In recent years, the non-covalent interactions between chalcogen centers have aroused substantial research interest because of their potential applications in organocatalysis, materials science, drug ...design, biological systems, crystal engineering, and molecular recognition. However, studies on π-hole-type chalcogen∙∙∙chalcogen interactions are scarcely reported in the literature. Herein, the π-hole-type intermolecular chalcogen∙∙∙chalcogen interactions in the model complexes formed between XOsub.2 (X = S, Se, Te) and CHsub.3YCHsub.3 (Y = O, S, Se, Te) were systematically studied by using quantum chemical computations. The model complexes are stabilized via one primary X∙∙∙Y chalcogen bond (ChB) and the secondary C−H∙∙∙O hydrogen bonds. The binding energies of the studied complexes are in the range of −21.6~−60.4 kJ/mol. The X∙∙∙Y distances are significantly smaller than the sum of the van der Waals radii of the corresponding two atoms. The X∙∙∙Y ChBs in all the studied complexes except for the SOsub.2∙∙∙CHsub.3OCHsub.3 complex are strong in strength and display a partial covalent character revealed by conducting the quantum theory of atoms in molecules (QTAIM), a non-covalent interaction plot (NCIplot), and natural bond orbital (NBO) analyses. The symmetry-adapted perturbation theory (SAPT) analysis discloses that the X∙∙∙Y ChBs are primarily dominated by the electrostatic component.
We examine the pricing difference of Green Bonds (GB) and conventional bonds (CBs) in capital markets worldwide. Credit spread is used to observe whether investors would like to pay a premium for GBs ...over CBs. This study uses panel data regression with hybrid model to analyse daily observations over the period 2016 to 2017. We employ Option-Adjusted spread (OAS) to measure the credit spreads of bonds while controlling for bond specific, macroeconomic and global factors that influence the spread. With the hybrid model used in the panel data analysis, we were able to capture the fixed-effects of variables in a random effect model. We find that GBs are traded at a premium of 63 basis points (BPS), compared with a comparable corporate bond issue. We find that the green label provides issuers an incentive to raise funds through issuing GBs while providing investors an opportunity to diversify their investments returns. Our findings provide several implications to the major stakeholders driving the GB market to scale up the market to finance the required level of global green investment needs. We stress an urgent need to support the growth of the GB market to achieve sustainable development through mitigating climate change challenges.
Abbreviation GB: Green Bond; CB: Conventional Bond; YS: Yield Spread; BPS: Basis Points; OAS: Option-Adjusted Spread; PCSE: Panels Corrected Standard Errors; CPI: Consumer Price Index; GBPs: Green Bond Principles; CBS: Climate Bond Standard
Purpose
investigate shear bond strength of different bulk-fill composite systems to the dentin with or without preheating.
Material and methods
This in vitro study was performed on sixty sounds ...extracted periodontally affected human molars. The enamel of the occlusal surfaces was removed to expose the superficial dentin. The samples with flat occlusal dentin surfaces were randomly divided into two groups of thirty teeth each (n = 30) according to the type of restoration material used, each group is then subdivided into two subgroups (A and B) each (15 specimens), corresponding to the modified technique of application with or without preheating using transparent polymer tubes 4 × 4mm.
Group I: X-tra fill bulk fill composite and Group II: Tetric®N-Ceram Nano hybrid Bulk fill composite (compules). All specimens were subjected to thermocycling and were tested in shear mode. The debonded surfaces of the samples were inspected to determine the mode of failure for each specimen. All data was collected, tabulated, and statistically analyzed.
Results
There were no significant differences between the shear bond strength of two studied groups (X-tra fill and Tetric N-ceram bulk-fill) and their subgroups (A and B), considering with preheating modality recorded slightly higher insignificant statistically mean values in MPa. The most observed mode of failures in composite resin were of mixed mode. The type of composite resin material has no statistically significant difference effect of shear bond strength. On the other hand, it was found that there is a significant effect of the thermal treatment modality on the bond strength regardless the type of composite material used.
Conclusion
within the limits of the present study, the preheated bulk fill composite resin had a superior significant bond strength to dentin compared to unheated one.
