pinecone/core-2020-05-10-deduplication huggingface dataset:
The adventures of Spacetime

We discuss how developments in physics often imply in the need that spacetime
acquires an increasingly richer and complex structure. General Relativity was
the first theory to show us the way to connect space and time with the physical
world. Since then, scrutinizing the ways spacetime might exist is, in a way,
the very essence of physics. Physics has thus given substance to the pioneering
work of scores of brilliant mathematicians who speculated on the geometry and
topology of spaces.Comment: Chapter in the book Relativity and the Dimensionality of the World to
  be published in the Springer series Fundamental Theories of Physics. Volume
  Editor: Vesselin Petkov. 18 pages plus macros; updated reference
Numerical solution of the Holstein polaron problem

We performed an extensive numerical analysis of the Holstein model. Combining
variational Lanczos diagonalisation, density matrix renormalisation group,
kernel polynomial expansion, and cluster perturbation theory techniques we
solved for properties of the Holstein polaron and bipolaron problems. Numerical
solution of the Holstein model means that we determined the ground-state and
low-lying excited states with arbitrary precision in the thermodynamic limit
for any dimension. Moreover, we calculated the spectral properties (e.g.
photoemission and phonon spectra), optical response and thermal transport, as
well as the dynamics of polaron formation. Our approach takes into account the
full quantum dynamics of the electrons and phonons and yields unbiased results
for all electron-phonon interaction strengths and phonon frequencies, but is of
particular value in the intermediate-coupling regime, where perturbation
theories and other analytical techniques fail.Comment: 69 pages, 36 figures, revised version to be published in Polarons in
  Advanced Materials, Ed. A. S. Alexandrov (Canopus/Springer Publishing,
  Bristol) (2007
Lang-Firsov approaches to polaron physics: From variational methods to
  unbiased quantum Monte Carlo simulations

We review variational and quantum Monte Carlo approaches based on (extended)
Lang-Firsov transformations of the Hamiltonian. Derivations for one, two and
many electrons are given, and results for the Holstein polaron, the
Holstein-Hubbard bipolaron, and the spinless Holstein model at finite carrier
densities are presented.Comment: 40 pages, 15 figures, to be published in Polarons in Advanced
  Materials, Ed. A. S. Alexandrov (Canopus/Springer Publishing, Bristol)
  (2007); V2: typo in authors list correcte
Spectroscopic Properties of Polarons in Strongly Correlated Systems by
  Exact Diagrammatic Monte Carlo Method

We present recent advances in understanding of the ground and excited states
of the electron-phonon coupled systems obtained by novel methods of
Diagrammatic Monte Carlo and Stochastic Optimization, which enable the
approximation-free calculation of Matsubara Green function in imaginary times
and perform unbiased analytic continuation to real frequencies. We present
exact numeric results on the ground state properties, Lehmann spectral function
and optical conductivity of different strongly correlated systems: Frohlich
polaron, Rashba-Pekar exciton-polaron, pseudo Jahn-Teller polaron, exciton, and
interacting with phonons hole in the t-J model.Comment: 41 pages, 13 figures, in "Polarons in Advanced Materials" ed. A. S.
  Alexandrov (Canopus/Springer Publishing, Bristol (2007)), pp. 503-544
Current rectification, switching, polarons, and defects in molecular
  electronic devices

Devices for nano- and molecular size electronics are currently a focus of
research aimed at an efficient current rectification and switching. A few
generic molecular scale devices are reviewed here on the basis of
first-principles and model approaches. Current rectification by (ballistic)
molecular quantum dots can produce the rectification ratio ~100. Current
switching due to conformational changes in the molecules is slow, on the order
of a few kHz. Fast switching (~1THz) may be achieved, at least in principle, in
a degenerate molecular quantum dot with strong coupling of electrons with
vibrational excitations. We show that the mean-field approach fails to properly
describe intrinsic molecular switching and present an exact solution to the
problem. Defects in molecular films result in spurious peaks in conductance,
apparent negative differential resistance, and may also lead to unusual
temperature and bias dependence of current. The observed switching in many
cases is_extrinsic_, caused by changes in molecule-electrode geometry, molecule
reconfiguration, metallic filament formation through, and/or changing amount of
disorder in a molecular film. We give experimental examples of telegraph
"switching" and "hot spot" formation in the molecular films.Comment: 43 pages, 16 figures, invited talk at Mott Physics symposium
  (Cambridge, 2006), to be published in Polarons in Advanced Materials, edited
  by A. S. Alexandrov (Canopus/Springer, Bristol, 2007
Path integrals in the physics of lattice polarons

