Lending of Last Resort, Moral Hazard and Twin Crises: Lessons from the Bulgarian Financial Crisis 1996/1997

In 1996/1997 Bulgaria was hit by a severe financial crisis, spreading from a banking crisis to a currency crisis. While being widely neglected by the financial crisis literature and the international discussion we argue that the Bulgarian Financial Crisis might serve as an illustrative example of a twin crisis primarily (but not only) due to systematic moral hazard behaviour of the banking sector. Thus, the Bulgarian Financial Crisis might be closer to the story of third generation moral hazard models of currency crises than the Asian Crisis. We also show how Bulgaria managed to overcome the crisis by introducing a second generation currency board allowing the central bank to act as a strictly limited lender of last resort thereby (hopefully) making the country less prone to a financial crisis in the future.http://deepblue.lib.umich.edu/bitstream/2027.42/39848/3/wp464.pd

Lending of Last Resort, Moral Hazard and Twin Crises: Lessons from the Bulgarian Financial Crisis 1996/1997

In 1996/1997 Bulgaria was hit by a severe financial crisis, spreading from a banking crisis to a currency crisis. While being widely neglected by the financial crisis literature and the international discussion we argue that the Bulgarian Financial Crisis might serve as an illustrative example of a twin crisis primarily (but not only) due to systematic moral hazard behaviour of the banking sector. Thus, the Bulgarian Financial Crisis might be closer to the story of third generation moral hazard models of currency crises than the Asian Crisis. We also show how Bulgaria managed to overcome the crisis by introducing a second generation currency board allowing the central bank to act as a strictly limited lender of last resort thereby (hopefully) making the country less prone to a financial crisis in the future.Financial Crises, Bulgaria, Lender of Last Resort, Twin Crises, Currency Boards

Hybrid system identification using switching density networks

Behaviour cloning is a commonly used strategy for imitation learning and can be extremely effective in constrained domains. However, in cases where the dynamics of an environment may be state dependent and varying, behaviour cloning places a burden on model capacity and the number of demonstrations required. This paper introduces switching density networks, which rely on a categorical reparametrisation for hybrid system identification. This results in a network comprising a classification layer that is followed by a regression layer. We use switching density networks to predict the parameters of hybrid control laws, which are toggled by a switching layer to produce different controller outputs, when conditioned on an input state. This work shows how switching density networks can be used for hybrid system identification in a variety of tasks, successfully identifying the key joint angle goals that make up manipulation tasks, while simultaneously learning image-based goal classifiers and regression networks that predict joint angles from images. We also show that they can cluster the phase space of an inverted pendulum, identifying the balance, spin and pump controllers required to solve this task. Switching density networks can be difficult to train, but we introduce a cross entropy regularisation loss that stabilises training

Spatial and Temporal Stability of Airglow Measured in the Meinel Band Window at 1191.3 nm

We report on the temporal and spatial fluctuations in the atmospheric brightness in the narrow band between Meinel emission lines at 1191.3 nm using an R=320 near-infrared instrument. We present the instrument design and implementation, followed by a detailed analysis of data taken over the course of a night from Table Mountain Observatory. The absolute sky brightness at this wavelength is found to be 5330 +/- 30 nW m^-2 sr^-1, consistent with previous measurements of the inter-band airglow at these wavelengths. This amplitude is larger than simple models of the continuum component of the airglow emission at these wavelengths, confirming that an extra emissive or scattering component is required to explain the observations. We perform a detailed investigation of the noise properties of the data and find no evidence for a noise component associated with temporal instability in the inter-line continuum. This result demonstrates that in several hours of ~100s integrations the noise performance of the instrument does not appear to significantly degrade from expectations, giving a proof of concept that near-IR line intensity mapping may be feasible from ground-based sites.Comment: 15 figures, submitted to PAS

Characterization of the CD14⁺⁺CD16⁺ Monocyte Population in Human Bone Marrow

Numerous studies have divided blood monocytes according to their expression of the surface markers CD14 and CD16 into following subsets: classical CD14(++)CD16(-), intermediate CD14(++)CD16(+) and nonclassical CD14(+)CD16(++) monocytes. These subsets differ in phenotype and function and are further correlated to cardiovascular disease, inflammation and cancer. However, the CD14/CD16 nature of resident monocytes in human bone marrow remains largely unknown. In the present study, we identified a major population of CD14(++)CD16(+) monocytes by using cryopreserved bone marrow mononuclear cells from healthy donors. These cells express essential monocyte-related antigens and chemokine receptors such as CD11a, CD18, CD44, HLA-DR, Ccr2, Ccr5, Cx3cr1, Cxcr2 and Cxcr4. Notably, the expression of Ccr2 was inducible during culture. Furthermore, sorted CD14(++)CD16(+) bone marrow cells show typical macrophage morphology, phagocytic activity, angiogenic features and generation of intracellular oxygen species. Side-by-side comparison of the chemokine receptor profile with unpaired blood samples also demonstrated that these rather premature medullar monocytes mainly match the phenotype of intermediate and partially of (non) classical monocytes. Together, human monocytes obviously acquire their definitive CD14/CD16 signature in the bloodstream and the medullar monocytes probably transform into CD14(++)CD16(-) and CD14(+)CD16(++) subsets which appear enriched in the periphery

