Quasi-Exact Solvability and the direct approach to invariant subspaces

We propose a more direct approach to constructing differential operators that preserve polynomial subspaces than the one based on considering elements of the enveloping algebra of sl(2). This approach is used here to construct new exactly solvable and quasi-exactly solvable quantum Hamiltonians on the line which are not Lie-algebraic. It is also applied to generate potentials with multiple algebraic sectors. We discuss two illustrative examples of these two applications: an interesting generalization of the Lam\'e potential which posses four algebraic sectors, and a quasi-exactly solvable deformation of the Morse potential which is not Lie-algebraic.Comment: 17 pages, 3 figure

The social return on investment of a new approach to heart failure in the Spanish National Health System

AIMS: We aim to agree on a set of proposals to improve the current management of heart failure (HF) within the Spanish National Health System (SNHS) and apply the social return on investment (SROI) method to measure the social impact that these proposals would generate. METHODS AND RESULTS: A multidisciplinary working team of 16 experts was set up, with representation from the main stakeholders regarding HF: medical specialists (cardiologists, internal medicine physicians, general practitioners, and geriatric physicians), nursing professionals, health management professionals, patients, and informal caregivers. This team established a set of proposals to improve the management of HF according to the main areas of HF care: emergency and hospitalization, primary care, cardiology, and internal medicine. A forecast-type SROI method, with a 1-year time frame, was applied to measure the social impact resulting from the implementation of these proposals. The required investment and social return were estimated and summarized into a ratio indicating how much social return could be generated for each euro invested. Intangible returns were included and quantified through financial proxies. The approach to improve the management of HF consisted of 28 proposals, including the implementation of a case management nurse network, standardization of operational protocols, psychological support, availability of echocardiography machines at emergency departments, stationary units and primary care, early specialist visits after hospital discharge, and cardiac rehabilitation units, among others. These proposals would benefit not only patients and their informal caregivers but also the SNHS. Regarding patients, proposals would increase their autonomy in everyday activities, decrease anxiety, increase psychological and physical well-being, improve pharmacological adherence and self-care, enhance understanding of the disease, delay disease progression, expedite medical assessment, and prevent the decrease in work productivity associated with HF management. Regarding informal caregivers, proposals would increase their quality of life; improve their social, economic, and emotional well-being; and reduce their care burden. The SNHS would benefit from shorter stays of HF patients at intensive care units and reduction of hospitalizations and admissions to emergency departments. The investment needed to implement these proposals would amount to euro548m and yield a social return of euro1932m, that is, euro3.52 for each euro invested. CONCLUSIONS: The current management of HF could be improved by a set of proposals that resulted in an overall positive social return, varying between areas of analysis. This may guide the allocation of healthcare resources and improve the quality of life of patients with HF

Epigenetic Silencing of Tumor Suppressor miR-124 Directly Supports STAT3 Activation in Cutaneous T-Cell Lymphoma

Increasing evidence supports a potential role for STAT3 as a tumor driver in cutaneous T-cell lymphomas (CTCL). The mechanisms leading to STAT3 activation are not fully understood; however, we recently found that miR-124, a known STAT3 regulator, is robustly silenced in MF tumor-stage and CTCL cells. OBJECTIVE: We studied here whether deregulation of miR-124 contributes to STAT3 pathway activation in CTCL. METHODS: We measured the effect of ectopic mir-124 expression in active phosphorylated STAT3 (p-STAT3) levels and evaluated the transcriptional impact of miR-124-dependent STAT3 pathway regulation by expression microarray analysis. RESULTS: We found that ectopic expression of miR-124 results in massive downregulation of activated STAT3 in different CTCL lines, which resulted in a significant alteration of genetic signatures related with gene transcription and proliferation such as MYC and E2F. CONCLUSIONS: Our study highlights the importance of the miR-124/STAT3 axis in CTCL and demonstrates that the STAT3 pathway is regulated through epigenetic mechanisms in these cells. Since deregulated STAT3 signaling has a major impact on CTCL initiation and progression, a better understanding of the molecular basis of the miR-124/STAT3 axis may provide useful information for future personalized therapies

A hyperbolic slicing condition adapted to Killing fields and densitized lapses

We study the properties of a modified version of the Bona-Masso family of hyperbolic slicing conditions. This modified slicing condition has two very important features: In the first place, it guarantees that if a spacetime is static or stationary, and one starts the evolution in a coordinate system in which the metric coefficients are already time independent, then they will remain time independent during the subsequent evolution, {\em i.e.} the lapse will not evolve and will therefore not drive the time lines away from the Killing direction. Second, the modified condition is naturally adapted to the use of a densitized lapse as a fundamental variable, which in turn makes it a good candidate for a dynamic slicing condition that can be used in conjunction with some recently proposed hyperbolic reformulations of the Einstein evolution equations.Comment: 11 page

Do Credit Rating Agencies Add Value? Evidence from the Sovereign Rating Business Institutions

If rating agencies add no new information to markets, their actions are not a public policy concern. But as rating changes may be anticipated, testing whether ratings add value is not straightforward. This paper argues that ratings and spreads are both noisy signals of fundamentals and suggest ratings add value if, controlling for spreads, they help explain other variables. The paper additionally analyzes the different actions (ratings and outlooks) of the three leading agencies for sovereign debt, also considering the differing effects of more or less anticipated events. The results are consistent across a wide range of tests. Ratings do matter and hence how the market for ratings functions may be a public policy concern