A path-integral approach to lattice polarons is developed. The method is
based on exact analytical elimination of phonons and subsequent Monte Carlo
simulation of self-interacting fermions. The analytical basis of the method is
presented with emphasis on visualization of polaron effects, which path
integrals provide. Numerical results on the polaron energy, mass, spectrum and
density of states are given for short-range and long-range electron-phonon
interactions. It is shown that certain long-range interactions significantly
reduce the polaron mass, and anisotropic interactions enhance polaron
anisotropy. The isotope effect on the polaron mass and spectrum is discussed. A
path-integral approach to the Jahn-Teller polaron is developed. Extensions of
the method to lattice bipolarons and to more complex polaron models are
outlined.Comment: 40 pages, 12 figures, to be published in "Polarons in Advanced
  Materials" ed. A.S. Alexandrov (Canopus Books, 2007
Path Integral Methods in the Su-Schrieffer-Heeger Polaron Problem

I propose a path integral description of the Su-Schrieffer-Heeger
Hamiltonian, both in one and two dimensions, after mapping the real space model
onto the time scale. While the lattice degrees of freedom are classical
functions of time and are integrated out exactly, the electron particle paths
are treated quantum mechanically. The method accounts for the variable range of
the electronic hopping processes. The free energy of the system and its
temperature derivatives are computed by summing at any $T$ over the ensemble of
relevant particle paths which mainly contribute to the total partition
function. In the low $T$ regime, the {\it heat capacity over T} ratio shows un
upturn peculiar to a glass-like behavior. This feature is more sizeable in the
square lattice than in the linear chain as the overall hopping potential
contribution to the total action is larger in higher dimensionality. The
effects of the electron-phonon anharmonic interactions on the phonon subsystem
are studied by the path integral cumulant expansion method.Comment: to appear in "Polarons in Advanced Materials" ed. A.S. Alexandrov
  (Canopus Books, 2007
Protocol for micropropagation of Castanea sativa Mill.

Final version of the chapter at: http://dx.doi.org/10.1007/978-1-4020-6352-7_28.Since the 1970s, natural resources the world over have been progressively re-evaluated in accordance with the principles of sustainable agriculture. The European chestnut, Castanea sativa Mill., a hardwood species belonging to the family Fagaceae, has not been unaffected by this process. It is an important resource in many parts of the world because of its economic and environmental role in many agroforestry systems, and in Europe it has been gaining in value as a source of timber and nut production and due to the contribution of chestnut groves to the landscape (Bounous, 2005).Like the American chestnut C. dentata, C. sativa has been plagued for more than a century by ink disease and chestnut blight, caused by the fungi Phytophthora cinnamomi and Cryphonectria parasitica, respectively. A great deal of research on chestnut focuses on the development of vegetative propagation systems capable of satisfying the demand for elite genotypes that provide both high-quality timber and/or nuts and resistance to these diseases. Since chestnut is a difficult-to-root species, grafting is the most frequent conventional propagation technique, although methods for layering and cutting have recently been improved and are widely used in nurseries to propagate ink-disease-resistant Euro-Japanese hybrids. However, as an alternative to conventional vegetative propagation methods, efforts are being made to establish reliable in vitro regeneration systems that allow clonal propagation. The two major systems are based on embryogenesis or on micropropagation of axillary shoots.Thanks are given to Spanish Ministry of Education and Science (project AGL2005-00709) and Xunta de Galicia, Spain (project PGIDIT03RFO40001PR) for financial support.Peer reviewe
Revisiting the traditional virtues of the hero : a phenomenological study of Wilfred Owen’s disabled soldier

