Science.gov

Sample records for anderson quin cycle

  1. Quine and the Segregrational Sign.

    ERIC Educational Resources Information Center

    Wolf, George

    1999-01-01

    In the context of theory of integrational linguistics, the segregational sign is distinguished from the integrational sign, and the operation of the former is analyzed. Focus is on how logic guides the sign, and how the theory of W. V. Quine accounts for these issues. (MSE)

  2. Anderson Localization of Solitons

    NASA Astrophysics Data System (ADS)

    Sacha, Krzysztof; Müller, Cord A.; Delande, Dominique; Zakrzewski, Jakub

    2009-11-01

    At low temperature, a quasi-one-dimensional ensemble of atoms with an attractive interaction forms a bright soliton. When exposed to a weak and smooth external potential, the shape of the soliton is hardly modified, but its center-of-mass motion is affected. We show that in a spatially correlated disordered potential, the quantum motion of a bright soliton displays Anderson localization. The localization length can be much larger than the soliton size and could be observed experimentally.

  3. Anderson Localization of Solitons

    SciTech Connect

    Sacha, Krzysztof; Zakrzewski, Jakub; Mueller, Cord A.; Delande, Dominique

    2009-11-20

    At low temperature, a quasi-one-dimensional ensemble of atoms with an attractive interaction forms a bright soliton. When exposed to a weak and smooth external potential, the shape of the soliton is hardly modified, but its center-of-mass motion is affected. We show that in a spatially correlated disordered potential, the quantum motion of a bright soliton displays Anderson localization. The localization length can be much larger than the soliton size and could be observed experimentally.

  4. Kondo-Anderson transitions

    NASA Astrophysics Data System (ADS)

    Kettemann, S.; Mucciolo, E. R.; Varga, I.; Slevin, K.

    2012-03-01

    Dilute magnetic impurities in a disordered Fermi liquid are considered close to the Anderson metal-insulator transition (AMIT). Critical power-law correlations between electron wave functions at different energies in the vicinity of the AMIT result in the formation of pseudogaps of the local density of states. Magnetic impurities can remain unscreened at such sites. We determine the density of the resulting free magnetic moments in the zero-temperature limit. While it is finite on the insulating side of the AMIT, it vanishes at the AMIT, and decays with a power law as function of the distance to the AMIT. Since the fluctuating spins of these free magnetic moments break the time-reversal symmetry of the conduction electrons, we find a shift of the AMIT, and the appearance of a semimetal phase. The distribution function of the Kondo temperature TK is derived at the AMIT, in the metallic phase, and in the insulator phase. This allows us to find the quantum phase diagram in an external magnetic field B and at finite temperature T. We calculate the resulting magnetic susceptibility, the specific heat, and the spin relaxation rate as a function of temperature. We find a phase diagram with finite-temperature transitions among insulator, critical semimetal, and metal phases. These new types of phase transitions are caused by the interplay between Kondo screening and Anderson localization, with the latter being shifted by the appearance of the temperature-dependent spin-flip scattering rate. Accordingly, we name them Kondo-Anderson transitions.

  5. Anderson attractors in active arrays

    PubMed Central

    Laptyeva, Tetyana V.; Tikhomirov, Andrey A.; Kanakov, Oleg I.; Ivanchenko, Mikhail V.

    2015-01-01

    In dissipationless linear media, spatial disorder induces Anderson localization of matter, light, and sound waves. The addition of nonlinearity causes interaction between the eigenmodes, which results in a slow wave diffusion. We go beyond the dissipationless limit of Anderson arrays and consider nonlinear disordered systems that are subjected to the dissipative losses and energy pumping. We show that the Anderson modes of the disordered Ginsburg-Landau lattice possess specific excitation thresholds with respect to the pumping strength. When pumping is increased above the threshold for the band-edge modes, the lattice dynamics yields an attractor in the form of a stable multi-peak pattern. The Anderson attractor is the result of a joint action by the pumping-induced mode excitation, nonlinearity-induced mode interactions, and dissipative stabilization. The regimes of Anderson attractors can be potentially realized with polariton condensates lattices, active waveguide or cavity-QED arrays. PMID:26304462

  6. Quantifying Anderson's fault types

    USGS Publications Warehouse

    Simpson, R.W.

    1997-01-01

    Anderson [1905] explained three basic types of faulting (normal, strike-slip, and reverse) in terms of the shape of the causative stress tensor and its orientation relative to the Earth's surface. Quantitative parameters can be defined which contain information about both shape and orientation [Ce??le??rier, 1995], thereby offering a way to distinguish fault-type domains on plots of regional stress fields and to quantify, for example, the degree of normal-faulting tendencies within strike-slip domains. This paper offers a geometrically motivated generalization of Angelier's [1979, 1984, 1990] shape parameters ?? and ?? to new quantities named A?? and A??. In their simple forms, A?? varies from 0 to 1 for normal, 1 to 2 for strike-slip, and 2 to 3 for reverse faulting, and A?? ranges from 0?? to 60??, 60?? to 120??, and 120?? to 180??, respectively. After scaling, A?? and A?? agree to within 2% (or 1??), a difference of little practical significance, although A?? has smoother analytical properties. A formulation distinguishing horizontal axes as well as the vertical axis is also possible, yielding an A?? ranging from -3 to +3 and A?? from -180?? to +180??. The geometrically motivated derivation in three-dimensional stress space presented here may aid intuition and offers a natural link with traditional ways of plotting yield and failure criteria. Examples are given, based on models of Bird [1996] and Bird and Kong [1994], of the use of Anderson fault parameters A?? and A?? for visualizing tectonic regimes defined by regional stress fields. Copyright 1997 by the American Geophysical Union.

  7. The Ecological Approach to Language Development: A Radical Solution to Chomsky's and Quine's Problems.

    ERIC Educational Resources Information Center

    Reed, Edward S.

    1995-01-01

    Asserts that several of the assumptions underlying Noam Chomsky's and W. V. O. Quine's theories of language acquisition and development are misleading or false. It is argued, among other things, that children do not "acquire" language, but rather learn how to participate in the linguistic community surrounding them. (99 references) (MDM)

  8. Photophysical study of the Ca 2+-chelator QUIN 2 ligand: effect of divalent and trivalent cations

    NASA Astrophysics Data System (ADS)

    Guardigli, M.; Sabbatini, N.

    1991-05-01

    The photophysical properties of complexes of the Ca 2+-chelator QUIN 2 ligand with divalent and trivalent cations have been studied. The absorption of the ligand is almost independent of the nature of the complexing cations, while the fluorescence emission strongly depends on the electric charge of the cations. Metal emission upon excitation in the ligand has been observed for the Eu 3+ complex, but not for the Tb 3+ complex.

  9. Anderson localization from classical trajectories

    NASA Astrophysics Data System (ADS)

    Brouwer, Piet W.; Altland, Alexander

    2008-08-01

    We show that Anderson localization in quasi-one-dimensional conductors with ballistic electron dynamics, such as an array of ballistic chaotic cavities connected via ballistic contacts, can be understood in terms of classical electron trajectories only. At large length scales, an exponential proliferation of trajectories of nearly identical classical action generates an abundance of interference terms, which eventually leads to a suppression of transport coefficients. We quantitatively describe this mechanism in two different ways: the explicit description of transition probabilities in terms of interfering trajectories, and an hierarchical integration over fluctuations in the classical phase space of the array cavities.

  10. QuIN: A Web Server for Querying and Visualizing Chromatin Interaction Networks

    PubMed Central

    Thibodeau, Asa; Márquez, Eladio J.; Luo, Oscar; Ruan, Yijun; Shin, Dong-Guk; Stitzel, Michael L.; Ucar, Duygu

    2016-01-01

    Recent studies of the human genome have indicated that regulatory elements (e.g. promoters and enhancers) at distal genomic locations can interact with each other via chromatin folding and affect gene expression levels. Genomic technologies for mapping interactions between DNA regions, e.g., ChIA-PET and HiC, can generate genome-wide maps of interactions between regulatory elements. These interaction datasets are important resources to infer distal gene targets of non-coding regulatory elements and to facilitate prioritization of critical loci for important cellular functions. With the increasing diversity and complexity of genomic information and public ontologies, making sense of these datasets demands integrative and easy-to-use software tools. Moreover, network representation of chromatin interaction maps enables effective data visualization, integration, and mining. Currently, there is no software that can take full advantage of network theory approaches for the analysis of chromatin interaction datasets. To fill this gap, we developed a web-based application, QuIN, which enables: 1) building and visualizing chromatin interaction networks, 2) annotating networks with user-provided private and publicly available functional genomics and interaction datasets, 3) querying network components based on gene name or chromosome location, and 4) utilizing network based measures to identify and prioritize critical regulatory targets and their direct and indirect interactions. AVAILABILITY: QuIN’s web server is available at http://quin.jax.org QuIN is developed in Java and JavaScript, utilizing an Apache Tomcat web server and MySQL database and the source code is available under the GPLV3 license available on GitHub: https://github.com/UcarLab/QuIN/. PMID:27336171

  11. 27 CFR 9.86 - Anderson Valley.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Anderson Valley. 9.86 Section 9.86 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY ALCOHOL AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.86 Anderson Valley. (a) Name. The name of...

  12. Anderson and Condensed Matter Physics

    NASA Astrophysics Data System (ADS)

    Ramakrishnan, T. V.

    The legacy of P. W. Anderson, perhaps the most fertile and influential condensed matter physicist of the second half of the twentieth century, is briefly mentioned here. I note three pervasive values. They are: emergence with its constant tendency to surprise us and to stretch our imagination, the Baconian emphasis on the experimental moorings of modern science, and mechanism as the explanatory core. Out of his work, which is spread over more than six decades and in many ways has charted modern condensed matter physics, nearly a dozen seminal contributions, chosen idiosyncratically, are mentioned at the risk of leaving out many which may also have started subfields. Some of these are: antiferromagnestism and broken symmetry, superexchange and strong electron correlations, localization in disordered systems, gauge invariance and mass, and the resonating valence bond in magnetic systems as well as in high-temperature superconductivity...

  13. Calcium transport by ionophorous peptides in dog and human lymphocytes detected by quin-2 fluorescence.

    PubMed

    Deber, C M; Hsu, L C

    1986-01-29

    Synthetic peptides of structure cyclo(Glu(OBz)-Sar-Gly-(N-R)Gly)2 (I), electrogenic Ca2+-selective carriers in phospholipid vesicle membranes, are shown to mediate the uptake of Ca2+ ions into the cytoplasm of dog and human lymphocytes. Ca2+ transport by DECYL-2E (I, R = n-decyl) - monitored by measurements of the fluorescence of an intracellular dye, quin-2 - occurred at a rate comparable to that produced by electroneutral Ca2+ ionophores ionomycin and Br-A23187. Fluorescence quenching experiments using Mn2+ suggested a greater selectivity by DECYL-2E for Ca2+/Mn2+ vs. the other two ionophores. The result that Ca2+ ions can traverse biological membranes bound in a neutral cavity consisting exclusively of peptide carbonyl ligands may imply the functional significance of binding sites of similar structures in membrane transport proteins. PMID:3947349

  14. Anderson localization in metallic nanoparticle arrays

    NASA Astrophysics Data System (ADS)

    Mai, Zhijie; Lin, Fang; Pang, Wei; Xu, Haitao; Tan, Suiyan; Fu, Shenhe; Li, Yongyao

    2016-06-01

    Anderson localization has been observed in various types of waves, such as matter waves, optical waves and acoustic waves. Here we reveal that the effect of Anderson localization can be also induced in metallic nonlinear nanoparticle arrays excited by a random electrically driving field. We find that the dipole-induced nonlinearity results in ballistic expansion of dipole intensity during evolution; while the randomness of the external driving field can suppress such an expansion. Increasing the strength of randomness above the threshold value, a localized pattern of dipole intensity can be generated in the metallic nanoparticle arrays. By means of statistics, the mean intensity distribution of the dipoles reveals the formation of Anderson localization. We further show that the generated Anderson localization is highly confined, with its size down to the scale of incident wavelength. The reported results might facilitate the manipulations of electromagnetic fields in the scale of wavelength.

  15. Anderson localization in metallic nanoparticle arrays.

    PubMed

    Mai, Zhijie; Lin, Fang; Pang, Wei; Xu, Haitao; Tan, Suiyan; Fu, Shenhe; Li, Yongyao

    2016-06-13

    Anderson localization has been observed in various types of waves, such as matter waves, optical waves and acoustic waves. Here we reveal that the effect of Anderson localization can be also induced in metallic nonlinear nanoparticle arrays excited by a random electrically driving field. We find that the dipole-induced nonlinearity results in ballistic expansion of dipole intensity during evolution; while the randomness of the external driving field can suppress such an expansion. Increasing the strength of randomness above the threshold value, a localized pattern of dipole intensity can be generated in the metallic nanoparticle arrays. By means of statistics, the mean intensity distribution of the dipoles reveals the formation of Anderson localization. We further show that the generated Anderson localization is highly confined, with its size down to the scale of incident wavelength. The reported results might facilitate the manipulations of electromagnetic fields in the scale of wavelength. PMID:27410338

  16. Taking on Titan: Meet Carrie Anderson

    NASA Video Gallery

    When she was a little girl, Carrie Anderson dreamed of becoming an astronomer. Now, as a space scientist at NASA Goddard Space Flight Center, Carrie studies the atmosphere on Titan: one of Saturn's...

  17. Coherent Backscattering Reveals the Anderson Transition.

    PubMed

    Ghosh, S; Delande, D; Miniatura, C; Cherroret, N

    2015-11-13

    We develop an accurate finite-time scaling analysis of the angular width of the coherent backscattering (CBS) peak for waves propagating in 3D random media. Applying this method to ultracold atoms in optical speckle potentials, we show how to determine both the mobility edge and the critical exponent of the Anderson transition from the temporal behavior of the CBS width. Our method could be used in experiments to fully characterize the 3D Anderson transition. PMID:26613427

  18. Coherent Backscattering Reveals the Anderson Transition

    NASA Astrophysics Data System (ADS)

    Ghosh, S.; Delande, D.; Miniatura, C.; Cherroret, N.

    2015-11-01

    We develop an accurate finite-time scaling analysis of the angular width of the coherent backscattering (CBS) peak for waves propagating in 3D random media. Applying this method to ultracold atoms in optical speckle potentials, we show how to determine both the mobility edge and the critical exponent of the Anderson transition from the temporal behavior of the CBS width. Our method could be used in experiments to fully characterize the 3D Anderson transition.

  19. Pyrene-Anderson-Modified CNTs as Anode Materials for Lithium-Ion Batteries.

    PubMed

    Huang, Lujiang; Hu, Jun; Ji, Yuanchun; Streb, Carsten; Song, Yu-Fei

    2015-12-14

    An organo-functionalized polyoxometalate (POM)-pyrene hybrid (Py-Anderson) has been used for noncovalent functionalization of carbon nanotubes (CNTs) to give a Py-Anderson-CNT nanocomposite through π-π interactions. The as-synthesized nanocomposite was used as the anode material for lithium-ion batteries, and shows higher discharge capacities and better rate capacity and cycling stability than the individual components. When the current density was 0.5 mA cm(-2), the nanocomposite exhibited an initial discharge capacity of 1898.5 mA h g(-1) and a high discharge capacity of 665.3 mA h g(-1) for up to 100 cycles. AC impedance spectroscopy provides insight into the electrochemical properties and the charge-transfer mechanism of the Py-Anderson-CNTs electrode. PMID:26538031

  20. Schemata, Cognitive Structure, and Advance Organizers: A Reply to Anderson, Spiro, and Anderson.

    ERIC Educational Resources Information Center

    Ausubel, David P.

    1980-01-01

    Anderson, Spiro, and Anderson (EJ 189 658) assert that the author's assimilation theory of meaningful learning and retention is "hopelessly vague." Documented examination of these assertions indicates that they are unspecified, unsubstantiated, undocumented, and based on indisputable misrepresentation of published material and on logical non…

  1. Universality and the QCD Anderson transition.

    PubMed

    Giordano, Matteo; Kovács, Tamás G; Pittler, Ferenc

    2014-03-14

    We study the Anderson-type transition previously found in the spectrum of the QCD quark Dirac operator in the high-temperature, quark-gluon plasma phase. Using finite size scaling for the unfolded level spacing distribution, we show that in the thermodynamic limit there is a genuine mobility edge, where the spectral statistics changes from Poisson to Wigner-Dyson statistics in a nonanalytic way. We determine the correlation length critical exponent ν and find that it is compatible with that of the unitary Anderson model. PMID:24679282

  2. Low shear viscosity due to Anderson localization

    SciTech Connect

    Giannakis, Ioannis; Hou Defu; Ren Haicang; Li Jiarong

    2008-01-15

    We study the Anderson localization effect on the shear viscosity in a system with random medium by Kubo formula. We show that this effect can suppress nonperturbatively the shear viscosity and other transport coefficients. The possible relevancy of such a suppression to the near perfect fluid behavior of the quark-gluon plasma created in heavy-ion collisions is discussed.

  3. The Châtelperronian conundrum: Blade and bladelet lithic technologies from Quinçay, France.

    PubMed

    Roussel, M; Soressi, M; Hublin, J-J

    2016-06-01

    The discovery of an almost complete Neanderthal skeleton in a Châtelperronian context at Saint-Césaire 35 years ago changed our perspective on the beginning of the Upper Paleolithic in western Europe. Since then, the Châtelperronian has generally been considered a "transitional" industry rather than an Upper or a Middle Paleolithic industry because of its chronological position, and the association of Neanderthal remains with blades, bone tools and personal ornaments. Several competing hypotheses have been proposed to explain the association between Neanderthals and these types of artefacts including post-depositional mixing, acculturation from anatomically modern human populations, or an independent technological evolution by local Neanderthal populations. Quinçay Cave is the only Châtelperronian site where personal ornaments have been found that does not contain an overlying Upper Paleolithic layer. This means that the post-depositional mixing of later elements into the Châtelperronian may not be used as an explanation for the presence of these materials. We report here on a detailed technological analysis of lithic artefacts from the three Châtelperronian layers at Quinçay Cave. We compare our results with the technology of Mousterian blade industries dating to OIS (oxygen isotope stage) 5, the Mousterian of Acheulian Tradition type B, and the Proto-Aurignacian. We show that the Châtelperronian is sufficiently divergent from the Middle Paleolithic to be classified as a fully Upper Paleolithic industry, with a focus on blade and bladelet production. We also show that the Quinçay Châtelperronian includes retouched bladelets that resemble those found in the Proto-Aurignacian, but were produced in a different manner. We argue that a technological convergence cannot account for these behaviors, since the specific type of retouched bladelet associated with the Châtelperronian was also regularly used by Proto-Aurignacian of neighboring regions. We suggest

  4. Anderson localization for chemically realistic systems

    NASA Astrophysics Data System (ADS)

    Terletska, Hanna

    2015-03-01

    Disorder which is ubiquitous for most materials can strongly effect their properties. It may change their electronic structures or even cause their localization, known as Anderson localization. Although, substantial progress has been achieved in the description of the Anderson localization, a proper mean-field theory of this phenomenon for more realistic systems remains elusive. Commonly used theoretical methods such as the coherent potential approximation and its cluster extensions fail to describe the Anderson transition, as the average density of states (DOS) employed in such theories is not critical at the transition. However, near the transition, due to the spatial confinement of carriers, the local DOS becomes highly skewed with a log-normal distribution, for which the most probable and the typical values differ noticeably from the average value. Dobrosavljevic et.al., incorporated such ideas in their typical medium theory (TMT), and showed that the typical (not average) DOS is critical at the transition. While the TMT is able to capture the localized states, as a local single site theory it still has several drawbacks. For the disorder Anderson model in three dimension it underestimates the critical disorder strength, and fails to capture the re-entrance behavior of the mobility edge. We have recently developed a cluster extension of the TMT, which addresses these drawbacks by systematically incorporating non-local corrections. This approach converges quickly with cluster size and allows us to incorporate the effect of interactions and realistic electronic structure. As the first steps towards realistic material modeling, we extended our TMDCA formalisms to systems with the off diagonal disorder and multiple bands structures. We also applied our TMDCA scheme to systems with both disorder and interactions and found that correlations effects tend to stabilize the metallic behavior even in two dimensions. This work was supported by DOE SciDAC Grant No. DE-FC02

  5. Universal mechanism for Anderson and weak localization.

    PubMed

    Filoche, Marcel; Mayboroda, Svitlana

    2012-09-11

    Localization of stationary waves occurs in a large variety of vibrating systems, whether mechanical, acoustical, optical, or quantum. It is induced by the presence of an inhomogeneous medium, a complex geometry, or a quenched disorder. One of its most striking and famous manifestations is Anderson localization, responsible for instance for the metal-insulator transition in disordered alloys. Yet, despite an enormous body of related literature, a clear and unified picture of localization is still to be found, as well as the exact relationship between its many manifestations. In this paper, we demonstrate that both Anderson and weak localizations originate from the same universal mechanism, acting on any type of vibration, in any dimension, and for any domain shape. This mechanism partitions the system into weakly coupled subregions. The boundaries of these subregions correspond to the valleys of a hidden landscape that emerges from the interplay between the wave operator and the system geometry. The height of the landscape along its valleys determines the strength of the coupling between the subregions. The landscape and its impact on localization can be determined rigorously by solving one special boundary problem. This theory allows one to predict the localization properties, the confining regions, and to estimate the energy of the vibrational eigenmodes through the properties of one geometrical object. In particular, Anderson localization can be understood as a special case of weak localization in a very rough landscape. PMID:22927384

  6. Phil Anderson's Magnetic Ideas in Science

    NASA Astrophysics Data System (ADS)

    Coleman, Piers

    In Philip W. Anderson's research, magnetism has always played a special role, providing a prism through which other more complex forms of collective behavior and broken symmetry could be examined. I discuss his work on magnetism from the 1950s, where his early work on antiferromagnetism led to the pseudospin treatment of superconductivity -- to the 1970s and 1980s, highlighting his contribution to the physics of local magnetic moments. Phil's interest in the mechanism of moment formation, and screening evolved into the modern theory of the Kondo effect and heavy fermions.

  7. Anderson transition for Google matrix eigenstates

    NASA Astrophysics Data System (ADS)

    Zhirov, O. V.; Shepelyansky, D. L.

    2015-10-01

    We introduce a number of random matrix models describing the Google matrix G of directed networks. The properties of their spectra and eigenstates are analyzed by numerical matrix diagonalization. We show that for certain models it is possible to have an algebraic decay of PageRank vector with the exponent similar to real directed networks. At the same time the spectrum has no spectral gap and a broad distribution of eigenvalues in the complex plain. The eigenstates of G are characterized by the Anderson transition from localized to delocalized states and a mobility edge curve in the complex plane of eigenvalues.

  8. Astronaut Clay Anderson Speaks With S.C. Students

    NASA Video Gallery

    From NASA's International Space Station Mission Control Center, NASA astronaut Clay Anderson participates in a Digital Learning Network (DLN) event with students at Crayton Middle School, Columbia,...

  9. Distribution of critical temperature at Anderson localization

    NASA Astrophysics Data System (ADS)

    Gammag, Rayda; Kim, Ki-Seok

    2016-05-01

    Based on a local mean-field theory approach at Anderson localization, we find a distribution function of critical temperature from that of disorder. An essential point of this local mean-field theory approach is that the information of the wave-function multifractality is introduced. The distribution function of the Kondo temperature (TK) shows a power-law tail in the limit of TK→0 regardless of the Kondo coupling constant. We also find that the distribution function of the ferromagnetic transition temperature (Tc) gives a power-law behavior in the limit of Tc→0 when an interaction parameter for ferromagnetic instability lies below a critical value. However, the Tc distribution function stops the power-law increasing behavior in the Tc→0 limit and vanishes beyond the critical interaction parameter inside the ferromagnetic phase. These results imply that the typical Kondo temperature given by a geometric average always vanishes due to finite density of the distribution function in the TK→0 limit while the typical ferromagnetic transition temperature shows a phase transition at the critical interaction parameter. We propose that the typical transition temperature serves a criterion for quantum Griffiths phenomena vs smeared transitions: Quantum Griffiths phenomena occur above the typical value of the critical temperature while smeared phase transitions result at low temperatures below the typical transition temperature. We speculate that the ferromagnetic transition at Anderson localization shows the evolution from quantum Griffiths phenomena to smeared transitions around the critical interaction parameter at low temperatures.

  10. Note on Anderson's "Causal Models in Educational Research: Nonrecursive Models."

    ERIC Educational Resources Information Center

    Shapiro, Jonathan

    1979-01-01

    Contrary to Anderson (EJ 187 936), his rule for equation identification is a necessary but not sufficient condition; furthermore, the choice of two-stage or ordinary least squares depends on results and not on methodological properties of estimators. Modification of Anderson's rule and a means for choosing between estimates is offered. (Author/CP)

  11. Slow Relaxation in Anderson Critical Systems

    NASA Astrophysics Data System (ADS)

    Choi, Soonwon; Yao, Norman; Choi, Joonhee; Kucsko, Georg; Lukin, Mikhail

    2016-05-01

    We study the single particle dynamics in disordered systems with long range hopping, focusing on the critical cases, i.e., the hopping amplitude decays as 1 /rd in d-dimension. We show that with strong on-site potential disorder, the return probability of the particle decays as power-law in time. As on-site potential disorder decreases, the temporal profile smoothly changes from a simple power-law to the sum of multiple power-laws with exponents ranged from 0 to νmax. We analytically compute the decay exponents using a simple resonance counting argument, which quantitatively agrees with exact numerical results. Our result implies that the dynamics in Anderson Critical systems are dominated by resonances. Harvard-MIT CUA, Kwanjeong Educational Fellowship, AFOSR MURI, Samsung Scholarship.

  12. Magnetoresistance of an Anderson insulator of bosons.

    PubMed

    Gangopadhyay, Anirban; Galitski, Victor; Müller, Markus

    2013-07-12

    We study the magnetoresistance of two-dimensional bosonic Anderson insulators. We describe the change in spatial decay of localized excitations in response to a magnetic field, which is given by an interference sum over alternative tunneling trajectories. The excitations become more localized with increasing field (in sharp contrast to generic fermionic excitations which get weakly delocalized): the localization length ξ(B) is found to change as ξ(-1)(B)-ξ(-1)(0)~B(4/5). The quantum interference problem maps onto the classical statistical mechanics of directed polymers in random media (DPRM). We explain the observed scaling using a simplified droplet model which incorporates the nontrivial DPRM exponents. Our results have implications for a variety of experiments on magnetic-field-tuned superconductor-to-insulator transitions observed in disordered films, granular superconductors, and Josephson junction arrays, as well as for cold atoms in artificial gauge fields. PMID:23889427

  13. Energy transport in the Anderson insulator

    NASA Astrophysics Data System (ADS)

    Gutman, D. B.; Protopopov, I. V.; Burin, A. L.; Gornyi, I. V.; Santos, R. A.; Mirlin, A. D.

    2016-06-01

    We study the heat conductivity in Anderson insulators in the presence of a power-law interaction. Particle-hole excitations built on localized electron states are viewed as two-level systems randomly distributed in space and energy and coupled due to electron-electron interaction. A small fraction of these states form resonant pairs that in turn build a complex network allowing for energy propagation. We identify the character of energy transport through this network and evaluate the thermal conductivity. For physically relevant cases of two-dimensional and three-dimensional spin systems with 1 /r3 dipole-dipole interaction (originating from the conventional 1 /r Coulomb interaction between electrons), the found thermal conductivity κ scales with temperature as κ ∝T3 and κ ∝T4 /3 , respectively. Our results may be of relevance also to other realizations of random spin Hamiltonians with long-range interactions.

  14. Kolmogorov turbulence, Anderson localization and KAM integrability

    NASA Astrophysics Data System (ADS)

    Shepelyansky, D. L.

    2012-06-01

    The conditions for emergence of Kolmogorov turbulence, and related weak wave turbulence, in finite size systems are analyzed by analytical methods and numerical simulations of simple models. The analogy between Kolmogorov energy flow from large to small spacial scales and conductivity in disordered solid state systems is proposed. It is argued that the Anderson localization can stop such an energy flow. The effects of nonlinear wave interactions on such a localization are analyzed. The results obtained for finite size system models show the existence of an effective chaos border between the Kolmogorov-Arnold-Moser (KAM) integrability at weak nonlinearity, when energy does not flow to small scales, and developed chaos regime emerging above this border with the Kolmogorov turbulent energy flow from large to small scales.

  15. Anderson localization makes adiabatic quantum optimization fail

    PubMed Central

    Altshuler, Boris; Krovi, Hari; Roland, Jérémie

    2010-01-01

    Understanding NP-complete problems is a central topic in computer science (NP stands for nondeterministic polynomial time). This is why adiabatic quantum optimization has attracted so much attention, as it provided a new approach to tackle NP-complete problems using a quantum computer. The efficiency of this approach is limited by small spectral gaps between the ground and excited states of the quantum computer’s Hamiltonian. We show that the statistics of the gaps can be analyzed in a novel way, borrowed from the study of quantum disordered systems in statistical mechanics. It turns out that due to a phenomenon similar to Anderson localization, exponentially small gaps appear close to the end of the adiabatic algorithm for large random instances of NP-complete problems. This implies that unfortunately, adiabatic quantum optimization fails: The system gets trapped in one of the numerous local minima. PMID:20616043

  16. Aligning a reflection cavity by Anderson's method.

    PubMed

    Reasenberg, Robert D

    2012-06-01

    The sounding rocket principle of equivalence measurement uses a set of four laser gauges operating in Fabry-Perot cavities to determine the relative acceleration of two test masses that are chemically different. One end of each cavity is a flat mirror on a test mass. Because the test masses are unconstrained and thus expected to rotate slightly during measurement, and because the distance measurements are made at the sub-picometer level, it is essential to have real-time alignment of the beam entering the cavity. However, the cavity must be used in reflection and space is limited. We show that Anderson's alignment method can be used in reflection, but that it requires that the Fabry-Perot cavity have mirrors with significantly unequal reflectivities. PMID:22695543

  17. The Role of Contrast in the Perception of Achromatic Transparency: Comment on Singh and Anderson (2002) and Anderson (2003)

    ERIC Educational Resources Information Center

    Albert, Marc K.

    2008-01-01

    M. Singh and B. L. Anderson proposed a perceptual theory of achromatic transparency in which the perceived transmittance of a perceived transparent filter is determined by the ratio of the Michelson contrast seen in the region of transparency to that of the background seen directly. Subsequently, B. L. Anderson, M. Singh, and J. Meng proposed that…

  18. Thermalization processes in interacting Anderson insulators

    NASA Astrophysics Data System (ADS)

    Ovadyahu, Z.

    2015-01-01

    This paper describes experiments utilizing a unique property of electron glasses to gain information on the fundamental nature of the interacting Anderson-localized phase. The methodology is based on measuring the energy absorbed by the electronic system from alternating electromagnetic fields as a function of their frequency. Experiments on three-dimensional (3D) amorphous indium-oxide films suggest that, in the strongly localized regime, the energy spectrum is discrete and inelastic electron-electron events are strongly suppressed. These results imply that, at low temperatures, electron thermalization and finite conductivity depend on coupling to the phonon bath. The situation is different for samples nearing the metal-insulator transition; in insulating samples that are close to the mobility edge, energy absorption persists to much higher frequencies. Comparing these results with previously studied 2D samples [Ovadyahu, Phys. Rev. Lett. 108, 156602 (2012), 10.1103/PhysRevLett.108.156602] demonstrates that the mean-level spacing (on a single-particle basis) is not the only relevant scale in this problem. The possibility of delocalization by many-body effects and the relevance of a nearby mobility edge (which may be a many-body edge) are discussed.

  19. Topological approximation of the nonlinear Anderson model

    NASA Astrophysics Data System (ADS)

    Milovanov, Alexander V.; Iomin, Alexander

    2014-06-01

    We study the phenomena of Anderson localization in the presence of nonlinear interaction on a lattice. A class of nonlinear Schrödinger models with arbitrary power nonlinearity is analyzed. We conceive the various regimes of behavior, depending on the topology of resonance overlap in phase space, ranging from a fully developed chaos involving Lévy flights to pseudochaotic dynamics at the onset of delocalization. It is demonstrated that the quadratic nonlinearity plays a dynamically very distinguished role in that it is the only type of power nonlinearity permitting an abrupt localization-delocalization transition with unlimited spreading already at the delocalization border. We describe this localization-delocalization transition as a percolation transition on the infinite Cayley tree (Bethe lattice). It is found in the vicinity of the criticality that the spreading of the wave field is subdiffusive in the limit t →+∞. The second moment of the associated probability distribution grows with time as a power law ∝ tα, with the exponent α =1/3 exactly. Also we find for superquadratic nonlinearity that the analog pseudochaotic regime at the edge of chaos is self-controlling in that it has feedback on the topology of the structure on which the transport processes concentrate. Then the system automatically (without tuning of parameters) develops its percolation point. We classify this type of behavior in terms of self-organized criticality dynamics in Hilbert space. For subquadratic nonlinearities, the behavior is shown to be sensitive to the details of definition of the nonlinear term. A transport model is proposed based on modified nonlinearity, using the idea of "stripes" propagating the wave process to large distances. Theoretical investigations, presented here, are the basis for consistency analysis of the different localization-delocalization patterns in systems with many coupled degrees of freedom in association with the asymptotic properties of the

  20. Modified Anderson Model——Dynamics of Brittle Faulting

    NASA Astrophysics Data System (ADS)

    Tong, H.

    2014-12-01

    Anderson's model has been a basic theory of fault mechanical analysis in one century. However, because of the assumptions, there are some major limitations in Anderson model, and it does not account for frequently observed oblique slips, complicated fault cases in nature and the slips occurring on pre-existing planes of weakness. On the basis of Reactivation Tendency Analysis theory proposed by Tong and Yin (2011), we proposed Modified Anderson model and extended Anderson model from 1) homogeneous media to Inhomogeneous media with pre-existing weakness(es); 2) Andersonian stress state to arbitrary stress state; 3) transient activity trend analysis to fault formation and evolution, and verified with sandbox experiments and natural cases. With Modified Anderson model, we can predict 1) the sequence of fault formation; 2) fault orientations and distribution; 3) slip directions (dip slip, oblique-dip slip, oblique slip, oblique strike slip and strike sip) of different fault when the directions of principal stress, orientations and mechanical properties (cohesion and frictional coefficient) of pre-existing weakness(es) are given. The origin of the complicated fault systems in nature can be explained reasonably. There will be a wide applications for oil and gas exploration and development, coal mining, earthquake risk evaluation, etc.

  1. Anderson localization effects near the Mott metal-insulator transition

    NASA Astrophysics Data System (ADS)

    Bragança, Helena; Aguiar, M. C. O.; Vučičević, J.; Tanasković, D.; Dobrosavljević, V.

    2015-09-01

    The interplay between Mott and Anderson routes to localization in disordered interacting systems gives rise to different transitions and transport regimes. Here, we investigate the phase diagram at finite temperatures using dynamical mean-field theory combined with typical medium theory, which is an effective theory of the Mott-Anderson metal-insulator transition. We mainly focus on the properties of the coexistence region associated with the Mott phase transition. For weak disorder, the coexistence region is found to be similar to that in the clean case. However, as we increase disorder, Anderson localization effects are responsible for shrinking the coexistence region, and at sufficiently strong disorder (approximately equal to twice the bare bandwidth) it drastically narrows, the critical temperature Tc abruptly goes to zero, and we observe a phase transition in the absence of a coexistence of the metallic and insulating phases. In this regime, the effects of interaction and disorder are found to be of comparable importance for charge localization.

  2. The M. D. Anderson proton therapy system

    SciTech Connect

    Smith, Alfred; Gillin, Michael; Bues, Martin; Zhu, X. Ronald; Suzuki, Kazumichi; Mohan, Radhe; Woo, Shiao; Lee, Andrew; Komaki, Ritsko; Cox, James; Hiramoto, Kazuo; Akiyama, Hiroshi; Ishida, Takayuki; Sasaki, Toshie; Matsuda, Koji

    2009-09-15

    Purpose: The purpose of this study is to describe University of Texas M. D. Anderson proton therapy system (PTC-H) including the accelerator, beam transport, and treatment delivery systems, the functionality and clinical parameters for passive scattering and pencil beam scanning treatment modes, and the results of acceptance tests. Methods: The PTC-H has a synchrotron (70-250 MeV) and four treatment rooms. An overall control system manages the treatment, physics, and service modes of operation. An independent safety system ensures the safety of patients, staff, and equipment. Three treatment rooms have isocentric gantries and one room has two fixed horizontal beamlines, which include a large-field treatment nozzle, used primarily for prostate treatments, and a small-field treatment nozzle for ocular treatments. Two gantry treatment rooms and the fixed-beam treatment room have passive scattering nozzles. The third gantry has a pencil beam scanning nozzle for the delivery of intensity modulated proton treatments (IMPT) and single field uniform dose (SFUD) treatments. The PTC-H also has an experimental room with a fixed horizontal beamline and a passive scattering nozzle. The equipment described above was provided by Hitachi, Ltd. Treatment planning is performed using the Eclipse system from Varian Medical Systems and data management is handled by the MOSAIQ system from IMPAC Medical Systems, Inc. The large-field passive scattering nozzles use double scattering systems in which the first scatterers are physically integrated with the range modulation wheels. The proton beam is gated on the rotating range modulation wheels at gating angles designed to produce spread-out-Bragg peaks ranging in size from 2 to 16 g/cm{sup 2}. Field sizes of up to 25x25 cm{sup 2} can be achieved with the double scattering system. The IMPT delivery technique is discrete spot scanning, which has a maximum field size of 30x30 cm{sup 2}. Depth scanning is achieved by changing the energy

  3. An Anderson-like model of the QCD chiral transition

    NASA Astrophysics Data System (ADS)

    Giordano, Matteo; Kovács, Tamás G.; Pittler, Ferenc

    2016-06-01

    We study the problems of chiral symmetry breaking and eigenmode localisation in finite-temperature QCD by looking at the lattice Dirac operator as a random Hamiltonian. We recast the staggered Dirac operator into an unconventional three-dimensional Anderson Hamiltonian ("Dirac-Anderson Hamiltonian") carrying internal degrees of freedom, with disorder provided by the fluctuations of the gauge links. In this framework, we identify the features relevant to chiral symmetry restoration and localisation of the low-lying Dirac eigenmodes in the ordering of the local Polyakov lines, and in the related correlation between spatial links across time slices, thus tying the two phenomena to the deconfinement transition. We then build a toy model based on QCD and on the Dirac-Anderson approach, replacing the Polyakov lines with spin variables and simplifying the dynamics of the spatial gauge links, but preserving the above-mentioned relevant dynamical features. Our toy model successfully reproduces the main features of the QCD spectrum and of the Dirac eigenmodes concerning chiral symmetry breaking and localisation, both in the ordered (deconfined) and disordered (confined) phases. Moreover, it allows us to study separately the roles played in the two phenomena by the diagonal and the off-diagonal terms of the Dirac-Anderson Hamiltonian. Our results support our expectation that chiral symmetry restoration and localisation of the low modes are closely related, and that both are triggered by the deconfinement transition.

  4. Interpolation Processes in Object Perception: Reply to Anderson (2007)

    ERIC Educational Resources Information Center

    Kellman, Philip J.; Garrigan, Patrick; Shipley, Thomas F.; Keane, Brian P.

    2007-01-01

    P. J. Kellman, P. Garrigan, & T. F. Shipley presented a theory of 3-D interpolation in object perception. Along with results from many researchers, this work supports an emerging picture of how the visual system connects separate visible fragments to form objects. In his commentary, B. L. Anderson challenges parts of that view, especially the idea…

  5. 6. VIEW OF SITE A FROM ANDERSON WAY NEAR BUILDING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. VIEW OF SITE A FROM ANDERSON WAY NEAR BUILDING 132, FACING SOUTHEAST (BUILDINGS 124, 122, 120, and 118 ARE VISIBLE.) - Fort McPherson, World War II Station Hospital, Structures, Bordered by Hardee & Thorne Avenues & Howe Street, Atlanta, Fulton County, GA

  6. Scaling of the conductance distribution near the Anderson transition

    NASA Astrophysics Data System (ADS)

    Slevin, Keith; Markoš, Peter; Ohtsuki, Tomi

    2003-04-01

    The scaling hypothesis is the foundation of our understanding of the Anderson transition. We present a direct numerical demonstration of the scaling of the conductance distribution of a disordered system in the critical regime. This complements a previous demonstration of the scaling of certain averages of the conductance distribution [K. Slevin et al., Phys. Rev. Lett. 86, 3594 (2001)].

  7. Spectral density method to Anderson-Holstein model

    SciTech Connect

    Chebrolu, Narasimha Raju Chatterjee, Ashok

    2015-06-24

    Two-parameter spectral density function of a magnetic impurity electron in a non-magnetic metal is calculated within the framework of the Anderson-Holstein model using the spectral density approximation method. The effect of electron-phonon interaction on the spectral function is investigated.

  8. 9. VIEW OF SITE B FROM EAST END OF ANDERSON ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. VIEW OF SITE B FROM EAST END OF ANDERSON WAY, FACING WEST (BUILDINGS 126, 128, 129, 130, and 131 ARE VISIBLE.) - Fort McPherson, World War II Station Hospital, Structures, Bordered by Hardee & Thorne Avenues & Howe Street, Atlanta, Fulton County, GA

  9. 10. VIEW OF SITE B FROM WEST END OF ANDERSON ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. VIEW OF SITE B FROM WEST END OF ANDERSON WAY, FACING NORTHEAST (BUILDINGS 131, 130, 129, and 128 ARE VISIBLE.) - Fort McPherson, World War II Station Hospital, Structures, Bordered by Hardee & Thorne Avenues & Howe Street, Atlanta, Fulton County, GA

  10. Anderson localization of graphene by helium ion irradiation

    NASA Astrophysics Data System (ADS)

    Naitou, Y.; Ogawa, S.

    2016-04-01

    Irradiation of a single-layer graphene (SLG) with accelerated helium ions (He+) controllably generates defect distributions, which create a charge carrier scattering source within the SLG. We report direct experimental observation of metal-insulator transition in SLG on SiO2/Si substrates induced by Anderson localization. This transition was investigated using scanning capacitance microscopy by monitoring the He+ dose conditions on the SLG. The experimental data show that a defect density of more than ˜1.2% induced Anderson localization. We also investigated the localization length by determining patterned placement of the defects and estimated the length to be several dozen nanometers. These findings provide valuable insight for patterning and designing graphene-based nanostructures using helium ion microscopy.

  11. Anderson localization on the Bethe lattice: nonergodicity of extended States.

    PubMed

    De Luca, A; Altshuler, B L; Kravtsov, V E; Scardicchio, A

    2014-07-25

    Statistical analysis of the eigenfunctions of the Anderson tight-binding model with on-site disorder on regular random graphs strongly suggests that the extended states are multifractal at any finite disorder. The spectrum of fractal dimensions f(α) defined in Eq. (3) remains positive for α noticeably far from 1 even when the disorder is several times weaker than the one which leads to the Anderson localization; i.e., the ergodicity can be reached only in the absence of disorder. The one-particle multifractality on the Bethe lattice signals on a possible inapplicability of the equipartition law to a generic many-body quantum system as long as it remains isolated. PMID:25105646

  12. Ground-state properties of the periodic Anderson model

    NASA Technical Reports Server (NTRS)

    Blankenbecler, R.; Fulco, J. R.; Gill, W.; Scalapino, D. J.

    1987-01-01

    The ground-state energy, hybridization matrix element, local moment, and spin-density correlations of a one-dimensional, finite-chain, periodic, symmetric Anderson model are obtained by numerical simulations and compared with perturbation theory and strong-coupling results. It is found that the local f-electron spins are compensated by correlation with other f-electrons as well as band electrons leading to a nonmagnetic ground state.

  13. Perturbative Interpretation of Adaptive Thouless-Anderson-Palmer Free Energy

    NASA Astrophysics Data System (ADS)

    Yasuda, Muneki; Takahashi, Chako; Tanaka, Kazuyuki

    2016-07-01

    In conventional well-known derivation methods for the adaptive Thouless-Anderson-Palmer (TAP) free energy, special assumptions that are difficult to mathematically justify except in some mean-field models, must be made. Here, we present a new adaptive TAP free energy derivation method. Using this derivation technique, without any special assumptions, the adaptive TAP free energy can be simply obtained as a high-temperature expansion of the Gibbs free energy.

  14. Solar hot water system installed at Anderson, South Carolina

    NASA Technical Reports Server (NTRS)

    1978-01-01

    A description is given of the solar energy hot water system installed in the Days Inns of America, Inc., at Anderson, South Carolina. The building is a low-rise, two-story 114-room motel. The solar system was designed to provide 40 percent of the total hot water demand. The collector is a flat plate, liquid with an area of 750 square feet. Operation of this system was begun in November 1977, and has performed flawlessly for one year.

  15. Many-body Anderson localization in one-dimensional systems

    NASA Astrophysics Data System (ADS)

    Delande, Dominique; Sacha, Krzysztof; Płodzień, Marcin; Avazbaev, Sanat K.; Zakrzewski, Jakub

    2013-04-01

    We show, using quasi-exact numerical simulations, that Anderson localization in a disordered one-dimensional potential survives in the presence of attractive interaction between particles. The localization length of the particles' center of mass—computed analytically for weak disorder—is in good agreement with the quasi-exact numerical observations using the time evolving block decimation algorithm. Our approach allows for simulation of the entire experiment including the final measurement of all atom positions.

  16. Markovian Anderson Model: Bounds for the Rate of Propagation

    NASA Astrophysics Data System (ADS)

    Tcheremchantsev, Serguei

    We consider the Anderson model in with potentials whose values at any site of the lattice are Markovian independent random functions of time. For solutions to the time-dependent Schrödinger equation we show under some conditions that with probability 1 where for d=1,2 and for .

  17. Quantum phase transitions in the pseudogap Anderson Holstein model

    NASA Astrophysics Data System (ADS)

    Cheng, Mengxing; Ingersent, Kevin

    2011-03-01

    We study a pseudogap Anderson-Holstein model of a magnetic impurity level that (1) hybridizes with a conduction band whose density of states vanishes in power-law fashion at the Fermi energy, and (2) couples, via its charge, to a nondispersive bosonic mode (e.g., an optical phonon). The model exhibits quantum phase transitions (QPTs) of different types depending on the strength λ of the impurity-boson coupling. For small λ , the suppression of the density of states near the Fermi energy leads to QPTs between strong-coupling (Kondo) and local-moment phases. A sufficiently large λ , however, transforms the bare Coulomb repulsion between a pair of electrons in the impurity level into an effective attraction, leading to QPTs between strong-coupling (charge-Kondo) and local-charge phases. Critical exponents characterizing the response to a local magnetic field (for small λ) or electric potential (for large λ) suggest that the QPTs belong to the same universality class as the QPT of the previously studied pseudogap Anderson model. One specific case of the pseudogap Anderson-Holstein model may be realized in a double-quantum-dot device, where the QPTs manifest themselves in the finite- temperature linear electrical conductance. Supported by NSF grant DMR-0710540.

  18. A Suitable Option for Gustilo and Anderson Grade III Injury

    PubMed Central

    Yang, Ronghua; Wang, Zhijun; Huang, Wenzhu; Zhao, Yuhuan; Xu, Lusheng; Yu, Shaobin

    2016-01-01

    Background The management of Gustilo and Anderson grade III injury remains difficult, particularly due to the incidence of wound infections, delayed fracture union, and traumatic extremity amputation. However, little data is available on delayed skin graft or flap reconstructions of Gustilo grade III injury, especially using new technologies of wound coverage, such as vacuum sealing drainage (VSD) combined with limited internal and/or external fixation. Material/Methods Between June 2008 and May 2013, we performed the VSD technique combined with limited internal and/or external fixation on 38 patients (22 males and 16 females, with a mean age of 36.5 years) with Gustilo and Anderson grade III injury. VSD was regularly changed and delayed skin grafts or flaps were used to cover the defect. Two patients were lost to follow-up, and the remaining 36 were available for evaluation. The complications, wound healing, infections, and bony union were assessed for a mean duration of 2.5 years (range, 1–4 years). Results Complications were seen in 5 of the 36 cases: 2 cases had infection alone, 1 case had delayed union or nonunion, 1 case had infection and delayed union, and 1 case had wound necrosis, infection, and nonunion. VSD was regularly changed 2–6 times. Morphological appearance and functional recovery were satisfactory in all cases. Conclusions Using VSD before skin grafts or flaps coverage, combined with limited internal and/or external fixation, is a suitable option for Gustilo and Anderson grade III injury. PMID:27564219

  19. Topological Anderson insulator induced by inter-cell hopping disorder

    SciTech Connect

    Lv, Shu-Hui; Song, Juntao Li, Yu-Xian

    2013-11-14

    We have studied in detail the influence of same-orbit and different-orbit hopping disorders in HgTe/CdTe quantum wells. Intriguingly, similar to the behavior of the on-site Anderson disorder, a phase transition from a topologically trivial phase to a topological phase is induced at a proper strength of the same-orbit hopping disorder. For different-orbit hopping disorder, however, the phase transition does not occur. The results have been analytically verified by using effective medium theory. A consistent conclusion can be obtained by comparing phase diagrams, conductance, and conductance fluctuations. In addition, the influence of Rashba spin-orbit interaction (RSOI) on the system has been studied for different types of disorder, and the RSOI shows different influence on topological phase at different disorders. The topological phase induced by same-orbit hopping disorder is more robust against the RSOI than that induced by on-site Anderson disorder. For different-orbit hopping disorder, no matter whether the RSOI is included or not, the phase transition does not occur. The results indicate, whether or not the topological Anderson insulator can be observed depends on a competition between the different types of the disorder as well as the strength of the RSOI in a system.

  20. A Suitable Option for Gustilo and Anderson Grade III Injury.

    PubMed

    Yang, Ronghua; Wang, Zhijun; Huang, Wenzhu; Zhao, Yuhuan; Xu, Lusheng; Yu, Shaobin

    2016-01-01

    BACKGROUND The management of Gustilo and Anderson grade III injury remains difficult, particularly due to the incidence of wound infections, delayed fracture union, and traumatic extremity amputation. However, little data is available on delayed skin graft or flap reconstructions of Gustilo grade III injury, especially using new technologies of wound coverage, such as vacuum sealing drainage (VSD) combined with limited internal and/or external fixation. MATERIAL AND METHODS Between June 2008 and May 2013, we performed the VSD technique combined with limited internal and/or external fixation on 38 patients (22 males and 16 females, with a mean age of 36.5 years) with Gustilo and Anderson grade III injury. VSD was regularly changed and delayed skin grafts or flaps were used to cover the defect. Two patients were lost to follow-up, and the remaining 36 were available for evaluation. The complications, wound healing, infections, and bony union were assessed for a mean duration of 2.5 years (range, 1-4 years). RESULTS Complications were seen in 5 of the 36 cases: 2 cases had infection alone, 1 case had delayed union or nonunion, 1 case had infection and delayed union, and 1 case had wound necrosis, infection, and nonunion. VSD was regularly changed 2-6 times. Morphological appearance and functional recovery were satisfactory in all cases. CONCLUSIONS Using VSD before skin grafts or flaps coverage, combined with limited internal and/or external fixation, is a suitable option for Gustilo and Anderson grade III injury. PMID:27564219

  1. On the Anderson localization conjecture in Dusty Plasma

    NASA Astrophysics Data System (ADS)

    Liaw, Constanze; Busse, Kyle; Matthews, Lorin; Hyde, Truell

    2015-11-01

    In 1958, Anderson suggested that sufficiently large impurities in a semi-conductor could lead to spatial localization of electrons. This idea unfolded into the field of Anderson Localization, one of the most fascinating phenomena in solid-state physics as it plays a major role in the conductive properties of imperfectly ordered materials. The Anderson Localization Conjecture claims that random disorder of any strength causes localization of electrons in the medium. The problem has proven to be highly non-trivial. Over the years the community has argued whether spatial localization occurs in 2D for small impurities. From a mathematical standpoint, the conjecture is still considered an open question. In 2013, Liaw challenged the commonly held assumption that localization holds in 2D by introducing a new mathematically more rigorous method to test for extended states, and applying it to the discrete random Schrödinger operator. One of the advantages of the underlying method is its versatility. It can be applied to any ordered system such as colloids, crystals, and atomic lattices. In a cross-disciplinary effort we merge this method with a numerical code used to simulate 2D physics systems, in preparation for experimentally testing the theory against complex plasma crystals.

  2. Note: Work function change measurement via improved Anderson method

    SciTech Connect

    Sabik, A. Gołek, F.; Antczak, G.

    2015-05-15

    We propose the modification to the Anderson method of work function change (Δϕ) measurements. In this technique, the kinetic energy of the probing electrons is already low enough for non-destructive investigation of delicate molecular systems. However, in our implementation, all electrodes including filament of the electron gun are polarized positively. As a consequence, electron bombardment of any elements of experimental system is eliminated. Our modification improves cleanliness of the ultra-high vacuum system. As an illustration of the solution capabilities, we present Δϕ of the Ag(100) surface induced by cobalt phthalocyanine layers.

  3. Transversal Anderson localization of sound in acoustic waveguide arrays.

    PubMed

    Ye, Yangtao; Ke, Manzhu; Feng, Junheng; Wang, Mudi; Qiu, Chunyin; Liu, Zhengyou

    2015-04-22

    We present designs of one-dimensional acoustic waveguide arrays and investigate wave propagation inside. Under the condition of single identical waveguide mode and weak coupling, the acoustic wave motion in waveguide arrays can be modeled with a discrete mode-coupling theory. The coupling constants can be retrieved from simulations or experiments as the function of neighboring waveguide separations. Sound injected into periodic arrays gives rise to the discrete diffraction, exhibiting ballistic or extended transport in transversal direction. But sound injected into randomized waveguide arrays readily leads to Anderson localization transversally. The experimental results show good agreement with simulations and theoretical predictions. PMID:25812602

  4. STS-118 Astronauts Rick Mastracchio and Clay Anderson Perform EVA

    NASA Technical Reports Server (NTRS)

    2007-01-01

    As the construction continued on the International Space Station (ISS), STS-118 astronaut and mission specialist Rick Mastracchio was anchored on the foot restraint of the Canadarm2 as he participated in the third session of Extra Vehicular Activity (EVA) for the mission. Assisting Mastracchio was Expedition 15 flight engineer Clay Anderson (out of frame). During the 5 hour, 28 minute space walk, the two relocated the S-band Antenna Sub-Assembly from the Port 6 (P6) truss to the Port 1 (P1) truss, installed a new transponder on P1 and retrieved the P6 transponder.

  5. Note: Work function change measurement via improved Anderson method.

    PubMed

    Sabik, A; Gołek, F; Antczak, G

    2015-05-01

    We propose the modification to the Anderson method of work function change (Δϕ) measurements. In this technique, the kinetic energy of the probing electrons is already low enough for non-destructive investigation of delicate molecular systems. However, in our implementation, all electrodes including filament of the electron gun are polarized positively. As a consequence, electron bombardment of any elements of experimental system is eliminated. Our modification improves cleanliness of the ultra-high vacuum system. As an illustration of the solution capabilities, we present Δϕ of the Ag(100) surface induced by cobalt phthalocyanine layers. PMID:26026572

  6. Remembering Joan (Jan) Mary Anderson (1932-2015).

    PubMed

    Chow, Wah Soon; Horton, Peter; Barrett, Martin; Osmond, Charles Barry

    2016-08-01

    Joan Mary Anderson, known to most people as Jan, was born on May 12, 1932 in Dunedin, New Zealand. She died on August 28, 2015 in Canberra, Australia. To celebrate her life, we present here a brief biography, some comments on her discoveries in photosynthesis during a career spanning more than half a century, and reminiscences from family and friends. We remember this wonderful person who had an unflagging curiosity, creative ability to think laterally, enthusiasm, passion, generosity and love of color and culture. PMID:27363420

  7. Quasiperiodic driving of Anderson localized waves in one dimension

    NASA Astrophysics Data System (ADS)

    Hatami, H.; Danieli, C.; Bodyfelt, J. D.; Flach, S.

    2016-06-01

    We consider a quantum particle in a one-dimensional disordered lattice with Anderson localization in the presence of multifrequency perturbations of the onsite energies. Using the Floquet representation, we transform the eigenvalue problem into a Wannier-Stark basis. Each frequency component contributes either to a single channel or a multichannel connectivity along the lattice, depending on the control parameters. The single-channel regime is essentially equivalent to the undriven case. The multichannel driving increases substantially the localization length for slow driving, showing two different scaling regimes of weak and strong driving, yet the localization length stays finite for a finite number of frequency components.

  8. The S=1 Underscreened Anderson Lattice model for Uranium compounds

    NASA Astrophysics Data System (ADS)

    Thomas, C.; Simões, A. S. R.; Iglesias, J. R.; Lacroix, C.; Perkins, N. B.; Coqblin, B.

    2011-01-01

    Magnetic properties of uranium and neptunium compounds showing coexistence of the Kondo effect and ferromagnetic order are investigated within the degenerate Anderson Lattice Hamiltonian, describing a 5f2 electronic configuration with S = 1 spins. Through the Schrieffer-Wolff transformation, both an exchange Kondo interaction for the S = 1 f-spins and an effective f-band term are obtained, allowing to describe the coexistence of Kondo effect and ferromagnetic ordering and a weak delocalization of the 5f-electrons. We calculate the Kondo and Curie temperatures and we can account for the pressure dependence of the Curie temperature of UTe.

  9. Collective Kondo effect in the Anderson-Hubbard lattice

    NASA Astrophysics Data System (ADS)

    Fazekas, P.; Itai, K.

    1997-02-01

    The periodic Anderson model is extended by switching on a Hubbard U for the conduction electrons. We use the Gutzwiller variational method to study the nearly integral valent limit. The lattice Kondo energy contains the U-dependent chemical potential of the Hubbard subsystem in the exponent, and the correlation-induced band narrowing in the prefactor. Both effects tend to suppress the Kondo scale, which can be understood to result from the blocking of hybridization. At half-filling, we find a Brinkman-Rice-type transition from a Kondo insulator to a Mott insulator.

  10. Theory of the Anderson transition in the quasiperiodic kicked rotor.

    PubMed

    Tian, Chushun; Altland, Alexander; Garst, Markus

    2011-08-12

    We present the first microscopic theory of transport in quasiperiodically driven environments ("kicked rotors"), as realized in recent atom optic experiments. We find that the behavior of these systems depends sensitively on the value of a dimensionless Planck constant h: for irrational values of h/(4π) they fall into the universality class of disordered electronic systems and we describe the corresponding localization phenomena. In contrast, for rational values the rotor-Anderson insulator acquires an infinite (static) conductivity and turns into a "supermetal." We discuss the ensuing possibility of a metal-supermetal quantum phase transition. PMID:21902396

  11. Kubo-Anderson Mixing in the Turbulent Boundary Layer

    NASA Astrophysics Data System (ADS)

    Dekker, H.; de Leeuw, G.; Brink, A. Maassen Van Den

    A novel ab initio analysis of the Reynolds stress is presented in order to model non-local turbulence transport. The theory involves a sample path space and a stochastic hypothesis. A scaling relation maps the path space onto the boundary layer. Analytical sampling rates are shown to model mixing by exchange. Nonlocal mixing involves a scaling exponent ɛ≈0.58 (ɛ→∞ in the diffusion limit). The resulting transport equation represents a nondiffusive (Kubo-Anderson or kangaroo) type stochastic process.

  12. Experimental Observation of Two-Dimensional Anderson Localization with the Atomic Kicked Rotor.

    PubMed

    Manai, Isam; Clément, Jean-François; Chicireanu, Radu; Hainaut, Clément; Garreau, Jean Claude; Szriftgiser, Pascal; Delande, Dominique

    2015-12-11

    Dimension 2 is expected to be the lower critical dimension for Anderson localization in a time-reversal-invariant disordered quantum system. Using an atomic quasiperiodic kicked rotor-equivalent to a two-dimensional Anderson-like model-we experimentally study Anderson localization in dimension 2 and we observe localized wave function dynamics. We also show that the localization length depends exponentially on the disorder strength and anisotropy and is in quantitative agreement with the predictions of the self-consistent theory for the 2D Anderson localization. PMID:26705619

  13. Anderson localization and Mott insulator phase in the time domain

    PubMed Central

    Sacha, Krzysztof

    2015-01-01

    Particles in space periodic potentials constitute standard models for investigation of crystalline phenomena in solid state physics. Time periodicity of periodically driven systems is a close analogue of space periodicity of solid state crystals. There is an intriguing question if solid state phenomena can be observed in the time domain. Here we show that wave-packets localized on resonant classical trajectories of periodically driven systems are ideal elements to realize Anderson localization or Mott insulator phase in the time domain. Uniform superpositions of the wave-packets form stationary states of a periodically driven particle. However, an additional perturbation that fluctuates in time results in disorder in time and Anderson localization effects emerge. Switching to many-particle systems we observe that depending on how strong particle interactions are, stationary states can be Bose-Einstein condensates or single Fock states where definite numbers of particles occupy the periodically evolving wave-packets. Our study shows that non-trivial crystal-like phenomena can be observed in the time domain. PMID:26074169

  14. Integrals of motion for one-dimensional Anderson localized systems

    NASA Astrophysics Data System (ADS)

    Modak, Ranjan; Mukerjee, Subroto; Yuzbashyan, Emil A.; Shastry, B. Sriram

    2016-03-01

    Anderson localization is known to be inevitable in one-dimension for generic disordered models. Since localization leads to Poissonian energy level statistics, we ask if localized systems possess ‘additional’ integrals of motion as well, so as to enhance the analogy with quantum integrable systems. We answer this in the affirmative in the present work. We construct a set of nontrivial integrals of motion for Anderson localized models, in terms of the original creation and annihilation operators. These are found as a power series in the hopping parameter. The recently found Type-1 Hamiltonians, which are known to be quantum integrable in a precise sense, motivate our construction. We note that these models can be viewed as disordered electron models with infinite-range hopping, where a similar series truncates at the linear order. We show that despite the infinite range hopping, all states but one are localized. We also study the conservation laws for the disorder free Aubry-Andre model, where the states are either localized or extended, depending on the strength of a coupling constant. We formulate a specific procedure for averaging over disorder, in order to examine the convergence of the power series. Using this procedure in the Aubry-Andre model, we show that integrals of motion given by our construction are well-defined in localized phase, but not so in the extended phase. Finally, we also obtain the integrals of motion for a model with interactions to lowest order in the interaction.

