Structure Puzzle Research Articles

The Effects of Reversible Investment on Capital Structure and Credit Risks

We propose a structural model with an optimal switching of diffusion regimes that integrates a wide range of investment reversibility. The default boundary and switching thresholds are endogenously determined, and they enable us to comprehend the interrelated problems of the investment decision, capital structure, and credit risks. We examine not only the under/overinvestment but also the under/overdisinvestment. The leverage ratio decreases when the firm has an option to invest in a reversible project, which can alleviate the capital structure puzzle. Furthermore, the model significantly reduces the wide dispersion of yield spreads depending on the credit grade of bonds.

Bond Market Demand and Capital Structure Variation

This article investigates whether firms vary the debt side of their capital structure based on changes in investor demand for bonds. Examining asset flows into various asset classes over the last 30 years reveals that companies respond to recent increases in demand for bonds from investors by altering their capital structure toward greater use of debt. Firms are more likely to issue debt when demand for bonds rises, and their use of debt increases (decreases) in periods when demand for bonds is high (low) compared with periods when demand is not significantly changed. Firms use more (less) debt when spreads between corporate yields and Treasury rates are low (high), consistent with efforts by managers to adjust their debt issuances based on relative debt costs. These results hold after controlling for seasonality, firm effects, and macroeconomic conditions. These findings suggest that investor demand for debt needs to be taken into account when examining the capital structure puzzle. <b>TOPICS:</b>Fixed income and structured finance, volatility measures

Marking the Centennial of the Discovery of Alpha Silver Iodide

In 2014, present-day scientists had the opportunity of marking the centennial of a discovery that triggered the development of a new field of research, which is now called Solid State Ionics.In their 1914 paper, Carl Tubandt and Erich Lorenz reported on the extraordinary properties of the alpha phase of silver iodide. Although α-AgI was a crystalline material, it resembled a molten salt with regard to the liquid-like value and weak temperature dependence of its ionic conductivity. With their transference measurements, Tubandt and Lorenz proved that the electric current in α-AgI was completely carried by the silver ions, while the iodide ions formed a rigid lattice. Up to the present day, α-AgI has been considered the fast ion conductor par excellence.In the mid-1930s, L.W. Strock was the first to use x-ray diffraction to investigate the crystal structure of α-AgI. The anion sublattice was found to be body centered cubic, but the arrangement of the silver ions remained a puzzling question. On the one hand, Strock could assign a large number of possible crystallographic sites to them. On the other hand, the state of the silver ions appeared to be rather ‘quasi-molten’ or ‘liquid-like’. This structural puzzle was resolved in 1977, when Cava, Reidinger and Wuensch used the results of a single-crystal neutron-diffraction experiment to construct contour plots for the probability density of the silver ions in α-AgI, which turned out to have broad maxima at the tetrahedral voids of the anion structure, with saddle points between them.A number of novel experimental approaches toward a better understanding of the ion dynamics in α-AgI were suggested by Wilhelm Jost in the 1960s and 1970s. These included high-accuracy specific heat measurements, measurements of the ionic conductivity in the microwave and far-infrared frequency regimes, and quasielastic neutron scattering. The results of the ensuing experiments, involving the present author, did not always provide immediate answers to the long-standing open questions, but rather created new puzzles instead. In this Chapter, an overview is given of the essential steps that were taken in experiment and modeling, eventually leading to the emergence of a self-consistent picture of the structure and dynamics of the mobile silver ions in α-AgI. Notably, that picture included both solid-like and liquid-like aspects. Strictly speaking, however, either category, ‘solid’ and ‘liquid’, had to be considered inappropriate for characterizing the actual state of the silver-ion sublattice.Recently, the transition to a more solid-like behavior of the mobile silver ions was observed in low-temperature α-AgI, which could be stabilized by confinement in glass, as first shown by Tatsumisago et al. Far below the regular phase transition temperature, 147 °C, measurements were performed of the frequency-dependent conductivity of α-AgI, yielding relevant information on the silver-ion dynamics. A conjecture put forward by Jost in 1937 could thus be corroborated by the present author and his coworkers. Below 147 °C, the ‘liquid-like’ activation energy for ionic transport was found to be replaced by a larger, more ‘solid-like’ value, although the anion structure and, therefore, the barriers for elementary displacements of the cations remained essentially unchanged. The underlying mechanism is sketched at the end of the Chapter.