Thanks to critics like Roman Ingarden and Wolfgang Iser, we treat the literary object as a phenomenon actualized and then maintained in being through the reader’s effort in realizing the poem, that is, only through irony, paradox, metaphor, metonymy, and other aesthetic techniques that perform the text as a portrayed world. Real external entities, such as a disabled war victim, attain to a poetic existence, such as Wilfred Owen’s mutilated soldier in the poem “Disabled,” by virtue of this aesthetic effort, fulfilled each time literary comprehension is felt to have reached beyond a previous inadequate degree of realization.peer-reviewe
Development of Direct Democracy in Swiss Cantons between 1997 and 2003

This paper describes institutions of direct democracy between 1997 and 2003 in 26 Swiss cantons (states), specifically the statutory initiative and referendum, the constitutional initiative, and the fiscal referendum. In particular, it discusses their applications, but also the legal requirements for making use of them, including the signature requirements, the time available for their collection, and the financial thresholds. Optional and mandatory forms of these direct-legislative institutions are distinguished. 
This paper also provides calculations of the index and sub-indices of direct democracy for the additional years 1997 to 2003, in continuation of Stutzer (1999), using the identical methodology. Extending Trechsel and Serdült (1999) and Stutzer (1999) this paper includes the political institutions of the so-called Landsgemeinde cantons. Description of these institutions is based on the author’s reading of 26 cantonal constitutions in their versions between 1997 and 2003.
Hygroscopic and Volatile Properties of Ultrafine Particles in the Eucalypt Forests: Comparison with Chamber Experiments and the Role of Sulphates in New Particle Formation

Simultaneous measurements of the volatile and hygroscopic properties of ultrafine particles were conducted in a Eucalypt forest in Tumbarumba, South-East Australia, in November 2006. These measurements were part of an intensive field campaign EUCAP 2006 (Eucalypt Forest Aerosols and Precursors). The particles exhibited a 2 step volatilisation with the first component starting to evaporate at temperatures above 50 degrees Celsius. With the onset of evaporation of the first component the hygroscopic growth factor increased. This indicated that the particle was composed of a less volatile, but more hygroscopic core, which was coated with a more volatile, but less hygroscopic, coating. The fraction of the more hygroscopic component was proportional to the measured maximum SO2 concentration indicating the role of gaseous H2SO4 in new particle formation. As the volatilisation temperature of the second more hygroscopic component was above that for H2SO4 it is likely that this component is partially or fully neutralised H2SO4. Comparison with pinene smog chamber experiments shows an excellent agreement with the first step volatilisation indicating its origin in the photooxidation of a monoterpene precursor
Atmospheric aerosol and ion characteristics during EUCAP (Eucalypt Forest Aerosols and Precursors)

We measured the characteristics and dynamics of atmospheric ions, aerosol particles, and their precursors in an intensive field campaign in a Eucalypt forest in Tumbarumba, South-East Australia, in November 2006. The measured size range of ions was 0.34 to 40 nm and that of aerosol particles approximately 10 to 168 nm, and for observing their size distributions we used an Air Ion Spectrometer (AIS) and a Scanning Mobility Particle Sizer (SMPS). We also measured the hygroscopic and chemical properties of the particles with a Volatility-Humidity Tandem Differential Mobility Analyser (VH-TDMA). The total concentration of ultrafine aerosol particles was measured with a Condensational Particle Counter (CPC). Furthermore, we measured ambient concentrations of volatile organic compounds (VOC), SOx, NOx/NOy, and O3. Finally, we modelled the 96-h back trajectories of air masses arriving at the site and observed that the arrival directions varied greatly and included trajectories that travelled only over land as well as ones that travelled most of the time over the ocean. On the most polluted day, the air masses arrived approximately from the direction of greater Sydney / Newcastle coal mine area. The total concentration of ultrafine aerosol particles was approximately 3500 cm-3, and daytime aerosol formation took place on 64% of days with acceptable data. The dominant VOCs were isoprene, eucalyptol, a- and b-pinene, camphene, and limonene. The measured hygroscopic growth factors (Gh) at RH of 90% varied from 1.1 to 1.5. The smallest Gh were observed for aged accumulation mode particles in early mornings, and the largest Gh occurred for the freshly nucleated particles on Nov 10, the day with the highest concentration of SO2
Fast spectroscopy and imaging with the FORS2 HIT mode

