Development and Demonstration of a Method to Evaluate Bio-Sampling Strategies Using Building Simulation and Sample Planning Software

In an effort to validate and demonstrate response and recovery sampling approaches and technologies, the U.S. Department of Homeland Security (DHS), along with several other agencies, have simulated a biothreat agent release within a facility at Idaho National Laboratory (INL) on two separate occasions in the fall of 2007 and the fall of 2008. Because these events constitute only two realizations of many possible scenarios, increased understanding of sampling strategies can be obtained by virtually examining a wide variety of release and dispersion scenarios using computer simulations. This research effort demonstrates the use of two software tools, CONTAM, developed by the National Institute of Standards and Technology (NIST), and Visual Sample Plan (VSP), developed by Pacific Northwest National Laboratory (PNNL). The CONTAM modeling software was used to virtually contaminate a model of the INL test building under various release and dissemination scenarios as well as a range of building design and operation parameters. The results of these CONTAM simulations were then used to investigate the relevance and performance of various sampling strategies using VSP. One of the fundamental outcomes of this project was the demonstration of how CONTAM and VSP can be used together to effectively develop sampling plans to support the various stages of response to an airborne chemical, biological, radiological, or nuclear event. Following such an event (or prior to an event), incident details and the conceptual site model could be used to create an ensemble of CONTAM simulations which model contaminant dispersion within a building. These predictions could then be used to identify priority area zones within the building and then sampling designs and strategies could be developed based on those zones.     

Turn-taking patterns in human discourse and their impact on group communication service design

Recent studies demonstrated the benefit of integrating speaker prediction features into the design of group-communication services supporting multiparty online discourse. This paper aims at delivering a more elaborate analysis of speaker prediction by analyzing a larger volume of data. Moreover, it tests the existence of speakers dominating speaking time. Towards this end, we analyze tens of hours of recorded meeting and lecture sessions. Our principal results for meeting-like interaction manifest that the next speaker is one of the last four speakers with over 90% probability. This is seen consistently across our data with little variance (standard deviation of 8.71%) independent of the total number of potential speakers. Furthermore, lecture time is in most cases significantly dominated by the tutor. In meetings, although a single dominating speaker is always evident, domination exhibited high variability. Generally, our findings strengthen and further motivate the act of incorporating user-beha vior awareness into group communication service design.     

On the effect of TiO2 additions on sintering of UO2

Small additions of TiO₂ are known to increase the density of sintered UO₂. It is shown that this effect coincides with an increase in the diffusion rate of the slower moving ion, the uranium ion. Quantitative metallography and measurement of the gas release following high-dose ion-bombardment show that small amounts of titanium are soluble in UO₂. Possible mechanisms by which TiO₂ affects the disorder of UO₂ are discussed. Reduction of TiO₂ and interstitial solution of the small titanium ions are favoured. Similar experiments are reported for ThO₂+TiO₂.     

Studies of the internal flow process in polymers by 1H NMR microscopy at 500 MHz

Intrinsic subthreshold oscillations in the membrane potential are a common property of many neurons in the peripheral and central nervous system. When such oscillations are combined with noise, interesting signal encoding and neuromodulatory properties are obtained which allow, for example, sensitivity adjustment or differential encoding of stimuli. Here we demonstrate that a noisy Hodgkin/Huxley-model for subthreshold oscillations, when tuned to maximum sensitivity, can be significantly modulated by even minor physiological changes in the oscillation parameters amplitude or frequency. Given the ubiquity of subthreshold oscillating neurons, it can be assumed that these findings reflect principle encoding properties which are relevant for an understanding of sensitivity and neuromodulation in peripheral and central neurons.     

The behaviour of single atoms of molybdenum in urania

Computer simulation techniques are used to investigate the behaviour of single atoms of Mo in UO_2±x. In UO_2−x, Mo is calculated to be present as neutral atoms in bound Schottky trio sites. In UO_2+x, most of the Mo is calculated to be in isolated uranium vacancy sites with Mo ionisation increasing with the O/U ratio. The behaviour near stoichiometric composition is more complex and is found to be very sensitive to changes in O/U ratio. An approximation to the free energy change associated with Mo incorporation in urania is plotted as a function of O/U ratio and Mo concentration. Although this plot is found to be in agreement with the observed insoluble character of Mo in urania, at high O/U ratios and very low Mo concentrations, Mo in solution may be preferred over Mo in the gaseous state.     