Dark Matter Halos as Particle Colliders: Unified Solution to Small-Scale Structure Puzzles from Dwarfs to Clusters.

Astrophysical observations spanning dwarf galaxies to galaxy clusters indicate that dark matter (DM) halos are less dense in their central regions compared to expectations from collisionless DM N-body simulations. Using detailed fits to DM halos of galaxies and clusters, we show that self-interacting DM (SIDM) may provide a consistent solution to the DM deficit problem across all scales, even though individual systems exhibit a wide diversity in halo properties. Since the characteristic velocity of DM particles varies across these systems, we are able to measure the self-interaction cross section as a function of kinetic energy and thereby deduce the SIDM particle physics model parameters. Our results prefer a mildly velocity-dependent cross section, from σ/m≈2 cm^{2}/g on galaxy scales to σ/m≈0.1 cm^{2}/g on cluster scales, consistent with the upper limits from merging clusters. Our results dramatically improve the constraints on SIDM models and may allow the masses of both DM and dark mediator particles to be measured even if the dark sector is completely hidden from the standard model, which we illustrate for the dark photon model.

Disappointment Aversion, Term Structure, and Predictability Puzzles in Bond Markets

Disappointment Aversion, Term Structure, and Predictability Puzzles in Bond Markets

ℤ2 SIMP dark matter

Dark matter with strong self-interactions provides a compelling solution to several small-scale structure puzzles. Under the assumption that the coupling between dark matter and the Standard Model particles is suppressed, such strongly interacting massive particles (SIMPs) allow for a successful thermal freeze-out through N-to-N′ processes, where N dark matter particles annihilate to N′ of them. In the most common scenarios, where dark matter stability is guaranteed by a ℤ2 symmetry, the seemingly leading annihilating channel, i.e. 3-to-2 process, is forbidden, so the 4-to-2 one dominate the production of the dark matter relic density. Moreover, cosmological observations require that the dark matter sector is colder than the thermal bath of Standard Model particles, a condition that can be dynamically generated via a small portal between dark matter and Standard Model particles, à la freeze-in. This scenario is exemplified in the context of the Singlet Scalar dark matter model.

Bond Market Demand and Capital Structure Variation

This paper investigates whether firms vary the debt side of their capital structure, based on changes in investor demand for bonds. Examining asset flows into various asset classes over the last 30 years reveals that companies respond to recent increases in demand for bonds from investors by altering their capital structure towards greater use of debt. Firms are more likely to issue debt as demand for bonds rises, and their use of debt increases (decreases) in periods when demand for bonds is high (low) compared to periods when demand is not significantly changed. Firms use more (less) debt when spreads between corporate yields and Treasury rates are low (high), consistent with efforts by managers to adjust their debt issuances based on relative debt costs. These results hold after controlling for seasonality, firm effects, and macroeconomic conditions. These findings suggest that investor demand for debt needs to be taken into account when examining the capital structure puzzle.

Untangling the Capital-Structure Puzzle: Solving for the Optimal Debt/Equity Ratio

This paper clarifies the capital structure puzzle. The traditional theories have forgotten to monitor the money raised from equity issuing. When included, the contribution of this source of finance becomes apparent. Though its productivity is the same as any money, including debt, its cost is much lower. The optimal debt/equity ratio is thus found to be the reciprocal of their prices.

Strongly interacting dark matter: Self-interactions and keV lines

We consider a simple supersymmetric hidden sector: pure SU(N) gauge theory. Dark matter is made up of hidden glueballinos with mass $m_X$ and hidden glueballs with mass near the confinement scale $\Lambda$. For $m_X \sim 1\,\text{TeV}$ and $\Lambda \sim 100\,\text{MeV}$, the glueballinos freeze out with the correct relic density and self-interact through glueball exchange to resolve small-scale structure puzzles. An immediate consequence is that the glueballino spectrum has a hyperfine splitting of order $\Lambda^2 / m_X \sim 10\,\text{keV}$. We show that the radiative decays of the excited state can explain the observed 3.5 keV X-ray line signal from clusters of galaxies, Andromeda, and the Milky Way.

Solving the RNA polymerase I structural puzzle.

