DOE SNF technology development necessary for final disposal

Existing technology is inadequate to allow safe disposal of the entire inventory of US Department of Energy (DOE) spent nuclear fuel (SNF). Needs for SNF technology development were identified for each individual fuel type in the diverse inventory of SNF generated by past, current, and future DOE materials production, as well as SNF returned from domestic and foreign research reactors. This inventory consists of 259 fuel types with different matrices, cladding materials, meat composition, actinide content, and burnup. Management options for disposal of SNF include direct repository disposal, possible including some physical or chemical preparation, or processing to produce a qualified waste form by using existing aqueous processes or new treatment processes. Technology development needed for direct disposal includes drying, mitigating radionuclide release, canning, stabilization, and characterization technologies. While existing aqueous processing technology is fairly mature, technology development may be needed to apply one of these processes to SNF different than for which the process was originally developed. New processes to treat SNF not suitable for disposal in its current form were identified. These processes have several advantages over existing aqueous processes

WIMP Annual Modulation with Opposite Phase in Late-Infall Halo Models

We show that in the late-infall model of our galactic halo by P. Sikivie the expected phase of the annual modulation of a WIMP halo signal in direct detection experiments is opposite to the one usually expected. If a non-virialized halo component due to the infall of (collisionless) dark matter particles cannot be rejected, an annual modulation in a dark matter signal should be looked for by experimenters without fixing the phase a-priori. Moreover, WIMP streams coming to Earth from directions above and below the galactic plane should be expected, with a characteristic pattern of arrival directions.Comment: 15 pages, 5 figure

Language and learning science in South Africa

South Africa is a multilingual country with 11 official languages. However, English dominates as the language of access and power and although the Language-in- Education Policy (1997) recommends school language policies that will promote additive bilingualism and the use of learners' home languages as languages of learning and teaching, there has been little implementation of these recommendations by schools. This is despite the fact that the majority of learners do not have the necessary English language proficiency to successfully engage with the curriculum and that teachers frequently are obliged to resort to using the learners' home language to mediate understanding. This research investigates the classroom language practices of six Grade 8 science teachers, teaching science through the medium of English where they and their learners share a common home language, Xhosa. Teachers' lessons were videotaped, transcribed and analysed for the opportunities they offered learners for language development and conceptual challenge. The purpose of the research is to better understand the teachers' perceptions and problems and to be able to draw on examples of good practice, to inform teacher training and to develop a coherent bilingual approach for teaching science through the medium of English as an additional language

Animacy effects on the processing of intransitive verbs:An eye-tracking study

<p>This paper tested an assumption of the gradient model of split intransitivity put forward by Sorace (“Split Intransitivity Hierarchy” (SIH), 2000, 2004), namely that agentivity is a fundamental feature for unergatives but not for unaccusatives. According to this hypothesis, the animacy of the verb’s argument should affect the processing of unergative verbs to a greater extent than unaccusative verbs. By using eye-tracking methodology we monitored the online processing and integration costs of the animacy of the verb’s argument in intransitive verbs. We observed that inanimate subjects caused longer reading times only for unergative verbs, whereas the animacy of the verb’s argument did not influence the pattern of results for unaccusatives. In addition, the unergative verb data directly support the existence of gradient effects on the processing of the subject argument.</p

Dynamic Evolution Model of Isothermal Voids and Shocks

We explore self-similar hydrodynamic evolution of central voids embedded in an isothermal gas of spherical symmetry under the self-gravity. More specifically, we study voids expanding at constant radial speeds in an isothermal gas and construct all types of possible void solutions without or with shocks in surrounding envelopes. We examine properties of void boundaries and outer envelopes. Voids without shocks are all bounded by overdense shells and either inflows or outflows in the outer envelope may occur. These solutions, referred to as type $\mathcal{X}$ void solutions, are further divided into subtypes $\mathcal{X}_{\rm I}$ and $\mathcal{X}_{\rm II}$ according to their characteristic behaviours across the sonic critical line (SCL). Void solutions with shocks in envelopes are referred to as type $\mathcal{Z}$ voids and can have both dense and quasi-smooth edges. Asymptotically, outflows, breezes, inflows, accretions and static outer envelopes may all surround such type $\mathcal{Z}$ voids. Both cases of constant and varying temperatures across isothermal shock fronts are analyzed; they are referred to as types $\mathcal{Z}_{\rm I}$ and $\mathcal{Z}_{\rm II}$ void shock solutions. We apply the `phase net matching procedure' to construct various self-similar void solutions. We also present analysis on void generation mechanisms and describe several astrophysical applications. By including self-gravity, gas pressure and shocks, our isothermal self-similar void (ISSV) model is adaptable to various astrophysical systems such as planetary nebulae, hot bubbles and superbubbles in the interstellar medium as well as supernova remnants.Comment: 24 pages, 13 figuers, accepted by ApS

An AeroCom initial assessment – optical properties in aerosol component modules of global models

