Planck Oscillators in the Background Dark Energy

We consider a model for an underpinning of the universe: there are oscillators at the Planck scale in the background dark energy. Starting from a coherent array of such oscillators it is possible to get a description from elementary particles to Black Holes including the usual Hawking-Beckenstein theory. There is also a description of Gravitation in the above model which points to a unified description with electromagnetism.Comment: 18 pages latex; talk at the Max Born Symposium 2009, Wrocla

Distribution of MHC class II alleles in primary systemic vasculitis

Distribution of MHC class II alleles in primary systemic vasculitis. Previous studies have shown a number of different associations between major histocompatibility complex (MHC) alleles and primary systemic vasculitis. Disease heterogeneity and the lack of specificity of certain MHC typing techniques may have contributed to the lack of consistency in those studies. We therefore studied a relatively homogeneous group of 94 patients with Wegener's granulomatosis, microscopic polyangiitis, or renal-limited vasculitis using molecular techniques that allow more precise assignment of MHC genotype. DNA was prepared from peripheral blood and DRB1 genotype determined by Taq restriction fragment length polymorphism. DQB1 and DPB1 genotype were assigned by polymerase chain reaction amplification followed by probing with allele-specific oligonucleotides. Specificity of associated anti-neutrophil cytoplasm antibodies (ANCA) was determined where possible by solid phase immunoassays using purified proteinase 3 (PR3) and myeloperoxidase (MPO). After correction for multiple comparisons there were no significant differences in the distribution of DRB1, DQB1 and DPB1 alleles between a local control group (N = 90 for DRB1, N = 50 for DQB1 and DPB1) and the patient group as a whole (N = 94) or two a priori defined subgroups (anti-PR3 positive, N = 35; anti-MPO positive, N = 22). We have therefore found no significant association between primary systemic vasculitis and any MHC class II allele. This, together with the fact that previous smaller studies have shown no consistent association, suggests that any such association is very weak, if it exists at all

Cirugía de la fibrilación auricular

Atrial fibrillation surgery is based on creating scars in the atrium, in order to avoid re-entry phenomena that may initiate and perpetuate arrhythmia, and driving the normal stimuli from the sinus node to the atrio-ventricular node. The complexity and increased risk of the initial surgical technique, based on a "cut-and-sew" procedure, have enhanced other current procedures, in which different energies are used making it possible to perform scars in a safer and less invasive way. At present, atrial fibrillation surgery is not performed routinely in all cardiothoracic surgical centers, and there is no consensus in which is the best type of technique. Even if the results are good, they depend on multiples factors such as duration of arrhythmia, atrial size and type of technique employed. In addition, there is some variability in the description within the scientific community of the results and procedures used, which makes its analysis confusing. In this paper we review the different techniques described, the results and their application in minimally invasive surgery

Mapping aerial metal deposition in metropolitan areas from tree bark : a case study in Sheffield, England

We investigated the use of metals accumulated on tree bark for mapping their deposition across metropolitan Sheffield by sampling 642 trees of three common species. Mean concentrations of metals were generally an order of magnitude greater than in samples from a remote uncontaminated site. We found trivially small differences among tree species with respect to metal concentrations on bark, and in subsequent statistical analyses did not discriminate between them. We mapped the concentrations of As, Cd and Ni by lognormal universal kriging using parameters estimated by residual maximum likelihood ({\sc reml}). The concentrations of Ni and Cd were greatest close to a large steel works, their probable source, and declined markedly within 500~metres of it and from there more gradually over several kilometres. Arsenic was much more evenly distributed, probably as a result of locally mined coal burned in domestic fires for many years. Tree bark seems to integrate airborne pollution over time, and our findings show that sampling and analysing it are cost-effective means of mapping and identifying sources

Using grounded theory method in information systems: The researcher as blank slate and other myths

The use of grounded theory method (GTM) as a research method in information systems (IS) has gradually increased over the years as qualitative research in general has become more prevalent. The method offers a systematic way to generate theory from data, but is rarely used to its full potential in IS as a number of myths and misunderstandings about GTM prevent researchers from getting the full potential out of the method. To address this problem, we advance the general level of knowledge of GTM. We clarify aspects of the method that are often misunderstood by novice users or casual observers and provide guidance to address common problems. Exemplars from the IS literature are used to illustrate the concepts and to promote the informed use of the methodology. By doing so, this paper will contribute to improving the use of the method and to the quality and dissemination of grounded theory research outcomes. © 2013 JIT Palgrave Macmillan All rights reserved

Pion Content of the Nucleon as seen in the NA51 Drell-Yan experiment

In a recent CERN Drell-Yan experiment the NA51 group found a strong asymmetry of $\bar u$ and $\bar d$ densities in the proton at $x\simeq0.18$. We interpret this result as a decisive confirmation of the pion-induced sea in the nucleon.Comment: 10 pages + 3 figures, Preprint KFA-IKP(TH)-1994-14 .tex file. After \enddocument a uu-encodeded Postscript file comprising the figures is appende

