Motives, Default Risk and Valuation Errors in Corporate Takeovers

Motivated by the plethora of theories in explaining the conflicting evidence on the acquiring firms’ profitability after a merger, this thesis examines how market conditions affect the most prominent takeover motives and the acquirers’ abnormal returns and analyse changes in acquiring firms’ default risk around the announcement on four different types of diversification. In the takeover process, information asymmetry holds a very central role, along with other firm and deal variables which release new information in the market and alter investors’ views. Further, market conditions around the announcements significantly affect not only the takeover activity but also investors’ beliefs and optimism which will eventually drive the acquirers’ stock prices. We first investigate the main takeover motives by analysing the wealth creation of the acquiring, the target firm and their combined gains. Firms react to both internal and external conditions by restructuring their business and takeovers are the fastest strategy to do so. Consequently, we re-examine takeover motives by incorporating the potential influence of market conditions (i.e. market misvaluation and merger waves). The results indicate that value increasing acquisitions are driven by both synergy and hubris, while value decreasing acquisitions by managerialism, after controlling for the hostility of the deal and extreme market valuations. We then turn our attention to the diversification benefits of mergers; although recent evidence suggests that mergers increase default risk for the acquiring firms, we find that due to the less uncertainty around horizontal mergers, acquirers can actually enjoy the risk-reducing diversification benefits of this related type of merger. Finally, we investigate how firm, market and industry valuation errors affect acquires performance in the UK market, after we control for multiple deals, method of payment and target type. Results suggest that although firm and deal characteristics help investors to revalue the potentials of an acquisition, investors are more likely to base their views on the state of the market/industry or the value of the firm and this will in turn drive the acquiring firms’ abnormal returns

An empirical evaluation of executive function in Autism Spectrum Disorder

Autism Spectrum Disorder (ASD) is a neurodevelopmental condition characterised by social impairment and restricted/repetitive behaviours. It is associated with significant disability and poor life outcomes with increasing interest in the factors that contribute to this disability. A significant body of research has focused on investigating the role of executive function (EF) in ASD. This thesis presents a series of studies that aim to advance the knowledge of EF in ASD. The studies considered factors that may moderate EF and investigated the role of EF in diagnosis and predicting disability. The research cohort comprised of youth and adults with ASD. Comparisons were made with clinical groups diagnosed with Social Anxiety Disorder and Early Psychosis. The first empirical study presented a meta-analysis of the extant literature on EF in ASD across the lifespan. Empirical studies 2 and 3, explored the role of moderators on EF including sex differences and affective states. Empirical study 4, examined the role of EF in differential diagnosis and in predicting disability. The final study utilised a machine learning paradigm and examined whether EF discriminated the ASD cohort from the comparison groups. The research results point to broad executive dysfunction in ASD not influenced by moderator variables or sex differences. Affective states moderated EF across all comparison groups, suggesting a transdiagnostic influence. EF differentiated the ASD cohort from comparison groups and was a unique predictor of disability for the ASD group only. The studies presented in this thesis highlight the importance of a multifaceted evaluation of EF in ASD. This will allow evaluation of unique and shared factors influencing disability outcomes, acknowledge the contribution of mental health factors to EF and facilitate targeted intervention and remediation programmes. Importantly, the cross diagnostic relevance of these factors could facilitate resource allocation and social inclusion

The role of APT imaging in gliomas grading: A systematic review and meta-analysis

Purpose: Gliomas are diagnosed and staged by conventional MRI. Although non-conventional sequences such as perfusion-weighted MRI may differentiate low-grade from high-grade gliomas, they are not reliable enough yet. The latter is of paramount importance for patient management. In this regard, we aim to evaluate the role of Amide Proton Transfer (APT) imaging in grading gliomas as a non-invasive tool to provide reliable differentiation across tumour grades. Methods: A systematic search of PubMed, Medline and Embase was conducted to identify relevant publications between 01/01/2008 and 15/09/2020. Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) was used to assess studies’ quality. A random-effects model standardized mean difference meta-analysis was performed to assess APT's ability to differentiate low-grade gliomas (LGGs) from high-grade gliomas (HGGs), WHO 2–4 grades, wild-type from mutated isocitrate dehydrogenase (IDH) gliomas, methylated from unmethylated O6-methylguanine-DNA methyltransferase (MGMT) gliomas. Area under the curve (AUC) of the Receiver Operating Characteristic (ROC) meta-analysis was employed to assess the diagnostic performance of APT. Results: 23 manuscripts met the inclusion criteria and reported the use of APT to differentiate glioma grades with histopathology as reference standard. APT-weighted signal intensity can differentiate LGGs from HGGs with an estimated size effect of (-1.61 standard deviations (SDs), p < 0.0001), grade 2 from grade 3 (-1.83 SDs, p = 0.005), grade 2 from grade 4 (-2.34 SDs, p < 0.0001) and IDH wild-type from IDH mutated (0.94 SDs, p = 0.003) gliomas. The combined AUC of 0.84 highlights the good diagnostic performance of APT-weighted imaging in differentiating LGGs from HGGs. Conclusions: APT imaging is an exciting prospect in differentiating LGGs from HGGs and with potential to predict the histopathological grade. However, more studies are required to optimize and improve its reliability