Vortices in a Bose-Einstein condensate confined by an optical lattice

We investigate the dynamics of vortices in repulsive Bose-Einstein condensates in the presence of an optical lattice (OL) and a parabolic magnetic trap. The dynamics is sensitive to the phase of the OL potential relative to the magnetic trap, and depends less on the OL strength. For the cosinusoidal OL potential, a local minimum is generated at the trap's center, creating a stable equilibrium for the vortex, while in the case of the sinusoidal potential, the vortex is expelled from the center, demonstrating spiral motion. Cases where the vortex is created far from the trap's center are also studied, revealing slow outward-spiraling drift. Numerical results are explained in an analytical form by means of a variational approximation. Finally, motivated by a discrete model (which is tantamount to the case of the strong OL lattice), we present a novel type of vortex consisting of two pairs of anti-phase solitons.Comment: 10 pages, 6 figure

Geology and rural landscapes in central Spain (Guadalajara, Castilla—La Mancha)

Methods commonly used in regional geological analysis were employed to study the visual landscapes of the Sigüenza–Molina de Aragón area (Spain). Landscape data were compiled to produce a landscape map and a photograph catalogue. Lithological composition, tectonic structure and recent erosive processes are the main factors controlling the visual landscapes. Territorial properties, such as colours and agricultural capacities, are controlled by these geological characteristics. The landscape map and the photographic catalogue is the main contribution of this paper. The first level of landscape classification distinguishes zones with dominance of either flat, concave or convex areas. Other parts of the territory are, however, composed of concave and convex combinations that originate hybrid orographic structures. In a second level of classification, several subdivisions for each of these types are established

Regularity Properties and Pathologies of Position-Space Renormalization-Group Transformations

We reconsider the conceptual foundations of the renormalization-group (RG) formalism, and prove some rigorous theorems on the regularity properties and possible pathologies of the RG map. Regarding regularity, we show that the RG map, defined on a suitable space of interactions (= formal Hamiltonians), is always single-valued and Lipschitz continuous on its domain of definition. This rules out a recently proposed scenario for the RG description of first-order phase transitions. On the pathological side, we make rigorous some arguments of Griffiths, Pearce and Israel, and prove in several cases that the renormalized measure is not a Gibbs measure for any reasonable interaction. This means that the RG map is ill-defined, and that the conventional RG description of first-order phase transitions is not universally valid. For decimation or Kadanoff transformations applied to the Ising model in dimension $d \ge 3$, these pathologies occur in a full neighborhood $\{ \beta > \beta_0 ,\, |h| < \epsilon(\beta) \}$ of the low-temperature part of the first-order phase-transition surface. For block-averaging transformations applied to the Ising model in dimension $d \ge 2$, the pathologies occur at low temperatures for arbitrary magnetic-field strength. Pathologies may also occur in the critical region for Ising models in dimension $d \ge 4$. We discuss in detail the distinction between Gibbsian and non-Gibbsian measures, and give a rather complete catalogue of the known examples. Finally, we discuss the heuristic and numerical evidence on RG pathologies in the light of our rigorous theorems.Comment: 273 pages including 14 figures, Postscript, See also ftp.scri.fsu.edu:hep-lat/papers/9210/9210032.ps.

Are Public and Private R&D Investments Complements or Substitutes?

We develop a general equilibrium model with heterogeneous firms à la Melitz (2003), where both the government and firms can invest into R&D to improve the country's technological potential. A higher technological potential raises the average productivity of firms, thus implying lower consumer prices, and eventually leads to a welfare gain. The government's public and firms' private investments are modelled in a three-stage game, in which the government in the first stage invests into a basic research level, and then firms conduct private R&D building on this publicly provided 'technology' in the second stage. We find that private R&D investments are hump-shaped with respect to the basic research level. For lower levels public and private investments are complements, while for higher levels they are substitutes.Der Artikel untersucht in einem allgemeinen Gleichgewichtsmodell den Zusammenhang zwischen öffentlichen und privaten Investitionen in Forschung und Entwicklung. Öffentliche Investitionen des Staates sowie private Investitionen von Firmen verbessern gemeinsam die durchschnittliche Produktivität der Firmen. Die höhere durchschnittliche Produktivität führt zu sinkenden Konsumentenpreisen und daraus resultierend zu Wohlfahrtsgewinnen. In einem dreistufigen Spiel investiert in der ersten Stufe der Staat in eine zugrunde liegende 'Technologie'. In der zweiten Stufe treffen Firmen ihre Investitionsentscheidung, basierend auf den öffentlichen Investitionen und der bereitgestellten Technologie. Für die Beziehung zwischen öffentlichen und privaten Investitionen in Forschung und Entwicklung finden wir einen umgekehrt u?förmigen Zusammenhang. Für öffentliche Investitionen unterhalb eines bestimmten Schwellenwertes besteht ein komplementärer Zusammenhang, während bei öffentlichen Investitionen, die diesen Schwellenwert überschreiten, ein substitutiver Zusammenhang zwischen öffentlichen und privaten Investitionen existiert