Prolongation structure of the KdV equation in the bilinear form of Hirota

The prolongation structure of the KdV equation in the bilinear form of Hirota is determined, the resulting Lie algebra is realised and the Backlund transformation obtained from the prolongation structure is derived. The results are compared with those found by Wahlquist and Estabrook (1975) and by Hirota (1980)

The AM Canum Venaticorum binary SDSS J173047.59+554518.5

The AM Canum Venaticorum (AM CVn) binaries are a rare group of hydrogen-deficient, ultrashort period, mass-transferring white dwarf binaries and are possible progenitors of Type Ia supernovae. We present time-resolved spectroscopy of the recently discovered AM CVn binary SDSS J173047.59+554518.5. The average spectrum shows strong double-peaked helium emission lines, as well as a variety of metal lines, including neon; this is the second detection of neon in an AM CVn binary, after the much brighter system GP Com. We detect no calcium in the accretion disc, a puzzling feature that has been noted in many of the longer period AM CVn binaries. We measure an orbital period, from the radial velocities of the emission lines, of 35.2 ± 0.2 min, confirming the ultracompact binary nature of the system. The emission lines seen in SDSS J1730 are very narrow, although double-peaked, implying a low-inclination, face-on accretion disc; using the measured velocities of the line peaks, we estimate i ≤ 11°. This low inclination makes SDSS J1730 an excellent system for the identification of emission lines

Neuroimaging in Functional Movement Disorders.

PURPOSE OF REVIEW: Functional movement disorders are common and disabling causes of abnormal movement control. Here, we review the current state of the evidence on the use of neuroimaging in Functional movement disorders, particularly its role in helping to unravel the pathophysiology of this enigmatic condition. RECENT FINDINGS: In recent years, there has been a shift in thinking about functional movement disorder, away from a focus on high-level psychological precipitants as in Freudian conversion theories, or even an implicit belief they are 'put-on' for secondary gain. New research has emphasised novel neurobiological models incorporating emotional processing, self-representation and agency. Neuroimaging has provided new insights into functional movement disorders, supporting emerging neurobiological theories implicating dysfunctional emotional processing, self-image and sense of agency. Recent studies have also found subtle structural brain changes in patients with functional disorders, arguing against a strict functional/structural dichotomy

Model simulations of the changing distribution of Ozone and its radiative forcing of climate: past, present and future

A background tropospheric chemistry model that is coupled to the general circulation model ECHAM4 is used to calculate tropospheric ozone with preindustrial, present-day and future (IS92a) emission scenarios as boundary conditions. The model calculates separate contributions to tropospheric ozone levels from stratosphere-troposphere exchange (STE) and from photo- chemical production in the troposphere. In the preindustrial atmosphere, the simulated annual tropospheric ozone content is 190 Tg 03, of which about 110 Tg 03 originates from the strato- sphere. In the present-day simulation the ozone content is about 80 Tg 03 larger, mainly due to O3 precursor emissions from industrial processes in the NH and from biomass burning in trop- ical regions. In the next few decades, industrial growth is expected to occur mainly at NH (sub) tropical latitudes, leading to an additional increase of the tropospheric ozone budget by 60 Tg 03. We calculate a global and annual average radiative forcing by tropospheric ozone perturbations of 0.42 w m-2 creases in the next few decades of 0.31 W m-2 for the present-day simulation, and an additional forcing due to ozone in- The model results indicate that the amount of tropospheric ozone from stratospheric origin remains relatively unaffected by the changing pho- tochemistry

Hierarchical index sets in algebraic modelling languages

Multi-dimensional algebraic modelling languages make extensive use of simple and compound index sets. In this paper the multi-dimensional modelling paradigm is extended with the concept of a hierarchical index set to support the use of hierarchical data structures. The appropriate reference and indexing mechanisms are introduced, together with mechanisms to support various set operations. Special attention is paid to the Cartesian product of two hierarchical index sets. The modelling of multi-stage programming models is supported through the introduction of a hierarchical indexing mechanism. The extensions proposed in this paper are compared to existing facilities designed to support the modelling of hierarchical structures

Prolongation structures for supersymmetric equations

The well known prolongation technique of Wahlquist and Estabrook (1975) for nonlinear evolution equations is generalized for supersymmetric equations and applied to the supersymmetric extension of the KdV equation of Manin-Radul. Using the theory of Kac-Moody Lie superalgebras, the explicit form of the resulting Lie superalgebra is determined. It is shown to be isomorphic to RMR*Cov+(C(2), sigma ), where RMR is an eight-dimensional radical. An auto-Backlund transformation is derived from the prolongation structure and the relationship with known solution methods of the SKdV equation is analysed. In addition it is indicated how a super-position principle for the SKdV equation can be obtaine

The decentralization of Social Assistance and the rise of Disability Insurance enrolment

In this paper, we assess spillover effects of Social Assistance (SA) decentralization in the Netherlands, in particular towards (a centrally administered) Disability Insurance scheme (DI). DI enrolment has increased strongly since the decentralization of SA. Many economists and policymakers believe that fiscal decentralization, the decentralization of government expenditures to local governments, enhances public sector efficiency. Vertical externalities – i.e. spillovers between local and central government – may however undo part of this advantage. In this paper, we assess spillover effects of Social Assistance (SA) decentralization in the Netherlands, in particular towards (a centrally administered) Disability Insurance scheme (DI). DI enrolment strongly increased since the decentralization of SA. We find that the sensitivity of local DI enrolment with respect to the stock of local SA recipients has increased over time, given that we control for both observed and unobserved disability risk factors. IV estimates show that, since the decentralization of SA, at least one third of DI inflow was diverted from SA.

Mesenchymal stem cells for management of rheumatoid arthritis : immune modulation, repair or both?

The authors are grateful for support to their research from Arthritis Research UK (grants 19271, 19429, 19667, 20050, 20775) and the Medical Research Council (grant no. MR/L020211/1)Peer reviewedPostprin