  15. Phase Boundaries of the Pseudogap Anderson Impurity Model

    NASA Astrophysics Data System (ADS)

    Mohammed, Aaron; Chowdhury, Tathagata; Ingersent, Kevin

    2015-03-01

    As the temperature of metals containing dilute concentrations of magnetic impurities reach very low temperatures, a phenomenon known as the Kondo effect takes place in which the resistance increases. This is due to the domination of spin-exchange processes that occur between the electrons of the metal and the electrons of the magnetic impurity near absolute zero. The Anderson model is a quantum impurity model that was developed in the 1960s to explain this phenomenon. It involves a single magnetic impurity tunnel-coupled to the conduction band of a metal. If the conduction band of this system contains a pseudogap, or a power-law decrease in the density of states around the Fermi energy, then quantum phase transitions will occur. The phase boundaries of the pseudogap Anderson impurity model have been previously approximated using poor man's scaling analysis. Here, we focus on using the more accurate numerical renormalization group method to calculate the location of these boundaries. We then compare these numerical results with the predictions derived from the scaling approximations. The development of nanotechnology like quantum dots and STM have rekindled interest in the Kondo effect since it can now be studied within controlled settings. Supported by the NSF REU Grant DMR-1156737: REU Site in Materials Physics at the University of Florida.

  16. Reply. [to the comment by Anderson et al. (1993)

    NASA Technical Reports Server (NTRS)

    Hegg, Dean A.; Ferek, Ronald G.; Hobbs, Peter V.

    1994-01-01

    While Hegg et al. (1993) accepts the criticism of Anderson et al. (1994) in principle, this involves the adoption of an aerosol composition model and the model that they propose to reconcile these observations with the assertion of Charlson et al. (1992) does not agree with many observations, particularly those made over the North Atlantic Ocean. Although the use of a gain factor (i.e. the partial derivative of aerosol mass with respect to the sulfate ion), proposed by Anderson et al., may be valid for particular cases where a proposed composition model really reflects the actual aerosol composition, this procedure is considered questionable in general. The use of sulfate as a tracer for nonsulfate aerosol mass is questionable, because in the present authors' data set, sulfate averaged only about 26% of the dry aerosol mass. The ammonium mass associated with sulfate mass is not analogous to that betwen the oxygen mass and sulfur mass in the sulfate ion. Strong chemical bonds are present between sulfur and oxygen in sulfate, whereas ammonium and sulfate in haze droplets are ions in solution that may or may not be associated with one another. Thus, there is no reason to assume that sulfate will act as a reliable tracer of ammonium mass. Hegg et al. expresses the view that their approach used for estimating sulfate light scattering efficiency is appropriate for the current level of understanding of atmospheric aerosols.

  17. Ferromagnetism in the two-dimensional periodic Anderson model

    SciTech Connect

    Batista, C. D.; Bonca, J.; Gubernatis, J. E.

    2001-05-01

    Using the constrained-path Monte Carlo method, we studied the magnetic properties of the two-dimensional periodic Anderson model for electron fillings between 1/4 and 1/2. We also derived two effective low-energy theories to assist in interpreting the numerical results. For 1/4 filling, we found that the system can be a Mott or a charge-transfer insulator, depending on the relative values of the Coulomb interaction and the charge-transfer gap between the two noninteracting bands. The insulator may be a paramagnet or antiferromagnet. We concentrated on the effect of electron doping on these insulating phases. Upon doping we obtained a partially saturated ferromagnetic phase for low concentrations of conduction electrons. If the system were a charge-transfer insulator, we would find that the ferromagnetism is induced by the well-known Ruderman-Kittel-Kasuya-Yosida interaction. However, we found a novel correlated hopping mechanism inducing the ferromagnetism in the region where the nondoped system is a Mott insulator. Our regions of ferromagnetism spanned a much smaller doping range than suggested by recent slave boson and dynamical mean-field theory calculations, but they were consistent with that obtained by density-matrix renormalization group calculations of the one-dimensional periodic Anderson model.

  18. Anderson localization and Mott insulator phase in the time domain.

    PubMed

    Sacha, Krzysztof

    2015-01-01

    Particles in space periodic potentials constitute standard models for investigation of crystalline phenomena in solid state physics. Time periodicity of periodically driven systems is a close analogue of space periodicity of solid state crystals. There is an intriguing question if solid state phenomena can be observed in the time domain. Here we show that wave-packets localized on resonant classical trajectories of periodically driven systems are ideal elements to realize Anderson localization or Mott insulator phase in the time domain. Uniform superpositions of the wave-packets form stationary states of a periodically driven particle. However, an additional perturbation that fluctuates in time results in disorder in time and Anderson localization effects emerge. Switching to many-particle systems we observe that depending on how strong particle interactions are, stationary states can be Bose-Einstein condensates or single Fock states where definite numbers of particles occupy the periodically evolving wave-packets. Our study shows that non-trivial crystal-like phenomena can be observed in the time domain. PMID:26074169

  19. La place de la double arthrodèse dans la prise en charge du pied bot varus équin invétéré

    PubMed Central

    Atarraf, Karima; Arroud, Mounir; Chater, Lamiae; Afifi, My Abderrahmane

    2014-01-01

    La prise en charge du pied bot varus équin invétéré ( PBVEI) pose d’énormes problèmes thérapeutiques. La double arthrodèse sous-talienne et médio-tarsienne longtemps considérée comme la solution de sécurité pour ces déformations est encore couramment utilisée. Nous rapportons une série de 13 enfants opérés pour un pied bot varus équin invétérés (16 pieds) par Arthrodèse sous-talienne et médio tarsienne réalisée au service d'orthopédie pédiatrique du CHU Hassan II; de Fès au Maroc sur une période de 4 ans; étalée de janvier 2009 à décembre 2012. L’âge moyen de nos patients était de 12,6 ans avec prédominance féminine. L'origine congénitale était retrouvée chez 10 patients. L'atteinte était gauche chez 8 patients avec une localisation bilatérale chez 3 patients. La radiographie standard du pied de face et de profil a révélée une divergence talo-calcanéenne qui variait entre 5 et 20°, l'angle talus-1er métatarsien entre 20 et 40° (avec une moyenne de 28°) et l'angle calcanéus-5ème métatarsien entre 15° et 45° (avec une moyenne de 30°). Tous les patients ont bénéficiés d'une arthrodèse sous-talienne et médio tarsienne. Les résultats étaient satisfaisants dans 98% des cas. Le pied était plantigrade dans 9 cas, le varus de l'arrière pied persistait dans 4 pieds alors que l’équin et le varus de l'avant pied étaient notés chez 2 cas. La double arthrodèse est l'intervention idéale pour stabiliser et corriger les déformations rencontrées dans le PBVE invétéré, elle assure totalement le verrouillage du couple de torsion. Elle permet outre une correction des diverses déformations et une ré-axation de l'arrière-pied dans les 3 plans de l'espace. PMID:25829977

  20. 75 FR 34170 - Plastic Omnium Automotive Exteriors, LLC, Anderson, SC; Plastic Omnium Automotive Exteriors, LLC...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-16

    ... Assistance on March 18, 2010, applicable to workers of Plastic Omnium Automotive Exteriors, LLC, Anderson, South Carolina. The notice was published in the Federal Register April 23, 2010 (75 FR 21356). The... Employment and Training Administration Plastic Omnium Automotive Exteriors, LLC, Anderson, SC; Plastic...

  1. How Large is Large? Estimating the Critical Disorder for the Anderson Model

    NASA Astrophysics Data System (ADS)

    Schenker, Jeffrey

    2015-01-01

    Complete localization is shown to hold for the d-dimensional Anderson model with uniformly distributed random potentials provided the disorder strength where satisfies with the self-avoiding walk connective constant for the lattice . Notably, is precisely the large disorder threshold proposed by Anderson in 1958.

  2. The topological Anderson insulator phase in the Kane-Mele model

    PubMed Central

    Orth, Christoph P.; Sekera, Tibor; Bruder, Christoph; Schmidt, Thomas L.

    2016-01-01

    It has been proposed that adding disorder to a topologically trivial mercury telluride/cadmium telluride (HgTe/CdTe) quantum well can induce a transition to a topologically nontrivial state. The resulting state was termed topological Anderson insulator and was found in computer simulations of the Bernevig-Hughes-Zhang model. Here, we show that the topological Anderson insulator is a more universal phenomenon and also appears in the Kane-Mele model of topological insulators on a honeycomb lattice. We numerically investigate the interplay of the relevant parameters, and establish the parameter range in which the topological Anderson insulator exists. A staggered sublattice potential turns out to be a necessary condition for the transition to the topological Anderson insulator. For weak enough disorder, a calculation based on the lowest-order Born approximation reproduces quantitatively the numerical data. Our results thus considerably increase the number of candidate materials for the topological Anderson insulator phase. PMID:27045779

  3. The topological Anderson insulator phase in the Kane-Mele model.

    PubMed

    Orth, Christoph P; Sekera, Tibor; Bruder, Christoph; Schmidt, Thomas L

    2016-01-01

    It has been proposed that adding disorder to a topologically trivial mercury telluride/cadmium telluride (HgTe/CdTe) quantum well can induce a transition to a topologically nontrivial state. The resulting state was termed topological Anderson insulator and was found in computer simulations of the Bernevig-Hughes-Zhang model. Here, we show that the topological Anderson insulator is a more universal phenomenon and also appears in the Kane-Mele model of topological insulators on a honeycomb lattice. We numerically investigate the interplay of the relevant parameters, and establish the parameter range in which the topological Anderson insulator exists. A staggered sublattice potential turns out to be a necessary condition for the transition to the topological Anderson insulator. For weak enough disorder, a calculation based on the lowest-order Born approximation reproduces quantitatively the numerical data. Our results thus considerably increase the number of candidate materials for the topological Anderson insulator phase. PMID:27045779

  4. The topological Anderson insulator phase in the Kane-Mele model

    NASA Astrophysics Data System (ADS)

    Orth, Christoph P.; Sekera, Tibor; Bruder, Christoph; Schmidt, Thomas L.

    2016-04-01

    It has been proposed that adding disorder to a topologically trivial mercury telluride/cadmium telluride (HgTe/CdTe) quantum well can induce a transition to a topologically nontrivial state. The resulting state was termed topological Anderson insulator and was found in computer simulations of the Bernevig-Hughes-Zhang model. Here, we show that the topological Anderson insulator is a more universal phenomenon and also appears in the Kane-Mele model of topological insulators on a honeycomb lattice. We numerically investigate the interplay of the relevant parameters, and establish the parameter range in which the topological Anderson insulator exists. A staggered sublattice potential turns out to be a necessary condition for the transition to the topological Anderson insulator. For weak enough disorder, a calculation based on the lowest-order Born approximation reproduces quantitatively the numerical data. Our results thus considerably increase the number of candidate materials for the topological Anderson insulator phase.

  5. 78 FR 11626 - Foreign-Trade Zone 176-Rockford, IL, Authorization of Production Activity, AndersonBrecon Inc...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-19

    ..., AndersonBrecon Inc. (Medical Device Kitting), Rockford, IL On October 12, 2012, AndersonBrecon Inc... public comment (77 FR 64311, 10-19-2012). The FTZ Board has determined that no further review of...

  6. Anderson Localization, Non-linearity and Stable Genetic Diversity

    NASA Astrophysics Data System (ADS)

    Epstein, Charles L.

    2006-07-01

    In many models of genotypic evolution, the vector of genotype populations satisfies a system of linear ordinary differential equations. This system of equations models a competition between differential replication rates (fitness) and mutation. Mutation operates as a generalized diffusion process on genotype space. In the large time asymptotics, the replication term tends to produce a single dominant quasi-species, unless the mutation rate is too high, in which case the asymptotic population becomes de-localized. We introduce a more macroscopic picture of genotypic evolution wherein a random fitness term in the linear model produces features analogous to Anderson localization. When coupled with density dependent non-linearities, which limit the population of any given genotype, we obtain a model whose large time asymptotics display stable genotypic diversity.

  7. [Fabry-Anderson disease: current state of knowledge].

    PubMed

    Vega-Vega, Olynka; Pérez-Gutiérrez, Angélica; Correa-Rotter, Ricardo

    2011-01-01

    Fabry-Anderson disease is a lysosomal storage disease caused by deficiency of the enzyme alpha-galactosidase. This enzymatic defect results in the accumulation of glycosphingolipid into different lines cells. Usually the deficiency is complete, resulting in a multisystem disorder, with injury in different organs, predominantly heart, kidney and nervous system. However, in some patients the enzymatic deficit is partial and causes diverse clinical variants of the disease (renal or cardiac variety), this cause a difficult diagnostic and the absence of real epidemiology data. This review is about the epidemiology, the metabolic defect of this disease, it's molecular and genetics bases, the different forms of clinical presentation and the enzyme replacement therapy. PMID:21888295

  8. Universal Knight shift anomaly in the periodic Anderson model

    NASA Astrophysics Data System (ADS)

    Jiang, M.; Curro, N. J.; Scalettar, R. T.

    2014-12-01

    We report a determinant Quantum Monte Carlo investigation which quantifies the behavior of the susceptibility and the entropy in the framework of the periodic Anderson model, focusing on the evolution with different degree of conduction electron (c )-local moment (f ) hybridization. These results capture the behavior observed in several experiments, including the universal behavior of the NMR Knight shift anomaly below the crossover temperature T*. We find that T* is a measure of the onset of c - f correlations and grows with increasing hybridization. These results suggest that the NMR Knight shift and spin-lattice relaxation rate measurements in non-Fermi-liquid materials are strongly influenced by the temperature dependence of the c - f kinetic energy. Our results provide a microscopic basis for the phenomenological two-fluid model of Kondo lattice behavior, and its evolution with pressure and temperature.

  9. Topological Anderson insulators in systems without time-reversal symmetry

    NASA Astrophysics Data System (ADS)

    Su, Ying; Avishai, Y.; Wang, X. R.

    2016-06-01

    Occurrence of the topological Anderson insulator (TAI) in a HgTe quantum well suggests that when time-reversal symmetry (TRS) is maintained, the pertinent topological phase transition, marked by re-entrant 2 e2/h quantized conductance contributed by helical edge states, is driven by disorder. Here we show that when TRS is broken, the physics of the TAI becomes even richer. The pattern of longitudinal conductance and nonequilibrium local current distribution displays novel TAI phases characterized by nonzero Chern numbers, indicating the occurrence of multiple chiral edge modes. Tuning either disorder or Fermi energy (in both topologically trivial and nontrivial phases), drives transitions between these distinct TAI phases, characterized by jumps of the quantized conductance from 0 to e2/h and from e2/h to 2 e2/h . An effective medium theory based on the Born approximation yields an accurate description of different TAI phases in parameter space.

  10. Limb salvage talectomy for 3C Gustilo–Anderson fracture

    PubMed Central

    Mohammad, Hasan Raza; Pillai, Anand

    2016-01-01

    Foot fractures vary in severity with complex midfoot fractures having poor morbidity rates and high amputation rates. Complex midfoot fractures are rarely reported since they are uncommon and only treated in specialist centres. Given the important role of the midfoot in foot function, reconstruction is preferable. Soft tissue management on the dorsal aspect of the foot poses further challenges to reconstructive surgeons. We report a case of a 55-year-old woman who sustained an open 3C Gustilo–Anderson fracture that was initially treated with open reduction internal fixation and free flap. She subsequently developed flap and internal fixation failure with osteomyelitis of the talus. We report a good outcome using primary limb shortening with a talectomy, tibiocalcaneal arthrodesis using external fixation and a combination of vancomycin-loaded calcium sulphate and intravenous antibiotics in our patient. PMID:27173882

  11. Atomic Bose and Anderson Glasses in Optical Lattices

    NASA Astrophysics Data System (ADS)

    Damski, B.; Zakrzewski, J.; Santos, L.; Zoller, P.; Lewenstein, M.

    2003-08-01

    An ultracold atomic Bose gas in an optical lattice is shown to provide an ideal system for the controlled analysis of disordered Bose lattice gases. This goal may be easily achieved under the current experimental conditions by introducing a pseudorandom potential created by a second additional lattice or, alternatively, by placing a speckle pattern on the main lattice. We show that, for a noncommensurable filling factor, in the strong-interaction limit, a controlled growing of the disorder drives a dynamical transition from superfluid to Bose-glass phase. Similarly, in the weak interaction limit, a dynamical transition from superfluid to Anderson-glass phase may be observed. In both regimes, we show that even very low-intensity disorder-inducing lasers cause large modifications of the superfluid fraction of the system.

  12. Multi-Scale Jacobi Method for Anderson Localization

    NASA Astrophysics Data System (ADS)

    Imbrie, John Z.

    2015-11-01

    A new KAM-style proof of Anderson localization is obtained. A sequence of local rotations is defined, such that off-diagonal matrix elements of the Hamiltonian are driven rapidly to zero. This leads to the first proof via multi-scale analysis of exponential decay of the eigenfunction correlator (this implies strong dynamical localization). The method has been used in recent work on many-body localization (Imbrie in On many-body localization for quantum spin chains, arXiv:1403.7837 , 2014).

  13. Bosonic Josephson effect in the Fano-Anderson model

    NASA Astrophysics Data System (ADS)

    Engelhardt, G.; Schaller, G.; Brandes, T.

    2016-07-01

    We investigate the coherent dynamics of a noninteracting Bose-Einstein condensate in a system consisting of two bosonic reservoirs coupled via a spatially localized mode. We describe this system by a two-terminal Fano-Anderson model and investigate analytically the time evolution of observables such as the Josephson current. In doing so, we find that the Josephson current sensitively depends on the on-site energy of the localized mode. This facilitates using this setup as a transistor for a Bose-Einstein condensate. We identify two regimes. In one regime, the system exhibits well-behaved long-time dynamics with a slowly oscillating and undamped Josephson current. In a second regime, the Josephson current is a superposition of an extremely weakly damped slow oscillation and an undamped fast oscillation. Our results are confirmed by finite-size simulations.

  14. Measurement of the mobility edge for 3D Anderson localization

    NASA Astrophysics Data System (ADS)

    Semeghini, Giulia; Landini, Manuele; Castilho, Patricia; Roy, Sanjukta; Spagnolli, Giacomo; Trenkwalder, Andreas; Fattori, Marco; Inguscio, Massimo; Modugno, Giovanni

    2016-05-01

    An outstanding problem of Anderson localization (AL) in 3D systems is the determination of the mobility edge, i.e. the energy threshold that separates localized and extended states. In our experiment we use a Bose-Einstein condensate of 39 K atoms and study its transport properties in a disordered optical potential. By tuning the inter-particle interactions to zero via magnetic Feshbach resonances, we study the single-particle phenomenon of AL. A novel technique to measure and control the atomic energy distribution allows us to measure for the first time the position of the localization threshold as a function of the disorder strength. We also study how the addition of finite repulsive or attractive interactions breaks the localized regime and triggers subdiffusive expansion of the atoms. In the future, similar experiments might also probe the existence of many-body localization in 3D.

  15. Two-impurity Anderson model: A variational study

    SciTech Connect

    Andreani, L.C. , PHB-Ecublens, CH-1015 Lausanne Dipartimento di Fisica A. Volta,'' Universita di Pavia, via Bassi 6, I-27100 Pavia ); Beck, H. )

    1993-09-01

    A comprehensive variational study of the two-impurity Anderson model is presented. First a lowest-order basis is introduced, which does not contain electronic excitations above the Fermi level: in this basis, the indirect [ital f]-[ital f] interaction of the form [minus][ital J][bold S][sub 1][center dot][bold S][sub 2] is not generated but is added by hand. The effect of electron-hole (EH) excitations is also studied. A suitable discretization of the continuous band spectrum allows us to obtain all eigenvalues and eigenvectors and to calculate finite-temperature magnetic properties. For a distance [ital R][gt][ital R][sub [ital c

  16. Integrals of motion for one-dimensional Anderson localized systems

    DOE PAGESBeta

    Modak, Ranjan; Mukerjee, Subroto; Yuzbashyan, Emil A.; Shastry, B. Sriram

    2016-03-02

    Anderson localization is known to be inevitable in one-dimension for generic disordered models. Since localization leads to Poissonian energy level statistics, we ask if localized systems possess ‘additional’ integrals of motion as well, so as to enhance the analogy with quantum integrable systems. Weanswer this in the affirmative in the present work. We construct a set of nontrivial integrals of motion for Anderson localized models, in terms of the original creation and annihilation operators. These are found as a power series in the hopping parameter. The recently found Type-1 Hamiltonians, which are known to be quantum integrable in a precisemore » sense, motivate our construction.Wenote that these models can be viewed as disordered electron models with infinite-range hopping, where a similar series truncates at the linear order.Weshow that despite the infinite range hopping, all states but one are localized.Wealso study the conservation laws for the disorder free Aubry–Andre model, where the states are either localized or extended, depending on the strength of a coupling constant.Weformulate a specific procedure for averaging over disorder, in order to examine the convergence of the power series. Using this procedure in the Aubry–Andre model, we show that integrals of motion given by our construction are well-defined in localized phase, but not so in the extended phase. Lastly, we also obtain the integrals of motion for a model with interactions to lowest order in the interaction.« less

  17. Random Walks in Anderson's Garden: A Journey from Cuprates to Cooper Pair Insulators and Beyond

    NASA Astrophysics Data System (ADS)

    Baskaran, G.

    Anderson's Garden is a drawing presented to Philip W. Anderson on the eve of his 60th birthday celebration, in 1983, by a colleague (author unknown). This cartoon (Fig. 1) succinctly depicts some of Anderson's pre-1983 works. As an avid reader of Anderson's papers, a random walk in Anderson's garden had become a part of my routine since graduate school days. This was of immense help and prepared me for a wonderful collaboration with Anderson on the theory of high-Tc cuprates and quantum spin liquids at Princeton. Here I narrate this story, ending with a brief summary of my ongoing theoretical efforts to extend Anderson's RVB theory for superconductivity to encompass the recently observed high-temperature (Tc ~ 203K) superconductivity in solid H2S at pressure ~200GPa. In H2S molecule, four valence electrons form two saturated covalent bonds, H-S-H. These bond singlets are confined Cooper pairs close to chemical potential. Solid H2S is a Cooper pair insulator. Pressure changes the structure and not the number of valence electrons. Bond singlet pairing tendency continues and new S-S and H-H bonds are formed. S-S bonds are mostly saturated. However, hydrogen sublattice has unsaturated H-H bonds. It prepares ground for a RVB superconducting state.

  18. Transport and Anderson localization in disordered two-dimensional photonic lattices.

    PubMed

    Schwartz, Tal; Bartal, Guy; Fishman, Shmuel; Segev, Mordechai

    2007-03-01

    One of the most interesting phenomena in solid-state physics is Anderson localization, which predicts that an electron may become immobile when placed in a disordered lattice. The origin of localization is interference between multiple scatterings of the electron by random defects in the potential, altering the eigenmodes from being extended (Bloch waves) to exponentially localized. As a result, the material is transformed from a conductor to an insulator. Anderson's work dates back to 1958, yet strong localization has never been observed in atomic crystals, because localization occurs only if the potential (the periodic lattice and the fluctuations superimposed on it) is time-independent. However, in atomic crystals important deviations from the Anderson model always occur, because of thermally excited phonons and electron-electron interactions. Realizing that Anderson localization is a wave phenomenon relying on interference, these concepts were extended to optics. Indeed, both weak and strong localization effects were experimentally demonstrated, traditionally by studying the transmission properties of randomly distributed optical scatterers (typically suspensions or powders of dielectric materials). However, in these studies the potential was fully random, rather than being 'frozen' fluctuations on a periodic potential, as the Anderson model assumes. Here we report the experimental observation of Anderson localization in a perturbed periodic potential: the transverse localization of light caused by random fluctuations on a two-dimensional photonic lattice. We demonstrate how ballistic transport becomes diffusive in the presence of disorder, and that crossover to Anderson localization occurs at a higher level of disorder. Finally, we study how nonlinearities affect Anderson localization. As Anderson localization is a universal phenomenon, the ideas presented here could also be implemented in other systems (for example, matter waves), thereby making it feasible

  19. Some comments on Anderson and Pospahala's correction of bias in line transect sampling

    USGS Publications Warehouse

    Anderson, D.R.; Burnham, K.P.; Chain, B.R.

    1980-01-01

    ANDERSON and POSPAHALA (1970) investigated the estimation of wildlife population size using the belt or line transect sampling method and devised a correction for bias, thus leading to an estimator with interesting characteristics. This work was given a uniform mathematical framework in BURNHAM and ANDERSON (1976). In this paper we show that the ANDERSON-POSPAHALA estimator is optimal in the sense of being the (unique) best linear unbiased estimator within the class of estimators which are linear combinations of cell frequencies, provided certain assumptions are met.

  20. Routes Towards Anderson-Like Localization of Bose-Einstein Condensates in Disordered Optical Lattices

    NASA Astrophysics Data System (ADS)

    Schulte, T.; Drenkelforth, S.; Kruse, J.; Ertmer, W.; Arlt, J.; Sacha, K.; Zakrzewski, J.; Lewenstein, M.

    2005-10-01

    We investigate, both experimentally and theoretically, possible routes towards Anderson-like localization of Bose-Einstein condensates in disordered potentials. The dependence of this quantum interference effect on the nonlinear interactions and the shape of the disorder potential is investigated. Experiments with an optical lattice and a superimposed disordered potential reveal the lack of Anderson localization. A theoretical analysis shows that this absence is due to the large length scale of the disorder potential as well as its screening by the nonlinear interactions. Further analysis shows that incommensurable superlattices should allow for the observation of the crossover from the nonlinear screening regime to the Anderson localized case within realistic experimental parameters.

  1. Quantum criticality at the Anderson transition: A typical medium theory perspective

    NASA Astrophysics Data System (ADS)

    Mahmoudian, Samiyeh; Tang, Shao; Dobrosavljević, Vladimir

    2015-10-01

    We present a complete analytical and numerical solution of the typical medium theory (TMT) for the Anderson metal-insulator transition. This approach self-consistently calculates the typical amplitude of the electronic wave functions, thus representing the conceptually simplest order-parameter theory for the Anderson transition. We identify all possible universality classes for the critical behavior, which can be found within such a mean-field approach. This provides insights into how interaction-induced renormalizations of the disorder potential may produce qualitative modifications of the critical behavior. We also formulate a simplified description of the leading critical behavior, thus obtaining an effective Landau theory for Anderson localization.

  2. Two-photon Anderson localization in a disordered quadratic waveguide array

    NASA Astrophysics Data System (ADS)

    Bai, Y. F.; Xu, P.; Lu, L. L.; Zhong, M. L.; Zhu, S. N.

    2016-05-01

    We theoretically investigate two-photon Anderson localization in a χ (2) waveguide array with off-diagonal disorder. The nonlinear parametric down-conversion process would enhance both the single-photon and the two-photon Anderson localization. In the strong disorder regime, the two-photon position correlation exhibits a bunching distribution around the pumped waveguides, which is independent of pumping conditions and geometrical structures of waveguide arrays. Quadratic nonlinearity can be supplied as a new ingredient for Anderson localization. Also, our results pave the way for engineering quantum states through nonlinear quantum walks.

  3. Routes Towards Anderson-Like Localization of Bose-Einstein Condensates in Disordered Optical Lattices

    SciTech Connect

    Schulte, T.; Drenkelforth, S.; Kruse, J.; Ertmer, W.; Arlt, J.; Sacha, K.; Zakrzewski, J.; Lewenstein, M.

    2005-10-21

    We investigate, both experimentally and theoretically, possible routes towards Anderson-like localization of Bose-Einstein condensates in disordered potentials. The dependence of this quantum interference effect on the nonlinear interactions and the shape of the disorder potential is investigated. Experiments with an optical lattice and a superimposed disordered potential reveal the lack of Anderson localization. A theoretical analysis shows that this absence is due to the large length scale of the disorder potential as well as its screening by the nonlinear interactions. Further analysis shows that incommensurable superlattices should allow for the observation of the crossover from the nonlinear screening regime to the Anderson localized case within realistic experimental parameters.

  4. Melissa L. Anderson: APA/APAGS Award for Distinguished Graduate Student in Professional Psychology.

    PubMed

    2012-11-01

    Presents a short biography of the winner of the American Psychological Association/American Psychological Association of Graduate Students Award for Distinguished Graduate Student in Professional Psychology. The 2012 winner is Melissa L. Anderson for her ongoing commitment to understanding, treating, and preventing domestic violence in Deaf women and underserved populations in general. Anderson is passionate in her efforts to study the factors underlying violence toward women and in applying psychological science to intervene in and prevent such abuse. She is dedicated to improving the quality of life and well-being of underserved women and ensuring that services and programs become accessible to them. Anderson's Award citation is also presented. PMID:23163470

  5. Thermalization and dynamics in the single-impurity Anderson model

    NASA Astrophysics Data System (ADS)

    Weymann, Ireneusz; von Delft, Jan; Weichselbaum, Andreas

    2015-10-01

    We analyze the process of thermalization, dynamics, and the eigenstate thermalization hypothesis (ETH) for the single-impurity Anderson model, focusing on the Kondo regime. For this we construct the complete eigenbasis of the Hamiltonian using the numerical renormalization group (NRG) method in the language of the matrix product states. It is a peculiarity of the NRG that while the Wilson chain is supposed to describe a macroscopic bath, very few single-particle excitations already suffice to essentially thermalize the impurity system at finite temperature, which amounts to having added a macroscopic amount of energy. Thus, given an initial state of the system such as the ground state together with microscopic excitations, we calculate the spectral function of the quantum impurity using the microcanonical and diagonal ensembles. These spectral functions are compared to the time-averaged spectral function obtained by time evolving the initial state according to the full Hamiltonian, and to the spectral function calculated using the thermal density matrix. By adding or removing particles at a certain Wilson energy shell on top of the ground state, we find qualitative agreement between the resulting spectral functions calculated for different ensembles. This indicates that the system thermalizes in the long-time limit, and can be described by an appropriate statistical-mechanical ensemble. Moreover, by calculating static quantities such as the impurity spectral density at the Fermi level as well as the dot occupancy for energy eigenstates relevant for microcanonical ensemble, we find good support for the ETH. The ultimate mechanism responsible for this effective thermalization within the NRG can be identified as Anderson orthogonality: the more charge that needs to flow to or from infinity after applying a local excitation within the Wilson chain, the more the system looks thermal afterwards at an increased temperature. For the same reason, however, thermalization

  6. Breast reconstruction at the MD Anderson Cancer Center.

    PubMed

    Yu, Peirong

    2016-08-01

    The introduction of the transverse rectus abdominis myocutaneous flap in the 1970s marks the beginning of modern breast reconstruction although implants were available even earlier mainly for breast augmentation. Mastectomy techniques have evolved from the early Halsted radical mastectomy to the modern skin sparing mastectomy. The latter made possible using implants for breast reconstruction. Although prosthetic reconstruction provides a simpler procedure with quick recovery, autologous reconstruction offers more natural and long-lasting results especially in the setting of radiotherapy. Both forms have been extensively used at the MD Anderson Cancer Center (MDACC) while microsurgical breast reconstruction has been the hallmark of the MDACC experience. One of the most challenging areas of breast reconstruction is how to achieve good results without compromising adjuvant therapy when post-mastectomy radiotherapy is required. Managing upper extremity lymphedema following breast cancer treatment is another difficult issue which has gained great attention in recent years. This article highlights the important work in various aspects of breast reconstruction that has been done at the MDACC. PMID:27563563

  7. The Knight shift anomaly in the disordered periodic Anderson model

    NASA Astrophysics Data System (ADS)

    Dos Santos, Raimundo; Costa, Natanael; Paiva, Thereza; Curro, Nicholas; Scalettar, Richard

    In some materials, the coherence temperature T* signals the regime in which one has a heavy-electron fluid and `dissolved' local moments. An experimental signature of T* is provided by the Knight shift anomaly in NMR measurements. Further, the contribution of the heavy-electron fluid to the Knigh shift, KHF, displays universal character over a wide range of temperatures. An important probe of the physical mechanisms at play is the random substitution of say, La for Ce in CeRhIn5: this amounts to removing local moments at random sites, and one may wonder whether these universal features are sensitive to the presence of disorder. The Periodic Anderson Model (PAM) captures many aspects of heavy-fermion materials, so here we consider the two-dimensional PAM with a fraction x of the f-sites removed at random. Through Determinant Quantum Monte Carlo simulations we find that universality of KHF persists even in the presence of disorder, which, in turn, allows us to establish that T* decreases monotonically with x, in agreement with available experimental data. Our simulations also shed light into the low temperature behavior of the disordered PAM at low temperatures: the spin liquid phase of the local moments is suppressed upon dilution.

  8. Spin susceptibility of Anderson impurities in arbitrary conduction bands

    NASA Astrophysics Data System (ADS)

    Fang, Tie-Feng; Tong, Ning-Hua; Cao, Zhan; Sun, Qing-Feng; Luo, Hong-Gang

    2015-10-01

    Spin susceptibility of Anderson impurities is a key quantity in understanding the physics of Kondo screening. Traditional numerical renormalization group (NRG) calculation of the impurity contribution χimp to susceptibility, defined originally by Wilson in a flat wide band, has been generalized before to structured conduction bands. The results brought about non-Fermi-liquid and diamagnetic Kondo behaviors in χimp, even when the bands are not gapped at the Fermi energy. Here, we use the full density-matrix (FDM) NRG to present high-quality data for the local susceptibility χloc and to compare them with χimp obtained by the traditional NRG. Our results indicate that those exotic behaviors observed in χimp are unphysical. Instead, the low-energy excitations of the impurity in arbitrary bands only without gap at the Fermi energy are still a Fermi liquid and paramagnetic. We also demonstrate that unlike the traditional NRG yielding χloc less accurate than χimp, the FDM method allows a high-precision dynamical calculation of χloc at much reduced computational cost, with an accuracy at least one order higher than χimp. Moreover, artifacts in the FDM algorithm to χimp and origins of the spurious non-Fermi-liquid and diamagnetic features are clarified. Our work provides an efficient high-precision algorithm to calculate the spin susceptibility of impurity for arbitrary structured bands, while negating the applicability of Wilson's definition to such cases.

  9. Anderson localization in metamaterials and other complex media (Review Article)

    NASA Astrophysics Data System (ADS)

    Gredeskul, Sergey A.; Kivshar, Yuri S.; Asatryan, Ara A.; Bliokh, Konstantin Y.; Bliokh, Yuri P.; Freilikher, Valentin D.; Shadrivov, Ilya V.

    2012-07-01

    This is a review of some recent (mostly ours) results on Anderson localization of light and electron waves in complex disordered systems, including: (i) left-handed metamaterials, (ii) magnetoactive optical structures, (iii) graphene superlattices, and (iv) nonlinear dielectric media. First, we demonstrate that left-handed metamaterials can significantly suppress localization of light and lead to an anomalously enhanced transmission. This suppression is essential at the long-wavelength limit in the case of normal incidence, at specific angles of oblique incidence (Brewster anomaly), and in vicinity of zero-ɛ or zero-μ frequencies for dispersive metamaterials. Remarkably, in disordered samples comprised of alternating normal and left-handed metamaterials, the reciprocal Lyapunov exponent and reciprocal transmittance increment can differ from each other. Second, we study magnetoactive multilayered structures, which exhibit nonreciprocal localization of light depending on the direction of propagation and on polarization. At resonant frequencies or realizations such nonreciprocity results in effectively unidirectional transport of light. Third, we discuss the analogy between wave propagation through multilayered samples with metamaterials and charge transport in graphene, which provides a simple physical explanation of unusual conductive properties of disordered graphene superlatices. We predict disorder-induced resonance of the transmission coefficient at oblique incidence of Dirac quasiparticles. Finally, we demonstrate that an interplay of nonlinearity and disorder in dielectric media can lead to bistability of individual localized states excited inside the medium at resonant frequencies. This results in nonreciprocity of wave transmission and unidirectional transport of light.

  10. Interpreting the flock algorithm: a reply to Anderson & Barry (2015).

    PubMed

    Duchesne, P; Turgeon, J

    2016-01-01

    Anderson & Barry (Molecular Ecology Resources, 2015, 10, 1020-1030) compared a reprogrammed version of flock (Duchesne & Turgeon , Molecular Ecology Resources, 2009, 9, 1333-1344), flockture, to a particular model of structure (Pritchard , Genetics, 2000, 155, 945-959) that they propose is equivalent to flock, a non-MCMC, non-Bayesian algorithm. They conclude that structure performs better than flockture at clustering individuals from simulated populations with very low level of differentiation (FST c. 0.008) based on 15 microsatellites or 96 SNPs. We rather consider that both algorithms failed, with proportions of correct allocations lower than 50%. The authors also noted the slightly better performance of flockture with SNPs at intermediate FST values (c. 0.02-0.04) but did not comment. Finally, we disagree with the way the processing time of each program was compared. When compared on the basis of a run leading to a clustering solution, the main output of any clustering algorithm, flock, is, as users can readily experience, much faster. In all, we feel that flock performs at least as well as structure as a clustering algorithm. Moreover, flock has two major assets: high speed and clear, well validated, rules to estimate K, the number of populations. It thus provides a valuable addition to the set of tools at the disposal of the many researchers dealing with real empirical data sets. PMID:26768196

  11. Anderson metal-insulator transitions with classical magnetic impurities

    NASA Astrophysics Data System (ADS)

    Jung, Daniel; Kettemann, Stefan; Slevin, Keith

    2016-04-01

    We study numerically the effects of classical magnetic impurities on the Anderson metal-insulator transition. We find that a small concentration of Heisenberg impurities enhances the critical disorder amplitude Wc with increasing exchange coupling strength J . The resulting scaling with J is analyzed which supports an anomalous scaling prediction by Wegner due to the combined breaking of time-reversal and spin-rotational symmetry. Moreover, we find that the presence of magnetic impurities lowers the critical correlation length exponent ν and enhances the multifractality parameter α0. The new value of ν improves the agreement with the value measured in experiments on the metal-insulator transition (MIT) in doped semiconductors like phosphor-doped silicon, where a finite density of magnetic moments is known to exist in the vicinity of the MIT. The results are obtained by a finite-size scaling analysis of the geometric mean of the local density of states which is calculated by means of the kernel polynomial method. We establish this combination of numerical techniques as a method to obtain critical properties of disordered systems quantitatively.

  12. (1)/(N) expansion of the nonequilibrium infinite- U Anderson model

    NASA Astrophysics Data System (ADS)

    Ratiani, Zurab; Mitra, Aditi

    2009-06-01

    Results are presented for the nonequilibrium infinite- U Anderson model using a large N approach, where N is the degeneracy of the impurity level, and where nonequilibrium is established by coupling the level to two leads at two different chemical potentials so that there is current flow. A slave-boson representation combined with Keldysh functional integral methods is employed. Expressions for the static spin susceptibility χS and the conductance G are presented to O((1)/(N)) and for an applied voltage difference V less than the Kondo temperature. The correlation function for the slave boson is found to be significantly modified from its equilibrium form in that it acquires a rapid decay in time with a rate that equals the current-induced decoherence rate. Physical observables are found to have a rather complex dependence on the coupling strength to the two leads which can lead to asymmetric behavior χS(V)≠χS(-V) , G(V)≠G(-V) both in the mixed valence and in the Kondo regime.

  13. Analytical Perturbative Treatment of Multiterminal Nonequilibrium Anderson Impurity Models

    NASA Astrophysics Data System (ADS)

    Taniguchi, Nobuhiko

    2015-03-01

    We investigate analytically the nonequilibrium Anderson impurity model connecting with multiterminal leads. Within the validity of the second-order perturbation regarding the interaction strength, the full dependence on frequency and bias voltage of the nonequilibrium self-energy and spectral function is determined for a generic multiterminal setting where the current preservation has been an issue. Our analytical perturbative treatment respects the current conservation as well as the spectral sum rule, and it encompasses Fermi-liquid and non-Fermi liquid behaviors, showing that increasing finite-bias voltage leads to a crossover from the Kondo resonance to the Coulomb blockade phenomena. Analysis on two-terminal and multiterminal settings shows that finite-bias voltage does not split the Kondo resonance in this order; no specific structure due to multiple leads emerges in the spectral function. Overall bias dependence is quite similar to finite-temperature effect, which could be understood by help of the Ward identity and the limit of N >> 1 terminals. Grant-in-Aid for Scientific Research (No. 26400382, MEXT, Japan).

  14. Application of the Gutzwiller method to the periodic Anderson model

    NASA Astrophysics Data System (ADS)

    Fazekas, P.; Brandow, B. H.

    1987-11-01

    The ground state of the orbitally non-degenerate periodic Anderson model is studied variationally. Our Ansatz is the lattice version of the lowest-order Varma-Yafet trial state, with the number of the independent variational parameters being equal to the number of k-states within the Fermi-surface. We employ a two-band version of the Gutzwiller method. The only approximation we make is the replacement of the determinant expressions in the Gutzwiller expansion by their averages. Apart from this, the optimisation problem is solved exactly, and the results can be interpreted in terms of an effective free-fermion Hamiltonian. The renormalisation factor of the hybridisation is of the Rice-Ueda form. A simple model is introduced to get closed-form results in the limit of small hybridisation, and we find the same Kondo exponent as Rice and Ueda. The spin dependence of the effective hybridisation leads to a spin polarisation instability for sufficiently small hybridisation, even within the mixed valent regime.

  15. Kondo hole route to incoherence in the periodic Anderson model

    NASA Astrophysics Data System (ADS)

    Kumar, Pramod; Vidhyadhiraja, N. S.

    2013-03-01

    The interplay of disorder and interactions in strongly correlated electronic systems is a subject of perennial interest. In this work, we have investigated the effect of Kondo-hole type disorder on the dynamics and transport properties of heavy fermion systems. We employ the periodic Anderson model within the framework of coherent potential approximation and dynamical mean field theory. The crossover from lattice coherent behaviour to an incoherent single-impurity behaviour is reflected in all aspects: a highly frequency (ω)-dependent hybridization becomes almost flat, the coherence peak in resistivity (per impurity) gives way to a Hammann form that saturates at low temperature (T); the Drude peak and the mid-infrared peak in the optical conductivity vanish almost completely. The zero temperature resistivity can be captured in a closed form expression, and we show how the Nordheim's rule gets strongly modified in these systems. The thermopower exhibits a characteristic peak, which changes sign with increasing disorder, and its location is shown to correspond to the low energy scale of the system (ωL). In fact, the thermopower appears to be much more sensitive to disorder variations than the resistivity. A comparison to experiments yields quantitative agreement. JNCASR and CSIR

  16. Breast reconstruction at the MD Anderson Cancer Center

    PubMed Central

    2016-01-01

    The introduction of the transverse rectus abdominis myocutaneous flap in the 1970s marks the beginning of modern breast reconstruction although implants were available even earlier mainly for breast augmentation. Mastectomy techniques have evolved from the early Halsted radical mastectomy to the modern skin sparing mastectomy. The latter made possible using implants for breast reconstruction. Although prosthetic reconstruction provides a simpler procedure with quick recovery, autologous reconstruction offers more natural and long-lasting results especially in the setting of radiotherapy. Both forms have been extensively used at the MD Anderson Cancer Center (MDACC) while microsurgical breast reconstruction has been the hallmark of the MDACC experience. One of the most challenging areas of breast reconstruction is how to achieve good results without compromising adjuvant therapy when post-mastectomy radiotherapy is required. Managing upper extremity lymphedema following breast cancer treatment is another difficult issue which has gained great attention in recent years. This article highlights the important work in various aspects of breast reconstruction that has been done at the MDACC. PMID:27563563

  17. Anderson metal-insulator transitions with classical magnetic impurities

    SciTech Connect

    Jung, Daniel; Kettemann, Stefan

    2014-08-20

    We study the effects of classical magnetic impurities on the Anderson metal-insulator transition (AMIT) numerically. In particular we find that while a finite concentration of Ising impurities lowers the critical value of the site-diagonal disorder amplitude W{sub c}, in the presence of Heisenberg impurities, W{sub c} is first increased with increasing exchange coupling strength J due to time-reversal symmetry breaking. The resulting scaling with J is compared to analytical predictions by Wegner [1]. The results are obtained numerically, based on a finite-size scaling procedure for the typical density of states [2], which is the geometric average of the local density of states. The latter can efficiently be calculated using the kernel polynomial method [3]. Although still suffering from methodical shortcomings, our method proves to deliver results close to established results for the orthogonal symmetry class [4]. We extend previous approaches [5] by combining the KPM with a finite-size scaling analysis. We also discuss the relevance of our findings for systems like phosphor-doped silicon (Si:P), which are known to exhibit a quantum phase transition from metal to insulator driven by the interplay of both interaction and disorder, accompanied by the presence of a finite concentration of magnetic moments [6].

  18. Anderson metal-insulator transitions with classical magnetic impurities

    NASA Astrophysics Data System (ADS)

    Jung, Daniel; Kettemann, Stefan

    2014-08-01

    We study the effects of classical magnetic impurities on the Anderson metal-insulator transition (AMIT) numerically. In particular we find that while a finite concentration of Ising impurities lowers the critical value of the site-diagonal disorder amplitude Wc, in the presence of Heisenberg impurities, Wc is first increased with increasing exchange coupling strength J due to time-reversal symmetry breaking. The resulting scaling with J is compared to analytical predictions by Wegner [1]. The results are obtained numerically, based on a finite-size scaling procedure for the typical density of states [2], which is the geometric average of the local density of states. The latter can efficiently be calculated using the kernel polynomial method [3]. Although still suffering from methodical shortcomings, our method proves to deliver results close to established results for the orthogonal symmetry class [4]. We extend previous approaches [5] by combining the KPM with a finite-size scaling analysis. We also discuss the relevance of our findings for systems like phosphor-doped silicon (Si:P), which are known to exhibit a quantum phase transition from metal to insulator driven by the interplay of both interaction and disorder, accompanied by the presence of a finite concentration of magnetic moments [6].

  19. Modified Anderson orthogonality catastrophe power law in the presence of shell structure

    NASA Astrophysics Data System (ADS)

    Bandopadhyay, Swarnali; Hentschel, Martina

    2011-01-01

    We study Anderson orthogonality catastrophe (AOC) for parabolic quantum dots and focus on the effects of degeneracies, realized through the inherent shell structure of their energy levels that can be lifted through an external magnetic field, on the Anderson overlap. We find rich and interesting behaviors as a function of the strength and position of the perturbation, the system size, and the applied magnetic field. In particular, even for weak perturbations, we observe a pronounced AOC that is related to the degeneracy of energy levels. Most importantly, the power-law decay of the Anderson overlap as a function of the number of particles is modified in comparison to the metallic case due to the rearrangement of the energy-level shell structure. We support our analytical results by numerical calculations and also study the distribution of Anderson overlaps.

  20. Adaptive Thouless-Anderson-Palmer approach to inverse Ising problems with quenched random fields.

    PubMed

    Huang, Haiping; Kabashima, Yoshiyuki

    2013-06-01

    The adaptive Thouless-Anderson-Palmer equation is derived for inverse Ising problems in the presence of quenched random fields. We test the proposed scheme on Sherrington-Kirkpatrick, Hopfield, and random orthogonal models and find that the adaptive Thouless-Anderson-Palmer approach allows accurate inference of quenched random fields whose distribution can be either Gaussian or bimodal. In particular, another competitive method for inferring external fields, namely, the naive mean field method with diagonal weights, is compared and discussed. PMID:23848649

  1. Luminescent Copper(I) Halide Butterfly Dimers Coordinated to [Au(CH3imCH2py)2]BF4 and [Au(CH3imCH2quin)2]BF4

    SciTech Connect

    Catalano, V.; Moore, A; Shearer, J; Kim, J

    2009-01-01

    The coordination chemistry of copper(I) halides to the homoleptic, N-heterocyclic carbene Au(I) complexes [Au(CH{sub 3}imCH{sub 2}quin){sub 2}]BF{sub 4} and [Au(CH{sub 3}imCH{sub 2}py){sub 2}]BF{sub 4} was explored. The reaction of CuX (X = Cl, Br, I) with either [Au(CH{sub 3}imCH{sub 2}quin){sub 2}]BF{sub 4} or [Au(CH{sub 3}imCH{sub 2}py){sub 2}]BF{sub 4} produces trimetallic complexes containing Cu{sub 2}X{sub 2}-butterfly copper clusters coordinated to the two imine moieties. The triangular arrangement of the metals places the gold(I) center in close proximity ({approx}2.5-2.6 {angstrom}) to the centroid of the Cu-Cu vector. The Cu-Cu separations vary as a function of bridging halide with the shortest Cu-Cu separations of {approx}2.5 {angstrom} found in the iodo-complexes and the longest separations of 2.9 {angstrom} found in the bridging chloride complexes. In all six complexes the Au-Cu separations range from {approx}2.8 to 3.0 {angstrom}. In the absence of halides, the dimetallic complex [AuCu(CH{sub 3}imCH{sub 2}py){sub 2}(NCCH{sub 3}){sub 2}](BF{sub 4}){sub 2}, containing a long Au-Cu distance of {approx}4.72 {angstrom} is formed. Additionally, as the byproduct of the reaction of CuBr with [Au(CH{sub 3}imCH{sub 2}quin){sub 2}]BF{sub 4} the deep-red, dimetallic compound, AuCuBr{sub 2}(CH{sub 3}imCH{sub 2}quin){sub 2}, was isolated in very low yield. All of these complexes were studied by NMR spectroscopy, mass spectrometry, and the copper containing species were additionally characterized by X-ray crystallography. In solution the copper centers dissociate from the gold complexes, but as shown by XANES and EXAFS spectroscopy, at low temperature the Cu-Cu linkage is broken, and the individual copper(I) halides reposition themselves to opposite sides of the gold complex while remaining coordinated to one imine moiety. In the solid state all of the complexes are photoluminescent, though the nature of the excited state was not determined.

  2. Luminescent copper(I) halide butterfly dimers coordinated to [Au(CH3imCH2py)2]BF4 and [Au(CH3imCH2quin)2]BF4.

    PubMed

    Catalano, Vincent J; Moore, Adam L; Shearer, Jason; Kim, Jineun

    2009-12-01

    The coordination chemistry of copper(I) halides to the homoleptic, N-heterocyclic carbene Au(I) complexes [Au(CH(3)imCH(2)quin)(2)]BF(4) and Au(CH(3)imCH(2)py)(2)]BF(4) was explored. The reaction of CuX (X = Cl, Br, I) with either [Au(CH(3)imCH(2)quin)(2)]BF(4) or [Au(CH(3)imCH(2)py)(2)]BF(4) produces trimetallic complexes containing Cu(2)X(2)-butterfly copper clusters coordinated to the two imine moieties. The triangular arrangement of the metals places the gold(I) center in close proximity (approximately 2.5-2.6 A) to the centroid of the Cu-Cu vector. The Cu-Cu separations vary as a function of bridging halide with the shortest Cu-Cu separations of approximately 2.5 A found in the iodo-complexes and the longest separations of 2.9 A found in the bridging chloride complexes. In all six complexes the Au-Cu separations range from approximately 2.8 to 3.0 A. In the absence of halides, the dimetallic complex [AuCu(CH(3)imCH(2)py)(2)(NCCH(3))(2)](BF(4))(2), containing a long Au-Cu distance of approximately 4.72 A is formed. Additionally, as the byproduct of the reaction of CuBr with [Au(CH(3)imCH(2)quin)(2)]BF(4) the deep-red, dimetallic compound, AuCuBr(2)(CH(3)imCH(2)quin)(2), was isolated in very low yield. All of these complexes were studied by NMR spectroscopy, mass spectrometry, and the copper containing species were additionally characterized by X-ray crystallography. In solution the copper centers dissociate from the gold complexes, but as shown by XANES and EXAFS spectroscopy, at low temperature the Cu-Cu linkage is broken, and the individual copper(I) halides reposition themselves to opposite sides of the gold complex while remaining coordinated to one imine moiety. In the solid state all of the complexes are photoluminescent, though the nature of the excited state was not determined. PMID:19899779

  3. Parabolic Anderson Model in a Dynamic Random Environment: Random Conductances

    NASA Astrophysics Data System (ADS)

    Erhard, D.; den Hollander, F.; Maillard, G.

    2016-06-01

    The parabolic Anderson model is defined as the partial differential equation ∂ u( x, t)/ ∂ t = κ Δ u( x, t) + ξ( x, t) u( x, t), x ∈ ℤ d , t ≥ 0, where κ ∈ [0, ∞) is the diffusion constant, Δ is the discrete Laplacian, and ξ is a dynamic random environment that drives the equation. The initial condition u( x, 0) = u 0( x), x ∈ ℤ d , is typically taken to be non-negative and bounded. The solution of the parabolic Anderson equation describes the evolution of a field of particles performing independent simple random walks with binary branching: particles jump at rate 2 d κ, split into two at rate ξ ∨ 0, and die at rate (- ξ) ∨ 0. In earlier work we looked at the Lyapunov exponents λ p(κ ) = limlimits _{tto ∞} 1/t log {E} ([u(0,t)]p)^{1/p}, quad p in {N} , qquad λ 0(κ ) = limlimits _{tto ∞} 1/2 log u(0,t). For the former we derived quantitative results on the κ-dependence for four choices of ξ : space-time white noise, independent simple random walks, the exclusion process and the voter model. For the latter we obtained qualitative results under certain space-time mixing conditions on ξ. In the present paper we investigate what happens when κΔ is replaced by Δ𝓚, where 𝓚 = {𝓚( x, y) : x, y ∈ ℤ d , x ˜ y} is a collection of random conductances between neighbouring sites replacing the constant conductances κ in the homogeneous model. We show that the associated annealed Lyapunov exponents λ p (𝓚), p ∈ ℕ, are given by the formula λ p({K} ) = {sup} {λ p(κ ) : κ in {Supp} ({K} )}, where, for a fixed realisation of 𝓚, Supp(𝓚) is the set of values taken by the 𝓚-field. We also show that for the associated quenched Lyapunov exponent λ 0(𝓚) this formula only provides a lower bound, and we conjecture that an upper bound holds when Supp(𝓚) is replaced by its convex hull. Our proof is valid for three classes of reversible ξ, and for all 𝓚

  4. Attractive Hubbard model with disorder and the generalized Anderson theorem

    SciTech Connect

    Kuchinskii, E. Z. Kuleeva, N. A. Sadovskii, M. V.

    2015-06-15

    Using the generalized DMFT+Σ approach, we study the influence of disorder on single-particle properties of the normal phase and the superconducting transition temperature in the attractive Hubbard model. A wide range of attractive potentials U is studied, from the weak coupling region, where both the instability of the normal phase and superconductivity are well described by the BCS model, to the strong-coupling region, where the superconducting transition is due to Bose-Einstein condensation (BEC) of compact Cooper pairs, formed at temperatures much higher than the superconducting transition temperature. We study two typical models of the conduction band with semi-elliptic and flat densities of states, respectively appropriate for three-dimensional and two-dimensional systems. For the semi-elliptic density of states, the disorder influence on all single-particle properties (e.g., density of states) is universal for an arbitrary strength of electronic correlations and disorder and is due to only the general disorder widening of the conduction band. In the case of a flat density of states, universality is absent in the general case, but still the disorder influence is mainly due to band widening, and the universal behavior is restored for large enough disorder. Using the combination of DMFT+Σ and Nozieres-Schmitt-Rink approximations, we study the disorder influence on the superconducting transition temperature T{sub c} for a range of characteristic values of U and disorder, including the BCS-BEC crossover region and the limit of strong-coupling. Disorder can either suppress T{sub c} (in the weak-coupling region) or significantly increase T{sub c} (in the strong-coupling region). However, in all cases, the generalized Anderson theorem is valid and all changes of the superconducting critical temperature are essentially due to only the general disorder widening of the conduction band.

  5. Chemotherapy for bone sarcomas in adults: the MD anderson experience.

    PubMed

    Benjamin, Robert S; Wagner, Michael J; Livingston, J Andrew; Ravi, Vinod; Patel, Shreyaskumar R

    2015-01-01

    Increasing age is an adverse prognostic factor in the treatment of primary bone tumors. There are few published data on treatment of primary bone tumors in adults. This paper presents data from the Department of Sarcoma Medical Oncology at The University of Texas MD Anderson Cancer Center, summarizing our treatment results. To treat primary osteosarcoma, we used 90 mg/m2 of doxorubicin as a continuous intravenous infusion over 48 to 96 hours and 120 to 160 mg/m2 of cisplatin intravenously or intra-arterially. Initially, we found a marked difference in postoperative continuous disease-free survival (CDFS) between those with 90% or greater (i.e., good response) tumor necrosis and those with less than 90% (i.e., poor response) tumor necrosis. The sequential addition of high-dose methotrexate and ifosfamide to patients with poorly responding disease improved their CDFS to that of patients with good response. Older patients and those who have tumors with variant histology have inferior outcomes. Evaluation of subsequent patients revealed similar outcomes for those with good or poor response to induction therapy, supporting our practice of adaptation of postoperative chemotherapy to the results of preoperative chemotherapy. PET-CT is the best imaging modality to screen for a response with tumors inside bone. To treat Ewing sarcoma, we have employed 2 mg of vincristine, 75 to 90 mg/m2 of doxorubicin as a 72-hour infusion, and 2.5 g/m2 of ifosfamide over 3 hours daily for 4 doses (i.e., vincristine, doxorubicin, and ifosfamide [VAI]). Preliminary analysis indicates a higher CDFS when adjusted for patient age than seen with the standard alternating regimen used in pediatrics. A screening MRI of the pelvis and spine can detect subtle metastatic disease in bone or bone marrow that is missed by other imaging modalities or blind biopsy. Chondrosarcoma is treated surgically or on investigational protocols. Giant cell tumor of bone is usually managed surgically, but multiple

  6. Anderson localization to enhance light-matter interaction (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Garcia, Pedro David

    2016-04-01

    Deliberately introducing disorder in low-dimensional nanostructures like photonic crystal waveguides (PCWs) [1] or photonic crystals (PCs) [2] leads to Anderson localization where light is efficiently trapped by random multiple scattering with the lattice imperfections. These disorder-induced optical modes hace been demonstrated to be very promising for cavity-quantum electrodynamics (QED) experiments where the radiative emission rate of single quantum emitters can be controlled when tuned through resonance with one of these random cavities. Our statistical analysis of the emission dynamics from single quantum dots embeded in disordered PCWs [3] provides detailed insigth about the statistical properties of QED in these complex nanostructures. In addition, using internal light sources reveals new physics in the form of nonuniversal intensity correlations between the different scattered paths within the structure which imprint the local QED properties deep inside the complex structure onto the far-field intensity pattern [2]. Finally, increasing the optical gain in PCWs allows on-chip random nanolasing where the cavity feedback is provided by the intrinsic disorder which enables highly efficient, stable, and broadband tunable lasers with very small mode volumes [4]. The figure of merit of these disorder-induced cavities is their localization length which determines to a large degree the coupling efficiency of a quantum emitter to a disorder-induced cavity as well as the efficiency of random lasing and reveals a strongly dispersive behavior and a non-trivial dependence on disorder in PCWs [5]. [1] L. Sapienza, H. Thyrrestrup, S. Stobbe, P.D. Garcia, S. Smolka, and P. Lodahl, Science 327, 1352 (2010). [2] P. D. García, S. Stobbe, I. Soellner and P. Lodahl, Physical Review Letters 109, 253902 (2012). [3] A. Javadi, S. Maibom, L. Sapienza, H. Thyrrestrup, P.D. Garcia, and P. Lodahl, Opt. Express 22, 30992 (2014). [4] J. Liu, P. D. Garcia, S. Ek, N. Gregersen, T. Suhr, M

  7. Exciting Molecules Close to the Rotational Quantum Resonance: Anderson Wall and Rotational Bloch Oscillations.

    PubMed

    Floß, Johannes; Averbukh, Ilya Sh

    2016-05-19

    We describe a universal behavior of linear molecules excited by a periodic train of short laser pulses under conditions close to the quantum resonance. The quantum resonance effect causes an unlimited ballistic growth of the angular momentum. We show that a disturbance of the quantum resonance, either by the centrifugal distortion of the rotating molecules or a controlled detuning of the pulse train period from the so-called rotational revival time, eventually halts the growth by causing Anderson localization beyond a critical value of the angular momentum, the Anderson wall. Below the wall, the rotational excitation oscillates with the number of pulses due to a mechanism similar to Bloch oscillations in crystalline solids. We suggest optical experiments capable of observing the rotational Anderson wall and Bloch oscillations at near-ambient conditions with the help of existing laser technology. PMID:26799273

  8. John Anderson's development of (situational) realism and its bearing on psychology today.

    PubMed

    Hibberd, Fiona J

    2009-10-01

    In 1927, the Scottish philosopher John Anderson arrived in Australia to take up the chair of Philosophy at the University of Sydney. By the late 1930s, the "macrostructure" of his realist system was in place. It includes a theory of process and a substantial metaphysics, one that opposes positivism, linguistic philosophy and all forms of idealism. However, beyond Australia it remains largely unknown, despite its bearing on a number of current issues in psychology and the social sciences generally. This article outlines Anderson's transition from Hegelian idealism to realism, describes aspects of his ontology and epistemology, compares some of Anderson's ideas with Dewey's pragmatism and explains their relevance to present-day psychology. PMID:20027696

  9. Anderson Localization from the Berry-Curvature Interchange in Quantum Anomalous Hall Systems

    NASA Astrophysics Data System (ADS)

    Qiao, Zhenhua; Han, Yulei; Zhang, Lei; Wang, Ke; Deng, Xinzhou; Jiang, Hua; Yang, Shengyuan A.; Wang, Jian; Niu, Qian

    2016-07-01

    We theoretically investigate the localization mechanism of the quantum anomalous Hall effect (QAHE) in the presence of spin-flip disorders. We show that the QAHE stays quantized at weak disorders, then enters a Berry-curvature mediated metallic phase at moderate disorders, and finally goes into the Anderson insulating phase at strong disorders. From the phase diagram, we find that at the charge neutrality point although the QAHE is most robust against disorders, the corresponding metallic phase is much easier to be localized into the Anderson insulating phase due to the interchange of Berry curvatures carried, respectively, by the conduction and valence bands. In the end, we provide a phenomenological picture related to the topological charges to better understand the underlying physical origin of the QAHE Anderson localization.

