The effect of credit rating discontinuity on firms’ capital structure

This dissertation compares rated and formerly rated firms regarding their capital structure. Using a panel dataset from 1991 to 2014, I estimate the effect of credit rating discontinuity on firms’ debt-to-equity issuance, leverage, net debt issuance, and cash holdings as proxies for their capital structure decisions. I use a set of OLS regressions with established control variables and employ time, firm, and industry fixed effects. The results suggest that we do observe rating discontinuity within this sample and that firms experiencing periods without S&P rating and continuously rated firms present differences in capital structure. Firms with rating discontinuity show lower debt-to-equity issuance, lower leverage, less net debt issuances, and higher cash holdings than continuously rated firms. These effects strengthen over time. However, this work cannot finally prove the existence of rating discontinuity. Without assuming that ratings from other CRAs are perfect substitutes for S&P ratings, there is still the possibility of other aspects, like issuer shopping, causing those differences in capital structure. Further, the findings suggest a small reputation effect on net debt issuance and leverage levels. The results are robust to changes in leverage definitions and the addition of rating and investment grade information to the models.A presente dissertação tenciona comparar empresas com e sem classificações de crédito com à sua estrutura de capital. Este estudo é realizado com dados, que incluem o período entre 1991 e 2014. Estimo o efeito da descontinuidade da classificação de crédito sobre a emissão de dívida em relação ao capital próprio, a alavancagem, a emissão de dívida e a disponibilidade de tesouraria. Utilizo um conjunto de regressões MQO com variáveis de controle e uso efeitos fixos de tempo, empresa e setor. Os resultados sugerem a presença da descontinuidade da classificação e que as empresas que passam por períodos sem classificação da S&P têm diferenças na estrutura de capital. As empresas com descontinuidade de classificação apresentam menor emissão de dívida em relação ao patrimônio líquido, menor alavancagem, menor emissão de dívida líquida e uma maior disponibilidade de tesouraria do que as empresas com classificação contínua. Esses efeitos se fortalecem com o tempo. Entretanto, este trabalho não pode finalmente provar a existência da descontinuidade da classificação. Sem presumir que as classificações de outras CRAs sejam substitutos perfeitos para as classificações da S&P, ainda existe a possibilidade de, por exemplo, o efeito de compras como causa dessas diferenças na estrutura de capital. Além disso, os resultados sugerem um pequeno efeito da reputação sobre a emissão de dívida líquida e os níveis de alavancagem. Os resultados são robustos em relação às mudanças nas definições de alavancagem e à adição de informações de classificação e grau de investimento aos modelos

Ventricular tachycardia (VT) storm after cryoballoon-based pulmonary vein isolation

Objective: Unusual clinical course. Background: Following catheter ablation of atrial fibrillation, increased incidence of ventricular arrhythmia has been observed. We report a case of sustained ventricular arrhythmia in a patient who underwent cryoballoon-based pulmonary vein isolation for symptomatic persistent atrial fibrillation. Case Report: A 57-year-old patient with dilated cardiomyopathy underwent CB-based pulmonary vein isolation for symptomatic persistent AF. On the day following an uneventful procedure, the patient for the first time experienced a sustained ventricular tachycardia that exacerbated into VT storm. Each arrhythmia was terminated by the ICD that had been implanted for primary prevention. Antiarrhythmic treatment with amiodarone was initiated immediately. The patient remained free from sustained ventricular arrhythmia during follow-up. Conclusions: After pulmonary vein isolation, physicians should be vigilant for ventricular arrhythmia. The influence of atrial autonomic innervation on ventricular electrophysiology is largely unknown

Оптимізація паралельного ітераційного процесу для лінійних систем з розрідженими матрицями

Розглядається один із підходів до побудови передобумовлювача для методу спряжених градієнтів розв'язування СЛАР з розрідженими матрицями нерегулярної структури. Запропоновано та досліджено передобумовлювачі на основі методу паралельних перерізів.Рассматривается один из подходов к построению предобуславливателя для метода сопряженных градиентов решения СЛАУ с разреженными матрицами нерегулярной структуры. Предложены и исследованы предобуславливатели на основе метода параллельных сечений.Considered is one of approaches for construction a preconditioner for method of conjunctive gradients for solution SLAE with sparse matrices of irregular structure. Preconditioners, which are based on method of parallel section, is proposed and investigated

