Relativistic atomic level calculations with nuclei carrying additional fractional charges

One-electron energy levels and wavelengths have been calculated for Na-like ions whose nuclei carry quarks with additional charges ±e/3, ±2e/3. The calculations are based on relativistic self-consistent field procedures. The deviations from experimental values exhibit regularities which allow an extrapolation for the wavelengths of 3s - 3p, 3s - 4p, 3p - 3d, and 3p - 4s transitions for the nuclear charge Z = 11± 1/3, ±2/3. A number of transitions are found in the region of visible light which could be used in an optical search for quark atoms.

Arc Length

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Arc Length pdf

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A comparison between maximum length sequence and conventional auditory brainstem responses as a screening tool for auditory sensitivity

This paper compares conventional auditory brainstem response tests (ABRs) and Maximum Length Sequence auditory brainstem response tests (MLS ABRs). The results found that the faster MLS ABRs could prove an accurate screening tool for auditory sensitivity.

The influence of sentence length and complexity on the speechreading performance of profoundly deaf children

This paper reviews speechreading and the effect of sentence length and linguistic complexity on deaf children.

Effect of acyl chain length on transfection efficiency and toxicity of polyethylenimine

Polyethylenimine (PEI) is an efficient nonviral gene delivery vector because of its high buffering capacity and DNA condensation ability. In our study, the amino groups on the polymeric backbone were acylated using acetic or propionic anhydride to alter the protonation behaviour and the hydrophilic/hydrophobic balance of the polymer. The concentration of acylated primary amines was determined using trinitrobenzene sulphonic acid assay. Results showed that our modified polymers had lower buffering capacities in solutions compared to PEI. The polymers were complexed with plasmid encoding enhanced green fluorescent protein at three different ratios (1:1, 1:2 and 1:10 w/w DNA to polymer) to form polyplexes and their toxicities and transfection efficiencies were evaluated in HEK 293 cells. Acylation reduced the number of primary amines on the polymer and the surface charge, improving haemocompatibility and reducing cytotoxicity. The reduction in the concentration of amino groups helped to optimise DNA compaction and facilitated polyplex dissociation in the cell, which increased transfection efficiency of the modified polymers compared to the parent polymer. Polymers with buffering capacities greater than 50% and less than 80% relative to PEI, showed higher transfection efficiencies than PEI. The propionic anhydride modified polymers had appropriate interactions with DNA which provided both DNA compaction and polyplex dissociation. These systems interacted better with the cell membrane because of their slightly higher lipophilicity and formed polyplexes which were less cytotoxic than polyplexes of acetic anhydride modified polymers. Among the vectors tested, 1:0.3 mol/mol PEI:propionic anhydride in a 1:2 w/w DNA:polymer composition provided the best transfection system with improved transfection efficiency and reduced cytotoxicity.

The influence of winter oilseed rape (Brassica napus ssp oleifera var. biennis) canopy size on grass weed growth and grass weed seed return

Four experiments conducted over three seasons (2002-05) at the Crops Research Unit, University of Reading, investigated effects of canopy management of autumn sown oilseed rape (Brassica napus L. ssp. oleifera var. biennis (DC.) Metzg.) on competition with grass weeds. Emphasis was placed on the effect of the crop on the weeds. Rape canopy size was manipulated using sowing date, seed rate and the application of autumn fertilizer. Lolium multiflorum Lam., L. x boucheanum Kunth and Alopecurus myosuroides Huds. were sown as indicative grass weeds. The effects of sowing date, seed rate and autumn nitrogen on crop competitive ability were correlated with rape biomass and fractional interception of photosynthetically active radiation (PAR) by the rape floral layer, to the extent that by spring there was good evidence of crop: weed replacement. An increase in seed rate up to the highest plant densities tested increased both rape biomass and competitiveness, e.g. in 2002/3, L. multiflorum head density was reduced from 539 to 245 heads/m(2) and spikelet density from 13 170 to 5960 spikelets/m(2) when rape plant density was increased from 16 to 81 plants/m(2). Spikelets/head of Lolium spp. was little affected by rape seed rate, but the length of heads of A. myosuroides was reduced by 9 % when plant density was increased from 29-51 plants/m(2). Autumn nitrogen increased rape biomass and reduced L. multiflorum head density (415 and 336 heads/m(2) without and with autumn nitrogen, respectively) and spikelet density (9990 and 8220 spikelets/m(2) without and with autumn nitrogen, respectively). The number of spikelets/head was not significantly affected by autumn nitrogen. Early sowing could increase biomass and competitiveness, but poor crop establishment sometimes overrode the effect. Where crop and weed establishment was similar for both sowing dates, a 2-week delay (i.e. early September to mid-September) increased L. multiflorum head density from 226 to 633 heads/m(2) and spikelet density from 5780 to 15 060 spikelets/m(2).

The relationships of age and length of service with job satisfaction: an examination of hotel employees in Thailand

Earlier studies suggest age is positively associated with job satisfaction, while others use length of service, or tenure, as a predictor of job satisfaction levels. This article examines whether age and tenure are individual determinants of satisfaction, or whether there is an interaction between the two. The results indicate that employee age is not significantly associated with overall job satisfaction level, but that tenure is. There is also significant relationship between tenure and facets of satisfaction (job, pay and fringe benefits), but the effect of tenure on satisfaction is significantly modified by age.

Minimum aberration construction results for nonregular two-level fractional factorial designs

Nonregular two-level fractional factorial designs are designs which cannot be specified in terms of a set of defining contrasts. The aliasing properties of nonregular designs can be compared by using a generalisation of the minimum aberration criterion called minimum G2-aberration.Until now, the only nontrivial designs that are known to have minimum G2-aberration are designs for n runs and m n–5 factors. In this paper, a number of construction results are presented which allow minimum G2-aberration designs to be found for many of the cases with n = 16, 24, 32, 48, 64 and 96 runs and m n/2–2 factors.