  10. Anderson Localization from the Berry-Curvature Interchange in Quantum Anomalous Hall Systems.

    PubMed

    Qiao, Zhenhua; Han, Yulei; Zhang, Lei; Wang, Ke; Deng, Xinzhou; Jiang, Hua; Yang, Shengyuan A; Wang, Jian; Niu, Qian

    2016-07-29

    We theoretically investigate the localization mechanism of the quantum anomalous Hall effect (QAHE) in the presence of spin-flip disorders. We show that the QAHE stays quantized at weak disorders, then enters a Berry-curvature mediated metallic phase at moderate disorders, and finally goes into the Anderson insulating phase at strong disorders. From the phase diagram, we find that at the charge neutrality point although the QAHE is most robust against disorders, the corresponding metallic phase is much easier to be localized into the Anderson insulating phase due to the interchange of Berry curvatures carried, respectively, by the conduction and valence bands. In the end, we provide a phenomenological picture related to the topological charges to better understand the underlying physical origin of the QAHE Anderson localization. PMID:27517785

  11. Financial protection against nuclear hazards: thirty years' experience under the Price-Anderson Act

    SciTech Connect

    Rockett, L.R.; Hayn, I.

    1984-01-01

    The purpose of this study is to evaluate the operation of the Price-Anderson Act in the light of the last 10 years' experience and the changes that have occurred during that period both in the law and regulations and in the nuclear and insurance industries, and to provide an independent analysis of various proposals to extend or amend the Act prior to its 1987 expiration. The report does not analyze the impact of the Silkwood v. Kerr McGee Corp. decision. The five chapters cover historical background, financial protection under the Price-Anderson Act and in the absence of the Act, fundamental policy issues, and alternative proposals.

  12. Designed Assembly of Heterometallic Cluster Organic Frameworks Based on Anderson-Type Polyoxometalate Clusters.

    PubMed

    Li, Xin-Xiong; Wang, Yang-Xin; Wang, Rui-Hu; Cui, Cai-Yan; Tian, Chong-Bin; Yang, Guo-Yu

    2016-05-23

    A new approach to prepare heterometallic cluster organic frameworks has been developed. The method was employed to link Anderson-type polyoxometalate (POM) clusters and transition-metal clusters by using a designed rigid tris(alkoxo) ligand containing a pyridyl group to form a three-fold interpenetrated anionic diamondoid structure and a 2D anionic layer, respectively. This technique facilitates the integration of the unique inherent properties of Anderson-type POM clusters and cuprous iodide clusters into one cluster organic framework. PMID:27061042

  13. Interaction effect in the Kondo energy of the periodic Anderson-Hubbard model

    NASA Astrophysics Data System (ADS)

    Itai, K.; Fazekas, P.

    1996-07-01

    We extend the periodic Anderson model by switching on a Hubbard U for the conduction band. The nearly integral valent limit of the Anderson-Hubbard model is studied with the Gutzwiller variational method. The lattice Kondo energy shows U dependence both in the prefactor and the exponent. Switching on U reduces the Kondo scale, which can be understood to result from the blocking of hybridization. At half filling, we find a Brinkman-Rice-type transition from a Kondo insulator to a Mott insulator. Our findings should be relevant for a number of correlated two-band models of recent interest.

  14. Entanglement Area Law in Disordered Free Fermion Anderson Model in One, Two, and Three Dimensions

    DOE PAGESBeta

    Pouranvari, Mohammad; Zhang, Yuhui; Yang, Kun

    2015-01-01

    We calculate numerically the entanglement entropy of free fermion ground states in one-, two-, and three-dimensional Anderson models and find that it obeys the area law as long as the linear size of the subsystem is sufficiently larger than the mean free path. This result holds in the metallic phase of the three-dimensional Anderson model, where the mean free path is finite although the localization length is infinite. Relation between the present results and earlier ones on area law violation in special one-dimensional models that support metallic phases is discussed.

  15. Wildlife Impact Assessment: Anderson Ranch, Black Canyon, and Boise Diversion Projects, Idaho. Final Report.

    SciTech Connect

    Meuleman, G. Allyn

    1986-05-01

    This report presents an analysis of impacts on wildlife and their habitats as a result of construction and operation of the US Bureau of Reclamation's Anderson Ranch, Black Canyon, and Boise Diversion Projects in Idaho. The objectives were to: (1) determine the probable impacts of development and operation of the Anderson Ranch, Black Canyon, and Boise Diversion Projects to wildlife and their habitats; (2) determine the wildlife and habitat impacts directly attributable to hydroelectric development and operation; (3) briefly identify the current major concerns for wildlife in the vicinities of the hydroelectric projects; and (4) provide for consultation and coordination with interested agencies, tribes, and other entities expressing interest in the project.

  16. Dimensional Dependence of Critical Exponent of the Anderson Transition in the Orthogonal Universality Class

    NASA Astrophysics Data System (ADS)

    Ueoka, Yoshiki; Slevin, Keith

    2014-08-01

    We report improved numerical estimates of the critical exponent of the Anderson transition in Anderson’s model of localization in d = 4 and 5 dimensions. We also report a new Borel-Padé analysis of existing ɛ expansion results that incorporates the asymptotic behavior for d → ∞ and gives better agreement with available numerical results.

  17. Adolescent Identities and Sexual Behavior: An Examination of Anderson's Player Hypothesis

    ERIC Educational Resources Information Center

    Giordano, Peggy C.; Longmore, Monica A.; Manning, Wendy D.; Northcutt, Miriam J.

    2009-01-01

    We investigate the social and behavioral characteristics of male adolescents who self-identify as players, focusing particularly on Anderson's claim that this social role is inextricably linked with poverty and minority status. Results indicate that black respondents, those affiliated with liberal peers and young men who initially report a…

  18. Melissa L. Anderson: APA/APAGS Award for Distinguished Graduate Student in Professional Psychology

    ERIC Educational Resources Information Center

    American Psychologist, 2012

    2012-01-01

    Presents a short biography of the winner of the American Psychological Association/American Psychological Association of Graduate Students Award for Distinguished Graduate Student in Professional Psychology. The 2012 winner is Melissa L. Anderson for her ongoing commitment to understanding, treating, and preventing domestic violence in Deaf women…

  19. 4. VIEW OF SITE A FROM ANDERSON WAY, FACING SOUTH/SOUTHWEST. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. VIEW OF SITE A FROM ANDERSON WAY, FACING SOUTH/SOUTHWEST. (BUILDINGS 126, 124, 122, 120, and 114 ARE VISIBLE.) - Fort McPherson, World War II Station Hospital, Structures, Bordered by Hardee & Thorne Avenues & Howe Street, Atlanta, Fulton County, GA

  20. AUTO ANSWER CIRCUIT DESIGN FOR AN ANDERSON JACOBSON AD 342 MODEM

    EPA Science Inventory

    The report describes a circuit which connects a Western Electric Model 1001F Data Accessing Arrangement to an Anderson Jacobson Model AD 342 Modem. It automatically answers the phone and holds a data connection as long as a received carrier is present. It self resets upon loss of...

  1. Dystopian Visions of Global Capitalism: Philip Reeve's "Mortal Engines" and M.T Anderson's "Feed"

    ERIC Educational Resources Information Center

    Bullen, Elizabeth; Parsons, Elizabeth

    2007-01-01

    This article examines Philip Reeve's novel for children, "Mortal Engines", and M.T. Anderson's young adult novel, "Feed", by assessing these dystopias as prototypical texts of what Ulrich Beck calls risk society. Through their visions of a fictional future, the two narratives explore the hazards created by contemporary techno-economic progress,…

  2. Single-ion-pair fluorescence ratios in ruby and Anderson localization

    NASA Astrophysics Data System (ADS)

    Chu, S.; Gibbs, H. M.; Passner, A.

    1981-12-01

    The experiment of Koo, Walker, and Geschwind (KWG) presenting evidence for a mobility edge separating localized and extended states has been repeated and extended. Although some of the features reported by KWG were seen, there are notable qualitative and quantitative differences in our work. We conclude that there is no compelling evidence for an Anderson transition in ruby.

  3. Between Voice and Voicelessness: Transacting Silence in Laurie Halse Anderson's "Speak."

    ERIC Educational Resources Information Center

    O'Quinn, Elaine J.

    2001-01-01

    Describes how Laurie Halse Anderson's insightful novel, "Speak" (1999), reminds readers of the distance women have come in identifying the "oppressive and unhealthy behavior of the silences that so often betray them." Concludes that the oppression of silence which generations of women have stoically accepted is now being challenged publicly and…

  4. 78 FR 41835 - Inflation Adjustments to the Price-Anderson Act Financial Protection Regulations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-12

    ... consistent with the Plain Writing Act as well as the Presidential Memorandum, ``Plain Language in Government... made the initial changes to the Price-Anderson Act amounts on October 27, 2005 (70 FR 61885), and the first periodic inflation adjustments on September 29, 2008 (73 FR 56451). This final rule makes...

  5. Wildlife Protection, Mitigation, and Enhancement Plans, Anderson Ranch and Black Canyon Facilities: Final Report.

    SciTech Connect

    Meuleman, G. Allyn

    1987-06-01

    Under direction of the Pacific Northwest Electric Power Planning and Conservation Act of 1980, and the subsequent Northwest Power Planning Council's Columbia River Basin Fish and Wildlife Program, projects have been developed in Idaho to mitigate the impacts to wildlife habitat and production due to the development and operation of the Anderson Ranch and Black Canyon Facilities (i.e., dam, power plant, and reservoir areas). The Anderson Ranch Facility covered about 4812 acres of wildlife habitat while the Black Canyon Facility covered about 1115 acres. These acreages include dam and power plant staging areas. A separate mitigation plan has been developed for each facility. A modified Habitat Evaluation Procedure (HEP) was used to assess the benefits of the mitigation plans to wildlife. The interagency work group used the target species Habitat Units (HU's) lost at each facility as a guideline during the mitigation planning process, while considering the needs of wildlife in the areas. Totals of 9619 and 2238 target species HU's were estimated to be lost in the Anderson Ranch and Black Canyon Facility areas, respectively. Through a series of projects, the mitigation plans will provide benefits of 9620 target species HU's to replace Anderson Ranch wildlife impacts and benefits of 2195 target species HU's to replace Black Canyon wildlife impacts. Target species to be benefited by the Anderson Ranch and/or Black Canyon mitigation plans include the mallard, Canada goose, mink, yellow warbler, black-capped chickadee, ruffed grouse, mule deer, blue grouse, sharp-tailed grouse, ring-necked pheasant, and peregrine falcon.

  6. Covalent attachment of Anderson-type polyoxometalates to single-walled carbon nanotubes gives enhanced performance electrodes for lithium ion batteries.

    PubMed

    Ji, Yuanchun; Hu, Jun; Huang, Lujiang; Chen, Wei; Streb, Carsten; Song, Yu-Fei

    2015-04-20

    Single-walled carbon nanotubes (SWNTs) covalently functionalized with redox-active organo-modified polyoxometalate (POM) clusters have been synthesized and employed as electrode materials in lithium ion batteries. The Anderson cluster [MnMo6 O24 ](9-) is functionalized with Tris (NH2 C(CH2 OH)3 ) moieties, giving the new organic-inorganic hybrid [N(nC4 H9 )4 ]3 [MnMo6 O18 {(OCH2 )3 CNH2 }2 ]. The compound is then covalently attached to carboxylic acid-functionalized SWNTs by amide bond formation and the stability of this nanocomposite is confirmed by various spectroscopic methods. Electrochemical analyses show that the nanocomposite displays improved performance as an anode material in lithium ion batteries compared with the individual components, that is, SWNTs and/or Anderson clusters. High discharge capacities of up to 932 mAh g(-1) at a current density of 0.5 mA cm(-2) can be observed, together with high long-term cycling stability and decreased electrochemical impedance. Chemisorption of the POM cluster on the SWNTs is shown to give better electrode performance than the purely physisorbed analogues. PMID:25765945

  7. Observation of Anderson localization in ultrathin films of three-dimensional topological insulators.

    PubMed

    Liao, Jian; Ou, Yunbo; Feng, Xiao; Yang, Shuo; Lin, Chaojing; Yang, Wenmin; Wu, Kehui; He, Ke; Ma, Xucun; Xue, Qi-Kun; Li, Yongqing

    2015-05-29

    Anderson localization, the absence of diffusive transport in disordered systems, has been manifested as hopping transport in numerous electronic systems, whereas in recently discovered topological insulators it has not been directly observed. Here, we report experimental demonstration of a crossover from diffusive transport in the weak antilocalization regime to variable range hopping transport in the Anderson localization regime with ultrathin (Bi_{1-x}Sb_{x})_{2}Te_{3} films. As disorder becomes stronger, negative magnetoconductivity due to the weak antilocalization is gradually suppressed, and eventually, positive magnetoconductivity emerges when the electron system becomes strongly localized. This work reveals the critical role of disorder in the quantum transport properties of ultrathin topological insulator films, in which theories have predicted rich physics related to topological phase transitions. PMID:26066450

  8. Characterization of the heartworm Acanthocheilonema spirocauda (Leidy, 1858) Anderson, 1992 (Nematoda: Onchocercidae) in Scandinavia.

    PubMed

    Leidenberger, Sonja; Boström, Sven

    2008-12-01

    The heartworm Acanthocheilonema spirocauda (Leidy, Proc Acad Nat Sci Philadelphia 10:110-112, 1858) Anderson, 1992 is described from material collected from harbour seals in Scandinavia and compared with types and other specimens described by Anderson (Can J Zool 37:481-493, 1959) from harbour seals in eastern USA. Most morphometric characters of the material from USA fall within the ranges established for the Scandinavian one. Some intraspecific variability in the organisation of papillae on the male tail was detected among the Scandinavian specimens. Differences between the specimens from Scandinavia and Eastern USA are also found in the organisation of papillae on the tail of males and females. An excretory pore was not discernible, but a clearly hemizonid-like structure is described. For the first time, scanning electron micrographs present external morphological structures of the species. PMID:18762981

  9. Magnetic frustration in the three-band Anderson lattice model for high-temperature superconductors

    SciTech Connect

    Ihle, D.; Kasner, M. )

    1990-09-01

    The three-band Anderson lattice model for the CuO{sub 2} planes in high-{Tc} superconductors is established. Treating this model by perturbation theory, the effective spin interactions are derived. The antiferromagnetic superexchange integrals are calculated as functions of the direct oxygen transfer and the hole concentration. It is found that frustration in the superexchange occurs, even in the undoped case, which increases with oxygen trnasfer and decreases with hole concentration.

  10. Analysis of the characteristics of patients with open tibial fractures of Gustilo and Anderson type III☆

    PubMed Central

    Jaña Neto, Frederico Carlos; de Paula Canal, Marina; Alves, Bernardo Aurélio Fonseca; Ferreira, Pablício Martins; Ayres, Jefferson Castro; Alves, Robson

    2016-01-01

    Objective To analyze the characteristics of patients with Gustilo–Anderson Type III open tibial fractures treated at a tertiary care hospital in São Paulo between January 2013 and August 2014. Methods This was a cross-sectional retrospective study. The following data were gathered from the electronic medical records: age; gender; diagnosis; trauma mechanism; comorbidities; associated fractures; Gustilo and Anderson, Tscherne and AO classifications; treatment (initial and definitive); presence of compartment syndrome; primary and secondary amputations; MESS (Mangled Extremity Severity Score) index; mortality rate; and infection rate. Results 116 patients were included: 81% with fracture type IIIA, 12% IIIB and 7% IIIC; 85% males; mean age 32.3 years; and 57% victims of motorcycle accidents. Tibial shaft fractures were significantly more prevalent (67%). Eight patients were subjected to amputation: one primary case and seven secondary cases. Types IIIC (75%) and IIIB (25%) predominated among the patients subjected to secondary amputation. The MESS index was greater than 7 in 88% of the amputees and in 5% of the limb salvage group. Conclusion The profile of patients with open tibial fracture of Gustilo and Anderson Type III mainly involved young male individuals who were victims of motorcycle accidents. The tibial shaft was the segment most affected. Only 7% of the patients underwent amputation. Given the current controversy in the literature about amputation or salvage of severely injured lower limbs, it becomes necessary to carry out prospective studies to support clinical decisions. PMID:27069881

  11. Anderson localization of electrons in single crystals: Li (x) Fe(7)Se(8).

    PubMed

    Ying, Tianping; Gu, Yueqiang; Chen, Xiao; Wang, Xinbo; Jin, Shifeng; Zhao, Linlin; Zhang, Wei; Chen, Xiaolong

    2016-02-01

    Anderson (disorder-induced) localization, proposed more than half a century ago, has inspired numerous efforts to explore the absence of wave diffusions in disordered media. However, the proposed disorder-induced metal-insulator transition (MIT), associated with the nonpropagative electron waves, has hardly been observed in three-dimensional (3D) crystalline materials, let alone single crystals. We report the observation of an MIT in centimeter-size single crystals of Li x Fe7Se8 induced by lattice disorder. Both specific heat and infrared reflectance measurements reveal the presence of considerable electronic states in the vicinity of the Fermi level when the MIT occurs, suggesting that the transition is not due to Coulomb repulsion mechanism. The 3D variable range hopping regime evidenced by electrical transport measurements at low temperatures indicates the localized nature of the electronic states on the Fermi level. Quantitative analyses of carrier concentration, carrier mobility, and simulated density of states (DOS) fully support that Li x Fe7Se8 is an Anderson insulator. On the basis of these results, we provide a unified DOS picture to explain all the experimental results, and a schematic diagram for finding other potential Anderson insulators. This material will thus serve as a rich playground for both theoretical and experimental investigations on MITs and disorder-induced phenomena. PMID:26989781

  12. Controlled Triol-Derivative Bonding and Decoration Transformation on Cu-Centered Anderson-Evans Polyoxometalates.

    PubMed

    Wang, Yang; Li, Bao; Qian, Hujun; Wu, Lixin

    2016-05-01

    To create new types of organic ligands covalently grafted onto polyoxometalates and identify the reaction mechanism, we selected Cu(II) as the central heteroatom for the synthesis of a series of disklike Anderson-Evans clusters bearing different triol derivatives on both their faces via one-pot and/or step-by-step routes. By using a [(n-C4H9)4N]4[Mo8O26] precursor cluster and copper acetate as the starting materials, several organically modified χ isomers with Cu(II) heteroatom centers were obtained. Starting from a [(n-C4H9)4N]2[Mo2O7] subcluster, however, a half-malposition coordination fashion of triol ligands with a δ isomer on one face and a χ isomer on the other face of the Anderson-Evans cluster was obtained. By changing the reaction solvent from acetonitrile to methanol, we realized a secondary organic modification of the triol-grafted clusters and obtained a triol ligand/methanol codecoration on the Anderson-Evans polyoxometalate. In addition, by changing the reaction environment, we succeeded in modulating the transformation of triol ligands from one site to another on the polyoxometalate cluster. Importantly, by control of the reaction condition, the methanol molecules were also taken off from the cluster. PMID:27074087

  13. Abrupt physical and chemical changes during 1992-1999, Anderson Springs, SE Geyser Geothermal Field, California

    USGS Publications Warehouse

    Janik, Cathy J.; Goff, Fraser; Walter, Stephen R.; Sorey, Michael L.; Counce, Dale; Colvard, Elizabeth M.

    2000-01-01

    The Anderson Springs area is located about 90 miles (145 kilometers) north of San Francisco, California, in the southwestern part of Lake County. The area was first developed in the late 1800s as a health resort, which was active until the 1930s. Patrons drank a variety of cool to hot mineral waters from improved springs, swam in various baths and pools, and hiked in the rugged hills flanking Anderson Creek and its tributaries. In the bluffs to the south of the resort were four small mercury mines of the eastern Mayacmas quicksilver district. About 1,260 flasks of mercury were produced from these mines between 1909 and 1943. By the early 1970s, the higher ridges south and west of Anderson Springs became part of the southeast sector of the greater Geysers geothermal field. Today, several electric power plants are built on these ridges, producing energy from a vapor-dominated 240 °C reservoir. Only the main hot spring at Anderson Springs has maintained a recognizable identity since the 1930s. The hot spring is actually a cluster of seeps and springs that issue from a small fault in a ravine southwest of Anderson Creek. Published and unpublished records show that the maximum temperature (Tm) of this cluster fell gradually from 63°C in 1889 to 48°C in 1992. However, Tm of the cluster climbed to 77°C in 1995 and neared boiling (98°C) in 1998. A new cluster of boiling vents and small fumaroles (Tm = 99.3°C) formed in 1998 about 30 m north of the old spring cluster. Several evergreen trees on steep slopes immediately above these vents apparently were killed by the new activity. Thermal waters at Anderson Hot Springs are mostly composed of near-surface ground waters with some added gases and condensed steam from The Geysers geothermal system. Compared to gas samples from Southeast Geysers wells, the hot spring gases are higher in CO2 and lower in H2S and NH3. As the springs increased in temperature, however, the gas composition became more like the mean composition

  14. Electronic structure of vitamin B12 within the framework of the Haldane-Anderson impurity model

    NASA Astrophysics Data System (ADS)

    Kandemir, Zafer; Mayda, Selma; Bulut, Nejat

    2015-03-01

    We study the electronic structure of vitamin B12 (cyanocobalamine C63H88CoN14O14P) by using the framework of the multi-orbital single-impurity Haldane-Anderson model of a transition-metal impurity in a semiconductor host. Here, our purpose is to understand the many-body effects originating from the transition-metal impurity. In this approach, the cobalt 3 d orbitals are treated as the impurity states placed in a semiconductor host which consists of the rest of the molecule. The parameters of the resulting effective Haldane-Anderson model are obtained within the Hartree-Fock approximation for the electronic structure of the molecule. The quantum Monte Carlo technique is then used to calculate the one-electron and magnetic correlation functions of this effective Haldane-Anderson model for vitamin B12. We find that new states form inside the semiconductor gap due to the on-site Coulomb interaction at the impurity 3 d orbitals and that these states become the highest occupied molecular orbitals. In addition, we present results on the charge distribution and spin correlations around the Co atom. We compare the results of this approach with those obtained by the density-functional theory calculations.

  15. Anderson localization of electrons in single crystals: LixFe7Se8

    PubMed Central

    Ying, Tianping; Gu, Yueqiang; Chen, Xiao; Wang, Xinbo; Jin, Shifeng; Zhao, Linlin; Zhang, Wei; Chen, Xiaolong

    2016-01-01

    Anderson (disorder-induced) localization, proposed more than half a century ago, has inspired numerous efforts to explore the absence of wave diffusions in disordered media. However, the proposed disorder-induced metal-insulator transition (MIT), associated with the nonpropagative electron waves, has hardly been observed in three-dimensional (3D) crystalline materials, let alone single crystals. We report the observation of an MIT in centimeter-size single crystals of LixFe7Se8 induced by lattice disorder. Both specific heat and infrared reflectance measurements reveal the presence of considerable electronic states in the vicinity of the Fermi level when the MIT occurs, suggesting that the transition is not due to Coulomb repulsion mechanism. The 3D variable range hopping regime evidenced by electrical transport measurements at low temperatures indicates the localized nature of the electronic states on the Fermi level. Quantitative analyses of carrier concentration, carrier mobility, and simulated density of states (DOS) fully support that LixFe7Se8 is an Anderson insulator. On the basis of these results, we provide a unified DOS picture to explain all the experimental results, and a schematic diagram for finding other potential Anderson insulators. This material will thus serve as a rich playground for both theoretical and experimental investigations on MITs and disorder-induced phenomena. PMID:26989781

  16. 10 CFR 8.2 - Interpretation of Price-Anderson Act, section 170 of the Atomic Energy Act of 1954.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Interpretation of Price-Anderson Act, section 170 of the Atomic Energy Act of 1954. 8.2 Section 8.2 Energy NUCLEAR REGULATORY COMMISSION INTERPRETATIONS § 8.2 Interpretation of Price-Anderson Act, section 170 of the Atomic Energy Act of 1954. (a) It is my opinion that an indemnity agreement entered into...

  17. Thermochemical cycles

    NASA Technical Reports Server (NTRS)

    Funk, J. E.; Soliman, M. A.; Carty, R. H.; Conger, W. L.; Cox, K. E.; Lawson, D.

    1975-01-01

    The thermochemical production of hydrogen is described along with the HYDRGN computer program which attempts to rate the various thermochemical cycles. Specific thermochemical cycles discussed include: iron sulfur cycle; iron chloride cycle; and hybrid sulfuric acid cycle.

  18. SHORTER MENSTRUAL CYCLES ASSOCIATED WITH CHLORINATION BY-PRODUCTS IN DRINKING WATER

    EPA Science Inventory

    Shorter Menstrual Cycles Associated with Chlorination by-Products in Drinking Water.
    Gayle Windham, Kirsten Waller, Meredith Anderson, Laura Fenster, Pauline Mendola, Shanna Swan. California Department of Health Services.

    In previous studies of tap water consumption we...

  19. CHLORINATION BY-PRODUCTS IN DRINKING WATER AND MENSTRUAL CYCLE FUNCTION

    EPA Science Inventory

    Chlorination by-Products in Drinking Water and Menstrual Cycle Function

    Gayle C. Windham1, Kirsten Waller2, Meredith Anderson2, Laura Fenster1, Pauline Mendola3, Shanna Swan4

    1California Department of Health Services, Division of Environmental and Occupational Disea...

  20. Investigation of Anderson lattice behavior in Yb1-xLuxAl3

    SciTech Connect

    Bauer, E.D.; Booth, C.H.; Lawrence, J.M.; Hundley, M.F.; Sarrao, J.L.; Thompson, J.D.; Riseborough, P.S.; Ebihara, T.

    2003-10-06

    Measurements of magnetic susceptibility {chi}(T), specific heat C(T), Hall coefficient R{sub H}(T), and Yb valence {nu} = 2 + n{sub f} [f-occupation number n{sub f} (T) determined from Yb L{sub 3} x-ray absorption measurements] were carried out on single crystals of Yb{sub 1-x}Lu{sub x}Al{sub 3}. The low temperature anomalies observed in {chi}(T) and C(T) corresponding to an energy scale T{sub coh} {approx} 40 K in the intermediate valence, Kondo lattice compound YbAl{sub 3} are suppressed by Lu concentrations as small as 5% suggesting these low-T anomalies are extremely sensitive to disorder and, therefore, are a true coherence effect. By comparing the temperature dependence of various physical quantities to the predictions of the Anderson Impurity Model, the slow crossover behavior observed in YbAl{sub 3}, in which the data evolve from a low-temperature coherent, Fermi-liquid regime to a high temperature local moment regime more gradually than predicted by the Anderson Impurity Model, appears to evolve to fast crossover behavior at x {approx} 0.7 where the evolution is more rapid than predicted. These two phenomena found in Yb{sub 1-x}Lu{sub x}Al{sub 3}, i.e., the low-T anomalies and the slow/fast crossover behavior are discussed in relation to recent theories of the Anderson lattice.

  1. Causation's nuclear future: applying proportional liability to the Price-Anderson Act.

    PubMed

    O'Connell, William D

    2014-11-01

    For more than a quarter century, public discourse has pushed the nuclear-power industry in the direction of heavier regulation and greater scrutiny, effectively halting construction of new reactors. By focusing on contemporary fear of significant accidents, such discourse begs the question of what the nation's court system would actually do should a major nuclear incident cause radiation-induced cancers. Congress's attempt to answer that question is the Price-Anderson Act, a broad statute addressing claims by the victims of a major nuclear accident. Lower courts interpreting the Act have repeatedly encountered a major stumbling block: it declares that judges must apply the antediluvian preponderance-of-the-evidence logic of state tort law, even though radiation science insists that the causes of radiation-induced cancers are more complex. After a major nuclear accident, the Act's paradoxically outdated rules for adjudicating "causation" would make post-incident compensation unworkable. This Note urges that nuclear-power-plant liability should not turn on eighteenth-century tort law. Drawing on modern scientific conclusions regarding the invariably "statistical" nature of cancer, this Note suggests a unitary federal standard for the Price-Anderson Act--that a defendant be deemed to have "caused" a plaintiff's injury in direct proportion to the increased risk of harm the defendant has imposed. This "proportional liability" rule would not only fairly evaluate the costs borne by injured plaintiffs and protect a reawakening nuclear industry from the prospect of bank-breaking litigation, but would prove workable with only minor changes to the Price-Anderson Act's standards of "injury" and "fault." PMID:25507406

  2. Causation's nuclear future: applying proportional liability to the Price-Anderson Act.

    PubMed

    O'Connell, William D

    2014-11-01

    For more than a quarter century, public discourse has pushed the nuclear-power industry in the direction of heavier regulation and greater scrutiny, effectively halting construction of new reactors. By focusing on contemporary fear of significant accidents, such discourse begs the question of what the nation's court system would actually do should a major nuclear incident cause radiation-induced cancers. Congress's attempt to answer that question is the Price-Anderson Act, a broad statute addressing claims by the victims of a major nuclear accident. Lower courts interpreting the Act have repeatedly encountered a major stumbling block: it declares that judges must apply the antediluvian preponderance-of-the-evidence logic of state tort law, even though radiation science insists that the causes of radiation-induced cancers are more complex. After a major nuclear accident, the Act's paradoxically outdated rules for adjudicating "causation" would make post-incident compensation unworkable. This Note urges that nuclear-power-plant liability should not turn on eighteenth-century tort law. Drawing on modern scientific conclusions regarding the invariably "statistical" nature of cancer, this Note suggests a unitary federal standard for the Price-Anderson Act--that a defendant be deemed to have "caused" a plaintiff's injury in direct proportion to the increased risk of harm the defendant has imposed. This "proportional liability" rule would not only fairly evaluate the costs borne by injured plaintiffs and protect a reawakening nuclear industry from the prospect of bank-breaking litigation, but would prove workable with only minor changes to the Price-Anderson Act's standards of "injury" and "fault." PMID:25423683

  3. Data Center Energy Efficiency and Renewable Energy Site Assessment: Anderson Readiness Center; Salem, Oregon

    SciTech Connect

    Metzger, I.; Van Geet, O.

    2014-06-01

    This report summarizes the results from the data center energy efficiency and renewable energy site assessment conducted for the Oregon Army National Guard in Salem, Oregon. A team led by NREL conducted the assessment of the Anderson Readiness Center data centers March 18-20, 2014 as part of ongoing efforts to reduce energy use and incorporate renewable energy technologies where feasible. Although the data centers in this facility account for less than 5% of the total square footage, they are estimated to be responsible for 70% of the annual electricity consumption.

  4. STS-118 Astronaut Williams and Expedition 15 Engineer Anderson Perform EVA

    NASA Technical Reports Server (NTRS)

    2007-01-01

    As the construction continued on the International Space Station (ISS), STS-118 Astronaut Dave Williams, representing the Canadian Space Agency, participated in the fourth and final session of Extra Vehicular Activity (EVA). During the 5 hour space walk, Williams and Expedition 15 engineer Clay Anderson (out of frame) installed the External Wireless Instrumentation System Antenna, attached a stand for the shuttle robotic arm extension boom, and retrieved the two Materials International Space Station Experiments (MISSE) for return to Earth. MISSE collects information on how different materials weather in the environment of space.

  5. Machine learning for many-body physics: The case of the Anderson impurity model

    NASA Astrophysics Data System (ADS)

    Arsenault, Louis-François; Lopez-Bezanilla, Alejandro; von Lilienfeld, O. Anatole; Millis, Andrew J.

    2014-10-01

    Machine learning methods are applied to finding the Green's function of the Anderson impurity model, a basic model system of quantum many-body condensed-matter physics. Different methods of parametrizing the Green's function are investigated; a representation in terms of Legendre polynomials is found to be superior due to its limited number of coefficients and its applicability to state of the art methods of solution. The dependence of the errors on the size of the training set is determined. The results indicate that a machine learning approach to dynamical mean-field theory may be feasible.

  6. Anomalous Floquet-Anderson Insulator as a Nonadiabatic Quantized Charge Pump

    NASA Astrophysics Data System (ADS)

    Titum, Paraj; Berg, Erez; Rudner, Mark S.; Refael, Gil; Lindner, Netanel H.

    2016-04-01

    We show that two-dimensional periodically driven quantum systems with spatial disorder admit a unique topological phase, which we call the anomalous Floquet-Anderson insulator (AFAI). The AFAI is characterized by a quasienergy spectrum featuring chiral edge modes coexisting with a fully localized bulk. Such a spectrum is impossible for a time-independent, local Hamiltonian. These unique characteristics of the AFAI give rise to a new topologically protected nonequilibrium transport phenomenon: quantized, yet nonadiabatic, charge pumping. We identify the topological invariants that distinguish the AFAI from a trivial, fully localized phase, and show that the two phases are separated by a phase transition.

  7. Exponential Scaling Limit of the Single-Particle Anderson Model Via Adaptive Feedback Scaling

    NASA Astrophysics Data System (ADS)

    Chulaevsky, Victor

    2016-02-01

    We propose a twofold extension of the Germinet-Klein bootstrap multi-scale analysis (BMSA) for the Anderson models on graphs. First, we show, with the help of a single scaling algorithm, that power-law decay bounds at some initial scale imply an asymptotically exponential decay of eigenfunctions (EFs) and of EF correlators (EFCs), even on graphs (of polynomial growth) which do not fulfill the uniform scalability condition required for the existing BMSA techniques. We also show that the exponential scaling limit of the EFs and EFCs holds true for a class of marginal distributions of the random potential with regularity lower than Hölder continuity of any positive order.

  8. Large thermoelectric figure of merit for three-dimensional topological Anderson insulators via line dislocation engineering

    NASA Astrophysics Data System (ADS)

    Tretiakov, O. A.; Abanov, Ar.; Murakami, Shuichi; Sinova, Jairo

    2010-08-01

    We study the thermoelectric properties of three-dimensional topological Anderson insulators with line dislocations. We show that at high densities of dislocations the thermoelectric figure of merit ZT can be dominated by one-dimensional topologically protected conducting states channeled through the lattice screw dislocations in the topological insulator materials with a nonzero time-reversal-invariant momentum such as Bi0.9Sb0.1. When the chemical potential does not exceed much the mobility edge the ZT at room temperatures can reach large values, much higher than unity for reasonable parameters, hence making this system a strong candidate for applications in heat management of nanodevices.

  9. Anderson transition in low-dimensional disordered systems driven by long-range nonrandom hopping.

    PubMed

    Rodríguez, A; Malyshev, V A; Sierra, G; Martín-Delgado, M A; Rodríguez-Laguna, J; Domínguez-Adame, F

    2003-01-17

    The single-parameter scaling hypothesis predicts the absence of delocalized states for noninteracting quasiparticles in low-dimensional disordered systems. We show analytically, using a supersymmetric method combined with a renormalization group analysis, as well as numerically that extended states may occur in the one- and two-dimensional Anderson model with a nonrandom hopping falling off as some power of the distance between sites. The different size scaling of the bare level spacing and the renormalized magnitude of the disorder seen by the quasiparticles finally results in the delocalization of states at one of the band edges of the quasiparticle energy spectrum. PMID:12570579

  10. Volume dependence of Anderson hybridization in cubic CeCd and CeAg

    SciTech Connect

    Monachesi, P. ); Andreani, L.C. ); Continenza, A. ); McMahan, A.K. )

    1993-05-15

    We have undertaken a first-principles theoretical study of the Anderson hybridization in cubic CeCd and CeAg as a function of volume reduction. We present results for the hybridization width [Delta]([epsilon]) in both the [ital J]=5/2 multiplet and in the [Gamma][sub 8], [Gamma][sub 7] crystal field states of the [ital f][sup 1] Ce configuration. We also calculate the hybridization contribution to the magnetic transition temperature. This is found to increase with pressure but is smaller than the experimental values, indicating that the Coulomb exchange contribution to the magnetic coupling is not negligible in these compounds.

  11. Volume dependence of Anderson hybridization in cubic CeCd and CeAg

    SciTech Connect

    Monachesi, P.; Continenza, A. . Dipt. di Fisica); Andreani, L.C. ); McMahan, A.K. )

    1992-09-01

    We have undertaken a first-principles theoretical study of the Anderson hybridization in cubic CeCd and CeAg as a function of volume reduction. We present results for the hybridization width [Delta]([epsilon]) in both the J = 5/2 multiplet and in the [Gamma][sub 8], [Gamma][sub 7] crystal field states of the f[sup 1] Ce configuration. We also calculate the hybridization contribution to the magnetic transition temperature. This is found to increase with pressure but is smaller than the experimental values, indicating that the Coulomb exchange contribution to the magnetic coupling is not negligible in these compounds.

  12. Volume dependence of Anderson hybridization in cubic CeCd and CeAg

    SciTech Connect

    Monachesi, P.; Continenza, A.; Andreani, L.C.; McMahan, A.K.

    1992-09-01

    We have undertaken a first-principles theoretical study of the Anderson hybridization in cubic CeCd and CeAg as a function of volume reduction. We present results for the hybridization width {Delta}({epsilon}) in both the J = 5/2 multiplet and in the {Gamma}{sub 8}, {Gamma}{sub 7} crystal field states of the f{sup 1} Ce configuration. We also calculate the hybridization contribution to the magnetic transition temperature. This is found to increase with pressure but is smaller than the experimental values, indicating that the Coulomb exchange contribution to the magnetic coupling is not negligible in these compounds.

  13. ASCOT data from the 1980 field measurement program in the Anderson Creek Valley, California. Vol. II

    SciTech Connect

    Gudiksen, P.H.

    1983-04-01

    This report provides a listing of the data acquired during a series of nocturnal drainage flow experiments that were conducted by ASCOT participants in the Anderson Creek valley during September 1980. These experiments were designed to evaluate the transport and dispersion characteristics associated with nocturnal drainage flows. The report includes data from meteorological measurements systems and tracer experiments. The meteorological data include measurements from tethersondes, acoustic sounders, meteorological towers, pilot balloons, optical anemometers, and rawinsondes; while the tracer experiments provided data on the spatial and temporal distributions of perfluorocarbon, heavy methane, sulfur hexafluoride, oil fog, tetroons, and radon tracers.

  14. ASCOT data from the 1980 field measurement program in the Anderson Creek Valley, California. Vol. III

    SciTech Connect

    Gudiksen, P.H.

    1983-04-01

    This report provides a listing of the data acquired during a series of nocturnal drainage flow experiments that were conducted by ASCOT participants in the Anderson Creek valley during September 1980. These experiments were designed to evaluate the transport and dispersion characteristics associated with nocturnal drainage flows. The report includes data from meteorological measurements systems and tracer experiments. The meteorological data include measurements from tethersondes, acoustic sounders, meteorological towers, pilot balloons, optical anemometers, and rawinsondes, while the tracer experiments provided data on the spatial and temporal distributions of perfluorocarbon, heavy methane, sulfur hexafluoride, oil fog, tetroons, and radon tracers.

  15. Physical, chemical, and isotopic data for samples from the Anderson Springs area, Lake County, California, 1998-1999

    USGS Publications Warehouse

    Janik, C.J.; Goff, F.; Sorey, M.L.; Rytuba, J.J.; Counce, D.; Colvard, E.M.; Huebner, M.; White, L.D.; Foster, A.

    1999-01-01

    Anderson Springs is located about 90 miles (145 kilometers) north of San Francisco, California, in the southwestern part of Lake County. The area was first developed in the late 1800s as a health resort, which was active until the 1930s. In the rugged hills to the south of the resort were four small mercury mines of the eastern Mayacmas quicksilver district. About 1,260 flasks of mercury were produced from these mines between 1909 and 1943. In the 1970s, the high-elevation areas surrounding Anderson Springs became part of The Geysers geothermal field. Today, several electric powerplants are located on the ridges above Anderson Springs, utilizing steam produced from a 240°C vapor-dominated reservoir. The primary purpose of this report is to provide physical, chemical, and isotopic data on samples collected in the Anderson Springs area during 1998 and 1999, in response to a Freedom of Information Act request. In July 1998, drainage from the Schwartz adit of the abandoned Anderson mercury mine increased substantially over a 2-day period, transporting a slurry of water and precipitates down a tributary and into Anderson Creek. In August 1998, J.J. Rytuba and coworkers sampled the Schwartz adit drainage and water from the Anderson Springs Hot Spring for base metal and methylmercury analysis. They measured a maximum temperature (Tm) of 85°C in the Hot Spring. Published records show that the temperature of the Anderson Springs Hot Spring (main spring) was 63°C in 1889, 42–52°C from 1974 through 1991, and 77°C in March 1995. To investigate possible changes in thermal spring activity and to collect additional samples for geochemical analysis, C.J. Janik and coworkers returned to the area in September and December 1998. They determined that a cluster of springs adjacent to the main spring had Tm=98°C, and they observed that a new area of boiling vents and small fumaroles (Tm=99.3°C) had formed in an adjacent gully about 20 meters to the north of the main spring

  16. The atomic approach to the Anderson model for the finite U case: application to a quantum dot.

    PubMed

    Lobo, T; Figueira, M S; Foglio, M E

    2010-07-01

    In the present work we apply the atomic approach to the single-impurity Anderson model (SIAM). A general formulation of this approach, that can be applied both to the impurity and to the lattice Anderson Hamiltonian, was developed in a previous work (Foglio et al 2009 arxiv: 0903.0139v2 [cond-mat.str-el]). The method starts from the cumulant expansion of the periodic Anderson model, employing the hybridization as a perturbation. The atomic Anderson limit is analytically solved and its sixteen eigenenergies and eigenstates are obtained. This atomic Anderson solution, which we call the AAS, has all the fundamental excitations that generate the Kondo effect, and in the atomic approach is employed as a 'seed' to generate the approximate solutions for finite U. The width of the conduction band is reduced to zero in the AAS, and we choose its position such that the Friedel sum rule is satisfied, close to the chemical potential mu. We perform a complete study of the density of states of the SIAM over the whole relevant range of parameters: the empty dot, intermediate valence, Kondo and magnetic regimes. In the Kondo regime we obtain a density of states that characterizes well the structure of the Kondo peak. To show the usefulness of the method we have calculated the conductance of a quantum dot, side-coupled to a conduction band. PMID:20571194

  17. The Wyodak-Anderson coal assessment, Powder River Basin, Wyoming and Montana -- An ArcView project

    SciTech Connect

    Flores, R.M.; Gunther, G.; Ochs, A.; Ellis, M.E.; Stricker, G.D.; Bader, L.R.

    1998-12-31

    In 1997, more than 305 million short tons of clean and compliant coal were produced from the Wyodak-Anderson and associated coal beds and zones of the Paleocene Fort Union Formation in the Powder River Basin, Wyoming and Montana. To date, all coal produced from the Wyodak-Anderson, which averages 0.47 percent sulfur and 6.44 percent ash, has met regulatory compliance standards. Twenty-eight percent of the total US coal production in 1997 was from the Wyodak-Anderson coal. Based on the current consumption rates and forecast by the Energy Information Administration (1996), the Wyodak-Anderson coal is projected to produce 413 million short tons by the year 2016. In addition, this coal deposit as well as other Fort Union coals have recently been targeted for exploration and development of methane gas. New US Geological Survey (USGS) digital products could provide valuable assistance in future mining and gas development in the Powder River Basin. An interactive format, with querying tools, using ArcView software will display the digital products of the resource assessment of Wyodak-Anderson coal, a part of the USGS National Coal Resource Assessment of the Powder River Basin. This ArcView project includes coverages of the data point distribution; land use; surface and subsurface ownerships; coal geology, stratigraphy, quality and geochemistry; and preliminary coal resource calculations. These coverages are displayed as map views, cross sections, tables, and charts.

  18. Simulation of Anderson localization in two-dimensional ultracold gases for pointlike disorder

    NASA Astrophysics Data System (ADS)

    Morong, W.; DeMarco, B.

    2015-08-01

    Anderson localization has been observed for a variety of media, including ultracold atomic gases with speckle disorder in one and three dimensions. However, observation of Anderson localization in a two-dimensional geometry for ultracold gases has been elusive. We show that a cause of this difficulty is the relatively high percolation threshold of a speckle potential in two dimensions, resulting in strong classical localization. We propose a realistic pointlike disorder potential that circumvents this percolation limit with localization lengths that are experimentally observable. The percolation threshold is evaluated for experimentally realistic parameters, and a regime of negligible classical trapping is identified. Localization lengths are determined via scaling theory, using both exact scattering cross sections and the Born approximation, and by direct simulation of the time-dependent Schrödinger equation. We show that the Born approximation can underestimate the localization length by four orders of magnitude at low energies, while exact cross sections and scaling theory provide an upper bound. Achievable experimental parameters for observing localization in this system are proposed.

  19. Finite size effect and Friedel oscillations for a Friedel-Anderson impurity by FAIR method

    NASA Astrophysics Data System (ADS)

    Tao, Yaqi

    A compact solution consisting of 4-8 Slater states (FAIR solution) is introduced to treat the Friedel Anderson and Kondo impurity problem. The ground state energy is obtained with impressively high accuracy. Net integrated polarization density is calculated and it confirms the existence of Kondo cloud. Finite size effect in the impurity problem is studied using FAIR method. It is shown that the formation of a Kondo ground state requires a minimum sample size and is accompanied by the presence of Kondo cloud. The Friedel Oscillations in the vicinity of a Friedel-Anderson impurity are investigated by FAIR method. The development of Friedel oscillation with a phase shift of pi/2 outside the Kondo radius is confirmed. And the amplitude A(xi) of the Friedel oscillations show a very similar behavior to that of a simple non-interacting Friedel impurity with a narrow resonance at the Fermi level. This similarity supports the concept of a "Kondo" resonance. And the Kondo resonance half width GammaFA is suggested to be GammaFA ≈ Echi/2.4, where Echi is the Kondo energy calculated from susceptibility.

  20. Dr Walter Henry Anderson (1870-1937) and the mission hospital at Safed, Palestine.

    PubMed

    Stokes, Gordon S

    2013-02-01

    Walter Henry Anderson, a brewer's clerk in Burton-upon-Trent, became a missionary doctor, supported by a society promoting welfare and evangelism in Jewish communities abroad. His family background was rich in pastoral ministry at home and adventure abroad. Arguably, this background played a part in his decision to serve the Jews of Safed. His life in Palestine entailed much enterprise and hardship as he raised a family, fought disease and set up a mission hospital serving not only the Jewish community but persons of all faiths. His years in Palestine, from 1894 to 1915, were times of peace in the Middle East before the turmoil unleashed by the Great War. Jews from the Diaspora were gaining an increasing foothold in Palestine, their 'Promised Land'. Themes of that era - the rise of Zionism, confrontation between Judaism and evangelical Christianity, conflict between immigrant Jew and Palestinian Arab and the remarkable travels of Lawrence of Arabia were interwoven with the lives of Dr Anderson and his family. PMID:23610230

  1. Electronic structure and correlations of vitamin B12 studied within the Haldane-Anderson impurity model

    NASA Astrophysics Data System (ADS)

    Kandemir, Zafer; Mayda, Selma; Bulut, Nejat

    2016-05-01

    We study the electronic structure and correlations of vitamin B12 (cyanocobalamine) by using the framework of the multi-orbital single-impurity Haldane-Anderson model of a transition-metal impurity in a semiconductor host. The parameters of the effective Haldane-Anderson model are obtained within the Hartree-Fock (HF) approximation. The quantum Monte Carlo (QMC) technique is then used to calculate the one-electron and magnetic correlation functions of this effective model. We observe that new states form inside the semiconductor gap found by HF due to the intra-orbital Coulomb interaction at the impurity 3 d orbitals. In particular, the lowest unoccupied states correspond to an impurity bound state, which consists of states from mainly the CN axial ligand and the corrin ring as well as the Co e g -like orbitals. We also observe that the Co (3 d) orbitals can develop antiferromagnetic correlations with the surrounding atoms depending on the filling of the impurity bound states. In addition, we make comparisons of the HF+QMC data with the density functional theory calculations. We also discuss the photoabsorption spectrum of cyanocobalamine.

  2. Analysis of Anderson Acceleration on a Simplified Neutronics/Thermal Hydraulics System

    SciTech Connect

    Toth, Alex; Kelley, C. T.; Slattery, Stuart R; Hamilton, Steven P; Clarno, Kevin T; Pawlowski, R. P. P.

    2015-01-01

    ABSTRACT A standard method for solving coupled multiphysics problems in light water reactors is Picard iteration, which sequentially alternates between solving single physics applications. This solution approach is appealing due to simplicity of implementation and the ability to leverage existing software packages to accurately solve single physics applications. However, there are several drawbacks in the convergence behavior of this method; namely slow convergence and the necessity of heuristically chosen damping factors to achieve convergence in many cases. Anderson acceleration is a method that has been seen to be more robust and fast converging than Picard iteration for many problems, without significantly higher cost per iteration or complexity of implementation, though its effectiveness in the context of multiphysics coupling is not well explored. In this work, we develop a one-dimensional model simulating the coupling between the neutron distribution and fuel and coolant properties in a single fuel pin. We show that this model generally captures the convergence issues noted in Picard iterations which couple high-fidelity physics codes. We then use this model to gauge potential improvements with regard to rate of convergence and robustness from utilizing Anderson acceleration as an alternative to Picard iteration.

  3. Time-dependent Mott transition in the periodic Anderson model with nonlocal hybridization

    NASA Astrophysics Data System (ADS)

    Hofmann, Felix; Potthoff, Michael

    2016-08-01

    The time-dependent Mott transition in a periodic Anderson model with off-site, nearest-neighbor hybridization is studied within the framework of nonequilibrium self-energy functional theory. Using the two-site dynamical-impurity approximation, we compute the real-time dynamics of the optimal variational parameter and of different observables initiated by sudden quenches of the Hubbard-U and identify the critical interaction. The time-dependent transition is orbital selective, i.e., in the final state, reached in the long-time limit after the quench to the critical interaction, the Mott gap opens in the spectral function of the localized orbitals only. We discuss the dependence of the critical interaction and of the final-state effective temperature on the hybridization strength and point out the various similarities between the nonequilibrium and the equilibrium Mott transition. It is shown that these can also be smoothly connected to each other by increasing the duration of a U-ramp from a sudden quench to a quasi-static process. The physics found for the model with off-site hybridization is compared with the dynamical Mott transition in the single-orbital Hubbard model and with the dynamical crossover found for the real-time dynamics of the conventional Anderson lattice with on-site hybridization.

  4. Gutzwiller approach to the Anderson lattice model with no orbital degeneracy

    NASA Astrophysics Data System (ADS)

    Vulović, Vladimir Z.; Abrahams, Elihu

    1987-08-01

    A new technique is used to obtain the Gutzwiller ground-state energy functional for the Anderson lattice model with no orbital degeneracy (ALM). For the Hubbard model, known expressions are derived with ease and simplicity. For the ALM, we derive the ground-state energy functional of Varma, Weber, and Randall. As a check on our Gutzwiller functional, we find an independent analytical upper bound for the ground-state energy of ALM with a dispersionless f band. For the case of a dispersionless f band and momentum-independent hybridization, in the Kondo regime, we derive analytical expressions for the ground-state energy, charge, and magnetic susceptibilities. For the special case of infinite Coulomb repulsion, we recover results of Rice and Ueda and of Fazekas and Brandow, notably the negative value of the magnetic susceptibility. The negative magnetic susceptibility persists in the entire Kondo region, i.e., finite-U effects do not stabilize the nonmagnetic Kondo state. This suggests that nonzero orbital degeneracy in the Anderson lattice model must be retained to describe heavy-fermion materials with a normal Fermi liquid ground state.

  5. Electronic structure and correlations of vitamin B12 studied within the Haldane-Anderson impurity model

    NASA Astrophysics Data System (ADS)

    Kandemir, Zafer; Mayda, Selma; Bulut, Nejat

    2016-04-01

    We study the electronic structure and correlations of vitamin B12 (cyanocobalamine) by using the framework of the multi-orbital single-impurity Haldane-Anderson model of a transition-metal impurity in a semiconductor host. The parameters of the effective Haldane-Anderson model are obtained within the Hartree-Fock (HF) approximation. The quantum Monte Carlo (QMC) technique is then used to calculate the one-electron and magnetic correlation functions of this effective model. We observe that new states form inside the semiconductor gap found by HF due to the intra-orbital Coulomb interaction at the impurity 3d orbitals. In particular, the lowest unoccupied states correspond to an impurity bound state, which consists of states from mainly the CN axial ligand and the corrin ring as well as the Co eg-like orbitals. We also observe that the Co (3d) orbitals can develop antiferromagnetic correlations with the surrounding atoms depending on the filling of the impurity bound states. In addition, we make comparisons of the HF+QMC data with the density functional theory calculations. We also discuss the photoabsorption spectrum of cyanocobalamine.

  6. Patriot Games: Yes, Indeed, the British Are Coming! But M. T. Anderson's Revolutionary War Novel Is Unlike Anything You've Ever Read

    ERIC Educational Resources Information Center

    Horning, Kathleen

    2006-01-01

    This article presents an interview with 38-year-old writer Matthew Tobin Anderson. In the interview, Anderson talks about his experiences, passion for writing, teenage interests, and his relation to the distinguished writer Mark Twain. He also states the importance of liberty and what it takes to be a patriot and a loyalist. Furthermore, Matthew…

  7. Reduced Basis Methods for the One Over N Expansion of the Anderson Model

    NASA Astrophysics Data System (ADS)

    Landgraf, Jeffery Michael

    1995-01-01

    The Anderson model simultaneously explains both the bulk properties and valence photoemission spectrum of Cerium and Ytterbium heavy fermion materials. The observed spectral properties of Uranium heavy fermion compounds, however, are qualitatively different; They show a single bandlike peak near the Fermi energy rather than multiple ionization peaks. The spectral properties of Uranium heavy fermion systems represent an unanswered challenge for the description of heavy fermions using the Anderson model. We investigate this issue using an f^1 - f^2 Anderson model and the zero temperature 1/N expansion. The Kondo temperature is small for all valences which is consistent with heavy fermion behavior even in the mixed valence region. In this region, the calculated photoemission spectrum has a Fermi energy peak which contains substantial spectral weight. Unfortunately, the peak is much more narrow than observed in Uranium systems. Spin-orbit effects may broaden the low energy peak. We include Hunds first rule splitting for the f ^2 state in photoemission calculation. The spectrum then has additional structure at low energies, but the overall weight added is too small to explain observed spectra without considering extra broadening mechanisms, such as additional spin orbit terms. We also make contributions to the formal theory of the 1/N expansion. We present a diagrammatic scheme for classifying the basis elements and their coupling, from which the wave function equations may be directly obtained. Secondly, we develop a formulation of the 1/N expansion based upon zeroing the O(Gamma/N) coupling between basis elements with different numbers of electron-hole pairs. The Hamiltonian is then block diagonal. We obtain a full eigenstate and eigenvalue spectrum which is similar to that of the leading order ground state basis replicated at higher energies. Finally we undertake a systematic study of the 1/N corrections for the f^1 - f^2 model. We directly calculate first order

  8. Large Disorder Renormalization Group Study of the Anderson Model of Localization

    NASA Astrophysics Data System (ADS)

    Johri, Sonika; Bhatt, R. N.

    2015-03-01

    We describe a large disorder renormalization group (LDRG) scheme for the Anderson model of localization in one dimension which eliminates eigenstates based on the size of their wavefunctions rather than their energy (as done in RG models to date). We show that our LDRG scheme flows to infinite disorder, and thus becomes asymptotically exact. We use it to obtain the disorder-averaged inverse participation ratio and density of states and compare these with results obtained by exact numerical diagonalization for the entire spectrum. A modified method is formulated for higher dimensions, which is found to be less efficient, but capable of improvement. The possibility of extending this scheme to many-body localized states will be discussed. This work was supported by Department of Energy Grant No. DE-SC0002140.

  9. Interpretation of high-dimensional numerical results for the Anderson transition

    SciTech Connect

    Suslov, I. M.

    2014-12-15

    The existence of the upper critical dimension d{sub c2} = 4 for the Anderson transition is a rigorous consequence of the Bogoliubov theorem on renormalizability of φ{sup 4} theory. For d ≥ 4 dimensions, one-parameter scaling does not hold and all existent numerical data should be reinterpreted. These data are exhausted by the results for d = 4, 5 from scaling in quasi-one-dimensional systems and the results for d = 4, 5, 6 from level statistics. All these data are compatible with the theoretical scaling dependences obtained from Vollhardt and Wolfle’s self-consistent theory of localization. The widespread viewpoint that d{sub c2} = ∞ is critically discussed.

  10. High-energy neutron dosimetry at the Clinton P. Anderson Meson Physics Facility

    SciTech Connect

    Mallett, M.W.; Vasilik, D.G.; Littlejohn, G.J.; Cortez, J.R.

    1990-01-01

    Neutron energy spectrum measurements performed at the Clinton P. Anderson Meson Physics Facility indicated potential areas for high energy neutron exposure to personnel. The low sensitivity of the Los Alamos thermoluminescent dosimeter (TLD) to high energy neutrons warranted issuing a NTA dosimeter in addition to the TLD badge to employees entering these areas. The dosimeter consists of a plastic holder surrounding NTA film that has been desiccated and sealed in a dry nitrogen environment. A study of the fading of latent images in NTA film demonstrated the success of this packaging method to control the phenomenon. The Los Alamos NTA dosimeter is characterized and the fading study discussed. 10 refs., 4 figs., 2 tabs.

  11. VizieR Online Data Catalog: Radio observations of Galactic WISE HII regions (Anderson+, 2015)

    NASA Astrophysics Data System (ADS)

    Anderson, L. D.; Armentrout, W. P.; Johnstone, B. M.; Bania, T. M.; Balser, D. S.; Wenger, T. V.; Cunningham, V.

    2016-01-01

    We draw our targets from the MIR objects in the WISE catalog of Anderson+, 2014, J/ApJS/212/1. We also include in our sample Sharpless H II regions (Sharpless 1959, VII/20). See section 2 for further details. Our observations were made with the GBT 100m telescope from 2012 July through 2014 August. There are seven radio recombination lines (RRLs) that can be cleanly observed simultaneously with the GBT in the X-band: H87α to H93α. We average these seven RRLs (each at two orthogonal polarizations) to create a single average RRL spectrum. We followed the same GBT observational procedure as in the original HRDS (Green Bank Telescope H II Region Discovery Survey (GBT HRDS; Bania et al. 2010ApJ...718L.106B). (3 data files).

  12. Pu 4f XPS spectra analyzed in the Anderson impurity model

    SciTech Connect

    Cox, L.E.; Peek, J.M.; Allen, J.W.

    1998-05-09

    X-ray photoemission spectra of the {alpha},{beta},{gamma}, and {delta} phases of Pu have been analyzed using the Gunnarsson-Schonhammer implementation of the Anderson impurity model. Changes in the relative intensities of the two spectral features representing mixed f{sup 5} and f{sup 6} final states are in reasonable agreement with the model`s predictions. The coulomb terms, U{sub ff} and U{sub fc}, are quite consistent with those derived from atomic and LDA calculations. Multiplet structure, which agrees with atomic calculations for 4f{sup 13}5f{sup 5}, strongly suggests 5f localization in the final state.

  13. Anderson localization with second quantized fields in a coupled array of waveguides

    SciTech Connect

    Thompson, Clinton; Vemuri, Gautam; Agarwal, G. S.

    2010-11-15

    We report a theoretical study of Anderson localization of nonclassical light in an array of waveguides in which neighboring waveguides are evanescently coupled and in which the disorder can be added in a controlled manner. We use squeezed light at the input to investigate the effects of nonclassicality and compare the results with those obtained by using conventional classical fields, such as a coherent field and a Gaussian field. Our results show that there is an enhancement in fluctuations of localized light due to the medium's disorder. We find superbunching of the localized light, which may be useful for enhancing the interaction between radiation and matter. Another important consequence of sub-Poissonian statistics of the incoming light is to quench the total fluctuations at the output. Finally, we show that as a result of the multiplicative noise in the problem, the output field is far from Gaussian even if the input is a coherent field.