The HIgh-Time resolution (HIT) mode of FORS2 has 3 sub-modes that allow for
imaging and spectroscopy over a range of timescales from milliseconds up to
seconds. It is the only high time resolution spectroscopy mode available on an
8m class telescope. In imaging mode, it can be used to measure the pulse of
pulsars and spinning white dwarfs in a variety of high throughput broad- and
narrow-band filters. In spectroscopy mode it can take up to 10 spectra per
second using a novel ''shift-and-wait'' clocking pattern for the CCD. It takes
advantage of the user-designed masks which can be inserted into FORS2 to allow
any two targets within the 6.8' x 6.8' field of view of FORS2 to be selected. A
number of integration, or more precisely 'wait', times are available, which
together with the high throughput GRISMs can observe the entire optical
spectrum on a range of timescales.Comment: 19 pages, 7 figures, to appear in "High Time Resolution Astrophysics,
  Galway 2006
High-Speed Optical Spectroscopy

The large surveys and sensitive instruments of modern astronomy are turning
ever more examples of variable objects, many of which are extending the
parameter space to testing theories of stellar evolution and accretion. Future
projects such as the Laser Interferometer Space Antenna (LISA) and the Large
Synoptic Survey Telescope (LSST) will only add more challenging candidates to
this list. Understanding such objects often requires fast spectroscopy, but the
trend for ever larger detectors makes this difficult. In this contribution I
outline the science made possible by high-speed spectroscopy, and consider how
a combination of the well-known progress in computer technology combined with
recent advances in CCD detectors may finally enable it to become a standard
tool of astrophysics.Comment: To appear in the proceedings of the meeting on High Time Resolution
  Astrophysics, Galway, June 200
Common Envelope Evolution Redux

Common envelopes form in dynamical time scale mass exchange, when the
envelope of a donor star engulfs a much denser companion, and the core of the
donor plus the dense companion star spiral inward through this dissipative
envelope. As conceived by Paczynski and Ostriker, this process must be
responsible for the creation of short-period binaries with degenerate
components, and, indeed, it has proven capable of accounting for short-period
binaries containing one white dwarf component. However, attempts to reconstruct
the evolutionary histories of close double white dwarfs have proven more
problematic, and point to the need for enhanced systemic mass loss, either
during the close of the first, slow episode of mass transfer that produced the
first white dwarf, or during the detached phase preceding the final, common
envelope episode. The survival of long-period interacting binaries with massive
white dwarfs, such as the recurrent novae T CrB and RS Oph, also presents
interpretative difficulties for simple energetic treatments of common envelope
evolution. Their existence implies that major terms are missing from usual
formulations of the energy budget for common envelope evolution. The most
plausible missing energy term is the energy released by recombination in the
common envelope, and, indeed, a simple reformulation the energy budget
explicitly including recombination resolves this issue.Comment: 25 pages, 6 figures. To appear in "Short Period Binary Stars", ed.
  E.F. Milone, D.A. Leahy, & D.W. Hobill (Springer
Accreting Neutron Stars in Low-Mass X-Ray Binary Systems

Using the Rossi X-ray Timing Explorer (RossiXTE), astronomers have discovered
that disk-accreting neutron stars with weak magnetic fields produce three
distinct types of high-frequency X-ray oscillations. These oscillations are
powered by release of the binding energy of matter falling into the strong
gravitational field of the star or by the sudden nuclear burning of matter that
has accumulated in the outermost layers of the star. The frequencies of the
oscillations reflect the orbital frequencies of gas deep in the gravitational
field of the star and/or the spin frequency of the star. These oscillations can
therefore be used to explore fundamental physics, such as strong-field gravity
and the properties of matter under extreme conditions, and important
astrophysical questions, such as the formation and evolution of millisecond
pulsars. Observations using RossiXTE have shown that some two dozen neutron
stars in low-mass X-ray binary systems have the spin rates and magnetic fields
required to become millisecond radio-emitting pulsars when accretion ceases,
but that few have spin rates above about 600 Hz. The properties of these stars
show that the paucity of spin rates greater than 600 Hz is due in part to the
magnetic braking component of the accretion torque and to the limited amount of
angular momentum that can be accreted in such systems. Further study will show
whether braking by gravitational radiation is also a factor. Analysis of the
kilohertz oscillations has provided the first evidence for the existence of the
innermost stable circular orbit around dense relativistic stars that is
predicted by strong-field general relativity. It has also greatly narrowed the
possible descriptions of ultradense matter.Comment: 22 pages, 7 figures, updated list of sources and references, to
  appear in "Short-period Binary Stars: Observation, Analyses, and Results",
  eds. E.F. Milone, D.A. Leahy, and D. Hobill (Dordrecht: Springer,
  http://www.springerlink.com
Modelling of metal forming processes and multi-physic coupling

