Event study methodology in analysing real estate investment trust returns

This study investigates the influence of cash rate changes on the equity A-REIT stock prices in the past decade. The findings indicate that cash rate changes can influence the fluctuation of the equity A-REIT stock prices. Moreover, cash rate changes affect small A-REITs to a greater extent than large A-REITs.</p

Long-term abnormal stock performance: UK evidence

One of the most controversial issues for long-term stock performance is whether the presence of anomalies is against the efficient market hypothesis. The methodologies to measure abnormal returns applied in the long-run event studies are questioned for their reliability and specification. This thesis compares three major methodologies via a simulation process based on the UK stock market over a period of 1982 to 2008 with investment horizons of one, three and five years. Specifically, the methodologies that are compared are the event-time methods based on models (Chapter 3), the event-time methods based on reference portfolios (Chapter 4), and the calendar-time methods (Chapter 5). Chapter 3 covers the event-time approach based on the following models which are used to estimate normal stock returns: the market-adjusted model, the market model, the capital asset pricing model, the Fama-French three-factor model and the Carhart four-factor model. The measurement of CARs yields misspecification with higher rejection rates of the null hypothesis of zero abnormal returns. Although the application of standard errors estimated from the test period improves the misspecification, CARs still yield misspecified test statistics. When using BHARs, well-specified results are achieved when applying the market-adjusted model, capital asset pricing model and Fama-French three-factor model over all investment horizons. It is important to note that the market model is severely misspecified with the highest rejection rates under both measurements. The empirical results from simulations of event-time methods based on reference portfolios in Chapter 4 indicate that the application of BHARs in conjunction with p-value from pseudoportfolios is appropriate for application in the context of long-run event studies. Furthermore, the control firm approach together with student t-test statistics is proved to yield well-specified test statistics in both random and non-random samples. Firms in reference portfolios and control firms are selected on the basis of size, BTM or both. However, in terms of power of test, these two approaches have the least power whereas the skewness-adjusted test and bootstrapped skewness-adjusted test have the highest power. It is worth noting that when the non-random samples are examined, the benchmark portfolio or control firm needs to share at least one characteristic with the event firm. The calendar-time approach is suggested in the literature to overcome potential issues with event-time approaches like overlapping returns and calendar month clustering. Chapter 5 suggests that both three-factor and four-factor models present significant overrejections of the null hypothesis of zero abnormal returns under an equally-weighted scheme. Even for stocks under a value-weighted scheme, the rejection rate for small firms shows overrejection. This indicates the small size effect is more prevalent in the UK stock market than in the US and the calendar-time approach cannot resolve this issue. Compared with the three-factor model, the four-factor model, despite its higher explanatory power, improves the results under a value-weighted scheme. The ordinary least squares technique in the regression produces the smallest rejection rates compared with weighted least squares, sandwich variance estimators and generalized weighted least squares. The mean monthly calendar time returns, combining the reference portfolios and calendar time, show similar results to the event-time approach based on reference portfolios. The weighting scheme plays an insignificant role in this approach. The empirical results suggest the following methods are appropriately applied to detect the long-term abnormal stock performance. When the event-time approach is applied based on models, although the measurement of BHARs together with the market-adjusted model, capital asset pricing model and Fama-French three-factor model generate well-specified results, the test statistics are not reliable because BHARs show severe positively skewed and leptokurtic distribution. Moreover, the reference portfolios in conjunction with p-value from pseudoportfolios and the control firm approach with student t test in the event-time approach are advocated although with lower power of test. When it comes to the calendar-time approach, the three-factor model under OLS together with sandwich variance estimators using the value-weighted scheme and the mean monthly calendar-time abnormal returns under equal weights are proved to be the most appropriate methods

Exploring the Structure, Function & Regulation of the Human Glucagon-Like Peptide-1 Receptor