  14. Anderson-Holstein model in two flavors of the noncrossing approximation

    NASA Astrophysics Data System (ADS)

    Chen, Hsing-Ta; Cohen, Guy; Millis, Andrew J.; Reichman, David R.

    2016-05-01

    The dynamical interplay between electron-electron interactions and electron-phonon coupling is investigated within the Anderson-Holstein model, a minimal model for open quantum systems that embody these effects. The influence of phonons on spectral and transport properties is explored in equilibrium, for nonequilibrium steady state and for transient dynamics after a quench. Both the particle-hole symmetric and the more generic particle-hole asymmetric cases are studied. The treatment is based on two complementary noncrossing approximations, the first of which is constructed around the weak-coupling limit and the second around the polaron limit. In general, the two methods disagree in nontrivial ways, indicating that more reliable approaches to the problem are needed. The frameworks used here can form the starting point for numerically exact methods based on bold-line continuous-time quantum Monte Carlo algorithms capable of treating open systems simultaneously coupled to multiple fermionic and bosonic baths.

  15. Leveraging Anderson Acceleration for improved convergence of iterative solutions to transport systems

    SciTech Connect

    Willert, Jeffrey; Taitano, William T.; Knoll, Dana

    2014-09-15

    In this note we demonstrate that using Anderson Acceleration (AA) in place of a standard Picard iteration can not only increase the convergence rate but also make the iteration more robust for two transport applications. We also compare the convergence acceleration provided by AA to that provided by moment-based acceleration methods. Additionally, we demonstrate that those two acceleration methods can be used together in a nested fashion. We begin by describing the AA algorithm. At this point, we will describe two application problems, one from neutronics and one from plasma physics, on which we will apply AA. We provide computational results which highlight the benefits of using AA, namely that we can compute solutions using fewer function evaluations, larger time-steps, and achieve a more robust iteration.

  16. High-order terms in the renormalized perturbation theory for the Anderson impurity model

    NASA Astrophysics Data System (ADS)

    Pandis, Vassilis; Hewson, Alex C.

    2015-09-01

    We study the renormalized perturbation theory of the single-impurity Anderson model, particularly the high-order terms in the expansion of the self-energy in powers of the renormalized coupling U ˜. Though the presence of counterterms in the renormalized theory may appear to complicate the diagrammatics, we show how these can be seamlessly accommodated by carrying out the calculation order-by-order in terms of skeleton diagrams. We describe how the diagrams pertinent to the renormalized self-energy and four vertex can be automatically generated, translated into integrals, and numerically integrated. To maximize the efficiency of our approach we introduce a generalized k -particle/hole propagator, which is used to analytically simplify the resultant integrals and reduce the dimensionality of the integration. We present results for the self-energy and spectral density to fifth order in U ˜, for various values of the model asymmetry, and compare them to a numerical renormalization group calculation.

  17. Modified Anderson Method for Accelerating 3D-RISM Calculations Using Graphics Processing Unit.

    PubMed

    Maruyama, Yutaka; Hirata, Fumio

    2012-09-11

    A fast algorithm is proposed to solve the three-dimensional reference interaction site model (3D-RISM) theory on a graphics processing unit (GPU). 3D-RISM theory is a powerful tool for investigating biomolecular processes in solution; however, such calculations are often both memory-intensive and time-consuming. We sought to accelerate these calculations using GPUs, but to work around the problem of limited memory size in GPUs, we modified the less memory-intensive "Anderson method" to give faster convergence to 3D-RISM calculations. Using this method on a Tesla C2070 GPU, we reduced the total computational time by a factor of 8, 1.4 times by the modified Andersen method and 5.7 times by GPU, compared to calculations on an Intel Xeon machine (eight cores, 3.33 GHz) with the conventional method. PMID:26605714

  18. Competition between Hund's coupling and Kondo effect in a one-dimensional extended periodic Anderson model

    NASA Astrophysics Data System (ADS)

    Hagymási, I.; Sólyom, J.; Legeza, Ö.

    2015-07-01

    We study the ground-state properties of an extended periodic Anderson model to understand the role of Hund's coupling between localized and itinerant electrons using the density-matrix renormalization group algorithm. By calculating the von Neumann entropies we show that two phase transitions occur and two new phases appear as the hybridization is increased in the symmetric half-filled case due to the competition between Kondo effect and Hund's coupling. In the intermediate phase, which is bounded by two critical points, we found a dimerized ground state, while in the other spatially homogeneous phases the ground state is Haldane-like and Kondo-singlet-like, respectively. We also determine the entanglement spectrum and the entanglement diagram of the system by calculating the mutual information thereby clarifying the structure of each phase.

  19. Large thermoelectric figure of merit for three-dimensional topological Anderson insulators via line dislocation engineering

    NASA Astrophysics Data System (ADS)

    Tretiakov, Oleg; Abanov, Artem; Murakami, Shuichi; Sinova, Jairo

    2011-03-01

    We study the thermoelectric properties of three-dimensional topological Anderson insulators with line dislocations. We show that at high densities of dislocations the thermoelectric figure of merit ZT can be dominated by one-dimensional topologically protected conducting states channeled through the lattice screw dislocations in the topological insulator materials with a nonzero time-reversal-invariant momentum such as Bi 0.9 Sb 0.1 . When the chemical potential does not exceed much the mobility edge the ZT at room temperatures can reach large values, much higher than unity for reasonable parameters, hence making this system a strong candidate for applications in heat management of nanodevices. This work was supported by NSF under Grant Nos. DMR-0547875 and 0757992, by the Research Corporation Cottrell Scholar Award, and by the Welch Foundation (A-1678).

  20. Tunable Anderson metal-insulator transition in quantum spin-Hall insulators

    NASA Astrophysics Data System (ADS)

    Chen, Chui-Zhen; Liu, Haiwen; Jiang, Hua; Sun, Qing-feng; Wang, Ziqiang; Xie, X. C.

    2015-06-01

    We numerically study disorder effects in the Bernevig-Hughes-Zhang (BHZ) model, and we find that the Anderson transition of a quantum spin-Hall insulator (QSHI) is determined by model parameters. The BHZ Hamiltonian is equivalent to two decoupled spin blocks that belong to the unitary class. In contrast to the common belief that a two-dimensional unitary system scales to an insulator except at certain critical points, we find, through calculations scaling properties of the localization length, level statistics, and participation ratio, that a possible exotic metallic phase emerges between the QSHI and normal insulator phases in the InAs/GaSb-type BHZ model. On the other hand, direct transition from a QSHI to a normal insulator is found in the HgTe/CdTe-type BHZ model. Furthermore, we show that the metallic phase originates from the Berry phase and can survive both inside and outside the gap.

  1. Buildup of the Kondo effect from real-time effective action for the Anderson impurity model

    NASA Astrophysics Data System (ADS)

    Bock, Sebastian; Liluashvili, Alexander; Gasenzer, Thomas

    2016-07-01

    The nonequilibrium time evolution of a quantum dot is studied by means of dynamic equations for time-dependent Green's functions derived from a two-particle-irreducible (2PI) effective action for the Anderson impurity model. Coupling the dot between two leads at different voltages, the dynamics of the current through the dot is investigated. We show that the 2PI approach is capable of describing the dynamical buildup of the Kondo effect, which shows up as a sharp resonance in the spectral function, with a width exponentially suppressed in the electron self-coupling on the dot. An external voltage applied to the dot is found to deteriorate the Kondo effect at the hybridization scale. The dynamic equations are evaluated within different nonperturbative resummation schemes, within the direct, particle-particle, and particle-hole channels, as well as their combination, and the results compared with those from other methods.

  2. Financial protection against nuclear hazards: thirty years' experience under the Price-Anderson Act

    SciTech Connect

    Not Available

    1984-01-01

    Supplementing earlier reports on ways to provide financial protection against the potential hazards involved in the production of nuclear energy by analyzing the issues raised in the Silkwood v. Kerr-McGee Corporation decision, the author explores the impact of the case on the availability of funds to compensate the public and any increased exposure of the nuclear industry or the federal government to public liability. She concludes that the decision will have a significant impact on the day-to-day administration of claims, and could lead to higher premiums. The court would have to determine the priority given to claims in the event of a catastrophic accident, in which case the only significant impact would be under amendments to the Price-Anderson Act which resulted in elimination of its coverage or a substantial increase in or elimination of the limitation on liability.

  3. Information Transmission and Anderson Localization in two-dimensional networks of firing-rate neurons

    NASA Astrophysics Data System (ADS)

    Natale, Joseph; Hentschel, George

    Firing-rate networks offer a coarse model of signal propagation in the brain. Here we analyze sparse, 2D planar firing-rate networks with no synapses beyond a certain cutoff distance. Additionally, we impose Dale's Principle to ensure that each neuron makes only or inhibitory outgoing connections. Using spectral methods, we find that the number of neurons participating in excitations of the network becomes insignificant whenever the connectivity cutoff is tuned to a value near or below the average interneuron separation. Further, neural activations exceeding a certain threshold stay confined to a small region of space. This behavior is an instance of Anderson localization, a disorder-induced phase transition by which an information channel is rendered unable to transmit signals. We discuss several potential implications of localization for both local and long-range computation in the brain. This work was supported in part by Grants JSMF/ 220020321 and NSF/IOS/1208126.

  4. ARPES in strongly correlated 4f and 5f systems: Comparison to the Periodic Anderson Model

    SciTech Connect

    Arko, A.J.; Joyce, J.J.; Cox, L.E.

    1997-12-01

    The electronic structure of both Ce and U heavy fermions appears to consist of extremely narrow, nearly temperature independent bands (i.e., no spectral weight loss or transfer with temperature). A small dispersion of the f-bands above the Kondo temperature is easily measurable so that a Kondo resonance, as defined by NCA, is not evident. Preliminary results, however, indicate that the Periodic Anderson Model captures some of the essential physics. Angle-integrated resonant photoemission results on {delta}-Pu indicate a narrow 5f feature at E{sub F}, similar in width to f-states in Ce and U compounds, but differing in that cross-section behavior of the near-E{sub F} feature suggests substantial 6D admixture.

  5. Crossover from conventional to inverse indirect magnetic exchange in the depleted Anderson lattice

    NASA Astrophysics Data System (ADS)

    Aulbach, Maximilian W.; Titvinidze, Irakli; Potthoff, Michael

    2015-05-01

    We investigate the finite-temperature properties of an Anderson lattice with regularly depleted impurities. The physics of this model is ruled by two different magnetic exchange mechanisms: conventional Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction at weak hybridization strength V and an inverse indirect magnetic exchange (IIME) at strong V , both favoring a ferromagnetic ground state. The stability of ferromagnetic order against thermal fluctuations is systematically studied by static mean-field theory for an effective low-energy spin-only model emerging perturbatively in the strong-coupling limit as well as by dynamical mean-field theory for the full model. The Curie temperature is found at a maximum for a half-filled conduction band and at intermediate hybridization strengths in the crossover regime between RKKY and IIME.

  6. Conductance fluctuation of edge-disordered graphene nanoribbons: Crossover from diffusive transport to Anderson localization

    SciTech Connect

    Takashima, Kengo; Yamamoto, Takahiro

    2014-03-03

    Conductance fluctuation of edge-disordered graphene nanoribbons (ED-GNRs) is examined using the non-equilibrium Green's function technique combined with the extended Hückel approximation. The mean free path λ and the localization length ξ of the ED-GNRs are determined to classify the quantum transport regimes. In the diffusive regime where the length L{sub c} of the ED-GNRs is much longer than λ and much shorter than ξ, the conductance histogram is given by a Gaussian distribution function with universal conductance fluctuation. In the localization regime where L{sub c}≫ξ, the histogram is no longer the universal Gaussian distribution but a lognormal distribution that characterizes Anderson localization.

  7. Efficient Localization Bounds in a Continuous N-Particle Anderson Model with Long-Range Interaction

    NASA Astrophysics Data System (ADS)

    Chulaevsky, Victor

    2016-04-01

    We establish strong dynamical and exponential spectral localization for a class of multi-particle Anderson models in a Euclidean space with an alloy-type random potential and a sub-exponentially decaying interaction of infinite range. For the first time in the mathematical literature, the uniform decay bounds on the eigenfunction correlators (EFCs) at low energies are proved, in the multi-particle continuous configuration space, in the (symmetrized) norm-distance, which is a natural distance in the multi-particle configuration space, and not in the Hausdorff distance. This results in uniform bounds on the EFCs in arbitrarily large but bounded domains in the physical configuration space, and not only in the actually infinite space, as in prior works on multi-particle localization in Euclidean spaces.

  8. Magnetic correlations in a periodic Anderson model with nonuniform conduction electron coordination

    NASA Astrophysics Data System (ADS)

    Hartman, N.; Chiu, W.-T.; Scalettar, R. T.

    2016-06-01

    The periodic Anderson model is widely studied to understand strong correlation physics and especially the competition of antiferromagnetism and singlet formation. In this paper we extend quantum Monte Carlo work on lattices with uniform numbers of neighbors to geometries in which the conduction electron sites can have variable coordination z . This situation is relevant both to recently discovered magnetic quasicrystals and also to magnetism in doped heavy fermion systems. Our key results are the presence of antiferromagnetic order at weak interorbital hybridization Vf d, and a delay in singlet formation to larger values of Vf d on sites with larger z . The staggered magnetization tends to be larger on sites with higher z , providing insight into the behavior to be expected in crown, dice, and CaVO lattices.

  9. One-dimensional Anderson Localization: distribution of wavefunction amplitude and phase at the band center

    SciTech Connect

    Kravtsov, V. E.; Yudson, V. I.

    2009-05-14

    The statistics of normalized wavefunctions in the one-dimensional (1d) Anderson model of localization is considered. It is shown that at any energy that corresponds to a rational filling factor f = (p/q) there is a statistical anomaly which is seen in expansion of the generating function (GF) to the order q-2 in the disorder parameter. We study in detail the principle anomaly at f = (1/2) that appears in the leading order. The transfer-matrix equation of the Fokker-Planck type with a two-dimensional internal space is derived for GF. It is shown that the zero-mode variant of this equation is integrable and a solution for the generating function is found in the thermodynamic limit.

  10. Multichannel Numerical Renormalization Group study of the Anderson Hamiltonian with multiple impurities

    NASA Astrophysics Data System (ADS)

    Stokes, James; Konik, Robert

    2014-03-01

    Using the Numerical Renormalization Group (NRG), the low energy sector of the Anderson Hamiltonian with two impurities in parallel has been previously argued to be consistent with an underscreened spin-1 Kondo effect (R. Zitko and J. Bonca, Phys. Rev. B 76, 241305 (2007); Logan et al., Phys. Rev. B 80, 125117 (2009)). Bethe Ansatz and slave boson calculations have given the ground state as a singlet (M. Kulkarni and R. M. Konik, Phys. Rev. B 83, 245121 (2011)). As an attempt to understand these differences, we have developed a modified NRG routine that takes into account the multiple channels arising from the logarithmic discretization of the Fermi sea. This could conceivably allow for more complicated screening processes suggested by the Bethe ansatz computations. Results of studies using this code for various numbers of impurities and channels will be presented and discussed in relationship to these conflicting views.

  11. Modified Anderson-Darling Test-Based Target Detector in Non-Homogenous Environments

    PubMed Central

    Li, Yang; Wei, Yinsheng; Li, Bingfei; Alterovitz, Gil

    2014-01-01

    A constant false alarm rate (CFAR) target detector in non-homogenous backgrounds is proposed. Based on K-sample Anderson-Darling (AD) tests, the method re-arranges the reference cells by merging homogenous sub-blocks surrounding the cell under test (CUT) into a new reference window to estimate the background statistics. Double partition test, clutter edge refinement and outlier elimination are used as an anti-clutter processor in the proposed Modified AD (MAD) detector. Simulation results show that the proposed MAD test based detector outperforms cell-averaging (CA) CFAR, greatest of (GO) CFAR, smallest of (SO) CFAR, order-statistic (OS) CFAR, variability index (VI) CFAR, and CUT inclusive (CI) CFAR in most non-homogenous situations. PMID:25177800

  12. Anderson localization in high temperature QCD: background configuration properties and Dirac eigenmodes

    NASA Astrophysics Data System (ADS)

    Cossu, Guido; Hashimoto, Shoji

    2016-06-01

    We investigate the properties of the background gauge field configurations that act as disorder for the Anderson localization mechanism in the Dirac spectrum of QCD at high temperatures. We compute the eigenmodes of the Möbius domain-wall fermion operator on configurations generated for the SU(3) gauge theory with two flavors of fermions, in the temperature range [0.9, 1.9]T c . We identify the source of localization of the eigenmodes with gauge configurations that are self-dual and support negative fluctuations of the Polyakov loop P L , in the high temperature sea of P L ˜ 1. The dependence of these observations on the boundary conditions of the valence operator is studied. We also investigate the spatial overlap of the left-handed and right-handed projected eigenmodes in correlation with the localization and the corresponding eigenvalue. We discuss an interpretation of the results in terms of monopole-instanton structures.

  13. Tunable Anderson Localization in Hydrogenated Graphene Based on the Electric Field Effect: First-Principles Study

    NASA Astrophysics Data System (ADS)

    Kang, Joongoo; Wei, Su-Huai

    2014-03-01

    We present a mechanism for reversible switching of the Anderson localization (AL) of electrons in hydrogenated graphene through modulation of the H coverage on graphene by external electric fields. The main idea is to exploit the unique acid-base chemistry (i.e., proton transfer reaction) between NH3 gas and hydrogenated graphene, which can be controlled by applying perpendicular electric fields. The proposed field-induced control of disorder in hydrogenated graphene not only has scientific merits in a systematic study of AL of electrons in grapheme but can also lead to new insight into the development of a new type of transistor based on reversible on/off switching of AL. Furthermore, the reversible and effective tuning of the H coverage on graphene should be useful for tailoring material properties of weakly hydrogenated graphene. This work was funded by the NREL LDRD program (DE-AC36-08GO28308).

  14. Decoherence-induced conductivity in the one-dimensional Anderson model

    SciTech Connect

    Stegmann, Thomas; Wolf, Dietrich E.; Ujsághy, Orsolya

    2014-08-20

    We study the effect of decoherence on the electron transport in the one-dimensional Anderson model by means of a statistical model [1, 2, 3, 4, 5]. In this model decoherence bonds are randomly distributed within the system, at which the electron phase is randomized completely. Afterwards, the transport quantity of interest (e.g. resistance or conductance) is ensemble averaged over the decoherence configurations. Averaging the resistance of the sample, the calculation can be performed analytically. In the thermodynamic limit, we find a decoherence-driven transition from the quantum-coherent localized regime to the Ohmic regime at a critical decoherence density, which is determined by the second-order generalized Lyapunov exponent (GLE) [4].

  15. Identification and Analysis of Learning Preferences of Mentally Ill Adults in Rehabilitative Psychosocial Therapy at the Anderson Mental Health Center.

    ERIC Educational Resources Information Center

    Newman, Michael K.

    A study identified and analyzed the learning preferences of 17 seriously and chronically mentally ill adults participating in the rehabilitative psychosocial therapy program at the Toxaway Church Site of the Anderson Mental Health Center. Staff perceived as boring and unfocused the traditional treatment approach that relied mainly upon…

  16. Oblique Axis Body Fracture: An Unstable Subtype of Anderson Type III Odontoid Fractures—Apropos of Two Cases

    PubMed Central

    Konstantinidis, Lukas; Schmal, Hagen; Helwig, Peter; Knöller, Stefan; Südkamp, Norbert; Hauschild, Oliver

    2016-01-01

    Purpose. Anderson type III odontoid fractures have traditionally been considered stable and treated conservatively. However, unstable cases with unfavorable results following conservative treatment have been reported. Methods. We present the cases of two patients who sustained minimally displaced Anderson type III fractures with a characteristic fracture pattern that we refer to as “oblique type axis body fracture.” Results. The female patients aged 90 and 72 years, respectively, were both diagnosed with minimally displaced Anderson type III fractures. Both fractures had a characteristic “oblique type” fracture pattern. The first patient was treated conservatively with cervical spine immobilization in a semirigid collar. However, gross displacement was noted at the 6-week follow-up visit. The second patient was therefore treated operatively by C1–C3/4 posterior fusion and the course was uneventful. Conclusions. Oblique type axis body fractures resemble a highly unstable subtype of Anderson type III fractures with the potential of severe secondary deformity following conservative treatment, irrespective of initial grade of displacement. The authors therefore warrant a high index of suspicion for this injury and suggest early operative stabilization. PMID:27042372

  17. 10 CFR 8.2 - Interpretation of Price-Anderson Act, section 170 of the Atomic Energy Act of 1954.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... in Nuclear Energy 75 (1959). In the testimony before the Joint Committee last year, Professor Samuel... 10 Energy 1 2011-01-01 2011-01-01 false Interpretation of Price-Anderson Act, section 170 of the Atomic Energy Act of 1954. 8.2 Section 8.2 Energy NUCLEAR REGULATORY COMMISSION INTERPRETATIONS §...

  18. Oblique Axis Body Fracture: An Unstable Subtype of Anderson Type III Odontoid Fractures-Apropos of Two Cases.

    PubMed

    Takai, Hirokazu; Konstantinidis, Lukas; Schmal, Hagen; Helwig, Peter; Knöller, Stefan; Südkamp, Norbert; Hauschild, Oliver

    2016-01-01

    Purpose. Anderson type III odontoid fractures have traditionally been considered stable and treated conservatively. However, unstable cases with unfavorable results following conservative treatment have been reported. Methods. We present the cases of two patients who sustained minimally displaced Anderson type III fractures with a characteristic fracture pattern that we refer to as "oblique type axis body fracture." Results. The female patients aged 90 and 72 years, respectively, were both diagnosed with minimally displaced Anderson type III fractures. Both fractures had a characteristic "oblique type" fracture pattern. The first patient was treated conservatively with cervical spine immobilization in a semirigid collar. However, gross displacement was noted at the 6-week follow-up visit. The second patient was therefore treated operatively by C1-C3/4 posterior fusion and the course was uneventful. Conclusions. Oblique type axis body fractures resemble a highly unstable subtype of Anderson type III fractures with the potential of severe secondary deformity following conservative treatment, irrespective of initial grade of displacement. The authors therefore warrant a high index of suspicion for this injury and suggest early operative stabilization. PMID:27042372

  19. 77 FR 72906 - Chessie Logistics Co., LLC-Acquisition and Operation Exemption-J. Emil Anderson & Son, Inc.

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-06

    ... Surface Transportation Board Chessie Logistics Co., LLC--Acquisition and Operation Exemption-- J. Emil Anderson & Son, Inc. Chessie Logistics Co., LLC (Chessie), a noncarrier, has filed a verified notice of... copy of each pleading must be served on Ariel A. Erbacher, Legal Counsel, Chessie Logistics Co.,...

  20. A novel single-side azobenzene-grafted Anderson-type polyoxometalate for recognition-induced chiral migration.

    PubMed

    Zhang, Bin; Yue, Liang; Wang, Yang; Yang, Yang; Wu, Lixin

    2014-09-25

    A three-component supramolecular hybrid system based on host-guest recognition and electrostatic interaction has been developed for a consecutive chiral transfer from an alpha-cyclodextrin to cationic dyes via the bridge of a new azobenzene-grafted Anderson-type polyoxometalate cluster. PMID:25089807

  1. Nonequilibrium dynamics of a singlet-triplet Anderson impurity near the quantum phase transition

    NASA Astrophysics Data System (ADS)

    Roura Bas, P.; Aligia, A. A.

    2010-01-01

    We study the singlet-triplet Anderson model (STAM) in which a configuration with a doublet is hybridized with another containing a singlet and a triplet, as a minimal model to describe two-level quantum dots coupled to two metallic leads in effectively a one-channel fashion. The model has a quantum phase transition which separates regions of a doublet and a singlet ground state. The limits of integer valence of the STAM (which include a model similar to the underscreened spin-1 Kondo model) are derived and used to predict the behavior of the conductance through the system on both sides of the transition, where it jumps abruptly. At a special quantum critical line, the STAM can be mapped to an infinite- U ordinary Anderson model (OAM) plus a free spin 1/2. We use this mapping to obtain the spectral densities of the STAM as a function of those of the OAM at the transition. Using the non-crossing approximation (NCA), we calculate the spectral densities and conductance through the system as a function of temperature and bias voltage, and determine the changes that take place at the quantum phase transition. The separation of the spectral density into a singlet and a triplet part allows us to shed light on the underlying physics and to explain a shoulder observed recently in the zero bias conductance as a function of temperature in transport measurements through a single fullerene molecule (Roch et al 2008 Nature 453 633). The structure with three peaks observed in nonequilibrium transport in these experiments is also explained.

  2. Fermi-liquid theory for the single-impurity Anderson model

    NASA Astrophysics Data System (ADS)

    Mora, Christophe; Moca, Cǎtǎlin Paşcu; von Delft, Jan; Zaránd, Gergely

    2015-08-01

    We generalize Nozières' Fermi-liquid theory for the low-energy behavior of the Kondo model to that of the single-impurity Anderson model. In addition to the electrons' phase shift at the Fermi energy, the low-energy Fermi-liquid theory is characterized by four Fermi-liquid parameters: the two given by Nozières that enter to first order in the excitation energy, and two additional ones that enter to second order and are needed away from particle-hole symmetry. We express all four parameters in terms of zero-temperature physical observables, namely the local charge and spin susceptibilities and their derivatives with respect to the local level position. We determine these in terms of the bare parameters of the Anderson model using Bethe ansatz and numerical renormalization group (NRG) calculations. Our low-energy Fermi-liquid theory applies throughout the crossover from the strong-coupling Kondo regime via the mixed-valence regime to the empty-orbital regime. From the Fermi-liquid theory, we determine the conductance through a quantum dot symmetrically coupled to two leads in the regime of small magnetic field, low temperature, and small bias voltage, and compute the coefficients of the ˜B2 , ˜T2 , and ˜V2 terms exactly in terms of the Fermi-liquid parameters. The coefficients of T2, V2, and B2 are found to change sign during the Kondo to empty-orbital crossover. The crossover becomes universal in the limit that the local interaction is much larger than the level width. For completeness, we also compute the shot noise and discuss the resulting Fano factor.

  3. Magnetic and thermodynamic properties of the 3-D periodic anderson lattice hamiltonian

    SciTech Connect

    Huscrot, C.; McMahan, A. K.; Pollock, E. I; Scalettar, R. T.

    1998-09-10

    Tight-binding models capture many of the qualitative features of interaction-induced effects in solids. For example, the simplest such model, the single-band Hubbard Hamiltonian, describes the Mott insulating phase which occurs in correlated systems, despite the fact that the one electron band is nominally only half-filled, as well as the tendency towards magnetic order. Both phenomena occur in the transition metal oxides. The Periodic Anderson Model (PAM) is a step towards incorporating more complex orbital structure. It contains a pair of orbitals on each site--a delocalized conduction band and a set of highly correlated, localized states. The PAM successfully describes conditions for transitions between antiferromagnetic order of the local moments and phases in which these moments are quenched into singlets paired with conduction electrons. These phenomena are central to heavy fermion systems. The pressure-induced volume collapse in Ce has also been attributed to Kondo-like quenching of the local f moments in this metal, as has been discussed in the context of the impurity Anderson Model. The authors describe Quantum Monte Carlo (QMC) calculations of the magnetic and thermodynamic properties of the PAM in three dimensions. Previous QMC studies have been reported in one and two dimensions. A focus of our attention will be on the density of states and the specific heat. The organization of this paper is as follows. They first introduce the PAM and outline some of its properties. Next, a brief presentation of the Quantum Monte Carlo, Maximum Entropy, and Hartree-Fock methods is given. They then show the equilibrium magnetic properties of the PAM, including the spin correlations between conduction and localized orbitals, and antiferromagnetic correlations in the localized band, before turning to the thermodynamics and the density of states. A concluding section describes connections of this work to the problem of the rare earth volume collapse transitions.

  4. Anderson localization of matter waves in 3D anisotropic disordered potentials

    NASA Astrophysics Data System (ADS)

    Piraud, Marie

    2016-05-01

    We study quantum transport and Anderson localization of matterwaves in 3 dimensional correlated disorder, focusing on the effects of the anisotropy. Indeed, understanding the anisotropy effects is fundamental for experiments with ultracold atoms as well as for several other systems, such as electrons in MOSFETs, light in biological medium, liquid crystals. A major challenge is to understand whether the anisotropy of the diffusion tensor is altered by the interference terms at the origin of Anderson localization. In particular, its anisotropy at the mobility edge remains to be investigated. So far, all theoretical analysis have assumed - more or less implicitly - that the anisotropy of the diffusion tensor is preserved by interference effects, and have focussed on the vanishing of diffusion as a whole. In this talk, I will start by presenting the usual description of matterwave transport in disordered medium. I will then present our method to go beyond the standard self-consistent theory, which includes in particular the full anisotropic structure of the spectral function. It thus avoids the infrared divergence of the usual self-consistent theory and, most importantly, does not make any assumption on the anisotropy of the renormalized diffusion tensor when including quantum interference terms. Using a generic model of disorder with elongated correlations, we find that the diffusion tensor is strongly affected by the quantum interference terms and that the anisotropy strongly diminishes in the vicinity of the mobility edge. Our work paves the way to further investigation with speckle potentials, which are directly relevant to ultracold-atom experiments. It will permit comparison with previous predictions for the mobility edge and shed new light on ongoing experiments in the field of ultracold atoms.

  5. Fragile cycles

    NASA Astrophysics Data System (ADS)

    Bonatti, Ch.; Díaz, L. J.

    We study diffeomorphisms f with heterodimensional cycles, that is, heteroclinic cycles associated to saddles p and q with different indices. Such a cycle is called fragile if there is no diffeomorphism close to f with a robust cycle associated to hyperbolic sets containing the continuations of p and q. We construct a codimension one submanifold of Diff(S×S) that consists of diffeomorphisms with fragile heterodimensional cycles. Our construction holds for any manifold of dimension ⩾4.

  6. Menstrual Cycle

    MedlinePlus

    ... Pregnancy This information in Spanish ( en español ) The menstrual cycle Day 1 starts with the first day of ... drop around Day 25 . This signals the next menstrual cycle to begin. The egg will break apart and ...

  7. Theoretical studies of electronic band-tail states, Anderson transition and surfaces of amorphous semiconductors

    NASA Astrophysics Data System (ADS)

    Dong, Jianjun

    In this dissertation, we study the Anderson transition within the electronic band tail states, and amorphous surfaces. The disorder induced band tail states is one of the unique character of amorphous semiconductors. Because of the proximity to the Fermi level, the nature of these band tail states is of obvious interest to theory of doping and transport. The study of amorphous solid surface is also an interesting area for theory. It is possible to have some major rearrangements near surfaces of amorphous solids (the amorphous analog of surface reconstruction), and the local bonding environment could be dramatically different from that of bulk. The study of the surfaces can also help people toward understanding the growth mechanism. First, electronic band tail states of amorphous silicon and amorphous diamond were studied based on the large (4096 atom) and realistic structural models. To solve the large tight-binding Hamiltonian matrices, we used two order N methods: the maximum entropy method for computing the total densities of states, and the modified Lanczos techniques for computing the individual energy eigenstates in the band gap regions. The DC conductivity was estimated with the Kubo formula. Next, the structural and electronic properties of the surfaces of tetrahedral amorphous carbon (ta-C) were also studied with a first-principles, local basis LDA technique. We reported two structural models made under different conditions, and examined the transition of the local bonding environment from the bulk to the surface. In the study of band tail states, we observe that Anderson (local-to-extended) transition within the band states proceeds by "cluster proliferation". We interpret the nature of band tail states in terms of a "resonant cluster model" through which one can qualitatively understand the evolution of the states from midgap toward the mobility edges. In the study of ta-C surfaces, we observe that nearly 50% surface atoms are threefold coordinated and

  8. Dual nature of localization in guiding systems with randomly corrugated boundaries: Anderson-type versus entropic

    SciTech Connect

    Tarasov, Yu.V. Shostenko, L.D.

    2015-05-15

    coexist in waveguide-like systems with randomly corrugated boundaries, specifically, the entropic localization and the one-dimensional Anderson (disorder-driven) localization. If the particular mode propagates across the rough segment ballistically, the Fabry–Pérot-type oscillations should be observed in the conductance, which are suppressed for the mode transferred in the Anderson-localized regime.

  9. Commensurability effects in one-dimensional Anderson localization: Anomalies in eigenfunction statistics

    SciTech Connect

    Kravtsov, V.E.; Yudson, V.I.

    2011-07-15

    Highlights: > Statistics of normalized eigenfunctions in one-dimensional Anderson localization at E = 0 is studied. > Moments of inverse participation ratio are calculated. > Equation for generating function is derived at E = 0. > An exact solution for generating function at E = 0 is obtained. > Relation of the generating function to the phase distribution function is established. - Abstract: The one-dimensional (1d) Anderson model (AM), i.e. a tight-binding chain with random uncorrelated on-site energies, has statistical anomalies at any rational point f=(2a)/({lambda}{sub E}) , where a is the lattice constant and {lambda}{sub E} is the de Broglie wavelength. We develop a regular approach to anomalous statistics of normalized eigenfunctions {psi}(r) at such commensurability points. The approach is based on an exact integral transfer-matrix equation for a generating function {Phi}{sub r}(u, {phi}) (u and {phi} have a meaning of the squared amplitude and phase of eigenfunctions, r is the position of the observation point). This generating function can be used to compute local statistics of eigenfunctions of 1d AM at any disorder and to address the problem of higher-order anomalies at f=p/q with q > 2. The descender of the generating function P{sub r}({phi}){identical_to}{Phi}{sub r}(u=0,{phi}) is shown to be the distribution function of phase which determines the Lyapunov exponent and the local density of states. In the leading order in the small disorder we derived a second-order partial differential equation for the r-independent ('zero-mode') component {Phi}(u, {phi}) at the E = 0 (f=1/2 ) anomaly. This equation is nonseparable in variables u and {phi}. Yet, we show that due to a hidden symmetry, it is integrable and we construct an exact solution for {Phi}(u, {phi}) explicitly in quadratures. Using this solution we computed moments I{sub m} = N< vertical bar {psi} vertical bar {sup 2m}> (m {>=} 1) for a chain of the length N {yields} {infinity} and found an

  10. DMSP Auroral Charging at Solar Cycle 24 Maximum

    NASA Technical Reports Server (NTRS)

    Chandler, Michael; Parker, Linda Neergaard; Minow, Joseph I.

    2013-01-01

    It has been well established that polar orbiting satellites can experience mild to severe auroral charging levels (on the order of a few hundred volts to few kilovolts negative frame potentials) during solar minimum conditions (Frooninckx and Sojka, 1992; Anderson and Koons, 1996; Anderson, 2012). These same studies have shown a strong reduction in charging during the rising and declining phases of the past few solar cycles with a nearly complete suppression of auroral charging at solar maximum. Recently, we have observed examples of high level charging during the recent approach to Solar Cycle 24 solar maximum conditions not unlike those reported by Frooninckx and Sojka (1992). These observations demonstrate that spacecraft operations during solar maximum cannot be considered safe from auroral charging when solar activity is low. We present a survey of auroral charging events experienced by the Defense Meteorological Satellite Program (DMSP) F16 satellite during Solar Cycle 24 maximum conditions. We summarize the auroral energetic particle environment and the conditions necessary for charging to occur in this environment, we describe how the lower than normal solar activity levels for Solar Cycle 24 maximum conditions are conducive to charging in polar orbits, and we show examples of the more extreme charging events, sometimes exceeding 1 kV, during this time period.

  11. An inventory of wetlands in the East Fork Poplar Creek floodplain, Anderson and Roane Counties, Tennessee

    SciTech Connect

    1992-12-01

    An inventory of wetlands within the floodplain of East Fork Poplar Creek (EFPC) in Anderson and Roane Counties, Tennessee was conducted during October, 1991 through May, 1992 for the US Department of Energy (DOE) by the US Army Corps of Engineers, Nashville District. About 15 miles of EFPC channel and 500 acres of its floodplain are contaminated with mercury and other contaminants released from the Y-12 Plant on the DOE Oak Ridge Reservation. The wetland inventory will serve as baseline information for DOE`s remedial action planning and National Environmental Policy Act compliance efforts related to the contamination. In order to provide broad wetland determinations beyond which future wetland definitions are unlikely to expand, the 1989 Federal Manual for Identifying And Delineating Jurisdictional Wetlands was utilized. Using the manual`s methodology in a contaminated system under the approved health and safety plan presented some unique problems, resulting in intrusive sampling for field indicators of hydric soils being accomplished separately from observation of other criteria. Beginning with wetland areas identified on National Wetland Inventory Maps, the entire floodplain was examined for presence of wetland criteria, and 17 wetlands were identified ranging from 0.01 to 2.81 acres in size. The majority of wetlands identified were sized under 1 acre. Some of the wetlands identified were not delineated on the National Wetland Inventory Maps, and much of the wetland area delineated on the maps did not meet the criteria under the 1989 manual.

  12. Slow dynamics in a two-dimensional Anderson-Hubbard model

    NASA Astrophysics Data System (ADS)

    Bar Lev, Yevgeny; Reichman, David R.

    2016-02-01

    We study the real-time dynamics of a two-dimensional Anderson-Hubbard model using nonequilibrium self-consistent perturbation theory within the second-Born approximation. When compared with exact diagonalization performed on small clusters, we demonstrate that for strong disorder this technique approaches the exact result on all available timescales, while for intermediate disorder, in the vicinity of the many-body localization transition, it produces quantitatively accurate results up to nontrivial times. Our method allows for the treatment of system sizes inaccessible by any numerically exact method and for the complete elimination of finite-size effects for the times considered. We show that for a sufficiently strong disorder the system becomes nonergodic, while for intermediate disorder strengths and for all accessible timescales transport in the system is strictly subdiffusive. We argue that these results are incompatible with a simple percolation picture, but are consistent with the heuristic random resistor network model where subdiffusion may be observed for long times until a crossover to diffusion occurs. The prediction of slow finite-time dynamics in a two-dimensional interacting and disordered system can be directly verified in future cold-atoms experiments.

  13. On one-step replica symmetry breaking in the Edwards–Anderson spin glass model

    NASA Astrophysics Data System (ADS)

    Del Ferraro, Gino; Wang, Chuang; Zhou, Hai-Jun; Aurell, Erik

    2016-07-01

    We consider a one-step replica symmetry breaking description of the Edwards–Anderson spin glass model in 2D. The ingredients of this description are a Kikuchi approximation to the free energy and a second-level statistical model built on the extremal points of the Kikuchi approximation, which are also fixed points of a generalized belief propagation (GBP) scheme. We show that a generalized free energy can be constructed where these extremal points are exponentially weighted by their Kikuchi free energy and a Parisi parameter y, and that the Kikuchi approximation of this generalized free energy leads to second-level, one-step replica symmetry breaking (1RSB), GBP equations. We then proceed analogously to the Bethe approximation case for tree-like graphs, where it has been shown that 1RSB belief propagation equations admit a survey propagation solution. We discuss when and how the one-step-replica symmetry breaking GBP equations that we obtain also allow a simpler class of solutions which can be interpreted as a class of generalized survey propagation equations for the single instance graph case.

  14. Effects of correlated hybridization in the single-impurity Anderson model

    NASA Astrophysics Data System (ADS)

    Líbero, Valter; Veiga, Rodrigo

    2013-03-01

    The development of new materials often dependents on the theoretical foundations which study the microscopic matter, i.e., the way atoms interact and create distinct configurations. Among the interesting materials, those with partially filled d or f orbitals immersed in nonmagnetic metals have been described by the Anderson model, which takes into account Coulomb correlation (U) when a local level (energy Ed) is doubled occupied, and an electronic hybridization between local levels and conduction band states. In addition, here we include a correlated hybridization term, which depends on the local-level occupation number involved. This term breaks particle-hole symmetry (even when U + 2Ed = 0), enhances charge fluctuations on local levels and as a consequence strongly modifies the crossover between the Hamiltonian fixed-points, even suppressing one or other. We exemplify these behaviors showing data obtained from the Numerical Renormalization Group (NRG) computation for the impurity temperature-dependent specific heat, entropy and magnetic susceptibility. The interleaving procedure is used to recover the continuum spectrum after the NRG-logarithmic discretization of the conduction band. Fundação de Amparo à Pesquisa do Estado de São Paulo - FAPESP.

  15. Nonequilibrium transport in the Anderson-Holstein model with interfacial screening

    NASA Astrophysics Data System (ADS)

    Perfetto, Enrico; Stefanucci, Gianluca

    Image charge effects in nanoscale junctions with strong electron-phonon coupling open the way to unexplored physical scenarios. Here we present a comprehensive study of the transport properties of the Anderson-Holstein model in the presence of dot-lead repulsion. We propose an accurate many-body approach to deal with the simultaneous occurrence of the Franck-Condon blockade and the screening-induced enhancement of the polaron mobility. Remarkably, we find that a novel mechanism of negative differential conductance origins from the competition between the charge blocking due to the electron-phonon interaction and the charge deblocking due to the image charges. An experimental setup to observe this phenomenon is discussed. References [1]E. Perfetto, G. Stefanucci and M. Cini, Phys. Rev. B 85, 165437 (2012). [2] E. Perfetto and G. Stefanucci, Phys. Rev. B 88, 245437 (2013). [3] E. Perfetto and G. Stefanucci, Journal of Computational Electronics 14, 352 (2015). E.P. and G.S. acknowledge funding by MIUR FIRB Grant No. RBFR12SW0J.

  16. The anomalous Floquet-Anderson insulator as a non-adiabatic quantized charge pump

    NASA Astrophysics Data System (ADS)

    Titum, Paraj; Berg, Erez; Rudner, Mark S.; Refael, Gil; Lindner, Netanel H.

    Periodically driven quantum systems provide a novel and versatile platform for realizing topological phenomena. Among these are analogs of topological insulators and superconductors, attainable in static systems; however, some of these phenomena are unique to the periodically driven case. Here, we show that disordered, periodically driven systems admit an ``anomalous'' two dimensional phase, whose quasi-energy spectrum consists of chiral edge modes that coexist with a fully localized bulk - an impossibility for static Hamiltonians. This unique situation serves as the basis for a new topologically-protected non-equilibrium transport phenomenon: quantized non-adiabatic charge pumping. We identify the bulk topological invariant that characterizes the new phase (which we call the ``anomalous Floquet Anderson Insulator'', or AFAI). We provide explicit models which constitute a proof of principle for the existence of the new phase. Finally, we present evidence that the disorder-driven transition from the AFAI to a trivial, fully localized phase is in the same universality class as the quantum Hall plateau transition.

  17. Application of the S=1 underscreened Anderson lattice model to Kondo uranium and neptunium compounds

    NASA Astrophysics Data System (ADS)

    Thomas, Christopher; da Rosa Simões, Acirete S.; Iglesias, J. R.; Lacroix, C.; Perkins, N. B.; Coqblin, B.

    2011-01-01

    Magnetic properties of uranium and neptunium compounds showing the coexistence of the Kondo screening effect and ferromagnetic order are investigated within the Anderson lattice Hamiltonian with a two-fold degenerate f level in each site, corresponding to 5f2 electronic configuration with S=1 spins. A derivation of the Schrieffer-Wolff transformation is presented and the resulting Hamiltonian has an effective f-band term, in addition to the regular exchange Kondo interaction between the S=1 f spins and the s=1/2 spins of the conduction electrons. The resulting effective Kondo lattice model can describe both the Kondo regime and a weak delocalization of the 5f electrons. Within this model we compute the Kondo and Curie temperatures as a function of model parameters, namely the Kondo exchange interaction constant JK, the magnetic intersite exchange interaction JH, and the effective f bandwidth. We deduce, therefore, a phase diagram of the model which yields the coexistence of the Kondo effect and ferromagnetic ordering and also accounts for the pressure dependence of the Curie temperature of uranium compounds such as UTe.

  18. Eigenfunction structure and scaling of two interacting particles in the one-dimensional Anderson model

    NASA Astrophysics Data System (ADS)

    Frahm, Klaus M.

    2016-04-01

    The localization properties of eigenfunctions for two interacting particles in the one-dimensional Anderson model are studied for system sizes up to N = 5000 sites corresponding to a Hilbert space of dimension ≈107 using the Green function Arnoldi method. The eigenfunction structure is illustrated in position, momentum and energy representation, the latter corresponding to an expansion in non-interacting product eigenfunctions. Different types of localization lengths are computed for parameter ranges in system size, disorder and interaction strengths inaccessible until now. We confirm that one-parameter scaling theory can be successfully applied provided that the condition of N being significantly larger than the one-particle localization length L1 is verified. The enhancement effect of the two-particle localization length L2 behaving as L2 ~ L21 is clearly confirmed for a certain quite large interval of optimal interactions strengths. Further new results for the interaction dependence in a very large interval, an energy value outside the band center, and different interaction ranges are obtained.

  19. Finite-size corrections for ground states of Edwards-Anderson spin glasses

    NASA Astrophysics Data System (ADS)

    Boettcher, Stefan; Falkner, Stefan

    2012-05-01

    Extensive computations of ground-state energies of the Edwards-Anderson spin glass on bond-diluted, hypercubic lattices are conducted in dimensions d=3, ..., 7. Results are presented for bond densities exactly at the percolation threshold, p=pc, and deep within the glassy regime, p>pc, where finding ground states is one of the hardest combinatorial optimization problems. Finite-size corrections of the form 1/Nω are shown to be consistent throughout with the prediction ω=1-y/d, where y refers to the "stiffness" exponent that controls the formation of domain wall excitations at low temperatures. At p=pc, an extrapolation for d→∞ appears to match our mean-field results for these corrections. In the glassy phase, however, ω does not approach its anticipated mean-field value of 2/3, obtained from simulations of the Sherrington-Kirkpatrick spin glass on an N-clique graph. Instead, the value of ω reached at the upper critical dimension matches another type of mean-field spin glass models, namely those on sparse random networks of regular degree called Bethe lattices.

  20. Initiating tumor banking for translational research: MD Anderson and Liverpool experience.

    PubMed

    Mishra, A; Pandey, A; Shaw, R

    2007-01-01

    The ultimate progress in the cancer diagnosis and therapy has only been possible with the ongoing translational research that is likely to play a very important role in future as well. Hence the importance of such translation from bedside to bench and vis versa cannot be over-emphasized. Accordingly it has become more important to collect tumor samples along with the clinical information in a systematic manner to perform a good basic science research in future. With a population of over a billion and a heavy burden of cancer, India has the 'biggest' potential to establish the 'largest' tumor bank across the globe. Establishing a tumor bank involves money and manpower that may not be feasible across most of the centers in India. Taking into the considering the model of tumor banking of the two leading institutions of the world (MD Anderson Cancer Center, USA and University Hospital Aintree, Liverpool UK), this article presents the salient tips for a center in India to get started with tumor banking with minimal investment. Furthermore a simplified form of ethical consent is presented for the centers to adapt unanimously. PMID:17401220

  1. Path to poor coherence in the periodic Anderson model from Mott physics and hybridization

    NASA Astrophysics Data System (ADS)

    Amaricci, A.; de'Medici, L.; Sordi, G.; Rozenberg, M. J.; Capone, M.

    2012-06-01

    We investigate the anomalous metal arising from hole-doping the Mott insulating state in the periodic Anderson model. Using dynamical mean-field theory we show that, as opposed to the electron-doped case, in the hole-doped regime the hybridization between localized and delocalized orbitals leads to the formation of composite quasiparticles reminiscent of the Zhang-Rice singlets. We compute the coherence temperature of this state, showing its extremely small value at low doping. As a consequence the weakly doped Mott state deviates from the predictions of Fermi-liquid theory already at small temperatures. The onset of the Zhang-Rice state and of the consequent poor coherence is due to the electronic structure in which both localized and itinerant carriers have to be involved in the formation of the conduction states and to the proximity to the Mott state. By investigating the magnetic properties of this state, we discuss the relation between the anomalous metallic properties and the behavior of the magnetic degrees of freedom.

  2. Health assessment for Anderson Development Company, Adrian, Michigan, Region 5. CERCLIS No. MID002931228. Final report

    SciTech Connect

    Not Available

    1989-03-10

    The Anderson Development Company (ADC) site has been placed on the National Priorities List (NPL). From approximately 1968 to 1979 ADC manufactured 4,4'-methylene-bis(2-chloroaniline) (MBOCA), also known under the trademark names of MOCA and Curene 422. In 1978 the National Institute for Occupational Safety and Health recommended that MBOCA be regulated as a human carcinogen. Discharges of waste waters and air emissions from ADC during the production of MBOCA eventually caused contamination in company lagoons, sludges, and effluents; in municipal sewer influent, effluent, and sludges; in surface-water drains and the Raisin River; and in soil, street sweepings, and residences within a 1-mile radius of the plant. In 1979 and 1980, detectable levels of MBOCA were found in urine specimens collected from ADC and user-plant employees and members of their families. MBOCA may have been carried out of the manufacturing plant on the shoes and clothing of the employees and deposited in their residence. Detectable concentrations of MBOCA were also found in urine specimens of some children living near the site. Because the documented contamination created a continuing potential for environment and human exposure, comprehensive remedial measures were implemented during 1980 and 1981. The site is of potential public health concern because a risk to human health may exist from possible exposure to a hazardous substance at levels that may result in adverse health effects over time; human exposure to MBOCA has occurred/may be still occurring via contaminated soil and garden sources of food.

  3. Kondo insulators modeled by the one-dimensional Anderson lattice: A numerical-renormalization-group study

    SciTech Connect

    Guerrero, M.; Yu, C.C.

    1995-04-15

    In order to better understand Kondo insulators, we have studied both the symmetric and asymmetric Anderson lattices at half filling in one dimension using the density-matrix formulation of the numerical renormalization group. The asymmetric case is treated in the mixed-valence regime. We have calculated the charge gap, the spin gap, and the quasiparticle gap as a function of the repulsive interaction {ital U} using open boundary conditions for lattices as large as 24 sites. We find that the charge gap is larger than the spin gap for all {ital U} for both the symmetric and asymmetric cases. Ruderman-Kittel-Kasuya-Yosida interactions are evident in the {ital f}-spin--{ital f}-spin correlation functions at large {ital U} in the symmetric case, but are suppressed in the asymmetric case as the {ital f} level approaches the Fermi energy. This suppression can also be seen in the staggered susceptibility {chi}({ital q}=2{ital k}{sub {ital F}}) and it is consistent with neutron scattering measurements of {chi}({ital q}) in CeNiSn.

  4. Functional-integral study of the asymmetric Anderson model for dilute fluctuating-valence systems

    NASA Astrophysics Data System (ADS)

    Xianxi, Dai; Ting, Chin-Sen

    1983-11-01

    The functional-integral method in the harmonic approximation which was developed by Amit and Keiter has been extended to study the asymmetric Anderson model. This model gives a valid description of dilute rare-earth ions in metal. The magnetic susceptibility and the occupation number of the localized or f electrons are expressed in terms of some series of double integrals. These double integrals are evaluated numerically by an integration method in number theory. Our results for the temperature-dependent magnetic susceptibility agree quite well with those of renormalization-group calculation by Krishna-Murthy et al. for the f level lying above the Fermi level. However, when the f level lies below the Fermi level, the result of the present approximation loses its agreement with that of the renormalization-group calculation at low temperatures. The f-electron occupation number has also been calculated as a function of temperature and as a function of the energy level of f electrons.

  5. Anderson lattice in the intermediate valence compound Ce3Ni2B2N3-δ

    NASA Astrophysics Data System (ADS)

    Ali, Tahir; Bauer, Ernst; Hilscher, Gerfried; Michor, Herwig

    2011-03-01

    We have studied magnetic, thermodynamic, and transport properties of Ce3Ni2B2N3-δ and its solid solution with the Tc≃13 K superconductor La3Ni2B2N3-δ. The solid solution (La,Ce)3Ni2B2N3-δ reveals a rapid reduction of Tc by increasing the Ce content with a complete suppression of superconductivity at the composition La2.85Ce0.15Ni2B2N3-δ. The low-temperature properties characterize Ce3Ni2B2N3-δ as an intermediate valence system with a moderately enhanced Sommerfeld value γ≃54 mJ/mol K2 and a susceptibility χ0≃1.6×10-3 emu/mol, increased by about one order of magnitude as compared to the respective value χ0≃0.2×10-3 emu/mol of superconducting La3Ni2B2N3-δ (γ=26 mJ/mol K2) which serves as reference with a nonmagnetic rare earth ion. The electrical resistivity and thermoelectric power of Ce3Ni2B2N3-δ are analyzed in terms of the degenerate Anderson lattice model revealing a characteristic Kondo temperature TKALM~1100 K.

  6. Non-equilibrium STLS approach to transport properties of single impurity Anderson model

    NASA Astrophysics Data System (ADS)

    Rezai, Raheleh; Ebrahimi, Farshad

    2014-04-01

    In this work, using the non-equilibrium Keldysh formalism, we study the effects of the electron-electron interaction and the electron-spin correlation on the non-equilibrium Kondo effect and the transport properties of the symmetric single impurity Anderson model (SIAM) at zero temperature by generalizing the self-consistent method of Singwi, Tosi, Land, and Sjolander (STLS) for a single-band tight-binding model with Hubbard type interaction to out of equilibrium steady-states. We at first determine in a self-consistent manner the non-equilibrium spin correlation function, the effective Hubbard interaction, and the double-occupancy at the impurity site. Then, using the non-equilibrium STLS spin polarization function in the non-equilibrium formalism of the iterative perturbation theory (IPT) of Yosida and Yamada, and Horvatic and Zlatic, we compute the spectral density, the current-voltage characteristics and the differential conductance as functions of the applied bias and the strength of on-site Hubbard interaction. We compare our spectral densities at zero bias with the results of numerical renormalization group (NRG) and depict the effects of the electron-electron interaction and electron-spin correlation at the impurity site on the aforementioned properties by comparing our numerical result with the order U2 IPT. Finally, we show that the obtained numerical results on the differential conductance have a quadratic universal scaling behavior and the resulting Kondo temperature shows an exponential behavior.

  7. Basic Properties of Conductivity and Normal Hall Effect in the Periodic Anderson Model

    NASA Astrophysics Data System (ADS)

    Watanabe, Shinji; Miyake, Kazumasa

    2016-04-01

    Exact formulas of diagonal conductivity σxx and Hall conductivity σxy are derived from the Kubo formula in hybridized two-orbital systems with arbitrary band dispersions. On the basis of the theoretical framework for the Fermi liquid based on these formulas, the ground-state properties of the periodic Anderson model with electron correlation and weak impurity scattering are studied on the square lattice. It is shown that imbalance of the mass-renormalization factors causes remarkable increase in σxx and σxy in the valence-fluctuation regime as the f level increases while the cancellation of the renormalization factors causes slight increase in σxx and σxy in the Kondo regime. The Hall coefficient RH shows almost constant behavior in both the regimes. Near half filling, RH is expressed by the total hole density as R{H} = 1/(bar{n}{hole}e) while RH approaches zero near quarter filling, which reflects the curvature of the Fermi surface. These results hold as far as the damping rate for f electrons is less than about 10% of the renormalized hybridization gap. From these results we discuss pressure dependence of residual resistivity and normal Hall effect in Ce- and Yb-based heavy electron systems.

  8. Multifractal structure of eigenstates in the Anderson model with long-range off-diagonal disorder

    NASA Astrophysics Data System (ADS)

    Parshin, D. A.; Schober, H. R.

    1998-05-01

    The spectrum of eigenvalues and the spatial structure of eigenstates for the Anderson model with long-range off-diagonal disorder (Vij=(+/-)/\\|Ri-Rj\\|d) is investigated numerically where Ri are Poisson-distributed random points in d-dimensional space. For this marginal case all states in the system are delocalized. Analyzing the scaling with system size of the inverse participation numbers for the most extended modes we find that these states exhibit a self-similar multifractal structure. The generalized dimensions, Dq, and the multifractal spectrum, f(α), are calculated. For d=3 the information dimension D1=2.65 and the correlation dimension D2=2.33 that characterizes the power-law behavior of the averaged two-particle Green function. The temporal autocorrelation function C(t) built from the eigenstates of the most dispersive oscillator exhibits an nondiffusive algebraic decay C(t)~t-δ with the exponent δ≡D~2=D2/d reflecting the generalized multifractal dimension of the local density of states.

  9. Investigation of Anderson localization in disordered heterostructures irradiated by a Gaussian beam

    NASA Astrophysics Data System (ADS)

    Ardakani, Abbas Ghasempour

    2016-02-01

    The propagation of a Gaussian beam through a one-dimensional disordered media is studied. By employing the transfer matrix method, the localization length as a function of frequency is calculated for different values of transverse coordinate r. It is demonstrated that the localization length significantly depends on r in different frequency ranges. This result is in contrast to those reported for a plane wave incident on disordered structures in which the localization length is transversely constant. For some frequency regions, the peak of localization length is red-shifted and becomes smaller with increasing the transverse coordinate. At some frequencies, the system is in the localized state for particular values of r, while at other r values the system is in the extend regime at the same frequencies. It is observed that the quality of localization at each frequency depends on r. To quantify the localization behavior of the whole Gaussian beam, a modified localization length is defined in terms of the input and output powers of the Gaussian beam where the dependence of Anderson localization on the transverse coordinate is considered. It is suggested that this modified localization length is used in experiments performed for study of wave propagation in one-dimensional random media under illumination of laser beams.

  10. Anderson Localization for Schrödinger Operators on with Strongly Mixing Potentials

    NASA Astrophysics Data System (ADS)

    Bourgain, Jean; Schlag, Wilhelm

    In this paper we show that for a.e. x∈[ 0,2 π) the operators defined on as and with Dirichlet condition ψ- 1= 0, have pure point spectrum in with exponentially decaying eigenfunctions where δ > 0 and are small. As it is a simple consequence of known techniques that for small λ one has [- 2 +δ, 2-δ]⊂ spectrum (H(x)) for a.e.x∈[ 0, 2 π), we thus established Anderson localization on the spectrum up to the edges and the center. More general potentials than cosine can be treated, but only those energies with nonzero spectral density are allowed. Finally, we prove the same result for operators on the whole line with potential , where A:?2-->?2 is a hyperbolic toral automorphism, F∈C1(?2), ∫F= 0, and λ small. The basis for our analysis is an asymptotic formula for the Lyapunov exponent for λ--> 0 by Figotin-Pastur, and generalized by Chulaevski-Spencer. We combine this asymptotic expansion with certain martingale large deviation estimates in order to apply the methods developed by Bourgain and Goldstein in the quasi-periodic case.

  11. Anderson-like alkoxo-polyoxovanadate clusters serving as unprecedented second building units to construct metal-organic polyhedra.

    PubMed

    Zhang, Yu-Teng; Wang, Xin-Long; Li, Shuang-Bao; Gong, Ya-Ru; Song, Bai-Qiao; Shao, Kui-Zhan; Su, Zhong-Min

    2016-08-11

    Unprecedented Anderson-like alkoxo-polyoxovanadate [V6O6(OCH3)9(μ6-SO4)(COO)3](2-) polyanions can serve as 3-connected second building units (SBUs) that assemble with dicarboxylate or tricarboxylate ligands to form a new family of metal organic tetrahedrons of V4E6 and V4F4 type (V = vertex, E = edge, and F = face). To our knowledge, this alkoxo-polyoxovanadate-based SBU is the first ever reported. PMID:27363544

  12. [Heart involvement in Anderson-Fabry disease: Italian recommendations for diagnostic, follow-up and therapeutic management].

    PubMed

    Pieruzzi, Federico; Pieroni, Maurizio; Zachara, Elisabetta; Marziliano, Nicola; Morrone, Amelia; Cecchi, Franco

    2015-11-01

    Anderson-Fabry disease is a rare X-linked lysosomal storage disorder caused by mutations of the GLA gene that encodes alpha-galactosidase A. It is characterized by a multisystemic involvement: the renal, neurological, heart, cochleovestibular and cutaneous systems are the most damaged. Morbidity and mortality of Anderson-Fabry disease depend on renal insufficiency, heart failure and nervous system involvement. Left ventricular hypertrophy is the most common cardiac manifestation followed by conduction system disease, valve dysfunction, and arrhythmias. Mild to moderate left ventricular hypertrophy may simulate a non-obstructive hypertrophic cardiomyopathy. Management of Anderson-Fabry disease starting from the diagnosis of cardiac involvement, the prevention of complications, the therapeutic aspects, up to appropriate clinical follow-up, requires a multidisciplinary approach. According to recent management guidelines, only few evidence-based data are available to guide the clinical and therapeutic approach to this rare disease. An Italian Board, composed by nephrologists, cardiologists, geneticists, pediatricians and neurologists has been established in order to approve by consensus a diagnostic and therapeutic management protocol. The authors report the results of this cardiologic management consensus. PMID:26571477

  13. Petrographic characteristics of the Wyodak-Anderson coal bed (Paleocene), Powder River Basin, Wyoming, U.S.A.

    USGS Publications Warehouse

    Warwick, P.D.; Stanton, R.W.

    1988-01-01

    Six lithofacies of the thick ( > 30 m) Wyodak-Anderson subbituminous coal bed of the Fort Union Formation (Paleocene), Powder River Basin, Wyoming, can be delimited using megascopic and petrographic data. Previous lithofacies analysis of the rock types associated with the Wyodak-Anderson bed suggested that raised peat accumulated in restricted parts of an inland flood plain. The peat bodies were separated by deposits of contemporaneous, possibly anastomosed channels. In this study, megascopic descriptions from four mine highwalls of the Wyodak-Anderson coal bed were found to be similar to facies defined by microscopic data from core and highwall samples. The data indicate that the upper and lower parts of the coal bed are rich in preserved wood remains (for instance, humotelinite), whereas the middle part of the bed contains comparatively larger amounts of material that resulted from degradation and comminution of the peat (e.g. eugelinite). The facies are interpreted to be the result of different chemical and biological environments at the time of peat formation. ?? 1988.

