To what extent are countries' monitoring choices driven by environmental criteria, as they should be? And to what extent are they also influenced by other factors, such as political and economic conditions? To address these questions, we describe and explain the evolution of one of the most important international environmental monitoring networks in Europe, the one for water quality, in the time period 1965-2004. We develop a geographic information system that contains information on the location of several thousand active monitoring stations in Europe. Using multivariate statistics, we then examine whether and to what extent the spatial and temporal clustering of monitoring intensity is driven by environmental, political, and economic factors. The results show that monitoring intensity is higher in river basins exposed to greater environmental pressure. However, political and economic factors also play a strong role in monitoring decisions: democracy, income, and peer pressure are conducive to monitoring intensity, and monitoring intensity generally increases over time. Moreover, even though monitoring is more intense in international upstream-downstream settings, we observe only a weak bias toward more monitoring downstream of international borders. In contrast, negative effects of European Union (EU) membership and runup to the EU's Water Framework Directive are potential reasons for concern. Our results strongly suggest that international coordination and standardization of water quality monitoring should be intensified. It will be interesting to apply our analytical approach also to other national and international monitoring networks, for instance, the U.S. National Water-Quality Assessment Program or the European Monitoring and Evaluation Program for air pollution.

Functional pleiotropy and mating system evolution in plants: frequency-independent mating.

PubMed

Jordan, Crispin Y; Otto, Sarah P

2012-04-01

Mutations that alter the morphology of floral displays (e.g., flower size) or plant development can change multiple functions simultaneously, such as pollen export and selfing rate. Given the effect of these various traits on fitness, pleiotropy may alter the evolution of both mating systems and floral displays, two characters with high diversity among angiosperms. The influence of viability selection on mating system evolution has not been studied theoretically. We model plant mating system evolution when a single locus simultaneously affects the selfing rate, pollen export, and viability. We assume frequency-independent mating, so our model characterizes prior selfing. Pleiotropy between increased viability and selfing rate reduces opportunities for the evolution of pure outcrossing, can favor complete selfing despite high inbreeding depression, and notably, can cause the evolution of mixed mating despite very high inbreeding depression. These results highlight the importance of pleiotropy for mating system evolution and suggest that selection by nonpollinating agents may help explain mixed mating, particularly in species with very high inbreeding depression. © 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.

Evolution of protoplanetary disks with dynamo magnetic fields

NASA Technical Reports Server (NTRS)

Reyes-Ruiz, M.; Stepinski, Tomasz F.

1994-01-01

The notion that planetary systems are formed within dusty disks is certainly not a new one; the modern planet formation paradigm is based on suggestions made by Laplace more than 200 years ago. More recently, the foundations of accretion disk theory where initially developed with this problem in mind, and in the last decade astronomical observations have indicated that many young stars have disks around them. Such observations support the generally accepted model of a viscous Keplerian accretion disk for the early stages of planetary system formation. However, one of the major uncertainties remaining in understanding the dynamical evolution of protoplanetary disks is the mechanism responsible for the transport of angular momentum and subsequent mass accretion through the disk. This is a fundamental piece of the planetary system genesis problem since such mechanisms will determine the environment in which planets are formed. Among the mechanisms suggested for this effect is the Maxwell stress associated with a magnetic field treading the disk. Due to the low internal temperatures through most of the disk, even the question of the existence of a magnetic field must be seriously studied before including magnetic effects in the disk dynamics. On the other hand, from meteoritic evidence it is believed that magnetic fields of significant magnitude existed in the earliest, PP-disk-like, stage of our own solar system's evolution. Hence, the hypothesis that PP disks are magnetized is not made solely on the basis of theory. Previous studies have addressed the problem of the existence of a magnetic field in a steady-state disk and have found that the low conductivity results in a fast diffusion of the magnetic field on timescales much shorter than the evolutionary timescale. Hence the only way for a magnetic field to exist in PP disks for a considerable portion of their lifetimes is for it to be continuously regenerated. In the present work, we present results on the self-consistent evolution of a turbulent PP disk including the effects of a dynamo-generated magnetic field.

Evolution of the Earth Observing System (EOS) Data and Information System (EOSDIS)

NASA Technical Reports Server (NTRS)

Ramapriyan, Hampapuram K.; Behnke, Jeanne; Sofinowski, Edwin; Lowe, Dawn; Esfandiari, Mary Ann

2008-01-01

One of the strategic goals of the U.S. National Aeronautics and Space Administration (NASA) is to "Develop a balanced overall program of science, exploration, and aeronautics consistent with the redirection of the human spaceflight program to focus on exploration". An important sub-goal of this goal is to "Study Earth from space to advance scientific understanding and meet societal needs." NASA meets this subgoal in partnership with other U.S. agencies and international organizations through its Earth science program. A major component of NASA s Earth science program is the Earth Observing System (EOS). The EOS program was started in 1990 with the primary purpose of modeling global climate change. This program consists of a set of space-borne instruments, science teams, and a data system. The instruments are designed to obtain highly accurate, frequent and global measurements of geophysical properties of land, oceans and atmosphere. The science teams are responsible for designing the instruments as well as scientific algorithms to derive information from the instrument measurements. The data system, called the EOS Data and Information System (EOSDIS), produces data products using those algorithms as well as archives and distributes such products. The first of the EOS instruments were launched in November 1997 on the Japanese satellite called the Tropical Rainfall Measuring Mission (TRMM) and the last, on the U.S. satellite Aura, were launched in July 2004. The instrument science teams have been active since the inception of the program in 1990 and have participation from Brazil, Canada, France, Japan, Netherlands, United Kingdom and U.S. The development of EOSDIS was initiated in 1990, and this data system has been serving the user community since 1994. The purpose of this chapter is to discuss the history and evolution of EOSDIS since its beginnings to the present and indicate how it continues to evolve into the future. this chapter is organized as follows. Sect. 7.2 provides a discussion of EOSDIS, its elements and their functions. Sect. 7.3 provides details regarding the move towards more distributed systems for supporting both the core and community needs to be served by NASA Earth science data systems. Sect. 7.4 discusses the use of standards and interfaces and their importance in EOSDIS. Sect. 7.5 provides details about the EOSDIS Evolution Study. Sect. 7.6 presents the implementation of the EOSDIS Evolution plan. Sect. 7.7 briefly outlines the progress that the implementation has made towards the 2015 Vision, followed by a summary in Sect. 7.8.

The middle atmosphere and space observations; International Summer School on Space Physics, Marseille, France, Aug. 1990, Proceedings

NASA Technical Reports Server (NTRS)

1991-01-01

Papers are presented on topics in the dynamics of the middle atmosphere, the homogeneous chemistry of gas-phase neutral constituents in the middle atmosphere, stratospheric turbulence, the stratospheric ozone balance considered as a coupled chemical system, and gases of biological origin in the atmosphere. Consideration is also given to lidar measurements of ozone, microwave techniques for the measurement of stratospheric constituents, the seasonal evolution of the extratropical middle atmosphere, the WINDII experiment on the UARS satellite, and the use of the European polar platform for middle-atmosphere research.

[Problems of exobiology: the origin of life on Earth].

PubMed

Tairbekov, M G; Klimovitskiĭ, V Ia; Il'in, E A

2003-01-01

The basic problem of exobiology is origin and evolution of life as a space phenomenon. Consideration is given to the facts for the space origin, spreading in the interstellar space of and invasion of the surface of planets by organic compounds, constituents of archetypes of living systems. The authors bring up to discussion the issues of life development under the conditions of Earth, and formation of the main properties of the living organisms differing in the level of organization. Outlined are some international projects on exobiological research in experiments with bio-objects on space platforms.

The Landsat program: Its origins, evolution, and impacts

USGS Publications Warehouse

Lauer, D.T.; Morain, S.A.; Salomonson, V.V.

1997-01-01

Landsat 1 began an era of space-based resource data collection that changed the way science, industry, governments, and the general public view the Earth. For the last 25 years, the Landsat program - despite being hampered by institutional problems and budget uncertainties - has successfully provided a continuous supply of synoptic, repetitive, multi-spectral data of the Earth's land areas. These data have profoundly affected programs for mapping resources, monitoring environmental changes, and assessing global habitability. The societal applications this program generated are so compelling that international systems have proliferated to carry on the tasks initiated with Landsat data.

Mars

NASA Technical Reports Server (NTRS)

Kieffer, Hugh H. (Editor); Jakosky, Bruce M. (Editor); Snyder, Conway W. (Editor); Matthews, Mildred S. (Editor)

1992-01-01

The present volume on Mars discusses visual, photographic and polarimetric telescopic observations, spacecraft exploration of Mars, the origin and thermal evolution of Mars, and the bulk composition, mineralogy, and internal structure of the planet. Attention is given to Martian gravity and topography, stress and tectonics on Mars, long-term orbital and spin dynamics of Mars, and Martian geodesy and cartography. Topics addressed include the physical volcanology of Mars, the canyon system on planet, Martian channels and valley networks, and ice in the Martian regolith. Also discussed are Martian aeolian processes, sediments, and features, polar deposits of Mars, dynamics of the Martian atmosphere, and the seasonal behavior of water on Mars.

[The thirty years of Acta Genetica Sinica].

PubMed

Li, Shao-Wu; Zhou, Su; Xue, Yong-Biao; Zhu, Li-Huang

2003-04-01

Acta Genetica Sinica (AGS) is sponsored by the Genetics Society of China and the Institute of Genetics and Developmental Biology of Chinese Academy of Sciences, and is published by Science Press. The journal is a leading national academic periodical and one of the Chinese key periodicals of natural sciences. Currently, AGS is being indexed by several well-known domestic and international indexing systems, such as the American Chemical Digest (CA), BIOSIS database, Biological Digest (BA), Medical Index and Russian Digest (P [symbol: see text]). Papers in the areas of genetics, developmental biology, cell molecular biology and evolution are regularly published by AGS.

Current status and recent research achievements in SiC/SiC composites

NASA Astrophysics Data System (ADS)

Katoh, Y.; Snead, L. L.; Henager, C. H.; Nozawa, T.; Hinoki, T.; Iveković, A.; Novak, S.; Gonzalez de Vicente, S. M.

2014-12-01

The silicon carbide fiber-reinforced silicon carbide matrix (SiC/SiC) composite system for fusion applications has seen a continual evolution from development a fundamental understanding of the material system and its behavior in a hostile irradiation environment to the current effort which is directed at a broad-based program of technology maturation program. In essence, over the past few decades this material system has steadily moved from a laboratory curiosity to an engineering material, both for fusion structural applications and other high performance application such as aerospace. This paper outlines the recent international scientific and technological achievements towards the development of SiC/SiC composite material technologies for fusion application and discusses future research directions. It also reviews the materials system in the larger context of progress to maturity as an engineering material for both the larger nuclear community and broader engineering applications.

Physical properties and catalog of EW-type eclipsing binaries observed by LAMOST

NASA Astrophysics Data System (ADS)

Qian, Sheng-Bang; He, Jia-Jia; Zhang, Jia; Zhu, Li-Ying; Shi, Xiang-Dong; Zhao, Er-Gang; Zhou, Xiao

2017-08-01

EW-type eclipsing binaries (hereafter called EWs) are strong interacting systems in which both component stars usually fill their critical Roche lobes and share a common envelope. Numerous EWs were discovered by several deep photometric surveys and there were about 40 785 EW-type binary systems listed in the international variable star index (VSX) by 2017 March 13. 7938 of them were observed with LAMOST by 2016 November 30 and their spectral types were identified. Stellar atmospheric parameters of 5363 EW-type binary stars were determined based on good spectroscopic observations. In the paper, those EWs are cataloged and their properties are analyzed. The distributions of orbital period (P), effective temperature (T), gravitational acceleration (log(g)), metallicity ([Fe/H]) and radial velocity (RV) are presented for these observed EW-type systems. It is shown that about 80.6% of sample stars have metallicity below zero, indicating that EW-type systems are old stellar populations. This is in agreement with the conclusion that EW binaries are formed from moderately close binaries through angular momentum loss via magnetic braking that takes a few hundred million to a few billion years. The unusually high metallicities of a few percent of EWs may be caused by contamination of material from the evolution of unseen neutron stars or black holes in the systems. The correlations between orbital period and effective temperature, gravitational acceleration and metallicity are presented and their scatters are mainly caused by (i) the presence of third bodies and (ii) sometimes wrongly determined periods. It is shown that some EWs contain evolved component stars and the physical properties of EWs mainly depend on their orbital periods. It is found that extremely short-period EWs may be older than their long-period cousins because they have lower metallicities. This reveals that they have a longer timescale of pre-contact evolution and their formation and evolution aremainly driven by angular momentum loss via magnetic braking.

Duality quantum algorithm efficiently simulates open quantum systems

PubMed Central

Wei, Shi-Jie; Ruan, Dong; Long, Gui-Lu

2016-01-01

Because of inevitable coupling with the environment, nearly all practical quantum systems are open system, where the evolution is not necessarily unitary. In this paper, we propose a duality quantum algorithm for simulating Hamiltonian evolution of an open quantum system. In contrast to unitary evolution in a usual quantum computer, the evolution operator in a duality quantum computer is a linear combination of unitary operators. In this duality quantum algorithm, the time evolution of the open quantum system is realized by using Kraus operators which is naturally implemented in duality quantum computer. This duality quantum algorithm has two distinct advantages compared to existing quantum simulation algorithms with unitary evolution operations. Firstly, the query complexity of the algorithm is O(d3) in contrast to O(d4) in existing unitary simulation algorithm, where d is the dimension of the open quantum system. Secondly, By using a truncated Taylor series of the evolution operators, this duality quantum algorithm provides an exponential improvement in precision compared with previous unitary simulation algorithm. PMID:27464855

Mainstreaming Caenorhabditis elegans in experimental evolution.

PubMed

Gray, Jeremy C; Cutter, Asher D

2014-03-07

Experimental evolution provides a powerful manipulative tool for probing evolutionary process and mechanism. As this approach to hypothesis testing has taken purchase in biology, so too has the number of experimental systems that use it, each with its own unique strengths and weaknesses. The depth of biological knowledge about Caenorhabditis nematodes, combined with their laboratory tractability, positions them well for exploiting experimental evolution in animal systems to understand deep questions in evolution and ecology, as well as in molecular genetics and systems biology. To date, Caenorhabditis elegans and related species have proved themselves in experimental evolution studies of the process of mutation, host-pathogen coevolution, mating system evolution and life-history theory. Yet these organisms are not broadly recognized for their utility for evolution experiments and remain underexploited. Here, we outline this experimental evolution work undertaken so far in Caenorhabditis, detail simple methodological tricks that can be exploited and identify research areas that are ripe for future discovery.

Dynamic self-organization of side-propelling colloidal rods: experiments and simulations.

PubMed

Vutukuri, Hanumantha Rao; Preisler, Zdeněk; Besseling, Thijs H; van Blaaderen, Alfons; Dijkstra, Marjolein; Huck, Wilhelm T S

2016-12-06

In recent years, there is a growing interest in designing artificial analogues of living systems, fueled not only by potential applications as 'smart micro-machines', but also by the demand for simple models that can be used to study the behavior of their more complex natural counterparts. Here, we present a facile, internally driven, experimental system comprised of fluorescently labeled colloidal silica rods of which the self-propulsion is powered by the decomposition of H 2 O 2 catalyzed by a length-wise half Pt coating of the particles in order to study how shape anisotropy and swimming direction affect the collective behavior. We investigated the emerging structures and their time evolution for various particle concentrations in (quasi-)two dimensional systems for three aspect ratios of the rods on a single particle level using a combination of experiments and simulations. We found that the dynamic self-organization relied on a competition between self-propulsion and phoretic attractions induced by phoresis of the rods. We observed that the particle clustering behavior depends on the concentration as well as the aspect ratio of the rods. Our findings provide a more detailed understanding of dynamic self-organization of anisotropic particles and the role the propulsion direction plays in internally driven systems.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cai, S.; Schaffer, J. E.; Yu, C.

In situ synchrotron X-ray diffraction testing was carried out on a martensitic and an austenitic NiTi wire to study the evolution of internal stresses and the stress-induced martensite (SIM) phase transformation during room temperature tensile deformation. From the point of lattice strain evolution, it is concluded that (1) for the martensitic NiTi wire, detwinning of the [011](B19') type II twins and the {010}(B19') compound twins is responsible for internal strains formed at the early stage of deformation. (2) The measured diffraction moduli of individual martensite families show large elastic anisotropy and strong influences of texture. (3) For the austenitic NiTimore » wire, internal residual stresses were produced due to transformation-induced plasticity, which is more likely to occur in austenite families that have higher elastic moduli than their associated martensite families. (4) Plastic deformation was observed in the SIM at higher stresses, which largely decreased the lower plateau stresses.« less

National military strategy in the post cold war era: Nuclear deterrence or an alternative. Study project

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pooley, G.R.

