Non-Canonical MSSM, Unification, And New Particles At The LHC

We consider non-canonical embeddings of the MSSM in high-dimensional orbifold GUTs based on the gauge symmetry SU(N), N=5,6,7,8. The hypercharge normalization factor k_Y can either have unique non-canonical values, such as 23/21 in a six-dimensional SU(7) model, or may lie in a (continuous) interval. Gauge coupling unification and gauge-Yukawa unification can be realized in these models by introducing new particles with masses in the TeV range which may be found at the LHC. In one such example there exist color singlet fractionally charged states.Comment: 1+25 pages, 5 figures. v2: Introduction revised, sections reordered, figure 4 correcte

Interference and Deployment Issues for Cognitive Radio Systems in Shadowing Environments

In this paper we describe a model for calculating the aggregate interference encountered by primary receivers in the presence of randomly placed cognitive radios (CRs). We show that incorporating the impact of distance attenuation and lognormal fading on each constituent interferer in the aggregate, leads to a composite interference that cannot be satisfactorily modeled by a lognormal. Using the interference statistics we determine a number of key parameters needed for the deployment of CRs. Examples of these are the exclusion zone radius, needed to protect the primary receiver under different types of fading environments and acceptable interference levels, and the numbers of CRs that can be deployed. We further show that if the CRs have apriori knowledge of the radio environment map (REM), then a much larger number of CRs can be deployed especially in a high density environment. Given REM information, we also look at the CR numbers achieved by two different types of techniques to process the scheduling information.Comment: to be presented at IEEE ICC 2009. This posting is the same as the original one. Only author's list is updated that was unfortunately not correctly mentioned in first versio

On the Impact of Antenna Topologies for Massive MIMO Systems

Approximate expressions for the spatial correlation of cylindrical and uniform rectangular arrays (URA) are derived using measured distributions of angles of departure (AOD) for both the azimuth and zenith domains. We examine massive multiple-input-multiple-output (MIMO) convergence properties of the correlated channels by considering a number of convergence metrics. The per-user matched filter (MF) signal-to-interference-plus-noise ratio (SINR) performance and convergence rate, to respective limiting values, of the two antenna topologies is also explored.Comment: 6 pages, 6 figure

On the Convergence of Massive MIMO Systems

In this paper we examine convergence properties of massive MIMO systems with the aim of determining the number of antennas required for massive MIMO gains. We consider three characteristics of a channel matrix and study their asymptotic behaviour. Furthermore, we derive ZF SNR and MF SINR for a scenario of unequal receive powers. In our results we include the effects of spatial correlation. We show that the rate of convergence of channel metrics is much slower than that of the ZF/MF precoder properties.Comment: 6 pages, 6 figures, ICC 201

Histopathological study of pancreatobiliary tumors in a tertiary care center: a 7 year study

Background: The aim of this study was to comprehensively analyse the histopathological spectrum of pancreatobiliary tumors with special reference to ampulla of Vater.Methods: The retrospective study was done for 5 years and a prospective study was carried out for 2 years in the Department of Pathology.Results: A total of 110 cases were included; 103 underwent a standard Whipple procedure and 7 underwent localised resection (partial pancreatectomy). The average age was 52.64 years (16-80 years) and males outnumbered females (3:2). Malignant (93.63%) lesions outweighed benign lesions (6.36%). Among malignant lesions, 71 (68.93%) were peri-ampullary, 15 (14.56%) were pancreatic, 11 (10.67%) were duodenal and only 6 (5.825%) were cholangiocarcinoma. The most common presenting feature was jaundice followed by pain in the abdomen. The mean tumor size was 2.38 cm (0.5-15cm). The pathological stage of most of the tumors was T2 (58.2%), followed by T3 (22.7%), T1 (11.8%) and T4 was only 1.8%. Proximal duodenal resection margin was free in 90.9%, distal duodenal resection margin was free in all cases, CBD resection margin was involved in only 2 cases (1.8%), while the pancreatic duct resection margin was involved in 2.7%. The nodal status was N0 in 61.8%, N1 in 23.6% and Nx in 9.1%.Conclusions: Adenocarcinoma (well differentiated-47.3%) is the most common histological variant of pancreatobiliary region

Non-Minimal Chaotic Inflation, Peccei-Quinn Phase Transition and non-Thermal Leptogenesis

We consider a phenomenological extension of the minimal supersymmetric standard model (MSSM) which incorporates non-minimal chaotic inflation, driven by a quadratic potential in conjunction with a linear term in the frame function. Inflation is followed by a Peccei-Quinn phase transition, based on renormalizable superpotential terms, which resolves the strong CP and mu problems of MSSM and provide masses lower than about 10^12 GeV for the right-handed (RH) (s)neutrinos. Baryogenesis occurs via non-thermal leptogenesis, realized by the out-of-equilibrium decay of the RH sneutrinos which are produced by the inflaton's decay. Confronting our scenario with the current observational data on the inflationary observables, the light neutrino masses, the baryon asymmetry of the universe and the gravitino limit on the reheat temperature, we constrain the strength of the gravitational coupling to rather large values (~45-2950) and the Dirac neutrino masses to values between about 1 and 10 GeV.Comment: Final versio