The Declining Information Content of Dividend Announcements and the Effects of Institutional Holdings

We propose an explanation for the “disappearing dividend” phenomenon: a decline in the information content of dividend announcements, which reduces the propensity of firms to use dividends as a costly signal. A reason for a decline in the information content of dividends is the rise in holdings by institutional investors that are more sophisticated and informed. We indeed find a decline in CAR at dividend change announcements since the mid 1970s. Across firms, CAR is a decreasing function of institutional holdings. Institutional investors exploit their superior information and buy before dividend increases. And, dividends are less likely to rise in firms with high institutional holdings

The Declining Information Content of Dividend Announcements and the Effect of Institutional Holdings

We propose an explanation for the "disappearing dividend" phenomenon: the decline in the information content of dividend announcements. This reduces the propensity of firms to pay or increase dividends, since dividends are costly. The decline in the information content of dividend, is partly because of the rise in stockholding by institutional investors that are more sophisticated and informed. Our results show a decline in the stock price reaction to announcements of dividend changes since the mid 1970s. Across firms, the price reaction to dividend news is smaller in firms with high institutional holdings. Institutional investors exploit their superior information by buying before dividend increases and selling afterwards. And, firms with high institutional holdings are less likely to raise dividends

Altered kinetics of nonhomologous end joining and class switch recombination in ligase IV–deficient B cells

Immunoglobulin heavy chain class switch recombination (CSR) is believed to occur through the generation and repair of DNA double-strand breaks (DSBs) in the long and repetitive switch regions. Although implied, the role of the major vertebrate DSB repair pathway, nonhomologous end joining (NHEJ), in CSR has been controversial. By somatic gene targeting of DNA ligase IV (Lig4; a key component of NHEJ) in a B cell line (CH12F3) capable of highly efficient CSR in vitro, we found that NHEJ is required for efficient CSR. Disruption of the Lig4 gene in CH12F3 cells severely inhibits the initial rate of CSR and causes a late cell proliferation defect under cytokine stimulation. However, unlike V(D)J recombination, which absolutely requires NHEJ, CSR accumulates to a substantial level in Lig4-null cells. The data revealed a fast-acting NHEJ and a slow-acting alterative end joining of switch region breaks during CSR

Study on the analytical model of vibration source for metro train

A novel analytical model of vibration source for metro train based on “coupled vehicle and track basic unit” is established in this paper. The dynamic vehicle-track equations are completed with the displacement compatibility and the force equilibrium, and the model takes into account the infinite track structure, whole vehicle, track irregularity and wheel-rail Hertz contact. The special feature of track structure model is the periodical system of discrete supported sleepers, which converts the infinite integral equation into the combination in the wave number-frequency domain and simplifies the calculation progress. The rail dynamic responses and the wheel-rail contact force can be calculated easily. A complete software package TMCVT is programmed. A calculated example is achieved using the program. Compared the theoretical calculated results and the field tested results ,the coincidence with each other proved the analytical dynamic model for metro train coupled with vehicle and track is correct

Numerical modelling of non-uniform corrosion induced concrete crack width

Corrosion of reinforced concrete is one of the major deterioration mechanisms which result in premature failure of the reinforced concrete structures. Crack width is often used as an effective criterion to assess the serviceability of concrete structures. However, research on prediction of corrosion-induced concrete crack width, especially by considering the corrosion as a non-uniform process, has still been scarce. This paper attempts to develop a finite element model to predict the crack width for corrosion-affected concrete structures under realistic non-uniform corrosion of the reinforcement. A non-uniform corrosion model was first formulated as a function of time. To simulate arbitrary cracking in concrete, cohesive elements are inserted in the sufficiently fine mesh which is achieved through a script written in Python. The surface crack width is obtained as a function of service time and verification against experimental results from literature is conducted. Accurate prediction of crack width can allow timely maintenance which prolongs the service life of the reinforced concrete structures

Analytical solution for dynamic response of curved rail subjected to moving train

The objective of this paper is to present an analytical solution for the dynamic response of curved rail. The detailed solution was derived for the out-of-plane vibration response of periodically supported curved Timoshenko beam subjected to moving loads. The accuracy of the solution was validated based on the results from previous study. Furthermore, the train/track interaction model was introduced into this solution to calculate the rail dynamic response in Beijing metro. The results presented herein indicated that the solution provided accurate results in comparison with both the result from previous study and the measurement data collected from Beijing metro and it can be used to derive the dynamic response for similar situations