Glucagon-like peptide-1 (GLP-1) enhances glucose-dependent insulin secretion and promotes β-cell function via its receptor (GLP-1R), which therefore is a validated target for the treatment of type 2 diabetes. Due to difficulties with peptide therapeutics, it is important to find small-molecule GLP-1R agonists. This leads to a need to understand the structure, function and regulation of the receptor, particularly, differences between agonisms mediated by GLP-1 (orthosteric agonist) and small molecules. The GLP-1R contains a putative N-terminal signal peptide sequence, which is assessed here by recombinantly expressing several epitope-tagged GLP-1R constructs in HEK293 cells. The findings demonstrate that the GLP-1R is expressed predominately at the plasma membrane and also slightly cytosolic. Only fully glycosylated, mature form of the receptor is able to traffic to the cell surface and performs the function. The signal peptide sequence of the GLP-1R is essential for synthesis. After fulfilling the function, this sequence is cleaved and thus not part of the mature protein. The cleavage of signal peptide is critical for processing and trafficking of the GLP-1R. Based on one of these constructs generated here, a cell line (HEK293: GLP-1R-EGFP) with stable expression of the visible GLP-1R is established, which allows observations and determinations for ligand-mediated receptor internalisation in real time. Compound 2 (6,7-dichloro-2-methylsulfonyl-3-N-tert-butylaminoquinoxaline) has been described as a GLP-1R allosteric modulator and agonist. Findings here that compound 2-mediated agonisms on both the wild-type (WT) GLP-1R and the mutant with removal of the N-terminal domain provide direct evidence for the allosteric agonism. Interestingly, compound 2-mediated cAMP response is enhanced by orthosteric antagonist exendin 9-39, but the latter inhibits receptor internalisation mediated by compound 2. Recently, it has been hypothesised that the binding of GLP-1 allows a sequence of NRTFD (Asn63-Asp67) in the N-terminus of the GLP-1R to interact with another part of the receptor and cause agonism. This was examined here by generating receptor mutants and synthetic peptides. Findings here that Asp67 plays a key role in stabilising the N-terminal structure of the GLP-1R and thus is critical for processing and trafficking of the receptor protein do not support such hypothesis although synthetic NRTFD mediates a weak and partial agonism on the WTGLP-1R

Jet2 Features

This folder includes the features of human and yeast proteins calculated by Jet2.</p

Circ_0007841 knockdown confers cisplatin sensitivity to ovarian cancer cells by down-regulation of NFIB expression in a miR-532-5p-dependent manner

Cisplatin (DDP) is first-line management for ovarian cancer (OC). Previous data have suggested that circular RNA_0007841 (circ_0007841) regulates OC progression; however, there is no data on its role in the sensitivity of OC cells to DDP. RNA expression of circ_0007841, microRNA-532-5p (miR-532-5p) and nuclear factor I B (NFIB) was detected by quantitative real-time polymerase chain reaction in OC patient samples and OC cell lines. Protein expression was checked by Western blotting analysis. Cell viability, proliferation, cell apoptotic rate, migration and invasion were investigated by 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-diphenytetrazoliumromide, 5-Ethynyl-29-deoxyuridine, flow cytometry analysis, scratch test and transwell assays, respectively. The interactions among circ_0007841, miR-532-5p and NFIB were identified by a dual-luciferase reporter assay. Xenograft mouse model assay was performed to determine the effect of circ_0007841 on DDP sensitivity in vivo. Circ_0007841 and NFIB expression were upregulated, whereas miR-532-5p was downregulated in DDP-resistant OC tissues and cells compared with controls. Circ_0007841 silencing improved DDP sensitivity, inhibited cell proliferation, invasion and migration, but induced cell apoptosis in DDP-resistant OC cells. Circ_0007841 acted as a miR-532-5p sponge and regulated DDP resistance and OC cell malignancy through miR-532-5p in DDP-resistant OC cells. Besides, the overexpression of NFIB, a target of miR-532-5p, remitted miR-532-5p-mediated effects in DDP-resistant OC cells. Circ_0007841 depletion conferred DDP sensitivity to DDP-resistant OC cells in vivo. Further, circ_0007841 was secreted from DDP-resistant OC cells through being packaged into exosomes. Circ_0007841 conferred DDP resistance to DDP-resistant OC cells through the miR-532-5p/NFIB axis, suggesting the potential of circ_0007841 as a therapeutic target for OC.</p

An Equivalent Dynamic Gas Network Model with Electricity–Gas Systems

As the coupling relationship between a natural gas system and electricity system deepens, the gas generator set will cause the fluctuation of natural gas systems while meeting the variation in demand of the electricity system. In order to quantify the impact of gas demand uncertainty for gas the generator set on the natural gas systems, an equivalent dynamic natural gas network model is presented in this paper. By introducing the concept of electrical analogy, the natural gas transmission equation is established, so that the gas flow in each pipeline is coupled to be calculated simultaneously. The disturbance factor of a gas demand change in an electrical system is introduced into dynamic modeling of gas networks, and the equivalent dynamic natural gas network model is developed. The proposed model effectively expresses the explicit dynamic response relationship between the pressure at a node and the gas demand of gas-fired generators in the form of an analytical formula, which can sufficiently reflect the dynamic performance of a natural gas system under disturbance of the electricity system with the action of electricity–gas coupling, laying the foundation for dynamic analysis of the electricity–gas system. Case studies on a 5-node natural gas network and the integrated electricity–gas system consisting of a 10-node natural gas network and IEEE 14-bus system indicate that the equivalent dynamic model is capable of effectively describing the dynamic response relationship