In the aftermath of the Cold War it becomes necessary to explore the validity of nuclear deterrence as the cornerstone of the United States National Military Strategy for the upcoming period of transition in international relations. Using the current world situation as a starting point, the evolving trends in international relations, arms control and nuclear proliferation, the strategic threat and the evolution of technology will be analyzed in an effort to forecast the complexion of international relations twenty years hence. Then, within this context, nuclear deterrence and a non nuclear alternative nonoffensive defense, proposed by the Danish political scientist, Bjornmore » Moller, will be examined. In the final analysis, this project will suggest an appropriate direction for the evolution of the United States' National Military Strategy which, in the opinion of the author, provides the best probability for long term world peace.« less

Effect of Tooling Material on the Internal Surface Quality of Ti6Al4V Parts Fabricated by Hot Isostatic Pressing

NASA Astrophysics Data System (ADS)

Cai, Chao; Song, Bo; Wei, Qingsong; Yan, Wu; Xue, Pengju; Shi, Yusheng

2017-01-01

For the net-shape hot isostatic pressing (HIP) process, control of the internal surface roughness of as-HIPped parts remains a challenge for practical engineering. To reveal the evolution mechanism of the internal surface of the parts during the HIP process, the effect of different tooling materials (H13, T8, Cr12 steel, and graphite) as internal cores on the interfacial diffusion and surface roughness was systematically studied.

Support for the existence of invertible maps between electronic densities and non-analytic 1-body external potentials in non-relativistic time-dependent quantum mechanics

NASA Astrophysics Data System (ADS)

Mosquera, Martín A.

2017-10-01

Provided the initial state, the Runge-Gross theorem establishes that the time-dependent (TD) external potential of a system of non-relativistic electrons determines uniquely their TD electronic density, and vice versa (up to a constant in the potential). This theorem requires the TD external potential and density to be Taylor-expandable around the initial time of the propagation. This paper presents an extension without this restriction. Given the initial state of the system and evolution of the density due to some TD scalar potential, we show that a perturbative (not necessarily weak) TD potential that induces a non-zero divergence of the external force-density, inside a small spatial subset and immediately after the initial propagation time, will cause a change in the density within that subset, implying that the TD potential uniquely determines the TD density. In this proof, we assume unitary evolution of wavefunctions and first-order differentiability (which does not imply analyticity) in time of the internal and external force-densities, electronic density, current density, and their spatial derivatives over the small spatial subset and short time interval.

Reservoir computer predictions for the Three Meter magnetic field time evolution

NASA Astrophysics Data System (ADS)

Perevalov, A.; Rojas, R.; Lathrop, D. P.; Shani, I.; Hunt, B. R.

2017-12-01

The source of the Earth's magnetic field is the turbulent flow of liquid metal in the outer core. Our experiment's goal is to create Earth-like dynamo, to explore the mechanisms and to understand the dynamics of the magnetic and velocity fields. Since it is a complicated system, predictions of the magnetic field is a challenging problem. We present results of mimicking the three Meter experiment by a reservoir computer deep learning algorithm. The experiment is a three-meter diameter outer sphere and a one-meter diameter inner sphere with the gap filled with liquid sodium. The spheres can rotate up to 4 and 14 Hz respectively, giving a Reynolds number near to 108. Two external electromagnets apply magnetic fields, while an array of 31 external and 2 internal Hall sensors measure the resulting induced fields. We use this magnetic probe data to train a reservoir computer to predict the 3M time evolution and mimic waves in the experiment. Surprisingly accurate predictions can be made for several magnetic dipole time scales. This shows that such a complicated MHD system's behavior can be predicted. We gratefully acknowledge support from NSF EAR-1417148.

Imaging and Modeling Nearby Stellar Systems through Infrared Interferometers

NASA Astrophysics Data System (ADS)

Che, Xiao; Monnier, J. D.; Ten Brummelaar, T.; Sturmann, L.; Millan-Gabet, R.; Baron, F.; Kraus, S.; Zhao, M.; CHARA

2014-01-01

Long-baseline infrared interferometers with sub-milliarcsecond angular resolution can now resolve photospheric features and the circumstellar environments of nearby massive stars. Closure phase measurements have made model-independent imaging possible. During the thesis, I have expanded Michigan Infrared Combiner (MIRC) from a 4-beam combiner to a 6-beam combiner to improve the (u,v) coverage, and installed Photometric Channels system to reduce the RMS of data by a factor of 3. I am also in charge of the Wavefront Sensor of the CHARA Adaptive Optics project to increase the sensitivity of the telescope array to enlarge the observable Young Stellar Objects (YSOs). My scientific research has focused on using mainly MIRC at CHARA to model and image rapidly rotating stars. The results are crucial for testing the next generation of stellar models that incorporate evolution of internal angular momentum. Observations of Be stars with MIRC have resolved the innermost parts of the disks, allowing us to study the evolution of the disks and star-disk interactions. I have also adopted a semi-analytical disk model to constrain Mid-InfraRed (MIR) disks of YSOs using interferometric and spectroscopic data.

Exobiology opportunities from Discovery-class missions. [Abstract only

NASA Technical Reports Server (NTRS)

Meyer, Michael A.; Rummel, John D.

1994-01-01

Discovery-class missions that are now planned, and those in the concept stage, have the potential to expand our knowledge of the origins and evolution of biogenic compounds, and ultimately, of the origins of life in the solar system. This class of missions, recently developed within NASA's Solar System Exploration Program, is designed to meet important scientific objectives within stringent guidelines--$150 million cap on development cost and a 3-year cap on the development schedule. The Discovery Program will effectively enable "faster, cheaper" missions to explore the inner solar system. The first two missions are Mars Environmental Survey (MESUR) Pathfinder and Near Earth Asteroid Rendezvous (NEAR). MESUR Pathfinder will be the first Discovery mission, with launch planned for November/December 1996. It will be primarily a technical demonstration and validation of the MESUR Program--a network of automated landers to study the internal structure, meteorology, and surface properties of Mars. Besides providing engineering data, Pathfinder will carry atmospheric instrumentation and imaging capabilities, and may deploy a microrover equipped with an alpha proton X-ray spectrometer to determine elemental composition, particularly the lighter elements of exobiological interest. NEAR is expected to be launched in 1998 and to rendezvous with a near-Earth asteroid for up to 1 year. During this time, the spacecraft will assess the asteroid's mass, size, density, map its surface topography and composition, determine its internal properties, and study its interaction with the interplanetary environment. A gamma ray or X-ray spectrometer will be used to determine elemental composition. An imaging spectrograph, with 0.35 to 2.5 micron spectral range, will be used to determine the asteroid's compositional disbribution. Of the 11 Discovery mission concepts that have been designated as warranting further study, several are promising in terms of determining the composition and chemical evolution of organic matter on small planetary bodies. The following mission concepts are of particular interest to the Exobiology Program: Cometary coma chemical composition, comet nucleus tour, near earth asteroid returned sample, small missions to asteroids and comets, and solar wind sample return. The following three Discovery mission concepts that have been targeted for further consideration are relevant to the study of the evolution of biogenic compounds: Comet nucleus penetrator, mainbelt asteroid rendezvous explorer, and the Mars polar Pathfinder.

A method for resilience assessment in dry Mediterranean socio-ecological systems

NASA Astrophysics Data System (ADS)

jucker riva, matteo; schwilch, gudrun; liniger, hanspeter

2016-04-01

Resilience is acknowledged as an important concept to understand and forecast the evolution of ecosystems. Even more so when these ecosystems are at risk of undergoing a regime shift that could radically modify its functioning and the provision of important ecosystem services. However, there is a lack of methodologies for practical assessment of resilience on the ground that could be useful to improve land management strategies. We present here a methodology based on the WOCAT approach to land management evaluation, that allows assessing in a semi quantitative way the resilience of a land use system, and in particular the role of land management in preventing, mitigating or fostering recovery following a disturbance. The first step of the evaluation centers on assessing the values of land users with regards to the provision of ESS and the perception of degradation; this allows defining the healthy state of the system in a participative way. Furthermore, scientific and experience knowledge are combined to assess the possible evolution of the system and of the internal and external pressure sources that can degrade it, and the impact of shocks and disturbances on the system. The contribution of land management practices to the resilience of the system is analyzed in detail, together with the resilience of land management itself across time, space and different disturbances. Results from the first application of the Resilience Assessment Tool in the study sites of the CASCADE project will be shown, along with some general conclusions about the most relevant factors playing a role in the resilience of dry Mediterranean socio-ecological systems.

Institute of Navigation, Annual Meeting, 47th, Williamsburg, VA, June 10-12, 1991, Proceedings

NASA Astrophysics Data System (ADS)

1991-11-01

The present volume of navigation and exploration discusses space exploration, mapping and geodesy, aircraft navigation, undersea navigation, land and vehicular location, international and legal aspects of navigation, the history of navigation technology and applications, Loran development and implementation, GPS and GLONASS developments, and search and rescue. Topics addressed include stabilization of low orbiting spacecraft using GPS, the employment of laser navigation for automatic rendezvous and docking systems, enhanced pseudostatic processing, and the expanding role of sensor fusion. Attention is given to a gravity-aided inertial navigation system, recent developments in aviation products liability and navigation, the ICAO future air navigation system, and Loran's implementation in NAS. Also discussed are Inmarsat integrated navigation/communication activities, the GPS program status, the evolution of military GPS technology into the Navcore V receiver engine, and Sarsat location algorithms.

Current Status and Recent Research Achievements in SiC/SiC Composites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Katoh, Yutai; Snead, Lance L.; Henager, Charles H.

2014-12-01

The development and maturation of the silicon carbide fiber-reinforced silicon carbide matrix (SiC/SiC) composite system for fusion applications has seen the evolution from fundamental development and understanding of the material system and its behavior in a hostile irradiation environment to the current effort which essentially is a broad-based program of technology, directed at moving this material class from a laboratory curiosity to an engineering material. This paper lays out the recent international scientific and technological achievements in the development of SiC/SiC composite material technologies for fusion application and will discuss future research directions. It also reviews the materials system inmore » the larger context of progress to maturity as an engineering material for both the larger nuclear community and for general engineering applications.« less

Decline in the Quality of Family Relationships Predicts Escalation in Children’s Internalizing Symptoms from Middle to Late Childhood

PubMed Central

Kochanska, Grazyna

2015-01-01

An integration of family systems perspectives with developmental psychopathology provides a framework for examining the complex interplay between family processes and developmental trajectories of child psychopathology over time. In a community sample of 98 families, we investigated the evolution of family relationships, across multiple subsystems of the family (i.e., interparental, mother-child, father-child), and the impact of these changing family dynamics on developmental trajectories of child internalizing symptoms over 6 years, from preschool age to pre-adolescence. Parent–child relationship quality was observed during lengthy sessions, consisting of multiple naturalistic, carefully scripted contexts. Each parent completed reports about interparental relationship satisfaction and child internalizing symptoms. To the extent that mothers experienced a steeper decline in interparental relationship satisfaction over time, children developed internalizing symptoms at a faster rate. Further, symptoms escalated at a faster rate to the extent that negative mother-child relationship quality increased (more negative affect expressed by both mother and child, greater maternal power assertion) and positive mother-child relationship quality decreased (less positive affect expressed by both mother and child, less warmth and positive reciprocity). Time-lagged growth curve analyses established temporal precedence such that decline in family relationships preceded escalation in child internalizing symptoms. Results suggest that family dysfunction, across multiple subsystems, represents a driving force in the progression of child internalizing symptoms. PMID:25790794

Decline in the Quality of Family Relationships Predicts Escalation in Children's Internalizing Symptoms from Middle to Late Childhood.

PubMed

Brock, Rebecca L; Kochanska, Grazyna

2015-10-01

An integration of family systems perspectives with developmental psychopathology provides a framework for examining the complex interplay between family processes and developmental trajectories of child psychopathology over time. In a community sample of 98 families, we investigated the evolution of family relationships, across multiple subsystems of the family (i.e., interparental, mother-child, father-child), and the impact of these changing family dynamics on developmental trajectories of child internalizing symptoms over 6 years, from preschool age to pre-adolescence. Parent-child relationship quality was observed during lengthy sessions, consisting of multiple naturalistic, carefully scripted contexts. Each parent completed reports about interparental relationship satisfaction and child internalizing symptoms. To the extent that mothers experienced a steeper decline in interparental relationship satisfaction over time, children developed internalizing symptoms at a faster rate. Further, symptoms escalated at a faster rate to the extent that negative mother-child relationship quality increased (more negative affect expressed by both mother and child, greater maternal power assertion) and positive mother-child relationship quality decreased (less positive affect expressed by both mother and child, less warmth and positive reciprocity). Time-lagged growth curve analyses established temporal precedence such that decline in family relationships preceded escalation in child internalizing symptoms. Results suggest that family dysfunction, across multiple subsystems, represents a driving force in the progression of child internalizing symptoms.

In Galápagos … and Uncomfortable with Evolution

ERIC Educational Resources Information Center

Cotner, Sehoya; Graczyk, Hannah; Rodríguez Garcia, José Luis; Moore, Randy

2016-01-01

In June 2013, the third World Evolution Summit convened on San Cristóbal, hosting scientists from around the world (Paz-y-Miño-C and Espinosa 2013)--neither the first nor likely the last gathering of biologists on these remote islands. Clearly, both locals and an international audience perceive Galápagos as figuring prominently in discourse about…

Abstracts for the International Conference on Asteroids, Comets, Meteors 1991

NASA Technical Reports Server (NTRS)

1991-01-01

Topics addressed include: chemical abundances; asteroidal belt evolution; sources of meteors and meteorites; cometary spectroscopy; gas diffusion; mathematical models; cometary nuclei; cratering records; imaging techniques; cometary composition; asteroid classification; radio telescopes and spectroscopy; magnetic fields; cosmogony; IUE observations; orbital distribution of asteroids, comets, and meteors; solar wind effects; computerized simulation; infrared remote sensing; optical properties; and orbital evolution.

USSR Report, International Affairs.

DTIC Science & Technology

1986-09-22

evolution ; by the beginning of the imperialist epoch they were not colonies as a rule, but they were lagging behind in their development and for...Metis population) and resource potential; they have undergone an extensive evolution from patriarchy to capitalist modernization deformed by foreign...territories of these countries for their own purposes—as "hotels," which attract foreign tourists , as locations for corporate and bank headquarters

What Are the Causes of Educational Inequality and of Its Evolution over Time in Europe? Evidence from PISA

ERIC Educational Resources Information Center

Oppedisano, Veruska; Turati, Gilberto

2015-01-01

This paper provides evidence on the sources of differences in inequality in educational scores and their evolution over time in four European countries. Using Programme for International Student Assessment data from the 2000 and the 2006 waves, the paper shows that inequality decreased in Germany and Spain (two "decentralised" schooling…

Analyzing the international exergy flow network of ferrous metal ores.

PubMed

Qi, Hai; An, Haizhong; Hao, Xiaoqing; Zhong, Weiqiong; Zhang, Yanbing

2014-01-01

This paper employs an un-weighted and weighted exergy network to study the properties of ferrous metal ores in countries worldwide and their evolution from 2002 to 2012. We find that there are few countries controlling most of the ferrous metal ore exports in terms of exergy and that the entire exergy flow network is becoming more heterogeneous though the addition of new nodes. The increasing of the average clustering coefficient indicates that the formation of an international exergy flow system and regional integration is improving. When we contrast the average out strength of exergy and the average out strength of currency, we find both similarities and differences. Prices are affected largely by human factors; thus, the growth rate of the average out strength of currency has fluctuated acutely in the eleven years from 2002 to 2012. Exergy is defined as the maximum work that can be extracted from a system and can reflect the true cost in the world, and this parameter fluctuates much less. Performing an analysis based on the two aspects of exergy and currency, we find that the network is becoming uneven.

Orbiting space debris: Dangers, measurement and mitigation

NASA Astrophysics Data System (ADS)

McNutt, Ross T.

1992-06-01

Space debris is a growing environmental problem. Accumulation of objects in earth orbit threatens space systems through the possibility of collisions and runaway debris multiplication. The amount of debris in orbit is uncertain due to the lack of information on the population of debris between 1 and 10 centimeters diameter. Collisions with debris even smaller than 1 cm can be catastrophic due to the high orbital velocities involved. Research efforts are under way at NASA, United States Space Command and the Air Force Phillips Laboratory to detect and catalog the debris population in near-earth space. Current international and national laws are inadequate to control the proliferation of space debris. Space debris is a serious problem with large economic, military, technical and diplomatic components. Actions need to be taken now to: determine the full extent of the orbital debris problem; accurately predict the future evolution of the debris population; decide the extent of the debris mitigation procedures required; implement these policies on a global basis via an international treaty. Action must be initiated now, before the loss of critical space systems such as the space shuttle or the space station.