The AeroCom exercise diagnoses multi-component aerosol modules in global modeling. In an initial assessment simulated global distributions for mass and mid-visible aerosol optical thickness (aot) were compared among 20 different modules. Model diversity was also explored in the context of previous comparisons. For the component combined aot general agreement has improved for the annual global mean. At 0.11 to 0.14, simulated aot values are at the lower end of global averages suggested by remote sensing from ground (AERONET ca. 0.135) and space (satellite composite ca. 0.15). More detailed comparisons, however, reveal that larger differences in regional distribution and significant differences in compositional mixture remain. Of particular concern are large model diversities for contributions by dust and carbonaceous aerosol, because they lead to significant uncertainty in aerosol absorption (aab). Since aot and aab, both, influence the aerosol impact on the radiative energy-balance, the aerosol (direct) forcing uncertainty in modeling is larger than differences in aot might suggest. New diagnostic approaches are proposed to trace model differences in terms of aerosol processing and transport: These include the prescription of common input (e.g. amount, size and injection of aerosol component emissions) and the use of observational capabilities from ground (e.g. measurements networks) or space (e.g. correlations between aerosol and clouds)

Dynamic Evolution of a Quasi-Spherical General Polytropic Magnetofluid with Self-Gravity

In various astrophysical contexts, we analyze self-similar behaviours of magnetohydrodynamic (MHD) evolution of a quasi-spherical polytropic magnetized gas under self-gravity with the specific entropy conserved along streamlines. In particular, this MHD model analysis frees the scaling parameter $n$ in the conventional polytropic self-similar transformation from the constraint of $n+\gamma=2$ with $\gamma$ being the polytropic index and therefore substantially generalizes earlier analysis results on polytropic gas dynamics that has a constant specific entropy everywhere in space at all time. On the basis of the self-similar nonlinear MHD ordinary differential equations, we examine behaviours of the magnetosonic critical curves, the MHD shock conditions, and various asymptotic solutions. We then construct global semi-complete self-similar MHD solutions using a combination of analytical and numerical means and indicate plausible astrophysical applications of these magnetized flow solutions with or without MHD shocks.Comment: 21 pages, 7 figures, accepted for publication in APS

Accumulation of Succinyl Coenzyme A Perturbs the Methicillin-Resistant Staphylococcus aureus (MRSA) Succinylome and Is Associated with Increased Susceptibility to Beta-Lactam Antibiotics

Penicillin binding protein 2a (PBP2a)-dependent resistance to β-lactam antibiotics in methicillin-resistant Staphylococcus aureus (MRSA) is regulated by the activity of the tricarboxylic acid (TCA) cycle via a poorly understood mechanism. We report that mutations in sucC and sucD, but not other TCA cycle enzymes, negatively impact β-lactam resistance without changing PBP2a expression. Increased intracellular levels of succinyl coenzyme A (succinyl-CoA) in the sucC mutant significantly perturbed lysine succinylation in the MRSA proteome. Suppressor mutations in sucA or sucB, responsible for succinyl-CoA biosynthesis, reversed sucC mutant phenotypes. The major autolysin (Atl) was the most succinylated protein in the proteome, and increased Atl succinylation in the sucC mutant was associated with loss of autolytic activity. Although PBP2a and PBP2 were also among the most succinylated proteins in the MRSA proteome, peptidoglycan architecture and cross-linking were unchanged in the sucC mutant. These data reveal that perturbation of the MRSA succinylome impacts two interconnected cell wall phenotypes, leading to repression of autolytic activity and increased susceptibility to β-lactam antibiotics. IMPORTANCE mecA-dependent methicillin resistance in MRSA is subject to regulation by numerous accessory factors involved in cell wall biosynthesis, nucleotide signaling, and central metabolism. Here, we report that mutations in the TCA cycle gene, sucC, increased susceptibility to β-lactam antibiotics and was accompanied by significant accumulation of succinyl-CoA, which in turn perturbed lysine succinylation in the proteome. Although cell wall structure and cross-linking were unchanged, significantly increased succinylation of the major autolysin Atl, which was the most succinylated protein in the proteome, was accompanied by near complete repression of autolytic activity. These findings link central metabolism and levels of succinyl-CoA to the regulation of β-lactam antibiotic resistance in MRSA through succinylome-mediated control of two interlinked cell wall phenotypes. Drug-mediated interference of the SucCD-controlled succinylome may help overcome β-lactam resistance

Gambling: Electronic friends or a threat to one's health and personal development?

Gambling has become quite common in Sweden. The Swedish National Institute of Public Health (2010) has reported that about 70% of the Swedish population has gambled at least once during the last 12 months. Half of the population had gambled with money by 18 years of age and about 11% had gambled for the first time when they were 12-years-old or younger. In the report from the Swedish National Institute of Public Health, gambling problems are related to health problems and risky alcohol consumption. The highest problem rate is found among men aged 18 to 24; almost 1 in 10 had some gambling problems. The share of problem gamblers is found to be twice as high among the under-age gamblers as it is among the population as a whole. Young people gamble less but develop gambling problems to a larger extent than adult gamblers. In this article young people's gambling and their gambling careers are analysed as a natural part of their internalisation of other adult habits

Perspectivization and modes of quoting in Hungarian

This paper examines modes of quoting with special regard to the organization of perspective. Due to the pragmatic interest of the study, our focus is on the functioning of two context-dependent vantage points, the subject of consciousness and the referential centre. Our key question about the former is to whom speaking as a sign of active consciousness is attributed and how this is linguistically marked. As regards the latter, the central issue is from where and how the spatio-temporal and interpersonal relations of the quoted discourse are represented.Further problems to be discussed include the questions of how and to what extent quoting is associated with pragmatic or metapragmatic awareness, and how various quoting modes may differ along this dimension.Although the paper is mostly concerned with a ‘universal pragmatic’ characterization of the functioning of perspective in quotations, it also highlights some language-particular features of Hungarian quoting strategies and touches on their evolution in the history of the language