4,174 research outputs found
Protectionist Responses to the Crisis: Global Trends and Implications
In this paper we take a systematic look at recent trends in global protectionism and at the potential implications of a protectionist backlash for economic growth, using results from the recent economic literature and new model simulations. We find that there has so far been a moderate increase in actual protectionist measures to restrict trade through tariff and non-tariff barriers. At the same time, evidence from surveys shows that public pressure for more economic protection has been mounting since the mid-2000s, and has possibly intensified since the start of the financial crisis. However, no World Trade Organization (WTO) member has retreated into widespread trade restrictions or protectionism to date. Our model-based simulations suggest that the impairment of the global flow of trade would hamper the recovery from the crisis, as well as the long-term growth of the global economy. At the same time, it is unlikely that protectionism would help to correct existing current account imbalances. Moreover, the countries implementing protectionist measures should expect a deterioration of their international competitiveness, which would further affect the potential for longer-term real GDP growth.Protectionism ; trade ; financial crisis ; competitiveness ; World Trade Organization ; global imbalances.
Circular geodesics and thick tori around rotating boson stars
Accretion disks play an important role in the evolution of their relativistic
inner compact objects. The emergence of a new generation of interferometers
will allow to resolve these accretion disks and provide more information about
the properties of the central gravitating object. Due to this instrumental leap
forward it is crucial to investigate the accretion disk physics near various
types of inner compact objects now to deduce later constraints on the central
objects from observations. A possible candidate for the inner object is the
boson star. Here, we will try to analyze the differences between accretion
structures surrounding boson stars and black holes. We aim at analysing the
physics of circular geodesics around boson stars and study simple thick
accretion tori (so-called Polish doughnuts) in the vicinity of these stars. We
realize a detailed study of the properties of circular geodesics around boson
stars. We then perform a parameter study of thick tori with constant angular
momentum surrounding boson stars. This is done using the boson star models
computed by a code constructed with the spectral solver library KADATH. We
demonstrate that all the circular stable orbits are bound. In the case of a
constant angular momentum torus, a cusp in the torus surface exists only for
boson stars with a strong gravitational scalar field. Moreover, for each inner
radius of the disk, the allowed specific angular momentum values lie within a
constrained range which depends on the boson star considered. We show that the
accretion tori around boson stars have different characteristics than in the
vicinity of a black hole. With future instruments it could be possible to use
these differences to constrain the nature of compact objects.Comment: Accepted for publication in CQ
ISS Expeditions 16 through 20: Chemical Analysis Results for Potable Water
During the 2-year span from Expedition 16 through Expedition 20, the chemical quality of the potable water onboard the International Space Station (ISS) was verified safe for crew consumption through the return and chemical analysis of archival water samples by the Water and Food Analytical Laboratory (WAFAL) at Johnson Space Center (JSC). Reclaimed cabin humidity condensate and Russian ground-supplied water were the principal sources of potable water for Expeditions 16 through 18. During Expedition 18 the U.S. water processor assembly was delivered, installed, and tested during a 90-day checkout period. Beginning with Expedition 19, U.S. potable water recovered from a combined waste stream of humidity condensate and pretreated urine was also available for ISS crew use. A total of 74 potable water samples were collected using U.S. sampling hardware during Expeditions 16 through 20 and returned on both Shuttle and Soyuz vehicles. The results of JSC chemical analyses of these ISS potable water samples are presented in this paper. Eight potable water samples collected in flight with Russian hardware were also received for analysis, as well as 5 preflight samples of Rodnik potable water delivered to ISS on Russian Progress vehicles 28 to 34. Analytical results for these additional potable water samples are also reported and discussed
Pd/Cu Site Interchange and Non-Fermi-Liquid Behavior in UCu_4Pd
X-ray-absorption fine-structure measurements of the local structure in
UCu_4Pd are described which indicate a probable lattice-disorder origin for
non-Fermi-liquid behavior in this material. Short Pd-Cu distances are observed,
consistent with 24 +/- 3% of the Pd atoms occupying nominally Cu sites. A
"Kondo disorder" model, based on the effect on the local Kondo temperature T_K
of this interchange and some additional bond-length disorder, agrees
quantitatively with previous experimental susceptibility data, and therefore
also with specific heat and magnetic resonance experiments.Comment: 4 pages, 3 PostScript figures, to be published in PR
Time-dependent perturbation theory for vibrational energy relaxation and dephasing in peptides and proteins
Without invoking the Markov approximation, we derive formulas for vibrational
energy relaxation (VER) and dephasing for an anharmonic system oscillator using
a time-dependent perturbation theory. The system-bath Hamiltonian contains more
than the third order coupling terms since we take a normal mode picture as a
zeroth order approximation. When we invoke the Markov approximation, our theory
reduces to the Maradudin-Fein formula which is used to describe VER properties
of glass and proteins. When the system anharmonicity and the renormalization
effect due to the environment vanishes, our formulas reduce to those derived by
Mikami and Okazaki invoking the path-integral influence functional method [J.