Analyzing the International Exergy Flow Network of Ferrous Metal Ores

PubMed Central

Qi, Hai; An, Haizhong; Hao, Xiaoqing; Zhong, Weiqiong; Zhang, Yanbing

2014-01-01

This paper employs an un-weighted and weighted exergy network to study the properties of ferrous metal ores in countries worldwide and their evolution from 2002 to 2012. We find that there are few countries controlling most of the ferrous metal ore exports in terms of exergy and that the entire exergy flow network is becoming more heterogeneous though the addition of new nodes. The increasing of the average clustering coefficient indicates that the formation of an international exergy flow system and regional integration is improving. When we contrast the average out strength of exergy and the average out strength of currency, we find both similarities and differences. Prices are affected largely by human factors; thus, the growth rate of the average out strength of currency has fluctuated acutely in the eleven years from 2002 to 2012. Exergy is defined as the maximum work that can be extracted from a system and can reflect the true cost in the world, and this parameter fluctuates much less. Performing an analysis based on the two aspects of exergy and currency, we find that the network is becoming uneven. PMID:25188407

Influence of heating rate on the condensational instability. [in outer layers of solar atmosphere

NASA Technical Reports Server (NTRS)

Dahlburg, R. B.; Mariska, J. T.

1988-01-01

Analysis and numerical simulation are used to determine the effect that various heating rates have on the linear and nonlinear evolution of a typical plasma within a solar magnetic flux tube subject to the condensational instability. It is found that linear stability depends strongly on the heating rate. The results of numerical simulations of the nonlinear evolution of the condensational instability in a solar magnetic flux tube are presented. Different heating rates lead to quite different nonlinear evolutions, as evidenced by the behavior of the global internal energy.

Multiscale Modeling of Human-Water Interactions: The Role of Time-Scales

NASA Astrophysics Data System (ADS)

Bloeschl, G.; Sivapalan, M.

2015-12-01

Much of the interest in hydrological modeling in the past decades revolved around resolving spatial variability. With the rapid changes brought about by human impacts on the hydrologic cycle, there is now an increasing need to refocus on time dependency. We present a co-evolutionary view of hydrologic systems, in which every part of the system including human systems, co-evolve, albeit at different rates. The resulting coupled human-nature system is framed as a dynamical system, characterized by interactions of fast and slow time scales and feedbacks between environmental and social processes. This gives rise to emergent phenomena such as the levee effect, adaptation to change and system collapse due to resource depletion. Changing human values play a key role in the emergence of these phenomena and should therefore be considered as internal to the system in a dynamic way. The co-evolutionary approach differs from the traditional view of water resource systems analysis as it allows for path dependence, multiple equilibria, lock-in situations and emergent phenomena. The approach may assist strategic water management for long time scales through facilitating stakeholder participation, exploring the possibility space of alternative futures, and helping to synthesise the observed dynamics of different case studies. Future research opportunities include the study of how changes in human values are connected to human-water interactions, historical analyses of trajectories of system co-evolution in individual places and comparative analyses of contrasting human-water systems in different climate and socio-economic settings. Reference Sivapalan, M. and G. Blöschl (2015) Time Scale Interactions and the Co-evolution of Humans and Water. Water Resour. Res., 51, in press.

The evolution of icy satellite interiors and surfaces

NASA Technical Reports Server (NTRS)

Consolmagno, G. J.; Lewis, J. S.

1978-01-01

The results obtained by Consolmagno (1975) with regard to the interiors of the smaller icy satellites are presented and the evolution of the surfaces of these objects in the light of the considered models is discussed. In the discussion the icy satellites are divided into two groups. Those with radii larger than 1000 km are composed primarily of high-pressure phases of ice. In the case of satellites of this group, internal heating may produce significant melting and solid-state convection may not be important. Those satellites with radii less than 1000 km will be composed primarily of ice I and rock. They will not significantly melt and internal convection is likely to be important.

Overview of international remote sensing through 2007

NASA Astrophysics Data System (ADS)

Glackin, David L.

1997-12-01

The field of Earth remote sensing is evolving from one that contains purely governmental and military standalone systems of high complexity and expense to one that includes an increasing number of commercial systems, focused missions using small satellites, and systems of lower complexity and cost. The evolution of the field from 1980 - 2007 is summarized in this paper, with emphasis on the rapid changes of international scope that are taking place in 1997 which will shape the future of the field. As of three years ago, seven counties had built and flown free-flying earth observation satellite systems. Projections are for the number of countries operating such systems to approximately double by three years from now. Rapid changes are taking place in terms of spatial resolution, spectral resolution, proliferation of small satellites, ocean color, commercialization and privatization. Several fully commercial high-resolution systems will be launched over the next three years. Partly commercial synthetic aperture radar (SAR) systems became a reality with the launch of Radarsat in 1995. Only a handful of small satellite remote sensing missions have been launched to date, while a large number will be launched over the next few years, including minisats from Australia, Brazil, Israel, Italy, South Korea, Taiwan, Thailand, and the USA, as well as microsats from many countries including Malaysia, Pakistan and South Africa. Systems with far greater spectral resolution will also become a reality as hyperspectral instruments are launched. In 1997, we truly stand on the cusp of tremendous change in the burgeoning field of Earth remote sensing.

On the Importance of Very Light Internally Subsonic AGN Jets in Radio-mode AGN Feedback

NASA Astrophysics Data System (ADS)

Guo, Fulai

2016-07-01

Radio-mode active galactic nucleus (AGN) feedback plays a key role in the evolution of galaxy groups and clusters. Its physical origin lies in the kiloparsec-scale interaction of AGN jets with the intracluster medium. Large-scale jet simulations often initiate light internally supersonic jets with density contrast 0.01 < η < 1. Here we argue for the first time for the importance of very light (η < 0.01) internally subsonic jets. We investigated the shapes of young X-ray cavities produced in a suite of hydrodynamic simulations, and found that bottom-wide cavities are always produced by internally subsonic jets, while internally supersonic jets inflate cylindrical, center-wide, or top-wide cavities. We found examples of real cavities with shapes analogous to those inflated in our simulations by internally subsonic and internally supersonic jets, suggesting a dichotomy of AGN jets according to their internal Mach numbers. We further studied the long-term cavity evolution, and found that old cavities resulted from light jets spread along the jet direction, while those produced by very light jets are significantly elongated along the perpendicular direction. The northwestern ghost cavity in Perseus is pancake shaped, providing tentative evidence for the existence of very light jets. Our simulations show that very light internally subsonic jets decelerate faster and rise much slower in the intracluster medium than light internally supersonic jets, possibly depositing a larger fraction of jet energy to cluster cores and alleviating the problem of low coupling efficiencies found previously. The internal Mach number points to the jet’s energy content, and internally subsonic jets are energetically dominated by non-kinetic energy, such as thermal energy, cosmic rays, or magnetic fields.

ON THE IMPORTANCE OF VERY LIGHT INTERNALLY SUBSONIC AGN JETS IN RADIO-MODE AGN FEEDBACK

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guo, Fulai, E-mail: fulai@shao.ac.cn

Radio-mode active galactic nucleus (AGN) feedback plays a key role in the evolution of galaxy groups and clusters. Its physical origin lies in the kiloparsec-scale interaction of AGN jets with the intracluster medium. Large-scale jet simulations often initiate light internally supersonic jets with density contrast 0.01 < η < 1. Here we argue for the first time for the importance of very light ( η < 0.01) internally subsonic jets. We investigated the shapes of young X-ray cavities produced in a suite of hydrodynamic simulations, and found that bottom-wide cavities are always produced by internally subsonic jets, while internally supersonicmore » jets inflate cylindrical, center-wide, or top-wide cavities. We found examples of real cavities with shapes analogous to those inflated in our simulations by internally subsonic and internally supersonic jets, suggesting a dichotomy of AGN jets according to their internal Mach numbers. We further studied the long-term cavity evolution, and found that old cavities resulted from light jets spread along the jet direction, while those produced by very light jets are significantly elongated along the perpendicular direction. The northwestern ghost cavity in Perseus is pancake shaped, providing tentative evidence for the existence of very light jets. Our simulations show that very light internally subsonic jets decelerate faster and rise much slower in the intracluster medium than light internally supersonic jets, possibly depositing a larger fraction of jet energy to cluster cores and alleviating the problem of low coupling efficiencies found previously. The internal Mach number points to the jet’s energy content, and internally subsonic jets are energetically dominated by non-kinetic energy, such as thermal energy, cosmic rays, or magnetic fields.« less

Challenges to polycentric governance of an international development project tackling land degradation in Swaziland.

PubMed

Orchard, Steven E; Stringer, Lindsay C

2016-11-01

To effectively address the drivers and impacts of land degradation requires polycentric governance systems that facilitate international development projects (IDPs). This paper analyses an IDP aiming to reduce land degradation in Swaziland. A longitudinal-style qualitative approach draws on repeat household surveys, semi-structured interviews and focus groups. We aim to identify the changes that have taken place since the departure of the IDP funders, and the subsequent dynamics between stakeholders. We: (1) chart the evolution of the institutional structures and processes of the IDP; and (2) assess community perceptions of IDP outcomes. Lack of meaningful participation at various stages of the PMC caused the project to lose momentum following the departure of the funders. We discuss these findings in relation to a polycentric approach, and identify how multi-stakeholder IDP can be facilitated as part of wider polycentric governance approaches to inform policies to combat land degradation within Swaziland and more widely.

The Influence of Microbiology on Spacecraft Design and Controls: A Historical Perspective of the Shuttle and International Space Station Programs

NASA Technical Reports Server (NTRS)

Castro, Victoria A.; Bruce, Rebekah J.; Ott, C. Mark; Pierson, D. L.

2006-01-01

For over 40 years, NASA has been putting humans safely into space in part by minimizing microbial risks to crew members. Success of the program to minimize such risks has resulted from a combination of engineering and design controls as well as active monitoring of the crew, food, water, hardware, and spacecraft interior. The evolution of engineering and design controls is exemplified by the implementation of HEPA filters for air treatment, antimicrobial surface materials, and the disinfection regimen currently used on board the International Space Station. Data from spaceflight missions confirm the effectiveness of current measures; however, fluctuations in microbial concentrations and trends in contamination events suggest the need for continued diligence in monitoring and evaluation as well as further improvements in engineering systems. The knowledge of microbial controls and monitoring from assessments of past missions will be critical in driving the design of future spacecraft.

Evolution of damage during deformation in porous granular materials (Louis Néel Medal Lecture)

NASA Astrophysics Data System (ADS)

Main, Ian

2014-05-01

'Crackling noise' occurs in a wide variety of systems that respond to external forcing in an intermittent way, leading to sudden bursts of energy release similar to those heard when crunching up a piece of paper or listening to a fire. In mineral magnetism ('Barkhausen') crackling noise occurs due to sudden changes in the size and orientation of microscopic ferromagnetic domains when the external magnetic field is changed. In rock physics sudden changes in internal stress associated with microscopically brittle failure events lead to acoustic emissions that can be recorded on the sample boundary, and used to infer the state of internal damage. Crackling noise is inherently stochastic, but the population of events often exhibits remarkably robust scaling properties, in terms of the source area, duration, energy, and in the waiting time between events. Here I describe how these scaling properties emerge and evolve spontaneously in a fully-dynamic discrete element model of sedimentary rocks subject to uniaxial compression at a constant strain rate. The discrete elements have structural disorder similar to that of a real rock, and this is the only source of heterogeneity. Despite the stationary loading and the lack of any time-dependent weakening processes, the results are all characterized by emergent power law distributions over a broad range of scales, in agreement with experimental observation. As deformation evolves, the scaling exponents change systematically in a way that is similar to the evolution of damage in experiments on real sedimentary rocks. The potential for real-time failure forecasting is examined by using synthetic and real data from laboratory tests and prior to volcanic eruptions. The combination of non-linearity and an irreducible stochastic component leads to significant variations in the precision and accuracy of the forecast failure time, leading to a significant proportion of 'false alarms' (forecast too early) and 'missed events' (forecast too late), as well as an over-optimistic assessments of forecasting power and quality when the failure time is known (the 'benefit of hindsight'). The evolution becomes progressively more complex, and the forecasting power diminishes, in going from ideal synthetics to controlled laboratory tests to open natural systems at larger scales in space and time.

MONTE CARLO POPULATION SYNTHESIS OF POST-COMMON-ENVELOPE WHITE DWARF BINARIES AND TYPE Ia SUPERNOVA RATE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ablimit, Iminhaji; Maeda, Keiichi; Li, Xiang-Dong

Binary population synthesis (BPS) studies provide a comprehensive way to understand the evolution of binaries and their end products. Close white dwarf (WD) binaries have crucial characteristics for examining the influence of unresolved physical parameters on binary evolution. In this paper, we perform Monte Carlo BPS simulations, investigating the population of WD/main-sequence (WD/MS) binaries and double WD binaries using a publicly available binary star evolution code under 37 different assumptions for key physical processes and binary initial conditions. We considered different combinations of the binding energy parameter ( λ {sub g}: considering gravitational energy only; λ {sub b}: considering bothmore » gravitational energy and internal energy; and λ {sub e}: considering gravitational energy, internal energy, and entropy of the envelope, with values derived from the MESA code), CE efficiency, critical mass ratio, initial primary mass function, and metallicity. We find that a larger number of post-CE WD/MS binaries in tight orbits are formed when the binding energy parameters are set by λ {sub e} than in those cases where other prescriptions are adopted. We also determine the effects of the other input parameters on the orbital periods and mass distributions of post-CE WD/MS binaries. As they contain at least one CO WD, double WD systems that evolved from WD/MS binaries may explode as type Ia supernovae (SNe Ia) via merging. In this work, we also investigate the frequency of two WD mergers and compare it to the SNe Ia rate. The calculated Galactic SNe Ia rate with λ = λ {sub e} is comparable to the observed SNe Ia rate, ∼8.2 × 10{sup 5} yr{sup 1} – ∼4 × 10{sup 3} yr{sup 1} depending on the other BPS parameters, if a DD system does not require a mass ratio higher than ∼0.8 to become an SNe Ia. On the other hand, a violent merger scenario, which requires the combined mass of two CO WDs ≥ 1.6 M {sub ⊙} and a mass ratio >0.8, results in a much lower SNe Ia rate than is observed.« less

The isotopic and chemical evolution of planets: Mars as a missing link

NASA Technical Reports Server (NTRS)

Depaolo, D. J.

1988-01-01

The study of planetary bodies has advanced to a stage where it is possible to contemplate general models for the chemical and physical evolution of planetary interiors, which might be referred to as UMPES (Unified Models of Planetary Evolution and Structure). UMPES would be able to predict the internal evolution and structure of a planet given certain input parameters such as mass, distance from the sun, and a time scale for accretion. Such models are highly dependent on natural observations because the basic material properties of planetary interiors, and the processes that take place during the evolution of planets are imperfectly understood. The idea of UMPES was particularly unrealistic when the only information available was from the earth. However, advances have been made in the understanding of the general aspects of planetary evolution now that there is geochemical and petrological data available for the moon and for meteorites.

Internal structures and dating of non-sulphide Zn deposits using rock magnetism: insights from the Moroccan High Atlas

NASA Astrophysics Data System (ADS)

Charles, Nicolas; Choulet, Flavien; Sizaret, Stanislas; Chen, Yan; Barbanson, Luc; Ennaciri, Aomar; Badra, Lakhlifi; Branquet, Yannick

2016-01-01

The renewal of interest in Zn-Pb non-sulphide ores has been induced by mineral processing improvement and leads to new exploration and mining projects in the world. Although the mineralogy is often precisely known, and despite several studies linking ore deposition to regional tectonics, absolute dating of non-sulphide stages is rare and structure of ore bodies was largely disregarded. Geochronological data from non-sulphide ores are essential to timely constrain alteration episodes and to insert supergene ore genesis in the climate and tectonic evolution of the metallogenic province. The access to internal organization of ore could reveal post-mineralization episodes related to supergene evolution. Thus, a rock magnetism study combining anisotropy of magnetic susceptibility (AMS) and palaeomagnetism was performed on four non-sulphide deposits from the Moroccan High Atlas. AMS generally shows similar horizontal magnetic fabrics for ores and the clayey and carbonaceous internal sediments filling karstic cavities. The palaeomagnetic directions of ores and internal sediments are compatible, and the calculated poles are consistent with the last 30 Ma of the Africa apparent polar wander path, with an upper age at 0.78 Ma. The proposed three-step scenario is placed within the evolution of the Moroccan High Atlas belt. Deposition of primary sulphides is contemporaneous with opening of the Tethyan and Atlantic oceans. During the Tertiary, intracontinental deformation gave rise to the High Atlas fold-and-thrust belt and to regional uplift. Finally, Zn-Pb sulphides hosted in carbonates experienced oxidation under an arid climate to form karst-related Zn-Pb non-sulphide ores. These promising results pave the way for an efficient method to constrain the internal fabrics and age of Zn supergene deposits.

