Bond funds and credit risk

We show that supply-side effects arising from the bond holdings of open-end mutual funds affect corporate credit risk. In our model, funds exposed to flow-performance relationships are reluctant to roll over bonds of companies with weak cash flow prospects fearing future outflows. This lowers rollover prices, enhancing equityholders' strategic default incentives, engendering a positive association between bond funds' presence and credit risk. Empirically, we find that in firms with weak cash flow prospects, fund holding shares increase CDS spreads, and more so when flows are more sensitive to performance. We use instrumental variables and quasi-experiments to address endogeneity concerns

Communication-Efficient Federated Learning over Capacity-Limited Wireless Networks

In this paper, a communication-efficient federated learning (FL) framework is proposed for improving the convergence rate of FL under a limited uplink capacity. The central idea of the proposed framework is to transmit the values and positions of the top-$S$ entries of a local model update for uplink transmission. A lossless encoding technique is considered for transmitting the positions of these entries, while a linear transformation followed by the Lloyd-Max scalar quantization is considered for transmitting their values. For an accurate reconstruction of the top-$S$ values, a linear minimum mean squared error method is developed based on the Bussgang decomposition. Moreover, an error feedback strategy is introduced to compensate for both compression and reconstruction errors. The convergence rate of the proposed framework is analyzed for a non-convex loss function with consideration of the compression and reconstruction errors. From the analytical result, the key parameters of the proposed framework are optimized for maximizing the convergence rate for the given capacity. Simulation results on the MNIST and CIFAR-10 datasets demonstrate that the proposed framework outperforms state-of-the-art FL frameworks in terms of classification accuracy under the limited uplink capacity

Do bilayer metasurfaces behave as a stack of decoupled single-layer metasurfaces?

Flat optics or metasurfaces have opened new frontiers in wavefront shaping and its applications. Polarization optics is one prominent area which has greatly benefited from the shape-birefringence of metasurfaces. However, flat optics comprising a single layer of meta-atoms can only perform a subset of polarization transformations, constrained by a symmetric Jones matrix. This limitation can be tackled using metasurfaces composed of bilayer meta-atoms but exhausting all possible combinations of geometries to build a bilayer metasurface library is a very daunting task. Consequently, bilayer metasurfaces have been widely treated as a cascade (product) of two decoupled single-layer metasurfaces. Here, we test the validity of this assumption by considering a metasurface made of TiO2 on fused silica substrate at a design wavelength of 532 nm. We explore regions in the design space where the coupling between the top and bottom layers can be neglected, i.e., producing a far-field response which approximates that of two decoupled single-layer metasurfaces. We complement this picture with the near-field analysis to explore the underlying physics in regions where both layers are strongly coupled. Our analysis is general and it allows the designer to efficiently build a multi-layer metasurface, either in transmission or reflection, by only running one full-wave simulation for a single-layer metasurface.Comment: 26 pages, 12 figure

Environmental implications of a sandwich structure of a glass fiber-reinforced polymer ship

This study presents the findings related to the selection of composite structures for materials with respect to the effectiveness of their lightweight design and environmental impact during the raw material manufacturing phases. The primary raw materials considered were glass fiber, PVC for the core, and polyester resin. In addition, using the same design conditions, such as bottom load, impregnation rate, and production method, a reverse engineering approach was applied to transform the sandwich structure into a single laminate structure, allowing for a comparative quantitative analysis of the reduction in lightweight effectiveness. The results revealed that the sandwich structure was approximately 42.44% lighter than that of the reverse-engineered single-skin laminate structure. A life cycle evaluation was also conducted, and the raw materials required for hull construction were analyzed with SimaPro 9.0 as the LCA tool software, Ecoinvent 3 for inventory analysis, and the ReCiPe 2016 method for environmental impact analysis. PVC foam and polyester resin were identified as highly hazardous for both human and environmental health, whereas fiberglass exhibited the lowest emissions among the materials considered. Furthermore, the sandwich structure offered greater environmental advantages across all damage endpoints than the single-skin laminates. This finding highlights the potential of sandwich structures as a more sustainable option. In practical terms, enhancing the bending strength of the core material in sandwich structures can reduce the thickness of the outer and inner skin members, thereby reducing the weight of ships and significantly reducing potential health risks to human worker health, harm to the ecosystem, and resource demands

Successful Management of a Rare Case of Stent Fracture and Subsequent Migration of the Fractured Stent Segment Into the Ascending Aorta in In-Stent Restenotic Lesions of a Saphenous Vein Graft

Stent fracture is a complication following implantation of drug eluting stents and is recognized as one of the risk factors for in-stent restenosis. We present the first case of successfully managing a stent fracture and subsequent migration of the fractured stent into the ascending aorta that occurred during repeat revascularization for in-stent restenosis of an ostium of saphenous vein graft after implantation of a zotarolimus-eluting stent. Although the fractured stent segment had migrated into the ascending aorta with a pulled balloon catheter, it was successfully repositioned in the saphenous vein graft using an inflated balloon catheter. Then, the fractured stent segment was successfully connected to the residual segment of the zotarolimus-eluting stent by covering it with an additional sirolimuseluting stent