We examine co-movement between the green bond and financial markets, finding that the green bond market couples with corporate and treasury bond markets and weakly co-moves with stock and energy ...commodity markets. We also find that green bonds have negligible diversification benefits for investors in corporate and treasury markets, whereas diversification benefits are sizeable for investors in stock and energy markets. We further confirm that green bonds are affected by substantial price spillovers from corporate and treasury fixed-income markets and that large price swings in stock and energy markets have a negligible impact on green bond prices.
•We study co-movement between the green bond and financial markets.•The green bond market couples with corporate and treasury bond markets.•The green bond market weakly co-moves with stock and energy commodity markets.•Diversification benefits of green bonds are sizeable for stock and energy markets.•Green bonds are affected by price spillovers from fixed-income markets.
The Illiquidity of Corporate Bonds BAO, JACK; PAN, JUN; WANG, JIANG
The Journal of finance (New York),
June 2011, Volume:
66, Issue:
3
Journal Article
Peer reviewed
Open access
This paper examines the illiquidity of corporate bonds and its asset-pricing implications. Using transactions data from 2003 to 2009, we show that the illiquidity in corporate bonds is substantial, ...significantly greater than what can be explained by bid-ask spreads. We establish a strong link between bond illiquidity and bond prices. In aggregate, changes in market-level illiquidity explain a substantial part of the time variation in yield spreads of high-rated (AAA through A) bonds, overshadowing the credit risk component. In the cross-section, the bond-level illiquidity measure explains individual bond yield spreads with large economic significance.
Using a complete record of U.S. over-the-counter (OTC) secondary trades in corporate bonds, we estimate average transaction costs as a function of trade size for each bond that traded more than nine ...times between January 2003 and January 2005. We find that transaction costs decrease significantly with trade size. Highly rated bonds, recently issued bonds, and bonds close to maturity have lower transaction costs than do other bonds. Costs are lower for bonds with transparent trade prices, and they drop when the TRACE system starts to publicly disseminate their prices. The results suggest that public traders benefit significantly from price transparency.
InThe New Masters of Capital, Timothy J. Sinclair examines a key aspect of the global economy-the rating agencies. In the global economy, trust is formalized in the daily operations of such firms as ...Moody's and Standard & Poor's, which continuously monitor the financial health of bond-issuers ranging from private corporations to local and national governments. Their judgments affect unimaginably large sums, approximately $30 trillion in outstanding debt issues, according to a recent Moody's estimate. The difference between an AA and a BB rating may cost millions of dollars in interest payments or determine if a corporation or government can even issue bonds.
Without bond rating agencies, there would be no standard means to compare risks in the global economy, and international investment would be problematic. Most observers assume that the agencies are neutral and scientific, and that they interpret their role in narrowly economic terms. But these agencies, by their nature, wield extraordinary power and exert massive influence over public policy. Sinclair offers a highly accessible account of these institutions, their origins, and the rating processes they use to judge creditworthiness. Illustrated with a wide range of cases, this book offers a fresh assessment of the role of an often-overlooked institution in the dynamics of modern global capitalism.
Motivated by the lack of research on price efficiency dynamics of green bonds and the impact of the COVID-19 on the pricing of fixed-income securities, this study investigates the comparative ...efficiency of green and conventional bond markets pre- and during the COVID-19 pandemic applying asymmetric multifractal analysis. Specifically, the multifractal scaling behaviour is examined separately during upward and downward trends in bond markets using the asymmetric multifractal detrended fluctuation analysis (A-MF-DFA) approach. The empirical findings confirm the presence of asymmetric multifractality in the green and traditional bond markets. Not surprisingly, inefficiency in both bond markets significantly escalated during the COVID-19 outbreak. Furthermore, our results indicate a higher level of efficiency of the conventional bond market over the full sample period. However, the green bond market is more efficient during a black swan event, such as the COVID-19 global pandemic, showing the potential of green bonds to become an effective diversifier for investors in traditional assets in times of extreme market turmoil. The results of the study can have important implications for investors and policymakers.
•Comparative efficiency of green and conventional bonds pre- and during COVID-19.•Asymmetric multifractal detrended fluctuation analysis method is applied.•Inefficiency in both bond markets significantly escalated during the COVID-19.•Higher efficiency of the conventional bond market is observed pre-COVID-19.•The green bond market is more efficient during the COVID-19 global pandemic.
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