Insulation from Liability through Subsidiary Corporations

While the desire for limited liability has played its part in increasing the use of the corporate device among the smaller industrial units, it alone is not responsible for such extensive use of the corporation arpong the larger industrial units. A primary factor there has been absentee ownership, attendant on the wide distribution of securities. The corporate device has lent itself peculiarly well to the public marketing of securities and to the evolution of a management structure in which the so-called owners play insignificant roles. The factor of limited liability has not been unimportant. It merely has not been paramount., The same can be said for the evolution that has taken place within the business units using the corporate form. Recent years especially have seen an increasing use of the subsidiaryparent structure. The farthest point along this line of evolution has been reached in the public utility field. But other businesses have adopted it and used it extensively. The reasons for the use of this structure are manifold. The increased facility in financing; the desire to escape the difficulty, if not the impossibility, of qualifying the parent company as a foreign corporation in a particular state; the avoidance of complicatinn.- involved in the purchase of physical assets: the raention of the good will of an established business unit; the avoidance of taxation; the avoidance of cumbersome management structures; the deb.. for limited liability, are among the primary motives. The desire for limited liability has been merely one among many factors. And at times it has appeared to recede

The supersymmetric modified Poschl-Teller and delta-well potentials

New supersymmetric partners of the modified Poschl-Teller and the Dirac's delta well potentials are constructed in closed form. The resulting one-parametric potentials are shown to be interrelated by a limiting process. The range of values of the parameters for which these potentials are free of singularities is exactly determined. The construction of higher order supersymmetric partner potentials is also investigated.Comment: 20 pages, LaTeX file, 4 eps figure

The optical system of the H.E.S.S. imaging atmospheric Cherenkov telescopes, Part II: mirror alignment and point spread function

Mirror facets of the H.E.S.S. imaging atmospheric Cherenkov telescopes are aligned using stars imaged onto the closed lid of the PMT camera, viewed by a CCD camera. The alignment procedure works reliably and includes the automatic analysis of CCD images and control of the facet alignment actuators. On-axis, 80% of the reflected light is contained in a circle of less than 1 mrad diameter. The spot widens with increasing angle to the telescope axis. In accordance with simulations, the spot size has roughly doubled at an angle of 1.4 degr. from the axis. The expected variation of spot size with elevation due to deformations of the support structure is visible, but is completely non-critical over the usual working range. Overall, the optical quality of the telescope exceeds the specifications.Comment: 23 pages, 13 figure

Exactly Solvable Hydrogen-like Potentials and Factorization Method

A set of factorization energies is introduced, giving rise to a generalization of the Schr\"{o}dinger (or Infeld and Hull) factorization for the radial hydrogen-like Hamiltonian. An algebraic intertwining technique involving such factorization energies leads to derive $n$-parametric families of potentials in general almost-isospectral to the hydrogen-like radial Hamiltonians. The construction of SUSY partner Hamiltonians with ground state energies greater than the corresponding ground state energy of the initial Hamiltonian is also explicitly performed.Comment: LaTex file, 21 pages, 2 PostScript figures and some references added. To be published in J. Phys. A: Math. Gen. (1998

Non-Perturbative QCD Treatment of High-Energy Hadron-Hadron Scattering

Total cross-sections and logarithmic slopes of the elastic scattering cross-sections for different hadronic processes are calculated in the framework of the model of the stochastic vacuum. The relevant parameters of this model, a correlation length and the gluon condensate, are determined from scattering data, and found to be in very good agreement with values coming from completely different sources of information. A parameter-free relation is given between total cross-sections and slope parameters, which is shown to be remarkably valid up to the highest energies for which data exist.Comment: 60 pages, Heidelberg preprin

PCR Improves Diagnostic Yield from Lung Aspiration in Malawian Children with Radiologically Confirmed Pneumonia

Accurate data on childhood pneumonia aetiology are essential especially from regions where mortality is high, in order to inform case-management guidelines and the potential of prevention strategies such as bacterial conjugate vaccines. Yield from blood culture is low, but lung aspirate culture provides a higher diagnostic yield. We aimed to determine if diagnostic yield could be increased further by polymerase chain reaction (PCR) detection of bacteria (Streptococcus pneumoniae and Haemophilus influenzae b) and viruses in lung aspirate fluid.A total of 95 children with radiological focal, lobar or segmental consolidation had lung aspirate performed and sent for bacterial culture and for PCR for detection of bacteria, viruses and Pneumocystis jirovecii. In children with a pneumococcal aetiology, pneumococcal bacterial loads were calculated in blood and lung aspirate fluid.Blood culture identified a bacterial pathogen in only 8 patients (8%). With the addition of PCR on lung aspirate samples, causative pathogens (bacterial, viral, pneumocystis) were identified singly or as co-infections in 59 children (62%). The commonest bacterial organism was S.pneumoniae (41%), followed by H. influenzae b (6%), and the commonest virus identified was adenovirus (16%), followed by human bocavirus (HBoV) (4%), either as single or co-infection.In a select group of African children, lung aspirate PCR significantly improves diagnostic yield. Our study confirms a major role of S.pneumoniae and viruses in the aetiology of childhood pneumonia in Africa

Non-vacuum Solutions of Bianchi Type VI_0 Universe in f(R) Gravity

In this paper, we solve the field equations in metric f(R) gravity for Bianchi type VI_0 spacetime and discuss evolution of the expanding universe. We find two types of non-vacuum solutions by taking isotropic and anisotropic fluids as the source of matter and dark energy. The physical behavior of these solutions is analyzed and compared in the future evolution with the help of some physical and geometrical parameters. It is concluded that in the presence of isotropic fluid, the model has singularity at $\tilde{t}=0$ and represents continuously expanding shearing universe currently entering into phantom phase. In anisotropic fluid, the model has no initial singularity and exhibits the uniform accelerating expansion. However, the spacetime does not achieve isotropy as $t\rightarrow\infty$ in both of these solutions.Comment: 20 pages, 5 figures, accepted for publication in Astrophys. Space Sc

Space-based research in fundamental physics and quantum technologies

Space-based experiments today can uniquely address important questions related to the fundamental laws of Nature. In particular, high-accuracy physics experiments in space can test relativistic gravity and probe the physics beyond the Standard Model; they can perform direct detection of gravitational waves and are naturally suited for precision investigations in cosmology and astroparticle physics. In addition, atomic physics has recently shown substantial progress in the development of optical clocks and atom interferometers. If placed in space, these instruments could turn into powerful high-resolution quantum sensors greatly benefiting fundamental physics. We discuss the current status of space-based research in fundamental physics, its discovery potential, and its importance for modern science. We offer a set of recommendations to be considered by the upcoming National Academy of Sciences' Decadal Survey in Astronomy and Astrophysics. In our opinion, the Decadal Survey should include space-based research in fundamental physics as one of its focus areas. We recommend establishing an Astronomy and Astrophysics Advisory Committee's interagency ``Fundamental Physics Task Force'' to assess the status of both ground- and space-based efforts in the field, to identify the most important objectives, and to suggest the best ways to organize the work of several federal agencies involved. We also recommend establishing a new NASA-led interagency program in fundamental physics that will consolidate new technologies, prepare key instruments for future space missions, and build a strong scientific and engineering community. Our goal is to expand NASA's science objectives in space by including ``laboratory research in fundamental physics'' as an element in agency's ongoing space research efforts.Comment: a white paper, revtex, 27 pages, updated bibliograph