344 research outputs found
Omineca Herald, March, 14, 1928
We conducted 46 interviews with CEOs and CFOs who were closely
involved in an initial public offering (IPO) in the Netherlands. Among other things, we
find that pre-existing relationships are a primary consideration in the selection of the
lead manager and other syndicate members. Pre-marketing feedback figures prominently
throughout the pricing process. The width of the price range of book-built IPOs
is especially driven by valuation uncertainty. There is evidence of strategic underpricing
in anticipation of subsequent equity issues and because of management’s interest
in satisfying new shareholders. Many interviewees believe that the lead manager’s
business interests have had a strong influence on the allocation of shares. Managerial
perceptions of IPO success are largely driven by how well the firm fared in terms of
stock price performance, changes in media attention and visibility, and changes related
to the retention and recruitment of staff
Hereditary complement factor I deficiency
Summary We describe four cases (from three families) of hereditary factor I deficiency, bringing the total number of cases now reported to 23. In one family there are two affected siblings: one has suffered recurrent pyogenic infections; the other is asymptomatic. In the second family, the patient had recurrent pyogenic infections and a self-limiting vasculitic illness; in the third family, the patient suffered recurrent pyogenic and neisserial infections. All four patients had markedly reduced concentrations of C3 in the serum (family 1 propositus: 28%; family 1 asymptomatic sibling: 15%; family 2: 31%; and family 3: 31 % normal human serum) which was in the form of C3b. Low lgG2 levels may occur in primary C3 deficiency, and reduction in lgG2 concentration to 1.14 g/l (normal: 1.30-5.90 g/l) was found in the patient from family 2. Using radioligand binding assays, we demonstrated increased binding of C3b to erythrocytes in a patient with factor I deficiency. This C3b could not be cleaved by autologous serum but could be cleaved by normal serum or purified factor I. We review and compare the published cases of C3, factor H and factor I deficienc
On the chirality of quark modes
A model for the QCD vacuum based on a domainlike structured background gluon
field with definite duality attributed to the domains has been shown elsewhere
to give confinement of static quarks, a reasonable value for the topological
susceptibility and indications that chiral symmetry is spontaneously broken. In
this paper we study in detail the eigenvalue problem for the Dirac operator in
such a gluon mean field. A study of the local chirality parameter shows that
the lowest nonzero eigenmodes possess a definite mean chirality correlated with
the duality of a given domain. A probability distribution of the local
chirality qualitatively reproduces histograms seen in lattice simulations.Comment: RevTeX4, 5 figures, 14 page
Trial-based cost-effectiveness analysis comparing surgical and endoscopic drainage in patients with obstructive chronic pancreatitis
Objective: Published evidence indicates that surgical drainage of the pancreatic duct was more effective than endoscopic drainage for patients with chronic pancreatitis. This analysis assessed the cost-effectiveness of surgical versus endoscopic drainage in obstructive chronic pancreatitis. Design: This trial-based cost-utility analysis (ISRCTN04572410) was conducted from a UK National Health Service (NHS) perspective and during a 79-month time horizon. During the trial the details of the diagnostic and therapeutic procedures, and pancreatic insufficiency were collected. The resource use was varied in the sensitivity analysis based on a review of the literature. The health outcome was the Quality-Adjusted Life Year (QALY), generated using EQ-5D data collected during the trial. There were no pancreas-related deaths in the trial. All-cause mortality from the trial was incorporated into the QALY estimates in the sensitivity analysis. Setting: Hospital. Participants: Patients with obstructive chronic pancreatitis. Primary and secondary outcome measures: Costs, QALYs and cost-effectiveness. Results: The result of the base-case analysis was that surgical drainage dominated endoscopic drainage, being both more effective and less costly. The sensitivity analysis varied mortality and resource use and showed that the surgical option remained dominant in all scenarios. The probability of cost-effectiveness for surgical drainage was 100% for the base case and 82% in the assessed most conservative case scenario. Conclusions: In obstructive chronic pancreatitis, surgical drainage is highly cost-effective compared with endoscopic drainage from a UK NHS perspective
Recentered importance sampling with applications to Bayesian model validation
Since its introduction in the early 1990s, the idea of using importance sampling (IS) with Markov chain Monte Carlo (MCMC) has found many applications. This article examines problems associated with its application to repeated evaluation of related posterior distributions with a particular focus on Bayesian model validation. We demonstrate that, in certain applications, the curse of dimensionality can be reduced by a simple modification of IS. In addition to providing new theoretical insight into the behavior of the IS approximation in a wide class of models, our result facilitates the implementation of computationally intensive Bayesian model checks. We illustrate the simplicity, computational savings, and potential inferential advantages of the proposed approach through two substantive case studies, notably computation of Bayesian p-values for linear regression models and simulation-based model checking. Supplementary materials including the Appendix and the R code for Section 3.1.2 are available online
First report of AURORA, the breast international group (BIG) molecular screening initiative for metastatic breast cancer (MBC) patients (pts)
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Construction of the Pauli-Villars-regulated Dirac vacuum in electromagnetic fields
Using the Pauli-Villars regularization and arguments from convex analysis, we
construct solutions to the classical time-independent Maxwell equations in
Dirac's vacuum, in the presence of small external electromagnetic sources. The
vacuum is not an empty space, but rather a quantum fluctuating medium which
behaves as a nonlinear polarizable material. Its behavior is described by a
Dirac equation involving infinitely many particles. The quantum corrections to
the usual Maxwell equations are nonlinear and nonlocal. Even if photons are
described by a purely classical electromagnetic field, the resulting vacuum
polarization coincides to first order with that of full Quantum
Electrodynamics.Comment: Final version to appear in Arch. Rat. Mech. Analysi
Collisional Velocities and Rates in Resonant Planetesimal Belts
We consider a belt of small bodies around a star, captured in one of the
external or 1:1 mean-motion resonances with a massive perturber. The objects in
the belt collide with each other. Combining methods of celestial mechanics and
statistical physics, we calculate mean collisional velocities and collisional
rates, averaged over the belt. The results are compared to collisional
velocities and rates in a similar, but non-resonant belt, as predicted by the
particle-in-a-box method. It is found that the effect of the resonant lock on
the velocities is rather small, while on the rates more substantial. The
collisional rates between objects in an external resonance are by about a
factor of two higher than those in a similar belt of objects not locked in a
resonance. For Trojans under the same conditions, the collisional rates may be
enhanced by up to an order of magnitude. Our results imply, in particular,
shorter collisional lifetimes of resonant Kuiper belt objects in the solar
system and higher efficiency of dust production by resonant planetesimals in
debris disks around other stars.Comment: 31 pages, 11 figures (some of them heavily compressed to fit into
arxiv-maximum filesize), accepted for publication at "Celestial Mechanics and
Dynamical Astronomy
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