It's the market power, stupid! Stock return patterns in international bank M&A

This paper analyzes capital market reactions to international bank M&A. We investigate combined stock return patterns of targets, bidders, and their peers upon takeover announcement, and closing or withdrawal. We distinguish five common M&A hypotheses and relate characteristic and mutually exclusive abnormal stock return patterns to each hypothesis. We find that investors believe in gains through the exploitation of market power by the post-merger entity. In a multinomial logistic model we show that patterns related to market power significantly concur with large relative target size, intra-industry mergers, and increasing market concentration, suggesting a substantial lessening of competition through M&A. --M&A,Banks,Event Study,Peer Returns,Market Power

On Minimal Pumping Constants for Regular Languages

The study of the operational complexity of minimal pumping constants started in [J. DASSOW and I. JECKER. Operational complexity and pumping lemmas. Acta Inform., 59:337-355, 2022], where an almost complete picture of the operational complexity of minimal pumping constants for two different variants of pumping lemmata from the literature was given. We continue this research by considering a pumping lemma for regular languages that allows pumping of sub-words at any position of the considered word, if the sub-word is long enough [S. J. SAVITCH. Abstract Machines and Grammars. 1982]. First we improve on the simultaneous regulation of minimal pumping constants induced by different pumping lemmata including Savitch's pumping lemma. In this way we are able to simultaneously regulate four different minimal pumping constants. This is a novel result in the field of descriptional complexity. Moreover, for Savitch's pumping lemma we are able to completely classify the range of the minimal pumping constant for the operations Kleene star, reversal, complement, prefix- and suffix-closure, union, set-subtraction, concatenation, intersection, and symmetric difference. In this way, we also solve some of the open problems from the paper that initiated the study of the operational complexity of minimal pumping constants mentioned above.Comment: In Proceedings AFL 2023, arXiv:2309.0112

Identifying vacancy complexes in compound semiconductors with positron annihilation spectroscopy: a case study of InN

We present a comprehensive study of vacancy and vacancy-impurity complexes in InN combining positron annihilation spectroscopy and ab-initio calculations. Positron densities and annihilation characteristics of common vacancy-type defects are calculated using density functional theory and the feasibility of their experimental detection and distinction with positron annihilation methods is discussed. The computational results are compared to positron lifetime and conventional as well as coincidence Doppler broadening measurements of several representative InN samples. The particular dominant vacancy-type positron traps are identified and their characteristic positron lifetimes, Doppler ratio curves and lineshape parameters determined. We find that In vacancies and their complexes with N vacancies or impurities act as efficient positron traps, inducing distinct changes in the annihilation parameters compared to the InN lattice. Neutral or positively charged N vacancies and pure N vacancy complexes on the other hand do not trap positrons. The predominantly introduced positron trap in irradiated InN is identified as the isolated In vacancy, while in as-grown InN layers In vacancies do not occur isolated but complexed with one or more N vacancies. The number of N vacancies per In vacancy in these complexes is found to increase from the near surface region towards the layer-substrate interface.Comment: 10 pages, 6 figure

Private Equity Portfolio Company Fees

In private equity, General Partners (GPs) may receive fee payments from companies whose board they control. This paper describes the related contracts and shows that these fee payments sum up to $20 billion evenly distributed over the last twenty years, representing over 6% of the equity invested by GPs on behalf of their investors. Fees do not vary according to business cycles, company characteristics, or GP performance. Fees vary significantly across GPs and are persistent within GPs. GPs charging the least raised more capital post financial crisis. GPs that went public distinctively increased their fees prior to that event. We discuss how results can be explained by optimal contracting versus tunneling theories

Anthropocentric perspective of production before and within Industry 4.0

Abstract This paper presents a systematic literature review (SLR) of the anthropocentric perspective of production before and after (or, better, within) Industry 4.0. We identify central research clusters regarding traditional Anthropocentric Production Systems (APS) and Anthropocentric Cyber Physical Production Systems. By comparing the two perspectives, we are able to analyse new emerging paradigms in anthropocentric production caused by Industry 4.0. We further make prediction of the future role of the human operator, his needed knowledge and capabilities and how assistance systems support the Operator 4.0. Our paper gives a brief outlook of current and needed future research. It builds grounds for further scholarly discussion on the role of humans in the factory of the future

Tracking defect-induced ferromagnetism in GaN:Gd

We report on the magnetic properties of GaN:Gd layers grown by molecular beam epitaxy (MBE). A poor reproducibility with respect to the magnetic properties is found in these samples. Our results show strong indications that defects with a concentration of the order of 10^19 cm^-3 might play an important role for the magnetic properties. Positron annihilation spectroscopy does not support the suggested connection between the ferromagnetism and the Ga vacancy in GaN:Gd. Oxygen co-doping of GaN:Gd promotes ferromagnetism at room temperature and points to a role of oxygen for mediating ferromagnetic interactions in Gd doped GaN