Listen to Your Heart: Evaluation of the Cardiologic Ecosystem

Modern implantable cardiologic devices communicate via radio frequency techniques and nearby gateways to a backend server on the internet. Those implanted devices, gateways, and servers form an ecosystem of proprietary hardware and protocols that process sensitive medical data and is often vital for patients’ health. This paper analyzes the security of this Ecosystem, from technical gateway aspects, via the programmer, to configure the implanted device, up to the processing of personal medical data from large cardiological device producers. Based on a real-world attacker model, we evaluated different devices and found several severe vulnerabilities. Furthermore, we could purchase a fully functional programmer for implantable cardiological devices, allowing us to re-program such devices or even induce electric shocks on untampered implanted devices. Additionally, we sent several Art. 15 and Art. 20 GDPR inquiries to manufacturers of implantable cardiologic devices, revealing non-conforming processes and a lack of awareness about patients’ rights and companies’ obligations. This, and the fact that many vulnerabilities are still to be found after many vulnerability disclosures in recent years, present a worrying security state of the whole ecosystem

On the problem of supersonic gas flow in two-dimensional channel with the oscillating upper wall

In the present paper we solve the problem of supersonic gas flow in two-dimensional channel with the moving upper wall making oscillations according to the harmonic law. In order to get a numerical solution for gas dynamics equations we have implemented a difference scheme with space and time approximation of the first order and one with space approximation of the second order. Depending on a type of harmonic law and initial gas inflow conditions, the peculiarities of angle-shock wave propagation in moving curvilinear domains have been investigated. It has been determined that the increase of oscillation amplitude causes the increase of shock wave intensity. It has been shown that under particular oscillation amplitude the moving wall has practically no effect on the flow within the domain

Growth Hormone Research Society perspective on the development of long-acting growth hormone preparations

Objective The Growth Hormone (GH) Research Society (GRS) convened a workshop to address important issues regarding trial design, efficacy, and safety of long-acting growth hormone preparations (LAGH). Participants A closed meeting of 55 international scientists with expertise in GH, including pediatric and adult endocrinologists, basic scientists, regulatory scientists, and participants from the pharmaceutical industry. Evidence Current literature was reviewed for gaps in knowledge. Expert opinion was used to suggest studies required to address potential safety and efficacy issues. Consensus process Following plenary presentations summarizing the literature, breakout groups discussed questions framed by the planning committee. Attendees reconvened after each breakout session to share group reports. A writing team compiled the breakout session reports into a draft document that was discussed and revised in an open forum on the concluding day. This was edited further and then circulated to attendees from academic institutions for review after the meeting. Participants from pharmaceutical companies did not participate in the planning, writing, or in the discussions and text revision on the final day of the workshop. Scientists from industry and regulatory agencies reviewed the manuscript to identify any factual errors. Conclusions LAGH compounds may represent an advance over daily GH injections because of increased convenience and differing phamacodynamic properties, providing the potential for improved adherence and outcomes. Better methods to assess adherence must be developed and validated. Long-term surveillance registries that include assessment of efficacy, cost-benefit, disease burden, quality of life, and safety are essential for understanding the impact of sustained exposure to LAGH preparations

Synaptic elements for GABAergic feed-forward signaling between HII horizontal cells and blue cone bipolar cells are enriched beneath primate S-cones.

The functional roles and synaptic features of horizontal cells in the mammalian retina are still controversial. Evidence exists for feedback signaling from horizontal cells to cones and feed-forward signaling from horizontal cells to bipolar cells, but the details of the latter remain elusive. Here, immunohistochemistry and confocal microscopy were used to analyze the expression patterns of the SNARE protein syntaxin-4, the GABA receptor subunits α1 and ρ, and the cation-chloride cotransporters NKCC and KCC2 in the outer plexiform layer of primate retina. In macaque retina, as observed previously in other species, syntaxin-4 was expressed on dendrites and axon terminals of horizontal cells at cone pedicles and rod spherules. At cones, syntaxin-4 appeared densely clustered in two bands, at horizontal cell dendritic tips and at the level of desmosome-like junctions. Interestingly, in the lower band where horizontal cells may synapse directly onto bipolar cells, syntaxin-4 was highly enriched beneath short-wavelength sensitive (S) cones and colocalized with calbindin, a marker for HII horizontal cells. The enrichment at S-cones was not observed in either mouse or ground squirrel. Furthermore, high amounts of both GABA receptor and cation-chloride cotransporter subunits were found beneath primate S-cones. Finally, while syntaxin-4 was expressed by both HI and HII horizontal cell types, the intense clustering and colocalization with calbindin at S-cones indicated an enhanced expression in HII cells. Taken together, GABA receptors beneath cone pedicles, chloride transporters, and syntaxin-4 are putative constituents of a synaptic set of proteins which would be required for a GABA-mediated feed-forward pathway via horizontal cells carrying signals directly from cones to bipolar cells