Eruptive stratigraphy of the Tatara-San Pedro complex, 36°S, sourthern volcanic zone, Chilean Andes: reconstruction method and implications for magma evolution at long-lived arc volcanic centers

USGS Publications Warehouse

Dungan, M.A.; Wulff, A.; Thompson, R.

2001-01-01

The Quaternary Tatara-San Pedro volcanic complex (36°S, Chilean Andes) comprises eight or more unconformity-bound volcanic sequences, representing variably preserved erosional remnants of volcanic centers generated during 930 ky of activity. The internal eruptive histories of several dominantly mafic to intermediate sequences have been reconstructed, on the basis of correlations of whole-rock major and trace element chemistry of flows between multiple sampled sections, but with critical contributions from photogrammetric, geochronologic, and paleomagnetic data. Many groups of flows representing discrete eruptive events define internal variation trends that reflect extrusion of heterogeneous or rapidly evolving magna batches from conduit-reservoir systems in which open-system processes typically played a large role. Long-term progressive evolution trends are extremely rare and the magma compositions of successive eruptive events rarely lie on precisely the same differentiation trend, even where they have evolved from similar parent magmas by similar processes. These observations are not consistent with magma differentiation in large long-lived reservoirs, but they may be accommodated by diverse interactions between newly arrived magma inputs and multiple resident pockets of evolved magma and / or crystal mush residing in conduit-dominated subvolcanic reservoirs. Without constraints provided by the reconstructed stratigraphic relations, the framework for petrologic modeling would be far different. A well-established eruptive stratigraphy may provide independent constraints on the petrologic processes involved in magma evolution-simply on the basis of the specific order in which diverse, broadly cogenetic magmas have been erupted. The Tatara-San Pedro complex includes lavas ranging from primitive basalt to high-SiO2 rhyolite, and although the dominant erupted magma type was basaltic andesite ( 52-55 wt % SiO2) each sequence is characterized by unique proportions of mafic, intermediate, and silicic eruptive products. Intermediate lava compositions also record different evolution paths, both within and between sequences. No systematic long-term pattern is evident from comparisons at the level of sequences. The considerable diversity of mafic and evolved magmas of the Tatara-San Pedro complex bears on interpretations of regional geochemical trends. The variable role of open-system processes in shaping the compositions of evolved Tatara-San Pedro complex magmas, and even some basaltic magmas, leads to the conclusion that addressing problems such as are magma genesis and elemental fluxes through subduction zones on the basis of averaged or regressed reconnaissance geochemical datasets is a tenuous exercise. Such compositional indices are highly instructive for identifying broad regional trends and first-order problems, but they should be used with extreme caution in attempts to quantify processes and magma sources, including crustal components, implicated in these trends.

Evolution processes of the corrosion behavior and structural characteristics of plasma electrolytic oxidation coatings on AZ31 magnesium alloy

NASA Astrophysics Data System (ADS)

Chen, Dong; Wang, Ruiqiang; Huang, Zhiquan; Wu, Yekang; Zhang, Yi; Wu, Guorui; Li, Dalong; Guo, Changhong; Jiang, Guirong; Yu, Shengxue; Shen, Dejiu; Nash, Philip

2018-03-01

Evolution processes of the corrosion behavior and structural characteristics of the plasma electrolytic oxidation (PEO) coated AZ31 magnesium alloy were investigated by using scanning electron microscope (SEM) equipped with energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), potentio-dynamic polarization curves and electrochemical impedance spectroscopy (EIS) measurements. Detached coating samples were fabricated by an electrochemical method and more details of the internal micro-structure of coatings were clearly observed on the fractured cross-section morphologies of the samples compared to general polished cross-section morphologies. Evolution mechanisms of the coating corrosion behavior in relation to the evolution of micro-structural characteristics were discussed in detail.

Shape Evolution of Detached Bridgman Crystals Grown in Microgravity

NASA Technical Reports Server (NTRS)

Volz, M. P.; Mazuruk, K.

2015-01-01

A theory describing the shape evolution of detached Bridgman crystals in microgravity has been developed. A starting crystal of initial radius r0 will evolve to one of the following states: Stable detached gap; Attachment to the crucible wall; Meniscus collapse. Only crystals where alpha plus omega is great than 180 degrees will achieve stable detached growth in microgravity. Results of the crystal shape evolution theory are consistent with predictions of the dynamic stability of crystallization (Tatarchenko, Shaped Crystal Growth, Kluwer, 1993). Tests of transient crystal evolution are planned for ICESAGE, a series of Ge and GeSi crystal growth experiments planned to be conducted on the International Space Station (ISS).

Continuous "in vitro" Evolution of a Ribozyme Ligase: A Model Experiment for the Evolution of a Biomolecule

ERIC Educational Resources Information Center

Ledbetter, Michael P.; Hwang, Tony W.; Stovall, Gwendolyn M.; Ellington, Andrew D.

2013-01-01

Evolution is a defining criterion of life and is central to understanding biological systems. However, the timescale of evolutionary shifts in phenotype limits most classroom evolution experiments to simple probability simulations. "In vitro" directed evolution (IVDE) frequently serves as a model system for the study of Darwinian…

The evolution of the plant genome-to-morphology auxin circuit.

PubMed

Kutschera, Ulrich; Niklas, Karl J

2016-09-01

In his Generelle Morphologie der Organismen (1866), 150 years ago, Ernst Haeckel (1834-1919) combined developmental patterns in animals with the concept of organismic evolution, and 50 years ago, a new era of plant research started when focus shifted from crop species (sunflower, maize etc.) to thale cress (Arabidopsis thaliana) as a model organism. In this contribution, we outline the general principles of developmental evolutionary biology sensu Haeckel and describe the evolutionary genome-to-morphology-plant hormone auxin (IAA, indole-3-acetic acid)-circuit with reference to other phytohormones and a focus on land plants (embryophytes) plus associated epiphytic microbes. Our primary conclusion is that a system-wide approach is required to truly understand the ontogeny of any organism, because development proceeds according to signal pathways that integrate and respond to external as well as internal stimuli. We also discuss IAA-regulated embryology in A. thaliana and epigenetic phenomena in the gametophyte development, and outline how these processes are connected to the seminal work of Ernst Haeckel.

Evolving autonomous learning in cognitive networks.

PubMed

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.

Shear History Extensional Rheology Experiment: A Proposed ISS Experiment

NASA Technical Reports Server (NTRS)

Hall, Nancy R.; Logsdon, Kirk A.; Magee, Kevin S.

2007-01-01

The Shear History Extensional Rheology Experiment (SHERE) is a proposed International Space Station (ISS) glovebox experiment designed to study the effect of preshear on the transient evolution of the microstructure and viscoelastic tensile stresses for monodisperse dilute polymer solutions. Collectively referred to as Boger fluids, these polymer solutions have become a popular choice for rheological studies of non-Newtonian fluids and are the non-Newtonian fluid used in this experiment. The SHERE hardware consists of the Rheometer, Camera Arm, Interface Box, Cabling, Keyboard, Tool Box, Fluid Modules, and Stowage Tray. Each component will be described in detail in this paper. In the area of space exploration, the development of in-situ fabrication and repair technology represents a critical element in evolution of autonomous exploration capability. SHERE has the capability to provide data for engineering design tools needed for polymer parts manufacturing systems to ensure their rheological properties have not been impacted in the variable gravity environment and this will be briefly addressed.

Evolution of drug reimbursement in Canada: the Pan-Canadian Pharmaceutical Alliance for new drugs.

PubMed

Husereau, Don; Dempster, William; Blanchard, Adrienne; Chambers, Johanne

2014-12-01

Canada has a unique system of public drug coverage and reimbursement characterized by a centralized review agency that makes funding recommendations along with decentralized authority for delivering health care across 10 provinces and three territories. There has been a significant increase in price negotiation for new pharmaceuticals in the past 10 years, first by individual provinces and now through a collective price negotiation process called the "Pan-Canadian Pharmaceutical Alliance." As of February 2014, the Pan-Canadian Pharmaceutical Alliance has already completed 32 negotiations despite still being in a formative stage; it is anticipated that a formal process will be developed in the coming year. In this article, we describe the evolution of price negotiation in Canada and identify several opportunities for improvement of the current process, including the incorporation of economic considerations into price negotiation. Copyright © 2014 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

SRB/SLEEC (Solid Rocket Booster/Shingle Lap Extendible Exit Cone) feasibility study, volume 2. Appendix A: Design study for a SLEEC actuation system

NASA Technical Reports Server (NTRS)

Thompson, D. S.

1986-01-01

The results are presented of a design feasibility study of a self-contained (powered) actuation system for a Shingle Lap Extendible Exit Cone (SLEEC) for Transportation System (STS). The evolution of the SLEEC actuation system design is reviewed, the final design concept is summarized, and the results of the detailed study of the final concept of the actuation system are treated. A conservative design using proven mechanical components was established as a major program priority. The final mechanical design has a very low development risk since the components, which consist of ballscrews, gearing, flexible shaft drives, and aircraft cables, have extensive aerospace applications and a history of proven reliability. The mathematical model studies have shown that little or no power is required to deploy the SLEEC actuation system because acceleration forces and internal pressure from the rocket plume provide the required energies. A speed control brake is incorporated in the design in order to control the rate of deployment.

Evolution of the 3-dimensional video system for facial motion analysis: ten years' experiences and recent developments.

PubMed

Tzou, Chieh-Han John; Pona, Igor; Placheta, Eva; Hold, Alina; Michaelidou, Maria; Artner, Nicole; Kropatsch, Walter; Gerber, Hans; Frey, Manfred

2012-08-01

Since the implementation of the computer-aided system for assessing facial palsy in 1999 by Frey et al (Plast Reconstr Surg. 1999;104:2032-2039), no similar system that can make an objective, three-dimensional, quantitative analysis of facial movements has been marketed. This system has been in routine use since its launch, and it has proven to be reliable, clinically applicable, and therapeutically accurate. With the cooperation of international partners, more than 200 patients were analyzed. Recent developments in computer vision--mostly in the area of generative face models, applying active--appearance models (and extensions), optical flow, and video-tracking-have been successfully incorporated to automate the prototype system. Further market-ready development and a business partner will be needed to enable the production of this system to enhance clinical methodology in diagnostic and prognostic accuracy as a personalized therapy concept, leading to better results and higher quality of life for patients with impaired facial function.

Solute mixing regulates heterogeneity of mineral precipitation in porous media: Effect of Solute Mixing on Precipitation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cil, Mehmet B.; Xie, Minwei; Packman, Aaron I.

Synchrotron X-ray microtomography was used to track the spatiotemporal evolution of mineral precipitation and the consequent alteration of the pore structure. Column experiments were conducted by injecting CaCl2 and NaHCO3 solutions into granular porous media either as a premixed supersaturated solution (external mixing) or as separate solutions that mixed within the specimen (internal mixing). The two mixing modes produced distinct mineral growth patterns. While internal mixing promoted transverse heterogeneity with precipitation at the mixing zone, external mixing favored relatively homogeneous precipitation along the flow direction. The impact of precipitation on pore water flow and permeability was assessed via 3-D flowmore » simulations, which indicated anisotropic permeability evolution for both mixing modes. Under both mixing modes, precipitation decreased the median pore size and increased the skewness of the pore size distribution. Such similar pore-scale evolution patterns suggest that the clogging of individual pores depends primarily on local supersaturation state and pore geometry.« less

The Molecular Basis of Evolution and Disease: A Cold War Alliance.

PubMed

Suárez-Díaz, Edna

2017-03-28

This paper extends previous arguments against the assumption that the study of variation at the molecular level was instigated with a view to solving an internal conflict between the balance and classical schools of population genetics. It does so by focusing on the intersection of basic research in protein chemistry and the molecular approach to disease with the enactment of global health campaigns during the Cold War period. The paper connects advances in research on protein structure and function as reflected in Christian Anfinsen's The molecular basis of evolution, with a political reading of Emilé Zuckerkandl and Linus Pauling's identification of molecular disease and evolution. Beyond atomic fallout, these advances constituted a rationale for the promotion of genetic surveys of human populations in the Third World, in connection with international health programs. Light is shed not only on the experimental roots of the molecular challenge but on the broader geopolitical context where the rising role of biomedicine and public health (particularly the malaria eradication campaigns) had an impact on evolutionary biology.

Coherent diffraction imaging of nanoscale strain evolution in a single crystal under high pressure

PubMed Central

Yang, Wenge; Huang, Xiaojing; Harder, Ross; Clark, Jesse N.; Robinson, Ian K.; Mao, Ho-kwang

2013-01-01

The evolution of morphology and internal strain under high pressure fundamentally alters the physical property, structural stability, phase transition and deformation mechanism of materials. Until now, only averaged strain distributions have been studied. Bragg coherent X-ray diffraction imaging is highly sensitive to the internal strain distribution of individual crystals but requires coherent illumination, which can be compromised by the complex high-pressure sample environment. Here we report the successful de-convolution of these effects with the recently developed mutual coherent function method to reveal the three-dimensional strain distribution inside a 400 nm gold single crystal during compression within a diamond-anvil cell. The three-dimensional morphology and evolution of the strain under pressures up to 6.4 GPa were obtained with better than 30 nm spatial resolution. In addition to providing a new approach for high-pressure nanotechnology and rheology studies, we draw fundamental conclusions about the origin of the anomalous compressibility of nanocrystals. PMID:23575684

Coherent diffraction imaging of nanoscale strain evolution in a single crystal under high pressure.

PubMed

Yang, Wenge; Huang, Xiaojing; Harder, Ross; Clark, Jesse N; Robinson, Ian K; Mao, Ho-kwang

2013-01-01

The evolution of morphology and internal strain under high pressure fundamentally alters the physical property, structural stability, phase transition and deformation mechanism of materials. Until now, only averaged strain distributions have been studied. Bragg coherent X-ray diffraction imaging is highly sensitive to the internal strain distribution of individual crystals but requires coherent illumination, which can be compromised by the complex high-pressure sample environment. Here we report the successful de-convolution of these effects with the recently developed mutual coherent function method to reveal the three-dimensional strain distribution inside a 400 nm gold single crystal during compression within a diamond-anvil cell. The three-dimensional morphology and evolution of the strain under pressures up to 6.4 GPa were obtained with better than 30 nm spatial resolution. In addition to providing a new approach for high-pressure nanotechnology and rheology studies, we draw fundamental conclusions about the origin of the anomalous compressibility of nanocrystals.

Towards a Global Service Registry for the World-Wide LHC Computing Grid

NASA Astrophysics Data System (ADS)

Field, Laurence; Alandes Pradillo, Maria; Di Girolamo, Alessandro

2014-06-01

The World-Wide LHC Computing Grid encompasses a set of heterogeneous information systems; from central portals such as the Open Science Grid's Information Management System and the Grid Operations Centre Database, to the WLCG information system, where the information sources are the Grid services themselves. Providing a consistent view of the information, which involves synchronising all these informations systems, is a challenging activity that has lead the LHC virtual organisations to create their own configuration databases. This experience, whereby each virtual organisation's configuration database interfaces with multiple information systems, has resulted in the duplication of effort, especially relating to the use of manual checks for the handling of inconsistencies. The Global Service Registry aims to address this issue by providing a centralised service that aggregates information from multiple information systems. It shows both information on registered resources (i.e. what should be there) and available resources (i.e. what is there). The main purpose is to simplify the synchronisation of the virtual organisation's own configuration databases, which are used for job submission and data management, through the provision of a single interface for obtaining all the information. By centralising the information, automated consistency and validation checks can be performed to improve the overall quality of information provided. Although internally the GLUE 2.0 information model is used for the purpose of integration, the Global Service Registry in not dependent on any particular information model for ingestion or dissemination. The intention is to allow the virtual organisation's configuration databases to be decoupled from the underlying information systems in a transparent way and hence simplify any possible future migration due to the evolution of those systems. This paper presents the Global Service Registry architecture, its advantages compared to the current situation and how it can support the evolution of information systems.

High-throughput sample processing and sample management; the functional evolution of classical cytogenetic assay towards automation.