Composing Diverse Policies for Temporally Extended Tasks

Robot control policies for temporally extended and sequenced tasks are often characterized by discontinuous switches between different local dynamics. These change-points are often exploited in hierarchical motion planning to build approximate models and to facilitate the design of local, region-specific controllers. However, it becomes combinatorially challenging to implement such a pipeline for complex temporally extended tasks, especially when the sub-controllers work on different information streams, time scales and action spaces. In this paper, we introduce a method that can compose diverse policies comprising motion planning trajectories, dynamic motion primitives and neural network controllers. We introduce a global goal scoring estimator that uses local, per-motion primitive dynamics models and corresponding activation state-space sets to sequence diverse policies in a locally optimal fashion. We use expert demonstrations to convert what is typically viewed as a gradient-based learning process into a planning process without explicitly specifying pre- and post-conditions. We first illustrate the proposed framework using an MDP benchmark to showcase robustness to action and model dynamics mismatch, and then with a particularly complex physical gear assembly task, solved on a PR2 robot. We show that the proposed approach successfully discovers the optimal sequence of controllers and solves both tasks efficiently.Comment: arXiv admin note: substantial text overlap with arXiv:1906.1009

Full-length amelogenin influences the differentiation of human dental pulp stem cells

Background: Amelogenin is an extracellular matrix protein well known for its role in the organization and mineralization of enamel. Clinically, it is used for periodontal regeneration and, due to its finding also in predentin and intercellular spaces of dental pulp cells, it has recently been suggested for pulp capping procedures. The aim of this study was to analyse in vitro the effect of the recombinant human full-length amelogenin on the growth and differentiation of human dental pulp stem cells (hDPSCs). Methods: Human DPSCs were treated with a supplement of amelogenin at a concentration of 10 ng/ml, 100 ng/ml and 1000 ng/ml. The groups were compared to the unstimulated control in terms of cell morphology and proliferation, mineralization and gene expression for ALP (alkaline phosphatase), DMP1 (dentin matrix protein-1) and DSPP (dentin sialophosphoprotein). Results: Amelogenin affects hDPSCs differently than PDL (periodontal ligament) cells and other cell lines. The proliferation rate at two weeks is significantly reduced in presence of the highest concentration of amelogenin as compared to the unstimulated control. hDPSCs treated with low concentrations present a downregulation of DMP1 and DSPP, which is significant for DSPP (p = 0.011), but not for DMP1 (p = 0.395). Conclusions: These finding suggest that the role of full-length amelogenin is not restricted to participation in tooth structure. It influences the differentiation of hDPSC according to various concentrations and this might impair the clinical results of pulp capping

Haematopoietic and cardiac GPR55 synchronize post-myocardial infarction remodelling

While classical cannabinoid receptors are known to crucially impact on myocardial infarction (MI) repair, a function of the cannabinoid-sensitive receptor GPR55 herein is poorly understood. We investigated the role of GPR55 in cardiac physiology and post-MI inflammation and remodelling. Global GPR55-/- and wildtype (WT) mice were basally characterized or assigned to 1, 3 or 28~days permanent MI and subsequently analysed via pro-inflammatory and pro-hypertrophic parameters. GPR55-/- deficiency was basally associated with bradycardia, increased diastolic LV volume and sarcomere length and a subtle inflammatory phenotype. While infarct size and myeloid cell infiltration were unaffected by GPR55 depletion, acute cardiac chemokine production was prolonged post-MI. Concurrently, GPR55-/- hearts exhibited a premature expansion of pro-reparative and phagocytic macrophages paralleled by early up-regulation of extracellular matrix (ECM) factors 3~days post-MI, which could be mimicked by sole haematopoietic GPR55 depletion. Moreover, global GPR55 deficiency mitigated MI-induced foetal gene re-programming and cardiomyocyte hypertrophy, culminating in aggravated LV dilatation and infarct expansion. GPR55 regulates cardiac homeostasis and ischaemia responses by maintaining adequate LV filling and modulating three crucial processes post-MI: wound healing kinetics, cardiomyocyte hypertrophy and maladaptive remodelling