Vector Ambiguity and Freeness Problems in SL (2, ℤ).

We study the vector ambiguity problem and the vector freeness problem in SL(2,Z). Given a finitely generated n×n matrix semigroup S and an n-dimensional vector x, the vector ambiguity problem is to decide whether for every target vector y=Mx, where M∈S, M is unique. We also consider the vector freeness problem which is to show that every matrix M which is transforming x to Mx has a unique factorization with respect to the generator of S. We show that both problems are NP-complete in SL(2,Z), which is the set of 2×2 integer matrices with determinant 1. Moreover, we generalize the vector ambiguity problem and extend to the finite and k-vector ambiguity problems where we consider the degree of vector ambiguity of matrix semigroups

Studying Diquark Structure of Heavy Baryons in Relativistic Heavy Ion Collisions

We propose the enhancement of $\Lambda_c$ yield in heavy ion collisions at RHIC and LHC as a novel signal for the existence of diquarks in the strongly coupled quark-gluon plasma produced in these collisions as well as in the $\Lambda_c$. Assuming that stable bound diquarks can exist in the quark-gluon plasma, we argue that the yield of $\Lambda_c$ would be increased by two-body collisions between $ud$ diquarks and $c$ quarks, in addition to normal three-body collisions among $u$, $d$ and $c$ quarks. A quantitative study of this effect based on the coalescence model shows that including the contribution of diquarks to $\Lambda_c$ production indeed leads to a substantial enhancement of the $\Lambda_c/D$ ratio in heavy ion collisions.Comment: Prepared for Chiral Symmetry in Hadron and Nuclear Physics (Chiral07), Nov. 13-16, 2007, Osaka, Japa

Signatures for doubly-charged Higgsinos at colliders

Several supersymmetric models with extended gauge structures predict light doubly-charged Higgsinos. Their distinctive signature at the large hadron collider is highlighted by studying their production and decay characteristics.Comment: 3 pages, 4 figures, Latex. Submitted for SUSY 2008 proceeding

Permutation symmetry for the tomographic probability distribution of a system of identical particles

The symmetry properties under permutation of tomograms representing the states of a system of identical particles are studied. Starting from the action of the permutation group on the density matrix we define its action on the tomographic probability distribution. Explicit calculations are performed in the case of the two-dimensional harmonic oscillator.Comment: 13 pages, latex, no figure

Differences in the Prevalence of Non-Communicable Disease between Slum Dwellers and the General Population in a Large Urban Area in Brazil.

Residents of urban slums are at greater risk for disease than their non-slum dwelling urban counterparts. We sought to contrast the prevalences of selected non-communicable diseases (NCDs) between Brazilian adults living in a slum and the general population of the same city, by comparing the age and sex-standardized prevalences of selected NCDs from a 2010 survey in Pau da Lima, Salvador Brazil, with a 2010 national population-based telephone survey. NCD prevalences in both populations were similar for hypertension (23.6% (95% CI 20.9⁻26.4) and 22.9% (21.2⁻24.6), respectively) and for dyslipidemia (22.7% (19.8⁻25.5) and 21.5% (19.7⁻23.4)). Slum residents had higher prevalences of diabetes mellitus (10.1% (7.9⁻12.3)) and of overweight/obesity (46.5% (43.1⁻49.9)), compared to 5.2% (4.2⁻6.1) and 40.6% (38.5⁻42.8) of the general population in Salvador. Fourteen percent (14.5% (12.1⁻17.0)) of slum residents smoked cigarettes compared to 8.3% (7.1⁻9.5) of the general population in Salvador. The national telephone survey underestimated the prevalence of diabetes mellitus, overweight/obesity, and smoking in the slum population, likely in part due to differential sampling inside and outside of slums. Further research and targeted policies are needed to mitigate these inequalities, which could have significant economic and social impacts on slum residents and their communities

The atmospheric effects of stratospheric aircraft: A current consensus

In the early 1970's, a fleet of supersonic aircraft flying in the lower stratosphere was proposed. A large fleet was never built for economic, political, and environmental reasons. Technological improvements may make it economically feasible to develop supersonic aircraft for current markets. Some key results of earlier scientific programs designed to assess the impact of aircraft emissions on stratospheric ozone are reviewed, and factors that must be considered to assess the environmental impact of aircraft exhaust are discussed. These include the amount of nitrogen oxides injected in the stratosphere, horizontal transport, and stratosphere/troposphere assessment models are presented. Areas in which improvements in scientific understanding and model representation must be made to reduce the uncertainty in model calculations are identified

New Approach for Measuring ∣Vub∣|V_{ub}| at Future BB-Factories

It is suggested that the measurements of hadronic invariant mass ($m_X$) distributons in the inclusive $B \rightarrow X_{c(u)} l \nu$ decays can be useful in extracting the CKM matrix element $|V_{ub}|$. We investigated hadronic invariant mass distributions within the various theoretical models of HQET, FAC and chiral lagrangian as well as ACCMM model. It is also emphasized that the $m_X$ distribution even at the region $m_{X} > m_{D}$ in the inclusive $b\rightarrow u$ are effetive in selecting the events, experimentally viable at the future asymmetric $B$ factories, with better theoretical understandings.Comment: 11 pages not including 1 figur