PubMed

Ramakumar, Adarsh; Subramanian, Uma; Prasanna, Pataje G S

2015-11-01

High-throughput individual diagnostic dose assessment is essential for medical management of radiation-exposed subjects after a mass casualty. Cytogenetic assays such as the Dicentric Chromosome Assay (DCA) are recognized as the gold standard by international regulatory authorities. DCA is a multi-step and multi-day bioassay. DCA, as described in the IAEA manual, can be used to assess dose up to 4-6 weeks post-exposure quite accurately but throughput is still a major issue and automation is very essential. The throughput is limited, both in terms of sample preparation as well as analysis of chromosome aberrations. Thus, there is a need to design and develop novel solutions that could utilize extensive laboratory automation for sample preparation, and bioinformatics approaches for chromosome-aberration analysis to overcome throughput issues. We have transitioned the bench-based cytogenetic DCA to a coherent process performing high-throughput automated biodosimetry for individual dose assessment ensuring quality control (QC) and quality assurance (QA) aspects in accordance with international harmonized protocols. A Laboratory Information Management System (LIMS) is designed, implemented and adapted to manage increased sample processing capacity, develop and maintain standard operating procedures (SOP) for robotic instruments, avoid data transcription errors during processing, and automate analysis of chromosome-aberrations using an image analysis platform. Our efforts described in this paper intend to bridge the current technological gaps and enhance the potential application of DCA for a dose-based stratification of subjects following a mass casualty. This paper describes one such potential integrated automated laboratory system and functional evolution of the classical DCA towards increasing critically needed throughput. Published by Elsevier B.V.

Education for All and the New Development Compact

ERIC Educational Resources Information Center

Mundy, Karen

2006-01-01

Over the past decade, the achievement of universal primary education, under the somewhat misleading rubric of "Education for All" (EFA), has steadily built momentum in international forums as a focus for discussion and action. The present study looks critically at the evolution of consensus about EFA within the international community. The first…

The Approach to Equilibrium: Detailed Balance and the Master Equation

ERIC Educational Resources Information Center

Alexander, Millard H.; Hall, Gregory E.; Dagdigian, Paul J.

2011-01-01

The approach to the equilibrium (Boltzmann) distribution of populations of internal states of a molecule is governed by inelastic collisions in the gas phase and with surfaces. The set of differential equations governing the time evolution of the internal state populations is commonly called the master equation. An analytic solution to the master…

Evolution of Internal Quality Assurance at One University--A Case Study

ERIC Educational Resources Information Center

O'Sullivan, David

2017-01-01

Purpose: Quality assurance (QA) at one University has evolved over the past 15 years through emerging National and European standards, various leadership initiatives and through the engagement of key stakeholders in co-designing and implementing internal QA processes. In 2000, the QA process was focussed mainly on quality review (QR) that involved…

The role of internal dynamics in the coherent evolution of indirect excitons

NASA Astrophysics Data System (ADS)

Grasselli, Federico; Bertoni, Andrea; Goldoni, Guido

2017-08-01

We study the time-dependent quantum scattering of a spatially indirect exciton by an external potential, taking fully into account the relative quantum dynamics of the electron-hole (e-h) pair. Exact calculations for an e-h wave packet show that transfer of energy between centre-of-mass (c.m.) and relative degrees of freedom may result in a genuine correction to the evolution during the scattering and eventually at asymptotic times. We show in experimentally relevant regimes and device configurations, that transmission resonances, tunnelling probabilities, diffraction patterns and wave packet fragmentation of indirect excitons are largely determined by the internal dynamics, and could not be reproduced by point-like dipole models or mean-field calculations. We show that a properly-designed local self-energy potential to be added to the c.m. Hamiltonian embeds the effects of the c.m.-internal motion correlation at a small fraction of the computation load needed for full-propagation calculations. The explicit form of this self-energy emphasises the dominant role of internal virtual transitions in determining scattering coefficients of indirect excitons.

Lessons Learned from the Deployment and Integration of a Microwave Sounder Based Tropical Cyclone Intensity and Surface Wind Estimation Algorithm into NOAA/NESDIS Satellite Product Operations

NASA Astrophysics Data System (ADS)

Longmore, S. P.; Knaff, J. A.; Schumacher, A.; Dostalek, J.; DeMaria, R.; Chirokova, G.; Demaria, M.; Powell, D. C.; Sigmund, A.; Yu, W.

2014-12-01

The Colorado State University (CSU) Cooperative Institute for Research in the Atmosphere (CIRA) has recently deployed a tropical cyclone (TC) intensity and surface wind radii estimation algorithm that utilizes Suomi National Polar-orbiting Partnership (S-NPP) satellite Advanced Technology Microwave Sounder (ATMS) and Advanced Microwave Sounding Unit (AMSU) from the NOAA18, NOAA19 and METOPA polar orbiting satellites for testing, integration and operations for the Product System Development and Implementation (PSDI) projects at NOAA's National Environmental Satellite, Data, and Information Service (NESDIS). This presentation discusses the evolution of the CIRA NPP/AMSU TC algorithms internally at CIRA and its migration and integration into the NOAA Data Exploitation (NDE) development and testing frameworks. The discussion will focus on 1) the development cycle of internal NPP/AMSU TC algorithms components by scientists and software engineers, 2) the exchange of these components into the NPP/AMSU TC software systems using the subversion version control system and other exchange methods, 3) testing, debugging and integration of the NPP/AMSU TC systems both at CIRA/NESDIS and 4) the update cycle of new releases through continuous integration. Lastly, a discussion of the methods that were effective and those that need revision will be detailed for the next iteration of the NPP/AMSU TC system.

NASA'S Solar System Exploration Research Virtual Institute: An international approach toward bringing science and human exploration together for mutual benefit

NASA Astrophysics Data System (ADS)

Schmidt, Gregory

2016-07-01

The NASA Solar System Exploration Research Virtual Institute (SSERVI) is a virtual institute focused on research at the intersection of science and explora-tion, training the next generation of lunar scientists, and community development. The institute is a hub for opportunities that engage the larger scientific and exploration communities in order to form new interdis-ciplinary, research-focused collaborations. Its relative-ly large domestic teams work together along with in-ternational partners in both traditional and virtual set-tings to bring disparate approaches together for mutual benefit. This talk will describe the research efforts of the nine domestic teams that constitute the U.S. com-plement of the Institute and how it is engaging the in-ternational science and exploration communities through workshops, conferences, online seminars and classes, student exchange programs and internships. The Institute is centered on the scientific aspects of exploration as they pertain to the Moon, Near Earth Asteroids (NEAs) and the moons of Mars. It focuses on interdisciplinary, exploration-related science cen-tered around all airless bodies targeted as potential human destinations. Areas of study reported here will represent the broad spectrum of lunar, NEA, and Mar-tian moon sciences encompassing investigations of the surface, interior, exosphere, and near-space environ-ments as well as science uniquely enabled from these bodies. The technical focus ranges from investigations of plasma physics, geology/geochemistry, technology integration, solar system origins/evolution, regolith geotechnical properties, analogues, volatiles, ISRU and exploration potential of the target bodies. SSERVI enhances the widening knowledgebase of planetary research by acting as a bridge between several differ-ent groups and bringing together researchers from the scientific and exploration communities, multiple disci-plines across the full range of planetary sciences, and domestic and international communities and partner-ships.

[The economics of health care in developing countries: what the fight against the AIDS epidemics has changed].

PubMed

Moatti, Jean Paul

2008-12-01

Since the start of the new century, development aid targeted on health care has seen an unprecedented rise, driven by the fight against AIDS. This article shows how this struggle has been accompanied with a renewal of the economic paradigms governing international action in favour of health care in developing countries: the idea that an improvement in health care constitutes an unavoidable prerequisite to macroeconomic growth, rather than a consequence; the insistence on the founding of mechanisms for health insurance to finance the costs of health care, rather than covering the costs at the point of use by the health care users; a concern to impose price differentials for access to medicine in developing countries, and to introduce flexibility in the regulation of international intellectual property law; the priority to vertical programmes targeted on certain illnesses, thought to act as levers for a global reinforcement of health care systems. This article discusses the pertinence of these new paradigms in light of the evolution of the AIDS/HIV epidemic, and the international context.

The evolution of inducible defence.

PubMed

Harvell, C D

1990-01-01

Defences against parasites are characterized by inducible, amplifiable responses, often with a memory component. Inducible defences with similar properties are common in a variety of other types of interactions, for example many aquatic invertebrates produce inducible structural defences against their predators and competitors. Most inducible defences have the following properties: (1) a threshold of activation; (2) an amplification of response with increasing stimulus; (3) a memory component. Specificity, amplification and memory are the basis for defining a defence as 'immune' (Klein, 1982), and these properties are present in both the vertebrate and invertebrate internal defence responses to pathogens. Invertebrates differ in the absence of immunoglobulins and therefore in reduced specificity. Although the reduced specificity of invertebrate internal defence systems is often viewed as proof of their 'primitiveness', the differences in defence systems of vertebrates and invertebrates may be more related to their respective selection regimes than to phylogeny. The syngeneic recognition system of vertebrates functions to recognize small departures from self, such as would arise from neoplasia. Are vertebrates under more intense selection from neoplasia, perhaps due to a greater incidence of hormonal imbalance or hypersensitivity reactions? The invertebrate internal defence systems are all less discriminating than the vertebrate, but there are marked differences in degree of discrimination depending on whether the group is colonial or not. Even the phyla of colonial animals with quite simple body plans, the sponges and cnidarians, have a more discriminating recognition system than the phyla of solitary animals with more complex body plans, such as the molluscs and arthropods. The primary effectors of all invertebrate responses to parasites are encapsulation and phagocytosis, although in some phyla there are specific antibacterial proteins than can also be induced.(ABSTRACT TRUNCATED AT 250 WORDS)

Systems resilience : a new analytical framework for nuclear nonproliferation.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pregenzer, Arian Leigh

2011-12-01

This paper introduces the concept of systems resilience as a new framework for thinking about the future of nonproliferation. Resilience refers to the ability of a system to maintain its vital functions in the face of continuous and unpredictable change. The nonproliferation regime can be viewed as a complex system, and key themes from the literature on systems resilience can be applied to the nonproliferation system. Most existing nonproliferation strategies are aimed at stability rather than resilience, and the current nonproliferation system may be over-constrained by the cumulative evolution of strategies, increasing its vulnerability to collapse. The resilience of themore » nonproliferation system can be enhanced by diversifying nonproliferation strategies to include general international capabilities to respond to proliferation and focusing more attention on reducing the motivation to acquire nuclear weapons in the first place. Ideas for future research, include understanding unintended consequences and feedbacks among nonproliferation strategies, developing methodologies for measuring the resilience of the nonproliferation system, and accounting for interactions of the nonproliferation system with other systems on larger and smaller scales.« less

Parabolic replicator dynamics and the principle of minimum Tsallis information gain

PubMed Central

2013-01-01

Background Non-linear, parabolic (sub-exponential) and hyperbolic (super-exponential) models of prebiological evolution of molecular replicators have been proposed and extensively studied. The parabolic models appear to be the most realistic approximations of real-life replicator systems due primarily to product inhibition. Unlike the more traditional exponential models, the distribution of individual frequencies in an evolving parabolic population is not described by the Maximum Entropy (MaxEnt) Principle in its traditional form, whereby the distribution with the maximum Shannon entropy is chosen among all the distributions that are possible under the given constraints. We sought to identify a more general form of the MaxEnt principle that would be applicable to parabolic growth. Results We consider a model of a population that reproduces according to the parabolic growth law and show that the frequencies of individuals in the population minimize the Tsallis relative entropy (non-additive information gain) at each time moment. Next, we consider a model of a parabolically growing population that maintains a constant total size and provide an “implicit” solution for this system. We show that in this case, the frequencies of the individuals in the population also minimize the Tsallis information gain at each moment of the ‘internal time” of the population. Conclusions The results of this analysis show that the general MaxEnt principle is the underlying law for the evolution of a broad class of replicator systems including not only exponential but also parabolic and hyperbolic systems. The choice of the appropriate entropy (information) function depends on the growth dynamics of a particular class of systems. The Tsallis entropy is non-additive for independent subsystems, i.e. the information on the subsystems is insufficient to describe the system as a whole. In the context of prebiotic evolution, this “non-reductionist” nature of parabolic replicator systems might reflect the importance of group selection and competition between ensembles of cooperating replicators. Reviewers This article was reviewed by Viswanadham Sridhara (nominated by Claus Wilke), Puushottam Dixit (nominated by Sergei Maslov), and Nick Grishin. For the complete reviews, see the Reviewers’ Reports section. PMID:23937956

Data-Driven Modeling of Complex Systems by means of a Dynamical ANN

NASA Astrophysics Data System (ADS)

Seleznev, A.; Mukhin, D.; Gavrilov, A.; Loskutov, E.; Feigin, A.

2017-12-01

The data-driven methods for modeling and prognosis of complex dynamical systems become more and more popular in various fields due to growth of high-resolution data. We distinguish the two basic steps in such an approach: (i) determining the phase subspace of the system, or embedding, from available time series and (ii) constructing an evolution operator acting in this reduced subspace. In this work we suggest a novel approach combining these two steps by means of construction of an artificial neural network (ANN) with special topology. The proposed ANN-based model, on the one hand, projects the data onto a low-dimensional manifold, and, on the other hand, models a dynamical system on this manifold. Actually, this is a recurrent multilayer ANN which has internal dynamics and capable of generating time series. Very important point of the proposed methodology is the optimization of the model allowing us to avoid overfitting: we use Bayesian criterion to optimize the ANN structure and estimate both the degree of evolution operator nonlinearity and the complexity of nonlinear manifold which the data are projected on. The proposed modeling technique will be applied to the analysis of high-dimensional dynamical systems: Lorenz'96 model of atmospheric turbulence, producing high-dimensional space-time chaos, and quasi-geostrophic three-layer model of the Earth's atmosphere with the natural orography, describing the dynamics of synoptical vortexes as well as mesoscale blocking systems. The possibility of application of the proposed methodology to analyze real measured data is also discussed. The study was supported by the Russian Science Foundation (grant #16-12-10198).

INCOSE Systems Engineering Handbook v3.2: Improving the Process for SE Practitioners

DOE Office of Scientific and Technical Information (OSTI.GOV)

R. Douglas Hamelin; David D. Walden; Michael E. Krueger

2010-07-01

The INCOSE Systems Engineering Handbook is the official INCOSE reference document for understanding systems engineering (SE) methods and conducting SE activities. Over the years, the Handbook has evolved to accommodate advances in the SE discipline and now serves as the basis for the Certified Systems Engineering Professional (CSEP) exam. Due to its evolution, the Handbook had become somewhat disjointed in its treatment and presentation of SE topics and was not aligned with the latest version of International Organization for Standardization (ISO)/International Electrotechnical Commission (IEC) 15288:2008, Systems and Software Engineering. As a result, numerous inconsistencies were identified that could confuse practitionersmore » and directly impact the probability of success in passing the CSEP exam. Further, INCOSE leadership had previously submitted v3.1 of the Handbook to ISO/IEC for consideration as a Technical Report, but was told that the Handbook would have to be updated to conform with the terminology and structure of new ISO/IEC15288:2008, Systems and software engineering, prior to being considered. The revised INCOSE Systems Engineering Handbook v3.2 aligns with the structure and principles of ISO/IEC 15288:2008 and presents the generic SE life-cycle process steps in their entirety, without duplication or redundancy, in a single location within the text. As such, the revised Handbook v3.2 serves as a comprehensive instructional and reference manual for effectively understanding SE processes and conducting SE and better serves certification candidates preparing for the CSEP exam.« less

Globalizing Lessons Learned from Regional-scale Observatories

NASA Astrophysics Data System (ADS)

Glenn, S. M.

2016-02-01

The Mid Atlantic Regional Association Coastal Ocean Observing System (MARACOOS) has accumulated a decade of experience designing, building and operating a Regional Coastal Ocean Observing System for the U.S. Integrated Ocean Observing System (IOOS). MARACOOS serves societal goals and supports scientific discovery at the scale of a Large Marine Ecosystem (LME). Societal themes include maritime safety, ecosystem decision support, coastal inundation, water quality and offshore energy. Scientific results that feed back on societal goals with better products include improved understanding of seasonal transport pathways and their impact on phytoplankton blooms and hypoxia, seasonal evolution of the subsurface Mid Atlantic Cold Pool and its impact on fisheries, biogeochemical transformations in coastal plumes, coastal ocean evolution and impact on hurricane intensities, and storm sediment transport pathways. As the global ocean observing requirements grow to support additional societal needs for information on fisheries and aquaculture, ocean acidification and deoxygenation, water quality and offshore development, global observing will necessarily evolve to include more coastal observations and forecast models at the scale of the world's many LMEs. Here we describe our efforts to share lessons learned between the observatory operators at the regional-scale of the LMEs. Current collaborators are spread across Europe, and also include Korea, Indonesia, Australia, Brazil and South Africa. Specific examples include the development of a world standard QA/QC approach for HF Radar data that will foster the sharing of data between countries, basin-scale underwater glider missions between internationally-distributed glider ports to developed a shared understanding of operations and an ongoing evaluation of the global ocean models in which the regional models for the LME will be nested, and joint training programs to develop the distributed teams of scientists and technicians required to support the global network. Globalization includes the development of international networks to coordinate activities, such as the Global HF Radar network supported by GEO, the global Everyone's Glider Organization supported by WMO and IOC, and the need for professional training supported by MTS.

