Search for long-lived, multi-charged particles in pp collisions at root s=7 TeV using the ATLAS detector

A search for highly ionising, penetrating particles with electric charges from vertical bar q vertical bar = 2e to 6e is performed using the ATLAS detector at the CERN Large Hadron Collider. Proton-proton collision data taken at root s = 7 TeV during the 2011 running period, corresponding to an integrated luminosity of 4.4 fb(-1), are analysed. No signal candidates are observed, and 95% confidence level cross-section upper limits are interpreted as mass-exclusion lower limits for a simplified Drell-Yan production model. In this model, masses are excluded from 50 GeV up to 430, 480, 490, 470 and 420 GeV for charges 2e, 3e, 4e, 5e and 6e, respectively. (c) 2013 CERN. Published by Elsevier B.V. All rights reserved

The Potential and Challenges of Nanopore Sequencing

A nanopore-based device provides single-molecule detection and analytical capabilities that are achieved by electrophoretically driving molecules in solution through a nano-scale pore. The nanopore provides a highly confined space within which single nucleic acid polymers can be analyzed at high throughput by one of a variety of means, and the perfect processivity that can be enforced in a narrow pore ensures that the native order of the nucleobases in a polynucleotide is reflected in the sequence of signals that is detected. Kilobase length polymers (single-stranded genomic DNA or RNA) or small molecules (e.g., nucleosides) can be identified and characterized without amplification or labeling, a unique analytical capability that makes inexpensive, rapid DNA sequencing a possibility. Further research and development to overcome current challenges to nanopore identification of each successive nucleotide in a DNA strand offers the prospect of ‘third generation’ instruments that will sequence a diploid mammalian genome for ~$1,000 in ~24 h.Molecular and Cellular BiologyPhysic

Collisional S-Matrix for the Vibrational Dynamics of H+H2 Including Dissociative Processes by Quantum Computing

Quantum circuit is developed and applied to compute accurately S matrix for the transitions between vibrational states of H2 in collisions with H at 100 eV laboratory collision energy. The effects of the discretized dissociative continuum to the transition cross sections are carefully studied and the maximum number of continua is found to provide convergence of the results within 5%. The results were confirmed by comparison with independent ODE solution of the time-dependent Schrodinger equation and comparison with few results form literature.Comment: 22 pages, 12 figrue

Rate Coefficient for H+ + H2(X1Σg+, ν = 0, J = 0) → H(1s) + H2+ Charge Transfer and Some Cosmological Implications

Krstić has carried out the first quantum mechanical calculations near threshold for the charge transfer (CT) process H+ + H2(X 1Σimg1.gif, ν = 0, J = 0) → H(1s) + H+2. These results are relevant for models of primordial galaxy and first star formation that require reliable atomic and molecular data for obtaining the hydrogen chemistry of the early universe. Using the results of Krstić, we calculate the relevant CT rate coefficient for temperatures between 100 and 30,000 K. We also present a simple fit that can be readily implemented into early universe chemical models. Additionally, we explore how the range of previously published data for this reaction translates into uncertainties in the predicted gas temperature and H2 relative abundance in a collapsing primordial gas cloud. Our new data significantly reduce these cosmological uncertainties that are due to the uncertainties in the previously published CT rate coefficients

Polarization curves in the ohmic controlled electrodeposition of metals

The conditions under which ohmic controlled metal electrodeposition occurs are discussed using a simple mathematical model. it is shown that ohmic controlled electrodeposition can be operative if the value of the exchange current density for the electrodeposition process is more than 10 times larger than the corresponding value of the limiting diffusion current density. In this case, a linear dependence of the current density on overpotential up to the value of the limiting diffusion current density can be observed. On the other hand, the initiation of dendrite growth under these circumstances is possible, even at very low values of overpotential, at the moment when the limiting diffusion current density is attained in potentiostatic electrodeposition. In this way, instead of a limiting diffusion current density plateau. an inflection point on the polarization curve can be observed, since dendritic growth is followed by an increase in the deposition current density. At the same time. it is shown that the ensemble of tips of dendrites can behave as an ensemble of microelectrodes working independently under mixed or activation control due to the absence of a common diffusion layer. This was confirmed by deposition of copper on a copper dendritic electrode and by silver electrodeposition from a silver nitrate solution onto a graphite substrate

High natural radiation exposure in radon spa areas: a detailed field investigation in Niska Banja (Balkan region)

The measurement campaigns have been done in the rural community of Niska. Banja, a spa town located in southern Serbia, to evaluate population exposure to natural radioactivity. After a screening survey in 200 houses, annual radon and thoron concentrations were measured in 34 houses, and in 2004 a detailed investigation was carried out at six houses with elevated indoor radon concentrations. The paper presents the results of these detailed measurements. The complementary techniques were applied to determine radon and thoron concentrations in indoor air, in soil gas, radon exhalation from soil, soil permeability, and indoor and outdoor gamma doses. Soil and water samples were collected and analysed in the laboratory. Indoor radon and thoron. concentrations were found to be more than 1 kBq m(-3) and 200 Bq m(-3) respectively. Extremely high concentrations of soil-gas radon ( GT 2000 kBq m(-3)) and radon exhalation rates (1.5 mBq m(-2) s(-1)) were observed. These results will be utilised to set up the methodology for a more systematic investigation. (c) 2006 Elsevier Ltd. All rights reserved