Tri-N-ification

We consider a natural generalization of trinification to theories with 3N SU(3) gauge groups. These theories have a simple moose representation and a gauge boson spectrum that can be interpreted via the deconstruction of a 5D theory with unified symmetry broken on a boundary. Although the matter and Higgs sectors of the theory have no simple extra-dimensional analog, gauge unification retains features characteristic of the 5D theory. We determine possible assignments of the matter and Higgs fields to unified multiplets and present theories that are viable alternatives to minimal trinified GUTs.Comment: 21 pages LaTeX, 6 eps figure

Unusual High-Energy Phenomenology of Lorentz-Invariant Noncommutative Field Theories

It has been suggested that one may construct a Lorentz-invariant noncommutative field theory by extending the coordinate algebra to additional, fictitious coordinates that transform nontrivially under the Lorentz group. Integration over these coordinates in the action produces a four-dimensional effective theory with Lorentz invariance intact. Previous applications of this approach, in particular to a specific construction of noncommutative QED, have been studied only in a low-momentum approximation. Here we discuss Lorentz-invariant field theories in which the relevant physics can be studied without requiring an expansion in the inverse scale of noncommutativity. Qualitatively, we find that tree-level scattering cross sections are dramatically suppressed as the center-of-mass energy exceeds the scale of noncommutativity, that cross sections that are isotropic in the commutative limit can develop a pronounced angular dependence, and that nonrelativistic potentials (for example, the Coloumb potential) become nonsingular at the origin. We consider a number of processes in noncommutative QED that may be studied at a future linear collider. We also give an example of scattering via a four-fermion operator in which the noncommutative modifications of the interaction can unitarize the tree-level amplitude, without requiring any other new physics in the ultraviolet.Comment: 24 pages LaTeX, 4 eps figures (v2: reference added, v3: minor clarifications

Higgsless GUT Breaking and Trinification

Boundary conditions on an extra-dimensional interval can be chosen to break bulk gauge symmetries and to reduce the rank of the gauge group. We consider this mechanism in models with gauge trinification. We determine the boundary conditions necessary to break the trinified gauge group directly down to that of the standard model. Working in an effective theory for the gauge symmetry-breaking parameters on a boundary, we examine the limit in which the GUT-breaking sector is Higgsless and show how one may obtain the low-energy particle content of the minimal supersymmetric standard model. We find that gauge unification is preserved in this scenario, and that the differential gauge coupling running is logarithmic above the scale of compactification. We compare the phenomenology of our model to that of four-dimensional trinified theories.Comment: 22 pages, LaTeX, 2 eps figures (v3: discussion of mass scales clarified

Liver transplantation for arteriohepatic dysplasia (Alagille's syndrome)

Thirteen out of 268 children (<18 years old) underwent hepatic transplantation (OLT) for end-stage liver disease (ESLD) associated with arteriohepatic dysplasia (AHD). Seven children are alive and well with normal liver function. Six children died, four within 11 days of the operation and the other two at 4 and 10 months after the OLT. Vascular complications with associated septicemia were responsible for the deaths of three children. Two died of heart failure and circulatory collapse, secondary to pulmonary hypertension and congenital heart disease. The remaining patient died of overwhelming sepsis not associated with technical complications. Seven patients had a portoenterostomy or portocholecystostomy early in life; five of these died after the OLT. Severe cardiovascular abnormalities in some of our patients suggest that complete hemodynamic monitoring with invasive studies should be performed in all patients with AHD, especially in cases of documented hypertrophy of the right ventricle. The improved quality of life in our surviving patients confirms the validity of OLT as a treatment of choice in cases of ESLD due to AHD. © 1992 Springer-Verlag

Bacterial–viral load and the immune response in stable and exacerbated COPD: Significance and therapeutic prospects

Chronic obstructive pulmonary disease (COPD) is characterized by persistent airflow limitation and an abnormal inflammatory response of the lung. Bacteria and viruses are a major cause of COPD exacerbations and may contribute to COPD progression by perpetuating the inflammatory response in the airways. Bacterial variety diminishes with increasing COPD severity. Respiratory viruses can colonize the lower respiratory tract in stable COPD, altering the respiratory microbiome and facilitating secondary bacterial infections. In this review, we present the most updated information about the role of bacteria and viruses in stable and exacerbated COPD. In our opinion, to optimize therapeutic strategies, the dynamic events involving bacterial–viral infections and related immune response in COPD phenotypes need to be better clarified. Our paper would address these points that we consider of great importance for the clinical management of COPD

Symmetries of the Standard Model without and with a Right-Handed Neutrino

Given the particle content of the standard model without and with a right-handed neutrino, the requirement that all anomalies cancel singles out a set of possible global symmetries which can be gauged. I review this topic and propose a new gauge symmetry B - 3L_tau in the context of the minimal standard model consisting of the usual three families of quarks and leptons plus just one nu_R. The many interesting phenomenological consequences of this hypothesis are briefly discussed.Comment: 7 pages, no figure, latex, sprocl.sty, talk at the Fifth Workshop on High Energy Physics Phenomenology, Pune, Jan 9