Fraud in startups: what stakeholders need to know

Purpose: This paper aims to explain the fundraising and valuation processes of startups and discuss the conflicts of interest between entrepreneurs, venture capital (VC) firms and stakeholders in the context of startup corporate governance. Further, this paper uses the examples of WeWork and Zenefits to explain how a failure of stakeholders to demand an external audit from an independent accounting firm in early stages of funding led to an opportunity for fraud. Design/methodology/approach: The methodology used is a literature review and analysis of startup valuation combined with the Fraud Triangle Theory. This paper also provides a discussion of WeWork and Zenefits, both highly visible examples of startup fraud, and explores an increased role for independent external auditors in fraud risk mitigation on behalf of stakeholders prior to an initial public offering (IPO). Findings: This paper documents a number of fraud risks posed by the “fake it till you make it” ethos and investor behavior and pricing in the world of entrepreneurial finance and VC, which could be mitigated by a greater awareness of startup stakeholders of the value of an external audit performed by an independent accounting firm prior to an IPO. Research limitations/implications: An implication of this paper is that regulators should consider greater oversight of the startup financing process and potentially take steps to facilitate greater independence of participants in the IPO process. Practical implications: Given the potential conflicts of interest between VC firms, investment banks and startup founders, the investors at the time of an IPO may be exposed to the risk that the shares of the IPO firms are overvalued at offering. Social implications: This study demonstrates how startup practices can be extended to the Fraud Triangle and issue a call to action for the accounting profession to take a greater role in protecting the public from startup fraud. This study then offers recommendations for regulators and standards entities. Originality/value: There are few academic papers in the financial crime literature that link the valuation and culture of startup firms with fraud risk. This study provides a concise explanation of the process of valuation for startups and highlights the considerations for stakeholders in assessing fraud risk. In addition, this study documents an emerging role for auditors as stewards of proper valuation for pre-IPO firms

Defect studies in n-type indium nitride

Sparked by the discovery of its narrow bandgap, indium nitride (InN) has recently attracted major scientific interest as a promising material in opto- and high-speed electronics. Industrial application, however, is hampered by the material's strong propensity for n-type conductivity and high defect concentrations. Despite major research efforts in that area, relatively little is known about the properties of defects in InN. The main goal of this thesis was to study the formation and characteristics of native point defects in n-type InN and investigate their role for the material's electrical properties. Positron annihilation spectroscopy was used as the main experimental technique for defect characterization. By combining density functional theory calculations with experimental positron annihilation methods, the dominant vacancy-type positron traps in common InN material were identified. As-grown and n-doped InN layers that were deposited by different growth methods, as well as irradiated and annealed material with varying carrier concentrations, were analyzed to investigate the formation and evolution of point defects in different environments. The data were compared to results from complementary techniques in order to study the interplay of point and extended defects, and their role in limiting the conductivity in n-type InN. It is found that isolated indium (In) vacancies and their complexes are the dominant vacancy-type positron traps in InN. Isolated In vacancies are introduced in high-energy particle irradiation of InN, and anneal out at moderate temperatures if not stabilized by one or more nitrogen (N) vacancies. In-N vacancy complexes are the dominant vacancy-type positron traps in as-grown InN. In state-of-the-art material with low free electron concentrations, their concentration is at or below the detection limit of positron annihilation methods. For increasing free electron concentration, an enhanced formation of these vacancy complexes is observed, which act as significant source of compensation and scattering centers in highly n-type material. Additionally, a high density of negatively charged defects with only small effective open-volume is found that is tentatively attributed to negatively charged N vacancies. Estimated defect densities are significantly higher than what is expected from thermodynamic considerations, which suggests that alternative defect formation mechanisms determine the point defect densities in the material

Visual articulated tracking in cluttered environments

This thesis is concerned with the state estimation of an articulated robotic manipulator during interaction with its environment. Traditionally, robot state estimation has relied on proprioceptive sensors as the single source of information about the internal state. In this thesis, we are motivated to shift the focus from proprioceptive to exteroceptive sensing, which is capable to represent a holistic interpretation of the entire manipulation scene. When visually observing grasping tasks, the tracked manipulator is subject to visual distractions caused by the background, the manipulated object and by occlusions from other objects present in the environment. The aim of this thesis is to investigate and develop methods for the robust visual state estimation of articulated kinematic chains in cluttered environments which suffer from partial occlusions. To make these methods widely applicable to a variety of kinematic setups and unseen environments, we intentionally refrain from using prior information about the internal state of the articulated kinematic chain, and we do not explicitly model visual distractions such as the background and manipulated objects in the environment. We approach this problem with model-fitting methods, in which an articulated model is associated to the observed data using discriminative information. We explore model-fitting objectives that are robust to occlusions and unseen environments, methods to generate synthetic training data for data-driven discriminative methods, and robust optimisers to minimise the tracking objective. This thesis contributes (1) an automatic colour and depth image synthesis pipeline for data-driven learning without depending on a real articulated robot; (2) a training strategy for discriminative model-fitting objectives with an implicit representation of objects; (3) a tracking objective that is able to track occluded parts of a kinematic chain; and finally (4) a robust multi-hypotheses optimiser. These contributions are evaluated on two robotic platforms in different environments and with different manipulated and occluding objects. We demonstrate that our image synthesis pipeline generalises well to colour and depth observations of the real robot without requiring real ground truth labelled images. While this synthesis approach introduces a visual simulation-to-reality gap, the combination of our robust tracking objective and optimiser enables stable tracking of an occluded end-effector during manipulation tasks