Minority Economic Development: The Problem of Business Failures

Inflammatory pseudotumour is a rare condition that can affect various organs. The clinical and histologic appearance of the pseudotumour may mimic haematological, lymphoproliferative, paraneoplastic or malignant processes. A previously healthy 39-year-old man presented with nephrotic syndrome. He had a history of headaches, nausea and swollen ankles. Computed tomography of the abdomen revealed a 6-cm mass in the spleen. Following a renal biopsy, a diagnosis of membranoproliferative glomerulonephritis (MPGN) type I was made. Splenectomy was performed and the examination revealed a mixed population of lymphocytes with predominantly T-cells, B-cells and lymphoplasmacytoid cells. Immunostaining confirmed that the small cells were mostly T-cells positive for all T-cell markers including CD2, CD3, CD4, CD5, CD7 and CD8. A diagnosis of inflammatory pseudotumour was established. The removal of the spleen was followed by remission of glomerulonephritis, but it was complicated by a subphrenic abscess and pneumonia. This association between an inflammatory pseudotumour of the spleen and MPGN has not been previously described. Abnormal immune response due to the inflammation leading to secondary glomerulonephritis might be the main pathogenic mechanism

Effects of Preference for Attachment to Low-degree Nodes on the Degree Distributions of a Growing Directed Network and a Simple Food-Web Model

We study the growth of a directed network, in which the growth is constrained by the cost of adding links to the existing nodes. We propose a new preferential-attachment scheme, in which a new node attaches to an existing node i with probability proportional to 1/k_i, where k_i is the number of outgoing links at i. We calculate the degree distribution for the outgoing links in the asymptotic regime (t->infinity), both analytically and by Monte Carlo simulations. The distribution decays like k c^k/Gamma(k) for large k, where c is a constant. We investigate the effect of this preferential-attachment scheme, by comparing the results to an equivalent growth model with a degree-independent probability of attachment, which gives an exponential outdegree distribution. Also, we relate this mechanism to simple food-web models by implementing it in the cascade model. We show that the low-degree preferential-attachment mechanism breaks the symmetry between in- and outdegree distributions in the cascade model. It also causes a faster decay in the tails of the outdegree distributions for both our network growth model and the cascade model.Comment: 10 pages, 7 figures. A new figure added. Minor modifications made in the tex

Magnetic field-induced soft mode in spin-gapped high-Tc superconductors

We present an explanation of the dynamical in-gap spin mode in LSCO induced by an applied magnetic field H as recently observed by J. Chang et al. Our model consists of a phenomenological spin-only Hamiltonian, and the softening of the spin mode is caused by vortex pinning of dynamical stripe fluctuations which we model by a local ordering of the exchange interactions. The spin gap vanishes experimentally around H=7T which in our scenario corresponds to the field required for overlapping vortex regions.Comment: 4 pages, 3 fig

Structure and binding in crystals of cage-like molecules: hexamine and platonic hydrocarbons

In this paper, we show that first-principle calculations using a van der Waals density functional (vdW-DF), [Phys. Rev. Lett. $\mathbf{92}$, 246401 (2004)] permits determination of molecular crystal structure. We study the crystal structures of hexamine and the platonic hydrocarbons (cubane and dodecahedrane). The calculated lattice parameters and cohesion energy agree well with experiments. Further, we examine the asymptotic accounts of the van der Waals forces by comparing full vdW-DF with asymptotic atom-based pair potentials extracted from vdW-DF. The character of the binding differ in the two cases, with vdW-DF giving a significant enhancement at intermediate and relevant binding separations. We analyze consequences of this result for methods such as DFT-D, and question DFT-D's transferability over the full range of separations

Encoding the scaling of the cosmological variables with the Euler Beta function

We study the scaling exponents for the expanding isotropic flat cosmological models. The dimension of space, the equation of state of the cosmic fluid and the scaling exponent for a physical variable are related by the Euler Beta function that controls the singular behavior of the global integrals. We encounter dual cosmological scenarios using the properties of the Beta function. For the entropy density integral we reproduce the Fischler-Susskind holographic bound.Comment: Latex2e, 11 pages, 1 figure; reference added; minor changes commenting the nature of the holographic principle and the particle/event horizo

The dissociation energy of N2

The requirements for very accurate ab initio quantum chemical prediction of dissociation energies are examined using a detailed investigation of the nitrogen molecule. Although agreement with experiment to within 1 kcal/mol is not achieved even with the most elaborate multireference CI (configuration interaction) wave functions and largest basis sets currently feasible, it is possible to obtain agreement to within about 2 kcal/mol, or 1 percent of the dissociation energy. At this level it is necessary to account for core-valence correlation effects and to include up to h-type functions in the basis. The effect of i-type functions, the use of different reference configuration spaces, and basis set superposition error were also investigated. After discussing these results, the remaining sources of error in our best calculations are examined

Supercritical Water Gasification: Practical Design Strategies and Operational Challenges for Lab-Scale, Continuous Flow Reactors

Optimizing an industrial-scale supercritical water gasification process requires detailed knowledge of chemical reaction pathways, rates, and product yields. Laboratory-scale reactors are employed to develop this knowledge base. The rationale behind designs and component selection of continuous flow, laboratory-scale supercritical water gasification reactors is analyzed. Some design challenges have standard solutions, such as pressurization and preheating, but issues with solid precipitation and feedstock pretreatment still present open questions. Strategies for reactant mixing must be evaluated on a system-by-system basis, depending on feedstock and experimental goals, as mixing can affect product yields, char formation, and reaction pathways. In-situ Raman spectroscopic monitoring of reaction chemistry promises to further fundamental knowledge of gasification and decrease experimentation time. High-temperature, high-pressure spectroscopy in supercritical water conditions is performed, however, long-term operation flow cell operation is challenging. Comparison of Raman spectra for decomposition of formic acid in the supercritical region and cold section of the reactor demonstrates the difficulty in performing quantitative spectroscopy in the hot zone. Future designs and optimization of SCWG reactors should consider well-established solutions for pressurization, heating, and process monitoring, and effective strategies for mixing and solids handling for long-term reactor operation and data collection

A Simple Derivation of the Hard Thermal Loop Effective Action

We use the background field method along with a special gauge condition, to derive the hard thermal loop effective action in a simple manner. The new point in the paper is to relate the effective action explicitly to the S-matrix from the onset.Comment: 11 pages, Latex; lost text after sect. 2 reinserte

Weak Gravitational Lensing by a Sample of X-Ray Luminous Clusters of Galaxies -- II. Comparison with Virial Masses

Dynamic velocity dispersion and mass estimates are given for a sample of five X-ray luminous rich clusters of galaxies at intermediate redshifts (z~0.3) drawn from a sample of 39 clusters for which we have obtained gravitational lens mass estimates. The velocity dispersions are determined from between 9 and 20 redshifts measured with the LDSS spectrograph of the William Herschel Telescope, and virial radii are determined from imaging using the UH8K mosaic CCD camera on the University of Hawaii 2.24m telescope. Including clusters with velocity dispersions taken from the literature, we have velocity dispersion estimates for 12 clusters in our gravitational lensing sample. For this sample we compare the dynamical velocity dispersion estimates with our estimates of the velocity dispersions made from gravitational lensing by fitting a singular isothermal sphere profile to the observed tangential weak lensing distortion as a function of radius. In all but two clusters, we find a good agreement between the velocity dispersion estimates based on spectroscopy and on weak lensing.Comment: 9 pages, 4 figures, accepted for publication in ApJ. Version in emulateapj format with only minor change