Late Stent Thrombosis After Drug-Eluting Stent Implantation: A Rare Case of Accelerated Neo-Atherosclerosis and Early Manifestation of Neointimal Rupture

An 80-year old woman suffered from sudden onset of chest pain and dyspnea, and visited the emergency room. She received stent implantation with a biolimus A9-eluting stent (Nobori® 3.0×24 mm) at a the mid-portion of the left anterior descending artery 5 months prior to admission. The emergency 5-month follow-up angiogram was performed under the impression of late stent thrombosis. The follow-up angiogram showed subtotal occlusion at the mid-portion of the left anterior descending artery, which was the same segment of previous stent implantation 5 months ago. Immediately after thrombus aspiration with the thrombus aspiration catheter, the optical coherence tomography showed layered appearance of neointimal hyperplasia and neointimal rupture within the previously stented segment. Thus, neointimal rupture within accelerated growth of neointimal tissue was observed within a relatively shorter period (i.e., about 5 months) after stent implantation

Clinical and Echocardiographic Findings of Newly Diagnosed Acute Decompensated Heart Failure in Elderly Patients

PURPOSE: Elderly patients (pts) (EPs; ≥ 65 years old) with newly diagnosed-acute decompensated heart failure (ND-ADHF) have not yet been studied. The aim of the present study was to investigate clinical characteristics, including echocardiographic findings and prognosis, for EPs with ND-ADHF and to compare those with non-elderly pts (NEPs). MATERIALS AND METHODS: We retrospectively investigated 256 pts (144 males, 63.0 ± 14.8 years old) who were admitted to our hospital between January 2005 and March 2009 with ND-ADHF. Clinical characteristics and echocardiographic parameters were analyzed in EPs (n = 135, 58 males) and NEPs (n = 121, 86 males). RESULTS: In intergroup comparison, female gender, diabetes mellitus, previous stroke and hypertension were more common in EPs. Body mass index (22.3 ± 4.5 vs. 24.0 ± 4.4 kg/m(2)), estimated glomerular filtration rate (54.8 ± 24.3 vs. 69.2 ± 30.7 mL/min/m(2)), C-reactive protein (28.5 ± 46.9 vs. 7.6 ± 11.6 mg/dL), hemoglobin (12.3 ± 2.1 vs. 13.6 ± 2.3 g/dL) and N-terminal pro-brain natriuretic peptide level (10,538.2 ± 10,942.3 vs. 6,771.0 ± 8,964.7 pg/mL) were significantly different (p < 0.05 for all). Early mitral inflow velocity to early diastolic mitral annular velocity (E/E') was significantly higher in EPs than in NEPs (21.2 ± 9.4 vs. 18.0 ± 8.9, p < 0.05). During follow-up (44.7 ± 14.5 months), there were no significant differences in in-hospital mortality, re-hospitalization and cardiovascular mortality between EPs and NEPs (p = NS for all). CONCLUSION: EPs with ND-ADHF have different clinical characteristics and higher LV filling pressure when compared with NEPs. However, the clinical outcomes for NEPs with ND-ADHF are not necessarily more favorable than those for EPs.ope

Nlrp3, Csf3, and Edn1 in Macrophage Response to Saturated Fatty Acids and Modified Low-Density Lipoprotein

Background and Objectives: The relationship between metabolic stress, inflammation, and cardiovascular disease is being studied steadily. The aim of this study was to evaluate the effect of palmitate (PA) and minimally modified low-density lipoprotein (mmLDL) on macrophages and to identify the associated pathways. Methods: J774 macrophages were incubated with PA or mmLDL and lipopolysaccharide (LPS). Secretion of inflammatory chemokines and the expression of corresponding genes were determined. The phosphorylation of extracellular signal-regulated kinase (ERK) mitogen-activated protein kinase was also assessed. RNA sequencing of macrophages was performed to identify the genes regulated by PA or mmLDL. Some of the genes regulated by the 2 agents were validated by knocking down the cells using small interfering RNA. Results: PA or mmLDL promoted the secretion of interleukin (IL)-6 and IL-1 beta in LPS-stimulated macrophages, and this was accompanied by higher phosphorylation of ERK. RNA sequencing revealed dozens of genes that were regulated in this process, such as Csf3and Edn1, which were affected by PA and mmLDL, respectively. These agents also increased NIrp3 expression. The effect of Csf3 or Edn1 silencing on inflammation was modest, whereas toll-like receptor (TLR) 4 inhibition reduced a large proportion of macrophage activation. Conclusions: We demonstrated that the proinflammatory milieu with high levels of PA or mmLDL promoted macrophage activation and the expression of associated genes such as NIrp3, 613, and Edn1. Although the TLR4 pathway appeared to be most relevant, additional role of other genes in this process provided insights regarding the potential targets for intervention.11Nsciescopu