1,342 research outputs found
Conditions for the Quantum to Classical Transition: Trajectories vs. Phase Space Distributions
We contrast two sets of conditions that govern the transition in which
classical dynamics emerges from the evolution of a quantum system. The first
was derived by considering the trajectories seen by an observer (dubbed the
``strong'' transition) [Bhattacharya, et al., Phys. Rev. Lett. 85: 4852
(2000)], and the second by considering phase-space densities (the ``weak''
transition) [Greenbaum, et al., Chaos 15, 033302 (2005)]. On the face of it
these conditions appear rather different. We show, however, that in the
semiclassical regime, in which the action of the system is large compared to
, and the measurement noise is small, they both offer an essentially
equivalent local picture. Within this regime, the weak conditions dominate
while in the opposite regime where the action is not much larger than Planck's
constant, the strong conditions dominate.Comment: 8 pages, 2 eps figure
Bank Loan Commitments and Interest Rate Volatility
Bank loan commitments are examined in the context of option pricing models and a valuation formula is obtained. The partial takedown phenomenon, which is both distinctive and vexatious, is considered in detail. Finally, extimates of the value of U.S. bank loan commitments and their sensitivity to interest rate changes are provided.
Rapid methods of landslide hazard mapping : Fiji case study
A landslide hazard probability map can help planners (1) prepare for, and/or mitigate against,
the effects of landsliding on communities and infrastructure, and (2) avoid or minimise the
risks associated with new developments. The aims of the project were to establish, by means
of studies in a few test areas, a generic method by which remote sensing and data analysis
using a geographic information system (GIS) could provide a provisional landslide hazard
zonation map. The provision of basic hazard information is an underpinning theme of the
UN’s International Decade for Natural Disaster Reduction (IDNDR). It is an essential
requirement for disaster preparedness and mitigation planning. This report forms part of BGS
project 92/7 (R5554) ‘Rapid assessment of landslip hazards’ Carried out under the ODA/BGS
Technology Development and Research Programme as part of the British Government’s
provision of aid to developing countries. It provides a detailed technical account of work
undertaken in a test area in Viti Levu in collaboration with Fiji Mineral Resources
Department. The study represents a demonstration of a methodology that is applicable to
many developing countries.
The underlying principle is that relationships between past landsliding events, interpreted
from remote sensing, and factors such as the geology, relief, soils etc provide the basis for
modelling where future landslides are most likely to occur. This is achieved using a GIS by
‘weighting’ each class of each variable (e.g. each lithology ‘class’ of the variable ‘geology’)
according to the proportion of landslides occurring within it compared to the regional
average. Combinations of variables, produced by summing the weights in individual classes,
provide ‘models’ of landslide probability. The approach is empirical but has the advantage
of potentially being able to provide regional scale hazard maps over large areas quickly and
cheaply; this is unlikely to be achieved using conventional ground-based geotechnical
methods.
In Fiji, landslides are usually triggered by intense rain storms commonly associated with
tropical cyclones. However, the regional distribution of landslides has not been mapped nor
is it known how far geology and landscape influence the location and severity of landsliding
events. The report discusses the remote sensing and GIS methodology, and describes the
results of the pilot study over an area of 713 km2 in south east Viti Levu. The landslide
model uses geology, elevation, slope angle, slope aspect, soil type, and forest cover as
inputs. The resulting provisional landslide hazard zonation map, divided into high, medium
and low zones of landslide hazard probability, suggests that whilst rainfall is the immediate
cause, others controls do exert a significant influence. It is recommended that consideration
be given in Fiji to implementing the techniques as part of a national strategic plan for
landslide hazard zonation mapping
Information Reusability, Competition and Bank Asset Quality
The paper explains the recent decline in bank asset quality using the notion of information reusability. Banks are viewed as information processors; they exist because of their advantage in extracting the surplus associated with the reusability of borrower-specific information. It is shown that a bank's incentive to screen loan applicants, and hence maintain the quality of its assets, depends on the surplus this screening can produce, which in turn depends on information reusability. Two recent changes in banks' operating environment are increased competition and greater temporal volatility in borrower credit risks. The former has directly reduced banks' informational surplus while the latter has impaired information reusability. Hence screening expenditures have been reduced and the diminution of screening has lowered the quality of bank assets. It is also shown that an increase in deposit insurance premia has an effect similar to that of narrowing interest spreads and therefore will result in reduced asset screening and impaired asset quality.