The mediterranean dietary pattern and breast cancer risk in Greek-Cypriot women: a case-control study

Background: Diet has long been suspected to impact on breast cancer risk. In this study we evaluated whether the degree of adherence to a Mediterranean diet pattern modifies breast cancer risk amongst Greek-Cypriot women. Methods: Subjects included 935 cases and 817 controls, all participating in the MASTOS case-control study in Cyprus. The study was approved by the Cyprus National Bioethics Committee. Information on dietary intakes was collected using an interviewer administered 32-item Food Frequency Questionnaire. Information on demographic, anthropometric, lifestyle, and other confounding factors was also collected. Adherence to the Mediterranean Diet pattern was assessed using two a-priory defined diet scores. In addition, dietary patterns specific to our population were derived using Principal Component Analysis (PCA). Logistic regression models were used to assess the association between the dietary patters and breast cancer risk. Results: There was no association with breast cancer risk for either score, however, higher consumptions of vegetables, fish and olive oil, were independently associated with decreased risk. In addition, the PCA derived component which included vegetables, fruit, fish and legumes was shown to significantly reduce risk of breast cancer (ORs across quartiles of increasing levels of consumption: 0.89 95%CI: 0.65-1.22, 0.64 95%CI: 0.47-0.88, 0.67 95%CI: 0.49-0.92, P trend < 0.0001), even after adjustment for relevant confounders. Conclusions: Our results suggest that adherence to a diet pattern rich in vegetables, fish, legumes and olive oil may favorably influence the risk of breast cancer. This study is the first investigation of dietary effects on breast cancer risk in Cyprus, a country whose population has traditionally adhered to the Mediterranean diet

Mitochondrial superclusters influence age of onset of Parkinson’s disease in a gender specific manner in the Cypriot population: A case-control study

Despite evidence supporting an involvement of mitochondrial dysfunction in the pathogenesis of some neurodegenerative disorders, there are inconsistent findings concerning mitochondrial haplogroups and their association to neurodegenerative disorders, including idiopathic Parkinson's disease (PD).To test this hypothesis for the Greek-Cypriot population, a cohort of 230 PD patients and 457 healthy matched controls were recruited. Mitochondrial haplogroup distributions for cases and controls were determined. Association tests were carried out between mitochondrial haplogroups and PD.Mitochondrial haplogroup U was associated with a reduced PD risk in the Cypriot population. After pooling mitochondrial haplogroups together into haplogroup clusters and superclusters, association tests demonstrated a significantly protective effect of mitochondrial haplogroup cluster N (xR) and supercluster LMN for PD risk only in females. In addition, for female PD cases belonging to UKJT and R (xH, xUKJT) haplogroup, the odds of having a later age of onset of PD were 13 and 15 times respectively higher than the odds for female cases with an H haplogroup.Statistically significant associations regarding PD risk and PD age of onset were mostly detected for females thus suggesting that gender is a risk modifier between mitochondrial haplogroups and PD status / PD age of onset. The biological mechanisms behind this gender specificity remain to be determined

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Effects of exchange rate on chemical exchange saturation transfer

The general work presented in this thesis describes the implementation and optimization of CEST MRI techniques on a preclinical 9.4 T MRI scanner for quantifying the chemical exchange rate or the exchange relaxation term both in vitro and in pathological conditions. A novel pulse sequence for measuring chemical exchange rates through a progressive saturation recovery process, called PRO-QUEST (PROgressive saturation for Quantifying Exchange rates using Saturation Times) has been developed. A complete theoretical framework has been set up, and the exchange rates calculated in several aminoacids using PRO-QUEST were compared and found in good agreement with standard methods. A reduction of scan time from 58min to 16min has been obtained using PRO-QUEST for measurement in both healthy and infarcted rat after 24 hours and revealed that imaging specificity to ischemic acidification was substantially increased relative to standard APT-weighted imaging. The second part of this thesis describes the development of CEST contrast agents based on liposome encapsulation. For this work a concise analytical model has been developed for characterizing the liposomal contrast. In addition, combining this analytical model with measurements of the CEST signal enhancement using liposomes as a model membrane system provides a new technique for studying membrane permeability. All theoretical developments are included as part of this second major chapter. The final part of the thesis describes applications of CEST and high-resolution magnetic resonance spectroscopy for studying prion protein misfolding and neurodegeneration in Prion disease. Here alterations in CEST signal are detected before structural changes or any clinical signs of Prion disease, most likely based on changes in exchange rates, which is encouraging for translation of CEST imaging for early detection of neurodegenerative processes. Thus, CEST signal displays different patterns at different stages of the disease indicating the potential of using CEST to separate different groups of Prion-infected mice

Passer de l'art au patrimoine. Une énigme socio-historique

International audienc

A category and its absence from heritage policy making: the case of ‘funerary heritage’

International audienc