Resource-based theory and mergers & acquisitions success

Mergers & acquisitions (M&A) are most popular external growth strategies. While the number of M&A has been increasing during the past decades, on average, only the shareholders of target firms gain value during the acquisitions process, while acquirers do not receive abnormal positive returns. This paper analyses the impact of strategically valuable resources on the success of M&A decisions. We test complementary resource-based hypotheses regarding the value of M&A for the shareholders of both transaction partners. Our sample consists of transactions in the pharmaceutical and biotechnological industry. The results of our study show that the shareholders of both transaction partners will gain above average positive returns only when the acquirer and the target own and combine strategically valuable resources and capabilities. --

Determining physical properties of the cell cortex

Actin and myosin assemble into a thin layer of a highly dynamic network underneath the membrane of eukaryotic cells. This network generates the forces that drive cell and tissue-scale morphogenetic processes. The effective material properties of this active network determine large-scale deformations and other morphogenetic events. For example,the characteristic time of stress relaxation (the Maxwell time)in the actomyosin sets the time scale of large-scale deformation of the cortex. Similarly, the characteristic length of stress propagation (the hydrodynamic length) sets the length scale of slow deformations, and a large hydrodynamic length is a prerequisite for long-ranged cortical flows. Here we introduce a method to determine physical parameters of the actomyosin cortical layer (in vivo). For this we investigate the relaxation dynamics of the cortex in response to laser ablation in the one-cell-stage {\it C. elegans} embryo and in the gastrulating zebrafish embryo. These responses can be interpreted using a coarse grained physical description of the cortex in terms of a two dimensional thin film of an active viscoelastic gel. To determine the Maxwell time, the hydrodynamic length and the ratio of active stress and per-area friction, we evaluated the response to laser ablation in two different ways: by quantifying flow and density fields as a function of space and time, and by determining the time evolution of the shape of the ablated region. Importantly, both methods provide best fit physical parameters that are in close agreement with each other and that are similar to previous estimates in the two systems. We provide an accurate and robust means for measuring physical parameters of the actomyosin cortical layer.It can be useful for investigations of actomyosin mechanics at the cellular-scale, but also for providing insights in the active mechanics processes that govern tissue-scale morphogenesis.Comment: 17 pages, 4 figure

Resource-based theory and mergers & acquisitions success

Mergers & acquisitions (M&A;) are most popular external growth strategies. While the number of M&A; has been increasing during the past decades, on average, only the shareholders of target firms gain value during the acquisitions process, while acquirers do not receive abnormal positive returns. This paper analyses the impact of strategically valuable resources on the success of M&A; decisions. We test complementary resource-based hypotheses regarding the value of M&A; for the shareholders of both transaction partners. Our sample consists of transactions in the pharmaceutical and biotechnological industry. The results of our study show that the shareholders of both transaction partners will gain above average positive returns only when the acquirer and the target own and combine strategically valuable resources and capabilities

Analysis of High-Perimeter Planar Electrodes for Efficient Neural Stimulation

Planar electrodes are used in epidural spinal cord stimulation and epidural cortical stimulation. Electrode geometry is one approach to increase the efficiency of neural stimulation and reduce the power required to produce the level of activation required for clinical efficacy. Our hypothesis was that electrode geometries that increased the variation of current density on the electrode surface would increase stimulation efficiency. High-perimeter planar disk electrodes were designed with sinuous (serpentine) variation in the perimeter. Prototypes were fabricated that had equal surface areas but perimeters equal to two, three or four times the perimeter of a circular disk electrode. The interface impedance of high-perimeter prototype electrodes measured in vitro did not differ significantly from that of the circular electrode over a wide range of frequencies. Finite element models indicated that the variation of current density was significantly higher on the surface of the high-perimeter electrodes. We quantified activation of 100 model axons randomly positioned around the electrodes. Input–output curves of the percentage of axons activated as a function of stimulation intensity indicated that the stimulation efficiency was dependent on the distance of the axons from the electrode. The high-perimeter planar electrodes were more efficient at activating axons a certain distance away from the electrode surface. These results demonstrate the feasibility of increasing stimulation efficiency through the design of novel electrode geometries

Clinical Characteristics and Outcomes Among Individuals With Spinal Implant Infections: A Descriptive Study.