Bank Funding Modes
We examine a bank's choice of whether to fund the loans it originates by emitting deposits or to sell the loans to investors. With common knowledge of loan quality and laissez faire banking, we find that the choice is irrelevant. With asymmetric information but without government intervention, we find that better quality assets will be sold (securitized) and poorer quality assets will be funded with deposits. Public regulation can influence the bank's choice; subsidies can cause a bank to favor deposit funding, but mutual funds and third-party insurers may mitigate the effects of governmental subsidies.
Eculizumab is a safe and effective treatment in pediatric patients with atypical hemolytic uremic syndrome
Atypical hemolytic uremic syndrome (aHUS) is caused by alternative complement pathway dysregulation, leading to systemic thrombotic microangiopathy (TMA) and severe end-organ damage. Based on 2 prospective studies in mostly adults and retrospective data in children, eculizumab, a terminal complement inhibitor, is approved for aHUS treatment. Here we prospectively evaluated efficacy and safety of weight-based dosing of eculizumab in eligible pediatric patients with aHUS in an open-label phase II study. The primary end point was complete TMA response by 26 weeks. Twenty-two patients (aged 5 months-17 years) were treated; 16 were newly diagnosed, 12 had no prior plasma exchange/infusion during current TMA symptomatology, 11 received baseline dialysis, and 2 had prior renal transplants. By week 26, 14 achieved a complete TMA response, 18 achieved hematologic normalization, and 16 had 25% or better improvement in serum creatinine. Plasma exchange/infusion was discontinued in all, and 9 of the 11 patients who required dialysis at baseline discontinued, whereas none initiated new dialysis. Eculizumab was well tolerated; no deaths or meningococcal infections occurred. Bone marrow failure, wrist fracture, and acute respiratory failure were reported as unrelated severe adverse events. Thus, our findings establish the efficacy and safety of eculizumab for pediatric patients with aHUS and are consistent with proposed immediate eculizumab initiation following diagnosis in children
The puzzling first-order phase transition in water-glycerol mixtures
© the Owner Societies 2015. Over the last decade, discussions on a possible liquid-liquid transition (LLT) have strongly intensified. The LLT proposed by several authors focused mostly on explaining the anomalous properties of water in a deeply supercooled state. However, there have been no direct experimental observations yet of LLT in bulk water in the so-called 'no man's land', where water exists only in the crystalline states. Recently, a novel experimental strategy to detect LLT in water has been employed using water-glycerol (W-G) mixtures, because glycerol can generate a strong hindrance for water crystallization. As a result, the observed first-order phase transition at a concentration of glycerol around cg ≈ 20 mol% was ascribed to the LLT. Here we show unambiguously that the first order phase transition in W-G mixtures is caused by the ice formation. We provide additional dielectric measurements, applying specific annealing temperature protocols in order to reinforce this conclusion. We also provide an explanation, why such a phase transition occurs only in the narrow glycerol concentration range. These results clearly demonstrate the danger of analysis of phase-separating liquids to gain better insights into water dynamics. These liquids have complex phase behavior that is affected by temperature, phase stability and segregation, viscosity and nucleation, and finally by crystallization, that might lead to significant misinterpretations
The low-temperature dynamic crossover in the dielectric relaxation of ice I<inf>h</inf>
© 2017 the Owner Societies. Based on the idea of defect migration as the principal mechanism in the dielectric relaxation of ice I h , the concept of low-temperature dynamic crossover was proposed. It is known that at high temperatures, the diffusion of Bjerrum and ionic defects is high and their movement may be considered to be independent. Simple switching between these two mechanisms leads to a dynamic crossover at ∼235 K. By introducing coupling between the Bjerrum and ionic defects, it is possible to describe the smooth bend in the relaxation time at low temperatures in ice I h . However, because the mobility of Bjerrum orientation defects slows down at low temperatures, they may create blockages for proton hopping. The trapping of ionic defects by L-D defects for a long period of time leads to an increase in the relaxation time and causes a low-temperature crossover. This model was validated by experimental dielectric measurements using various temperature protocols
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