Market conditions, default risk and credit spreads

This study empirically examine the impact of market conditions on credit spreads as motivated by recently developed structural credit risk models. Using credit default swap (CDS) spreads, we find that, in the time series, average credit spreads are decreasing in GDP growth rate, but increasing in GDP growth volatility. We document that credit spreads are lower when investor sentiment is high and when the systematic jump risk is low. In the cross section, we confirm that firm-level cash flow volatility raises credit spreads. More importantly, we demonstrate that the impact of market conditions on credit spreads is substantially affected by firm heterogeneity. During economic expansions, ceteris paribus, firms with high cash flow betas have lower credit spreads than those with low cash flow betas. This relation disappears during economic recessions, consistent with theoretical predictions. -- In diesem Arbeitspapier untersuchen wir empirisch, wie die gesamtwirtschaftlichen Bedingungen die Renditeabstände von Unternehmensanleihen, die mit einem Ausfallrisiko behaftet sind, beeinflussen. Dabei verwenden wir Spreads von Kreditausfallswaps (Credit Default Swap, CDS) als Näherungswert für Kreditspreads und stellen fest, dass die durchschnittlichen Kreditspreads im Zeitverlauf bei wirtschaftlicher Expansion niedriger und bei wirtschaftlicher Rezession höher sind. Wenn das Wirtschaftswachstum volatiler ist, führt dies ebenfalls zu höheren Kreditspreads. Wir stellen fest, dass Kreditspreads bei positiver Anlegerstimmung und geringem Risiko eines marktweiten Sprungs niedriger ausfallen. Firmenübergreifend stellen wir fest, dass ein auf Unternehmensebene volatiler Cashflow zu einer Erhöhung der Kreditspreads führt. Was noch entscheidender ist, wir zeigen, dass in Zeiten wirtschaftlicher Expansion ? bei ansonsten gleichen Bedingungen ? Unternehmen, deren Cashflow stark mit dem gesamtwirtschaftlichen Wachstum korreliert, geringere Kreditspreads aufweisen als solche mit einer schwachen Cashflow-Korrelation. Im Einklang mit den theoretischen Voraussagen verschwindet dieser Zusammenhang in Zeiten wirtschaftlicher Rezession.Credit Risk,Credit Default Swaps,Credit Spreads,Market Conditions

Structure and Function of Olfactory Sensilla on the Antennae of Soybean Aphids, Aphis glycines

Observation were made on the morphology of antennal sensilla of Aphis glycines using scanning electron microscopy. Apterae have antennal sensilla similar to those of the alatae, A group of four stout and often blunt-ended hairs appear at the tip of the antenna. A flattened sense organ (primary rhinarium) is located on the fifth antennal segment and that on the sixth segment there are four sensilla coeloconica and two sensilla placodea. They are ringed with a fringe of cuticle of which the finger-like extensions might function as a protective sieve against the entry of undesirable particles. Secondary rhinaria consist of sensilla placoidea resembling that on the fifth antennal segment, but without the elaborate fringe. Alatae differ even more markedly from apterae by possession of several to many secondary rhinaria on the flagellum. There were many secondary rhinaria on the third and the fourth, even the fifth segment in male A. glycines. The olfactory site of tested chemicals were analyzed by making use of EAG technique. It is demonstrated that primary rhinarium on the sixth antennal segment in slate Virginoparae responds to terpene derivatives (their alcohols, aldehydes and esters), but not to terpene hydrocarbons. While the rhinarium on the fifth segment responds to terpene hydrocarbons and not to terpene derivatives. Green leaf volatile and aromatic compounds were perceived by primary rhinaria on both segments, but the intensities of olfactory respones to the chemicals in each rhinarium are different. Besides the primary rhinaria on the two segments, receptor cells which responded strongly to (E)-2-hexanal and 1-hexanal were found on other sensilla, which might be the trichodea (1 µm) and the small placodea (0.8 µm) on the fifth segment. However, there was no direct electrophysiological evidence for it. Primary rhinarium on the sixth segment consists of main olfactory receptors for 3-octen-1-ol; moreover, trichodeum and small placodeum on the some segment might also contribute to the sensory response to 3-octen-1-ol. Primary rhinarium on the sixth segment was proved to be the sensory site for (E)-ß -farnesene in alate and apterous virgenoparae. Caryophyllene, which is an inhibitor of alarming pheromone, and (E)-ß-farnesene tarnesene could evoke a weak response in the secondary rhinaria on the t hird segment, and the primary rhinarium in apterous virginoparae.Originating text in Chinese.Citation: Du, Yongjun, Yan, Fushun, Tang, Jue. (1995). Structure and Function of Olfactory Sensilla on the Antennae of Soybean Aphids, Aphis glycines. Kun chong xue bao.Acta entomologica Sinica, 38(1), 1-7

