2,129 research outputs found
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. --
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. Inputâoutput 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
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
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
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
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.
The Pavlik Harness in the Treatment of Congenital Dislocating Hip: Report on a Multicenter Study of the European Paediatric Orthopaedic Society
The results of functional treatment using the Pavlik harness in congenital
dislocation and congenital dysplasia of the hip in children aged less than 11
months were examined by an EPOS study group. This study was conducted on 3,611
hips in 2,636 patients for a period of 1-9 years after treatment. The reduction
rate was 92% in grade Tonnis 2 and 3; the healing rate was 80%. In children with
dysplastic hips, the healing rate was 95.35%. Avascular necrosis of the femoral
head was observed in 2.38%. The Pavlik harness is designed for outpatient
treatment if the parents are complian
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