  14. On Planetary Evolution and the Evolution of Planetary Science During the Career of Don Anderson

    NASA Astrophysics Data System (ADS)

    Solomon, S. C.

    2003-12-01

    The planets of our solar system have long been viewed by Don Anderson as laboratories for testing general aspects of planetary evolution and as points of comparison to the Earth. I was fortunate to have been a student 39 years ago in a course at Caltech that Don taught with Bob Kovach on the interiors of the Earth and the planets. At that time, Mariner 4 had not yet flown by Mars, the lunar Ranger program was still in progress, and it was permissible to entertain the hypothesis that all of the terrestrial planets were identical in bulk composition. In the last four decades spacecraft have visited every planet from Mercury to Neptune; samples from the Moon, Mars, asteroids, and comets reside in our laboratories; and more than 100 planets have been discovered orbiting other stars. More importantly, traditionally distinct fields have merged to the point where planetary scientists must be conversant with the findings and modes of thinking from astronomy and biology as well as the geosciences. A few examples illustrate this confluence. Theoretical models for the structure of the atmospheres of gas-giant planets led to the first astronomical detection of an extrasolar planetary atmosphere for the transiting planet HD209458b. Although the atmospheric models were based on those for solar-system gas giants, the 3.5-day orbital period means that this planet is 100 times closer to its star than Jupiter is to the Sun, its effective temperature is 1100 K, and the detected signature of the planetary atmosphere was absorption by neutral sodium. Sodium in Mercury's exosphere, detected astronomically from Earth, figures into the question of how the terrestrial planets came to have distinct bulk compositions. Hypotheses to account for Mercury's high uncompressed density, and by inference its high ratio of metal to silicate, range from chemical gradients in the early solar nebula to preferential removal of silicates from a differentiated protoplanet by nebular heating or giant impact

  15. The University of Texas M.D. Anderson Cancer Center Proton Therapy Facility

    SciTech Connect

    Smith, Alfred; Newhauser, Wayne; Latinkic, Mitchell; Hay, Amy; Cox, James; McMaken, Bruce; Styles, John

    2003-08-26

    The University of Texas M.D. Anderson Cancer Center (MDACC), in partnership with Sanders Morris Harris Inc., a Texas-based investment banking firm, and The Styles Company, a developer and manager of hospitals and healthcare facilities, is building a proton therapy facility near the MDACC main complex at the Texas Medical Center in Houston, Texas USA. The MDACC Proton Therapy Center will be a freestanding, investor-owned radiation oncology center offering state-of-the-art proton beam therapy. The facility will have four treatment rooms: three rooms will have rotating, isocentric gantries and the fourth treatment room will have capabilities for both large and small field (e.g. ocular melanoma) treatments using horizontal beam lines. There will be an additional horizontal beam room dedicated to physics research and development, radiation biology research, and outside users who wish to conduct experiments using proton beams. The first two gantries will each be initially equipped with a passive scattering nozzle while the third gantry will have a magnetically swept pencil beam scanning nozzle. The latter will include enhancements to the treatment control system that will allow for the delivery of proton intensity modulation treatments. The proton accelerator will be a 250 MeV zero-gradient synchrotron with a slow extraction system. The facility is expected to open for patient treatments in the autumn of 2005. It is anticipated that 675 patients will be treated during the first full year of operation, while full capacity, reached in the fifth year of operation, will be approximately 3,400 patients per year. Treatments will be given up to 2-shifts per day and 6 days per week.

  16. Evaluating Quality in Clinical Cancer Research: The M.D. Anderson Cancer Center Experience

    PubMed Central

    Cox, James D.; Giralt, Sergio A.; Veazie, Mary L.; Ajani, Jaffer A.; Bruner, Janet M.; Chan, Ka Wah; Hittelman, Walter N.; Hunt, Kelly K.; Iyer, Revathy B.; Karp, Daniel D.; Kuban, Deborah A.; Lippman, Scott M.; Raad, Issam I.; Rodriguez-Bigas, Miguel A.; Zwelling, Leonard A.; Markman, Maurie

    2009-01-01

    Background Despite the unquestionable importance of clinically oriented research designed to test the safety and efficacy of new therapies in patients with malignant disease, there is limited information regarding strategies to evaluate the quality of such efforts at academic institutions. Methods To address this issue, a committee of senior faculty at the University of Texas M.D. Anderson Cancer Center established specific criteria by which investigators from all departments engaged in clinical research could be formally evaluated. Scoring criteria were established and revised based on the results of a pilot study. Beginning in January 2004, the committee evaluated all faculty involved in clinical research within 35 departments. Scores for individual faculty members were assigned on a scale of 1 (outstanding) to 5; a score of 3 was set as the standard for the institution. Each department also received a score. The results of the evaluation were shared with departmental chairs and the Chief Academic Officer. Results 392 faculty were evaluated. The median score was 3. Full professors more frequently received a score of 1, but all faculty ranks received scores of 4 and 5. As a group, tenure/tenure track faculty achieved superior scores compared to nontenure track faculty. Conclusions Based on our experience, we believe it is possible to conduct a rigorous consensus-based evaluation of the quality of clinical cancer research being conducted at an academic medical center. It is reasonable to suggest such evaluations can be used as a management tool and may lead to higher-quality clinical research. PMID:19571599

  17. Incidence of Atypical Femur Fractures in Cancer Patients: The MD Anderson Cancer Center Experience.

    PubMed

    Edwards, Beatrice J; Sun, Ming; West, Dennis P; Guindani, Michele; Lin, Yan Heather; Lu, Huifang; Hu, Mimi; Barcenas, Carlos; Bird, Justin; Feng, Chun; Saraykar, Smita; Tripathy, Debasish; Hortobagyi, Gabriel N; Gagel, Robert; Murphy, William A

    2016-08-01

    Atypical femoral fractures (AFFs) are rare adverse events attributed to bisphosphonate (BP) use. Few cases of AFF in cancer have been described; the aim of this study is to identify the incidence and risk factors for AFF in a large cancer center. This retrospective study was conducted at the MD Anderson Cancer Center. The incidence rate of AFF among BP users was calculated from January 1, 2004 through December 31, 2013. The control group (n = 51) included 2 or 3 patients on BPs matched for age (≤1 year) and gender. Logistic regression analysis was used to assess the relationship between clinical characteristics and AFF. Twenty-three AFF cases were identified radiographically among 10,587 BP users, the total BP exposure was 53,789 months (4482 years), and the incidence of AFF in BP users was 0.05 cases per 100,000 person-years. Meanwhile, among 300,553 patients who did not receive BPs there were 2 cases of AFF as compared with the 23 cases noted above. The odds ratio (OR) of having AFF in BP users was 355.58 times higher (95% CI, 84.1 to 1501.4, p < 0.0001) than the risk in non-BP users. The OR of having AFF in alendronate users was 5.54 times greater (OR 5.54 [95% CI, 1.60 to 19.112, p = 0.007]) than the odds of having AFF among other BP users. Patients who were on zoledronic acid (ZOL) had smaller odds of developing AFF compared with other BP users in this matched case control sample. AFFs are rare, serious adverse events that occur in patients with cancer who receive BP therapy. Patients with cancer who receive BPs for prior osteoporosis therapy or for metastatic cancer are at higher risk of AFF. © 2016 American Society for Bone and Mineral Research. PMID:26896384

  18. The University of Texas M.D. Anderson Cancer Center Proton Therapy Facility

    NASA Astrophysics Data System (ADS)

    Smith, Alfred; Newhauser, Wayne; Latinkic, Mitchell; Hay, Amy; McMaken, Bruce; Styles, John; Cox, James

    2003-08-01

    The University of Texas M.D. Anderson Cancer Center (MDACC), in partnership with Sanders Morris Harris Inc., a Texas-based investment banking firm, and The Styles Company, a developer and manager of hospitals and healthcare facilities, is building a proton therapy facility near the MDACC main complex at the Texas Medical Center in Houston, Texas USA. The MDACC Proton Therapy Center will be a freestanding, investor-owned radiation oncology center offering state-of-the-art proton beam therapy. The facility will have four treatment rooms: three rooms will have rotating, isocentric gantries and the fourth treatment room will have capabilities for both large and small field (e.g. ocular melanoma) treatments using horizontal beam lines. There will be an additional horizontal beam room dedicated to physics research and development, radiation biology research, and outside users who wish to conduct experiments using proton beams. The first two gantries will each be initially equipped with a passive scattering nozzle while the third gantry will have a magnetically swept pencil beam scanning nozzle. The latter will include enhancements to the treatment control system that will allow for the delivery of proton intensity modulation treatments. The proton accelerator will be a 250 MeV zero-gradient synchrotron with a slow extraction system. The facility is expected to open for patient treatments in the autumn of 2005. It is anticipated that 675 patients will be treated during the first full year of operation, while full capacity, reached in the fifth year of operation, will be approximately 3,400 patients per year. Treatments will be given up to 2-shifts per day and 6 days per week.

  19. Cancer-related symptom assessment in France: validation of the French M. D. Anderson Symptom Inventory.

    PubMed

    Guirimand, Frédéric; Buyck, Jean-François; Lauwers-Allot, Elisabeth; Revnik, Julia; Kerguen, Thierry; Aegerter, Philippe; Brasseur, Louis; Cleeland, Charles S

    2010-04-01

    This multicenter study was intended to validate the French version of the M. D. Anderson Symptom Inventory (MDASI-Fr) in French cancer patients (n=162) with solid tumors or hematological malignancies. The European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-C30) was used as a part of the validation. Factor analysis showed three underlying constructs for symptom items: general symptoms (pain, fatigue, disturbed sleep, shortness of breath, drowsiness, dry mouth, and numbness or tingling items); emotional and cognitive components (distress, sadness, and remembering items); and a gastrointestinal component (nausea, vomiting, and lack of appetite items), with Cronbach's alphas of 0.79, 0.73, and 0.71, respectively. Convergent validity was established by comparing MDASI-Fr items with the EORTC QLQ-C30 scale and the Brief Pain Inventory (BPI). Overall, the 19-item MDASI-Fr score correlated well with the QLQ-C30 global health status, and the pain item of the MDASI-Fr was highly correlated with the short form of the BPI. The most prevalent symptoms were fatigue, distress, dry mouth, and pain. Twenty-five percent of patients reported moderate or severe pain (numeric rating scale >4 on 0-10 severity ratings). Physician ratings of global change on a second visit were significantly associated with changes in patient ratings on the MDASI-Fr, supporting the sensitivity of the measure. Symptoms interfered most with work and general activity. The MDASI-Fr is a valid and reliable tool for measuring symptom severity and interference in French cancer patients. PMID:20413059

  20. Cycle Analysis

    Energy Science and Technology Software Center (ESTSC)

    2012-03-20

    1. The Cycle Analysis code is an Microsoft Excel code that performs many different types of thermodynamic cycle analysis for power producing systems. The code will calculate the temperature and pressure and all other thermodynamic properties at the inlet and outlet of each component. The code also calculates the power that is produced, the efficiency, and the heat transported in the heater, gas chiller and recuperators. The code provides a schematic of the loop andmore » provides the temperature and pressure at each location in the loop. The code also provides a T-S (temperature-entropy) diagram of the loop and often it provides an pressure enthalpy plot as well. 2. This version of the code concentrates on supercritical CO2 power cycles, but by simply changing the name of the working fluid many other types of fluids can be analyzed. The Cycle Analysis code provided here contains 18 different types of power cycles. Each cycle is contained in one worksheet or tab that the user can select. The user can change the yellow highlighted regions to perform different thermodynamic cycle analysis.« less

  1. Cycling injuries.

    PubMed Central

    Cohen, G. C.

    1993-01-01

    Bicycle-related injuries have increased as cycling has become more popular. Most injuries to recreational riders are associated with overuse or improper fit of the bicycle. Injuries to racers often result from high speeds, which predispose riders to muscle strains, collisions, and falls. Cyclists contact bicycles at the pedals, seat, and handlebars. Each is associated with particular cycling injuries. Images Figure 1 Figure 3 Figure 4 Figure 5 PMID:8471908

  2. The magnetocaloric effect with critical behavior of a periodic Anderson-like organic polymer.

    PubMed

    Ding, L J; Zhong, Y; Fan, S W; Zhu, L Y

    2016-01-01

    We study the magnetocaloric effect and the critical behavior of a periodic Anderson-like organic polymer using Green's function theory, in which the localized f orbitals hybridize with the conduction orbitals at even sites. The field-induced metal-insulator transitions with the magnetic Grüneisen parameter showing |Γh|∼T(-1) power-law critical behaviour are revealed, which provides a new thermodynamic means for probing quantum phase transitions. It is found that the competition of up-spin and down-spin hole excitations is responsible for the double peak structure of magnetic entropy change (-ΔS) for the dominant Kondo coupling case, implying a double magnetic cooling process via demagnetization, which follows a power law dependence of the magnetic field h: -ΔS∼h(n). The local exponent n tends to 1 and 2 below and above TC, while has a minimum of 0.648 at TC, which is in accordance with the experimental observation of perovskite manganites Pr0.55Sr0.45MnO3 and Nd0.55Sr0.45MnO3 (J. Y. Fan et al., Appl. Phys. Lett., 2011, 98, 072508; Europhys. Lett., 2015, 112, 17005) corresponding to the conventional ferromagnets within the mean field theory -ΔS∼h(2/3). At TC, the -ΔS∼h curves with a convex curvature superpose each other for small V values, which are separated by the large V case, distinguishing the RKKY interaction and Kondo coupling explicitly. Furthermore, the critical scaling law n(TC) = 1 + (β- 1)/(β + γ) = 1 + 1/δ(1 - 1/β) is related to the critical exponents (β, γ, and δ) extracted from the Arrott-Noakes equation of state and the Kouvel-Fisher method, which fulfill the Widom scaling relation δ = 1 + γβ(-1), indicating the self-consistency and reliability of the obtained results. In addition, based on the scaling hypothesis through checking the scaling analysis of magnetization, the M-T-h curves collapse into two independent universal branches below and above TC. PMID:26617276

  3. Non-equilibrium STLS approach to transport properties of single impurity Anderson model

    SciTech Connect

    Rezai, Raheleh Ebrahimi, Farshad

    2014-04-15

    In this work, using the non-equilibrium Keldysh formalism, we study the effects of the electron–electron interaction and the electron-spin correlation on the non-equilibrium Kondo effect and the transport properties of the symmetric single impurity Anderson model (SIAM) at zero temperature by generalizing the self-consistent method of Singwi, Tosi, Land, and Sjolander (STLS) for a single-band tight-binding model with Hubbard type interaction to out of equilibrium steady-states. We at first determine in a self-consistent manner the non-equilibrium spin correlation function, the effective Hubbard interaction, and the double-occupancy at the impurity site. Then, using the non-equilibrium STLS spin polarization function in the non-equilibrium formalism of the iterative perturbation theory (IPT) of Yosida and Yamada, and Horvatic and Zlatic, we compute the spectral density, the current–voltage characteristics and the differential conductance as functions of the applied bias and the strength of on-site Hubbard interaction. We compare our spectral densities at zero bias with the results of numerical renormalization group (NRG) and depict the effects of the electron–electron interaction and electron-spin correlation at the impurity site on the aforementioned properties by comparing our numerical result with the order U{sup 2} IPT. Finally, we show that the obtained numerical results on the differential conductance have a quadratic universal scaling behavior and the resulting Kondo temperature shows an exponential behavior. -- Highlights: •We introduce for the first time the non-equilibrium method of STLS for Hubbard type models. •We determine the transport properties of SIAM using the non-equilibrium STLS method. •We compare our results with order-U2 IPT and NRG. •We show that non-equilibrium STLS, contrary to the GW and self-consistent RPA, produces the two Hubbard peaks in DOS. •We show that the method keeps the universal scaling behavior and correct

  4. Nutrient cycling.

    PubMed

    Bormann, F H; Likens, G E

    1967-01-27

    The small-watershed approach to problems of nutrient cycling has these advantages. (i) The small watershed is a natural unit of suitable size for intensive study of nutrient cycling at the ecosystem level. (ii) It provides a means of reducing to a minimum, or virtually eliminating, the effect of the difficult-to-measure variables of geologic input and nutrient losses in deep seepage. Control of these variables makes possible accurate measurement of nutrient input and output (erosion) and therefore establishes the relationship of the smaller ecosystem to the larger biospheric cycles. (iii) The small-watershed approach provides a method whereby such important parameters as nutrient release from minerals (weathering) and annual nutrient budgets may be calculated. (iv) It provides a means of studying the interrelationships between the biota and the hydrologic cycle, various nutrient cycles, and energy flow in a single system. (v) Finally, with the small-watershed system we can test the effect of various land-management practices or environmental pollutants on nutrient cycling in natural systems. PMID:17737551

  5. Sample-to-sample fluctuations of the overlap distributions in the three-dimensional Edwards-Anderson spin glass

    NASA Astrophysics Data System (ADS)

    Baños, R. A.; Cruz, A.; Fernandez, L. A.; Gil-Narvion, J. M.; Gordillo-Guerrero, A.; Guidetti, M.; Iñiguez, D.; Maiorano, A.; Mantovani, F.; Marinari, E.; Martin-Mayor, V.; Monforte-Garcia, J.; Muñoz Sudupe, A.; Navarro, D.; Parisi, G.; Perez-Gaviro, S.; Ricci-Tersenghi, F.; Ruiz-Lorenzo, J. J.; Schifano, S. F.; Seoane, B.; Tarancón, A.; Tripiccione, R.; Yllanes, D.

    2011-11-01

    We study the sample-to-sample fluctuations of the overlap probability densities from large-scale equilibrium simulations of the three-dimensional Edwards-Anderson spin glass below the critical temperature. Ultrametricity, stochastic stability, and overlap equivalence impose constraints on the moments of the overlap probability densities that can be tested against numerical data. We found small deviations from the Ghirlanda-Guerra predictions, which get smaller as system size increases. We also focus on the shape of the overlap distribution, comparing the numerical data to a mean-field-like prediction in which finite-size effects are taken into account by substituting delta functions with broad peaks.

  6. Bi-stability in single impurity Anderson model with strong electron-phonon interaction(polaron regime)

    NASA Astrophysics Data System (ADS)

    Eskandari-asl, Amir

    2016-09-01

    We consider a single impurity Anderson model (SIAM) in which the quantum dot(QD) is strongly coupled to a phonon bath in polaron regime. This coupling results in an effective e-e attraction. By computing the self energies using a current conserving approximation which is up to second order in this effective attraction, we show that if the interaction is strong enough, in non particle-hole (PH) symmetric case, the system would be bi-stable and we have hysteresis loop in the I-V characteristic. Moreover, the system shows negative differential conductance in some bias voltage intervals.

  7. Ferromagnetic ordering in Mn-doped quantum wells GaAs-AlGaAs resulting from the virtual Anderson transition

    SciTech Connect

    Agrinskaya, N. V.; Berezovets, V. A.; Bouravlev, A.; Kozub, V. I.

    2014-08-20

    We present our results obtained for Mn-doped GaAs quantum wells where the evidences of the ferromagnetic transition at relatively high temperatures were found at unusually small Mn concentrations. The observed values of hopping resistance at small temperatures evidenced that the samples are deep in the insulating regime. Thus the corresponding estimates of the overlapping integrals can hardly explain the large values of Curie temperatures T{sub c} ≃ 100 K. We develop a theoretical model qualitatively explaining the experimental results basing on the concept of virtual Anderson transition.

  8. Competition between antiferromagnetic order and spin-liquid behavior in the two-dimensional periodic Anderson model at half filling

    SciTech Connect

    Vekic, M.; Cannon, J.W.; Scalapino, D.J.; Scalettar, R.T.; Sugar, R.L. Physics Department, Centenary College, 2911 Centenary Boulevard, Shreveport, Louisiana 71104 Department of Physics, University of California, Santa Barbara, California 93106 )

    1995-03-20

    We study the two-dimensional periodic Anderson model at half filling using quantum Monte Carlo (QMC) techniques. The ground state undergoes a magnetic order-disorder transition as a function of the effective exchange coupling between the conduction and localized bands. Low-lying spin and charge excitations are determined using the maximum entropy method to analytically continue the QMC data. At finite temperature we find a competition between the Kondo effect and antiferromagnetic order which develops in the localized band through Ruderman-Kittel-Kasuya-Yosida interactions.

  9. Joint min-max distribution and Edwards-Anderson's order parameter of the circular 1/f-noise model

    NASA Astrophysics Data System (ADS)

    Cao, Xiangyu; Le Doussal, Pierre

    2016-05-01

    We calculate the joint min-max distribution and the Edwards-Anderson's order parameter for the circular model of 1/f-noise. Both quantities, as well as generalisations, are obtained exactly by combining the freezing-duality conjecture and Jack-polynomial techniques. Numerical checks come with significantly improved control of finite-size effects in the glassy phase, and the results convincingly validate the freezing-duality conjecture. Application to diffusive dynamics is discussed. We also provide a formula for the pre-factor ratio of the joint/marginal Carpentier-Le Doussal tail for minimum/maximum which applies to any logarithmic random energy model.

  10. Persistence of energy-dependent localization in the Anderson-Hubbard model with increasing system size and doping

    NASA Astrophysics Data System (ADS)

    Daley, P.; Wortis, R.

    2016-05-01

    Non-interacting systems with bounded disorder have been shown to exhibit sharp density of state peaks at the band edge which coincide with an energy range of abruptly suppressed localization. Recent work has shown that these features also occur in the presence of on-site interactions in ensembles of two-site Anderson-Hubbard systems at half filling. Here we demonstrate that this effect in interacting systems persists away from half filling, and moreover that energy regions with suppressed localization continue to appear in ensembles of larger systems despite a loss of sharp features in the density of states.

  11. ASCOT data from the 1980 field-measurement program in the Anderson Creek Valley, California. Vol. I

    SciTech Connect

    Gudiksen, P.H.

    1983-04-01

    This report provides a listing of the data acquired during a series of nocturnal drainage flow experiments that were conducted by ASCOT participants in the Anderson Creek valley during September 1980. These experiments were designed to evaluate the transport and dispersion characteristics associated with nocturnal drainage flows. The report includes data from meteorological measurements systems and tracer experiments. The meteorological data include measurements from tethersondes, acoustic sounders, meteorological towers, pilot balloons, optical anemometers, and rawinsondes; while the tracer experiments provided data on the spatial and temporal distributions of perfluorocarbon, heavy methane, sulfur hexafluoride oil fog, tetroons, and radon tracers.

  12. Vapor Compression Cycle Design Program (CYCLE_D)

    National Institute of Standards and Technology Data Gateway

    SRD 49 NIST Vapor Compression Cycle Design Program (CYCLE_D) (PC database for purchase)   The CYCLE_D database package simulates the vapor compression refrigeration cycles. It is fully compatible with REFPROP 9.0 and covers the 62 single-compound refrigerants . Fluids can be used in mixtures comprising up to five components.

  13. Verification of Anderson superexchange in MnO via magnetic pair distribution function analysis and ab initio theory

    DOE PAGESBeta

    Benjamin A. Frandsen; Brunelli, Michela; Page, Katharine; Uemura, Yasutomo J.; Staunton, Julie B.; Billinge, Simon J. L.

    2016-05-11

    Here, we present a temperature-dependent atomic and magnetic pair distribution function (PDF) analysis of neutron total scattering measurements of antiferromagnetic MnO, an archetypal strongly correlated transition-metal oxide. The known antiferromagnetic ground-state structure fits the low-temperature data closely with refined parameters that agree with conventional techniques, confirming the reliability of the newly developed magnetic PDF method. The measurements performed in the paramagnetic phase reveal significant short-range magnetic correlations on a ~1 nm length scale that differ substantially from the low-temperature long-range spin arrangement. Ab initio calculations using a self-interaction-corrected local spin density approximation of density functional theory predict magnetic interactions dominatedmore » by Anderson superexchange and reproduce the measured short-range magnetic correlations to a high degree of accuracy. Further calculations simulating an additional contribution from a direct exchange interaction show much worse agreement with the data. Furthermore, the Anderson superexchange model for MnO is thus verified by experimentation and confirmed by ab initio theory.« less

  14. Verification of Anderson Superexchange in MnO via Magnetic Pair Distribution Function Analysis and ab initio Theory

    NASA Astrophysics Data System (ADS)

    Frandsen, Benjamin A.; Brunelli, Michela; Page, Katharine; Uemura, Yasutomo J.; Staunton, Julie B.; Billinge, Simon J. L.

    2016-05-01

    We present a temperature-dependent atomic and magnetic pair distribution function (PDF) analysis of neutron total scattering measurements of antiferromagnetic MnO, an archetypal strongly correlated transition-metal oxide. The known antiferromagnetic ground-state structure fits the low-temperature data closely with refined parameters that agree with conventional techniques, confirming the reliability of the newly developed magnetic PDF method. The measurements performed in the paramagnetic phase reveal significant short-range magnetic correlations on a ˜1 nm length scale that differ substantially from the low-temperature long-range spin arrangement. Ab initio calculations using a self-interaction-corrected local spin density approximation of density functional theory predict magnetic interactions dominated by Anderson superexchange and reproduce the measured short-range magnetic correlations to a high degree of accuracy. Further calculations simulating an additional contribution from a direct exchange interaction show much worse agreement with the data. The Anderson superexchange model for MnO is thus verified by experimentation and confirmed by ab initio theory.

  15. Verification of Anderson Superexchange in MnO via Magnetic Pair Distribution Function Analysis and ab initio Theory.

    PubMed

    Frandsen, Benjamin A; Brunelli, Michela; Page, Katharine; Uemura, Yasutomo J; Staunton, Julie B; Billinge, Simon J L

    2016-05-13

    We present a temperature-dependent atomic and magnetic pair distribution function (PDF) analysis of neutron total scattering measurements of antiferromagnetic MnO, an archetypal strongly correlated transition-metal oxide. The known antiferromagnetic ground-state structure fits the low-temperature data closely with refined parameters that agree with conventional techniques, confirming the reliability of the newly developed magnetic PDF method. The measurements performed in the paramagnetic phase reveal significant short-range magnetic correlations on a ∼1  nm length scale that differ substantially from the low-temperature long-range spin arrangement. Ab initio calculations using a self-interaction-corrected local spin density approximation of density functional theory predict magnetic interactions dominated by Anderson superexchange and reproduce the measured short-range magnetic correlations to a high degree of accuracy. Further calculations simulating an additional contribution from a direct exchange interaction show much worse agreement with the data. The Anderson superexchange model for MnO is thus verified by experimentation and confirmed by ab initio theory. PMID:27232042

  16. Quantum transparency of Anderson insulator junctions: Statistics of transmission eigenvalues, shot noise, and proximity conductance

    NASA Astrophysics Data System (ADS)

    Nikolić, Branislav K.; Dragomirova, Ralitsa L.

    2005-01-01

    We investigate quantum transport through strongly disordered barriers, made of a material with exceptionally high resistivity that behaves as an Anderson insulator or a “bad metal” in the bulk, by analyzing the distribution of Landauer transmission eigenvalues for a junction where such barrier is attached to two clean metallic leads. We find that scaling of the transmission eigenvalue distribution with the junction thickness (starting from the single interface limit) always predicts a nonzero probability to find high transmission channels even in relatively thick barriers. Using this distribution, we compute the zero frequency shot noise power (as well as its sample-to-sample fluctuations) and demonstrate how it provides a single number characterization of nontrivial transmission properties of different types of disordered barriers. The appearance of open conducting channels, whose transmission eigenvalue is close to one, and corresponding violent mesoscopic fluctuations of transport quantities explain at least some of the peculiar zero-bias anomalies in the Anderson-insulator/superconductor junctions observed in recent experiments [A. Vaknin, A. Frydman, and Z. Ovadyahu, Phys. Rev. B 61, 13037 (2000)]. Our findings are also relevant for the understanding of the role of defects that can undermine quality of thin tunnel barriers made of conventional band insulators.

  17. Development of the M. D. Anderson Cancer Center Gynecologic Applicators for the Treatment of Cervical Cancer: Historical Analysis

    SciTech Connect

    Yordy, John S.; Almond, Peter R.; Delclos, Luis

    2012-03-15

    Purpose: To provide historical background on the development and initial studies of the gynecological (gyn) applicators developed by Dr. Gilbert H. Fletcher, a radiation oncologist and chairperson from 1948 to 1981 of the department at the M.D. Anderson Hospital (MDAH) for Cancer Research in Houston, TX, and to acknowledge the previously unrecognized contribution that Dr. Leonard G. Grimmett, a radiation physicist and chairperson from 1949 to 1951 of the physics department at MDAH, made to the development of the gynecological applicators. Methods and Materials: We reviewed archival materials from the Historical Resource Center and from the Department of Radiation Physics at University of Texas M. D. Anderson Cancer Center, as well as contemporary published papers, to trace the history of the applicators. Conclusions: Dr. Fletcher's work was influenced by the work on gynecologic applicators in the 1940s in Europe, especially work done at the Royal Cancer Hospital in London. Those efforts influenced not only Dr. Fletcher's approach to the design of the applicators but also the methods used to perform in vivo measurements and determine the dose distribution. Much of the initial development of the dosimetry techniques and measurements at MDAH were carried out by Dr. Grimmett.

  18. Surgical Results of Anderson-Hynes Dismembered Pyeloplasty Without Internal Drainage in Adults With Ureteroplevic Junction Obstruction

    PubMed Central

    Yarmohamadi, Aliasghar; Saeedi, Parisa; Hoghabrosadat, Amir

    2015-01-01

    Background: Anderson-Hynes dismembered pyeloplasty is the gold standard therapeutic approach to ureteropelvic junction obstruction (UPJO). Use of a drainage method to protect the suture line from leakage is a matter of controversy. Objectives: We have compared the surgical outcome of Anderson-Hynes dismembered pyeloplasty for UPJO repair, with or without internal stenting. Patients and Methods: Eighty-two patients with UPJO were evaluated from 1996 to 2002. Complicated or emergent cases were excluded. Classic standard dismembered pyeloplasty was performed. Internal drainage, with a double j catheter, was performed in several patients, randomly. Another drain was also placed in the retroperitoneal space. The follow-up of patients was planned weekly, with patient visits and urine analysis and intravenous pyelography (IVP) and diethylene-triamine-pentaacetate (DTPA) scan after one month. Results: The study group consisted of 51 male and 31 female patients, who were mostly in the age range of 20 - 40 years. Comparing the two techniques of pyeloplasty with or without internal drainage, there was no significant difference between groups regarding extravasation and anastomosis complications, such as leakage, stenosis, urinoma formation or evidence of obstruction on postoperative IVP or DTPA scan. However, a higher incidence of catheter related urinary symptoms and flank pain was reported among those with internal stent. Conclusions: Pyeloplasty, with adequate spatulation, hemostasis and a watertight anastomosis, represents the mainstay of successful pyeloplasty and there may be no significant benefit for urethral stenting, especially in non-complicated cases. PMID:26034744

  19. Nailing the coffin shut on doubts that violent video games stimulate aggression: comment on Anderson et al. (2010).

    PubMed

    Huesmann, L Rowell

    2010-03-01

    Over the past half century the mass media, including video games, have become important socializers of children. Observational learning theory has evolved into social-cognitive information processing models that explain that what a child observes in any venue has both short-term and long-term influences on the child's behaviors and cognitions. C. A. Anderson et al.'s (2010) extensive meta-analysis of the effects of violent video games confirms what these theories predict and what prior research about other violent mass media has found: that violent video games stimulate aggression in the players in the short run and increase the risk for aggressive behaviors by the players later in life. The effects occur for males and females and for children growing up in Eastern or Western cultures. The effects are strongest for the best studies. Contrary to some critics' assertions, the meta-analysis of C. A. Anderson et al. is methodologically sound and comprehensive. Yet the results of meta-analyses are unlikely to change the critics' views or the public's perception that the issue is undecided because some studies have yielded null effects, because many people are concerned that the implications of the research threaten freedom of expression, and because many people have their identities or self-interests closely tied to violent video games. PMID:20192555

  20. Anderson acceleration of the Jacobi iterative method: An efficient alternative to Krylov methods for large, sparse linear systems

    NASA Astrophysics Data System (ADS)

    Pratapa, Phanisri P.; Suryanarayana, Phanish; Pask, John E.

    2016-02-01

    We employ Anderson extrapolation to accelerate the classical Jacobi iterative method for large, sparse linear systems. Specifically, we utilize extrapolation at periodic intervals within the Jacobi iteration to develop the Alternating Anderson-Jacobi (AAJ) method. We verify the accuracy and efficacy of AAJ in a range of test cases, including nonsymmetric systems of equations. We demonstrate that AAJ possesses a favorable scaling with system size that is accompanied by a small prefactor, even in the absence of a preconditioner. In particular, we show that AAJ is able to accelerate the classical Jacobi iteration by over four orders of magnitude, with speed-ups that increase as the system gets larger. Moreover, we find that AAJ significantly outperforms the Generalized Minimal Residual (GMRES) method in the range of problems considered here, with the relative performance again improving with size of the system. Overall, the proposed method represents a simple yet efficient technique that is particularly attractive for large-scale parallel solutions of linear systems of equations.

  1. Preliminary report on coal resources of the Wyodak-Anderson coal zone, Powder River Basin, Wyoming and Montana

    USGS Publications Warehouse

    Ellis, Margaret S.; Gunther, Gregory L.; Flores, Romeo M.; Ochs, Allen M.; Stricker, Gary D.; Roberts, Steven B.; Taber, Thomas T.; Bader, Lisa R.; Schuenemeyer, John H.

    1998-01-01

    The National Coal Resource Assessment (NCRA) project by the U.S. Geological Survey is designed to assess US coal with the greatest potential for development in the next 20 to 30 years. Coal in the Wyodak-Anderson (WA) coal zone in the Powder River Basin of Wyoming and Montana is plentiful, clean, and compliant with EPA emissions standards. This coal is considered to be very desirable for development for use in electric power generation. The purpose of this NCRA study was to compile all available data relating to the Wyodak- Anderson coal, correlate the beds that make up the WA coal zone, create digital files pertaining to the study area and the WA coal, and produce a variety of reports on various aspects of the assessed coal unit. This report contains preliminary calculations of coal resources for the WA coal zone and is one of many products of the NCRA study. Coal resource calculations in this report were produced using both public and confidential data from many sources. The data was manipulated using a variety of commercially available software programs and several custom programs. A general description of the steps involved in producing the resource calculations is described in this report.

  2. Menu Cycles.

    ERIC Educational Resources Information Center

    Clayton, Alfred; Almony, John

    The curriculum guide for commercial foods instruction is designed to aid the teacher in communicating the importance of menu cycles in commercial food production. It also provides information about the necessary steps in getting food from the raw form to the finished product, and then to the consumer. In addition to providing information on how to…

  3. Price-Anderson Act Amendments Act of 1986. A report submitted to the Senate, Ninety-Ninth Congress, Second Session, May 21, 1986

    SciTech Connect

    Not Available

    1986-01-01

    The report on proposed legislation (S. 1225) to amend the Price-Anderson Act provisions of the Atomic Energy Act to extend and improve the procedures for compensating the public in the event of a nuclear accident is favorable, but suggest some changes. The bill reauthorizes the Price-Anderson indemnification system for 25 years, increases funds available for victim compensation, and expedites congressional procedures for responding with additional action as needed in the event of the theft or an accident involving nuclear materials. The report outlines the background and need for the legislation, gives a section-by-section analysis, and presents additional views and statements of committee members.

  4. Level repulsion exponent β for many-body localization transitions and for Anderson localization transitions via Dyson Brownian motion

    NASA Astrophysics Data System (ADS)

    Monthus, Cécile

    2016-03-01

    The generalization of the Dyson Brownian motion approach of random matrices to Anderson localization (AL) models (Chalker et al 1996 Phys. Rev. Lett. 77 554) and to many-body localization (MBL) Hamiltonians (Serbyn and Moore 2015 arXiv:1508.07293) is revisited to extract the level repulsion exponent β, where β =1 in the delocalized phase governed by the Wigner-Dyson statistics, β =0 , in the localized phase governed by the Poisson statistics, and 0<{βc}<1 at the critical point. The idea is that the Gaussian disorder variables h i are promoted to Gaussian stationary processes h i (t) in order to sample the disorder stationary distribution with some time correlation τ. The statistics of energy levels can then be studied via Langevin and Fokker-Planck equations. For the MBL quantum spin Hamiltonian with random fields h i , we obtain β =2qn,n+1\\text{EA}(N)/qn,n\\text{EA}(N) in terms of the Edwards-Anderson matrix qnm\\text{EA}(N)\\equiv \\frac{1}{N}{\\sum}i=1N|< {φn}|σ iz|{φm}> {{|}2} for the same eigenstate m  =  n and for consecutive eigenstates m  =  n  +  1. For the Anderson localization tight-binding Hamiltonian with random on-site energies h i , we find β =2{{Y}n,n+1}(N)/≤ft({{Y}n,n}(N)-{{Y}n,n+1}(N)\\right) in terms of the density correlation matrix {{Y}nm}(N)\\equiv {\\sum}i=1N|< {φn}|i> {{|}2}|< i|{φm}> {{|}2} for consecutive eigenstates m  =  n  +  1, while the diagonal element m  =  n corresponds to the inverse participation ratio {{Y}nn}(N)\\equiv {\\sum}i=1N|< {φn}|i> {{|}4} of the eigenstate |{φn}> .

  5. Anderson-Fabry disease: a histopathological study of three cases with observations on the mechanism of production of pain

    PubMed Central

    Kahn, Pauline

    1973-01-01

    A clinical review and histopathological study of three cases of Anderson-Fabry disease is presented and pathological changes in the central and peripheral nervous systems are reported, in some sites for the first time. These are telangiectatic changes in vessels of the sympathetic ganglia in the vertebral trunk; storage of glycolipid in pigmented cells of the substantia nigra and in anterior horn cells; and degeneration of nerve fibres in the dorsal root entry zone and substantia gelatinosa of the spinal cord. The histopathological findings suggest that in this disease pain is due to involvement of dorsal root ganglion cells with associated axonal degeneration of the small fibres in pathways subserving pain. Images PMID:4204059

  6. Price-Anderson Amendments Act of 1986. House of Representatives, Ninety-Ninth Congress, Second Session. August 5, 1986

    SciTech Connect

    Not Available

    1986-01-01

    The committee recommends several amendments to H.R. 3653, a bill designed to improve nuclear insurance procedures. Among the amendments are the inclusion of storage, handling, transportation, treatment, or disposal of, or research and development on and changes dealing with reimbursement procedures and limits. The bill reauthorizes the Price-Anderson Act, but limits liability and creates industry-wide liability in the event of a major accident. The report covers background information and hearings, summarizes the 15 amendments and each section how the bill will effect relevant changes in the Atomic Energy Act of 1954. Dissenting views argue against setting a liability cap on nuclear waste accidents because it discourages safety consciousness on the part of contractors and because there is no precedent in liability insurance for limiting liability.

  7. Heavy-fermion semiconductor behavior of the SU({ital N}{sub {ital d}}) Anderson lattice model

    SciTech Connect

    Hu, L.; Yang, F.; Sun, J. |; Lin, T. |

    1995-08-15

    The heavy-fermion semiconductor behavior of the SU({ital N}{sub {ital d}}) Anderson lattice model is examined by using the slave-boson technique within the framework of mean-field theory. The results show that the slave-boson mean-field theory of this model can present a heavy Fermi liquid or a heavy-fermion semiconductor ground state for different {ital n} values ({ital n} is the total number of the conduction and the on-site {ital f} electrons per lattice site), thus providing a unified description of the heavy Fermi liquid and the heavy-fermion semiconductor. The basic features of this theory are in qualitative agreement with the experimentally observed heavy-fermion semiconductor behavior of some rare-earth compounds.

  8. Variable induction of vitellogenin genes in the varroa mite, Varroa destructor (Anderson & Trueman) by the honeybee, Apis mellifera L, host and its environment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Transcript levels of vitellogenins (Vgs) in the varroa mite, Varroa destructor (Anderson & Trueman) were variably induced by interactions between the developing honeybee as a food source and the capped honeybee cell environment. Transcripts for 2 Vgs of varroa mites were sequenced and putative Vg pr...

  9. Clinical use of the combined Sclarovsky Birnbaum Severity and Anderson Wilkins Acuteness scores from the pre-hospital ECG in ST-segment elevation myocardial infarction.

    PubMed

    Fakhri, Yama; Schoos, Mikkel M; Clemmensen, Peter; Sejersten, Maria

    2014-01-01

    This review summarizes the electrocardiographic changes during an evolving ST segment elevation myocardial infarction and discusses associated electrocardiographic scores and the potential use of these indices in clinical practice, in particular the ECG scores developed by Anderson and Wilkins estimating the acuteness of myocardial ischemia and Sclarovsky-Birnbaum's grades of ischemia evaluating the severity of ongoing ischemia. PMID:24792905

  10. Examining the role of foraging and malvolio in host-finding behavior in the honey bee parasite, Varroa destructor (Anderson & Trueman)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    When a female varroa mite, Varroa destructor (Anderson & Trueman), invades a honey bee brood cell, the physiology rapidly changes from the feeding phoretic to reproductive. Changes in the foraging and malvolio transcript levels in the brain have been associated with modulated intra-specific food sea...

  11. Paleontological analysis of a lacustrine carbonaceous uranium deposit at the Anderson mine, Date Creek basin, west-central Arizona (U.S.A.)

    USGS Publications Warehouse

    Otton, J.K.; Bradbury, J.P.; Forester, R.M.; Hanley, J.H.

    1990-01-01

    The Tertiary sedimentary sequence of the Date Creek basin area of Arizona is composed principally of intertonguing alluvial-fan and lacustrine deposits. The lacustrine rocks contain large intermediate- to, locally, high-grade uranium deposits that form one of the largest uranium resources in the United States (an estimated 670,000 tons of U3O8 at an average grade of 0.023% is indicated by drilling to date). At the Anderson mine, about 50,000 tons of U3O8 occurs in lacustrine carbonaceous siltstones and mudstones (using a cutoff grade of 0.01%). The Anderson mine constitutes a new class of ore deposit, a lacustrine carbonaceous uranium deposit. Floral and faunal remains at the Anderson mine played a critical role in creating and documenting conditions necessary for uranium mineralization. Organic-rich, uraniferous rocks at the Anderson mine contain plant remains and ostracodes having remarkably detailed preservation of internal features because of infilling by opaline silica. This preservation suggests that the alkaline lake waters in the mine area contained high concentrations of dissolved silica and that silicification occurred rapidly, before compaction or cementation of the enclosing sediment. Uranium coprecipitated with the silica. Thinly laminated, dark-colored, siliceous beds contain centric diatoms preserved with carbonaceous material suggesting that lake waters at the mine were locally deep and anoxic. These alkaline, silica-charged waters and a stagnant, anoxic environment in parts of the lake were necessary conditions for the precipitation of large amounts of uranium in the lake-bottom sediments. Sediments at the Anderson mine contain plant remains and pollen that were derived from diverse vegetative zones suggesting about 1500 m of relief in the area at the time of deposition. The pollen suggests that the valley floor was semiarid and subtropical, whereas nearby mountains supported temperate deciduous forests. ?? 1990.

  12. Preliminary report on methodology for calculating coal resources of the Wyodak-Anderson coal zone, Powder River basin, Wyoming and Montana

    USGS Publications Warehouse

    Ellis, Margaret S.; Gunther, Gregory L.; Flores, Romeo M.; Stricker, Gary D.; Ochs, Allan M.; Schuenemeyer, John H.

    1998-01-01

    The National Coal Resource Assessment of the Wyodak-Anderson coal zone includes reports on the geology, stratigraphy, quality, and quantity of coal. The calculation of resources is only one aspect of the assessment. Without thorough documentation of the coal resource study and the methods used, the results of our study could be misinterpreted. The task of calculating coal resources included many steps, the use of several commercial software programs, and the incorporation of custom programs. The methods used for calculating coal resources for the Wyodak-Anderson coal zone vary slightly from the methods used in other study areas, and by other workers in the National Coal Resource Assessment. The Wyodak-Anderson coal zone includes up to 10 coal beds in any given location. The net coal thickness of the zone at each data point location was calculated by summing the thickness of all of the coal beds that were greater than 2.5 ft thick. The amount of interburden is not addressed or reported in this coal resource assessment. The amount of overburden reported is the amount of rock above the stratigraphically highest coal bed in the zone. The resource numbers reported do not include coal within mine or lease areas, in areas containing mapped Wyodak-Anderson clinker, or in areas where the coal is extrapolated to be less than 2.5 ft thick. The resources of the Wyodak-Anderson coal zone are reported in Ellis and others (1998). A general description of how the resources were calculated is included in that report. The purpose of this report is to document in more detail some of the parameters and methods used, define our spatial data, compare resources calculated using different grid options and calculation methods, and explain the application of confidence limits to the resource calculation.

  13. Your Menstrual Cycle

    MedlinePlus

    ... during your menstrual cycle What happens during your menstrual cycle The menstrual cycle includes not just your period, but the rise ... tool is based on a sample 28-day menstrual cycle, but every woman is different in how long ...

  14. Effet de l'interaction coulombienne sur la localisation d'Anderson dans le gaz bidimensionnel d'électrons

    NASA Astrophysics Data System (ADS)

    Fleury, G.

    2010-09-01

    Nous étudions l’effet des interactions coulombiennes sur la localisation d’Anderson dans le gaz bidimensionnel d’électrons désordonné. L’objectif est de statuer sur la question de l’existence de métaux à deux dimensions. En l’absence d’interaction, la théorie d’échelle de la localisation prédit qu’un désordre infinitésimal suffit à localiser la fonction d’onde électronique et donc à rendre le système isolant à température nulle (Abrahams et al., 1979). Dans certaines limites extrêmes, les interactions peuvent être prises en compte et l’on aboutit également à un état isolant. Cependant, aucune théorie analytique ne permet de traiter le régime quantique non-perturbatif où désordre et interaction sont intermédiaires. Expérimentalement, il est possible de l’explorer dans des échantillons de haute mobilité et basse densité. Depuis 1994, des comportements métalliques inexpliqués y ont été observés (Kravchenko et al., 1994). Nous avons mis au point une méthode numérique permettant d’étudier le problème couplé de la localisation d’Anderson en présence d’interaction. Cette méthode mêle Monte Carlo quantique à température nulle et théorie d’échelle pour la conductance de Thouless. Nous trouvons que la théorie d’échelle de la localisation est préservée en présence d’interaction et donc que le gaz bidimensionnel, même corrélé, est isolant à température nulle. Nos résultats montrent de plus que les interactions délocalisent le gaz bidimensionnel et que cet effet de délocalisation est accru en présence de dégénérescence de vallées. Ils nous permettent de proposer un mécanisme simple rendant compte des principales caractéristiques des comportements métalliques observés expérimentalement.

  15. pH-controlled assembly of hybrid architectures based on Anderson-type polyoxometalates and silver coordination units.

    PubMed

    Hu, Ying; An, Haiyan; Liu, Xuan; Yin, Jiqiu; Wang, Huilong; Zhang, Hua; Wang, Lin

    2014-02-14

    Three new architectures based on Anderson-type polyoxometalates, (3-H2pya)[(3-Hpya)2Ag][AgAlMo6H6O24]·3H2O 1, HNa2[(3-pya)(3-Hpya)Ag]2[AlMo6H6O24]·8H2O 2 and [(3-Hpya)2Ag][(H2O)2Ag]2[AlMo6H6O24]·2H2O 3 (3-Hpya = 3-(3-pyridyl)acrylic acid), have been synthesized at the different pH values and characterized by elemental analysis, IR spectroscopy, TG analysis, powder X-ray diffraction and single crystal X-ray diffraction. Compound 1 was obtained at lower pH value (2.50), and represents a 3D host-guest compound containing the Ag-3-Hpya coordination complex guest and the 3D [AgAlMo6H6O24](2-) host. The host framework exhibits a 4-connected diamond topology, and is constructed from [AlMo6H6O24](3-) clusters connected by Ag(+) cations. When the pH value was increased slightly, compound 2 was obtained with a 1D chain structure built up of Anderson polyoxoanions, Ag-3-Hpya coordination complexes and binuclear sodium clusters. By further increasing the pH value (3.50), compound 3 was isolated as a 2D network in which [AlMo6H6O24](3-) clusters are linked together by Ag(+) cations and Ag-3-Hpya coordination complexes. Their structural differences reveal that the pH value of the reaction system is the key factor influencing the structure and topology of three compounds. The UV-visible-NIR diffuse reflectivity spectra of 1-3 show that they can be regarded as a wide gap semiconductor. Furthermore, the pyrolysis of 1-3 produces three nanocomposites 1'-3' composed of silver microparticles dispersed in the metal oxides. The photocatalytic properties of 1'-3' have been investigated. PMID:24306316

  16. Temperature dependence of the zero-bias anomaly in the Anderson-Hubbard model: insights from an ensemble of two-site systems

    NASA Astrophysics Data System (ADS)

    Wortis, R.; Atkinson, W. A.

    2011-03-01

    Motivated by experiments on doped transition metal oxides, this paper considers the interplay of interactions, disorder, kinetic energy and temperature in a simple system. An ensemble of two-site Anderson-Hubbard model systems has already been shown to display a zero-bias anomaly (Wortis and Atkinson 2010 Phys. Rev. B 82 073107) which shares features with that found in the two-dimensional Anderson-Hubbard model (Chiesa et al 2008 Phys. Rev. Lett. 101 086401). Here the temperature dependence of the density of states of this ensemble is examined. In the atomic limit, there is no zero-bias anomaly at zero temperature, but one develops at small nonzero temperatures. With hopping, small temperatures augment the zero-temperature kinetic-energy-driven zero-bias anomaly, while at larger temperatures the anomaly is filled in.

  17. Transient phases and dynamical transitions in the post-quench evolution of the generalized Bose-Anderson model

    NASA Astrophysics Data System (ADS)

    Chichinadze, Dmitry V.; Ribeiro, Pedro; Shchadilova, Yulia E.; Rubtsov, Alexey N.

    2016-08-01

    The exact description of the time evolution of open correlated quantum systems remains one of the major challenges of condensed matter theory, especially for asymptotic long times where most numerical methods fail. Here, the post-quench dynamics of the N -component Bose-Anderson impurity model is studied in the N →∞ limit. The equilibrium phase diagram is similar to that of the Bose-Hubbard model in that it contains local versions of Mott and Bose phases. Using a numerically exact procedure, we are able to study the real-time evolution including asymptotic long-time regimes. The formation of long-lived transient phases is observed for quench paths crossing foreign phases. For quenches inside the local Bose condensed phase, a dynamical phase transition is reported that separates the evolution towards a new equilibrium state and a regime characterized at large times by a persistent phase rotation of the order parameter. We explain how such nondecaying modes can exist in the presence of a dissipative bath. We discuss the extension of our results to the experimental relevant finite-N case and their implication for the existence of nondecaying modes in generic quantum systems in the presence of a bath.

  18. Dynamics of the Anderson model for dilute magnetic alloys: A quantum Monte Carlo and maximum entropy study

    SciTech Connect

    Silver, R.N.; Gubernatis, J.E.; Sivia, D.S. ); Jarrell, M. . Dept. of Physics)

    1990-01-01

    In this article we describe the results of a new method for calculating the dynamical properties of the Anderson model. QMC generates data about the Matsubara Green's functions in imaginary time. To obtain dynamical properties, one must analytically continue these data to real time. This is an extremely ill-posed inverse problem similar to the inversion of a Laplace transform from incomplete and noisy data. Our method is a general one, applicable to the calculation of dynamical properties from a wide variety of quantum simulations. We use Bayesian methods of statistical inference to determine the dynamical properties based on both the QMC data and any prior information we may have such as sum rules, symmetry, high frequency limits, etc. This provides a natural means of combining perturbation theory and numerical simulations in order to understand dynamical many-body problems. Specifically we use the well-established maximum entropy (ME) method for image reconstruction. We obtain the spectral density and transport coefficients over the entire range of model parameters accessible by QMC, with data having much larger statistical error than required by other proposed analytic continuation methods.

  19. A Functional Generalization of the Field-Theoretical Renormalization Group Approach for the Single-Impurity Anderson Model

    NASA Astrophysics Data System (ADS)

    Freire, Hermann; Corrêa, Eberth

    2012-02-01

    We apply a functional implementation of the field-theoretical renormalization group (RG) method up to two loops to the single-impurity Anderson model. To achieve this, we follow a RG strategy similar to that proposed by Vojta et al. (in Phys. Rev. Lett. 85:4940, 2000), which consists of defining a soft ultraviolet regulator in the space of Matsubara frequencies for the renormalized Green's function. Then we proceed to derive analytically and solve numerically integro-differential flow equations for the effective couplings and the quasiparticle weight of the present model, which fully treat the interplay of particle-particle and particle-hole parquet diagrams and the effect of the two-loop self-energy feedback into them. We show that our results correctly reproduce accurate numerical renormalization group data for weak to slightly moderate interactions. These results are in excellent agreement with other functional Wilsonian RG works available in the literature. Since the field-theoretical RG method turns out to be easier to implement at higher loops than the Wilsonian approach, higher-order calculations within the present approach could improve further the results for this model at stronger couplings. We argue that the present RG scheme could thus offer a possible alternative to other functional RG methods to describe electronic correlations within this model.

  20. Nailing the Coffin Shut on Doubts that Violent Video Games Stimulate Aggression ∼Comment on Anderson et al. (2010).

    PubMed Central

    Huesmann, L. Rowell

    2010-01-01

    Over the past half-century the mass media, including video games, have become important socializers of children. Observational learning theory has evolved into social-cognitive information processing models that explain that what a child observes in any venue has both short-term and long-term influences on the child's behaviors and cognitions. Anderson's (2010) extensive meta-analysis of the effects of violent video games confirms what these theories predict and what prior research about other violent mass media has found – that violent video games stimulate aggression in the players in the short run and increase the risk for aggressive behaviors by the players later in life. The effects occur for males and females and for children growing up in Eastern or Western cultures. The effects are strongest for the best studies. Contrary to some critics' assertions, the meta-analysis is methodologically sound and comprehensive. Yet the results are unlikely to change the critics' views or the public's perception that the issue is undecided because there are some studies that have yielded null effects, because many people are concerned that the implications of the research threaten freedom of expression, and because many people have their identities or self-interests closely tied to violent video games. PMID:20192555

  1. Microwave conductance in random waveguides in the cross-over to Anderson localization and single-parameter scaling

    PubMed Central

    Shi, Zhou; Wang, Jing; Genack, Azriel Z.

    2014-01-01

    The nature of transport of electrons and classical waves in disordered systems depends upon the proximity to the Anderson localization transition between freely diffusing and localized waves. The suppression of average transport and the enhancement of relative fluctuations in conductance in one-dimensional samples with lengths greatly exceeding the localization length, , are related in the single-parameter scaling (SPS) theory of localization. However, the difficulty of producing an ensemble of statistically equivalent samples in which the electron wave function is temporally coherent has so-far precluded the experimental demonstration of SPS. Here we demonstrate SPS in random multichannel systems for the transmittance T of microwave radiation, which is the analog of the dimensionless conductance. We show that for , a single eigenvalue of the transmission matrix (TM) dominates transmission, and the distribution of the is Gaussian with a variance equal to the average of , as conjectured by SPS. For samples in the cross-over to localization, , we find a one-sided distribution for . This anomalous distribution is explained in terms of a charge model for the eigenvalues of the TM τ in which the Coulomb interaction between charges mimics the repulsion between the eigenvalues of TM. We show in the localization limit that the joint distribution of T and the effective number of transmission eigenvalues determines the probability distributions of intensity and total transmission for a single-incident channel. PMID:24516156

  2. Surface hopping with a manifold of electronic states. II. Application to the many-body Anderson-Holstein model

    SciTech Connect

    Dou, Wenjie; Subotnik, Joseph E.; Nitzan, Abraham

    2015-02-28

    We investigate a simple surface hopping (SH) approach for modeling a single impurity level coupled to a single phonon and an electronic (metal) bath (i.e., the Anderson-Holstein model). The phonon degree of freedom is treated classically with motion along–and hops between–diabatic potential energy surfaces. The hopping rate is determined by the dynamics of the electronic bath (which are treated implicitly). For the case of one electronic bath, in the limit of small coupling to the bath, SH recovers phonon relaxation to thermal equilibrium and yields the correct impurity electron population (as compared with numerical renormalization group). For the case of out of equilibrium dynamics, SH current-voltage (I-V) curve is compared with the quantum master equation (QME) over a range of parameters, spanning the quantum region to the classical region. In the limit of large temperature, SH and QME agree. Furthermore, we can show that, in the limit of low temperature, the QME agrees with real-time path integral calculations. As such, the simple procedure described here should be useful in many other contexts.

  3. [The nephropathy in the Anderson-Fabry disease: new recommendations for the diagnosis, the follow-up and the therapy].

    PubMed

    Mignani, Renzo; Gallieni, Maurizio; Feriozzi, Sandro; Pisani, Antonio; Marziliano, Nicola; Morrone, Amelia

    2015-01-01

    Anderson-Fabry disease is a rare X-linked lysosomal storage disorder caused by mutations of the GLA gene that encodes alpha-galactosidase A. It is a characterized by the involvement of several systems: renal, neurological, hearth, cochleovestibular and cutaneous systems are the most involved. Despite recent studies have provided new insights in the this disease, there are still lacks and discrepancies among all insiders regarding the diagnosis, clinical and therapeutic management. Enzyme replacement have been demonstrated to improve the course of the disease, especially when the diagnosis is early. There are still some debates on diagnosis and management of patients, in particular in the heterozygote female and the start of enzyme replacement. Thus, an Italian board, composed by nephrologists, cardiologists, genetics, pediatricians and neurologists has been established in order to approve through a consensus a diagnostic and therapeutic Italian management. Authors report the renal clinical and therapeutic management, a useful tool either for expert physicians or for those with a few experience in the diagnosis and management of this disease. PMID:26252265

  4. Spin-current Seebeck effect in an interacting quantum dot: Atomic approximation for the Anderson impurity model

    NASA Astrophysics Data System (ADS)

    Ramos, E.; Silva-Valencia, J.; Franco, R.; Siqueira, E. C.; Figueira, M. S.

    2015-11-01

    We study the spin-current Seebeck effect through an immersed gate defined quantum dot, employing the U-finite atomic method for the single impurity Anderson model. Our description qualitatively confirms some of the results obtained by an earlier Hartree-Fock work, but as our calculation includes the Kondo effect, some new features will appear in the spin-current Seebeck effect S, which as a function of the gate voltage present an oscillatory shape. At intermediate temperatures, our results show a three zero structure and at low temperatures, our results are governed by the emergence of the Kondo peak in the transmittance, which defines the behavior of the shape of the S coefficient as a function of the parameters of the model. The oscillatory behavior obtained by the Hartree-Fock approximation reproduces the shape obtained by us in a non-interacting system (U=0). The S sign is sensitive to different polarization of the quantum dot, and as a consequence the device could be employed to experimentally detect the polarization states of the system. Our results also confirm that the large increase of S upon increasing U, obtained by the mean field approximation, is correct only for low temperatures. We also discuss the role of the Kondo peak in defining the behavior of the spin thermopower at low temperatures.

  5. Renormalization group flow of the Luttinger-Ward functional: Conserving approximations and application to the Anderson impurity model

    NASA Astrophysics Data System (ADS)

    Rentrop, J. F.; Meden, V.; Jakobs, S. G.

    2016-05-01

    We study the renormalization group flow of the Luttinger-Ward functional and of its two-particle-irreducible vertex functions, given a cutoff in the two-particle interaction. We derive a conserving approximation to the flow and relate it to the fluctuation exchange approximation as well as to nonconserving approximations introduced in an earlier publication [J. F. Rentrop, S. G. Jakobs, and V. Meden, J. Phys. A: Math. Theor. 48, 145002 (2015), 10.1088/1751-8113/48/14/145002]. We apply the different approximate flow equations to the single-impurity Anderson model in thermal equilibrium at vanishing temperature. Numerical results for the effective mass, the spin susceptibility, the charge susceptibility, and the linear conductance reflect the similarity of the methods to the fluctuation exchange approximation. We find the majority of the approximations to deviate stronger from the exact results than one-particle-irreducible functional renormalization group schemes. However, we identify a simple static two-particle-irreducible flow scheme which performs remarkably well and produces an exponential Kondo-like scale in the renormalized level position.

  6. Local and Regional Staging of Invasive Breast Cancer With Sonography: 25 Years of Practice at MD Anderson Cancer Center

    PubMed Central

    2014-01-01

    At The University of Texas MD Anderson Cancer Center, we have used sonography (US) extensively for more than 2 decades to refine the local and regional staging of invasive breast cancer. Although magnetic resonance imaging is superior to all other imaging modalities in the measurement of the primary tumor and detection of additional foci of malignancy, in our experience US has shown sufficient accuracy in clinical practice to stage most invasive breast cancers. The exceptions are ill-defined tumors such as invasive lobular cancers and tumors in breasts containing extensive diffuse benign disease. An advantage of US is that multifocality or multicentricity can be confirmed via US-guided fine-needle aspiration within 15 minutes and the information shared immediately with the patient and the breast surgeon or medical oncologist. US has also proved indispensable in the evaluation of lymphatic spread because it can evaluate more nodal basins (e.g., the supraclavicular fossa and low neck) than magnetic resonance imaging can and because it can guide needle biopsy to confirm the status of any indeterminate node (including internal mammary nodes) within minutes. PMID:24309983

  7. No correlation between Anderson Reservoir stage level and underlying Calaveras fault seismicity despite calculated differential stress increases

    USGS Publications Warehouse

    Parsons, T.