http://congress.cimne.com/complas05/admin/Files/FilePaper/p377.pdfInternational audienceThe main physical phenomena which can be coupled with the mechanical computation of metal forming processes are analyzed. Recalling the classical thermal coupling, it is shown that a stronger numerical coupling is necessary when localization of the deformation occurs. Several situations where we have mechanical solid and liquid interactions with thermal coupling are briefly mentioned. A more complete description of electro magnetic and thermal coupling is given in view of induction heating. Finally the case of multi scale coupling for metallurgic microstructure evolution is introduced
Nautical Radar Measurements in Europe: Applications of WaMoS II as a Sensor for Sea State, Current and Bathymetry

This paper presents the remote sensing techniques of measuring sea states, currents and bathymetry by using an X-band nautical radar. It briefly describes the fundamental methods to infer sea state information (e.g. ocean wave and current parameters) from nautical radar imagery. In addition, this work describes in detail the performance of the Wave Monitoring System WaMoS II (a commercial system for real-time monitoring of wave fields based on nautical radar technology). Two examples of nautical radar applications are presented: the first application is an example of the standard WaMoS II installation for sea state measurements, and the second application shows results of a research project aiming at the determination of shallow water bathymetry by means of nautical radar imagery
Modelling the Overflows Across the Greenland–Scotland Ridge

The Atlantic Meridional Overturning Circulation (AMOC) is part of a global redistribution system in the ocean that carries vast amounts of mass, heat, and freshwater. Within the AMOC, water mass transformations in the Nordic Seas (NS) and the overflows across the Greenland-Scotland Ridge (GSR) contribute significantly to the overturning mass transport. The deep NS are separated by the GSR from direct exchange with the subpolar North Atlantic. Two deeper passages, Denmark Strait (DS, sill depth 630 m) and Faroe Bank Channel (FBC, sill depth 840 m), constrain the deep outflow. The outflow transports are assumed to be governed by hydraulic control (Whitehead 1989, 1998). According to the circulation scheme by Dickson and Brown (1994), there is an overflow of 2.9 Sv (1 Sv = 1 Sverdrup = 106 m3 s–1) through DS, 1.7 Sv through FBC and another 1 Sv from flow across the Iceland%Faroe Ridge (IFR). To the south of the GSR, the overflows sink to depth and then spread along the topography, eventually merging to form a deep boundary current in the western Irminger Sea. During the descent, the dense bottom water flow doubles its volume by entrainment of ambient waters (e.g. Price and Baringer 1994) so that there is a deep water transport of 13.3 Sv once the boundary current reaches Cape Farvel (Dickson and Brown 1994). Thus the overflows and the overflow-related part of the AMOC account for more than 70% of the maximum total overturning, which is estimated from observations to be about 18 Sv (e.g. Macdonald 1998
Soil quality and methods for its assessment

34 pages, 7 figures, 7 tables, 54 references.Environmental sustainability will only be achieved by maintenance and improvement of soil quality. Soil quality is considered as the capacity of a soil to function. Its assessment focuses on dynamic aspects to evaluate the sustainability of soil management practices. In this chapter, a wide perspective of soil quality and the complex task of its assessment, considering the inherent and dynamic factors, are introduced. It focuses on the possibilities of applying and integrating the accumulated knowledge in agroecological land evaluation in order to predict soil quality. Advanced information technologies in modern decision support tools enable the integration of large and complex databases, models, tools, and techniques, and are proposed to improve the decision-making process in soil quality management. Although universal recommendations on soil quality and sustainability of soil management must not be done, this chapter presents general trends in soil quality management strategies. This includes arable land identification, crop diversification, organic matter restoration, tillage intensity, and soil input rationalization.Peer reviewe