Monovalent Salt Enhances Colloidal Stability during the Formation of Chitosan/Tripolyphosphate Microgels

Chitosan micro- and nanoparticles are routinely prepared through ionotropic gelation, where sodium tripolyphosphate (TPP) is added as a cross-linker to dilute chitosan solutions. Despite the wide use of these gel-like particles, their preparation currently relies on trial and error. To address this, we used isothermal titration calorimetry (ITC), dynamic light scattering (DLS), transmission electron microscopy (TEM), and ζ-potential measurements to investigate how the formation, structure, and colloidal stability of chitosan microgels are linked to the molecular interactions that underlie their self-assembly. The strength of the chitosan/TPP interactions was systematically varied through the addition of monovalent salt (NaCl). Remarkably, and contrary to other colloidal systems, this revealed that moderate amounts of NaCl (e.g., 150 mM) enhance the colloidal stability of chitosan/TPP microgels during their formation. This stems from the weakened chitosan/TPP binding, which apparently inhibits the bridging of the newly formed microgels by TPP. The enhanced colloidal stability during the ionic cross-linking process yields microgels with dramatically narrower size distributions, which hitherto have typically required the deacetylation and fractionation of the parent chitosan. Conversely, at high ionic strengths (ca. 500 mM) the chitosan/TPP binding is weakened to the point that the microgels cease to form, thus suggesting the existence of an optimal ionic strength for ionotropic microgel preparation

Salt-Assisted Mechanistic Analysis of Chitosan/Tripolyphosphate Micro- and Nanogel Formation

Self-assembled micro- and nanogels are frequently prepared by mixing tripolyphosphate (TPP) with dilute chitosan solutions. Upon its addition, the TPP ionically cross-links the chitosan molecules into gel-like colloids that range from tens of nanometers to micrometers in diameter. These particles are biocompatible, mucoadhesive and, because they are easy to prepare under very mild conditions, attract widespread interest in the encapsulation of drugs, neutraceuticals, and other bioactive payloads. Despite their broad use, however, their formation mechanism has remained largely obscured by the very fast kinetics of their self-assembly. To this end, we have tuned the TPP and monovalent salt (NaCl) concentrations to dramatically slow down this process (to occur on the time scale of days instead of milliseconds), and then probed the evolution in the size and morphology of micro- and nanogels during their formation. This revealed that the micro- and nanogel formation rates are extremely sensitive to NaCl and TPP concentrations, and that the formation process occurs in two stages: (1) formation of small primary nanoparticles and (2) aggregation of primary particles into larger, higher-order colloids that are obtained at the end of the ionotropic gelation process

Determining the Colloidal Behavior of Ionically Cross-Linked Polyelectrolytes with Isothermal Titration Calorimetry

Mixtures of polyelectrolytes and multivalent counterions can self-assemble into colloidal complexes. These complexes attract widespread interest in applications such as medicine, household product formulations, and separation processes. To facilitate the development of these colloidal dispersions, we examined isothermal titration calorimetry (ITC) as an automated screening tool for identifying the polymer and multivalent counterion compositions that (1) form ionically cross-linked colloidal complexes and (2) lead to their rapid coagulation (and macroscopic phase separation). By studying various polyelectrolyte/multivalent counterion mixtures, we have identified and generalized the features in the ITC data that indicate colloidal complex formation and coagulation. The limitations of this calorimetric screening method were also elucidated. These analyses suggest that ITC can be effective for screening the short-term colloidal behavior of polyelectrolyte/multivalent counterion mixtures but are unreliable in revealing their long-term (equilibrium) properties

Additional file 1 of Current practices of peripheral intravenous catheter fixation in pediatric patients and factors influencing pediatric nurses’ knowledge, attitude and practice concerning peripheral intravenous catheter fixation: a cross-sectional study

Additional file 1. Pediatric PIVC Fixation Standard Checklist (First insertion). Pediatric PIVC Fixation Standard Checklist (Routine maintenance). SOP for Peripheral Intravenous Catheter Fixation