Comments on gluon scattering amplitudes via AdS/CFT

In this article we consider n gluon color ordered, planar amplitudes in N=4 super Yang Mills at strong 't Hooft coupling. These amplitudes are approximated by classical surfaces in AdS_5 space. We compute the value of the amplitude for a particular kinematic configuration for a large number of gluons and find that the result disagrees with a recent guess for the exact value of the amplitude. Our results are still compatible with a possible relation between amplitudes and Wilson loops. In addition, we also give a prescription for computing processes involving local operators and asymptotic states with a fixed number of gluons. As a byproduct, we also obtain a string theory prescription for computing the dual of the ordinary Wilson loop, Tr P exp[ i\oint A ], with no couplings to the scalars. We also evaluate the quark-antiquark potential at two loops.Comment: 27 pages, 9 figures,v3:minor correction

A Dendritic Cell–Specific Intercellular Adhesion Molecule 3–Grabbing Nonintegrin (Dc-Sign)–Related Protein Is Highly Expressed on Human Liver Sinusoidal Endothelial Cells and Promotes HIV-1 Infection

The discovery of dendritic cell (DC)-specific intercellular adhesion molecule (ICAM)-3–grabbing nonintegrin (DC-SIGN) as a DC-specific ICAM-3 binding receptor that enhances HIV-1 infection of T cells in trans has indicated a potentially important role for adhesion molecules in AIDS pathogenesis. A related molecule called DC-SIGNR exhibits 77% amino acid sequence identity with DC-SIGN. The DC-SIGN and DC-SIGNR genes map within a 30-kb region on chromosome 19p13.2-3. Their strong homology and close physical location indicate a recent duplication of the original gene. Messenger RNA and protein expression patterns demonstrate that the DC-SIGN–related molecule is highly expressed on liver sinusoidal cells and in the lymph node but not on DCs, in contrast to DC-SIGN. Therefore, we suggest that a more appropriate name for the DC-SIGN–related molecule is L-SIGN, liver/lymph node–specific ICAM-3–grabbing nonintegrin. We show that in the liver, L-SIGN is expressed by sinusoidal endothelial cells. Functional studies indicate that L-SIGN behaves similarly to DC-SIGN in that it has a high affinity for ICAM-3, captures HIV-1 through gp120 binding, and enhances HIV-1 infection of T cells in trans. We propose that L-SIGN may play an important role in the interaction between liver sinusoidal endothelium and trafficking lymphocytes, as well as function in the pathogenesis of HIV-1

Deletion and duplication of DNA sequences is associated with the embryonic lethal phenotype of the t9 complementation group of the mouse t complex.

We have analyzed the genomic structure of three mouse t haplotypes of the t9 complementation group. Each of these t haplotypes, tw18, t4, and tks1, is known to have resulted from a rare recombination event between a complete t haplotype and a wild-type chromosome. Using molecular probes that identify sequences in the distal portion of the t complex, we have shown that each of these t haplotypes contains a similar (perhaps identical) deletion of one group of t complex sequences, and duplication of another group. These data suggest that the recombination events that produced these three t haplotypes involved similar unequal crossovers within the distal inversion. The deletion and duplication of genetic material associated with all members of the t9 complementation group tested provides a molecular explanation for the recessive lethal mutation associated with these t haplotypes

Local densities, distribution functions, and wave function correlations for spatially resolved shot noise at nanocontacts

We consider a current-carrying, phase-coherent multi-probe conductor to which a small tunneling contact is attached. We treat the conductor and the tunneling contact as a phase-coherent entity and use a Green's function formulation of the scattering approach. We show that the average current and the current fluctuations at the tunneling contact are determined by an effective local non-equilibrium distribution function. This function characterizes the distribution of charge-carriers (or quasi-particles) inside the conductor. It is an exact quantum-mechanical expression and contains the phase-coherence of the particles via local partial densities of states, called injectivities. The distribution function is analyzed for different systems in the zero-temperature limit as well as at finite temperature. Furthermore, we investigate in detail the correlations of the currents measured at two different contacts of a four-probe sample, where two of the probes are only weakly coupled contacts. In particular, we show that the correlations of the currents are at zero-temperature given by spatially non-diagonal injectivities and emissivities. These non-diagonal densities are sensitive to correlations of wave functions and the phase of the wave functions. We consider ballistic conductors and metallic diffusive conductors. We also analyze the Aharonov-Bohm oscillations in the shot noise correlations of a conductor which in the absence of the nano-contacts exhibits no flux-sensitivity in the conductance.Comment: 17 pages, 8 figure