Knowing the structure of multi-subunit complexes is critical to understand basic cellular functions. However, when crystals of these complexes can be obtained they rarely diffract beyond 3 Å resolution, which complicates X-ray structure determination and refinement. The crystal structure of RNA polymerase I, an essential cellular machine that synthesizes the precursor of ribosomal RNA in the nucleolus of eukaryotic cells, has recently been solved. Here, the crucial steps that were undertaken to build the atomic model of this multi-subunit enzyme are reported, emphasizing how simple crystallographic experiments can be used to extract relevant biological information. In particular, this report discusses the combination of poor molecular replacement and experimental phases, the application of multi-crystal averaging and the use of anomalous scatterers as sequence markers to guide tracing and to locate the active site. The methods outlined here will likely serve as a reference for future structural determination of large complexes at low resolution.

The Effects of Reversible Investment on Capital Structure and Credit Risks

We propose a structural model with an optimal switching of diffusion regime which integrates a wide range of investment reversibility. The default boundary and switching thresholds are endogenously determined, and we can examine conflict of interest between shareholders and creditors from various angles. In particular, the comparative statics show that the leverage ratio decreases when the firm has options to invest and to disinvest, which lead to the alleviation of the capital structure puzzle. Furthermore, the model may resolve the puzzle of dispersion of yield spreads depending on credit grade of bonds: namely, the yield spreads of junk bonds decrease up to 10% unless the agency problem gets extremely severe, and those of investment grade bonds increase 10∼15%

The Study of Relationship between Capital Structure , Firm Growth with Financial Leverage of the Company Listed in Tehran Stock Exchange

One of the most important issues that financial managers must consider in order to maximize shareholders wealth is to determine the best combination of company resources or the capital structure. The capital structure puzzle is one of the most important issues in the financial management and it is even more complicated than the dividend puzzle. The discussion of capital structure refers to the method of combination of companies financing sources, including debts, preferred stock and common stock. In this research, the relationship between the ownership structure, corporate growth with corporate financial leverage is addressed in companies being accepted in Tehran Stock Exchange using deducted simultaneous equation systems and panel data relating to 2007 – 2011. Generally, research findings indicate a relationship between the ownership structure, corporate growth and companies ‘administrative financial leverage.

Coded Polemic in Ammianus Book 31 and the Date and Place of its Composition

AbstractTheRes Gestaeof Ammianus Marcellinus poses numerous structural puzzles for the historian, among them the anomalous final book, numbered 31 in the manuscript tradition. This book, which treats the Gothic rebellion ofa.d.376–378 and the campaign of Adrianople, is loosely connected to the other extant books, which conclude with events ofa.d. 375. The present article argues that Book 31 was in origin a separate monograph, drafted in Greek at Antioch in the aftermath of the Roman defeat at Adrianople. Perhaps modelled on theScythicaof Dexippus, its contents reflect the Antiochene and Constantinopolitan polemic of its moment. For reasons that must remain speculative, Ammianus later translated his work into Latin and appended it to a finished draft of theRes Gestae.

E-Learning Turkish Language and Grammar: Analyzing Learners' Behavior.

This study analyses the behavior and the preferences of the Greek learners of Turkish language, who use a particular e-learning website in parallel with their studies, namely: http://turkish.pgeorgalas.gr. The website offers free online material in Greek and English language for learning the Turkish language and grammar. The traffic of several modules of the website has been measured, examined and analyzed. The research was carried out between the years 2010- 2011 and included the analysis of several million clicks. The results show particular attitudes, habits and preferences throughout the elearning process. There is a preference of users to exercises against theory. Fast crosslink exercises are preferred to slower “fill in” ones. During the weekends, visitors tend to use less e-learning facilities and select more light activities than the rest days of the week. Society trends and fashions like TV serials have a serious impact to the number of people who decide to learn a new foreign language, in particular Turkish. There is a strong preference of the audience to use online TV against online radio facilities for language practice. The subjects that Greek learners of Turkish language spend more time are verbs conjugation and vocabulary learning. They focus on elementary grammar subjects like the Alphabet, the numbers and the formation of plural. Finally, they try to learn the syntax of Turkish language through sentence structure puzzles and give priority to special grammar issues like noun compounds that are not present in Greek language.

Self-Assembly of Pyridine-Substituted Alkanethiols on Gold: The Electronic Structure Puzzle in the Ortho- and Para-Attachment of Pyridine to the Molecular Chain

X-ray photoelectron spectroscopy, near-edge X-ray absorption fine structure (NEXAFS) spectroscopy, infrared reflection absorption spectroscopy, and electrochemistry were applied to monitor the form...

