657 research outputs found

    Bank Lending with Imperfect Competition and Spillover Effects

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    We examine bank lending decisions in an economy with spillover effects in the creation of new investment opportunities and asymmetric information in credit markets. We examine pricesetting equilibria with horizontally differentiated banks. If bank lending takes place under a weak corporate governance mechanism and is fraught with agency problems and ineffective bank monitoring, then an equilibrium emerges in which loan supply is strategically restricted. In this equilibrium, the loan restriction, the “under-lending?strategy, provides an advantage to one bank by increasing its market share and sustaining monopoly interest rates. The bank’s incentives for doing so increase under conditions of increased volatility of lending capacities of banks, more severe borrower-side moral hazard, and lower returns on the investment projects. Although this equilibrium is not always unique, with poor bank monitoring and corporate governance, a more intense banking competition renders the bad equilibrium the unique outcome.Bank lending, threshold effects, underlending equilibria, interest rate competition.

    Density-matrix renormalization group: a pedagogical introduction

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    The physical properties of a quantum many-body system can, in principle, be determined by diagonalizing the respective Hamiltonian, but the dimensions of its matrix representation scale exponentially with the number of degrees of freedom. Hence, only small systems that are described through simple models can be tackled via exact diagonalization. To overcome this limitation, numerical methods based on the renormalization group paradigm that restrict the quantum many-body problem to a manageable subspace of the exponentially large full Hilbert space have been put forth. A striking example is the density-matrix renormalization group (DMRG), which has become the reference numerical method to obtain the low-energy properties of one-dimensional quantum systems with short-range interactions. Here, we provide a pedagogical introduction to DMRG, presenting both its original formulation and its modern tensor-network-based version. This colloquium sets itself apart from previous contributions in two ways. First, didactic code implementations are provided to bridge the gap between conceptual and practical understanding. Second, a concise and self-contained introduction to the tensor network methods employed in the modern version of DMRG is given, thus allowing the reader to effortlessly cross the deep chasm between the two formulations of DMRG without having to explore the broad literature on tensor networks. We expect this pedagogical review to find wide readership amongst students and researchers who are taking their first steps in numerical simulations via DMRG.Comment: 30 pages, 17 figure

    Ultrasonic tissue characterization of vulnerable carotid plaque: correlation between videodensitometric method and histological examination

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    BACKGROUND: To establish the correlation between quantitative analysis based on B-mode ultrasound images of vulnerable carotid plaque and histological examination of the surgically removed plaque, on the basis of a videodensitometric digital texture characterization. METHODS: Twenty-five patients (18 males, mean age 67 ± 6.9 years) admitted for carotid endarterectomy for extracranial high-grade internal carotid artery stenosis (≥ 70% luminal narrowing) underwent to quantitative ultrasonic tissue characterization of carotid plaque before surgery. A computer software (Carotid Plaque Analysis Software) was developed to perform the videodensitometric analysis. The patients were divided into 2 groups according to symptomatology (group I, 15 symptomatic patients; and group II, 10 patients asymptomatic). Tissue specimens were analysed for lipid, fibromuscular tissue and calcium. RESULTS: The first order statistic parameter mean gray level was able to distinguish the groups I and II (p = 0.04). The second order parameter energy also was able to distinguish the groups (p = 0,02). A histological correlation showed a tendency of mean gray level to have progressively greater values from specimens with < 50% to >75% of fibrosis. CONCLUSION: Videodensitometric computer analysis of scan images may be used to identify vulnerable and potentially unstable lipid-rich carotid plaques, which are less echogenic in density than stable or asymptomatic, more densely fibrotic plaques

    Reaching all in rural sanitation: experiences from inclusive programming in five countries

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    © 2020, © 2020 Informa UK Limited, trading as Taylor & Francis Group. There is a need to reflect on approaches to reaching all in rural sanitation, given evidence that disadvantaged groups often miss out on benefits from programmes. This article presents approaches from area-wide rural sanitation programming undertaken by SNV across five countries. Analysis identified ten strategies used in combination to support inclusion. The article describes the strategies and their application, then presents four implications for the rural sanitation sector: the value of a “toolbox” approach; co-creation of strategies with stakeholders; recognition of local government as a driver of inclusive services; and the need to strengthen evidence on how strategies contribute to success

    Circulating endothelial cell-derived extracellular vesicles mediate the acute phase response and sickness behaviour associated with CNS inflammation.

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    Brain injury elicits a systemic acute-phase response (APR), which is responsible for co-ordinating the peripheral immunological response to injury. To date, the mechanisms responsible for signalling the presence of injury or disease to selectively activate responses in distant organs were unclear. Circulating endogenous extracellular vesicles (EVs) are increased after brain injury and have the potential to carry targeted injury signals around the body. Here, we examined the potential of EVs, isolated from rats after focal inflammatory brain lesions using IL-1β, to activate a systemic APR in recipient naïve rats, as well as the behavioural consequences of EV transfer. Focal brain lesions increased EV release, and, following isolation and transfer, the EVs were sequestered by the liver where they initiated an APR. Transfer of blood-borne EVs from brain-injured animals was also enough to suppress exploratory behaviours in recipient naïve animals. EVs derived from brain endothelial cell cultures treated with IL-1β also activated an APR and altered behaviour in recipient animals. These experiments reveal that inflammation-induced circulating EVs derived from endothelial cells are able to initiate the APR to brain injury and are sufficient to generate the associated sickness behaviours, and are the first demonstration that EVs are capable of modifying behavioural responses
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