The International Journal of Astrobiology

NASA Astrophysics Data System (ADS)

Wynn-Williams, David D.

2002-01-01

The launch of a new journal is appropriately like a space mission. It is the result of a scientific need, the inspiration of a group of committed scientists and technologists, a series of draft proposals, an approved mission protocol, and a launch. Today is the launch day for a journal whose remit has only recently consolidated from diverse disciplines. Cambridge University Press has an international reputation for astronomy. To this we add extreme biology and its associated environmental research to integrate astrobiology as: 'the study of the origin, evolution, adaptation and distribution of past and present life in the Universe'. Astrobiology has three main themes: (1) Origin, evolution and limits of life on Earth; (2) Future of life, both on Earth and elsewhere; (3) Search for habitats, biomolecules and life in the Solar System and elsewhere. These fundamental concepts require the integration of various disciplines, including biology (especially microbiology), chemistry, geology, palaeontology, and the physics of atmospheres, planets and stars. We must also keep our minds wide open about the nature and limits of life. We can safely assume a carbon-based system within Solar Systems as we know them, but our concept of habitable zones expands yearly. We were taught that only the spores of certain bacilli could survive temperatures above the boiling point of water, and yet we now know that the deep-sea vent microbe Pyrolobus can survive an hour at 121 °C, which is the temperature used for sterilising medical instruments. We know of cyanobacteria which can not only live inside deep-frozen Antarctic rocks but also survive on roof-tops in Jerusalem at 80 °C. The bacterium Deinococcus radiodurans tolerates lethal doses of nuclear radiation, and cyanobacteria inside Antarctic desert sandstone receive so little moisture that their carbon turnover time (from its fixation by photosynthesis to its release as carbon dioxide during respiration) is 10,000 years. Life is tolerant, adaptable and tenacious.

AMMA-CATCH a Hydrological, Meteorological and Ecological Long Term Observatory on West Africa : Some Recent Results

NASA Astrophysics Data System (ADS)

Galle, S.; Grippa, M.; Peugeot, C.; Bouzou Moussa, I.; Cappelaere, B.; Demarty, J.; Mougin, E.; Lebel, T.; Chaffard, V.

2015-12-01

AMMA-CATCH is a multi-scale observation system dedicated to long-term monitoring of the water cycle, the vegetation dynamics and their interaction with climate and water resources in West Africa. In the context of the global change, long-term observations are required to i) gain understanding in eco-hydrological processes over this highly contrasted region, ii) help their representation in Earth System Models, and iii) detect trends and infer their impacts on water resources and living conditions. It is made of three meso-scale sites (~ 1°x1°) in Mali, Niger and Benin, extending along the West African eco-climatic gradient. Within this regional window (5° by 9°), each of the three sites comprises a multi-scale set-up which helps documenting the components of the hydrologic budget and the evolutions of the surface conditions over a range of time scales: raingages, piezometers, river discharge stations, soil moisture and temperature profiles, turbulent fluxes measurements, LAI/biomass monitoring. This observation system has been continuously generating coherent datasets for 10 to 25 years depending on the datasets. It is jointly operated by French and African (Mali, Niger and Benin) research institutions. The data-base is available to the community through the website (www.amma-catch.org). AMMA-CATCH is a member of the French critical zone observatory network "Réseau des Bassins Versants", (RBV). AMMA-CATH participates to several global or regional observation networks, such as FluxNet, CarboAfrica, International Soil Moisture Networks (ISMN) and to calibration/validation campaigns for satellite missions such as SMOS (CNES, ESA), MEGHA-TROPIQUES (France/India) or SWAP(NASA). AMMA-CATCH fills a gap over a region, West Africa, where environmental data are largely lacking, and thus, it can usefully contribute to the international networking effort for environmental monitoring and research. Recent results on regional evolution of land cover, rainfall intensity and their consequences on eco-hydrological processes and hydrosystems will be presented.

An evolution strategy for lunar nuclear surface power

NASA Technical Reports Server (NTRS)

Mason, Lee S.

1992-01-01

The production and transmission of electric power for a permanently inhabited lunar base poses a significant challenge which can best be met through an evolution strategy. Nuclear systems offer the best opportunity for evolution in terms of both life and performance. Applicable nuclear power technology options include isotope systems (either radioisotope thermoelectric generators or dynamic isotope power systems) and reactor systems with either static (thermoelectric or thermionic) or dynamic (Brayton, Stirling, Rankine) conversion. A power system integration approach that takes evolution into account would benefit by reduced development and operations cost, progressive flight experience, and simplified logistics, and would permit unrestrained base expansion. For the purposes of defining a nuclear power system evolution strategy, the lunar base development shall consist of four phases: precursor, emplacement, consolidation, and operations.

Strategic Options for International Participation in Space Exploration: Lessons from U.S.-Japan Defense Cooperation

NASA Technical Reports Server (NTRS)

Hudiburg, John J.; Chinworth, Michael W.

2005-01-01

The President's Commission on Implementation of United States Space Exploration Policy suggests that after NASA establishes the Space Exploration vision architecture, it should pursue international partnerships. Two possible approaches were suggested: multiple independently operated missions and an integrated mission with carefully selected international components. The U.S.-Japan defense sectors have learned key lessons from experience with both of these approaches. U.S.-Japan defense cooperation has evolved over forty years from simple military assistance programs to more complex joint development efforts. With the evolution of the political-military alliance and the complexity of defense programs, these cooperative efforts have engaged increasingly industrial resources and capabilities as well as more sophisticated forms of planning, technology transfers and program management. Some periods of this evolution have been marked by significant frictions. The U.S.Japan FS-X program, for example, provides a poor example for management of international cooperation. In November 1988, the United States and Japan signed a Memorandum of Understanding (MOU) to co-develop an aircraft, named FS-X and later renamed F -2, as a replacement to the aging Japan support fighter F-l. The program was marked by numerous political disputes. After over a decade of joint development and testing, F -2 production deliveries finally began in 1999. The production run was curtailed due to much higher than anticipated costs and less than desired aircraft performance. One universally agreed "lesson" from the FSX/F-2 case was that it did not represent the ideal approach to bilateral cooperation. More recent cooperative programs have involved targeted joint research and development, including component development for ballistic missile defense systems. These programs could lay the basis for more ambitious cooperative efforts. This study examines both less-than-stellar international cooperation efforts as well as more successful initiatives to identify lessons from military programs that can help NASA encourage global investment in its Space Exploration Vision. The paper establishes a basis for examining related policy and industrial concerns such as effective utilization of dual-use technologies and trans-Pacific program management of large, complex cooperative programs.

Brain reorganization, not relative brain size, primarily characterizes anthropoid brain evolution.

PubMed

Smaers, J B; Soligo, C

2013-05-22

Comparative analyses of primate brain evolution have highlighted changes in size and internal organization as key factors underlying species diversity. It remains, however, unclear (i) how much variation in mosaic brain reorganization versus variation in relative brain size contributes to explaining the structural neural diversity observed across species, (ii) which mosaic changes contribute most to explaining diversity, and (iii) what the temporal origin, rates and processes are that underlie evolutionary shifts in mosaic reorganization for individual branches of the primate tree of life. We address these questions by combining novel comparative methods that allow assessing the temporal origin, rate and process of evolutionary changes on individual branches of the tree of life, with newly available data on volumes of key brain structures (prefrontal cortex, frontal motor areas and cerebrocerebellum) for a sample of 17 species (including humans). We identify patterns of mosaic change in brain evolution that mirror brain systems previously identified by electrophysiological and anatomical tract-tracing studies in non-human primates and functional connectivity MRI studies in humans. Across more than 40 Myr of anthropoid primate evolution, mosaic changes contribute more to explaining neural diversity than changes in relative brain size, and different mosaic patterns are differentially selected for when brains increase or decrease in size. We identify lineage-specific evolutionary specializations for all branches of the tree of life covered by our sample and demonstrate deep evolutionary roots for mosaic patterns associated with motor control and learning.

Brain reorganization, not relative brain size, primarily characterizes anthropoid brain evolution

PubMed Central

Smaers, J. B.; Soligo, C.

2013-01-01

Comparative analyses of primate brain evolution have highlighted changes in size and internal organization as key factors underlying species diversity. It remains, however, unclear (i) how much variation in mosaic brain reorganization versus variation in relative brain size contributes to explaining the structural neural diversity observed across species, (ii) which mosaic changes contribute most to explaining diversity, and (iii) what the temporal origin, rates and processes are that underlie evolutionary shifts in mosaic reorganization for individual branches of the primate tree of life. We address these questions by combining novel comparative methods that allow assessing the temporal origin, rate and process of evolutionary changes on individual branches of the tree of life, with newly available data on volumes of key brain structures (prefrontal cortex, frontal motor areas and cerebrocerebellum) for a sample of 17 species (including humans). We identify patterns of mosaic change in brain evolution that mirror brain systems previously identified by electrophysiological and anatomical tract-tracing studies in non-human primates and functional connectivity MRI studies in humans. Across more than 40 Myr of anthropoid primate evolution, mosaic changes contribute more to explaining neural diversity than changes in relative brain size, and different mosaic patterns are differentially selected for when brains increase or decrease in size. We identify lineage-specific evolutionary specializations for all branches of the tree of life covered by our sample and demonstrate deep evolutionary roots for mosaic patterns associated with motor control and learning. PMID:23536600

Methods and Systems for Measurement and Estimation of Normalized Contrast in Infrared Thermography

NASA Technical Reports Server (NTRS)

Koshti, Ajay M. (Inventor)

2017-01-01

Methods and systems for converting an image contrast evolution of an object to a temperature contrast evolution and vice versa are disclosed, including methods for assessing an emissivity of the object; calculating an afterglow heat flux evolution; calculating a measurement region of interest temperature change; calculating a reference region of interest temperature change; calculating a reflection temperature change; calculating the image contrast evolution or the temperature contrast evolution; and converting the image contrast evolution to the temperature contrast evolution or vice versa, respectively.

Methods and Systems for Measurement and Estimation of Normalized Contrast in Infrared Thermography

NASA Technical Reports Server (NTRS)

Koshti, Ajay M. (Inventor)

2015-01-01

Methods and systems for converting an image contrast evolution of an object to a temperature contrast evolution and vice versa are disclosed, including methods for assessing an emissivity of the object; calculating an afterglow heat flux evolution; calculating a measurement region of interest temperature change; calculating a reference region of interest temperature change; calculating a reflection temperature change; calculating the image contrast evolution or the temperature contrast evolution; and converting the image contrast evolution to the temperature contrast evolution or vice versa, respectively.

Damage evolution during actuation fatigue in shape memory alloys (SPIE Best Student Paper Award)

NASA Astrophysics Data System (ADS)

Phillips, Francis R.; Wheeler, Robert; Lagoudas, Dimitris C.

2018-03-01

Shape Memory Alloys (SMAs) are unique materials able to undergo a thermomechanically induced, reversible phase transformation. Additionally, SMA are subject to two types of fatigue, that is structural fatigue due to cyclic loading as experienced by most materials, as well as actuation fatigue due to repeated thermally induced phase transformation. The evolution of multiple material characteristics is presented over the actuation fatigue lifetime of NiTiHf actuators, including the accumulation of irrecoverable strain, the evolution of internal voids, and the evolution of the effective modulus of the actuator. The results indicate that all three of these material characteristics are clearly interconnected and careful analysis of each of these characteristics can help to understand the evolution of the others, as well as help to understand how actuation fatigue leads to ultimate failure of the actuator.

CADC and CANFAR: Extending the role of the data centre

NASA Astrophysics Data System (ADS)

Gaudet, Severin

2015-12-01

Over the past six years, the CADC has moved beyond the astronomy archive data centre to a multi-service system for the community. This evolution is based on two major initiatives. The first is the adoption of International Virtual Observatory Alliance (IVOA) standards in both the system and data architecture of the CADC, including a common characterization data model. The second is the Canadian Advanced Network for Astronomical Research (CANFAR), a digital infrastructure combining the Canadian national research network (CANARIE), cloud processing and storage resources (Compute Canada) and a data centre (Canadian Astronomy Data Centre) into a unified ecosystem for storage and processing for the astronomy community. This talk will describe the architecture and integration of IVOA and CANFAR services into CADC operations, the operational experiences, the lessons learned and future directions

ISS ECLSS Technology Evolution for Exploration

NASA Technical Reports Server (NTRS)

Carrasquillo, Robyn L.

2005-01-01

The baseline environmental control and life support systems (ECLSS) currently deployed on the International Space Station (ISS) and the regenerative oxygen generation and water reclamation systems to be added in 2008 are based on technologies selected during the early 1990's. While they are generally meeting, or exceeding requirements for supporting the ISS crew, lessons learned from hardware development and on orbit experience, together with advances in technology state of the art, and the unique requirements for future manned exploration missions prompt consideration of the next steps to be taken to evolve these technologies to improve robustness and reliability, enhance performance, and reduce resource requirements such as power and logistics upmass. This paper discusses the current state of ISS ECLSS technology and identifies possible areas for evolutionary enhancement or improvement.

Sandbox rheometry: Co-evolution of stress and strain in Riedel- and Critical Wedge-experiments

NASA Astrophysics Data System (ADS)

Ritter, Malte C.; Santimano, Tasca; Rosenau, Matthias; Leever, Karen; Oncken, Onno

2018-01-01

Analogue sandbox experiments have been used for a long time to understand tectonic processes, because they facilitate detailed measurements of deformation at a spatio-temporal resolution unachievable from natural data. Despite this long history, force measurements to further characterise the mechanical evolution in analogue sandbox experiments have only emerged recently. Combined continuous measurements of forces and deformation in such experiments, an approach here referred to as "sandbox rheometry", are a new tool that may help to better understand work budgets and force balances for tectonic systems and to derive constitutive laws for regional scale deformation. In this article we present an experimental device that facilitates precise measurements of boundary forces and surface deformation at high temporal and spatial resolution. We demonstrate its capabilities in two classical experiments: one of strike-slip deformation (the Riedel set-up) and one of compressional accretionary deformation (the Critical Wedge set-up). In these we are able to directly observe a correlation between strain weakening and strain localisation that had previously only been inferred, namely the coincidence of the maximum localisation rate with the onset of weakening. Additionally, we observe in the compressional experiment a hysteresis of localisation with respect to the mechanical evolution that reflects the internal structural complexity of an accretionary wedge.

Ecological transition predictably associated with gene degeneration.

PubMed

Wessinger, Carolyn A; Rausher, Mark D

2015-02-01

Gene degeneration or loss can significantly contribute to phenotypic diversification, but may generate genetic constraints on future evolutionary trajectories, potentially restricting phenotypic reversal. Such constraints may manifest as directional evolutionary trends when parallel phenotypic shifts consistently involve gene degeneration or loss. Here, we demonstrate that widespread parallel evolution in Penstemon from blue to red flowers predictably involves the functional inactivation and degeneration of the enzyme flavonoid 3',5'-hydroxylase (F3'5'H), an anthocyanin pathway enzyme required for the production of blue floral pigments. Other types of genetic mutations do not consistently accompany this phenotypic shift. This pattern may be driven by the relatively large mutational target size of degenerative mutations to this locus and the apparent lack of associated pleiotropic effects. The consistent degeneration of F3'5'H may provide a mechanistic explanation for the observed asymmetry in the direction of flower color evolution in Penstemon: Blue to red transitions are common, but reverse transitions have not been observed. Although phenotypic shifts in this system are likely driven by natural selection, internal constraints may generate predictable genetic outcomes and may restrict future evolutionary trajectories. © The Author 2014. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Epidemiology, Evolution, and Pathogenesis of H7N9 Influenza Viruses in Five Epidemic Waves since 2013 in China.

PubMed

Su, Shuo; Gu, Min; Liu, Di; Cui, Jie; Gao, George F; Zhou, Jiyong; Liu, Xiufan

2017-09-01

H7N9 influenza viruses were first isolated in 2013 and continue to cause human infections. H7N9 infections represent an ongoing public health threat that has resulted in 1344 cases with 511 deaths as of April 9, 2017. This highlights the continued threat posed by the current poultry trade and live poultry market system in China. Until now, there have been five H7N9 influenza epidemic waves in China; however, the steep increase in the number of humans infected with H7N9 viruses observed in the fifth wave, beginning in October 2016, the spread into western provinces, and the emergence of highly pathogenic (HP) H7N9 influenza outbreaks in chickens and infection in humans have caused domestic and international concern. In this review, we summarize and compare the different waves of H7N9 regarding their epidemiology, pathogenesis, evolution, and characteristic features, and speculate on factors behind the recent increase in the number of human cases and sudden outbreaks in chickens. The continuous evolution of the virus poses a long-term threat to public health and the poultry industry, and thus it is imperative to strengthen prevention and control strategies. Copyright © 2017. Published by Elsevier Ltd.