Quaternary and Holocene coastal uplift in Ikaria Island, Aegean Sea

Geomorphological, biological and AMS radiocarbon dating provide evidence of an about lm high elevated palaeo-shoreline at the NE coast of Ikaria Island,Aegean Sea, and to a seismic uplift which occurred after AD950-1150 and was probably responsible for damage in an ancient tower. These data are important for several reasons. They provide evidence for a strong earthquake in an island usually assumed aseismic, coastal uplifts and coastal fauna are scarce in this region, while the Late Holocene uplift correlates with a flight of marine terraces of probably Quaternary age, at least up to 40m high. Long-term uplift is not observed at the footwall of a fault bounding a major graben north of Ikaria, it represents a structural puzzle and it may help to shed some light to the evolution of various extensional terranes.

Revisiting the capital‐structure puzzle: UK evidence

Purpose – This paper seeks to explore the potential drivers of corporate capital structure. Design/methodology/approach – The paper applies both fixed effects panel models and random effects tobit models to examine this issue. A sample of 379 firms is used across the period from 1991 to 2002. Findings – It is found that corporate characteristics (firm size, firm risk, firm growth rate, firm profitability and asset tangibility) and corporate governance characteristics (board size and outside directorships) are the main drivers of capital structure of UK firms. In addition, the results show that changing the definition of capital structure may result in changing the sign and the significance of these potential drivers. Originality/value – The paper argues that another dimension of the capital structure puzzle can be introduced which is related to the definition of capital structure used in prior studies. It is worth noting that the aim of this paper is not to provide an optimal set of factors that may affect the decision of capital structure, but to highlight the effect of the different definitions of capital structure that can be used by different studies, which makes the comparison between such studies difficult or even erroneous.

The determinants of capital structure choice: evidence from Greek listed companies

This article investigates the capital structure determination of firms listed on the Athens Stock Exchange, using both cross-sectional and nonparametric statistics. The data set is mainly composed of balance sheet data for 259 firms over a 9-year period from 1998 to 2006, excluding firms from the banking, finance, real estate and insurance sectors. The first part of the study assesses the extent to which leverage depends upon a broader set of capital structure determinants, while the latter provides evidence that capital structure varies significantly across a series of firm classifications. The results document empirical regularities with respect to alternative measures of debt that are consistent with existing theories and, in particular, reasonably support the pecking order hypothesis. Overall, this study tries to shed more light on corporate financing behaviour in a way to loosen the capital structure puzzle.

The Puzzles of Material Constitution

Monists about material constitution typically argue that when Statue is materially constituted by Clay, Statue is just Clay. Pluralists about material constitution deny that constitution is identity: Statue is not just Clay. When Clay materially constitutes Statue, Clay is not identical to Statue. I discuss three familiar puzzles involving grounding, overdetermination and conceptual issues, and develop three new puzzles stemming from the connection between mereological composition and material constitution: a mereological puzzle, an asymmetry puzzle, and a structural puzzle.

Dual coding in alternative reading frames correlates with intrinsic protein disorder

Numerous human genes display dual coding within alternatively spliced regions, which give rise to distinct protein products that include segments translated in more than one reading frame. To resolve the ensuing protein structural puzzle, we identified 67 human genes with alternative splice variants comprising a dual-coding region at least 75 nucleotides in length and analyzed the structural status of the protein segments they encode. The inspection of their amino acid composition and predictions by the IUPred and PONDR VSL2 algorithms suggest a high propensity for structural disorder in dual-coding regions. In the case of +1 frameshifts, the average level of disorder in the two frames is similarly high (47.2% in the ancestral frame, 58.2% in the derived frame, with the average level of disorder in human proteins being approximately 30%), whereas in the case of -1 frameshifts, there is a significant tendency to become more disordered upon shifting the frame (16.7% in the ancestral frame, 56.3% in the derived frame). The regions encoded by the derived frame are mostly disordered (disorder percentage > 50%) in 39 out of 62 cases, which strongly suggests that structural disorder enables these protein products to exist and function without the need of a highly evolved 3D fold. The potential advantages are also demonstrated by the appearance of novel functions and the high incidence of transcripts escaping nonsense-mediated decay. By discussing several examples, we demonstrate that dual coding may be an effective mechanism for the evolutionary appearance of novel intrinsically disordered regions with new functions.