Hysteretic and Scanning Behaviors of Water Vapor Sorption in Hardened Cement Pastes

Water in the multiscale porous microstructure of cement-based materials is closely related to multiple deterioration processes, hence significantly influences the durability of concrete structures in atmospheric environment. Water vapor sorption is the key tool for characterizing the hygroscopic properties of cement-based materials, also a promising technique for exploring their nanopore structures. The significant hysteresis between different sorption branches is stemmed from the complexity of interconnecting pore system and concurrence of different physical phenomena. In this study, the hysteretic and scanning behaviors of water vapor sorption in hardened cement pastes are measured with a dynamic vapor sorption instrument, and investigated to provide new insights into the path-dependency of sorption behaviors on humidity history and resolve the overall sorption hysteresis into contributions from different phenomena

DNA Ligase I Is Not Essential for Mammalian Cell Viability

SummaryOf the three DNA ligases present in all vertebrates, DNA ligase I (Lig1) has been considered essential for ligating Okazaki fragments during DNA replication and thereby essential for cell viability. Here, we report the striking finding that a Lig1-null murine B cell line is viable. Surprisingly, the Lig1-null cells exhibit normal proliferation and normal immunoglobulin heavy chain class switch recombination and are not hypersensitive to a wide variety of DNA damaging agents. These findings demonstrate that Lig1 is not absolutely required for cellular DNA replication and repair and that either Lig3 or Lig4 can substitute for the role of Lig1 in joining Okazaki fragments. The establishment of a Lig1-null cell line will greatly facilitate the characterization of DNA ligase function in mammalian cells, but the finding alone profoundly reprioritizes the role of ligase I in DNA replication, repair, and recombination

Identifying progressive imaging genetic patterns via multi-task sparse canonical correlation analysis: a longitudinal study of the ADNI cohort

Motivation Identifying the genetic basis of the brain structure, function and disorder by using the imaging quantitative traits (QTs) as endophenotypes is an important task in brain science. Brain QTs often change over time while the disorder progresses and thus understanding how the genetic factors play roles on the progressive brain QT changes is of great importance and meaning. Most existing imaging genetics methods only analyze the baseline neuroimaging data, and thus those longitudinal imaging data across multiple time points containing important disease progression information are omitted. Results We propose a novel temporal imaging genetic model which performs the multi-task sparse canonical correlation analysis (T-MTSCCA). Our model uses longitudinal neuroimaging data to uncover that how single nucleotide polymorphisms (SNPs) play roles on affecting brain QTs over the time. Incorporating the relationship of the longitudinal imaging data and that within SNPs, T-MTSCCA could identify a trajectory of progressive imaging genetic patterns over the time. We propose an efficient algorithm to solve the problem and show its convergence. We evaluate T-MTSCCA on 408 subjects from the Alzheimer’s Disease Neuroimaging Initiative database with longitudinal magnetic resonance imaging data and genetic data available. The experimental results show that T-MTSCCA performs either better than or equally to the state-of-the-art methods. In particular, T-MTSCCA could identify higher canonical correlation coefficients and capture clearer canonical weight patterns. This suggests that T-MTSCCA identifies time-consistent and time-dependent SNPs and imaging QTs, which further help understand the genetic basis of the brain QT changes over the time during the disease progression. Availability and implementation The software and simulation data are publicly available at https://github.com/dulei323/TMTSCCA. Supplementary information Supplementary data are available at Bioinformatics online

THE DECLINING INFORMATION CONTENT OF DIVIDEND ANNOUNCEMENTS AND THE EFFECT OF INSTITUTIONAL HOLDINGS

We propose an explanation for the “disappearing dividend” phenomenon: the decline in the information content of dividend announcements. It reduces the propensity of firms to pay or increase dividends, since dividends are costly. A reason for the decline in the information content of dividends is the rise in holdings by institutional investors that are more sophisticated and informed. We indeed find a decline in CAR at dividend change announcements since the mid 1970s. Across firms, CAR declines in institutional holdings. Exploiting their superior information, institutional investors buy before dividend increases and sell afterwards. And, dividends are less likely to rise in firms with high institutional holdings