Chem. Phys. 121 (2004) 10052]. We apply our formulas to VER of the amide I mode
of a small amino-acide like molecule, N-methylacetamide, in heavy water.Comment: 16 pages, 5 figures, 5 tables, submitted to J. Chem. Phy
Fractal Analysis of Protein Potential Energy Landscapes
The fractal properties of the total potential energy V as a function of time
t are studied for a number of systems, including realistic models of proteins
(PPT, BPTI and myoglobin). The fractal dimension of V(t), characterized by the
exponent \gamma, is almost independent of temperature and increases with time,
more slowly the larger the protein. Perhaps the most striking observation of
this study is the apparent universality of the fractal dimension, which depends
only weakly on the type of molecular system. We explain this behavior by
assuming that fractality is caused by a self-generated dynamical noise, a
consequence of intermode coupling due to anharmonicity. Global topological
features of the potential energy landscape are found to have little effect on
the observed fractal behavior.Comment: 17 pages, single spaced, including 12 figure
Spin-orbit splitting of image states
We quantify the effect of the spin-orbit interaction on the Rydberg-like
series of image state electrons at the (111) and (001) surface of Ir, Pt and
Au. Using relativistic multiple-scattering methods we find Rashba-like
dispersions with Delta E(K)=gamma K with values of gamma for n=1 states in the
range 38-88 meV Angstrom. Extending the phase-accumulation model to include
spin-orbit scattering we find that the splittings vary like 1/(n+a)^3 where a
is the quantum defect and that they are related to the probability of spin-flip
scattering at the surface. The splittings should be observable experimentally
being larger in magnitude than some exchange-splittings that have been resolved
by inverse photoemission, and are comparable to linewidths from inelastic
lifetimes.Comment: 10 pages, 4 figure
International Space Station Potable Water Characterization for 2013
In this post-construction, operational phase of International Space Station (ISS) with an ever-increasing emphasis on its use as a test-bed for future exploration missions, the ISS crews continue to rely on water reclamation systems for the majority of their water needs. The onboard water supplies include U.S. Segment potable water from humidity condensate and urine, Russian Segment potable water from condensate, and ground-supplied potable water, as reserve. In 2013, the cargo returned on the Soyuz 32-35 flights included archival potable water samples collected from Expeditions 34-37. The former Water and Food Analytical Laboratory (now Toxicology and Evironmental Chemistry Laboratory) at the NASA Johnson Space Center continued its long-standing role of performing chemical analyses on ISS return water samples to verify compliance with potable water quality specifications. This paper presents and discusses the analytical results for potable water samples returned from Expeditions 34-37, including a comparison to ISS quality standards. During the summer of 2013, the U.S. Segment potable water experienced a third temporary rise and fall in total organic carbon (TOC) content, as the result of organic contamination breaking through the water system's treatment process. Analytical results for the Expedition 36 archival samples returned on Soyuz 34 confirmed that dimethylsilanediol was once again the responsible contaminant, just as it was for the previous comparable TOC rises in 2010 and 2012. Discussion herein includes the use of the in-flight total organic carbon analyzer (TOCA) as a key monitoring tool for tracking these TOC rises and scheduling appropriate remediation
Chemical Analysis Results for Potable Water from ISS Expeditions 21 to 25
The Johnson Space Center Water and Food Analytical Laboratory (WAFAL) performed detailed ground-based analyses of archival water samples for verification of the chemical quality of the International Space Station (ISS) potable water supplies for Expeditions 21 to 25. Over a 14-month period, the Space Shuttle visited the ISS on five occasions to complete construction and deliver supplies. The onboard supplies of potable water available for consumption by the Expeditions 21 to 25 crews consisted of Russian ground-supplied potable water, Russian potable water regenerated from humidity condensate, and US potable water recovered from urine distillate and condensate. Chemical archival water samples that were collected with U.S. hardware during Expeditions 21 to 25 were returned on Shuttle flights STS-129 (ULF3), STS-130 (20A), STS-131 (19A), STS-132 (ULF4) and STS-133 (ULF5), as well as on Soyuz flights 19-22. This paper reports the analytical results for the returned archival water samples and evaluates their compliance with ISS water quality standards. The WAFAL also received and analyzed aliquots of some Russian potable water samples collected in-flight and pre-flight samples of Rodnik potable water delivered to the Station on the Russian Progress vehicle during Expeditions 21 to 25. These additional analytical results are also reported and discussed in this paper
International Space Station Potable Water Characterization for 2013
In this post-construction, operational phase of International Space Station (ISS) with an ever-increasing emphasis on its use as a test-bed for future exploration missions, the ISS crews continue to rely on water reclamation systems for the majority of their water needs. The onboard water supplies include US Segment potable water from humidity condensate and urine, Russian Segment potable water from condensate, and ground-supplied potable water, as reserve. In 2013, the cargo returned on the Soyuz 32-35 flights included archival potable water samples collected from Expeditions 34-37. The Water and Food Analytical Laboratory at the NASA Johnson Space Center continued its long-standing role of performing chemical analyses on ISS return water samples to verify compliance with potable water quality specifications. This paper presents and discusses the analytical results for potable water samples returned from Expeditions 34-37, including a comparison to ISS quality standards. During the summer of 2013, the U.S. Segment potable water experienced an anticipated temporary rise and fall in total organic carbon (TOC) content, as the result of organic contamination breaking through the water system's treatment process. Analytical results for the Expedition 36 archival samples returned on Soyuz 34 confirmed that dimethylsilanediol was once again the responsible contaminant, just as it was for comparable TOC rises in 2010 and 2012. Discussion herein includes the use of the in-flight Total Organic Carbon Analyzer (TOCA) as a key monitoring tool for tracking these TOC rises and scheduling appropriate remediation action
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