3,188 research outputs found
Business strategy and firm performance: the British corporate economy, 1949-1984
There has been considerable and ongoing debate about the performance of the British economy since 1945. Empirical studies have concentrated on aggregate or industry level indicators. Few have examined individual firmsâ financial performance. This study takes a sample of c.3000 firms in 19 industries and identifies Britainâs best performing companies over a period of 35 years. Successful companies are defined as a) those that survive as independent entities, b) that outperform peer group average return to capital for that industry, and c) that outperform other firms in the economy according to return on capital relative to industry average. Results are presented as league tables of success and some tentative explanations offered concerning the common strategies of successful firms. A broader research agenda for British business history is suggested
A diagnostic plot for assessing model fit incount data models
Whilst many numeric methods, such as AIC and deviance, exist for assessing model fit, diagrammatic methods are few. We present here a diagnostic plot, to which we refer as âChristmas tree plotâ due its characteristic shape, that may be used to visually assess the suitability of a given count data model
On statistical testing and mean parameter estimation for zeroâmodification in count data regression
For the problem of testing for zeroâmodification in Poisson regression, a simple and intuitive test can be constructed by computing directly confidence intervals for the number of 0âs under the Poisson assumption. This requires the ability of estimating the mean function accurately even if the data are in fact zeroâinflated or deflated. A novel hybrid estimator is introduced for this purpose, which is of interest beyond the scope of the motivating test problem
A diagnostic plot for assessing model fit in count data models
Whilst many numeric methods, such as AIC and deviance, exist for assessing model fit, diagrammatic methods are few. We present here a diagnostic plot, to which we refer as `Christmas tree plot' due its characteristic shape, that may be used to visually assess the suitability of a given count data model
Immunocytochemical localization of protein kinase C in resting and activated human neutrophils
AbstractAn immunocytochemical method was used to determine possible changes in the subcellular distribution of protein kinase C (PKC) in human neutrophils in response to opsonized latex beads and zymosan. While in resting cells most of the PKC immunoreactivity was localized in the cytoplasm, a redistribution of PKC to the plasma and phagosomal membranes was observed in cells treated with latex beads or zymosan for 5â20 min, suggesting a participation of PKC in endocytosis
Pulmonary Hydatid Cyst with Complicating Aspergillus Infection Presenting as a Refractory Lung Abscess
Background Hydatid disease is rare in the United States. Rarely the hydatid cyst can become infected with mycotic organisms, such as Aspergillus . We describe a young male who presents with clinical features of suppurative lung abscess whose workup diagnosed hydatid cyst complicated by Aspergillus co-infection. Case presentation A 27-year-old Peruvian male was hospitalized because of fever, chills, and productive cough of three monthsâ duration. Clinical features were consistent with a suppurative lung abscess. Significant findings included leukocytosis with eosinophilia and a chest x-ray showing a large lingular lobe thick walled cavity with a wavy irregular fluid level. The patient ultimately underwent surgical resection of the lingular lobe. Examination of the surgical specimen revealed the cavity to be a hydatid cyst. Histologic examination of the cyst wall showed intense inflammation and several septate hyphae of Aspergillus species. The patient recovered fully and has remained in good health. Conclusion A thick-walled cavity and a wavy meniscus constitute unusual features for an ordinary pyogenic lung abscess and suggests other possibilities. Endogenous cases of hydatid disease are uncommon in the United States, with the majority of cases occurring in immigrants. There are few published case reports describing incidental findings of Aspergillus in a hydatid cyst. The rare occurrence of such a condition can lead to a delay in diagnosis and treatment
Extensions of discrete classical orthogonal polynomials beyond the orthogonality
It is well known that the family of Hahn polynomials
is orthogonal with respect to a certain
weight function up to . In this paper we present a factorization for Hahn
polynomials for a degree higher than and we prove that these polynomials
can be characterized by a -Sobolev orthogonality.
We also present an analogous result for dual-Hahn, Krawtchouk, and Racah
polynomials and give the limit relations between them for all n\in \XX N_0.
Furthermore, in order to get this results for the Krawtchouk polynomials we
will get a more general property of orthogonality for Meixner polynomials.Comment: 2 figures, 20 page
Potential for Supernova Neutrino Detection in MiniBooNE
The MiniBooNE detector at Fermilab is designed to search for oscillation appearance at and to make a
decisive test of the LSND signal. The main detector (inside a veto shield) is a
spherical volume containing 0.680 ktons of mineral oil. This inner volume,
viewed by 1280 phototubes, is primarily a \v{C}erenkov medium, as the
scintillation yield is low. The entire detector is under a 3 m earth
overburden. Though the detector is not optimized for low-energy (tens of MeV)
events, and the cosmic-ray muon rate is high (10 kHz), we show that MiniBooNE
can function as a useful supernova neutrino detector. Simple trigger-level cuts
can greatly reduce the backgrounds due to cosmic-ray muons. For a canonical
Galactic supernova at 10 kpc, about 190 supernova
events would be detected. By adding MiniBooNE to the international network of
supernova detectors, the possibility of a supernova being missed would be
reduced. Additionally, the paths of the supernova neutrinos through Earth will
be different for MiniBooNE and other detectors, thus allowing tests of
matter-affected mixing effects on the neutrino signal.Comment: Added references, version to appear in PR
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