Credit cycles and macro fundamentals

We study the relation between the credit cycle and macro economic fundamentals in an intensity based framework. Using rating transition and default data of U.S. corporates from Standard and Poor’s over the period 1980–2005 we directly estimate the credit cycle from the micro rating data. We relate this cycle to the business cycle, bank lending conditions, and financial market variables. In line with earlier studies, these variables appear to explain part of the credit cycle. As our main contribution, we test for the correct dynamic specification of these models. In all cases, the hypothesis of correct dynamic specification is strongly rejected. Moreover, accounting for dynamic mis-specification, many of the variables thought to explain the credit cycle, turn out to be insignificant. The main exceptions are GDP growth, and to some extent stock returns and stock return volatilities. Their economic significance appears low, however. This raises the puzzle of what macro-economic fundamentals explain default and rating dynamics. JEL Classification: G11, G2

Credit Cycles and Macro Fundamentals

We study the relation between the credit cycle and macro economic fundamentals in an intensity based framework. Using rating transition and default data of U.S. corporates from Standard and Poor’s over the period 1980–2005 we directly estimate the credit cycle from the micro rating data. We relate this cycle to the business cycle, bank lending conditions, and financial market variables. In line with earlier studies, these variables appear to explain part of the credit cycle. As our main contribution, we test for the correct dynamic specification of these models. In all cases, the hypothesis of correct dynamic specification is strongly rejected. Moreover, accounting for dynamic mis-specification, many of the variables thought to explain the credit cycle, turn out to be insignificant. The main exceptions are GDP growth, and to some extent stock returns and stock return volatilities. Their economic significance appears low, however. This raises the puzzle of what macro-economic fundamentals explain default and rating dynamics.Credit Cycles, Business Cycles, Bank Lending Conditions, Unobserved Component Models, Intensity Models, Monte Carlo Likelihood

Strength, muscle quality and functional capacity in liver transplanted familial amyloidotic polineuropathy patients

Liver transplantation is the unique treatment for several end-stage diseases. Familial Amiloidotic Polineuropathy (FAP) is a neurodegenerative disease related with systemic deposition of amyloidal fiber mainly on peripheral nervous system, clinically translated by an autonomous sensitive-motor neuropathy with severe functional limitations in some cases. The unique treatment for FAP disease is a liver transplant with a very aggressive medication to muscle metabolism and force production. To our knowledge there are no quantitative characterizations of body composition, strength or functional capacity in this population

Baseflow and water resilience variability in two water management units in southeastern Brazil

Changes in climate and water demand in densely populated regions increasingly affect hydrological systems, and, in turn, impact socioeconomic conditions. In this case study, we identify how the hydrogeological frameworks of two water resource management units, Tietê-Jacaré (TJ) and Piracicaba-Capivari-Jundiaí (PCJ) in Sao Paulo state (Brazil), control the baseflow processes and resilience in the face of streamflow fluctuations in response to anthropogenic activities and climate variation. The results reveal between 40% and 75% contributions of baseflow to total streamflow in basins overlying crystalline and sedimentary aquifers. The basins in PCJ which mostly overly crystalline aquifers, have shorter water residence times and greater dependence on surface water. Therefore, streamflow in the PCJ basins is vulnerable during the drought period and the management model affected the water resilience of the basins (transfer of water to Cantareira System). The TJ basins have greater streamflow contributions from aquifer discharge linked to the presence of important sedimentary aquifers, which improves resilience under changing rainfall patterns, these basins present a more stable situation of resilience. Ultimately, the two management units require different planning strategies with adaptive and dynamic actions to mitigate the social, economic, and environmental effects caused by the variability and reduction of water sources

Tracing the envelopes around embedded low-mass young stellar objects with HCO+ and millimeter-continuum observations

Interferometer observations of millimeter-continuum (OVRO) and single-dish observations of HCO+ and H13CO+ J=1-0, 3-2, and 4-3 (JCMT, IRAM 30m) are presented of nine embedded low-mass young stellar objects (YSOs) in Taurus. All nine objects are detected at 3.4 and 2.7 mm, with fluxes of 4-200 mJy, and consist of unresolved (<3 arcsec) point sources, plus, toward about half of the objects, an extended envelope. The point sources likely are circumstellar disks, showing that these are established early in the embedded phase. Literature values of 1.1 mm continuum emission are used to trace the envelopes, carrying 0.001-0.26 M(sol). In HCO+, the 1-0 lines trace the surrounding clouds, while the 3-2 and 4-3 are concentrated toward the sources with intensities well correlated with the envelope flux. An HCO+/H2 abundance of 1.2e-8 is derived. The HCO+ line strengths and envelope fluxes can be fit simultaneously with the simple collapse model of Shu (1977), and related density power laws with slopes p=1-3. As an indicator of the relative evolutionary phase of a YSO, the ratio of HCO+ 3-2 line intensity over bolometric luminosity is proposed, which is roughly proportional to the current ratio of envelope over stellar mass. It is concluded that HCO+ 3-2 and 4-3 are excellent tracers of the early embedded phase of star formation.Comment: 45 pages, 10 figures, ApJ/AASLaTeX. To be published in The Astrophysical Journa

Automatic 3D aortic annulus sizing by computed tomography in the planning of transcatheter aortic valve implantation