    2011-01-01

    Concerns have been raised that stresses from reservoir impoundment may trigger damaging earthquakes because rate changes have been associated with reservoir impoundment or stage-level changes globally. Here, the idea is tested blindly using Anderson Reservoir, which lies atop the seismically active Calaveras fault. The only knowledge held by the author going into the study was the expectation that reservoir levels change cyclically because of seasonal rainfall. Examination of seismicity rates near the reservoir reveals variability, but no correlation with stage-level changes. Three-dimensional fi nite-element modeling shows stress changes suffi cient for earthquake triggering along the Calaveras fault zone. Since many of the reported cases of induced triggering come from low-strain settings, it is speculated that gradual stressing from stage-level changes in high-strain settings may not be signifi cant. From this study, it can be concluded that reservoirs are not necessarily risky in active tectonic settings. ?? 2011 Geological Society of America.

  8. Genomic organization and reproductive regulation of a large lipid transfer protein in the varroa mite, Varroa destructor (Anderson & Trueman).

    PubMed

    Cabrera, A R; Shirk, P D; Duehl, A J; Donohue, K V; Grozinger, C M; Evans, J D; Teal, P E A

    2013-10-01

    The complete genomic region and corresponding transcript of the most abundant protein in phoretic varroa mites, Varroa destructor (Anderson & Trueman), were sequenced and have homology with acarine hemelipoglycoproteins and the large lipid transfer protein (LLTP) super family. The genomic sequence of VdLLTP included 14 introns and the mature transcript coded for a predicted polypeptide of 1575 amino acid residues. VdLLTP shared a minimum of 25% sequence identity with acarine LLTPs. Phylogenetic assessment showed VdLLTP was most closely related to Metaseiulus occidentalis vitellogenin and LLTP proteins of ticks; however, no heme binding by VdLLTP was detected. Analysis of lipids associated with VdLLTP showed that it was a carrier for free and esterified C12 -C22 fatty acids from triglycerides, diacylglycerides and monoacylglycerides. Additionally, cholesterol and β-sitosterol were found as cholesterol esters linked to common fatty acids. Transcript levels of VdLLTP were 42 and 310 times higher in phoretic female mites when compared with males and quiescent deutonymphs, respectively. Coincident with initiation of the reproductive phase, VdLLTP transcript levels declined to a third of those in phoretic female mites. VdLLTP functions as an important lipid transporter and should provide a significant RNA interference target for assessing the control of varroa mites. PMID:23834736

  9. Quantum criticality of the two-channel pseudogap Anderson model: universal scaling in linear and non-linear conductance.

    PubMed

    Wu, Tsan-Pei; Wang, Xiao-Qun; Guo, Guang-Yu; Anders, Frithjof; Chung, Chung-Hou

    2016-05-01

    The quantum criticality of the two-lead two-channel pseudogap Anderson impurity model is studied. Based on the non-crossing approximation (NCA) and numerical renormalization group (NRG) approaches, we calculate both the linear and nonlinear conductance of the model at finite temperatures with a voltage bias and a power-law vanishing conduction electron density of states, [Formula: see text] (0  <  r  <  1) near the Fermi energy [Formula: see text]. At a fixed lead-impurity hybridization, a quantum phase transition from the two-channel Kondo (2CK) to the local moment (LM) phase is observed with increasing r from r  =  0 to [Formula: see text]. Surprisingly, in the 2CK phase, different power-law scalings from the well-known [Formula: see text] or [Formula: see text] form is found. Moreover, novel power-law scalings in conductances at the 2CK-LM quantum critical point are identified. Clear distinctions are found on the critical exponents between linear and non-linear conductance at criticality. The implications of these two distinct quantum critical properties for the non-equilibrium quantum criticality in general are discussed. PMID:27045815

  10. Quantum criticality of the two-channel pseudogap Anderson model: universal scaling in linear and non-linear conductance

    NASA Astrophysics Data System (ADS)

    Wu, Tsan-Pei; Wang, Xiao-Qun; Guo, Guang-Yu; Anders, Frithjof; Chung, Chung-Hou

    2016-05-01

    The quantum criticality of the two-lead two-channel pseudogap Anderson impurity model is studied. Based on the non-crossing approximation (NCA) and numerical renormalization group (NRG) approaches, we calculate both the linear and nonlinear conductance of the model at finite temperatures with a voltage bias and a power-law vanishing conduction electron density of states, {ρ\\text{c}}(ω )\\propto |ω -{μ\\text{F}}{{|}r} (0  <  r  <  1) near the Fermi energy {μ\\text{F}} . At a fixed lead-impurity hybridization, a quantum phase transition from the two-channel Kondo (2CK) to the local moment (LM) phase is observed with increasing r from r  =  0 to r={{r}\\text{c}}<1 . Surprisingly, in the 2CK phase, different power-law scalings from the well-known \\sqrt{T} or \\sqrt{V} form is found. Moreover, novel power-law scalings in conductances at the 2CK-LM quantum critical point are identified. Clear distinctions are found on the critical exponents between linear and non-linear conductance at criticality. The implications of these two distinct quantum critical properties for the non-equilibrium quantum criticality in general are discussed.

  11. Phylogeny and biogeography of the Anderson's crocodile newt, Echinotriton andersoni (Amphibia: Caudata), as revealed by mitochondrial DNA sequences.

    PubMed

    Honda, Masanao; Matsui, Masafumi; Tominaga, Atsushi; Ota, Hidetoshi; Tanaka, Satoshi

    2012-11-01

    The Anderson's crocodile newt, Echinotriton andersoni, is considered a relic and endangered species distributed in the Central Ryukyus. To elucidate phylogenetic relationships and detailed genetic structures among populations, we analyzed variation in the mitochondrial cytochrome b gene. Results strongly support a primary dichotomy between populations from the Amami and Okinawa Island Groups with substantial genetic divergence, favoring a primary divergence between the two island groups. Within the latter, populations from the southern part of Okinawajima Island are shown to be more closely related to those from Tokashikijima Island than to those from the northern and central parts of Okinawajima. The prominent genetic divergence between the two island groups of the Central Ryukyus seems to have initiated in the Miocene, i.e., prior to formation of the strait that has consistently separated these island groups since the Pleistocene. The ancestor of the southern Okinawajima-Tokashikijima is estimated to have migrated from the northern and central parts of Okinawajima into southern Okinawajima at the Pleistocene, and dispersed into Tokashikijima subsequently. PMID:22846685

  12. Density matrix renormalization group study in energy space for a single-impurity Anderson model and an impurity quantum phase transition

    NASA Astrophysics Data System (ADS)

    Shirakawa, Tomonori; Yunoki, Seiji

    2016-05-01

    The density matrix renormalization group method is introduced in energy space to study Anderson impurity models. The method allows for calculations in the thermodynamic limit and is advantageous for studying not only the dynamical properties, but also the quantum entanglement of the ground state at the vicinity of an impurity quantum phase transition. This method is applied to obtain numerically exactly the ground-state phase diagram of the single-impurity Anderson model on the honeycomb lattice at half-filling. The calculation of local static quantities shows that the phase diagram contains two distinct phases, the local moment (LM) phase and the asymmetric strong coupling (ASC) phase, but no Kondo screening phase. These results are supported by the local spin and charge excitation spectra, which exhibit qualitatively different behavior in these two phases and also reveal the existence of the valence fluctuating point at the phase boundary. For comparison, we also study the low-energy effective pseudogap Anderson model using the method introduced here. Although the high-energy excitations are obviously different, we find that the ground-state phase diagram and the asymptotically low-energy excitations are in good quantitative agreement with those for the single-impurity Anderson model on the honeycomb lattice, thus providing a quantitative justification for the previous studies based on low-energy approximate approaches. Furthermore, we find that the lowest entanglement level is doubly degenerate for the LM phase, whereas it is singlet for the ASC phase and is accidentally threefold degenerate at the valence fluctuating point. This should be contrasted with the degeneracy of the energy spectrum because the ground state is found to be always singlet. Our results therefore clearly demonstrate that the low-lying entanglement spectrum can be used to determine with high accuracy the phase boundary of the impurity quantum phase transition.

  13. Sulfur and ash in paleocene Wyodak-Anderson coal in the Powder River Basin, Wyoming and Montana: A fuel source beyond 2000

    SciTech Connect

    Ellis, M.S.; Stricker, G.D.; Flores, R.M.; Bader, L.R.

    1998-04-01

    When coal-fired power plants are required by the Environmental Protection Agency (EPA) to meet more stringent sulfur emission standards (0.6 pound per million Btu) after the year 2000, most of the clean and compliant coals will come from the Powder River Basin in Wyoming and Montana. In 1996 more than 300 million short tons of these clean and compliant coals were produced from the Paleocene Fort Union Formation in the northern Rocky Mountains and Great Plains region. This is more than 30 percent of the total US coal production of 1.03 billion short tons in 1996. Future demand for clean and compliant coals can probably be met through production of more Fort Union coals in the region. It is projected by the Energy Information Agency (1996) that most of the low-sulfur and low-ash coals in the northern Rocky Mountains and Great Plains region will be produced from the Wyodak-Anderson coal bed/zone of the Paleocene Fort Union Formation in the Powder River Basin. To date, coal produced from the Wyodak-Anderson coal bed/zone, containing 0.5 percent sulfur, 1.2 lb SO{sub 2} per million btu, and 6 percent ash (mean values on an as-received basis) meet current EPA regulatory compliance. This coal bed/zone alone produced 262 million short tons or >26 percent of the total U.S. coal production in 1996. Based on the current consumption rates of coal and a forecast by the EIA (1996), the Wyodak-Anderson coals are projected to produce an additional 153 million short tons a year by the year 2016. At this rate of production, high quality Wyodak-Anderson coals may be adequate to fill our future energy needs.

  14. Sulfur and ash in Paleocene Wyodak-Anderson coal in the Powder River Basin, Wyoming and Montana: A fuel source beyond 2000

    SciTech Connect

    Ellis, M.S.; Stricker, G.D.; Flores, R.M.; Bader, L.R.

    1998-07-01

    When coal-fired power plants are required by the Environmental Protection Agency (EPA) to meet more stringent sulfur emission standards (0.6 pound per million Btu) after the year 2000, most of the clean and compliant coals will come from the Powder River Basin in Wyoming and Montana. In 1996 more than 300 million short toms of these clean and compliant coals were produced from the Paleocene Fort Union Formation in the northern Rocky Mountains and Great Plans region. This is more than 30% of the total US coal production of 1.03 billion short tons in 1996. Future demand for clean and compliant coals can probably be met through production of more F or Union coals in the region. It is projected by the Energy Information Agency (1996) that most of the low-sulfur and low-ash coals in the northern Rocky Mountains and Great Plains region will be produced from the Wyodak-Anderson coal bed/zone of the Paleocene Fort Union Formation in the Powder River Basin. To date, coal produced from the Wyodak-Anderson coal bed/zone, containing 0.5% sulfur, 1.2 lb SO{sub 2} per million btu, and 6% ash (mean values on an as-received basis) meet current EPA regulatory compliance. This coal bed/zone alone produced 262 million short toms of >26% of the total US coal production in 1996. Based on the current consumption rates of coal and a forecast by the EIA (1996), the Wyodak-Anderson coals are projected to produce an additional 153 million short tons a year by the year 2016. At this rate of production, high quality Wyodak-Anderson coals may be adequate to fill future energy needs.

  15. Hydrological cycle.

    PubMed

    Gonçalves, H C; Mercante, M A; Santos, E T

    2011-04-01

    The Pantanal hydrological cycle holds an important meaning in the Alto Paraguay Basin, comprising two areas with considerably diverse conditions regarding natural and water resources: the Plateau and the Plains. From the perspective of the ecosystem function, the hydrological flow in the relationship between plateau and plains is important for the creation of reproductive and feeding niches for the regional biodiversity. In general, river declivity in the plateau is 0.6 m/km while declivity on the plains varies from 0.1 to 0.3 m/km. The environment in the plains is characteristically seasonal and is home to an exuberant and abundant diversity of species, including some animals threatened with extinction. When the flat surface meets the plains there is a diminished water flow on the riverbeds and, during the rainy season the rivers overflow their banks, flooding the lowlands. Average annual precipitation in the Basin is 1,396 mm, ranging from 800 mm to 1,600 mm, and the heaviest rainfall occurs in the plateau region. The low drainage capacity of the rivers and lakes that shape the Pantanal, coupled with the climate in the region, produce very high evaporation: approximately 60% of all the waters coming from the plateau are lost through evaporation. The Alto Paraguay Basin, including the Pantanal, while boasting an abundant availability of water resources, also has some spots with water scarcity in some sub-basins, at different times of the year. Climate conditions alone are not enough to explain the differences observed in the Paraguay River regime and some of its tributaries. The complexity of the hydrologic regime of the Paraguay River is due to the low declivity of the lands that comprise the Mato Grosso plains and plateau (50 to 30 cm/km from east to west and 3 to 1.5 cm/km from north to south) as well as the area's dimension, which remains periodically flooded with a large volume of water. PMID:21537597

  16. Systematics and the origin of species from the viewpoint of a botanist: edgar anderson prepares the 1941 jesup lectures with ernst mayr.

    PubMed

    Kleinman, Kim

    2013-01-01

    The correspondence between Edgar Anderson and Ernst Mayr leading into their 1941 Jesup Lectures on "Systematics and the Origin of Species" addressed population thinking, the nature of species, the relationship of microevolution to macroevolution, and the evolutionary dynamics of plants and animals, all central issues in what came to be known as the Evolutionary Synthesis. On some points, they found ready agreement; for others they forged only a short term consensus. They brought two different working styles to this project reflecting their different appreciations of what was possible at this point in evolutionary studies. For Mayr, it was a focused project with definitive short term conclusions imminent while Anderson viewed it as an episode in an ongoing historical process that, while exciting and suggestive, remained openended. Thus, Mayr and Anderson represent two distinct perspectives on the Evolutionary Synthesis in formation; by understanding both of their points of view, we can grasp more fully the state of evolutionary theory at this key moment. PMID:22684268

  17. Much ado about nothing: the misestimation and overinterpretation of violent video game effects in eastern and western nations: comment on Anderson et al. (2010).

    PubMed

    Ferguson, Christopher J; Kilburn, John

    2010-03-01

    The issue of violent video game influences on youth violence and aggression remains intensely debated in the scholarly literature and among the general public. Several recent meta-analyses, examining outcome measures most closely related to serious aggressive acts, found little evidence for a relationship between violent video games and aggression or violence. In a new meta-analysis, C. A. Anderson et al. (2010) questioned these findings. However, their analysis has several methodological issues that limit the interpretability of their results. In their analysis, C. A. Anderson et al. included many studies that do not relate well to serious aggression, an apparently biased sample of unpublished studies, and a "best practices" analysis that appears unreliable and does not consider the impact of unstandardized aggression measures on the inflation of effect size estimates. They also focused on bivariate correlations rather than better controlled estimates of effects. Despite a number of methodological flaws that all appear likely to inflate effect size estimates, the final estimate of r = .15 is still indicative of only weak effects. Contrasts between the claims of C. A. Anderson et al. (2010) and real-world data on youth violence are discussed. PMID:20192554

  18. Reduced Right Ventricular Native Myocardial T1 in Anderson-Fabry Disease: Comparison to Pulmonary Hypertension and Healthy Controls

    PubMed Central

    Pagano, Joseph J.; Chow, Kelvin; Khan, Aneal; Michelakis, Evangelos; Paterson, Ian; Oudit, Gavin Y.; Thompson, Richard B.

    2016-01-01

    Aims Anderson-Fabry disease (AFD) is characterized by progressive multiorgan accumulation of intracellular sphingolipids due to α-galactosidase A enzyme deficiency, resulting in progressive ventricular hypertrophy, heart failure, arrhythmias, and death. Decreased native (non-contrast) left ventricular (LV) T1 (longitudinal relaxation time) with MRI discriminates AFD from healthy controls or other presentations of concentric hypertrophy, but the right ventricle (RV) has not been studied. The aims of the current study were to evaluate native RV T1 values in AFD, with a goal of better understanding the pathophysiology of RV involvement. Methods and Results Native T1 values were measured in the inferior RV wall (RVI), interventricular septum (IVS), and inferior LV (LVI) in patients with AFD, patients with pulmonary hypertension, who provided an alternative RV pathological process for comparison, and healthy controls. A minimum wall thickness of 4 mm was selected to minimize partial volume errors in tissue T1 analysis. T1 analysis was performed in 6 subjects with AFD, 6 subjects with PH, and 21 controls. Native T1 values were shorter (adjusted p<0.05 for all comparisons), independent of location, in subjects with AFD (RVI-T1 = 1096±49 ms, IVS-T1 = 1053±41 ms, LVI-T1 = 1072±44 ms) compared to both PH (RVI-T1 = 1239±41 ms, IVS-T1 = 1280±123 ms, LVI-T1 = 1274±57 ms) and HC (IVS-T1 = 1180±60 ms, LVI-T1 = 1183±45 ms). RVI measurements were not possible in controls due to insufficient wall thickness. Conclusion Native T1 values appear similarly reduced in the left and right ventricles of individuals with AFD and RV wall thickening, suggesting a common pathology. In contrast, individuals with PH and thickened RVs showed increased native T1 values in both ventricles, suggestive of fibrosis. PMID:27305064

  19. Linguistic Validation of the Turkish Version of the M.D. Anderson Symptom Inventory - Head and Neck Cancer Module

    PubMed Central

    Brandon Gunn, G.; Atalar, Banu; Mendoza, Tito R.; Cleeland, Charles S.; Selek, Uğur; Özyar, Enis; Rosenthal, David I.

    2016-01-01

    Background: The use of patient symptom reports with frequent symptom assessment may be preferred over the more commonly used health-related quality of life questionnaires. Aims: We sought to linguistically validate the Turkish version of the M.D. Anderson Symptom Inventory-Head and Neck module (MDASI-HN) patient reported outcome questionnaire. Study Design: Validation study. Methods: Following standard forward and backward translation of the original and previously validated English MDASI-HN into a Turkish version (T-MDASI-HN), it was administered to patients with head and neck cancer able to read and understand Turkish. Patients were then cognitively debriefed to evaluate their understanding and comprehension of the T-MDASI-HN. Individual and group responses are presented using descriptive statistics. Results: Twenty-six participants with head and neck cancer completed the T-MDASIHN and accompanying cognitive debriefing. Overall, 97 percent of the individual TMDASI-HN items were completed. Average recorded time to complete the 28 item TMDASI-HN questionnaire was 5.4 minutes (range 2–10). Average overall ease of completion, understandability, and acceptability were favorably rated at 1.0, 1.1, and 0.2, respectively, on scales from 0 to 10. Only 5 of the 26 of participants reported trouble completing any single questionnaire items, namely the “difficulty remembering” item for 3 individuals. Conclusion: The T-MDASI-HN is linguistically valid with ease of completion, relevance, comprehensibility, and applicability and it can be a useful clinical and research tool. PMID:27308079

  20. Solar Cycle 23: An Anomalous Cycle?

    NASA Astrophysics Data System (ADS)

    de Toma, G.; White, O. R.; Chapman, G. A.; Walton, S. R.; Preminger, D. G.; Cookson, A. M.

    2004-05-01

    We discuss the importance of solar cycle 23 as a magnetically simpler cycle and a variant from recent cycles. We see a significant decrease in sunspot activity in cycle 23 relative to cycle 22, but the strength of the total solar irradiance (TSI) cycle did not change significantly. The latest SOHO/VIRGO TSI time series is analyzed using new solar variability measures obtained from full-disk solar images made at the San Fernando Observatory and the MgII 280nm index. The TSI record for the period 1986 to the present is reproduced within about 130ppm RMS using only two indices representing photospheric and chromospheric sources of variability due to magnetic regions. This is in spite of the difference in magnetic activity between the two cycles. Our results show the continuing improvement in TSI measurements and surrogates containing information necessary to account for irradiance variability.

  1. A Scientific Synthesis and Assessment of the Arctic Carbon Cycle

    NASA Astrophysics Data System (ADS)

    Hayes, Daniel J.; Guo, Laodong; McGuire, A. David

    2007-06-01

    The Arctic Monitoring and Assessment Programme (AMAP), along with the Climate and Cryosphere (CliC) Project and the International Arctic Science Committee (IASC), sponsored the Arctic Carbon Cycle Assessment Workshop, at the Red Lion Hotel in Seattle, Wash., between 27 February and 1 March 2007. The workshop was held in a general effort toward the scientific synthesis and assessment of the Arctic system carbon cycle, as well as to generate feedback on the working draft of an assessment document. The initial assessment was prepared by the Arctic carbon cycle assessment writing team, which is led by A. David McGuire (University of Alaska Fairbanks) and includes Leif Anderson (Goteborg University, Sweden), Torben Christensen (Lund University, Sweden), Scott Dallimore (Natural Resources Canada), Laodong Guo (University of Southern Mississippi), Martin Heimann (Max Planck Institute, Germany), Robie MacDonald (Department of Fisheries and Oceans, Canada), and Nigel Roulet (McGill University, Canada). The workshop brought together leading researchers in the fields of terrestrial, marine, and atmospheric science to report on and discuss the current state of knowledge on contemporary carbon stocks and fluxes in the Artie and their potential responses to a changing climate. The workshop was attended by 35 scientists representing institutions from 10 countries in addition to two representatives of the sponsor agencies (John Calder for AMAP and Diane Verseghy for CliC).

  2. Solar Cycle 23: An Anomalous Cycle?

    NASA Astrophysics Data System (ADS)

    de Toma, Giuliana; White, Oran R.; Chapman, Gary A.; Walton, Stephen R.; Preminger, Dora G.; Cookson, Angela M.

    2004-07-01

    The latest SOHO VIRGO total solar irradiance (TSI) time series is analyzed using new solar variability measures obtained from full-disk solar images made at the San Fernando Observatory and the Mg II 280 nm index. We discuss the importance of solar cycle 23 as a magnetically simpler cycle and a variant from recent cycles. Our results show the continuing improvement in TSI measurements and surrogates containing information necessary to account for irradiance variability. Use of the best surrogate for irradiance variability due to photospheric features (sunspots and faculae) and chromospheric features (plages and bright network) allows fitting the TSI record to within an rms difference of 130 ppm for the period 1986 to the present. Observations show that the strength of the TSI cycle did not change significantly despite the decrease in sunspot activity in cycle 23 relative to cycle 22. This points to the difficulty of modeling TSI back to times when only sunspot observations were available.

  3. Quantum dissipative effects on non-equilibrium transport through a single-molecular transistor: The Anderson-Holstein-Caldeira-Leggett model

    NASA Astrophysics Data System (ADS)

    Raju, Ch. Narasimha; Chatterjee, Ashok

    2016-01-01

    The Anderson-Holstein model with Caldeira-Leggett coupling with environment is considered to describe the damping effect in a single molecular transistor (SMT) which comprises a molecular quantum dot (with electron-phonon interaction) mounted on a substrate (environment) and coupled to metallic electrodes. The electron-phonon interaction is first eliminated using the Lang-Firsov transformation and the spectral density function, charge current and differential conductance are then calculated using the non-equilibrium Keldysh Green function technique. The effects of damping rate, and electron-electron and electron-phonon interactions on the transport properties of SMT are studied at zero temperature.

  4. Quantum dissipative effects on non-equilibrium transport through a single-molecular transistor: The Anderson-Holstein-Caldeira-Leggett model.

    PubMed

    Raju, Ch Narasimha; Chatterjee, Ashok

    2016-01-01

    The Anderson-Holstein model with Caldeira-Leggett coupling with environment is considered to describe the damping effect in a single molecular transistor (SMT) which comprises a molecular quantum dot (with electron-phonon interaction) mounted on a substrate (environment) and coupled to metallic electrodes. The electron-phonon interaction is first eliminated using the Lang-Firsov transformation and the spectral density function, charge current and differential conductance are then calculated using the non-equilibrium Keldysh Green function technique. The effects of damping rate, and electron-electron and electron-phonon interactions on the transport properties of SMT are studied at zero temperature. PMID:26732725

  5. Quantum dissipative effects on non-equilibrium transport through a single-molecular transistor: The Anderson-Holstein-Caldeira-Leggett model

    PubMed Central

    Raju, Ch. Narasimha; Chatterjee, Ashok

    2016-01-01

    The Anderson-Holstein model with Caldeira-Leggett coupling with environment is considered to describe the damping effect in a single molecular transistor (SMT) which comprises a molecular quantum dot (with electron-phonon interaction) mounted on a substrate (environment) and coupled to metallic electrodes. The electron-phonon interaction is first eliminated using the Lang-Firsov transformation and the spectral density function, charge current and differential conductance are then calculated using the non-equilibrium Keldysh Green function technique. The effects of damping rate, and electron-electron and electron-phonon interactions on the transport properties of SMT are studied at zero temperature. PMID:26732725

  6. Popular culture and sporting life in the rural margins of late eighteenth-century England: the world of Robert Anderson, "The Cumberland Bard".

    PubMed

    Huggins, Mike

    2012-01-01

    This study sets out to extend and challenge existing historiography on late eighteenth century British popular culture, customary sports, class and cultural identity, focusing upon the rural geo-political borderland of England. It suggests that prevailing class-based and more London-biased studies need to be balanced with more regionalist-based work, and shows the importance of northern regional leisure variants. The textual and historical analysis draws largely on the published works of a neglected working-class dialect poet, Robert Anderson, living and working in Cumberland, arguing that he represented a strain of ''bardic regionalism,'' a variant of Katie Trumpener’s ''bardic nationalism.'' PMID:22400156

  7. Solar Cycle 25: Another Moderate Cycle?

    NASA Astrophysics Data System (ADS)

    Cameron, R. H.; Jiang, J.; Schüssler, M.

    2016-06-01

    Surface flux transport simulations for the descending phase of Cycle 24 using random sources (emerging bipolar magnetic regions) with empirically determined scatter of their properties provide a prediction of the axial dipole moment during the upcoming activity minimum together with a realistic uncertainty range. The expectation value for the dipole moment around 2020 (2.5 ± 1.1 G) is comparable to that observed at the end of Cycle 23 (about 2 G). The empirical correlation between the dipole moment during solar minimum and the strength of the subsequent cycle thus suggests that Cycle 25 will be of moderate amplitude, not much higher than that of the current cycle. However, the intrinsic uncertainty of such predictions resulting from the random scatter of the source properties is considerable and fundamentally limits the reliability with which such predictions can be made before activity minimum is reached.

  8. Hypobetalipoproteinemia with accumulation of an apoprotein B-like protein in intestinal cells. Immunoenzymatic and biochemical characterization of seven cases of Anderson's disease.

    PubMed Central

    Bouma, M E; Beucler, I; Aggerbeck, L P; Infante, R; Schmitz, J

    1986-01-01

    We describe here seven cases (from five kindreds) of Anderson's disease, which is characterized by diarrhea, steatorrhea, hypobetalipoproteinemia with low levels of cholesterol, triglycerides, and phospholipids, and failure to secrete chylomicrons after a fat meal. Enterocytes isolated from intestinal biopsies of patients after overnight fast showed numerous fat droplets, a histological picture resembling that of abetalipoproteinemia. Immunoenzymatic staining of the enterocytes demonstrated large amounts of material that reacted with a polyclonal antiserum to apolipoprotein B. Further, the immunoreactive material was found to react with several different monoclonal antibodies capable of recognizing both the B100 and B48 forms of apoprotein B, but not with any of several monoclonal antibodies capable of recognizing only B100. This suggests that the material in the enterocytes is the B48 form of apoprotein B or a fragment thereof. Additional findings included decreased low density lipoprotein levels with an abnormal chemical composition, abnormal high density lipoprotein2 (HDL2) and HDL3 particle size distributions, and an abnormal HDL apoprotein composition. Increased amounts of proteins having electrophoretic mobilities similar to apo E and the E-AII complex were present. Finally, some cases exhibited additional protein components of apparent molecular weights between 17,000 and 28,000, which was similar to some cases of abetalipoproteinemia. These findings demonstrate that Anderson's disease is not due to the absence of synthesis of intestinal apo B and suggest that it is more complex than previously thought, affecting all the lipoprotein classes. Images PMID:2426307

  9. Ocean Color and the Equatorial Annual Cycle in the Pacific

    NASA Astrophysics Data System (ADS)

    Hammann, A. C.; Gnanadesikan, A.

    2012-12-01

    The presence of chlorophyll, colored dissolved organic matter (CDOM) and other scatterers in ocean surface waters affect the flux divergence of solar radiation and thus the vertical distribution of radiant heating of the ocean. While this may directly alter the local mixed-layer depth and temperature (Martin 1985; Strutton & Chavez 2004), non-local changes are propagated through advection (Manizza et al. 2005; Murtugudde et al. 2002; Nakamoto et al. 2001; Sweeny et al. 2005). In and coupled feedbacks (Lengaigne et al. 2007; Marzeion & Timmermann 2005). Anderson et al. (2007), Anderson et al. (2009) and Gnanadesikan & Anderson (2009) have performed a series of experiments with a fully coupled climate model which parameterizes the e-folding depth of solar irradiance in terms of surface chlorophyll-a concentration. The results have so far been discussed with respect to the climatic mean state and ENSO variability in the tropical Pacific. We extend the discussion here to the Pacific equatorial annual cycle. The focus of the coupled experiments has been the sensitivity of the coupled system to regional differences in chlorophyll concentration. While runs have been completed with realistic SeaWiFS-derived monthly composite chlorophyll ('green') and with a globally chlorophyll-free ocean ('blue'), the concentrations in two additional runs have been selectively set to zero in specific regions: the oligotrophic subtropical gyres ('gyre') in one case and the mesotrophic gyre margins ('margin') in the other. The annual cycle of ocean temperatures exhibits distinctly reduced amplitudes in the 'blue' and 'margin' experiments, and a slight reduction in 'gyre' (while ENSO variability almost vanishes in 'blue' and 'gyre', but amplifies in 'margin' - thus the frequently quoted inverse correlation between ENSO and annual amplitudes holds only for the 'green' / 'margin' comparison). It is well-known that on annual time scales, the anomalous divergence of surface currents and vertical

  10. Cycling To Awareness.

    ERIC Educational Resources Information Center

    Kozak, Stan

    1999-01-01

    Encourages environmental and outdoor educators to promote bicycling. In the community and the curriculum, cycling connects environmental issues, health and fitness, law and citizenship, appropriate technology, and the joy of being outdoors. Describes the Ontario Cycling Association's cycling strategy and its four components: school cycling…

  11. HIV Life Cycle

    MedlinePlus

    HIV Overview The HIV Life Cycle (Last updated 9/8/2016; last reviewed 9/8/2016) Key Points HIV gradually destroys the immune ... life cycle. What is the connection between the HIV life cycle and HIV medicines? Antiretroviral therapy (ART) ...

  12. Why the Learning Cycle?

    ERIC Educational Resources Information Center

    Marek, Edmund A.

    2008-01-01

    The learning cycle is a way to structure inquiry in school science and occurs in several sequential phases. A learning cycle moves children through a scientific investigation by having them first explore materials, then construct a concept, and finally apply or extend the concept to other situations. Why the learning cycle? Because it is a…

  13. Introduction to combined cycles

    NASA Astrophysics Data System (ADS)

    Moore, M. J.

    Ideas and concepts underlying the technology of combined cycles including the scientific principles involved and the reasons these cycles are in fashion at the present time, are presented. A cycle is a steady flow process for conversion of heat energy into work, in which a working medium passes through a range of states, returning to its original state. Cycles for power production are the steam cycle, which is a closed cycle, and the gas turbine, which represents an open cycle. Combined cycle thermodynamic parameters, are discussed. The general arrangement of the plant is outlined and important features of their component parts described. The scope for future development is discussed. It is concluded that for the next few years the natural gas fired combined cycle will be the main type of plant installed for electricity generation and cogeneration. Whilst gas turbines may not increase substantially in unit size, there remains scope for further increase in firing temperature with consequent increase in cycle performance. However the larger global reserves of coal are providing an incentive to the development of plant for clean coal combustion using the inherent advantage of the combined cycle to attain high efficiencies.

  14. The major ion, 87Sr/86Sr, and δ11B geochemistry of groundwater in the Wyodak-Anderson coal bed aquifer (Powder River Basin, Wyoming, USA)

    NASA Astrophysics Data System (ADS)

    Lemarchand, Damien; Jacobson, Andrew D.; Cividini, Damien; Chabaux, François

    2015-11-01

    We developed a multicomponent, 1D advective transport model that describes the downgradient evolution of solute concentrations, 87Sr/86Sr ratios, and δ11B values in the Wyodak-Anderson Coal Bed (WACB) aquifer located in the Powder River Basin, Wyoming, USA. The purpose of the study was to evaluate the chemical vulnerability of groundwater to potential environmental change stemming from the extraction of coal bed methane and shale gas. Model calculations demonstrate that coupling between microbial activity and the dissolved carbonate system controls major ion transport in the WACB aquifer. The analysis of 87Sr/86Sr ratios further reveals the importance of ion-exchange reactions. Similarly, δ11B data emphasize the significance of pH-dependent surface reactions and demonstrate the vulnerability of the aquifer to the long-term acidification of recharge water.

  15. Quantum evolution: The case of weak localization for a 3D alloy-type Anderson model and application to Hamiltonian based quantum computation

    NASA Astrophysics Data System (ADS)

    Cao, Zhenwei

    Over the years, people have found Quantum Mechanics to be extremely useful in explaining various physical phenomena from a microscopic point of view. Anderson localization, named after physicist P. W. Anderson, states that disorder in a crystal can cause non-spreading of wave packets, which is one possible mechanism (at single electron level) to explain metal-insulator transitions. The theory of quantum computation promises to bring greater computational power over classical computers by making use of some special features of Quantum Mechanics. The first part of this dissertation considers a 3D alloy-type model, where the Hamiltonian is the sum of the finite difference Laplacian corresponding to free motion of an electron and a random potential generated by a sign-indefinite single-site potential. The result shows that localization occurs in the weak disorder regime, i.e., when the coupling parameter lambda is very small, for energies E ≤ --Clambda 2. The second part of this dissertation considers adiabatic quantum computing (AQC) algorithms for the unstructured search problem to the case when the number of marked items is unknown. In an ideal situation, an explicit quantum algorithm together with a counting subroutine are given that achieve the optimal Grover speedup over classical algorithms, i.e., roughly speaking, reduce O(2n) to O(2n/2), where n is the size of the problem. However, if one considers more realistic settings, the result shows this quantum speedup is achievable only under a very rigid control precision requirement (e.g., exponentially small control error).

  16. Low cycle fatigue

    NASA Technical Reports Server (NTRS)

    Solomon, H. D. (Editor); Kaisand, L. R. (Editor); Halford, G. R. (Editor); Leis, B. N. (Editor)

    1988-01-01

    The papers contained in this volume focus on various aspects of low cycle fatigue, including cyclic deformation, crack propagation, high-temperature low cycle fatigue, microstructural defects, multiaxial and variable amplitude loading, and life prediction. Papers are presented on the low cycle fatigue of some aluminum alloys, prediction of crack growth under creep-fatigue loading conditions, high-temperature low cycle fatigue behavior and lifetime prediction of a nickel-base ODS alloy, and an integrated approach to creep-fatigue life prediction. Other topics discussed include thermal fatigue testing of coated monocrystalline superalloys, low cycle fatigue of Al-Mg-Si alloys, and the effect of superimposed stresses at high frequency on low cycle fatigue.

  17. [Cycling in Zagreb].

    PubMed

    Matos, Stipan; Krapac, Ladislav; Krapac, Josip

    2007-01-01

    Cycling in Zagreb, as means of urban transport inside and outside the city, has a bright past, hazy presence but a promising future. Every day, aggressive citizens who lack urban traffic culture mistreat many cyclists but also many pedestrians. Sedentary way of living, unhealthy eating habits and inadequate recreation would surely be reduced if Zagreb had a network of cycling tracks (190 cm) or lanes (80 cm). Main city roads were constructed at the beginning of the 20th century. Today, the lack of cycling tracks is particularly evident in terms of missing connections between northern and southern parts of the city. Transportation of bikes in public vehicles, parking of bikes as well as cycling along the foot of the mountains Medvednica and Zumberacko gorje is not adequately organized. Better organization is necessary not only because of the present young generation but also because of the young who will shortly become citizens of the EU, where cycling is enormously popular. Cycling tourism is not known in Zagreb, partly due to inadequate roads. The surroundings of Zagreb are more suitable for cycling tourism and attractive brochures and tourist guides offer information to tourists on bikes. Professional, acrobatic and sports cycling do not have a tradition in Zagreb and in Croatia. The same holds true for recreational cycling and indoor exercise cycling. The authors discuss the impact of popularization of cycling using print and electronic media. The role of district and local self-government in the construction and improvement of traffic roads in Zagreb is very important. It is also significant for the implementation of legal regulations that must be obeyed by all traffic participants in order to protect cyclists, the most vulnerable group of traffic participants besides passengers. Multidisciplinary action of all benevolent experts would surely increase safety and pleasure of cycling in the city and its surroundings. This would also help reduce daily stress and

  18. Solar activity secular cycles

    NASA Astrophysics Data System (ADS)

    Kramynin, A. P.; Mordvinov, A. V.

    2013-12-01

    Long-term variations in solar activity secular cycles have been studied using a method for the expansion of reconstructed sunspot number series Sn( t) for 11400 years in terms of natural orthogonal functions. It has been established that three expansion components describe more than 98% of all Sn( t) variations. In this case, the contribution of the first expansion component is about 92%. The averaged form of the 88year secular cycle has been determined based on the form of the first expansion coordinate function. The quasi-periodicities modulating the secular cycle have been revealed based on the time function conjugate to the first function. The quasi-periodicities modulating the secular cycle coincide with those observed in the Sn( t) series spectrum. A change in the secular cycle form and the time variations in this form are described by the second and third expansion components, the contributions of which are about 4 and 2%, respectively. The variations in the steepness of the secular cycle branches are more pronounced in the 200-year cycle, and the secular cycle amplitude varies more evidently in the 2300-year cycle.

  19. Nuclear fuel cycle costs

    SciTech Connect

    Burch, W.D.; Haire, M.J.; Rainey, R.H.

    1982-02-01

    The costs for the back-end of the nuclear fuel cycle, which were developed as part of the Nonproliferation Alternative Systems Assessment Program (NASAP), are presented. Total fuel cycle costs are given for the pressurized water reactor once-through and fuel recycle systems, and for the liquid-metal fast breeder reactor system. These calculations show that fuel cycle costs are a small part of the total power costs. For breeder reactors, fuel cycle costs are about half that of the present once-through system. The total power cost of the breeder reactor system is greater than that of light-water reactor at today's prices for uranium and enrichment.

  20. Reusable thermal cycling clamp

    NASA Technical Reports Server (NTRS)

    Debnam, W. J., Jr.; Fripp, A. L.; Crouch, R. K. (Inventor)

    1985-01-01

    A reusable metal clamp for retaining a fused quartz ampoule during temperature cycling in the range of 20 deg C to 1000 deg C is described. A compressible graphite foil having a high radial coefficient of thermal expansion is interposed between the fused quartz ampoule and metal clamp to maintain a snug fit between these components at all temperature levels in the cycle.

  1. Seeing the Carbon Cycle

    ERIC Educational Resources Information Center

    Drouin, Pamela; Welty, David J.; Repeta, Daniel; Engle-Belknap, Cheryl A.; Cramer, Catherine; Frashure, Kim; Chen, Robert

    2006-01-01

    In this article, the authors present a classroom experiment that was developed to introduce middle school learners to the carbon cycle. The experiment deals with transfer of CO[subscript 2] between liquid reservoirs and the effect CO[subscript 2] has on algae growth. It allows students to observe the influence of the carbon cycle on algae growth,…

  2. The Oxygen Cycle.

    ERIC Educational Resources Information Center

    Swant, Gary D.

    Produced for primary grades, this booklet provides study of the oxygen-carbon dioxide cycle in nature. Line drawings, a minimum amount of narrative, and a glossary of terms make up its content. The booklet is designed to be used as reading material, a coloring book, or for dramatic arts with students acting out parts of the cycle. This work was…

  3. Rock Cycle Roulette.

    ERIC Educational Resources Information Center

    Schmidt, Stan M.; Palmer, Courtney

    2000-01-01

    Introduces an activity on the rock cycle. Sets 11 stages representing the transitions of an earth material in the rock cycle. Builds six-sided die for each station, and students move to the stations depending on the rolling side of the die. Evaluates students by discussing several questions in the classroom. Provides instructional information for…

  4. Measuring Cycling Effort.

    ERIC Educational Resources Information Center

    Jahnke, Thomas; Hamson, Mike

    1999-01-01

    Investigates the basic mechanics of cycling with a simple reckoning of how much effort is needed from the cyclist. The work done by the cyclist is quantified when the ride is on the flat and also when pedaling uphill. Proves that by making use of the available gears on a mountain bike, cycling uphill can be accomplished without pain. (Author/ASK)

  5. The carbon cycle revisited

    NASA Technical Reports Server (NTRS)

    Bolin, Bert; Fung, Inez

    1992-01-01

    Discussions during the Global Change Institute indicated a need to present, in some detail and as accurately as possible, our present knowledge about the carbon cycle, the uncertainties in this knowledge, and the reasons for these uncertainties. We discuss basic issues of internal consistency within the carbon cycle, and end by summarizing the key unknowns.

  6. Family Life Cycle: 1980.

    ERIC Educational Resources Information Center

    Norton, Arthur J.

    1983-01-01

    Used data from a 1980 national sample survey to show differences in the timing of major family life-cycle events according to age, social and economic characteristics, and marital history. Results suggest that age generational differences, more than any other factor, influence timing of life-cycle events. (Author/JAC)

  7. Power Plant Cycling Costs

    SciTech Connect

    Kumar, N.; Besuner, P.; Lefton, S.; Agan, D.; Hilleman, D.

    2012-07-01

    This report provides a detailed review of the most up to date data available on power plant cycling costs. The primary objective of this report is to increase awareness of power plant cycling cost, the use of these costs in renewable integration studies and to stimulate debate between policymakers, system dispatchers, plant personnel and power utilities.

  8. Teaching the Krebs Cycle.

    ERIC Educational Resources Information Center

    Akeroyd, F. Michael

    1983-01-01

    Outlines a simple but rigorous treatment of the Krebs Cycle suitable for A-level Biology students. The importance of the addition of water molecules in various stages of the cycle is stressed as well as the removal of hydrogen atoms by the oxidizing enzymes. (JN)

  9. Predicting the Sunspot Cycle

    NASA Technical Reports Server (NTRS)

    Hathaway, David H.

    2009-01-01

    The 11-year sunspot cycle was discovered by an amateur astronomer in 1844. Visual and photographic observations of sunspots have been made by both amateurs and professionals over the last 400 years. These observations provide key statistical information about the sunspot cycle that do allow for predictions of future activity. However, sunspots and the sunspot cycle are magnetic in nature. For the last 100 years these magnetic measurements have been acquired and used exclusively by professional astronomers to gain new information about the nature of the solar activity cycle. Recently, magnetic dynamo models have evolved to the stage where they can assimilate past data and provide predictions. With the advent of the Internet and open data policies, amateurs now have equal access to the same data used by professionals and equal opportunities to contribute (but, alas, without pay). This talk will describe some of the more useful prediction techniques and reveal what they say about the intensity of the upcoming sunspot cycle.

  10. The Chlamydomonas Cell Cycle

    PubMed Central

    Cross, Frederick R.; Umen, James G.

    2015-01-01

    The position of Chlamydomonas within the eukaryotic phylogeny makes it a unique model in at least two important ways: as a representative of the critically important, early-diverging lineage leading to plants, and as a microbe retaining important features of the last eukaryotic common ancestor (LECA) that have been lost in the highly studied yeast lineages. Its cell biology has been studied for many decades, and it has well-developed experimental genetic tools, both classical (Mendelian) and molecular. Unlike land plants, it is a haploid with very few gene duplicates, making it ideal for loss-of-function genetic studies. The Chlamydomonas cell cycle has a striking temporal and functional separation between cell growth and rapid cell divisions, probably connected to the interplay between diurnal cycles that drive photosynthetic cell growth with the cell division cycle; it also exhibits a highly choreographed interaction between the cell cycle and its centriole/basal body/flagellar cycle. Here we review the current status of studies of the Chlamydomonas cell cycle. We begin with an overview of cell cycle control in the well-studied yeast and animal systems, which has yielded a canonical, well-supported model. We discuss briefly what is known about similarities and differences in plant cell cycle control compared to this model. We next review the cytology and cell biology of the multiple fission cell cycle of Chlamydomonas. Lastly we review recent genetic approaches and insights into Chlamydomonas cell cycle regulation that have been enabled by a new generation of genomics-based tools. PMID:25690512

  11. Which 100-kyr Cycle?

    NASA Astrophysics Data System (ADS)

    Berger, A.; Loutre, M. F.; Mélice, J. L.

    The origin of all the fundamental frequencies characterising the long term variations of the astronomical parameters has been identified. This allows to discuss their inter- relationship and possible changes in times. Different sources for the so-called 100-kyr cycle have been found in the astronomical parameters and in the insolation itself. The most popular 100-kyr cycle is certainly the eccentricity one. Actually, the periods of the most important spectral components of e used in Berger (1978) are 412 885, 14 945, 123 297, 99 590 and 131 248 yr. Instability of the resulting average 100-kyr cy- cle has been shown related to the ~ 400-kyr cycle. The derivative of eccentricity is definitely showing a spectrum dominated by the 100-kyr cycle with the same spectral components as e itself. The inclination of the Earth orbital plane on the ecliptic does not display any 100-kyr cycle, but it is not the case for its inclination on the reference plane for which cycles of 98 046 and 107 478 years appear. Finally the frequency modulation of obliquity is characterised by cycles 171 kyr and 97 kyr long. For inso- lation, it is known that there is only a very weak signal around 100-kyr coming from e itself. However, if we consider the seasonal cycle at the equator, its amplitude varies with cycles of 400 kyr, 100 kyr, 41 kyr, 10 kyr and 5 kyr, all related to e. Although all these cycles are close to the 100 kyr cycle found in geological data, the origin of this kind of cycle can be best identified by comparing the proxy record to the re- sponse of the climate system to the astronomical forcing. This forcing signal which contains, in one way or another, the astronomical characteristics mentioned above is, at least, partly distorted and transformed, a modification which can only be estimated through climate models. Such a climate model has been developed in the early 80Ss in Louvain-la-Neuve and used since to simulate the last and next glacial-interglacial cycles.

  12. Bimodality and the Hale cycle

    NASA Technical Reports Server (NTRS)

    Wilson, Robert M.

    1988-01-01

    Evidence is provided of a modulation of between 20 and 24 yr for the Hale cycle, and comparison of consecutive pairs of cycles strongly suggests that even-numbered cycles are preferentially paired with odd-numbered following cycles. The results indicate that cycles 22 and 23 form a new cyle pair. The sum of monthly mean sunspot numbers over consecutively paired sunspot cycles for Hale cycle 12 is found to be about 19,100 + or - 3000.

  13. Applied physiology of cycling.

    PubMed

    Faria, I E

    1984-01-01

    Historically, the bicycle has evolved through the stages of a machine for efficient human transportation, a toy for children, a finely-tuned racing machine, and a tool for physical fitness development, maintenance and testing. Recently, major strides have been made in the aerodynamic design of the bicycle. These innovations have resulted in new land speed records for human powered machines. Performance in cycling is affected by a variety of factors, including aerobic and anaerobic capacity, muscular strength and endurance, and body composition. Bicycle races range from a 200m sprint to approximately 5000km. This vast range of competitive racing requires special attention to the principle of specificity of training. The physiological demands of cycling have been examined through the use of bicycle ergometers, rollers, cycling trainers, treadmill cycling, high speed photography, computer graphics, strain gauges, electromyography, wind tunnels, muscle biopsy, and body composition analysis. These techniques have been useful in providing definitive data for the development of a work/performance profile of the cyclist. Research evidence strongly suggests that when measuring the cyclist's aerobic or anaerobic capacity, a cycling protocol employing a high pedalling rpm should be used. The research bicycle should be modified to resemble a racing bicycle and the cyclist should wear cycling shoes. Prolonged cycling requires special nutritional considerations. Ingestion of carbohydrates, in solid form and carefully timed, influences performance. Caffeine appears to enhance lipid metabolism. Injuries, particularly knee problems which are prevalent among cyclists, may be avoided through the use of proper gearing and orthotics. Air pollution has been shown to impair physical performance. When pollution levels are high, training should be altered or curtailed. Effective training programmes simulate competitive conditions. Short and long interval training, blended with long

  14. The Rock Cycle

    ERIC Educational Resources Information Center

    Singh, Raman J.; Bushee, Jonathan

    1977-01-01

    Presents a rock cycle diagram suitable for use at the secondary or introductory college levels which separates rocks formed on and below the surface, includes organic materials, and separates products from processes. (SL)

  15. Mining the Learning Cycle.

    ERIC Educational Resources Information Center

    Hemler, Debra; King, Hobart

    1996-01-01

    Describes an approach that uses the learning cycle to meaningfully teach students about mineral properties while alleviating the tedious nature of identifying mineral specimens. Discusses mineral properties, cooperative learning, and mineral identification. (JRH)

  16. Life Cycle Costing.

    ERIC Educational Resources Information Center

    McCraley, Thomas L.

    1985-01-01

    Life cycle costing establishes a realistic comparison of the cost of owning and operating products. The formula of initial cost plus maintenance plus operation divided by useful life identifies the best price over the lifetime of the product purchased. (MLF)

  17. The global carbon cycle

    SciTech Connect

    Sedjo, R.A. )

    1990-10-01

    The author discusses the global carbon cycle and cites the results of several recently completed research projects, that seem to indicate that the temperate zone forests are a sink for carbon rather than a source, as was previously believed.

  18. Solar Cycle Prediction

    NASA Technical Reports Server (NTRS)

    Pesnell, William Dean

    2011-01-01

    Solar cycle predictions are needed to plan long-term space missions; just like weather predictions are needed to plan your next vacation. Fleets of satellites circle the Earth collecting many types of science data, protecting astronauts, and relaying information. All of these satellites are sensitive at some level to solar cycle effects. Predictions of drag on LEO spacecraft are one of the most important. Launching a satellite with less propellant can mean a higher orbit, but unanticipated solar activity and increased drag can make that a Pyrrhic victory. Energetic events at the Sun can produce crippling radiation storms that endanger all assets in space. Testing solar dynamo theories by quantitative predictions of what will happen in 5-20 years is the next arena for solar cycle predictions. I will describe the current state of solar cycle predictions and anticipate how those predictions could be made more accurate in the future.

  19. Cycle isolation monitoring

    SciTech Connect

    Svensen, L.M. III; Zeigler, J.R.; Todd, F.D.; Alder, G.C.

    2009-07-15

    There are many factors to monitor in power plants, but one that is frequently overlooked is cycle isolation. Often this is an area where plant personnel can find 'low hanging fruit' with great return on investment, especially high energy valve leakage. This type of leakage leads to increased heat rate, potential valve damage and lost generation. The fundamental question to ask is 'What is 100 Btu/kW-hr of heat rate worth to your plant? On a 600 MW coal-fired power plant, a 1% leakage can lead to an 81 Btu/kW-hr impact on the main steam cycle and a 64 Btu/kW-hr impact on the hot reheat cycle. The article gives advice on methods to assist in detecting leaking valves and to monitor cycle isolation. A software product, TP. Plus-CIM was designed to estimate flow rates of potentially leaking valves.

  20. Solar Cycle Predictions

    NASA Technical Reports Server (NTRS)

    Pesnell, William Dean

    2012-01-01

    Solar cycle predictions are needed to plan long-term space missions; just like weather predictions are needed to plan the launch. Fleets of satellites circle the Earth collecting many types of science data, protecting astronauts, and relaying information. All of these satellites are sensitive at some level to solar cycle effects. Predictions of drag on LEO spacecraft are one of the most important. Launching a satellite with less propellant can mean a higher orbit, but unanticipated solar activity and increased drag can make that a Pyrrhic victory as you consume the reduced propellant load more rapidly. Energetic events at the Sun can produce crippling radiation storms that endanger all assets in space. Solar cycle predictions also anticipate the shortwave emissions that cause degradation of solar panels. Testing solar dynamo theories by quantitative predictions of what will happen in 5-20 years is the next arena for solar cycle predictions. A summary and analysis of 75 predictions of the amplitude of the upcoming Solar Cycle 24 is presented. The current state of solar cycle predictions and some anticipations how those predictions could be made more accurate in the future will be discussed.

  1. Malone cycle refrigerator development

    SciTech Connect

    Shimko, M.A.; Crowley, C.J.

    1999-07-01

    This paper describes the progress made in demonstrating a Malone Cycle Refrigerator/Freezer. The Malone cycle is similar to the Stirling cycle but uses a supercritical fluid in place of real gas. In the approach, solid-metal diaphragms are used to seal and sweep the working volumes against the high working fluid pressures required in Malone cycle machines. This feature eliminates the friction and leakage that accounted for nearly half the losses in the best piston-defined Malone cycle machines built to date. The authors successfully built a Malone cycle refrigerator that: (1) used CO{sub 2} as the working fluid, (2) operated at pressures up to 19.3 Mpa (2,800 psi), (3) achieved a cold end metal temperatures of {minus}29 C ({minus}20 F), and (4) produced over 400 Watts of cooling at near ambient temperatures. The critical diaphragm components operated flawlessly throughout characterization and performance testing, supporting the conclusion of high reliability based on analysis of fatigue date and actual strain measurements.

  2. Quantifying the Adaptive Cycle

    PubMed Central

    Angeler, David G.; Allen, Craig R.; Garmestani, Ahjond S.; Gunderson, Lance H.; Hjerne, Olle; Winder, Monika

    2015-01-01

    The adaptive cycle was proposed as a conceptual model to portray patterns of change in complex systems. Despite the model having potential for elucidating change across systems, it has been used mainly as a metaphor, describing system dynamics qualitatively. We use a quantitative approach for testing premises (reorganisation, conservatism, adaptation) in the adaptive cycle, using Baltic Sea phytoplankton communities as an example of such complex system dynamics. Phytoplankton organizes in recurring spring and summer blooms, a well-established paradigm in planktology and succession theory, with characteristic temporal trajectories during blooms that may be consistent with adaptive cycle phases. We used long-term (1994–2011) data and multivariate analysis of community structure to assess key components of the adaptive cycle. Specifically, we tested predictions about: reorganisation: spring and summer blooms comprise distinct community states; conservatism: community trajectories during individual adaptive cycles are conservative; and adaptation: phytoplankton species during blooms change in the long term. All predictions were supported by our analyses. Results suggest that traditional ecological paradigms such as phytoplankton successional models have potential for moving the adaptive cycle from a metaphor to a framework that can improve our understanding how complex systems organize and reorganize following collapse. Quantifying reorganization, conservatism and adaptation provides opportunities to cope with the intricacies and uncertainties associated with fast ecological change, driven by shifting system controls. Ultimately, combining traditional ecological paradigms with heuristics of complex system dynamics using quantitative approaches may help refine ecological theory and improve our understanding of the resilience of ecosystems. PMID:26716453

  3. Price-Anderson Act Amendments Act of 1985. Hearing before the Subcommittee on Energy Research and Development of the Committee on Energy and Natural Resources, United States Senate, Ninety-Ninth Congress, First Session on S. 1225, June 25, 1985

    SciTech Connect

    Not Available

    1986-01-01

    A hearing on S. 1225, which clarifies and expands insurance coverage under the Price-Anderson Act, brought testimony from Nuclear Regulatory Commissioners, representatives of several states and power companies, insurance underwriters, and DOE. At issue was DOE's recommended changes to limit liability and to include commercial and defense waste facilities under the provisions for special coverage in event of an extraordinary nuclear occurrence. DOE's request was to update, but not to radically change the Price-Anderson Act. Utilities and insurance underwriters objected to policies which would impose heavier financial burdens on the nuclear power industry by requiring insurance pools. Witnesses noted the adverse effects of unlimited liability as well as the need to insure the health of the insurance industry in conjunction with promoting nuclear power. The testimony of 17 witnesses and additional responses for the record follows the text of S. 1225.

  4. Transport through an Anderson impurity: Current ringing, nonlinear magnetization, and a direct comparison of continuous-time quantum Monte Carlo and hierarchical quantum master equations

    NASA Astrophysics Data System (ADS)

    Härtle, R.; Cohen, G.; Reichman, D. R.; Millis, A. J.

    2015-08-01

    We give a detailed comparison of the hierarchical quantum master equation (HQME) method to a continuous-time quantum Monte Carlo (CT-QMC) approach, assessing the usability of these numerically exact schemes as impurity solvers in practical nonequilibrium calculations. We review the main characteristics of the methods and discuss the scaling of the associated numerical effort. We substantiate our discussion with explicit numerical results for the nonequilibrium transport properties of a single-site Anderson impurity. The numerical effort of the HQME scheme scales linearly with the simulation time but increases (at worst exponentially) with decreasing temperature. In contrast, CT-QMC is less restricted by temperature at short times, but in general the cost of going to longer times is also exponential. After establishing the numerical exactness of the HQME scheme, we use it to elucidate the influence of different ways to induce transport through the impurity on the initial dynamics, discuss the phenomenon of coherent current oscillations, known as current ringing, and explain the nonmonotonic temperature dependence of the steady-state magnetization as a result of competing broadening effects. We also elucidate the pronounced nonlinear magnetization dynamics, which appears on intermediate time scales in the presence of an asymmetric coupling to the electrodes.

  5. How mathematical epidemiology became a field of biology: a commentary on Anderson and May (1981) ‘The population dynamics of microparasites and their invertebrate hosts’

    PubMed Central

    Heesterbeek, J. A. P.; Roberts, M. G.

    2015-01-01

    We discuss the context, content and importance of the paper ‘The population dynamics of microparasites and their invertebrate hosts’, by R. M. Anderson and R. M. May, published in the Philosophical Transactions of the Royal Society as a stand-alone issue in 1981. We do this from the broader perspective of the study of infectious disease dynamics, rather than the specific perspective of the dynamics of insect pathogens. We argue that their 1981 paper fits seamlessly in the systematic study of infectious disease dynamics that was initiated by the authors in 1978, combining effective use of simple mathematical models, firmly rooted in biology, with observable or empirically measurable ingredients and quantities, and promoting extensive capacity building. This systematic approach, taking ecology and biology rather than applied mathematics as the motivation for advance, proved essential for the maturation of the field, and culminated in their landmark textbook of 1991. This commentary was written to celebrate the 350th anniversary of the journal Philosophical Transactions of the Royal Society. PMID:25750231

  6. Helium process cycle

    DOEpatents

    Ganni, Venkatarao

    2008-08-12

    A unique process cycle and apparatus design separates the consumer (cryogenic) load return flow from most of the recycle return flow of a refrigerator and/or liquefier process cycle. The refrigerator and/or liquefier process recycle return flow is recompressed by a multi-stage compressor set and the consumer load return flow is recompressed by an independent consumer load compressor set that maintains a desirable constant suction pressure using a consumer load bypass control valve and the consumer load return pressure control valve that controls the consumer load compressor's suction pressure. The discharge pressure of this consumer load compressor is thereby allowed to float at the intermediate pressure in between the first and second stage recycle compressor sets. Utilizing the unique gas management valve regulation, the unique process cycle and apparatus design in which the consumer load return flow is separate from the recycle return flow, the pressure ratios of each recycle compressor stage and all main pressures associated with the recycle return flow are allowed to vary naturally, thus providing a naturally regulated and balanced floating pressure process cycle that maintains optimal efficiency at design and off-design process cycle capacity and conditions automatically.

  7. Helium process cycle

    DOEpatents

    Ganni, Venkatarao

    2007-10-09

    A unique process cycle and apparatus design separates the consumer (cryogenic) load return flow from most of the recycle return flow of a refrigerator and/or liquefier process cycle. The refrigerator and/or liquefier process recycle return flow is recompressed by a multi-stage compressor set and the consumer load return flow is recompressed by an independent consumer load compressor set that maintains a desirable constant suction pressure using a consumer load bypass control valve and the consumer load return pressure control valve that controls the consumer load compressor's suction pressure. The discharge pressure of this consumer load compressor is thereby allowed to float at the intermediate pressure in between the first and second stage recycle compressor sets. Utilizing the unique gas management valve regulation, the unique process cycle and apparatus design in which the consumer load return flow is separate from the recycle return flow, the pressure ratios of each recycle compressor stage and all main pressures associated with the recycle return flow are allowed to vary naturally, thus providing a naturally regulated and balanced floating pressure process cycle that maintains optimal efficiency at design and off-design process cycle capacity and conditions automatically.

  8. Solar magnetic cycle

    NASA Technical Reports Server (NTRS)

    Harvey, Karen L.

