Tight-binding parameters for charge transfer along DNA

We systematically examine all the tight-binding parameters pertinent to charge transfer along DNA. The $\pi$ molecular structure of the four DNA bases (adenine, thymine, cytosine, and guanine) is investigated by using the linear combination of atomic orbitals method with a recently introduced parametrization. The HOMO and LUMO wavefunctions and energies of DNA bases are discussed and then used for calculating the corresponding wavefunctions of the two B-DNA base-pairs (adenine-thymine and guanine-cytosine). The obtained HOMO and LUMO energies of the bases are in good agreement with available experimental values. Our results are then used for estimating the complete set of charge transfer parameters between neighboring bases and also between successive base-pairs, considering all possible combinations between them, for both electrons and holes. The calculated microscopic quantities can be used in mesoscopic theoretical models of electron or hole transfer along the DNA double helix, as they provide the necessary parameters for a tight-binding phenomenological description based on the $\pi$ molecular overlap. We find that usually the hopping parameters for holes are higher in magnitude compared to the ones for electrons, which probably indicates that hole transport along DNA is more favorable than electron transport. Our findings are also compared with existing calculations from first principles.Comment: 15 pages, 3 figures, 7 table

Observation of Orbitally Excited B_s Mesons

We report the first observation of two narrow resonances consistent with states of orbitally excited (L=1) B_s mesons using 1 fb^{-1} of ppbar collisions at sqrt{s} = 1.96 TeV collected with the CDF II detector at the Fermilab Tevatron. We use two-body decays into K^- and B^+ mesons reconstructed as B^+ \to J/\psi K^+, J/\psi \to \mu^+ \mu^- or B^+ \to \bar{D}^0 \pi^+, \bar{D}^0 \to K^+ \pi^-. We deduce the masses of the two states to be m(B_{s1}) = 5829.4 +- 0.7 MeV/c^2 and m(B_{s2}^*) = 5839.7 +- 0.7 MeV/c^2.Comment: Version accepted and published by Phys. Rev. Let

Towards a greater dialogue on disability between Muslims and Christians

Attitudes to disability and disabled people by Muslims – focusing on attitudes in the Middle East and North Africa - and Christians – focusing on the West (here taken to mean Europe, North America and Australasia) - were examined through a grounded theory literature search, with the study being divided into three phases of reading and analysis. The aims of study were to develop a dialogue on disability between the two cultures, to inform an understanding of the attitudes to disability in the two cultures, and to inform cultural practice in promoting support and equality in both cultures. The study finds that Islam and Christianity have much in common and are a force for good in promoting and developing disability equality in both Muslim and Christian cultures

Measurement of the ttbar Production Cross Section in ppbar collisions at sqrt s = 1.96 TeV in the All Hadronic Decay Mode

We report a measurement of the ttbar production cross section using the CDF-II detector at the Fermilab Tevatron. The analysis is performed using 311 pb-1 of ppbar collisions at sqrt(s)=1.96 TeV. The data consist of events selected with six or more hadronic jets with additional kinematic requirements. At least one of these jets must be identified as a b-quark jet by the reconstruction of a secondary vertex. The cross section is measured to be sigma(tbart)=7.5+-2.1(stat.)+3.3-2.2(syst.)+0.5-0.4(lumi.) pb, which is consistent with the standard model prediction.Comment: By CDF collaboratio

Search for chargino-neutralino production in ppbar collisions at sqrt(s) = 1.96 TeV

We present the results of a search for associated production of the chargino and neutralino supersymmetric particles using up to 1.1 fb-1 of integrated luminosity collected by the CDF II experiment at the Tevatron ppbar collider at a center-of-mass energy of 1.96 TeV. The search is conducted by analyzing events with a large transverse momentum imbalance and either three charged leptons or two charged leptons of the same electric charge. The numbers of observed events are found to be consistent with standard model expectations. Upper limits on the production cross section are derived in different theoretical models. In one of these models a lower limit on the mass of the chargino is set at 129 GeV/c^2 at the 95% confidence level.Comment: To be submitted to Phys.Rev.Let

Preliminary remedial action objectives for the Tank 16 groundwater operable unit

Tank 16 is a High Level Radioactive Waste tank in the H-Area Tank Farm on the Savannah River Site that was placed into service in May 1959. A leak was detected in one of the construction weld joints while the tank was being filled. Before jet evacuation of the tank waste was completed, the leak overflowed the annulus pan and an estimated 16 to 700 gallons of waste escaped to the environment (soil and groundwater) over a six hour period contaminating approximately 1,600--70,000 cubic feet of soil with up to 5000 curies of activity (principally Cs[sup 137]). The Tank 16 bottom is constructed below the groundwater table which resulted in almost immediate contamination of that medium. Low groundwater flow rates, the ion exchange property of adjacent soils, and the distance to the nearest surface water bodies (1,500 to 8,000 feet) indicates that surface water and sediment outcrop of contaminates may be expected between 44 and 530 years (Poe et al., 1974). Remedial action objectives consist of medium-specific and operable unit specific goals for protecting human health and the environment. These objectives are specific and do not limit the range of alternatives that may be developed.A range of remedial technologies, which provides for treatment, containment, and removal requirements of contaminated media remaining at the Tank 16 groundwater operable unit, is identified and developed for each general response action

F/H Effluent Treatment Facility filtration upgrade alternative evaluations overview

The F/H Effluent Treatment Facility (ETF) at the Savannah River Site (SRS) was designed to treat process wastewater from the 200-F/H Production Facilities (routine wastewater) as well as intermittent flows from the F/H Retention Basins and F/H Cooling Water Basins (nonroutine wastewater). Since start-up of the ETF at SRS in 1988, the treatment process has experienced difficulties processing routine and nonroutine wastewater. Studies have identified high bacteria and bacterial decomposition products in the wastewater as the cause for excessive fouling of the filtration system. In order to meet Waste Management requirements for the treatment of processed wastewater, an upgrade of the ETF filtration system is being developed. This upgrade must be able to process the nonroutine wastewater at design capacity. As a result, a study of alternative filter technologies was conducted utilizing simulated wastewater. The simulated wastewater tests have been completed. Three filter technologies, centrifugal polymeric ultrafilters, tubular polymeric ultrafilters, and backwashable cartridge filters have been selected for further evaluation utilizing actual ETF wastewater