Background: Accurate imaging assessment of aortic annulus (AoA) dimension is paramount to decide on the correct transcatheter heart valve (THV) size for patients undergoing transcatheter aortic valve implantation (TAVI). We evaluated the feasibility and accuracy of a novel automatic framework for multi detector row computed tomography (MDCT)-based TAVI planning. Methods: Among 122 consecutive patients undergoing TAVI and retrospectively reviewed for this study, 104 patients with preoperative MDCT of sufficient quality were enrolled and analyzed with the proposed software. Fully automatic (FA) and semi-automatic (SA) AoA measurements were compared to manual measurements, with both automated and manual-based interobserver variability (IOV) being assessed. Finally, the effect of these measures on hypothetically selected THV size was evaluated against the implanted size, as well as with respect to manually-derived sizes. Results: FA analysis was feasible in 92.3% of the cases, increasing to 100% if using the SA approach. Automatically-extracted measurements showed excellent agreement with manually-derived ones, with small biases and narrow limits of agreement, and comparable to the interobserver agreement. The SA approach presented a statistically lower IOV than manual analysis, showing the potential to reduce interobserver sizing disagreements. Moreover, the automated approaches displayed close agreement with the implanted sizes, similar to the ones obtained by the experts. Conclusion: The proposed automatic framework provides an accurate and robust tool for AoA measurements and THV sizing in patients undergoing TAVI.FCT - Fundação para a Ciência e a Tecnologia, Portugal, and the European Social Found, European Union, through the Programa Operacional Capital Humano (POCH) in the scope of the PhD grants SFRH/BD/93443/2013 (S. Queirós) and SFRH/BD/95438/2013 (P. Morais), and the project ‘PersonalizedNOS (01-0145-FEDER-000013)’ co-funded by Programa Operacional Regional do Norte (QREN), through Fundo Europeu de Desenvolvimento Regional (FEDER)info:eu-repo/semantics/publishedVersio

Fast left ventricle tracking in CMR images using localized anatomical affine optical flow

"Progress in Biomedical Optics and Imaging, vol. 16, nr. 41"In daily cardiology practice, assessment of left ventricular (LV) global function using non-invasive imaging remains central for the diagnosis and follow-up of patients with cardiovascular diseases. Despite the different methodologies currently accessible for LV segmentation in cardiac magnetic resonance (CMR) images, a fast and complete LV delineation is still limitedly available for routine use. In this study, a localized anatomically constrained affine optical flow method is proposed for fast and automatic LV tracking throughout the full cardiac cycle in short-axis CMR images. Starting from an automatically delineated LV in the end-diastolic frame, the endocardial and epicardial boundaries are propagated by estimating the motion between adjacent cardiac phases using optical flow. In order to reduce the computational burden, the motion is only estimated in an anatomical region of interest around the tracked boundaries and subsequently integrated into a local affine motion model. Such localized estimation enables to capture complex motion patterns, while still being spatially consistent. The method was validated on 45 CMR datasets taken from the 2009 MICCAI LV segmentation challenge. The proposed approach proved to be robust and efficient, with an average distance error of 2.1 mm and a correlation with reference ejection fraction of 0.98 (1.9 ± 4.5%). Moreover, it showed to be fast, taking 5 seconds for the tracking of a full 4D dataset (30 ms per image). Overall, a novel fast, robust and accurate LV tracking methodology was proposed, enabling accurate assessment of relevant global function cardiac indices, such as volumes and ejection fraction.The authors acknowledge funding support from FCT - Fundação para a Ciência e Tecnologia, Portugal, in the scope of the PhD grant SFRH/BD/93443/2013 and the project EXPL/BBB-BMD/2473/2013. D. Barbosa would also like to acknowledge the kind support of the Fundação Luso-Americana para o Desenvolvimento (FLAD), which has funded the travel costs for participation at SPIE Medical Imaging 2015.info:eu-repo/semantics/publishedVersio

Comparison of body fat content and distribution of familial amyloidotic polyneuropathy patients versus healthy subjects

The deposition of amyloid fibers at the peripheral nervous system can induce motor neuropathy in Familial Amiloidotic Polyneuropethy (FAP) patients. This produces progressive reductions in functional capacity. The only treatment for FAP is a liver transplant, followed by aggressive medication that can affect patients' metabolism. To our knowledge, there are no data on body fat distribution or comparison between healthy and FAP subjects, which may be important for clinical assessment and management of this disease

The acinetobacter baumannii SOS gene ddrR is crucial for prophage maintenance and induction

Acinetobacter baumannii, considered a number one priority pathogen by WHO, is threatening hospitals due to its high ability to acquire antibiotic resistance. We have recently shown that mobile elements, such as prophages, are highly prevalent and encode several fitness/virulence-related genes, suggesting that they may serve as vectors for the spread of virulence. Here, we want to understand how stress factors influence the prophage behavior and disclose the role of the unique SOS response system, umuDAb and ddrR, in prophage induction. First, the A. baumannii ATCC 17978 strain was subjected to different sub-mic concentrations of mitomycin C (MMC), H O , and ciprofloxacin (cip), followed by incubation, RNA extraction and qRT-PCR analysis. After verifying the prophage behavior under these stress conditions, a ddrR knockout mutant was engineered using CRISPR-Cas9 to assess its influence on prophage expression. As expected, all conditions triggered an SOS response in the type strain as well as prophage induction, as both the ddrR and umuDAb genes, and the cro and capsid genes were overexpressed. Different levels of induction were observed between the conditions tested. For example, prophage induction was lower when challenged with cip than with MMC. In terms of growth curves, we observed that the ddrR mutant grew at faster than the type strain. Curiously, when challenged with MMC, the type strain showed significantly decreased CFUs in contrast to the ddrR mutant strain. Our findings show that each stress condition leads to different levels of prophage responses and that some can increase the fitness/virulence expression without detrimental effects on the host. The SOS gene ddrR is important for prophage induction and, consequently, its absence contributes to the bacterial robustness during growth. In conclusion, it is important to understand how prophages are affected by host genes under different stresses to improve antimicrobial efficacy.info:eu-repo/semantics/publishedVersio