    1993-01-01

    Using NSO/KP magnetograms, the pattern and rate of the emergence of magnetic flux and the development of the large-scale patterns of unipolar fields are considered in terms of the solar magnetic cycle. Magnetic flux emerges in active regions at an average rate of 2 x 10(exp 21) Mx/day, approximately 10 times the estimated rate in ephemeral regions. Observations are presented that demonstrate that the large-scale unipolar fields originate in active regions and activity nests. For cycle 21, the net contribution of ephemeral regions to the axial dipole moment of the Sun is positive, and is of opposite sign to that of active regions. Its amplitude is smaller by a factor of 6, assuming an average lifetime of ephemeral regions of 8 hours. Active regions larger than 4500 Mm(sup 2) are the primary contributor to the cycle variation of Sun's axial dipole moment.

  9. The global sulfur cycle

    NASA Technical Reports Server (NTRS)

    Sagan, D. (Editor)

    1985-01-01

    The results of the planetary biology microbial ecology's 1984 Summer Research Program, which examined various aspects of the global sulfur cycle are summarized. Ways in which sulfur flows through the many living and chemical species that inhabit the surface of the Earth were investigated. Major topics studied include: (1) sulfur cycling and metabolism of phototropic and filamentous sulfur bacteria; (2) sulfur reduction in sediments of marine and evaporite environments; (3) recent cyanobacterial mats; (4) microanalysis of community metabolism in proximity to the photic zone in potential stromatolites; and (5) formation and activity of microbial biofilms on metal sulfides and other mineral surfaces. Relationships between the global sulfur cycle and the understanding of the early evolution of the Earth and biosphere and current processes that affect global habitability are stressed.

  10. Superfluid thermodynamic cycle refrigerator

    DOEpatents

    Swift, Gregory W.; Kotsubo, Vincent Y.

    1992-01-01

    A cryogenic refrigerator cools a heat source by cyclically concentrating and diluting the amount of .sup.3 He in a single phase .sup.3 He-.sup.4 He solution. The .sup.3 He in superfluid .sup.4 He acts in a manner of an ideal gas in a vacuum. Thus, refrigeration is obtained using any conventional thermal cycle, but preferably a Stirling or Carnot cycle. A single phase solution of liquid .sup.3 He at an initial concentration in superfluid .sup.4 He is contained in a first variable volume connected to a second variable volume through a superleak device that enables free passage of .sup.4 He while restricting passage of .sup.3 He. The .sup.3 He is compressed (concentrated) and expanded (diluted) in a phased manner to carry out the selected thermal cycle to remove heat from the heat load for cooling below 1 K.

  11. Superfluid thermodynamic cycle refrigerator

    DOEpatents

    Swift, G.W.; Kotsubo, V.Y.

    1992-12-22

    A cryogenic refrigerator cools a heat source by cyclically concentrating and diluting the amount of [sup 3]He in a single phase [sup 3]He-[sup 4]He solution. The [sup 3]He in superfluid [sup 4]He acts in a manner of an ideal gas in a vacuum. Thus, refrigeration is obtained using any conventional thermal cycle, but preferably a Stirling or Carnot cycle. A single phase solution of liquid [sup 3]He at an initial concentration in superfluid [sup 4]He is contained in a first variable volume connected to a second variable volume through a superleak device that enables free passage of [sup 4]He while restricting passage of [sup 3]He. The [sup 3]He is compressed (concentrated) and expanded (diluted) in a phased manner to carry out the selected thermal cycle to remove heat from the heat load for cooling below 1 K. 12 figs.

  12. Breaking a vicious cycle.

    PubMed

    Hayes, Daniel F; Allen, Jeff; Compton, Carolyn; Gustavsen, Gary; Leonard, Debra G B; McCormack, Robert; Newcomer, Lee; Pothier, Kristin; Ransohoff, David; Schilsky, Richard L; Sigal, Ellen; Taube, Sheila E; Tunis, Sean R

    2013-07-31

    Despite prodigious advances in tumor biology research, few tumor-biomarker tests have been adopted as standard clinical practice. This lack of reliable tests stems from a vicious cycle of undervaluation, resulting from inconsistent regulatory standards and reimbursement, as well as insufficient investment in research and development, scrutiny of biomarker publications by journals, and evidence of analytical validity and clinical utility. We offer recommendations designed to serve as a roadmap to break this vicious cycle and call for a national dialogue, as changes in regulation, reimbursement, investment, peer review, and guidelines development require the participation of all stakeholders. PMID:23903752

  13. Global water cycle

    NASA Technical Reports Server (NTRS)

    Robertson, Franklin R.; Christy, John R.; Goodman, Steven J.; Miller, Tim L.; Fitzjarrald, Dan; Lapenta, Bill; Wang, Shouping

    1991-01-01

    The primary objective is to determine the scope and interactions of the global water cycle with all components of the Earth system and to understand how it stimulates and regulates changes on both global and regional scales. The following subject areas are covered: (1) water vapor variability; (2) multi-phase water analysis; (3) diabatic heating; (4) MSU (Microwave Sounding Unit) temperature analysis; (5) Optimal precipitation and streamflow analysis; (6) CCM (Community Climate Model) hydrological cycle; (7) CCM1 climate sensitivity to lower boundary forcing; and (8) mesoscale modeling of atmosphere/surface interaction.

  14. Global water cycle

    NASA Technical Reports Server (NTRS)

    Robertson, Franklin; Goodman, Steven J.; Christy, John R.; Fitzjarrald, Daniel E.; Chou, Shi-Hung; Crosson, William; Wang, Shouping; Ramirez, Jorge

    1993-01-01

    This research is the MSFC component of a joint MSFC/Pennsylvania State University Eos Interdisciplinary Investigation on the global water cycle extension across the earth sciences. The primary long-term objective of this investigation is to determine the scope and interactions of the global water cycle with all components of the Earth system and to understand how it stimulates and regulates change on both global and regional scales. Significant accomplishments in the past year are presented and include the following: (1) water vapor variability; (2) multi-phase water analysis; (3) global modeling; and (4) optimal precipitation and stream flow analysis and hydrologic processes.

  15. Cycles in fossil diversity

    SciTech Connect

    Rohde, Robert A.; Muller, Richard A.

    2004-10-20

    It is well-known that the diversity of life appears to fluctuate during the course the Phanerozoic, the eon during which hard shells and skeletons left abundant fossils (0-542 Ma). Using Sepkoski's compendium of the first and last stratigraphic appearances of 36380 marine genera, we report a strong 62 {+-} 3 Myr cycle, which is particularly strong in the shorter-lived genera. The five great extinctions enumerated by Raup and Sepkoski may be an aspect of this cycle. Because of the high statistical significance, we also consider contributing environmental factors and possible causes.

  16. Synthetic battery cycling techniques

    NASA Technical Reports Server (NTRS)

    Leibecki, H. F.; Thaller, L. H.

    1982-01-01

    Synthetic battery cycling makes use of the fast growing capability of computer graphics to illustrate some of the basic characteristics of operation of individual electrodes within an operating electrochemical cell. It can also simulate the operation of an entire string of cells that are used as the energy storage subsystem of a power system. The group of techniques that as a class have been referred to as Synthetic Battery Cycling is developed in part to try to bridge the gap of understanding that exists between single cell characteristics and battery system behavior.

  17. Urea Cycle Disorders.

    PubMed

    Kleppe, Soledad; Mian, Asad; Lee, Brendan

    2003-07-01

    Urea cycle disorders comprise a group of inborn errors of metabolism that represent unique gene-nutrient interactions whose significant morbidity arises from acute and chronic neurotoxicity associated with often massive hyperammonemia. Current paradigms of treatment are focused on controlling the flux of nitrogen transfer through the hepatic urea cycle by a combination of dietary and pharmacologic approaches. Evolving paradigms include the development of cell and gene therapies. Current research is focused on understanding the pathophysiology of ammonia-mediated toxicity and prevention of neural injury. PMID:12791198

  18. Metabolic cycle, cell cycle, and the finishing kick to Start

    PubMed Central

    Futcher, Bruce

    2006-01-01

    Slowly growing budding yeast store carbohydrate, then liquidate it in late G1 phase of the cell cycle, superimposing a metabolic cycle on the cell cycle. This metabolic cycle may separate biochemically incompatible processes. Alternatively it may provide a burst of energy and material for commitment to the cell cycle. Stored carbohydrate could explain the size requirement for cells passing the Start point. PMID:16677426

  19. MERCURY CYCLING AND BIOMAGNIFICATION

    EPA Science Inventory

    Mercury cycling and biomagnification was studied in man-made ponds designed for watering livestock on the Cheyenne River Sioux Reservation in South Dakota. Multiple Hg species were quantified through multiple seasons for 2 years in total atmospheric deposition samples, surface wa...

  20. Assisted Cycling Tours

    ERIC Educational Resources Information Center

    Hollingsworth, Jan Carter

    2008-01-01

    This article discusses Assisted Cycling Tours (ACT), a Westminster, Colorado based 501(c)3, non-profit that is offering the joy of bicycle tours in breathtaking, scenic locations to children and adults with developmental and physical disabilities and their families. ACT was founded by Bob Matter and his son David with a goal of opening up the…

  1. Rapid cycling superconducting magnets

    NASA Astrophysics Data System (ADS)

    Fabbricatore, P.; Farinon, S.; Gambardella, U.; Greco, M.; Volpini, G.

    2006-04-01

    The paper deals with the general problematic related to the development of fast cycled superconducting magnets for application in particle accelerator machines. Starting from the requirements of SIS300 synchrotron under design at GSI and an envisaged future Super-SPS injector at CERN, it is shown which developments are mandatory in the superconducting wire technology and in the magnet design field.

  2. Stirling cycle piston engine

    SciTech Connect

    Morgan, G. R.

    1985-02-12

    This device is an improvement over the conventional type of Stirling cycle engine where the expander piston is connected to a crankshaft and the displacer piston is connected to the same or another crankshaft for operation. The improvement is based on both the expansion and displacer pistons being an integral unit having regenerating means which eliminate the mechanisms that synchronize the regeneration mode.

  3. The Science of Cycling

    ERIC Educational Resources Information Center

    Crompton, Zoe; Daniels, Shelley

    2014-01-01

    Children are engaged by finding out about science in the real world (Harlen, 2010). Many children will be cyclists or will have seen or heard about the success of British cyclists in the Olympics and the Tour de France. This makes cycling a good hook to draw children into learning science. It is also a good cross-curricular topic, with strong…

  4. Re-Cycling

    ERIC Educational Resources Information Center

    Brown, Robert W.; Covault, Corbin E.

    2015-01-01

    An old comedy routine on Saturday Night Live by Father Guido Sarducci introduced a "Five-Minute University," because five minutes is all that's remembered after graduation anyway. In counterpoint, we discuss "cycling," a teaching method for memory enhancement. Our principal implementation consists of offering a simple version…

  5. LIFE-CYCLE ASSESSMENT

    EPA Science Inventory

    Life Cycle Assessment, or LCA, is an environmental accounting and mangement approach that consider all the aspects of resource use and environmental releases associated with an industrial system from cradle-to-grave. Specifically, it is a holistic view of environmental interacti...

  6. 90-Day Cycle Handbook

    ERIC Educational Resources Information Center

    Park, Sandra; Takahashi, Sola

    2013-01-01

    90-Day Cycles are a disciplined and structured form of inquiry designed to produce and test knowledge syntheses, prototyped processes, or products in support of improvement work. With any type of activity, organizations inevitably encounter roadblocks to improving performance and outcomes. These barriers might include intractable problems at…

  7. The Geologic Nitrogen Cycle

    NASA Astrophysics Data System (ADS)

    Johnson, B. W.; Goldblatt, C.

    2013-12-01

    N2 is the dominant gas in Earth's atmosphere, and has been so through the majority of the planet's history. Originally thought to only be cycled in significant amounts through the biosphere, it is becoming increasingly clear that a large degree of geologic cycling can occur as well. N is present in crustal rocks at 10s to 100s of ppm and in the mantle at 1s to perhaps 10s of ppm. In light of new data, we present an Earth-system perspective of the modern N cycle, an updated N budget for the silicate Earth, and venture to explain the evolution of the N cycle over time. In an fashion similar to C, N has a fast, biologically mediated cycle and a slower cycle driven by plate tectonics. Bacteria fix N2 from the atmosphere into bioavailable forms. N is then cycled through the food chain, either by direct consumption of N-fixing bacteria, as NH4+ (the primary waste form), or NO3- (the most common inorganic species in the modern ocean). Some organic material settles as sediment on the ocean floor. In anoxic sediments, NH4+ dominates; due to similar ionic radii, it can readily substitute for K+ in mineral lattices, both in sedimentary rocks and in oceanic lithosphere. Once it enters a subduction zone, N may either be volatilized and returned to the atmosphere at arc volcanoes as N2 or N2O, sequestered into intrusive igneous rocks (as NH4+?), or subducted deep into the mantle, likely as NH4+. Mounting evidence indicates that a significant amount of N may be sequestered into the solid Earth, where it may remain for long periods (100s m.y.) before being returned to the atmosphere/biosphere by volcanism or weathering. The magnitude fluxes into the solid Earth and size of geologic N reservoirs are poorly constrained. The size of the N reservoirs contained in the solid Earth directly affects the evolution of Earth's atmosphere. It is possible that N now sequestered in the solid Earth was once in the atmosphere, which would have resulted in a higher atmospheric pressure, and

  8. The Synthesis and Characterization of Aromatic Hybrid Anderson-Evans POMs and their Serum Albumin Interactions: The Shift from Polar to Hydrophobic Interactions.

    PubMed

    Al-Sayed, Emir; Blazevic, Amir; Roller, Alexander; Rompel, Annette

    2015-12-01

    Four aromatic hybrid Anderson polyoxomolybdates with Fe(3+) or Mn(3+) as the central heteroatom have been synthesized by using a pre-functionalization protocol and characterized by using single-crystal X-ray diffraction, FTIR, ESI-MS, (1) H NMR spectroscopy, and elemental analysis. Structural analysis revealed the formation of (TBA)3 [FeMo6 O18 {(OCH2 )3 CNHCOC6 H5 }2 ]⋅3.5 ACN (TBA-FeMo6 -bzn; TBA=tetrabutylammonium, ACN=acetonitrile, bzn=TRIS-benzoic acid alkanolamide, TRISR=(HOCH2 )3 CR)), (TBA)3 [FeMo6 O18 {(OCH2 )3 CNHCOC8 H7 }2 ]⋅2.5 ACN (TBA-FeMo6 -cin; cin=TRIS-cinnamic acid alkanolamide), (TBA)3 [MnMo6 O18 {(OCH2 )3 CNHCOC6 H5 }2 ]⋅3.5 ACN (TBA-MnMo6 -bzn), and (TBA)3 [MnMo6 O18 {(OCH2 )3 CNHCOC8 H7 }2 ]⋅2.5 ACN (TBA-MnMo6 -cin). To make these four compounds applicable in biological systems, an ion exchange was performed that gave the water-soluble (up to 80 mM) sodium salts Na3 [FeMo6 O18 {(OCH2 )3 CNHCOC6 H5 }2 ] (Na-FeMo6 -bzn), Na3 [FeMo6 O18 {(OCH2 )3 CNHCOC8 H7 }2 ] (Na-FeMo6 -cin), Na3 [MnMo6 O18 {(OCH2 )3 CNHCOC6 H5 }2 ] (Na-MnMo6 -bzn), and Na3 [MnMo6 O18 {(OCH2 )3 CNHCOC8 H7 }2 ] (Na-MnMo6 -cin). The hydrolytic stability of the sodium salts was examined by applying ESI-MS in the pH range of 4 to 9. Sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) showed that human and bovine serum albumin (HSA and BSA) remain intact in solutions that contain up to 100 equivalents of the sodium salts over more than 4 d at 20 °C. Tryptophan (Trp) fluorescence quenching was applied to study the interactions between the sodium salts and HSA and BSA at pH 5.5 and 7.4. The quenching constants were extracted by using Stern-Volmer analysis, which suggested the formation of a 1:1 POM-protein complex in all samples. It is suggested that the aromatic hybrid POM approaches subdomain IIA of HSA and exhibits hydrophobic interactions with its hydrophobic tails, whereas the Anderson core is stabilized through electrostatic

  9. The M. D. Anderson Symptom Inventory-Head and Neck Module, a Patient-Reported Outcome Instrument, Accurately Predicts the Severity of Radiation-Induced Mucositis

    SciTech Connect

    Rosenthal, David I. Mendoza, Tito R.; Chambers, Mark; Burkett, V. Shannon; Garden, Adam S.; Hessell, Amy C.; Lewin, Jan S.; Ang, K. Kian; Kies, Merrill S.

    2008-12-01

    Purpose: To compare the M. D. Anderson Symptom Inventory-Head and Neck (MDASI-HN) module, a symptom burden instrument, with the Functional Assessment of Cancer Therapy-Head and Neck (FACT-HN) module, a quality-of-life instrument, for the assessment of mucositis in patients with head-and-neck cancer treated with radiotherapy and to identify the most distressing symptoms from the patient's perspective. Methods and Materials: Consecutive patients with head-and-neck cancer (n = 134) completed the MDASI-HN and FACT-HN before radiotherapy (time 1) and after 6 weeks of radiotherapy or chemoradiotherapy (time 2). The mean global and subscale scores for each instrument were compared with the objective mucositis scores determined from the National Cancer Institute Common Terminology Criteria for Adverse Events, version 3.0. Results: The global and subscale scores for each instrument showed highly significant changes from time 1 to time 2 and a significant correlation with the objective mucositis scores at time 2. Only the MDASI scores, however, were significant predictors of objective Common Terminology Criteria for Adverse Events mucositis scores on multivariate regression analysis (standardized regression coefficient, 0.355 for the global score and 0.310 for the head-and-neck cancer-specific score). Most of the moderate and severe symptoms associated with mucositis as identified on the MDASI-HN are not present on the FACT-HN. Conclusion: Both the MDASI-HN and FACT-HN modules can predict the mucositis scores. However, the MDASI-HN, a symptom burden instrument, was more closely associated with the severity of radiation-induced mucositis than the FACT-HN on multivariate regression analysis. This greater association was most likely related to the inclusion of a greater number of face-valid mucositis-related items in the MDASI-HN compared with the FACT-HN.

  10. Long-term outcome of patients with spinal myxopapillary ependymoma: treatment results from the MD Anderson Cancer Center and institutions from the Rare Cancer Network

    PubMed Central

    Weber, Damien C.; Wang, Yucai; Miller, Robert; Villà, Salvador; Zaucha, Renata; Pica, Alessia; Poortmans, Philip; Anacak, Yavuz; Ozygit, Gokhan; Baumert, Birgitta; Haller, Guy; Preusser, Matthias; Li, Jing

    2015-01-01

    Background Spinal myxopapillary ependymomas (MPEs) are slowly growing ependymal gliomas with preferential manifestation in young adults. The aim of this study was to assess the outcome of patients with MPE treated with surgery, radiotherapy (RT), and/or chemotherapy. Methods The medical records of 183 MPE patients (male: 59%) treated at the MD Anderson Cancer Center and 11 institutions from the Rare Cancer Network were retrospectively reviewed. Mean patient' age at diagnosis was 35.5 ± 15.8 years. Ninety-seven (53.0%) patients underwent surgery without RT, and 86 (47.0%) were treated with surgery and/or RT. Median RT dose was 50.4 Gy. Median follow-up was 83.9 months. Results Fifteen (8.2%) patients died, 7 of unrelated cause. The estimated 10-year overall survival was 92.4% (95% CI: 87.7–97.1). Treatment failure was observed in 58 (31.7%) patients. Local failure, distant spinal relapse, and brain failure were observed in 49 (26.8%), 17 (9.3%), and 11 (6.0%) patients, respectively. The estimated 10-year progression-free survival was 61.2% (95% CI: 52.8–69.6). Age (<36 vs ≥36 y), treatment modality (surgery alone vs surgery and RT), and extent of surgery were prognostic factors for local control and progression-free survival on univariate and multivariate analysis. Conclusions In this series, treatment failure of MPE occurred in approximately one third of patients. The observed recurrence pattern of primary spinal MPE was mainly local, but a substantial number of patients failed nonlocally. Younger patients and those not treated initially with adjuvant RT or not undergoing gross total resection were significantly more likely to present with tumor recurrence/progression. PMID:25301811

  11. Examining the role of foraging and malvolio in host-finding behavior in the honey bee parasite, Varroa destructor (Anderson & Trueman).

    PubMed

    Cabrera, Ana R; Shirk, Paul D; Teal, Peter E A; Grozinger, Christina M; Evans, Jay D

    2014-02-01

    When a female varroa mite, Varroa destructor (Anderson & Trueman), invades a honey bee brood cell, the physiology rapidly changes from feeding phoretic to reproductive. Changes in foraging and malvolio transcript levels in the brain have been associated with modulated intra-specific food searching behaviors in insects and other invertebrates. Transcription profiles for both genes were examined during and immediately following brood cell invasion to assess their role as potential control elements. Vdfor and Vdmvl transcripts were found in all organs of varroa mites with the highest Vdfor transcript levels in ovary-lyrate organs and the highest Vdmvl in Malpighian tubules. Changes in transcript levels of Vdfor and Vdmvl in synganglia were not associated with the cell invasion process, remaining comparable between early reproductive mites (collected from the pre-capping brood cells) and phoretic mites. However, Vdfor and Vdmvl transcript levels were lowered by 37 and 53%, respectively, in synganglia from reproductive mites compared to early reproductive mites, but not significantly different to levels in synganglia from phoretic mites. On the other hand, in whole body preparations the Vdfor and Vdmvl had significantly higher levels of transcript in reproductive mites compared to phoretic and early reproductive, mainly due to the presence of both transcripts accumulating in the eggs carried by the ovipositing mite. Varroa mites are a critical component for honey bee population decline and finding varroa mite genes associated with brood cell invasion, reproduction, ion balance and other physiological processes will facilitate development of novel control avenues for this honey bee parasite. PMID:24375502

  12. Stirling cycle cryogenic cooler

    NASA Astrophysics Data System (ADS)

    Gasser, M. G.; Sherman, A.; Studer, P. A.; Daniels, A.; Goldowsky, M. P.

    1983-06-01

    A long lifetime Stirling cycle cryogenic cooler particularly adapted for space applications is described. It consists of a compressor section centrally aligned end to end with an expansion section, and respectively includes a reciprocating compressor piston and displacer radially suspended in interconnecting cylindrical housings by active magnetic bearings and has adjacent reduced clearance regions so as to be in noncontacting relationship therewith and wherein one or more of these regions operate as clearance seals. The piston and displacer are reciprocated in their housings by linear drive motors to vary the volume of respectively adjacent compression and expansion spaces which contain a gaseous working fluid and a thermal regenerator to effect Stirling cycle cryogenic cooling.

  13. Stirling cycle cryogenic cooler

    NASA Technical Reports Server (NTRS)

    Gasser, M. G.; Sherman, A.; Studer, P. A.; Daniels, A.; Goldowsky, M. P. (Inventor)

    1983-01-01

    A long lifetime Stirling cycle cryogenic cooler particularly adapted for space applications is described. It consists of a compressor section centrally aligned end to end with an expansion section, and respectively includes a reciprocating compressor piston and displacer radially suspended in interconnecting cylindrical housings by active magnetic bearings and has adjacent reduced clearance regions so as to be in noncontacting relationship therewith and wherein one or more of these regions operate as clearance seals. The piston and displacer are reciprocated in their housings by linear drive motors to vary the volume of respectively adjacent compression and expansion spaces which contain a gaseous working fluid and a thermal regenerator to effect Stirling cycle cryogenic cooling.

  14. The carbon dioxide cycle

    USGS Publications Warehouse

    James, P.B.; Hansen, G.B.; Titus, T.N.

    2005-01-01

    The seasonal CO2 cycle on Mars refers to the exchange of carbon dioxide between dry ice in the seasonal polar caps and gaseous carbon dioxide in the atmosphere. This review focuses on breakthroughs in understanding the process involving seasonal carbon dioxide phase changes that have occurred as a result of observations by Mars Global Surveyor. ?? 2004 COSPAR. Published by Elsevier Ltd. All rights reserved.

  15. Stirling cycle engine

    DOEpatents

    Lundholm, Gunnar

    1983-01-01

    In a Stirling cycle engine having a plurality of working gas charges separated by pistons reciprocating in cylinders, the total gas content is minimized and the mean pressure equalization among the serial cylinders is improved by using two piston rings axially spaced at least as much as the piston stroke and by providing a duct in the cylinder wall opening in the space between the two piston rings and leading to a source of minimum or maximum working gas pressure.

  16. Nuclear Fuel Cycle

    SciTech Connect

    Dale, Deborah J.

    2014-10-28

    These slides will be presented at the training course “International Training Course on Implementing State Systems of Accounting for and Control (SSAC) of Nuclear Material for States with Small Quantity Protocols (SQP),” on November 3-7, 2014 in Santa Fe, New Mexico. The slides provide a basic overview of the Nuclear Fuel Cycle. This is a joint training course provided by NNSA and IAEA.

  17. The urea cycle disorders.

    PubMed

    Helman, Guy; Pacheco-Colón, Ileana; Gropman, Andrea L

    2014-07-01

    The urea cycle is the primary nitrogen-disposal pathway in humans. It requires the coordinated function of six enzymes and two mitochondrial transporters to catalyze the conversion of a molecule of ammonia, the α-nitrogen of aspartate, and bicarbonate into urea. Whereas ammonia is toxic, urea is relatively inert, soluble in water, and readily excreted by the kidney in the urine. Accumulation of ammonia and other toxic intermediates of the cycle lead to predominantly neurologic sequelae. The disorders may present at any age from the neonatal period to adulthood, with the more severely affected patients presenting earlier in life. Patients are at risk for metabolic decompensation throughout life, often triggered by illness, fasting, surgery and postoperative states, peripartum, stress, and increased exogenous protein load. Here the authors address neurologic presentations of ornithine transcarbamylase deficiency in detail, the most common of the urea cycle disorders, neuropathology, neurophysiology, and our studies in neuroimaging. Special attention to late-onset presentations is given. PMID:25192511

  18. Gap Cycling for SWIFT

    PubMed Central

    Corum, Curtis A.; Idiyatullin, Djaudat; Snyder, Carl J.; Garwood, Michael

    2014-01-01

    Purpose SWIFT (SWeep Imaging with Fourier Transformation) is a non-Cartesian MRI method with unique features and capabilities. In SWIFT, radiofrequency (RF) excitation and reception are performed nearly simultaneously, by rapidly switching between transmit and receive during a frequency-swept RF pulse. Because both the transmitted pulse and data acquisition are simultaneously amplitude-modulated in SWIFT (in contrast to continuous RF excitation and uninterrupted data acquisition in more familiar MRI sequences), crosstalk between different frequency bands occurs in the data. This crosstalk leads to a “bulls-eye” artifact in SWIFT images. We present a method to cancel this inter-band crosstalk by cycling the pulse and receive gap positions relative to the un-gapped pulse shape. We call this strategy “gap cycling.” Methods We carry out theoretical analysis, simulation and experiments to characterize the signal chain, resulting artifacts, and their elimination for SWIFT. Results Theoretical analysis reveals the mechanism for gap-cycling’s effectiveness in canceling inter-band crosstalk in the received data. We show phantom and in-vivo results demonstrating bulls-eye artifact free images. Conclusion Gap cycling is an effective method to remove bulls-eye artifact resulting from inter-band crosstalk in SWIFT data. PMID:24604286

  19. Episodic Tremor and Slip: Cycles Within Cycles

    NASA Astrophysics Data System (ADS)

    Creager, K. C.; Wech, A.; Vidale, J. E.

    2009-12-01

    Episodic tremor and slip (ETS) events, each with geodetically determined moment magnitudes in the mid-6 range, repeat about every 15 months under the Olympic Peninsula/southern Vancouver Island region. We have automatically searched for non-volcanic tremor in all 5-minute time windows both during the past five ETS events and during the two inter-ETS periods from February, 2007 through April, 2008 and June 2008 through April 2009. Inter-ETS tremor was detected in 5000 windows, which overlap by 50%, so tremor was seen 2% of the time. The catalog of 5-minute tremor locations cluster in time and space into groups we call tremor swarms, revealing 50 inter-ETS tremor swarms. The number of hours of tremor per swarm ranged from about 1 to 68, totaling 374 hours. The inter-ETS tremor swarms generally locate along the downdip side of the major ETS events, and account for approximately 45% of the time that tremor has been detected during the last two entire ETS cycles. Many of the inter-ETS events are near-carbon copies in duration, spatial extent and propagation direction, as is seen for the larger 15-month-interval events. These 50 inter-ETS swarms plus two major ETS episodes follow a power law relationship such that the number of swarms, N, exceeding duration τ is given by N ˜ τ-0.7. If we assume that seismic moment is proportional to τ as proposed by Ide et al. [Nature, 2007], we find that the tremor swarms follow a standard Gutenberg-Richter logarithmic frequency-magnitude relation, N ˜ 10-bMw, with b = 1.0, which lies in the range for normal earthquake catalogs. Furthermore, the major ETS events fall on the curve defined by the inter-ETS swarms, suggesting that the inter-ETS swarms are just smaller versions of the major 15-month ETS events. Only the largest events coincide with geodetically observed slip, suggesting that current geodetic observations may be missing nearly half of the total slip. Finally, crude estimates of the spatial dimensions of tremor swarms L

  20. The Contemporary Carbon Cycle

    NASA Astrophysics Data System (ADS)

    Houghton, R. A.

    2003-12-01

    The global carbon cycle refers to the exchanges of carbon within and between four major reservoirs: the atmosphere, the oceans, land, and fossil fuels. Carbon may be transferred from one reservoir to another in seconds (e.g., the fixation of atmospheric CO2 into sugar through photosynthesis) or over millennia (e.g., the accumulation of fossil carbon (coal, oil, gas) through deposition and diagenesis of organic matter). This chapter emphasizes the exchanges that are important over years to decades and includes those occurring over the scale of months to a few centuries. The focus will be on the years 1980-2000 but our considerations will broadly include the years ˜1850-2100. Chapter 8.09, deals with longer-term processes that involve rates of carbon exchange that are small on an annual timescale (weathering, vulcanism, sedimentation, and diagenesis).The carbon cycle is important for at least three reasons. First, carbon forms the structure of all life on the planet, making up ˜50% of the dry weight of living things. Second, the cycling of carbon approximates the flows of energy around the Earth, the metabolism of natural, human, and industrial systems. Plants transform radiant energy into chemical energy in the form of sugars, starches, and other forms of organic matter; this energy, whether in living organisms or dead organic matter, supports food chains in natural ecosystems as well as human ecosystems, not the least of which are industrial societies habituated (addicted?) to fossil forms of energy for heating, transportation, and generation of electricity. The increased use of fossil fuels has led to a third reason for interest in the carbon cycle. Carbon, in the form of carbon dioxide (CO2) and methane (CH4), forms two of the most important greenhouse gases. These gases contribute to a natural greenhouse effect that has kept the planet warm enough to evolve and support life (without the greenhouse effect the Earth's average temperature would be -33

  1. Rapid Cycling and Its Treatment

    MedlinePlus

    ... may be rapid, ultra-rapid or ultradian cycling. Biological rhythm disturbances: This theory proposes that people with rapid cycling have daily biological rhythms that are out of sync with typical “ ...

  2. Fictitious Supercontinent Cycles

    NASA Astrophysics Data System (ADS)

    Marvin Herndon, J.

    2014-05-01

    "Supercontinent cycles" or "Wilson cycles" is the idea that before Pangaea there were a series of supercontinents that each formed and then broke apart and separated before colliding again, re-aggregating, and suturing into a new supercontinent in a continuing sequence. I suggest that "supercontinent cycles" are artificial constructs, like planetary orbit epicycles, attempts to describe geological phenomena within the framework of problematic paradigms, namely, planetesimal Earth formation and plate tectonics' mantle convection. The so-called 'standard model of solar system formation' is problematic as it would lead to insufficiently massive planetary cores and necessitates additional ad hoc hypotheses such as the 'frost line' between Mars and Jupiter to explain planetary differences and whole-planet melting to explain core formation from essentially undifferentiated matter. The assumption of mantle convection is crucial for plate tectonics, not only for seafloor spreading, but also for continental movement; continent masses are assumed to ride atop convection cells. In plate tectonics, plate collisions are thought to be the sole mechanism for fold-mountain formation. Indeed, the occurrence of mountain chains characterized by folding which significantly predate the breakup of Pangaea is the primary basis for assuming the existence of supercontinent cycles with their respective periods of ancient mountain-forming plate collisions. Mantle convection is physically impossible. Rayleigh Number justification has been misapplied. The mantle bottom is too dense to float to the surface by thermal expansion. Sometimes attempts are made to obviate the 'bottom heavy' prohibition by adopting the tacit assumption that the mantle behaves as an ideal gas with no viscous losses, i.e., 'adiabatic'. But the mantle is a solid that does not behave as an ideal gas as evidenced by earthquakes occurring at depths as great as 660 km. Absent mantle convection, plate tectonics is not valid

  3. GEOSS Water Cycle Integrator

    NASA Astrophysics Data System (ADS)

    Koike, T.; Lawford, R. G.; Cripe, D.

    2012-12-01

    It is critically important to recognize and co-manage the fundamental linkages across the water-dependent domains; land use, including deforestation; ecosystem services; and food-, energy- and health-securities. Sharing coordinated, comprehensive and sustained observations and information for sound decision-making is a first step; however, to take full advantage of these opportunities, we need to develop an effective collaboration mechanism for working together across different disciplines, sectors and agencies, and thereby gain a holistic view of the continuity between environmentally sustainable development, climate change adaptation and enhanced resilience. To promote effective multi-sectoral, interdisciplinary collaboration based on coordinated and integrated efforts, the Global Earth Observation System of Systems (GEOSS) is now developing a "GEOSS Water Cycle Integrator (WCI)", which integrates "Earth observations", "modeling", "data and information", "management systems" and "education systems". GEOSS/WCI sets up "work benches" by which partners can share data, information and applications in an interoperable way, exchange knowledge and experiences, deepen mutual understanding and work together effectively to ultimately respond to issues of both mitigation and adaptation. (A work bench is a virtual geographical or phenomenological space where experts and managers collaborate to use information to address a problem within that space). GEOSS/WCI enhances the coordination of efforts to strengthen individual, institutional and infrastructure capacities, especially for effective interdisciplinary coordination and integration. GEO has established the GEOSS Asian Water Cycle Initiative (AWCI) and GEOSS African Water Cycle Coordination Initiative (AfWCCI). Through regional, inter-disciplinary, multi-sectoral integration and inter-agency coordination in Asia and Africa, GEOSS/WCI is now leading to effective actions and public awareness in support of water security and

  4. GEOSS Water Cycle Integrator

    NASA Astrophysics Data System (ADS)

    Koike, Toshio; Lawford, Richard; Cripe, Douglas

    2013-04-01

    It is critically important to recognize and co-manage the fundamental linkages across the water-dependent domains; land use, including deforestation; ecosystem services; and food-, energy- and health-securities. Sharing coordinated, comprehensive and sustained observations and information for sound decision-making is a first step; however, to take full advantage of these opportunities, we need to develop an effective collaboration mechanism for working together across different disciplines, sectors and agencies, and thereby gain a holistic view of the continuity between environmentally sustainable development, climate change adaptation and enhanced resilience. To promote effective multi-sectoral, interdisciplinary collaboration based on coordinated and integrated efforts, the intergovernmental Group on Earth Observations (GEO) is implementing the Global Earth Observation System of Systems (GEOSS). A component of GEOSS now under development is the "GEOSS Water Cycle Integrator (WCI)", which integrates Earth observations, modeling, data and information, management systems and education systems. GEOSS/WCI sets up "work benches" by which partners can share data, information and applications in an interoperable way, exchange knowledge and experiences, deepen mutual understanding and work together effectively to ultimately respond to issues of both mitigation and adaptation. (A work bench is a virtual geographical or phenomenological space where experts and managers collaborate to use information to address a problem within that space). GEOSS/WCI enhances the coordination of efforts to strengthen individual, institutional and infrastructure capacities, especially for effective interdisciplinary coordination and integration. GEO has established the GEOSS Asian Water Cycle Initiative (AWCI) and GEOSS African Water Cycle Coordination Initiative (AfWCCI). Through regional, inter-disciplinary, multi-sectoral integration and inter-agency coordination in Asia and Africa, GEOSS

  5. On the Importance of Cycle Minimum in Sunspot Cycle Prediction

    NASA Technical Reports Server (NTRS)

    Wilson, Robert M.; Hathaway, David H.; Reichmann, Edwin J.

    1996-01-01

    The characteristics of the minima between sunspot cycles are found to provide important information for predicting the amplitude and timing of the following cycle. For example, the time of the occurrence of sunspot minimum sets the length of the previous cycle, which is correlated by the amplitude-period effect to the amplitude of the next cycle, with cycles of shorter (longer) than average length usually being followed by cycles of larger (smaller) than average size (true for 16 of 21 sunspot cycles). Likewise, the size of the minimum at cycle onset is correlated with the size of the cycle's maximum amplitude, with cycles of larger (smaller) than average size minima usually being associated with larger (smaller) than average size maxima (true for 16 of 22 sunspot cycles). Also, it was found that the size of the previous cycle's minimum and maximum relates to the size of the following cycle's minimum and maximum with an even-odd cycle number dependency. The latter effect suggests that cycle 23 will have a minimum and maximum amplitude probably larger than average in size (in particular, minimum smoothed sunspot number Rm = 12.3 +/- 7.5 and maximum smoothed sunspot number RM = 198.8 +/- 36.5, at the 95-percent level of confidence), further suggesting (by the Waldmeier effect) that it will have a faster than average rise to maximum (fast-rising cycles have ascent durations of about 41 +/- 7 months). Thus, if, as expected, onset for cycle 23 will be December 1996 +/- 3 months, based on smoothed sunspot number, then the length of cycle 22 will be about 123 +/- 3 months, inferring that it is a short-period cycle and that cycle 23 maximum amplitude probably will be larger than average in size (from the amplitude-period effect), having an RM of about 133 +/- 39 (based on the usual +/- 30 percent spread that has been seen between observed and predicted values), with maximum amplitude occurrence likely sometime between July 1999 and October 2000.

  6. Geomicrobiological cycling of antimony

    NASA Astrophysics Data System (ADS)

    Kulp, T. R.; Terry, L.; Dovick, M. A.; Braiotta, F.

    2013-12-01

    Microbiologically catalyzed oxidation and reduction of toxic metalloids (e.g., As, Se, and Te) generally proceeds much faster than corresponding abiotic reactions. These microbial transformations constitute biogeochemical cycles that control chemical speciation and environmental behavior of metalloids in aqueous environments. Particular progress has been made over the past two decades in documenting microbiological biotransformations of As, which include anaerobic respiratory reduction of As(V) to As(III), oxidation of As(III) to As(V) linked to chemoautotrophy or photoautotrophy, and cellular detoxification pathways. By contrast, microbial interactions with Sb, As's group 15 neighbor and a toxic element of emerging global concern, are poorly understood. Our work with sediment microcosms, enrichment cultures, and bacterial isolates suggests that prokaryotic metabolisms may be similarly important to environmental Sb cycling. Enrichment cultures and isolates from a Sb-contaminated mine site in Idaho exhibited Sb(V)-dependent heterotrophic respiration under anaerobic conditions and Sb(III)-dependent autotrophic growth in the presence of air. Live, anoxic cultures reduced 2 mM Sb(V) to Sb(III) within 5 d, while no activity occurred in killed controls. Sb(V) reduction was stimulated by lactate or acetate and was quantitatively coupled to the oxidation of lactate. The oxidation of radiolabeled 14C-acetate (monitored by GC-GPC) demonstrated Sb(V)-dependent oxidation to 14CO2, suggesting a dissimilatory process. Sb(V) dependent growth in cultures was demonstrated by direct counting. Microbiological reduction of Sb(V) also occurred in anerobic sediment microcosms from an uncontaminated suburban lake, but did not appear to be linked to growth and is interpreted as a mechanism of biological detoxification. Aerobic microcosms and cultures from the Idaho mine oxidized 2 mM Sb(III) to Sb(V) within 7 d and coupled this reaction to cell growth quantified by direct counting. An

  7. Natural Cycles, Gases

    NASA Technical Reports Server (NTRS)

    Douglass, Anne R.; Jackman, Charles H.; Rood, R. B.; Aikin, A. C.; Stolarski, R. S.; Mccormick, M. P.; Fahey, David W.

    1992-01-01

    The major gaseous components of the exhaust of stratospheric aircraft are expected to be the products of combustion (CO2 and H2O), odd nitrogen (NO, NO2 HNO3), and products indicating combustion inefficiencies (CO and total unburned hydrocarbons). The species distributions are produced by a balance of photochemical and transport processes. A necessary element in evaluating the impact of aircraft exhaust on the lower stratospheric composition is to place the aircraft emissions in perspective within the natural cycles of stratospheric species. Following are a description of mass transport in the lower stratosphere and a discussion of the natural behavior of the major gaseous components of the stratospheric aircraft exhaust.

  8. Liquid air cycle engines

    NASA Technical Reports Server (NTRS)

    Rosevear, Jerry

    1992-01-01

    Given here is a definition of Liquid Air Cycle Engines (LACE) and existing relevant technologies. Heat exchanger design and fabrication techniques, the handling of liquid hydrogen to achieve the greatest heat sink capabilities, and air decontamination to prevent heat exchanger fouling are discussed. It was concluded that technology needs to be extended in the areas of design and fabrication of heat exchangers to improve reliability along with weight and volume reductions. Catalysts need to be improved so that conversion can be achieved with lower quantities and lower volumes. Packaging studies need to be investigated both analytically and experimentally. Recycling with slush hydrogen needs further evaluation with experimental testing.

  9. Geothermal Life Cycle Calculator

    DOE Data Explorer

    Sullivan, John

    2014-03-11

    This calculator is a handy tool for interested parties to estimate two key life cycle metrics, fossil energy consumption (Etot) and greenhouse gas emission (ghgtot) ratios, for geothermal electric power production. It is based solely on data developed by Argonne National Laboratory for DOE’s Geothermal Technologies office. The calculator permits the user to explore the impact of a range of key geothermal power production parameters, including plant capacity, lifetime, capacity factor, geothermal technology, well numbers and depths, field exploration, and others on the two metrics just mentioned. Estimates of variations in the results are also available to the user.

  10. Cycling Joule Thomson refrigerator

    NASA Technical Reports Server (NTRS)

    Tward, E. (Inventor)

    1983-01-01

    A symmetrical adsorption pump/compressor system having a pair of mirror image legs and a Joule Thomson expander, or valve, interposed between the legs thereof for providing a, efficient refrigeration cycle is described. The system further includes a plurality of gas operational heat switches adapted selectively to transfer heat from a thermal load and to transfer or discharge heat through a heat projector, such as a radiator or the like. The heat switches comprise heat pressurizable chambers adapted for alternate pressurization in response to adsorption and desorption of a pressurizing gas confined therein.

  11. Stirling cycle machine

    SciTech Connect

    Burnett, S.C.; Purcell, J.R.; Creedon, W.P.; Joshi, C.H.

    1990-06-05

    This patent describes an improvement in a Stirling cycle machine including first and second variable-volume, compression-expansion chambers containing a gas a regenerator interconnecting the chambers and for conducting the gas therebetween, and eccentric drive means for driving the first and second chambers. It comprises: the eccentric drive means comprising a pair of rotatably mounted shafts, at least one pair of eccentric disks fixed on the shafts in phase with each other, and means for causing the shafts and thereby the eccentric disks to rotate in opposite directions.

  12. Re-Cycling

    NASA Astrophysics Data System (ADS)

    Brown, Robert W.; Covault, Corbin E.

    2015-11-01

    An old comedy routine on Saturday Night Live by Father Guido Sarducci introduced a "Five-Minute University," because five minutes is all that's remembered after graduation anyway. In counterpoint, we discuss "cycling," a teaching method for memory enhancement. Our principal implementation consists of offering a simple version of a given course in the first third of the semester, a deeper and more integrated version in the second third, and the final, targeted version in the last third. We describe the benefits and challenges in this tale from the trenches.

  13. Developing a Safe Cycling Course.

    ERIC Educational Resources Information Center

    Riddle, Amy Backus

    1983-01-01

    A cycling course can take advantage of students' interests, teach safe cycling, and give students a fuller appreciation of a lifetime sport. Suggestions for planning and scheduling a cycling course, covering safety procedures, and considering other elements necessary for a successful course are given. (PP)

  14. Sometimes "Newton's Method" Always "Cycles"

    ERIC Educational Resources Information Center

    Latulippe, Joe; Switkes, Jennifer

    2012-01-01

    Are there functions for which Newton's method cycles for all non-trivial initial guesses? We construct and solve a differential equation whose solution is a real-valued function that two-cycles under Newton iteration. Higher-order cycles of Newton's method iterates are explored in the complex plane using complex powers of "x." We find a class of…

  15. Culture in cycles: considering H.T. Odum's 'information cycle'

    NASA Astrophysics Data System (ADS)

    Abel, Thomas

    2014-01-01

    'Culture' remains a conundrum in anthropology. When recast in the mold of 'information cycles,' culture is transformed. New fault lines appear. Information is splintered into parallel or nested forms. Dynamics becomes cycling. Energy is essential. And culture has function in a directional universe. The 'information cycle' is the crowning component of H.T. Odum's theory of general systems. What follows is an application of the information cycle to the cultural domains of discourse, social media, ritual, education, journalism, technology, academia, and law, which were never attempted by Odum. In information cycles, cultural information is perpetuated - maintained against Second Law depreciation. Conclusions are that culture is in fact a nested hierarchy of cultural forms. Each scale of information production is semi-autonomous, with its own evolutionary dynamics of production and selection in an information cycle. Simultaneously, each information cycle is channeled or entrained by its larger scale of information and ultimately human-ecosystem structuring.

  16. Characterizing marine particles and their impact on biogeochemical cycles in the GEOTRACES program

    NASA Astrophysics Data System (ADS)

    Anderson, Robert F.; Hayes, Christopher T.

    2015-04-01

    Trace elements and their isotopes (TEIs) are of priority interest in several subdisciplines of oceanography. For example, the vital role of trace element micronutrients in regulating the growth of marine organisms, which, in turn, may influence the structure and composition of marine ecosystems, is now well established (Morel and Price, 2003; Twining and Baines, 2013). Natural distributions of some TEIs have been severely impacted by anthropogenic emissions, leading to substantial perturbations of natural ocean inventories. Pb and Hg, for example, (Lamborg et al., 2002; Schaule and Patterson, 1981), may represent a significant threat to human food supply. Furthermore, much of our knowledge of past variability in the ocean environment, including the ocean's role in climate change, has been developed using TEI proxies archived in marine substrates such as sediments, corals and microfossils. Research in each of these areas relies on a comprehensive knowledge of the distributions of TEIs in the ocean, and on the sensitivity of these distributions to changing environmental conditions. With numerous processes affecting the regional supply and removal of TEIs in the ocean, a comprehensive understanding of the marine biogeochemical cycles of TEIs can be attained only by a global, coordinated, international effort. GEOTRACES, an international program designed to study the marine biogeochemical cycles of trace elements and their isotopes (Anderson et al., 2014; Henderson et al., 2007), aims to achieve these goals.

  17. Calappid and leucosiid crabs (Crustacea: Decapoda: Brachyura) from Kerala, India, with the description of a new species of Mursia Desmarest, 1823, from the Arabian Sea and redescription of M. bicristimana Alcock & Anderson, 1894.

    PubMed

    Kumar, Biju A; Kumar, M Sushil; Galil, Bella S

    2013-01-01

    Eleven species of calappid and leucosiid crabs were identified from by-catch landed by trawlers at four fishing ports in Kerala, India that were surveyed in 2007 and supplemented by material obtained in January 2013. Four species are reported for the first time from India, six are new records for Kerala. The status of Mursia bicristimana Alcock & Anderson, 1894, is clarified and the species redescribed. A new species of Mursia is described from the Gulf of Aden, Arabian Sea.  PMID:25113495

  18. Air blown gasification cycle

    SciTech Connect

    Dawes, S.G.; Mordecai, M.; Brown, D.; Burnard, G.K.

    1995-12-31

    The Air Blown Gasification Cycle (ABGC) is a hybrid partial gasification cycle based on a novel, air blown pressurized fluidized bed gasifier (PFBG) with a circulating fluidized bed combustor (CFBC) to burn the residual char from the PFBG. The ABGC has been developed primarily as a clean coal generation system and embodies a sulfur capture mechanism based on the addition of limestone, or other sorbent, to the PFBG where it is sulfided in the reducing atmosphere, followed by oxidation to a stable sulfate residue in the CFBC. In order to achieve commercialization, certain key technological issues needed to be addressed and an industry-led consortium was established to develop the components of the system through the prototype plant to commercial exploitation. The consortium, known as the Clean Coal Power Generation Group (CCPGG), is undertaking a program of activity aimed at achieving a design specification for a 75 MWe prototype integrated plant by March, 1996. Component development consists of both the establishment of new components, such as the PFBG and the hot gas clean up system, and specific development of already established components, such as the CFBC, raw gas cooler, heat recovery steam generator (HRSG) and gas turbine. This paper discusses the component development activities and indicates the expected performance and economics of both the prototype and commercial plants. In addition, the strategy for component development and achievement of the specification for a 75 MWe prototype integrated plant is described.

  19. Compound cycle engine program

    NASA Technical Reports Server (NTRS)

    Bobula, G. A.; Wintucky, W. T.; Castor, J. G.

    1986-01-01

    The Compound Cycle Engine (CCE) is a highly turbocharged, power compounded power plant which combines the lightweight pressure rise capability of a gas turbine with the high efficiency of a diesel. When optimized for a rotorcraft, the CCE will reduce fuel burned for a typical 2 hr (plus 30 min reserve) mission by 30 to 40 percent when compared to a conventional advanced technology gas turbine. The CCE can provide a 50 percent increase in range-payload product on this mission. A program to establish the technology base for a Compound Cycle Engine is presented. The goal of this program is to research and develop those technologies which are barriers to demonstrating a multicylinder diesel core in the early 1990's. The major activity underway is a three-phased contract with the Garrett Turbine Engine Company to perform: (1) a light helicopter feasibility study, (2) component technology development, and (3) lubricant and material research and development. Other related activities are also presented.

  20. Sulphur geodynamic cycle

    PubMed Central

    Kagoshima, Takanori; Sano, Yuji; Takahata, Naoto; Maruoka, Teruyuki; Fischer, Tobias P.; Hattori, Keiko

    2015-01-01

    Evaluation of volcanic and hydrothermal fluxes to the surface environments is important to elucidate the geochemical cycle of sulphur and the evolution of ocean chemistry. This paper presents S/3He ratios of vesicles in mid-ocean ridge (MOR) basalt glass together with the ratios of high-temperature hydrothermal fluids to calculate the sulphur flux of 100 Gmol/y at MOR. The S/3He ratios of high-temperature volcanic gases show sulphur flux of 720 Gmol/y at arc volcanoes (ARC) with a contribution from the mantle of 2.9%, which is calculated as 21 Gmol/y. The C/S flux ratio of 12 from the mantle at MOR and ARC is comparable to the C/S ratio in the surface inventory, which suggests that these elements in the surface environments originated from the upper mantle. PMID:25660256

  1. The Pyrogenic Carbon Cycle

    NASA Astrophysics Data System (ADS)

    Bird, Michael I.; Wynn, Jonathan G.; Saiz, Gustavo; Wurster, Christopher M.; McBeath, Anna

    2015-05-01

    Pyrogenic carbon (PyC; includes soot, char, black carbon, and biochar) is produced by the incomplete combustion of organic matter accompanying biomass burning and fossil fuel consumption. PyC is pervasive in the environment, distributed throughout the atmosphere as well as soils, sediments, and water in both the marine and terrestrial environment. The physicochemical characteristics of PyC are complex and highly variable, dependent on the organic precursor and the conditions of formation. A component of PyC is highly recalcitrant and persists in the environment for millennia. However, it is now clear that a significant proportion of PyC undergoes transformation, translocation, and remineralization by a range of biotic and abiotic processes on comparatively short timescales. Here we synthesize current knowledge of the production, stocks, and fluxes of PyC as well as the physical and chemical processes through which it interacts as a dynamic component of the global carbon cycle.

  2. Deep sulfur cycle

    NASA Astrophysics Data System (ADS)

    Shimizu, N.; Mandeville, C. W.

    2009-12-01

    Geochemical cycle of sulfur in near-surface reservoirs has been a subject of intense studies for decades. It has been shown that sulfur isotopic compositions of sedimentary sulfides and sulfates record interactions of the atmosphere, hydrosphere, biosphere and lithosphere, with δ34S of sedimentary sulfides continuously decreasing from 0‰ toward present-day values of ~-30 to -40‰ over the Phanerozoic (e.g., Canfield, 2004). It has also been shown that microbial reduction of the present-day seawater sulfate (δ34S=+21‰) results in large shifts in isotopic compositions of secondary pyrites in altered oceanic crust (to δ34S=-70‰: Rouxel et al., 2009). How much of these near surface isotopic variations survive during deep geochemical cycle of sulfur interacting with the mantle infinite reservoir with δ34S=0‰? Could extent of their survival be used as a tracer of processes and dynamics involved in deep geochemical cycle? As a first step toward answering these questions, δ34S was determined in-situ using a Cameca IMS 1280 ion microprobe at Woods Hole Oceanographic Institution in materials representing various domains of deep geochemical cycle. They include pyrites in altered MORB as potential subducting materials and pyrites in UHP eclogites as samples that have experienced subduction zone processes, and mantle-derived melts are represented by olivine-hosted melt inclusions in MORB and those in IAB, and undegassed submarine OIB glasses. Salient features of the results include: (1) pyrites in altered MORB (with O. Rouxel; from ODP site 801 and ODP Hole 1301B) range from -70 to +19‰, (2) pyrites in UHP eclogites from the Western Gneiss Region, Norway (with B. Hacker and A. Kylander-Clark) show a limited overall range from -3.4 to + 2.8‰ among five samples, with one of them covering almost the entire range, indicating limited scale lengths of isotopic equilibration during subduction, (3) olivine-hosted melt inclusions in arc basalts from Galunggung (-2

  3. Variable cycle engine

    SciTech Connect

    Adamson, A.P.; Sprunger, E.V.

    1980-09-16

    A variable cycle turboshaft engine includes a remote fan system and respective high and low pressure systems for selectively driving the fan system in such a manner as to provide VTOL takeoff capability and minimum specific fuel consumption (SFC) at cruise and loiter conditions. For takeoff the fan system is primarily driven by the relatively large low pressure system whose combustor receives the motive fluid from a core bypass duct and, for cruise and loiter conditions, the fan system is driven by both a relatively small high pressure core and the low pressure system with its combustor inoperative. A mixer is disposed downstream of the high pressure system for mixing the relatively cold air from the bypass duct and the relatively hot air from the core prior to its flow to the low pressure turbine.

  4. Activity Cycles in Stars

    NASA Technical Reports Server (NTRS)

    Hathaway, David H.

    2009-01-01

    Starspots and stellar activity can be detected in other stars using high precision photometric and spectrometric measurements. These observations have provided some surprises (starspots at the poles - sunspots are rarely seen poleward of 40 degrees) but more importantly they reveal behaviors that constrain our models of solar-stellar magnetic dynamos. The observations reveal variations in cycle characteristics that depend upon the stellar structure, convection zone dynamics, and rotation rate. In general, the more rapidly rotating stars are more active. However, for stars like the Sun, some are found to be inactive while nearly identical stars are found to be very active indicating that periods like the Sun's Maunder Minimum (an inactive period from 1645 to 1715) are characteristic of Sun-like stars.

  5. Sulphur geodynamic cycle

    NASA Astrophysics Data System (ADS)

    Kagoshima, Takanori; Sano, Yuji; Takahata, Naoto; Maruoka, Teruyuki; Fischer, Tobias P.; Hattori, Keiko

    2015-02-01

    Evaluation of volcanic and hydrothermal fluxes to the surface environments is important to elucidate the geochemical cycle of sulphur and the evolution of ocean chemistry. This paper presents S/3He ratios of vesicles in mid-ocean ridge (MOR) basalt glass together with the ratios of high-temperature hydrothermal fluids to calculate the sulphur flux of 100 Gmol/y at MOR. The S/3He ratios of high-temperature volcanic gases show sulphur flux of 720 Gmol/y at arc volcanoes (ARC) with a contribution from the mantle of 2.9%, which is calculated as 21 Gmol/y. The C/S flux ratio of 12 from the mantle at MOR and ARC is comparable to the C/S ratio in the surface inventory, which suggests that these elements in the surface environments originated from the upper mantle.

  6. Sulphur geodynamic cycle.

    PubMed

    Kagoshima, Takanori; Sano, Yuji; Takahata, Naoto; Maruoka, Teruyuki; Fischer, Tobias P; Hattori, Keiko

    2015-01-01

    Evaluation of volcanic and hydrothermal fluxes to the surface environments is important to elucidate the geochemical cycle of sulphur and the evolution of ocean chemistry. This paper presents S/(3)He ratios of vesicles in mid-ocean ridge (MOR) basalt glass together with the ratios of high-temperature hydrothermal fluids to calculate the sulphur flux of 100 Gmol/y at MOR. The S/(3)He ratios of high-temperature volcanic gases show sulphur flux of 720 Gmol/y at arc volcanoes (ARC) with a contribution from the mantle of 2.9%, which is calculated as 21 Gmol/y. The C/S flux ratio of 12 from the mantle at MOR and ARC is comparable to the C/S ratio in the surface inventory, which suggests that these elements in the surface environments originated from the upper mantle. PMID:25660256

  7. Coupled quantum Otto cycle.

    PubMed

    Thomas, George; Johal, Ramandeep S

    2011-03-01

    We study the one-dimensional isotropic Heisenberg model of two spin-1/2 systems as a quantum heat engine. The engine undergoes a four-step Otto cycle where the two adiabatic branches involve changing the external magnetic field at a fixed value of the coupling constant. We find conditions for the engine efficiency to be higher than in the uncoupled model; in particular, we find an upper bound which is tighter than the Carnot bound. A domain of parameter values is pointed out which was not feasible in the interaction-free model. Locally, each spin seems to cause a flow of heat in a direction opposite to the global temperature gradient. This feature is explained by an analysis of the local effective temperature of the spins. PMID:21517482

  8. Nutrient Cycling Study

    SciTech Connect

    Peter A. Pryfogle

    2005-09-01

    The particular goal of this study is to develop measurement techniques for understanding how consortia of organisms from geothermal facilities utilize sulfur and iron for metabolic activity; and in turn, what role that activity plays in initiating or promoting the development of a biofilm on plant substrates. Sulfur cycling is of interest because sulfur is produced in the resource. Iron is found in some of the steel formulations used in plant components and is also added as chemical treatment for reducing sulfide emissions from the plants. This report describes the set-up and operation of a bioreactor for evaluating the response of colonies of geothermal organisms to changes in nutrient and environmental conditions. Data from initial experiments are presented and plans for future testing is discussed.

  9. Open cycle thermoacoustics

    SciTech Connect

    Reid, Robert Stowers

    2000-01-01

    A new type of thermodynamic device combining a thermodynamic cycle with the externally applied steady flow of an open thermodynamic process is discussed and experimentally demonstrated. The gas flowing through this device can be heated or cooled in a series of semi-open cyclic steps. The combination of open and cyclic flows makes possible the elimination of some or all of the heat exchangers (with their associated irreversibility). Heat is directly exchanged with the process fluid as it flows through the device when operating as a refrigerator, producing a staging effect that tends to increase First Law thermodynamic efficiency. An open-flow thermoacoustic refrigerator was built to demonstrate this concept. Several approaches are presented that describe the physical characteristics of this device. Tests have been conducted on this refrigerator with good agreement with a proposed theory.

  10. Krebs Cycle Wordsearch

    NASA Astrophysics Data System (ADS)

    Helser, Terry L.

    2001-04-01

    This puzzle embeds 46 names, terms, abbreviations, and acronyms about the citric acid (Krebs) cycle in a 14- x 17-letter matrix. A descriptive narrative beside it describes important features of the pathway. All the terms a student needs to find are embedded there with the first letter followed by underlined blanks to be completed. Therefore, the students usually must find the terms to know how to spell them, correctly fill in the blanks in the narrative with the terms, and then find and highlight the terms in the letter matrix. When all are found, the 24 unused letters complete a sentence that describes a major feature of this central pathway. The puzzle may be used as homework, an extra-credit project, or a group project in the classroom in any course where basic metabolism is learned. It disguises as fun the hard work needed to learn the names of the intermediates, enzymes, and cofactors.

  11. Ocean iron cycle

    NASA Astrophysics Data System (ADS)

    Boyd, Philip W.

    Interest in the biogeochemical cycle of iron has grown rapidly over the last two decades, due to the potential role of this element in modulating global climate in the geological past and ocean productivity in the present day. This trace metal has a disproportionately large effect (1 × 105 C:Fe) on photosynthetic carbon fixation by phytoplankton. In around one third of the open ocean, so-called high-nitrate low-chlorophyll (HNLC) regions, the resident phytoplankton have low growth rates despite an abundance of plant nutrients. This is due to the low supply of iron. Iron is present in the ocean in three phases, dissolved, colloidal, and particulate (biogenic and lithogenic). However, iron chemistry is complex with interactions between chemistry and biology such as the production of iron-binding siderophores by oceanic bacteria. This results in the interplay of inorganic chemistry, photochemistry, and organic complexation. Sources of new iron include dust deposition, upwelling of iron-rich deep waters, and the resuspension and lateral transport of sediments. Sinks for iron are mainly biological as evidenced by the vertical nutrient-like profile for dissolved iron in the ocean. Iron is rapidly recycled by the upper ocean biota within a so-called "ferrous wheel." The fe ratio [(new iron)/(new + regenerated iron)] provides an index of the relative supply of iron to the biota by new versus recycled iron. Over the last 15 years, interest in the potential role of iron in shaping climate in the geological past resulted in some of the most ambitious experiments in oceanography: large-scale (i.e., 50-1000 km2) iron enrichment of HNLC waters. They have provided valuable insights into how iron supply influences the biogeochemical cycles of elements such as carbon, sulfur, silicon, nitrogen, and phosphate.