Diversity of the luciferin binding protein gene in bioluminescent dinoflagellates--insights from a new gene in Noctiluca scintillans and sequences from gonyaulacoid genera.

PubMed

Valiadi, Martha; Iglesias-Rodriguez, Maria Debora

2014-01-01

Dinoflagellate bioluminescence systems operate with or without a luciferin binding protein, representing two distinct modes of light production. However, the distribution, diversity, and evolution of the luciferin binding protein gene within bioluminescent dinoflagellates are not well known. We used PCR to detect and partially sequence this gene from the heterotrophic dinoflagellate Noctiluca scintillans and a group of ecologically important gonyaulacoid species. We report an additional luciferin binding protein gene in N. scintillans which is not attached to luciferase, further to its typical combined bioluminescence gene. This supports the hypothesis that a profound re-organization of the bioluminescence system has taken place in this organism. We also show that the luciferin binding protein gene is present in the genera Ceratocorys, Gonyaulax, and Protoceratium, and is prevalent in bioluminescent species of Alexandrium. Therefore, this gene is an integral component of the standard molecular bioluminescence machinery in dinoflagellates. Nucleotide sequences showed high within-strain variation among gene copies, revealing a highly diverse gene family comprising multiple gene types in some organisms. Phylogenetic analyses showed that, in some species, the evolution of the luciferin binding protein gene was different from the organism's general phylogenies, highlighting the complex evolutionary history of dinoflagellate bioluminescence systems. © 2013 The Author(s) Journal of Eukaryotic Microbiology © 2013 International Society of Protistologists.

The Evolution of Academic Performance in Nine Subspecialties of Internal Medicine: An Analysis of Journal Citation Reports from 1998 to 2010

PubMed Central

Zhang, Xue-Guang; Zhang, Li; Liu, Shu-Wen; Cao, Xue-Ying; Wang, Yuan-Da; Wei, Ri-Bao; Cai, Guang-Yan; Chen, Xiang-Mei

2012-01-01

Background Internal medicine includes several subspecialties. This study aimed to describe change trend of impact factors in different subspecialties of internal medicine during the past 12 years, as well as the developmental differences among each subspecialty, and the possible influencing factors behind these changes and differences. Methods Nine subspecialties of internal medicine were chosen for comparison. All data were collected from the Science Citation Index Expanded and Journal Citation Reports database. Results (1) Journal numbers in nine subspecialties increased significantly from 1998 to 2010, with an average increment of 80.23%, in which cardiac and cardiovascular system diseases increased 131.2% rank the first; hematology increased 45% rank the least. (2) Impact Factor in subspecialties of infectious disease, cardiac and cardiovascular system diseases, gastroenterology and hepatology, hematology, endocrinology and metabolism increased significantly (p<0.05), in which gastroenterology and hepatology had the largest increase of 65.4%. (3) Journal impact factor of 0–2 had the largest proportion in all subspecialties. Among the journals with high impact factor (IF>6), hematology had the maximum proportion of 10%, nephrology and respiratory system disease had the minimum of 4%. Among the journal with low impact factor (IF<2), journal in nephrology and allergy had the most (60%), while endocrinology and metabolism had the least (40%). There were differences in median number of IF among the different subspecialties (p<0.05), in which endocrinology and metabolism had the highest, nephrology had the lowest. (4) The highest IF had a correlation with journal numbers and total paper numbers in each field. Conclusion The IF of internal medicine journals showed an increasingly positive trend, in which gastroenterology and hepatology increase the most. Hematology had more high IF journals. Endocrinology and metabolism had higher average IF. Nephrology remained the lowest position. Numbers of journals and total papers were associated with the highest IF. PMID:23118973

Spontaneous ovarian hyper stimulation syndrome and deep vein thrombosis in a non pregnant woman: case report.

PubMed

Attia, Leila; Azzabi, Samira; Ben Hassine, Lamia; Chachia, Abdelatif; Koubâa, Abdelhamid; Khalfallah, Narjes

2007-12-01

To assess aetiological factors and complications in a patient with severe ovarian hyperstimulation syndrome (OHSS) and internal jugular vein thrombosis. A 27-year-old non pregnant woman with bilateral ovarian masses who had underwent laparotomy for suspicion of malignant tumor. The pathological examination disclosed malignancy and the diagnosis of OHSS were confirmed. The postoperative evolution was complicated by internal jugular, subclavian vein thrombosis and pulmonary embolism. All biological parameters were negative. The evolution was good. The incidence of thromboembolism in women with OHSS is low and the typical finding is deep venous thrombosis in the neck area. Preventive measure of OHSS is very important, and the patients must be treated timely and correctly once OHSS occurs.

The Grand Challenges of WCRP and the Climate Observing System of the Future

NASA Astrophysics Data System (ADS)

Brasseur, G. P.

2017-12-01

The successful implementation the Paris agreement on climate change (COP21) calls for a well-designed global monitoring system of essential climate variables, climate processes and Earth system budgets. The Grand Challenges implemented by the World Climate Research Programme (WCRP) provide an opportunity to investigate issues of high societal relevance, directly related to sea level rise, droughts, floods, extreme heat events, food security, and fresh water availability. These challenges would directly benefit from a well-designed suite of systematic climate observations. Quantification of the evolution of the global energy, water and carbon budgets as well as the development and the production of near-term and regional climate predictions require that a comprehensive, focused, multi-platform observing system (satellites, ground-based and in situ observations) be established in an international context. This system must be accompanied by the development of climate services that should translate and disseminate scientific outcomes as actionable information for users and stakeholders.

Marine data management: a positive evolution from JGOFS to OCEANS

NASA Astrophysics Data System (ADS)

Avril, B.

2003-04-01

The JGOFS project has been highly successful in providing new insights into global biogeochemical cycling of carbon and associated elements in the oceans through a multi-national effort at the regional scale (process studies in the North Atlantic, Arabian Sea, Equatorial Pacific, Southern Ocean and North Pacific), global scale (carbon survey) and from long-term measurements at key ocean sites (time-series). The database thus created is very large and complex in diversity and format, and it is currently managed at the international level, thank to the efforts of the JGOFS Data Management Task Team. To be fully usable for current and future studies, the JGOFS datasets will be organised as a single database (so-called, the International JGOFS Master Dataset), in a single format and in a single location (in the World Data Centre (WDC) system, thanks to an initiative of PANGAEA / WDC-MARE; and on CDs or DVDs) before the end of the project (Dec. 2003). This should be achieved by adapting previously developed tools, especially from the US-JGOFS DMO (for the user query interface) and from ODV/PANGAEA (for the datasets visualization and metadata handling). Whilst the OCEANS project science and implementation plans are being prepared, the international oceanographic community is now hoping to benefit from the JGOFS data management experience and to elaborate beforehand the best design and practices for its data management. The draft OCEANS data management plan (international data policy and recommendations for participating international agencies and national data managers) is presented. This plan should result in the rapid and full availability of data, and its long-term preservation and accessibility, thanks to a better, integrated and fully implemented data management system.

The Evolution of International Business Textbooks

ERIC Educational Resources Information Center

Sagafi-nejad, Tagi; Limaye, Aditya

2014-01-01

As a field of study, international business (IB) has evolved with accelerated tempo in the last four decades. The subject has brought with it an increasing plethora of textbooks. We analyze the contents of major textbooks, both classic and new, to find the extent to which these textbooks cover the various components of the common body of knowledge…

Developing International Competitiveness on a Broad Front: Country Needs and a College Response.

ERIC Educational Resources Information Center

Clayton, Graham

This two-part report explains the economic importance of international trade to the Canadian economy and reviews responses taken by Ontario's Confederation College to the threats and opportunities posed by economic globalization. The first part traces Canada's economic evolution over the past 50 years; summarizes post-World War II global economic…

A Highly-Regulated "Free Market": Commonwealth Policies on Private Overseas Students from 1974 to 2005

ERIC Educational Resources Information Center

Megarrity, Lyndon

2007-01-01

This article traces the evolution of Commonwealth policies on private overseas students from the 1970s to the present, emphasising the Commonwealth government's role in the creation of an international education market. It will be argued that while neoliberal "market forces" rhetoric has been a key feature of its international education…

Proceedings of the International Round Table on Vocational Training and Employment (Turin, Italy, June 17-20, 1991).

ERIC Educational Resources Information Center

Istituto per lo Sviluppo della Formazione Professionale dei Lavoratori, Rome (Italy).

Eleven papers are presented from the International Round Table on Vocational Training and Employment. Introductory materials are the program and list of participants. The papers are as follows: "Evolution de la Formation Professionnelle en Afrique et Contribution du Ciadfor au Cours de la Derniere Decennie" (in French); "Educacion,…

Greening the Grid: Solar and Wind Grid Integration Study for the Luzon-Visayas System of the Philippines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barrows, Clayton P.; Katz, Jessica R.; Cochran, Jaquelin M.

The Republic of the Philippines is home to abundant solar, wind, and other renewable energy (RE) resources that contribute to the national government's vision to ensure sustainable, secure, sufficient, accessible, and affordable energy. Because solar and wind resources are variable and uncertain, significant generation from these resources necessitates an evolution in power system planning and operation. To support Philippine power sector planners in evaluating the impacts and opportunities associated with achieving high levels of variable RE penetration, the Department of Energy of the Philippines (DOE) and the United States Agency for International Development (USAID) have spearheaded this study along withmore » a group of modeling representatives from across the Philippine electricity industry, which seeks to characterize the operational impacts of reaching high solar and wind targets in the Philippine power system, with a specific focus on the integrated Luzon-Visayas grids.« less

Molecular oscillation behind the clockface.

PubMed

Fukada, Yoshitaka

2003-12-01

The earth rotates on its own axis while orbiting around the sun. This regular movement of the solar system results in cyclic changes of the light condition of the earth with a period of 24 h, although the lengths of daytime and nighttime depend on the latitude. The organisms living on the earth have evolved an internal time-measuring system called the "circadian clock," which ticks with a period of approximately 24 h in order to adapt to the environment and to anticipate the next cycle. The fact that most of existing organisms retain the circadian clock suggests that the clock-ownership must have been advantageous over non-ownership during their evolution. Here I will introduce the background of the research field of circadian rhythm and present an outline of this Special Review series, which is composed of three articles that review recent research into the molecular mechanisms of the three types of circadian clock systems in vertebrates.

Development and Deployment of the Extended Reach Sluicing System (ERSS) for Retrieval of Hanford Single Shell Tank Waste. Draft

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bauer, Roger E.; Figley, Reed R.; Innes, A. G.

2013-11-11

A history of the evolution and the design development of Extended Reach Sluicer System (ERSS) is presented. Several challenges are described that had to be overcome to create a machine that went beyond the capabilities of prior generation sluicers to mobilize waste in Single Shell Tanks for pumping into Double Shell Tank receiver tanks. Off-the-shelf technology and traditional hydraulic fluid power systems were combined with the custom-engineered components to create the additional functionality of the ERSS, while still enabling it to fit within very tight entry envelope into the SST. Problems and challenges inevitably were encountered and overcome in waysmore » that enhance the state of the art of fluid power applications in such constrained environments. Future enhancements to the ERSS design are explored for retrieval of tanks with different dimensions and internal obstacles.« less

The core mass-radius relation for giants - A new test of stellar evolution theory

NASA Technical Reports Server (NTRS)

Joss, P. C.; Rappaport, S.; Lewis, W.

1987-01-01

It is demonstrated here that the measurable properties of systems containing degenerate dwarfs can be used as a direct test of the core mass-radius relation for moderate-mass giants if the final stages of the loss of the envelope of the progenitor giant occurred via stable critical lobe overflow. This relation directly probes the internal structure of stars at a relatively advanced evolutionary state and is only modestly influenced by adjustable parameters. The measured properties of six binary systems, including such diverse systems as Sirius and Procyon and two millisecond pulsars, are utilized to derive constraints on the empirical core mass-radius relation, and the constraints are compared to the theoretical relation. The possibility that the final stages of envelope ejection of the giant progenitor of Sirius B occurred via critical lobe overflow in historical times is considered.

Early evolution of the earth - Accretion, atmosphere formation, and thermal history

NASA Technical Reports Server (NTRS)

Abe, Yutaka; Matsui, Takafumi

1986-01-01

The thermal and atmospheric evolution of the earth growing planetesimal impacts are studied. The generation of an H2O protoatmosphere is examined, and the surface temperatures are estimated. The evolution of an impact-induced H2O atmosphere is analyzed. Consideration is given to the formation time of a 'magma ocean'and internal water budgets. The thermal history of an accreting earth is reviewed. The wet convection and greenhouse effects are discussed, and the role of Fe oxidation on the evolution of an impact-induced H2O atmopshere is described. The relationship between differentiation processes and core segregation, the H2O and FeO content of the mantle, and the origin of the hydrosphere is also examined.

Terra Mission Operations: Launch to the Present (and Beyond)

NASA Technical Reports Server (NTRS)

Thome, Kurt; Kelly, Angelita; Moyer, Eric; Mantziaras, Dimitrios; Case, Warren

2014-01-01

The Terra satellite, flagship of NASAs long-term Earth Observing System (EOS) Program, continues to provide useful earth science observations well past its 5-year design lifetime. This paper describes the evolution of Terra operations, including challenges and successes and the steps taken to preserve science requirements and prolong spacecraft life. Working cooperatively with the Terra science and instrument teams, including NASAs international partners, the mission operations team has successfully kept the Terra operating continuously, resolving challenges and adjusting operations as needed. Terra retains all of its observing capabilities (except Short Wave Infrared) despite its age. The paper also describes concepts for future operations.

Modeling Common-Sense Decisions

NASA Astrophysics Data System (ADS)

Zak, Michail

This paper presents a methodology for efficient synthesis of dynamical model simulating a common-sense decision making process. The approach is based upon the extension of the physics' First Principles that includes behavior of living systems. The new architecture consists of motor dynamics simulating actual behavior of the object, and mental dynamics representing evolution of the corresponding knowledge-base and incorporating it in the form of information flows into the motor dynamics. The autonomy of the decision making process is achieved by a feedback from mental to motor dynamics. This feedback replaces unavailable external information by an internal knowledgebase stored in the mental model in the form of probability distributions.

Small-Scale Tropopause Dynamics and TOMS Total Ozone

NASA Technical Reports Server (NTRS)

Stanford, John L.

2002-01-01

This project used Earth Probe Total Ozone Mapping Spectrometer (EP TOMS) along-track ozone retrievals, in conjunction with ancillary meteorological fields and modeling studies, for high resolution investigations of upper troposphere and lower stratosphere dynamics. Specifically, high resolution along-track (Level 2) EP TOMS data were used to investigate the beautiful fine-scale structure in constituent and meteorological fields prominent in the evolution of highly non-linear baroclinic storm systems. Comparison was made with high resolution meteorological models. The analyses provide internal consistency checks and validation of the EP TOMS data which are vital for monitoring ozone depletion in both polar and midlatitude regions.

Testing palaeotectonic models for the Internal Hellenides with sediment provenance

NASA Astrophysics Data System (ADS)

Meinhold, G.

2009-04-01

The Internal Hellenides of Greece are a result of the Alpine-Himalayan orogen. The relationships between different pre-Alpine crustal fragments of the Internal Hellenides are now masked by younger (Mesozoic to Cenozoic) complex structural and metamorphic events. This, together with the scarcity of biostratigraphic, geochronological and palaeomagnetic data, has given rise to equivocal palaeotectonic models and interpretations. However, the age and origin of pre-Alpine basement units in the Internal Hellenides has important implications for our in-depth understanding of the evolution of North Gondwana-derived terranes and consequently for alternative palaeotectonic reconstructions for the Palaeozoic and Mesozoic. A multidisciplinary sediment provenance study was undertaken since sedimentary rocks can provide information about rock lithologies in the source area, which have often been destroyed and recycled during ancient plate tectonic processes. Palaeozoic and Mesozoic sedimentary rocks from key areas of the Internal Hellenides were analysed using whole-rock major- and trace-element geochemistry (XRF, ICPMS), detrital chrome spinel, garnet, white mica and rutile chemistry (EMP), detrital zircon geochronology (SHRIMP, LA-ICPMS) and biostratigraphic analysis. These new data are used to constrain terrane accretion processes and the provenance of crustal sources for sediments during Palaeozoic and Mesozoic times and thus will test palaeotectonic models for the Internal Hellenides. This is expected to shed light on the Palaeo- and Neotethyan evolution in the Eastern Mediterranean.