Olfaction in Host Plant Selection of the Soybean Aphid Aphis glycines

Results from a behavioral study using a four-armed olfactometer (Vet et al, 1983) showed that alate and apterous virginopara of Aphis glycines were clearly attracted or arrested by volatiles from Glycine max, its secondary host plant, and Rhamnus davurica, its primary host plant. The attractiveness of G. max was greater than that of R. davurica. Chemical analysis indicated that there is some difference in the volatile profiles between these two plant species. The volatiles from two nonhost plant species Gossypium hirsutrm and Cucumis sativa, which are the most suitable host plants of another aphid A. gossypii closely related to A. glycines, were found to be neutral. However, the odors of Luffa cylindrical and Cucurbita pepo significantly repelled the alate virginopara of A. glycines. Thus, the olfactory response of A. glycines to these host and nonhost plants implies the evolutionary transition of A. glycines in host plant specificity. Blending the odors from nonhost plants Gossypium hirsutum, Luffa cylindrical and Cucurbita pepo with the attractive odor of host plant G. max blocked the attractiveness of the latter to the alate virginopara of A. glycines. It thus appeared that attractiveness of host plant to aphids can be disrupted by the presence of nonhost plant volatiles which have presumably masked the host plant odor, and the lack of attractiveness of the blended odors is caused by the change in volatile profile.Originating text in Chinese.Citation: Du, Yongjun, Yan, Fushun, Han, Xinli, Zhang, Guangxue. (1994). Olfaction in Host Plant Selection of the Soybean Aphid Aphis glycines. Kun chong xue bao. Acta entomologica Sinica, 37(4), 385-392

EPR Study of Spin Labeled Brush Polymers in Organic Solvents

Spin-labeled polylactide brush polymers were synthesized via ring-opening metathesis polymerization (ROMP), and nitroxide radicals were incorporated at three different locations of brush polymers: the end and the middle of the backbone, and the end of the side chains (periphery). Electron paramagnetic resonance (EPR) was used to quantitatively probe the macromolecular structure of brush polymers in dilute solutions. The peripheral spin-labels showed significantly higher mobility than the backbone labels, and in dimethylsulfoxide (DMSO), the backbone end labels were shown to be more mobile than the middle labels. Reduction of the nitroxide labels by a polymeric reductant revealed location-dependent reactivity of the nitroxide labels: peripheral nitroxides were much more reactive than the backbone nitroxides. In contrast, almost no difference was observed when a small molecule reductant was used. These results reveal that the dense side chains of brush polymers significantly reduce the interaction of the backbone region with external macromolecules, but allow free diffusion of small molecules

Twenty-six circulating antigens and two novel diagnostic candidate molecules identified in the serum of canines with experimental acute toxoplasmosis

List of CAg proteins identified by LC-MS/MS after IP enrichment and purification with ESA antibodies. (XLSX 27 kb

Refined Motion Compensation with Soft Laser Manipulators using Data-Driven Surrogate Models

Non-contact laser ablation, a precise thermal technique, simultaneously cuts and coagulates tissue without the insertion errors associated with rigid needles. Human organ motions, such as those in the liver, exhibit rhythmic components influenced by respiratory and cardiac cycles, making effective laser energy delivery to target lesions while compensating for tumor motion crucial. This research introduces a data-driven method to derive surrogate models of a soft manipulator. These low-dimensional models offer computational efficiency when integrated into the Model Predictive Control (MPC) framework, while still capturing the manipulator's dynamics with and without control input. Spectral Submanifolds (SSM) theory models the manipulator's autonomous dynamics, acknowledging its tendency to reach equilibrium when external forces are removed. Preliminary results show that the MPC controller using the surrogate model outperforms two other models within the same MPC framework. The data-driven MPC controller also supports a design-agnostic feature, allowing the interchangeability of different soft manipulators within the laser ablation surgery robot system

Chiral magnetic waves in strongly coupled Weyl semimetals

Propagating chiral magnetic waves (CMW) are expected to exist in chiral plasmas due to the interplay between the chiral magnetic and chiral separation effects induced by the presence of a chiral anomaly. Unfortunately, it was pointed out that, because of the effects of electric conductivity and dissipation, CMW are overdamped and therefore their signatures are unlikely to be seen in heavy-ion collision experiments and in the quark gluon plasma. Nonetheless, the chiral anomaly plays a fundamental role in Weyl semimetals and their anomalous transport properties as well. Hence, CMW could be potentially observed in topological semimetals using table-top experiments. By using a holographic model for strongly coupled Weyl semimetals, we investigate in detail the nature of CMW in presence of Coulomb interactions and axial charge relaxation and estimate whether, and in which regimes, CMW could be observed as underdamped collective excitations in topological materials.Comment: 39 pages, 11 figures, published versio