  12. The Kalina cycle and similar cycles for geothermal power production

    SciTech Connect

    Bliem, C.J.

    1988-09-01

    This report contains a brief discussion of the mechanics of the Kalina cycle and ideas to extend the concept to other somewhat different cycles. A modified cycle which has a potential heat rejection advantage but little or no performance improvement is discussed. Then, the results of the application of the Kalina cycle and the modified cycle to a geothermal application (360/degree/F resource) are discussed. The results are compared with published results for the Kalina cycle with high temperature sources and estimates about performance at the geothermal temperatures. Finally, the conclusions of this scoping work are given along with recommendations of the direction of future work in this area. 11 refs., 4 figs., 1 tab.

  13. Reproductive cycles of buffalo.

    PubMed

    Perera, B M A O

    2011-04-01

    The domestic water buffalo (Bubalus bubalis) has an important role in the agricultural economy of many developing countries in Asia, providing milk, meat and draught power. It is also used in some Mediterranean and Latin American countries as a source of milk and meat for specialized markets. Although the buffalo can adapt to harsh environments and live on poor quality forage, reproductive efficiency is often compromised by such conditions, resulting in late sexual maturity, long postpartum anoestrus, poor expression of oestrus, poor conception rates and long calving intervals. The age at puberty is influenced by genotype, nutrition, management and climate, and under favourable conditions occurs at 15-18 months in river buffalo and 21-24 months in swamp buffalo. The ovaries are smaller than in cattle and contain fewer primordial follicles. Buffalo are capable of breeding throughout the year, but in many countries a seasonal pattern of ovarian activity occurs. This is attributed in tropical regions to changes in rainfall resulting in feed availability or to temperature stress resulting in elevated prolactin secretion, and in temperate regions to changes in photoperiod and melatonin secretion. The mean length of the oestrous cycle is 21 days, with greater variation than observed in cattle. The signs of oestrus in buffalo are less overt than in cattle and homosexual behaviour between females is rare. The duration of oestrus is 5-27 h, with ovulation occurring 24-48 h (mean 34 h) after the onset of oestrus. The hormonal changes occurring in peripheral circulation are similar to those observed in cattle, but the peak concentrations of progesterone and oestradiol-17β are less. The number of follicular waves during an oestrous cycle varies from one to three and influences the length of the luteal phase as well as the inter-ovulatory interval. Under optimal conditions, dairy types managed with limited or no suckling resume oestrus cyclicity by 30-60 days after calving

  14. The Global Nitrogen Cycle

    NASA Astrophysics Data System (ADS)

    Galloway, J. N.

    2003-12-01

    Once upon a time nitrogen did not exist. Today it does. In the intervening time the universe was formed, nitrogen was created, the Earth came into existence, and its atmosphere and oceans were formed! In this analysis of the Earth's nitrogen cycle, I start with an overview of these important events relative to nitrogen and then move on to the more traditional analysis of the nitrogen cycle itself and the role of humans in its alteration.The universe is ˜15 Gyr old. Even after its formation, there was still a period when nitrogen did not exist. It took ˜300 thousand years after the big bang for the Universe to cool enough to create atoms; hydrogen and helium formed first. Nitrogen was formed in the stars through the process of nucleosynthesis. When a star's helium mass becomes great enough to reach the necessary pressure and temperature, helium begins to fuse into still heavier elements, including nitrogen.Approximately 10 Gyr elapsed before Earth was formed (˜4.5 Ga (billion years ago)) by the accumulation of pre-assembled materials in a multistage process. Assuming that N2 was the predominate nitrogen species in these materials and given that the temperature of space is -270 °C, N2 was probably a solid when the Earth was formed since its boiling point (b.p.) and melting point (m.p.) are -196 °C and -210 °C, respectively. Towards the end of the accumulation period, temperatures were probably high enough for significant melting of some of the accumulated material. The volcanic gases emitted by the resulting volcanism strongly influenced the surface environment. Nitrogen was converted from a solid to a gas and emitted as N2. Carbon and sulfur were probably emitted as CO and H2S (Holland, 1984). N2 is still the most common nitrogen volcanic gas emitted today at a rate of ˜2 TgN yr-1 (Jaffee, 1992).Once emitted, the gases either remained in the atmosphere or were deposited to the Earth's surface, thus continuing the process of biogeochemical cycling. The rate of

  15. Advanced regenerative absorption refrigeration cycles

    DOEpatents

    Dao, Kim

    1990-01-01

    Multi-effect regenerative absorption cycles which provide a high coefficient of performance (COP) at relatively high input temperatures. An absorber-coupled double-effect regenerative cycle (ADR cycle) (10) is provided having a single-effect absorption cycle (SEA cycle) (11) as a topping subcycle and a single-effect regenerative absorption cycle (1R cycle) (12) as a bottoming subcycle. The SEA cycle (11) includes a boiler (13), a condenser (21), an expansion device (28), an evaporator (31), and an absorber (40), all operatively connected together. The 1R cycle (12) includes a multistage boiler (48), a multi-stage resorber (51), a multisection regenerator (49) and also uses the condenser (21), expansion device (28) and evaporator (31) of the SEA topping subcycle (11), all operatively connected together. External heat is applied to the SEA boiler (13) for operation up to about 500 degrees F., with most of the high pressure vapor going to the condenser (21) and evaporator (31) being generated by the regenerator (49). The substantially adiabatic and isothermal functioning of the SER subcycle (12) provides a high COP. For higher input temperatures of up to 700 degrees F., another SEA cycle (111) is used as a topping subcycle, with the absorber (140) of the topping subcycle being heat coupled to the boiler (13) of an ADR cycle (10). The 1R cycle (12) itself is an improvement in that all resorber stages (50b-f) have a portion of their output pumped to boiling conduits (71a-f) through the regenerator (49), which conduits are connected to and at the same pressure as the highest pressure stage (48a) of the 1R multistage boiler (48).

  16. The Cycles of Math and Science.

    ERIC Educational Resources Information Center

    Sumrall, William J.; Rock, David

    2002-01-01

    Introduces lesson plans on cycles designed for middle school students. Activities include: (1) "Boiling and Evaporation"; (2) "Experimenting with Evaporation"; (3) "Condensation and the Water Cycle"; and (4) "Understanding Cycles". Explains the mathematical applications of cycles. (YDS)

  17. Glacial cycles and astronomical forcing

    SciTech Connect

    Muller, R.A.; MacDonald, G.J.

    1997-07-11

    Narrow spectral features in ocean sediment records offer strong evidence that the cycles of glaciation were driven by astronomical forces. Two million years ago, the cycles match the 41,000-year period of Earth`s obliquity. This supports the Croll/Milankovitch theory, which attributes the cycles to variations in insolation. But for the past million years, the spectrum is dominated by a single 100,000-year feature and is a poor match to the predictions of insolation models. The spectrum can be accounted for by a theory that derives the cycles of glaciation from variations in the inclination of Earth`s orbital plane.

  18. Rethinking the Ancient Sulfur Cycle

    NASA Astrophysics Data System (ADS)

    Fike, David A.; Bradley, Alexander S.; Rose, Catherine V.

    2015-05-01

    The sulfur biogeochemical cycle integrates the metabolic activity of multiple microbial pathways (e.g., sulfate reduction, disproportionation, and sulfide oxidation) along with abiotic reactions and geological processes that cycle sulfur through various reservoirs. The sulfur cycle impacts the global carbon cycle and climate primarily through the remineralization of organic carbon. Over geological timescales, cycling of sulfur is closely tied to the redox state of Earth's exosphere through the burial of oxidized (sulfate) and reduced (sulfide) sulfur species in marine sediments. Biological sulfur cycling is associated with isotopic fractionations that can be used to trace the fluxes through various metabolic pathways. The resulting isotopic data provide insights into sulfur cycling in both modern and ancient environments via isotopic signatures in sedimentary sulfate and sulfide phases. Here, we review the deep-time δ34S record of marine sulfates and sulfides in light of recent advances in understanding how isotopic signatures are generated by microbial activity, how these signatures are encoded in marine sediments, and how they may be altered following deposition. The resulting picture shows a sulfur cycle intimately coupled to ambient carbon cycling, where sulfur isotopic records preserved in sedimentary rocks are critically dependent on sedimentological and geochemical conditions (e.g., iron availability) during deposition.

  19. Self-organizing biochemical cycles

    NASA Technical Reports Server (NTRS)

    Orgel, L. E.; Bada, J. L. (Principal Investigator)

    2000-01-01

    I examine the plausibility of theories that postulate the development of complex chemical organization without requiring the replication of genetic polymers such as RNA. One conclusion is that theories that involve the organization of complex, small-molecule metabolic cycles such as the reductive citric acid cycle on mineral surfaces make unreasonable assumptions about the catalytic properties of minerals and the ability of minerals to organize sequences of disparate reactions. Another conclusion is that data in the Beilstein Handbook of Organic Chemistry that have been claimed to support the hypothesis that the reductive citric acid cycle originated as a self-organized cycle can more plausibly be interpreted in a different way.

  20. Recycling and Life Cycle Issues

    SciTech Connect

    Das, Sujit

    2010-01-01

    This chapter addresses recycling and life cycle considerations related to the growing use of lightweight materials in vehicles. The chapter first addresses the benefit of a life cycle perspective in materials choice, and the role that recycling plays in reducing energy inputs and environmental impacts in a vehicle s life cycle. Some limitations of life cycle analysis and results of several vehicle- and fleet-level assessments are drawn from published studies. With emphasis on lightweight materials such as aluminum, magnesium, and polymer composites, the status of the existing recycling infrastructure and technological challenges being faced by the industry also are discussed.

  1. Regenerative superheated steam turbine cycles

    NASA Technical Reports Server (NTRS)

    Fuller, L. C.; Stovall, T. K.

    1980-01-01

    PRESTO computer program was developed to analyze performance of wide range of steam turbine cycles with special attention given to regenerative superheated steam turbine cycles. It can be used to model standard turbine cycles, including such features as process steam extraction, induction and feedwater heating by external sources, peaking, and high back pressure. Expansion line efficiencies, exhaust loss, leakages, mechanical losses, and generator losses are used to calculate cycle heat rate and generator output. Program provides power engineer with flexible aid for design and analysis of steam turbine systems.

  2. The Global Nitrogen Cycle

    NASA Astrophysics Data System (ADS)

    Galloway, J. N.

    2003-12-01

    Once upon a time nitrogen did not exist. Today it does. In the intervening time the universe was formed, nitrogen was created, the Earth came into existence, and its atmosphere and oceans were formed! In this analysis of the Earth's nitrogen cycle, I start with an overview of these important events relative to nitrogen and then move on to the more traditional analysis of the nitrogen cycle itself and the role of humans in its alteration.The universe is ˜15 Gyr old. Even after its formation, there was still a period when nitrogen did not exist. It took ˜300 thousand years after the big bang for the Universe to cool enough to create atoms; hydrogen and helium formed first. Nitrogen was formed in the stars through the process of nucleosynthesis. When a star's helium mass becomes great enough to reach the necessary pressure and temperature, helium begins to fuse into still heavier elements, including nitrogen.Approximately 10 Gyr elapsed before Earth was formed (˜4.5 Ga (billion years ago)) by the accumulation of pre-assembled materials in a multistage process. Assuming that N2 was the predominate nitrogen species in these materials and given that the temperature of space is -270 °C, N2 was probably a solid when the Earth was formed since its boiling point (b.p.) and melting point (m.p.) are -196 °C and -210 °C, respectively. Towards the end of the accumulation period, temperatures were probably high enough for significant melting of some of the accumulated material. The volcanic gases emitted by the resulting volcanism strongly influenced the surface environment. Nitrogen was converted from a solid to a gas and emitted as N2. Carbon and sulfur were probably emitted as CO and H2S (Holland, 1984). N2 is still the most common nitrogen volcanic gas emitted today at a rate of ˜2 TgN yr-1 (Jaffee, 1992).Once emitted, the gases either remained in the atmosphere or were deposited to the Earth's surface, thus continuing the process of biogeochemical cycling. The rate of

  3. The nitrogen cycle.

    PubMed

    Stein, Lisa Y; Klotz, Martin G

    2016-02-01

    Nitrogen is the fourth most abundant element in cellular biomass, and it comprises the majority of Earth's atmosphere. The interchange between inert dinitrogen gas (N2) in the extant atmosphere and 'reactive nitrogen' (those nitrogen compounds that support, or are products of, cellular metabolism and growth) is entirely controlled by microbial activities. This was not the case, however, in the primordial atmosphere, when abiotic reactions likely played a significant role in the inter-transformation of nitrogen oxides. Although such abiotic reactions are still important, the extant nitrogen cycle is driven by reductive fixation of dinitrogen and an enzyme inventory that facilitates dinitrogen-producing reactions. Prior to the advent of the Haber-Bosch process (the industrial fixation of N2 into ammonia, NH3) in 1909, nearly all of the reactive nitrogen in the biosphere was generated and recycled by microorganisms. Although the Haber-Bosch process more than quadrupled the productivity of agricultural crops, chemical fertilizers and other anthropogenic sources of fixed nitrogen now far exceed natural contributions, leading to unprecedented environmental degradation. PMID:26859274

  4. Organic rankine cycle fluid

    SciTech Connect

    Brasz, Joost J.; Jonsson, Ulf J.

    2006-09-05

    A method of operating an organic rankine cycle system wherein a liquid refrigerant is circulated to an evaporator where heat is introduced to the refrigerant to convert it to vapor. The vapor is then passed through a turbine, with the resulting cooled vapor then passing through a condenser for condensing the vapor to a liquid. The refrigerant is one of CF.sub.3CF.sub.2C(O)CF(CF.sub.3).sub.2, (CF.sub.3).sub.2 CFC(O)CF(CF.sub.3).sub.2, CF.sub.3(CF.sub.2).sub.2C(O)CF(CF.sub.3).sub.2, CF.sub.3(CF.sub.2).sub.3C(O)CF(CG.sub.3).sub.2, CF.sub.3(CF.sub.2).sub.5C(O)CF.sub.3, CF.sub.3CF.sub.2C(O)CF.sub.2CF.sub.2CF.sub.3, CF.sub.3C(O)CF(CF.sub.3).sub.2.

  5. The Photosynthetic Cycle

    DOE R&D Accomplishments Database

    Calvin, Melvin

    1955-03-21

    A cyclic sequence of transformations, including the carboxylation of RuDP (ribulose diphosphate) and its re-formation, has been deduced as the route for the creation of reduced carbon compounds in photosynthetic organisms. With the demonstration of RuDP as substrate for the carboxylation in a cell-free system, each of the reactions has now been carried out independently in vitro. Further purification of this last enzyme system has confirmed the deduction that the carboxylation of RuDP leads directly to the two molecules of PGA (phosphoglyceric acid) involving an internal dismutation and suggesting the name "carboxydismutase" for the enzyme. As a consequence of this knowledge of each of the steps in the photosynthetic CO{sub 2} reduction cycle, it is possible to define the reagent requirements to maintain it. The net requirement for the reduction of one molecule of CO{sub 2} is four equivalents of [H]and three molecules of ATP (adenine triphosphate). These must ultimately be supplied by the photochemical reaction. Some possible ways in which this may be accomplished are discussed.

  6. Reproductive cycles of deer.

    PubMed

    Asher, G W

    2011-04-01

    The cervids are a complex assemblage of taxa showing extreme diversity in morphology, physiology, ecology and geographical distribution. Reproductive strategies adopted by various species are also diverse, and include a range from highly seasonal to completely aseasonal birth patterns. The recent growth in knowledge on cervid reproduction is strongly biased towards the larger-bodied, gregarious mixed grazer-browser species that have adapted well to human management and commercialisation. These species tend to represent 'K-selected' climax species characterised by very productive annual breeding success, singleton births and long breeding life (10+ years). Conversely, we know relatively little about the reproductive patterns of the 'r-selected' smaller-bodied, solitary (and often highly territorial), forest-dwelling browser species, often characterised by great fecundity (twinning) and shorter breeding life (<10 years). This group includes many of the endangered cervid taxa. This review extends earlier reviews to include more recent work on cervid reproductive cycles, particularly in relation to environmental factors influencing gestation length. PMID:20884138

  7. Wilson Cycle studies

    NASA Technical Reports Server (NTRS)

    Burke, Kevin

    1987-01-01

    The main activity relating to the study during this half year was a three week field trip to study Chinese sedimentary basins (June 10 to July 3, 1986) at no cost to the project. This study, while of a reconnaissance character, permitted progress in understanding how the processes of island arc-collision and micro-continental collision operated during the Paleozoic in far western China (especially the Junggar and Tarim basins and in the intervening Tien Shan Mountains). These effects of the continuing collision of India and Asia on the area were also studied. Most specifically, these result in the elevation of the Tien Shan to more than 4 km above sea level and the depression of Turfan to move 150m below sea level. Both thrusting and large-scale strike-slip motion are important in producing these elevation changes. Some effort during the half year was also devoted to the study of greenstone-belts in terms of the Wilson Cycle.

  8. Biomass Gasification Combined Cycle

    SciTech Connect

    Judith A. Kieffer

    2000-07-01

    Gasification combined cycle continues to represent an important defining technology area for the forest products industry. The ''Forest Products Gasification Initiative'', organized under the Industry's Agenda 2020 technology vision and supported by the DOE ''Industries of the Future'' program, is well positioned to guide these technologies to commercial success within a five-to ten-year timeframe given supportive federal budgets and public policy. Commercial success will result in significant environmental and renewable energy goals that are shared by the Industry and the Nation. The Battelle/FERCO LIVG technology, which is the technology of choice for the application reported here, remains of high interest due to characteristics that make it well suited for integration with the infrastructure of a pulp production facility. The capital cost, operating economics and long-term demonstration of this technology area key input to future economically sustainable projects and must be verified by the 200 BDT/day demonstration facility currently operating in Burlington, Vermont. The New Bern application that was the initial objective of this project is not currently economically viable and will not be implemented at this time due to several changes at and around the mill which have occurred since the inception of the project in 1995. The analysis shows that for this technology, and likely other gasification technologies as well, the first few installations will require unique circumstances, or supportive public policies, or both to attract host sites and investors.

  9. The closed fuel cycle

    SciTech Connect

    Froment, Antoine; Gillet, Philippe

    2007-07-01

    Available in abstract form only. Full text of publication follows: The fast growth of the world's economy coupled with the need for optimizing use of natural resources, for energy security and for climate change mitigation make energy supply one of the 21. century most daring challenges. The high reliability and efficiency of nuclear energy, its competitiveness in an energy market undergoing a new oil shock are as many factors in favor of the 'renaissance' of this greenhouse gas free energy. Over 160,000 tHM of LWR1 and AGR2 Used Nuclear Fuel (UNF) have already been unloaded from the reactor cores corresponding to 7,000 tons discharged per year worldwide. By 2030, this amount could exceed 400,000 tHM and annual unloading 14,000 tHM/year. AREVA believes that closing the nuclear fuel cycle through the treatment and recycling of Used Nuclear Fuel sustains the worldwide nuclear power expansion. It is an economically sound and environmentally responsible choice, based on the preservation of natural resources through the recycling of used fuel. It furthermore provides a safe and secure management of wastes while significantly minimizing the burden left to future generations. (authors)

  10. Specific cell cycle synchronization with butyrate and cell cycle analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Synchronized cells have been invaluable for many kinds of cell cycle and cell proliferation studies. Butyrate induces cell cycle arrest and apoptosis in MDBK cells. To explore the possibility of using butyrate-blocked cells to obtain synchronized cells, we investigated the property of the cell cyc...

  11. Life Cycle of Stars

    NASA Technical Reports Server (NTRS)

    1999-01-01

    In this stunning picture of the giant galactic nebula NGC 3603, the crisp resolution of NASA's Hubble Space Telescope captures various stages of the life cycle of stars in one single view. To the upper left of center is the evolved blue supergiant called Sher 25. The star has a unique circumstellar ring of glowing gas that is a galactic twin to the famous ring around the supernova 1987A. The grayish-bluish color of the ring and the bipolar outflows (blobs to the upper right and lower left of the star) indicates the presence of processed (chemically enriched) material. Near the center of the view is a so-called starburst cluster dominated by young, hot Wolf-Rayet stars and early O-type stars. A torrent of ionizing radiation and fast stellar winds from these massive stars has blown a large cavity around the cluster. The most spectacular evidence for the interaction of ionizing radiation with cold molecular-hydrogen cloud material are the giant gaseous pillars to the right of the cluster. These pillars are sculptured by the same physical processes as the famous pillars Hubble photographed in the M16 Eagle Nebula. Dark clouds at the upper right are so-called Bok globules, which are probably in an earlier stage of star formation. To the lower left of the cluster are two compact, tadpole-shaped emission nebulae. Similar structures were found by Hubble in Orion, and have been interpreted as gas and dust evaporation from possibly protoplanetary disks (proplyds). This true-color picture was taken on March 5, 1999 with the Wide Field Planetary Camera 2.

  12. Reducing Life-Cycle Costs.

    ERIC Educational Resources Information Center

    Roodvoets, David L.

    2003-01-01

    Presents factors to consider when determining roofing life-cycle costs, explaining that costs do not tell the whole story; discussing components that should go into the decision (cost, maintenance, energy use, and environmental costs); and concluding that important elements in reducing life-cycle costs include energy savings through increased…

  13. Variations on the Zilch Cycle

    ERIC Educational Resources Information Center

    Binder, P.-M.; Tanoue, C. K. S.

    2013-01-01

    Thermo dynamic cycles in introductory physics courses are usually made up from a small number of permutations of isothermal, adiabatic, and constant-pressure and volume quasistatic strokes, with the working fluid usually being an ideal gas. Among them we find the Carnot, Stirling, Otto, Diesel, and Joule-Brayton cycles; in more advanced courses,…

  14. Nuclear fuel cycle information workshop

    SciTech Connect

    Not Available

    1983-01-01

    This overview of the nuclear fuel cycle is divided into three parts. First, is a brief discussion of the basic principles of how nuclear reactors work; second, is a look at the major types of nuclear reactors being used and world-wide nuclear capacity; and third, is an overview of the nuclear fuel cycle and the present industrial capability in the US.

  15. Seclusion and the lunar cycles.

    PubMed

    Mason, T

    1997-06-01

    1. The lunar cycle's influence over psychological disturbances in the human being is known as the Transylvanian effect. 2. Seclusion is used predominantly for the control and management of violence and aggression in patients. 3. If the Transylvanian effect is supported, a relationship between lunar cycles and the use of seclusion should exist; no such correlation, however, was found in this study. PMID:9189846

  16. The water cycle for kids

    USGS Publications Warehouse

    Neno, Stephanie; Morgan, Jim; Zonolli, Gabriele; Perlman, Howard; Gonthier, Gerard

    2013-01-01

    The U.S. Geological Survey (USGS) and the Food and Agriculture Organization of the United Nations (FAO) have created a water-cycle diagram for use in elementary and middle schools. The diagram is available in many languages. This diagram is part of the USGS's Water Science School, in which the water cycle is described in detail.

  17. Life Cycle of a Pencil.

    ERIC Educational Resources Information Center

    Reeske, Mike

    2000-01-01

    Explains a project called "Life Cycle of a Pencil" which was developed by the National Science Teachers Association (NSTA) and the U.S. Environmental Protection Agency (USEPA). Describes the life cycle of a pencil in stages starting from the first stage of design to the sixth stage of product disposal. (YDS)

  18. The photochemical cycle of bacteriorhodopsin

    NASA Technical Reports Server (NTRS)

    Lozier, R. H.; Niederberger, W.

    1977-01-01

    The reaction cycle of bacteriorhodopsin in the purple membrane isolated from Halobacterium halobium has been studied by optical absorption spectroscopy using low-temperature and flash kinetic techniques. After absorption of light, bacteriorhodopsin passes through at least five distinct intermediates. The temperature and pH dependence of the absorbance changes suggests that branch points and/or reversible steps exist in this cycle. Flash spectroscopy in the presence of a pH-indicating dye shows that the transient release of a proton accompanies the photoreaction cycle. The proton release occurs from the exterior and the uptake is on the cytoplasmic side of the membrane, as required by the function of bacteriorhodopsin as a light-driven proton pump. Proton translocating steps connecting release and uptake are indicated by deuterium isotope effects on the kinetics of the cycle. The rapid decay of a light-induced linear dichroism shows that a chromophore orientation change occurs during the reaction cycle.

  19. Fuel cycle cost uncertainty from nuclear fuel cycle comparison

    SciTech Connect

    Li, J.; McNelis, D.; Yim, M.S.

    2013-07-01

    This paper examined the uncertainty in fuel cycle cost (FCC) calculation by considering both model and parameter uncertainty. Four different fuel cycle options were compared in the analysis including the once-through cycle (OT), the DUPIC cycle, the MOX cycle and a closed fuel cycle with fast reactors (FR). The model uncertainty was addressed by using three different FCC modeling approaches with and without the time value of money consideration. The relative ratios of FCC in comparison to OT did not change much by using different modeling approaches. This observation was consistent with the results of the sensitivity study for the discount rate. Two different sets of data with uncertainty range of unit costs were used to address the parameter uncertainty of the FCC calculation. The sensitivity study showed that the dominating contributor to the total variance of FCC is the uranium price. In general, the FCC of OT was found to be the lowest followed by FR, MOX, and DUPIC. But depending on the uranium price, the FR cycle was found to have lower FCC over OT. The reprocessing cost was also found to have a major impact on FCC.

  20. Variations on the Zilch Cycle

    NASA Astrophysics Data System (ADS)

    Binder, P.-M.; Tanoue, C. K. S.

    2013-10-01

    Thermo dynamic cycles in introductory physics courses are usually made up from a small number of permutations of isothermal, adiabatic, and constant-pressure and volume quasistatic strokes, with the working fluid usually being an ideal gas. Among them we find the Carnot, Stirling, Otto, Diesel, and Joule-Brayton cycles; in more advanced courses, steam cycles and refrigerators based on real working fluids are often introduced. Any additional cycles made up from the same simple strokes, and any extended analysis of known cycles, are welcome additions to the teaching repertory, as they provide more opportunities for practice and discussion. Our purpose in this note is to extend the analysis of the zilch cycle, introduced in Ref. 1, by presenting its TS diagram and by proposing several variations that do not contain adiabatic strokes, thus allowing a simpler mathematical treatment. As a bonus, we also provide results that make it possible to represent practically any elementary ideal-gas cycle in a TS diagram.

  1. Hund{close_quote}s-rule effects in the {ital f}{sup 1}-{ital f}{sup 2} Anderson impurity model: Renormalization of Hund{close_quote}s-rule Coulomb interactions down to low energies

    SciTech Connect

    Landgraf, J.M.; Rasul, J.W.

    1996-10-01

    We examine the problem of an Anderson impurity model where the lowest configurations are {ital f}{sup 1} and {ital f}{sup 2}, with a Hund{close_quote}s-rule splitting (corresponding to Hunds first rule) present. We calculate (using the 1/{ital N} expansion) the single-particle spectrum in the limit of large ferromagnetic triplet-singlet splitting, and find the spectrum to be mostly equivalent to that of a zero Hund{close_quote}s-rule splitting model with reduced hybridization. At low energies, however, additional features arise on a scale given by the Kondo temperature. The results illustrate how the effects of a strong Hund{close_quote}s-rule interaction are renormalized down to low energies, and help understand how a heavy fermion band structure can be resilient against Hund{close_quote}s-rule couplings. {copyright} {ital 1996 The American Physical Society.}

  2. The Manuel Lujan Jr. Neutron Scattering Center (LANSCE) experiment reports 1993 run cycle. Progress report

    SciTech Connect

    Farrer, R.; Longshore, A.

    1995-06-01

    This year the Manuel Lujan Jr. Neutron Scattering Center (LANSCE) ran an informal user program because the US Department of Energy planned to close LANSCE in FY1994. As a result, an advisory committee recommended that LANSCE scientists and their collaborators complete work in progress. At LANSCE, neutrons are produced by spallation when a pulsed, 800-MeV proton beam impinges on a tungsten target. The proton pulses are provided by the Clinton P. Anderson Meson Physics Facility (LAMPF) accelerator and a associated Proton Storage Ring (PSR), which can Iter the intensity, time structure, and repetition rate of the pulses. The LAMPF protons of Line D are shared between the LANSCE target and the Weapons Neutron Research (WNR) facility, which results in LANSCE spectrometers being available to external users for unclassified research about 80% of each annual LAMPF run cycle. Measurements of interest to the Los Alamos National Laboratory (LANL) may also be performed and may occupy up to an additional 20% of the available beam time. These experiments are reviewed by an internal program advisory committee. This year, a total of 127 proposals were submitted. The proposed experiments involved 229 scientists, 57 of whom visited LANSCE to participate in measurements. In addition, 3 (nuclear physics) participating research teams, comprising 44 scientists, carried out experiments at LANSCE. Instrument beam time was again oversubscribed, with 552 total days requested an 473 available for allocation.

  3. Cheng Cycle reporting high availability

    SciTech Connect

    Not Available

    1986-02-01

    Operating results from the Cheng Cycle cogeneration plants at San Jose State University and at Sunkist Growers in Ontario, California look very good so far, according to officials of International Power Technology (IPT). Both plants contain IPT's Cheng Cycle Series 7-Cogen system, which produces between 3 and 6 MW of electricity and up to 45,000 pounds of steam per hour. The company is developing the patented technology as an improved combined cycle system which can produce steam and electricity under widely varying load demands.

  4. Self-organizing biochemical cycles

    PubMed Central

    Orgel, Leslie E.

    2000-01-01

    I examine the plausibility of theories that postulate the development of complex chemical organization without requiring the replication of genetic polymers such as RNA. One conclusion is that theories that involve the organization of complex, small-molecule metabolic cycles such as the reductive citric acid cycle on mineral surfaces make unreasonable assumptions about the catalytic properties of minerals and the ability of minerals to organize sequences of disparate reactions. Another conclusion is that data in the Beilstein Handbook of Organic Chemistry that have been claimed to support the hypothesis that the reductive citric acid cycle originated as a self-organized cycle can more plausibly be interpreted in a different way. PMID:11058157

  5. Our World: The Rock Cycle

    NASA Video Gallery

    Find out how rocks brought to Earth by the Apollo astronauts have helped NASA learn more about the rock cycle. Compare igneous, sedimentary and metamorphic rocks found on Earth to three types of ro...

  6. National Urea Cycle Disorders Foundation

    MedlinePlus

    ... urea cycle in regulating nitric oxide in the human body, the study is being conducted by Dr. ... a major discovery in ASA deficiency that transforms human science. The research has been published in Nature ...

  7. Cell cycle control in Alphaproteobacteria.

    PubMed

    Collier, Justine

    2016-04-01

    Alphaproteobacteria include many medically and environmentally important organisms. Despite the diversity of their niches and lifestyles, from free-living to host-associated, they usually rely on very similar mechanisms to control their cell cycles. Studies on Caulobacter crescentus still lay the foundation for understanding the molecular details of pathways regulating DNA replication and cell division and coordinating these two processes with other events of the cell cycle. This review highlights recent discoveries on the regulation and the mode of action of conserved global regulators and small molecules like c-di-GMP and (p)ppGpp, which play key roles in cell cycle control. It also describes several newly identified mechanisms that modulate cell cycle progression in response to stresses or environmental conditions. PMID:26871482

  8. Limit cycle vibrations in turbomachinery

    NASA Technical Reports Server (NTRS)

    Ryan, S. G.

    1991-01-01

    The focus is on an examination of rotordynamic systems which are simultaneously susceptible to limit cycle instability and subharmonic response. Characteristics of each phenomenon are determined as well as their interrelationship. A normalized, single mass rotor model is examined as well as a complex model of the high pressure fuel turbopump and the Space Shuttle Main Engine. Entrainment of limit cycle instability by subharmonic response is demonstrated for both models. The nonuniqueness of the solution is also demonstrated.

  9. Finding long cycles in graphs

    NASA Astrophysics Data System (ADS)

    Marinari, Enzo; Semerjian, Guilhem; van Kerrebroeck, Valery

    2007-06-01

    We analyze the problem of discovering long cycles inside a graph. We propose and test two algorithms for this task. The first one is based on recent advances in statistical mechanics and relies on a message passing procedure. The second follows a more standard Monte Carlo Markov chain strategy. Special attention is devoted to Hamiltonian cycles of (nonregular) random graphs of minimal connectivity equal to 3.

  10. Ecology of the nitrogen cycle

    SciTech Connect

    Sprent, J.J.

    1987-01-01

    This book consists of two parts, approximately equal in size. The first part covers the general features of the nitrogen cycle, while the second part consists of case histories from particular environments. These include arid and semi-arid areas, tundras, peat soils, lakes, marshes, and such saline systems as salt marshes, coral reefs, intertidal zones, and the open sea. The last chapter discusses the human impact on the cycle through agriculture, forestry, and acidification.

  11. The Arabidopsis Cell Division Cycle

    PubMed Central

    Gutierrez, Crisanto

    2009-01-01

    Plant cells have evolved a complex circuitry to regulate cell division. In many aspects, the plant cell cycle follows a basic strategy similar to other eukaryotes. However, several key issues are unique to plant cells. In this chapter, both the conserved and unique cellular and molecular properties of the plant cell cycle are reviewed. In addition to division of individual cells, the specific characteristic of plant organogenesis and development make that cell proliferation control is of primary importance during development. Therefore, special attention should be given to consider plant cell division control in a developmental context. Proper organogenesis depends on the formation of different cell types. In plants, many of the processes leading to cell differentiation rely on the occurrence of a different cycle, termed the endoreplication cycle, whereby cells undergo repeated full genome duplication events in the absence of mitosis and increase their ploidy. Recent findings are focusing on the relevance of changes in chromatin organization for a correct cell cycle progression and, conversely, in the relevance of a correct functioning of chromatin remodelling complexes to prevent alterations in both the cell cycle and the endocycle. PMID:22303246

  12. Solar Cycle Predictions (Invited Review)

    NASA Astrophysics Data System (ADS)

    Pesnell, W. Dean

    2012-11-01

    Solar cycle predictions are needed to plan long-term space missions, just as weather predictions are needed to plan the launch. Fleets of satellites circle the Earth collecting many types of science data, protecting astronauts, and relaying information. All of these satellites are sensitive at some level to solar cycle effects. Predictions of drag on low-Earth orbit spacecraft are one of the most important. Launching a satellite with less propellant can mean a higher orbit, but unanticipated solar activity and increased drag can make that a Pyrrhic victory as the reduced propellant load is consumed more rapidly. Energetic events at the Sun can produce crippling radiation storms that endanger all assets in space. Solar cycle predictions also anticipate the shortwave emissions that cause degradation of solar panels. Testing solar dynamo theories by quantitative predictions of what will happen in 5 - 20 years is the next arena for solar cycle predictions. A summary and analysis of 75 predictions of the amplitude of the upcoming Solar Cycle 24 is presented. The current state of solar cycle predictions and some anticipations of how those predictions could be made more accurate in the future are discussed.

  13. Cycling operation of fossil plants

    SciTech Connect

    Devendorf, D.; Kulczycky, T.G. )

    1991-05-01

    A necessity for many utilities today is the cycling of their fossil units. Fossil plants with their higher fuel costs are being converted to cycling operation to accommodate daily load swings and to decrease the overall system fuel costs. For a large oil-fired unit, such as Oswego Steam Station Unit 5, millions of dollars can be saved annually in fuel costs if the unit operates in a two-shift mode. However, there are also penalties attributable to cycling operation which are associated with availability and thermal performance. The objectives of Niagara Mohawk Power Corporation were to minimize the losses in availability and performance, and the degradation in the life of the equipment by incorporating certain cycling modifications into the unit. The objective of this project was to evaluate the effectiveness of three of these cycling modifications: (1) the superheater and turbine bypass (Hot Restart System), (2) the use of variable pressure operation, and (3) the full-flow condensate polishing system. To meet this objective, Unit 5 was tested using the cycling modifications, and a dynamic mathematical model of this unit was developed using the Modular Modeling System (MMS) Code from EPRI. This model was used to evaluate various operating modes and to assist in the assessment of operating procedures. 15 refs., 41 figs., 22 tabs.

  14. The NEWS Water Cycle Climatology

    NASA Technical Reports Server (NTRS)

    Rodell, Matthew; Beaudoing, Hiroko Kato; L'Ecuyer, Tristan; William, Olson

    2012-01-01

    NASA's Energy and Water Cycle Study (NEWS) program fosters collaborative research towards improved quantification and prediction of water and energy cycle consequences of climate change. In order to measure change, it is first necessary to describe current conditions. The goal of the first phase of the NEWS Water and Energy Cycle Climatology project was to develop "state of the global water cycle" and "state of the global energy cycle" assessments based on data from modern ground and space based observing systems and data integrating models. The project was a multi-institutional collaboration with more than 20 active contributors. This presentation will describe the results of the water cycle component of the first phase of the project, which include seasonal (monthly) climatologies of water fluxes over land, ocean, and atmosphere at continental and ocean basin scales. The requirement of closure of the water budget (i.e., mass conservation) at various scales was exploited to constrain the flux estimates via an optimization approach that will also be described. Further, error assessments were included with the input datasets, and we examine these in relation to inferred uncertainty in the optimized flux estimates in order to gauge our current ability to close the water budget within an expected uncertainty range.

  15. Thermodynamic Cycles--One More Time.

    ERIC Educational Resources Information Center

    Nolan, Michael J.

    1995-01-01

    Discusses interesting aspects of the Carnot cycle and other thermodynamic cycles that are generally not dealt with in elementary physics texts. Presents examples that challenge the student to think about the extraction of net work from a cycle. (JRH)

  16. The Sphinx's Riddle: Life and Career Cycles.

    ERIC Educational Resources Information Center

    Burack, Elmer H.

    1984-01-01

    Career cycles should be considered apart from life cycles, even though the two are interrelated. This essay examines five theories about life and career cycles, and offers insights into their limitations and potential uses. (JB)

  17. Enhanced absorption cycle computer model

    NASA Astrophysics Data System (ADS)

    Grossman, G.; Wilk, M.

    1993-09-01

    Absorption heat pumps have received renewed and increasing attention in the past two decades. The rising cost of electricity has made the particular features of this heat-powered cycle attractive for both residential and industrial applications. Solar-powered absorption chillers, gas-fired domestic heat pumps, and waste-heat-powered industrial temperature boosters are a few of the applications recently subjected to intensive research and development. The absorption heat pump research community has begun to search for both advanced cycles in various multistage configurations and new working fluid combinations with potential for enhanced performance and reliability. The development of working absorption systems has created a need for reliable and effective system simulations. A computer code has been developed for simulation of absorption systems at steady state in a flexible and modular form, making it possible to investigate various cycle configurations with different working fluids. The code is based on unit subroutines containing the governing equations for the system's components and property subroutines containing thermodynamic properties of the working fluids. The user conveys to the computer an image of his cycle by specifying the different subunits and their interconnections. Based on this information, the program calculates the temperature, flow rate, concentration, pressure, and vapor fraction at each state point in the system, and the heat duty at each unit, from which the coefficient of performance (COP) may be determined. This report describes the code and its operation, including improvements introduced into the present version. Simulation results are described for LiBr-H2O triple-effect cycles, LiCl-H2O solar-powered open absorption cycles, and NH3-H2O single-effect and generator-absorber heat exchange cycles. An appendix contains the user's manual.

  18. Final Report - The Xanthophyll Cycle

    SciTech Connect

    Harry Yamamato

    2005-04-21

    The xanthophyll cycle is a ubiquitous activity in higher plants. A major function of the cycle is to protect the photosynthetic system from the potentially damaging effects of high light by dissipating excess energy that might otherwise damage the photosynthetic apparatus harmlessly as heat by a process termed non-photochemical quenching (NFQ). This research focused on investigating the dynamics of the relationship between PsbS, subunit PSII protein required for NPQ, and zeaxanthin by perturbing the natural relationship of these components by overexpression of PsbS, violaxanthin de-epoxidase (VDE), and PsbS-VDE in tobacco. The effects of these treatments showed that the relationship between NPQ and zeaxanthin formation is more complex than previously indicated from studies carried out under high light. It is postulated that the xanthophyll cycle functions as a type of signal-transduction system within the thylakoid membrane. Recent studies in model lipid systems demonstrated that zeaxanthin exerts feedback inhibition on violaxanthin de-epoxidase. This feedback inhibition is consistent with the lipid phase functioning as a modulating factor in the dynamics of the cycle's operation. While this research and those in other laboratories have defined both the biochemistry and molecular mechanism of the cycle's operation, especially for violaxanthin de-epoxidase, there is yet insufficient knowledge that explains the ubiquitous presence of the cycle in all higher plants and a related cycle in diatoms. Antisense VDE tobacco plants (work carried out under another grant) withstood the high-light environment in Hawaii over one generation. Thus, it is speculated that the protective system was essential for survival in earth's high-light earth environment over multiple generations. The proposed signal transduction protective system, however, may explain the ability of the protective system to modulate or adapt to a range of environments.

  19. Myc and cell cycle control.

    PubMed

    Bretones, Gabriel; Delgado, M Dolores; León, Javier

    2015-05-01

    Soon after the discovery of the Myc gene (c-Myc), it became clear that Myc expression levels tightly correlate to cell proliferation. The entry in cell cycle of quiescent cells upon Myc enforced expression has been described in many models. Also, the downregulation or inactivation of Myc results in the impairment of cell cycle progression. Given the frequent deregulation of Myc oncogene in human cancer it is important to dissect out the mechanisms underlying the role of Myc on cell cycle control. Several parallel mechanisms account for Myc-mediated stimulation of the cell cycle. First, most of the critical positive cell cycle regulators are encoded by genes induced by Myc. These Myc target genes include Cdks, cyclins and E2F transcription factors. Apart from its direct effects on the transcription, Myc is able to hyperactivate cyclin/Cdk complexes through the induction of Cdk activating kinase (CAK) and Cdc25 phosphatases. Moreover, Myc antagonizes the activity of cell cycle inhibitors as p21 and p27 through different mechanisms. Thus, Myc is able to block p21 transcription or to induce Skp2, a protein involved in p27 degradation. Finally, Myc induces DNA replication by binding to replication origins and by upregulating genes encoding proteins required for replication initiation. Myc also regulates genes involved in the mitotic control. A promising approach to treat tumors with deregulated Myc is the synthetic lethality based on the inhibition of Cdks. Thus, the knowledge of the Myc-dependent cell cycle regulatory mechanisms will help to discover new therapeutic approaches directed against malignancies with deregulated Myc. This article is part of a Special Issue entitled: Myc proteins in cell biology and pathology. PMID:24704206

  20. A comparative look at sunspot cycles

    NASA Technical Reports Server (NTRS)

    Wilson, R. M.

    1984-01-01

    On the basis of cycles 8 through 20, spanning about 143 years, observations of sunspot number, smoothed sunspot number, and their temporal properties were used to compute means, standard deviations, ranges, and frequency of occurrence histograms for a number of sunspot cycle parameters. The resultant schematic sunspot cycle was contrasted with the mean sunspot cycle, obtained by averaging smoothed sunspot number as a function of time, tying all cycles (8 through 20) to their minimum occurence date. A relatively good approximation of the time variation of smoothed sunspot number for a given cycle is possible if sunspot cycles are regarded in terms of being either HIGH- or LOW-R(MAX) cycles or LONG- or SHORT-PERIOD cycles, especially the latter. Linear regression analyses were performed comparing late cycle parameters with early cycle parameters and solar cycle number. The early occurring cycle parameters can be used to estimate later occurring cycle parameters with relatively good success, based on cycle 21 as an example. The sunspot cycle record clearly shows that the trend for both R(MIN) and R(MAX) was toward decreasing value between cycles 8 through 14 and toward increasing value between cycles 14 through 20. Linear regression equations were also obtained for several measures of solar activity.

  1. The Manuel Lujan, Jr. Neutron Scattering Center (LANSCE) experiment reports 1992 run cycle. Progress report

    SciTech Connect

    DiStravolo, M.A.

    1993-09-01

    This year was the fifth in which LANSCE ran a formal user program. A call for proposals was issued before the scheduled run cycles, and experiment proposals were submitted by scientists from universities, industry, and other research facilities around the world. An external program advisory committee, which LANSCE shares with the Intense Pulsed Neutron Source (IPNS), Argonne National Laboratory, examined the proposals and made recommendations. At LANSCE, neutrons are produced by spallation when a pulsed, 800-MeV proton beam impinges on a tungsten target. The proton pulses are provided by the Clinton P. Anderson Meson Physics Facility (LAMPF) accelerator and an associated Proton Storage Ring (PSR), which can alter the intensity, time structure, and repetition rate of the pulses. The LAMPF protons of Line D are shared between the LANSCE target and the Weapons Neutron Research (WNR) facility, which results in LANSCE spectrometers being available to external users for unclassified research about 80% of each annual LAMPF run cycle. Measurements of interest to the Los Alamos National Laboratory may also be performed and may occupy up to an additional 20% of the available beam time. These experiments are reviewed by an internal program advisory committee. One hundred sixty-seven proposals were submitted for unclassified research and twelve proposals for research of a programmatic interest to the Laboratory; six experiments in support of the LANSCE research program were accomplished during the discretionary periods. Oversubscription for instrument beam time by a factor of three was evident with 839 total days requested and only 371 available for allocation.

  2. The Manuel Lujan, Jr. Neutron Scattering Center, LANSCE experiment reports: 1990 Run Cycle

    SciTech Connect

    DiStravolo, M.A.

    1991-10-01

    This year was the third in which LANSCE ran a formal user program. A call for proposals was issued before the scheduled run cycles, and experiment proposals were submitted by scientists from universities, industry, and other research facilities around the world. An external program advisory committee, which LANSCE shares with the Intense Pulsed Neutron Source (IPNS), Argonne National Laboratory examined the proposals and made recommendations. At LANSCE, neutrons are produced by spallation when a pulsed, 800-MeV proton beam impinges on a tungsten target. The proton pulses are provided by the Clinton P. Anderson Meson Physics Facility (LAMPF) accelerator and an associated Proton Storage Ring (PSR), which can alter the intensity, time structure, and repetition rate of the pulses. The LAMPF protons of Line D are shared between the LANSCE target and the Weapons Neutron Research facility, which results in LANSCE spectrometers being available to external users for unclassified research about 80% of each six-month LAMPF run cycle. Measurements of interest to the Los Alamos National Laboratory may also be performed and may occupy up to an additional 20% of the available beam time. These experiments are reviewed by an internal program advisory committee. One hundred thirty-four proposals were submitted for unclassified research and twelve proposals for research of a programmatic nature to the Laboratory. Our definition of beam availability is when the proton current from the PSR exceeds 50% of the planned value. The PSR ran at 65{mu}A current (average) at 20 Hz for most of 1990. All of the scheduled experiments were performed and experiments in support of the LANSCE research program were accomplished during the discretionary periods.

  3. The chromosome cycle of prokaryotes

    PubMed Central

    Kuzminov, Andrei

    2013-01-01

    Summary In both eukaryotes and prokaryotes, chromosomal DNA undergoes replication, condensation-decondensation and segregation, sequentially, in some fixed order. Other conditions, like sister-chromatid cohesion (SCC), may span several chromosomal events. One set of these chromosomal transactions within a single cell cycle constitutes the “chromosome cycle”. For many years it was generally assumed that the prokaryotic chromosome cycle follows major phases of the eukaryotic one: -replication-condensation-segregation-(cell division)-decondensation-, with SCC of unspecified length. Eventually it became evident that, in contrast to the strictly consecutive chromosome cycle of eukaryotes, all stages of the prokaryotic chromosome cycle run concurrently. Thus, prokaryotes practice “progressive” chromosome segregation separated from replication by a brief SCC, and all three transactions move along the chromosome at the same fast rate. In other words, in addition to replication forks, there are “segregation forks” in prokaryotic chromosomes. Moreover, the bulk of prokaryotic DNA outside the replication-segregation transition stays compacted. I consider possible origins of this concurrent replication-segregation and outline the “nucleoid administration” system that organizes the dynamic part of the prokaryotic chromosome cycle. PMID:23962352

  4. Answering Key Fuel Cycle Questions

    SciTech Connect

    Piet, S.J.; Dixon, B.W.; Bennett, R.G.; Smith, J.D.; Hill, R.N.

    2004-10-03

    Given the range of fuel cycle goals and criteria, and the wide range of fuel cycle options, how can the set of options eventually be narrowed in a transparent and justifiable fashion? It is impractical to develop all options. We suggest an approach that starts by considering a range of goals for the Advanced Fuel Cycle Initiative (AFCI) and then posits seven questions, such as whether Cs and Sr isotopes should be separated from spent fuel and, if so, what should be done with them. For each question, we consider which of the goals may be relevant to eventually providing answers. The AFCI program has both ''outcome'' and ''process'' goals because it must address both waste already accumulating as well as completing the fuel cycle in connection with advanced nuclear power plant concepts. The outcome objectives are waste geologic repository capacity and cost, energy security and sustainability, proliferation resistance, fuel cycle economics, and safety. The process objectives are rea diness to proceed and adaptability and robustness in the face of uncertainties.

  5. ALMA Cycle 0 Publication Statistics

    NASA Astrophysics Data System (ADS)

    Stoehr, F.; Grothkopf, U.; Meakins, S.; Bishop, M.; Uchida, A.; Testi, L.; Iono, D.; Tatematsu, K.; Wootten, A.

    2015-12-01

    The scientific impact of a facility is the most important measure of its success. Monitoring and analysing the scientific return can help to modify and optimise operations and adapt to the changing needs of scientific research. The methodology that we have developed to monitor the scientific productivity of the ALMA Observatory, as well as the first results, are described. We focus on the outcome of the first cycle (Cycle 0) of ALMA Early Science operations. Despite the fact that only two years have passed since the completion of Cycle 0 and operations have already changed substantially, this analysis confirms the effectiveness of the underlying concepts. We find that ALMA is fulfilling its promise as a transformational facility for the observation of the Universe in the submillimetre.

  6. Optimization of data life cycles

    NASA Astrophysics Data System (ADS)

    Jung, C.; Gasthuber, M.; Giesler, A.; Hardt, M.; Meyer, J.; Rigoll, F.; Schwarz, K.; Stotzka, R.; Streit, A.

    2014-06-01

    Data play a central role in most fields of science. In recent years, the amount of data from experiment, observation, and simulation has increased rapidly and data complexity has grown. Also, communities and shared storage have become geographically more distributed. Therefore, methods and techniques applied to scientific data need to be revised and partially be replaced, while keeping the community-specific needs in focus. The German Helmholtz Association project "Large Scale Data Management and Analysis" (LSDMA) aims to maximize the efficiency of data life cycles in different research areas, ranging from high energy physics to systems biology. In its five Data Life Cycle Labs (DLCLs), data experts closely collaborate with the communities in joint research and development to optimize the respective data life cycle. In addition, the Data Services Integration Team (DSIT) provides data analysis tools and services which are common to several DLCLs. This paper describes the various activities within LSDMA and focuses on the work performed in the DLCLs.

  7. The cell cycle and pluripotency.

    PubMed

    Hindley, Christopher; Philpott, Anna

    2013-04-15

    PSCs (pluripotent stem cells) possess two key properties that have made them the focus of global research efforts in regenerative medicine: they have unlimited expansion potential under conditions which favour their preservation as PSCs and they have the ability to generate all somatic cell types upon differentiation (pluripotency). Conditions have been defined in vitro in which pluripotency is maintained, or else differentiation is favoured and is directed towards specific somatic cell types. However, an unanswered question is whether or not the core cell cycle machinery directly regulates the pluripotency and differentiation properties of PSCs. If so, then manipulation of the cell cycle may represent an additional tool by which in vitro maintenance or differentiation of PSCs may be controlled in regenerative medicine. The present review aims to summarize our current understanding of links between the core cell cycle machinery and the maintenance of pluripotency in ESCs (embryonic stem cells) and iPSCs (induced PSCs). PMID:23535166

  8. Cell Cycle Regulation and Melanoma.

    PubMed

    Xu, Wen; McArthur, Grant

    2016-06-01

    Dysregulation of cell cycle control is a hallmark of melanomagenesis. Agents targeting the G1-S and G2-M checkpoints, as well as direct anti-mitotic agents, have all shown promising preclinical activity in melanoma. However, in vivo, standalone single agents targeting cell cycle regulation have only demonstrated modest efficacy in unselected patients. The advent of specific CDK 4/6 inhibitors targeting the G1-S transition, with an improved therapeutic index, is a significant step forward. Potential synergy exists with the combination of CDK4/6 inhibitors with existing therapies targeting the MAPK pathway, particularly in subsets of metastatic melanomas such as NRAS and BRAF mutants. This reviews summaries of the latest developments in both preclinical and clinical data with cell cycle-targeted therapies in melanoma. PMID:27106898

  9. SIRTF Cycle-1 Research Opportunities

    NASA Astrophysics Data System (ADS)

    Soifer, B. T.; Bicay, M. D.

    2003-12-01

    The Space InfraRed Telescope Facility (SIRTF), the fourth and final element in NASA's family of Great Observatories, was successfully launched into an Earth-trailing heliocentric orbit on August 25, 2003. The SIRTF Science Center (SSC) at Caltech is now soliciting Cycle-1 research proposals from the worldwide scientific community. Proposals must be submitted electronically to the SSC by February 14, 2004. A preliminary version of the Cycle-1 Call for Proposals (CP) was issued by the SSC in November 2002. A CP Update and supporting technical documentation, which incorporates the on-orbit performance of the observatory, were released in December 2003. Investigations may be proposed for new SIRTF observations, through the General Observer (GO) program, or for archival research. About 3700 hours of observing time is being offered for the Cycle-1 GO Program, in small (less than 50 hours) and medium (50 to 200 hours) categories. More than \\15 million in NASA data analysis support is available to qualified GO investigators. For GO proposals, a detailed list of proposed observations, generated by the SIRTF Planning Observations Tool, must accompany the research proposal. The Archival Research (AR) Program in Cycle-1 is limited to the analysis of data from the First-Look Survey, a 100-hour program to be executed by the SSC at the start of the science mission. Up to \\750,000 in NASA data analysis support is available to qualified AR investigators. All documents supporting the Cycle-1 solicitation are available online in the Proposal Kit section of the SSC public Web site (http://sirtf.caltech.edu/SSC/). Questions pertaining to the Cycle-1 CP should be sent electronically to the SSC HelpDesk at sirtf@ipac.caltech.edu. SIRTF is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA.

  10. SNMR pulse sequence phase cycling

    DOEpatents

    Walsh, David O; Grunewald, Elliot D

    2013-11-12

    Technologies applicable to SNMR pulse sequence phase cycling are disclosed, including SNMR acquisition apparatus and methods, SNMR processing apparatus and methods, and combinations thereof. SNMR acquisition may include transmitting two or more SNMR pulse sequences and applying a phase shift to a pulse in at least one of the pulse sequences, according to any of a variety cycling techniques. SNMR processing may include combining SNMR from a plurality of pulse sequences comprising pulses of different phases, so that desired signals are preserved and indesired signals are canceled.

  11. Cell Cycle Regulation by Checkpoints

    PubMed Central

    Barnum, Kevin J.; O’Connell, Matthew J.

    2016-01-01

    Cell cycle checkpoints are surveillance mechanisms that monitor the order, integrity, and fidelity of the major events of the cell cycle. These include growth to the appropriate cell size, the replication and integrity of the chromosomes, and their accurate segregation at mitosis. Many of these mechanisms are ancient in origin and highly conserved, and hence have been heavily informed by studies in simple organisms such as the yeasts. Others have evolved in higher organisms, and control alternative cell fates with significant impact on tumor suppression. Here, we consider these different checkpoint pathways and the consequences of their dysfunction on cell fate. PMID:24906307

  12. Biogeochemical cycling and remote sensing

    NASA Technical Reports Server (NTRS)

    Peterson, D. L.

    1985-01-01

    Research is underway at the NASA Ames Research Center that is concerned with aspects of the nitrogen cycle in terrestrial ecosystems. An interdisciplinary research group is attempting to correlate nitrogen transformations, processes, and productivity with variables that can be remotely sensed. Recent NASA and other publications concerning biogeochemical cycling at global scales identify attributes of vegetation that could be related or explain the spatial variation in biologically functional variables. These functional variables include net primary productivity, annual nitrogen mineralization, and possibly the emission rate of nitrous oxide from soils.

  13. Simple ocean carbon cycle models

    SciTech Connect

    Caldeira, K.; Hoffert, M.I.; Siegenthaler, U.

    1994-02-01

    Simple ocean carbon cycle models can be used to calculate the rate at which the oceans are likely to absorb CO{sub 2} from the atmosphere. For problems involving steady-state ocean circulation, well calibrated ocean models produce results that are very similar to results obtained using general circulation models. Hence, simple ocean carbon cycle models may be appropriate for use in studies in which the time or expense of running large scale general circulation models would be prohibitive. Simple ocean models have the advantage of being based on a small number of explicit assumptions. The simplicity of these ocean models facilitates the understanding of model results.

  14. Carbon Cycling in Northern Peatlands

    NASA Astrophysics Data System (ADS)

    Schultz, Colin

    2010-11-01

    Northern peatlands span only 3 million square kilometers, about 3% of the terrestrial area of the globe, yet they represent a significant terrestrial sink for carbon dioxide. They are also important emitters of methane, an even more potent greenhouse gas. Despite their substantial role in the global carbon cycle, peatlands are not typically incorporated into global climate models. The AGU Monograph Carbon Cycling in Northern Peatlands, edited by Andrew J. Baird, Lisa R. Belyea, Xavier Comas, A. S. Reeve, and Lee D. Slater, looks at the disproportionate role peatlands play in the global carbon budget. In this interview, Eos talks with Andy Baird, University of Leeds, Leeds, United Kingdom.

  15. Properties of stellar activity cycles

    NASA Astrophysics Data System (ADS)

    Korhonen, Heidi

    2015-08-01

    The current photometric datasets, that span decades, allow for studying long-term magentic cycles on active stars. Complementary Ca H&K observations give information also on the cycles of normal solar-like stars, which have significantly smaller, and less easily detectable, spots. In recent years, high precision space-based observations, for example from the Kepler satellite, have allowed also to study the sunspot-like spot sizes in other stars. In this talk I will review what is known about the properties of the cyclic stellar activity in other stars than our Sun, and also discuss the future prospects in this field.

  16. Advanced Nuclear Fuel Cycle Options

    SciTech Connect

    Roald Wigeland; Temitope Taiwo; Michael Todosow; William Halsey; Jess Gehin

    2010-06-01

    A systematic evaluation has been conducted of the potential for advanced nuclear fuel cycle strategies and options to address the issues ascribed to the use of nuclear power. Issues included nuclear waste management, proliferation risk, safety, security, economics and affordability, and sustainability. The two basic strategies, once-through and recycle, and the range of possibilities within each strategy, are considered for all aspects of the fuel cycle including options for nuclear material irradiation, separations if needed, and disposal. Options range from incremental changes to today’s implementation to revolutionary concepts that would require the development of advanced nuclear technologies.

  17. GAX absorption cycle design process

    SciTech Connect

    Priedeman, D.K.; Christensen, R.N.

    1999-07-01

    This paper presents an absorption system design process that relies on computer simulations that are validated by experimental findings. An ammonia-water absorption heat pump cycle at 3 refrigeration tons (RT) and chillers at 3.3 RT and 5 RT (10.5 kW, 11.6 kW, and 17.6 kW) were initially modeled and then built and tested. The experimental results were used to calibrate both the cycle simulation and the component simulations, yielding computer design routines that could accurately predict component and cycle performance. Each system was a generator-absorber heat exchange (GAX) cycle, and all were sized for residential and light commercial use, where very little absorption equipment is currently used. The specific findings of the 5 RT (17.6 kW) chiller are presented. Modeling incorporated a heat loss from the gas-fired generator and pressure drops in both the evaporator and absorber. Simulation results and experimental findings agreed closely and validated the modeling method and simulation software.

  18. Seasonal Nitrogen Cycles on Pluto

    NASA Technical Reports Server (NTRS)

    Hansen, C. J.; Paige, D. A.

    1994-01-01

    A thermal model, developed to predict seasonal nitrogen cycles on Triton, has been modified and applied to Pluto. The model is used to calculate the partitioning of nitrogen between surface frost deposits and the atmosphere, as a function of time for various sets of input parameters.

  19. PRODUCTION CYCLES IN AQUATIC MICROCOSMS

    EPA Science Inventory

    Four 700-liter cylindrical containers were filled with demineralized water, enriched with nutrients, and inoculated with 3.5-liter lakewater samples. The microcosms were maintained at a temperature of 18C under a 12:12 L:D cycle for 6 months and several manipulations of their tro...

  20. Menopause: A Life Cycle Transition.

    ERIC Educational Resources Information Center

    Evarts, Barbara Kess; Baldwin, Cynthia

    1998-01-01

    Family therapists need to address the issue of menopause proactively to be of benefit to couples and families during this transitional period in the family life cycle. Physical, psychological, and psychosocial factors affecting the menopausal woman and her family, and ways to address these issues in counseling are discussed. (Author/EMK)