Little is known about the clinical presentation and outcomes associated with spinal implant infections. Here, we describe a single center's experience in a retrospective cohort of 109 individuals with spinal implant infections, including clinical, microbiological, therapeutic, and outcome data

PROPRIETA' DELLA MATERIA SUPERFLUIDA IN PRESENZA DEL RETICOLO NUCLEARE NELLA CROSTA INTERNA DELLE STELLE DI NEUTRONI

In this thesis I study three different properties of superfluid nuclear matter in the inner crust of neutron stars, which is formed by nuclear clusters immersed in a superfluid neutron gas and ultrarelativistic electrons. In the first part the cluster structure is calculated in the self-consistent HFB approach at zero temperature. The mean field and the pairing correlations of the inner crust nuclear matter are described, respectively, by a Skyrme-type effective interaction and by a zero range density dependent pairing force. The inner crust matter is treated in the Wigner-Seitz approximation. The properties of the Wigner-Seitz cells, i.e., their neutron to proton ratio and their radius at a given baryonic density, are obtained from the energy minimization at beta equilibrium. We have found that the Wigner-Seitz cells have a much smaller number of protons compared to the previous HF or HF+BCS calculations. In the second part the specific heat of the nuclear matter is calculated with the same HFB formalism used in the first part, but at finite temperature. This study represent a considerable improvement respect to the specific heats that are generally used in the literature on which the superfluid corrections to the specific heat were calculated in the BCS approach and considering the matter as homogeneous neutron gas. Using the HFB approach, in fact, it is possible to calculate directly the specific heat of the nuclear matter considering at the same time the composition, the interaction between particles, the clusters structure and the pairing properties. We have then used this specific heat in the study of the thermalization process in the cooling of a neutron star and we have found that the nuclear clusters have a non-negligible influence on the time evolution of the surface temperature of neutron stars. Finally, in the third part we have used numerical simulations of interaction of vortex with lattice to study the pinning force per unit length that binds a vortex to the nuclear lattice, one of the most important quantities in the vortex model for pulsar glitches, i.e. sudden variation of the rotation velocity of some neutron stars. The forces that we have found are almost two order of magnitude smaller than those reported in the literature and of the same order of those that have been suggested to explain the peculiar behaviour of real pulsar glitches. They can thus be applied in a quantitative model of the vortex dynamics in order to reproduce those phenomena

Thermalisation time and specific heat of neutron stars crust

We discuss the thermalisation process of the neutron stars crust described by solving the heat transport equation with a microscopic input for the specific heat of baryonic matter. The heat equation is solved with initial conditions specific to a rapid cooling of the core. To calculate the specific heat of inner crust baryonic matter, i.e., nuclear clusters and unbound neutrons, we use the quasiparticle spectrum provided by the Hartree-Fock-Bogoliubov approach at finite temperature. In this framework we analyse the dependence of the crust thermalisation on pairing properties and on cluster structure of inner crust matter. It is shown that the pairing correlations reduce the crust thermalisation time by a very large fraction. The calculations show also that the nuclear clusters have a non-negligible influence on the time evolution of the surface temperature of the neutron star.Comment: 7 pages, 5 figures, submitted to Phys. Rev.

Neonatal hearing screening: modelling cost and effectiveness of hospital- and community-based screening

This is the final version of the article. Available from the publisher via the DOI in this record.BACKGROUND: Children with congenital hearing impairment benefit from early detection and management of their hearing loss. These and related considerations led to the recommendation of universal newborn hearing screening. In 2001 the first phase of a national Newborn Hearing Screening Programme (NHSP) was implemented in England. Objective of this study was to assess costs and effectiveness for hospital and community-based newborn hearing screening systems in England based on data from this first phase with regard to the effects of alterations to parameter values. METHODS: DESIGN: Clinical effectiveness analysis using a Markov Model. OUTCOME MEASURE: quality weighted detected child months (QCM). RESULTS: Both hospital and community programmes yielded 794 QCM at the age of 6 months with total costs of 3,690,000 pound sterling per 100,000 screened children in hospital and 3,340,000 pound sterling in community. Simulated costs would be lower in hospital in 48% of the trials. Any statistically significant difference between hospital and community in prevalence, test sensitivity, test specificity and costs would result in significant differences in cost-effectiveness between hospital and community. CONCLUSION: This modelling exercise informs decision makers by a quantitative projection of available data and the explicit and transparent statements about assumptions and the degree of uncertainty. Further evaluation of the cost-effectiveness should focus on the potential differences in test parameters and prevalence in these two settings.This work was undertaken by the Evaluation Team for the Implementation Pilot of Newborn Hearing Screening in England which received funding from the Department of Health