In Situ Probe Science at Saturn

NASA Astrophysics Data System (ADS)

Atkinson, David H.; Lunine, Jonathan I.; Simon-Miller, Amy A.; Atreya, Sushil K.; Brinckerhoff, William B.; Colaprete, Anthony; Coustenis, Athena; Fletcher, Leigh N.; Guillot, Tristan; Lebreton, Jean-Pierre; Mahaffy, Paul; Mousis, Olivier; Orton, Glenn S.; Reh, Kim; Spilker, Linda J.; Spilker, Thomas R.; Webster, Chris R.

2014-05-01

A fundamental goal of solar system exploration is to understand the origin of the solar system, the initial stages, conditions, and processes by which the solar system formed, how the formation process was initiated, and the nature of the interstellar seed material from which the solar system was born. Key to understanding solar system formation and subsequent dynamical and chemical evolution is the origin and evolution of the giant planets and their atmospheres. Several theories have been put forward to explain the process of solar system formation, and the origin and evolution of the giant planets and their atmospheres. Each theory offers quantifiable predictions of the abundances of noble gases He, Ne, Ar, Kr, and Xe, and abundances of key isotopic ratios 4He/3He, D/H, 15N/14N, 18O/16O, and 13C/12C. Detection of certain disequilibrium species, diagnostic of deeper internal processes and dynamics of the atmosphere, would also help discriminate between competing theories. Many of the key atmospheric constituents needed to discriminate between alternative theories of giant planet formation and chemical evolution are either spectrally inactive or primarily located in the deeper atmosphere inaccessible to remote sensing from Earth, flyby, or orbiting spacecraft. Abundance measurements of these key constituents, including the two major molecular carriers of carbon, methane and carbon monoxide (neither of which condense in Saturn's atmosphere), sulfur which is expected to be well-mixed below the 4 to 5-bar ammonium hydrosulfide (NH4SH) cloud, and gradients of nitrogen below the NH4SH cloud and oxygen in the upper layers of the H2O and H2O-NH4 solution cloud, must be made in situ and can only be achieved by an entry probe descending through 10 bars. Measurements of the critical abundance profiles of these key constituents into the deeper well-mixed atmosphere must be complemented by measurements of the profiles of atmospheric structure and dynamics at high vertical resolution that also require in situ exploration. The atmospheres of the giant planets can also serve as laboratories to better understand the atmospheric chemistries, dynamics, processes, and climates on all planets in the solar system including Earth, and offer a context and provide a ground truth for exoplanets and exoplanetary systems. Additionally, Giant planets have long been thought to play a critical role in the development of potentially habitable planetary systems. In the context of giant planet science provided by the Galileo, Juno, and Cassini missions to Jupiter and Saturn, a small, relatively shallow Saturn probe capable of measuring abundances and isotopic ratios of key atmospheric constituents, and atmospheric structure including pressures, temperatures, dynamics, and cloud locations and properties not accessible by remote sensing can serve to test competing theories of solar system and giant planet origin, chemical, and dynamical evolution. Acknowledgements This research was carried out in part at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. Copyright 2013 California Institute of Technology. U.S. Government sponsorship acknowledged. O. Mousis acknowledges support from CNES.

Effect of Interface Structure on the Microstructural Evolution of Ceramics

DTIC Science & Technology

2007-11-06

because almost all the material properties are de - pendent upon their internal microstructures. Therefore, the microstructural evolution during the...growing interface de - pends upon the density of kinks on that interface. It fol- lows that the atomically smooth interface, which is char- acterized by...grain, and its de - tailed coarsening process has been treated elsewhere.139 During liquid-phase sintering, the formation of grain boundaries between

A large oxygen-dominated core from the seismic cartography of a pulsating white dwarf

NASA Astrophysics Data System (ADS)

Giammichele, N.; Charpinet, S.; Fontaine, G.; Brassard, P.; Green, E. M.; Van Grootel, V.; Bergeron, P.; Zong, W.; Dupret, M.-A.

2018-02-01

White-dwarf stars are the end product of stellar evolution for most stars in the Universe. Their interiors bear the imprint of fundamental mechanisms that occur during stellar evolution. Moreover, they are important chronometers for dating galactic stellar populations, and their mergers with other white dwarfs now appear to be responsible for producing the type Ia supernovae that are used as standard cosmological candles. However, the internal structure of white-dwarf stars—in particular their oxygen content and the stratification of their cores—is still poorly known, because of remaining uncertainties in the physics involved in stellar modelling codes. Here we report a measurement of the radial chemical stratification (of oxygen, carbon and helium) in the hydrogen-deficient white-dwarf star KIC08626021 (J192904.6+444708), independently of stellar-evolution calculations. We use archival data coupled with asteroseismic sounding techniques to determine the internal constitution of this star. We find that the oxygen content and extent of its core exceed the predictions of existing models of stellar evolution. The central homogeneous core has a mass of 0.45 solar masses, and is composed of about 86 per cent oxygen by mass. These values are respectively 40 per cent and 15 per cent greater than those expected from typical white-dwarf models. These findings challenge present theories of stellar evolution and their constitutive physics, and open up an avenue for calibrating white-dwarf cosmochronology.

A large oxygen-dominated core from the seismic cartography of a pulsating white dwarf.

PubMed

Giammichele, N; Charpinet, S; Fontaine, G; Brassard, P; Green, E M; Van Grootel, V; Bergeron, P; Zong, W; Dupret, M-A

2018-02-01

White-dwarf stars are the end product of stellar evolution for most stars in the Universe. Their interiors bear the imprint of fundamental mechanisms that occur during stellar evolution. Moreover, they are important chronometers for dating galactic stellar populations, and their mergers with other white dwarfs now appear to be responsible for producing the type Ia supernovae that are used as standard cosmological candles. However, the internal structure of white-dwarf stars-in particular their oxygen content and the stratification of their cores-is still poorly known, because of remaining uncertainties in the physics involved in stellar modelling codes. Here we report a measurement of the radial chemical stratification (of oxygen, carbon and helium) in the hydrogen-deficient white-dwarf star KIC08626021 (J192904.6+444708), independently of stellar-evolution calculations. We use archival data coupled with asteroseismic sounding techniques to determine the internal constitution of this star. We find that the oxygen content and extent of its core exceed the predictions of existing models of stellar evolution. The central homogeneous core has a mass of 0.45 solar masses, and is composed of about 86 per cent oxygen by mass. These values are respectively 40 per cent and 15 per cent greater than those expected from typical white-dwarf models. These findings challenge present theories of stellar evolution and their constitutive physics, and open up an avenue for calibrating white-dwarf cosmochronology.

Cabin Air Quality On Board Mir and the International Space Station: A Comparison

NASA Technical Reports Server (NTRS)

Macatangay, Ariel; Perry, Jay L.

2007-01-01

The maintenance of the cabin atmosphere aboard spacecraft is critical not only to its habitability but also to its function. Ideally, air quality can be maintained by striking a proper balance between the generation and removal of contaminants. Both very dynamic processes, the balance between generation and removal can be difficult to maintain and control because the state of the cabin atmosphere is in constant evolution responding to different perturbations. Typically, maintaining a clean cabin environment on board crewed spacecraft and space habitats is the central function of the environmental control and life support (ECLS) system. While active air quality control equipment is deployed on board every vehicle to remove carbon dioxide, water vapor, and trace chemical components from the cabin atmosphere, perturbations associated with logistics, vehicle construction and maintenance, and ECLS system configuration influence the resulting cabin atmospheric quality. The air-quality data obtained from the International Space Station (ISS) and NASA-Mir programs provides a wealth of information regarding the maintenance of the cabin atmosphere aboard long-lived space habitats. A comparison of the composition of the trace chemical contaminant load is presented. Correlations between ground-based and in-flight operations that influence cabin atmospheric quality are identified and discussed, and observations on cabin atmospheric quality during the NASA-Mir expeditions and the International Space Station are explored.

Representation in dynamical agents.

PubMed

Ward, Ronnie; Ward, Robert

2009-04-01

This paper extends experiments by Beer [Beer, R. D. (1996). Toward the evolution of dynamical neural networks for minimally cognitive behavior. In P. Maes, M. Mataric, J. Meyer, J. Pollack, & S. Wilson (Eds.), From animals to animats 4: Proceedings of the fourth international conference on simulation of adaptive behavior (pp. 421-429). MIT Press; Beer, R. D. (2003). The dynamics of active categorical perception in an evolved model agent (with commentary and response). Adaptive Behavior, 11 (4), 209-243] with an evolved, dynamical agent to further explore the question of representation in cognitive systems. Beer's environmentally-situated visual agent was controlled by a continuous-time recurrent neural network, and evolved to perform a categorical perception task, discriminating circles from diamonds. Despite the agent's high levels of discrimination performance, Beer found no evidence of internal representation in the best-evolved agent's nervous system. Here we examine the generality of this result. We evolved an agent for shape discrimination, and performed extensive behavioral analyses to test for representation. In this case we find that agents developed to discriminate equal-width shapes exhibit what Clark [Clark, A. (1997). The dynamical challenge. Cognitive Science, 21 (4), 461-481] calls "weak-substantive representation". The agent had internal configurations that (1) were understandably related to the object in the environment, and (2) were functionally used in a task relevant way when the target was not visible to the agent.

Phylogenetics of tribe Orchideae (Orchidaceae: Orchidoideae) based on combined DNA matrices: inferences regarding timing of diversification and evolution of pollination syndromes

PubMed Central

Inda, Luis A.; Pimentel, Manuel; Chase, Mark W.

2012-01-01

Background and aims Tribe Orchideae (Orchidaceae: Orchidoideae) comprises around 62 mostly terrestrial genera, which are well represented in the Northern Temperate Zone and less frequently in tropical areas of both the Old and New Worlds. Phylogenetic relationships within this tribe have been studied previously using only nuclear ribosomal DNA (nuclear ribosomal internal transcribed spacer, nrITS). However, different parts of the phylogenetic tree in these analyses were weakly supported, and integrating information from different plant genomes is clearly necessary in orchids, where reticulate evolution events are putatively common. The aims of this study were to: (1) obtain a well-supported and dated phylogenetic hypothesis for tribe Orchideae, (ii) assess appropriateness of recent nomenclatural changes in this tribe in the last decade, (3) detect possible examples of reticulate evolution and (4) analyse in a temporal context evolutionary trends for subtribe Orchidinae with special emphasis on pollination systems. Methods The analyses included 118 samples, belonging to 103 species and 25 genera, for three DNA regions (nrITS, mitochondrial cox1 intron and plastid rpl16 intron). Bayesian and maximum-parsimony methods were used to construct a well-supported and dated tree. Evolutionary trends in the subtribe were analysed using Bayesian and maximum-likelihood methods of character evolution. Key Results The dated phylogenetic tree strongly supported the recently recircumscribed generic concepts of Bateman and collaborators. Moreover, it was found that Orchidinae have diversified in the Mediterranean basin during the last 15 million years, and one potential example of reticulate evolution in the subtribe was identified. In Orchidinae, pollination systems have shifted on numerous occasions during the last 23 million years. Conclusions The results indicate that ancestral Orchidinae were hymenopteran-pollinated, food-deceptive plants and that these traits have been dominant throughout the evolutionary history of the subtribe in the Mediterranean. Evidence was also obtained that the onset of sexual deception might be linked to an increase in labellum size, and the possibility is discussed that diversification in Orchidinae developed in parallel with diversification of bees and wasps from the Miocene onwards. PMID:22539542

Engineering a Solution to Jupiter Exploration

NASA Technical Reports Server (NTRS)

Clark, Karla; Magner, Thomas; Lisano, Michael; Pappalardo, Robert

2010-01-01

The Europa Jupiter System Mission (EJSM) would be an international mission with the overall theme of investigating the emergence of habitable worlds around gas giants. Its goals are to (1) explore Europa to investigate its habitability, (2) characterize Ganymede as a planetary object including its potential habitability and (3) explore the Jupiter system as an archetype for gas giants. NASA and ESA have concluded a detailed joint study of a mission to Europa, Ganymede, and the Jupiter system with conceptual orbiters developed by NASA and ESA. The baseline EJSM architecture consists of two primary elements operating simultaneously in the Jovian system: the NASA-led Jupiter Europa Orbiter (JEO), and the ESA-led Jupiter Ganymede Orbiter (JGO). JEO and JGO would execute an intricately choreographed exploration of the Jupiter System before settling into orbit around Europa and Ganymede, respectively. EJSM would directly address themes concerning the origin and evolution of satellite systems and water-rich environments in icy satellites. The potential habitability of the ocean-bearing moons Europa and Ganymede would be investigated, by characterizing the geophysical, compositional, geological, and external processes that affect these icy worlds. EJSM would also investigate Io and Callisto, Jupiter's atmosphere, and the Jovian magnetosphere. By understanding the Jupiter system and unraveling its history, the formation and evolution of gas giant planets and their satellites would be better known. Most importantly, EJSM would shed new light on the potential for the emergence of life in the celestial neighborhood and beyond. The EJSM baseline architecture would provide opportunities for coordinated synergistic observations by JEO and JGO of the Jupiter and Ganymede magnetospheres, the volcanoes and torus of Io, the atmosphere of Jupiter, and comparative planetology of icy satellites. Each spacecraft would conduct both synergistic dual-spacecraft investigations and stand-alone measurements toward the overall mission theme and goals.

[The motive force of evolution based on the principle of organismal adjustment evolution.].

PubMed

Cao, Jia-Shu

2010-08-01

From the analysis of the existing problems of the prevalent theories of evolution, this paper discussed the motive force of evolution based on the knowledge of the principle of organismal adjustment evolution to get a new understanding of the evolution mechanism. In the guide of Schrodinger's theory - "life feeds on negative entropy", the author proposed that "negative entropy flow" actually includes material flow, energy flow and information flow, and the "negative entropy flow" is the motive force for living and development. By modifying my own theory of principle of organismal adjustment evolution (not adaptation evolution), a new theory of "regulation system of organismal adjustment evolution involved in DNA, RNA and protein interacting with environment" is proposed. According to the view that phylogenetic development is the "integral" of individual development, the difference of negative entropy flow between organisms and environment is considered to be a motive force for evolution, which is a new understanding of the mechanism of evolution. Based on such understanding, evolution is regarded as "a changing process that one subsystem passes all or part of its genetic information to the next generation in a larger system, and during the adaptation process produces some new elements, stops some old ones, and thereby lasts in the larger system". Some other controversial questions related to evolution are also discussed.

Challenges in Preparing Veterinarians for Global Animal Health: Understanding the Public Sector.

PubMed

Hollier, Paul J; Quinn, Kaylee A; Brown, Corrie C

Understanding of global systems is essential for veterinarians seeking to work in realms outside of their national domain. In the global system, emphasis remains on the public sector, and the current curricular emphasis in developed countries is on private clinical practice for the domestic employment market. There is a resulting lack of competency at graduation for effective engagement internationally. The World Organisation for Animal Health (OIE) has created standards for public sector operations in animal health, which must be functional to allow for sustainable development. This public sector, known as the Veterinary Services, or VS, serves to control public good diseases, and once effectively built and fully operational, allows for the evolution of a functional private sector, focused on private good diseases. Until the VS is fully functional, support of private good services is non-sustainable and any efforts delivered are not long lasting. As new graduates opt for careers working in the international development sector, it is essential that they understand the OIE guidelines to help support continuing improvement. Developing global veterinarians by inserting content into the veterinary curriculum on how public systems can operate effectively could markedly increase the potential of our professional contributions globally, and particularly in the areas most in need.

Assessment of electrochemical properties of a biogalvanic system for tissue characterisation

PubMed Central

Chandler, J.H.; Culmer, P.R.; Jayne, D.G.; Neville, A.

2015-01-01

Biogalvanic characterisation is a promising method for obtaining health-specific tissue information. However, there is a dearth of understanding in the literature regarding the underlying galvanic cell, electrode reactions and their controlling factors which limits the application of the technique. This work presents a parametric electrochemical investigation into a zinc–copper galvanic system using salt (NaCl) solution analogues at physiologically-relevant concentrations (1.71, 17.1 & 154 mM). The potential difference at open cell, closed cell maximum current and the internal resistance (based on published characterisation methods) were measured. Additionally, independent and relative polarisation scans of the electrodes were performed to improve understanding of the system. Our findings suggest that the prominent reaction at the cathode is that of oxygen-reduction, not hydrogen-evolution. Results indicate that cell potentials are influenced by the concentration of dissolved oxygen at low currents and maximum closed cell currents are limited by the rate of oxygen diffusion to the cathode. Characterised internal resistance values for the salt solutions did not correspond to theoretical values at the extremes of concentration (1.71 and 154 mM) due to electrode resistance and current limitation. Existing biogalvanic models do not consider these phenomena and should be improved to advance the technique and its practical application. PMID:25460609