Nocturnal enuresis in children]

After allergic disorders, nocturnal enuresis is the most common chronic childhood condition. Recent research has yielded abundant new knowledge about the condition, especially about its aetiology and pathophysiology, and the psychological consequences. A hereditary background has been substantiated by the identification in genetic linkage studies of areas in chromosomes 12 and 13 that are manifestly associated with bedwetting, though genotype expression in the phenotype appears to be complex and heterogeneous. Pathophysiologically, findings in current intensive research suggest three interactive factors to be involved: (i) relative nocturnal polyuria, due to insufficient antidiuretic hormone release during sleep in pre-teenagers, and due to renal tubular dysfunction in adolescents and adults; (ii) reduced nocturnal bladder capacity, especially in the 33 per cent of cases which do not respond to desmopressin treatment; and (iii) the patient's inability to waken in response to signals from a full bladder. Recent findings have also confirmed previous reports that with very few exceptions bedwetting is not caused by psychological factors. On the contrary, the condition causes psychological problems manifested in reduced self-esteem, shame and guilt, though self-esteem is restored by successful treatment. Active treatment should be started as soon as the child is ready to receive it, the main options being an enuresis alarm, desmopressin, or a combination of the two. If reduced bladder capacity is suspected, treatment with a detrusor relaxant should be included.     

Grain-Boundary Diffusion of U in Pure and Doped Uranium Carbides with Different C/U Ratios

"The grain-boundary diffusivity of U in UC was measured between 1200" and 2200°C in pure carbides with a wide range of C/U ratios (0.93 to 2.00) and in material doped with up to 2.4 wt% W, V, or Ta. Grain-boundary diffusion is ∼ 10³ to 10⁵ times faster than volume diffusion, and, for UC_1,0, has an activation enthalpy of 75.9 ± 9.1 kcal/mol, ∼ 55% of that for volume diffusion. In the monocarbide region, grain-boundary mobility increases as the C/U ratio decreases and is impeded by the addition of impurities.     

Fabrication of short channel MOSFETs with refractory metal gates using RF sputter etching

Fabrication of sub-μm p-channel MOSFETs with refractory metal gates using novel refinements of conventional photolithographic procedures is described. The method avoids the need for direct electron beam writing on the wafer and for ion implantation instead of diffusion. Autoregistration Mo gate structures down to 2 μm corresponding to an estimated channel length of 0 · 7 μm were made using RF sputter etching for the drain-source windows while masking with a positive photoresist. This was contact patterned using a chromium-on-glass mask made by electron beam writing and RF sputter etching. Sputter-deposited boron-doped SiO₂ was used as the diffusion source for the source-drain areas.The transistors were made on (100) phosphorus doped n-type silicon with an impurity concentration of 2 . 10¹⁶ cm^?3. Fabricated devices with channel lengths ≥ 1 · 7 μm had an apparent threshold voltage of 2·5 V (10 μA criterion) and for 1·7 μm channel length an apparent punch-through voltage of 18 V. A sputtered Mo layer ? 1 μm thick was used as gate material.A distinct advantage of using sputter etching with a single system capable of both deposition and etching is that it is possible to go directly to the next steps without exposure to air. These steps are mask removal in a partial H₂ and O₂ plasma, followed by further Argon sputter-etching and sputter deposition of a doped oxide diffusion source on the sputter-etched cleaned surface. This promises a better reproducibility of surface doping as there should be less oxide and less contamination than in conventional processes. The characteristics of the fabricated transistors did not indicate any un-annealable drift or gate oxide damage due to the presence of the plasma provided the Mo layer was sufficiently thick. Thus sputter etching which offers good resolution can be used in MOS fabrication.Due to its lower resistivity, Mo, which can be used an an additional interconnection layer (isolated from the A1 layer) offers better speed potential than Si, in certain types of circuits, e.g. high speed memories with long address lines.With a proper background doping of the wafer and diffusion time and temperature it was possible to obtain $\text{? 0 · 6 μm}$ lateral diffusion below the gate from both source and drain regions. It was thus possible to obtain sub-μm p-channel MOSFETs even while working close to the limits of normal optical contact production of micropatterns, which is 1–2 μm.     

Contamination of cooked peeled shrimp (Pandalus borealis) by Listeria monocytogenes during processing at two processing plants

Listeria spp. and Listeria monocytogenes contamination was evaluated in cooked peeled shrimp (final or semifinal product, 82 samples) and the shrimp-processing environment (two plants, 613 samples) in eight surveys conducted from 1998 through 2001. Listeria was detected in 12.5% (78) of the 695 samples (11.2% of the samples were positive for L. monocytogenes), but none of the samples of final product contained Listeria. One hundred seventy-two L. monocytogenes isolates were characterized by pulsed-field gel electrophoresis. Cleavage with macrorestriction enzymes AscI and ApaI yielded 14 different pulsotypes in the plants; two types were dominant, one in each plant. Sixty-three of the 106 isolates in plant A and 43 of the 66 isolates in plant B were of the dominant types. Certain strains, mainly of serotypes 1/2c and 4b and pulsotypes 1A and 2H, were persistent for long periods in both plants. Adaptation of good hygienic practices in the processing plants, including strict rules concerning traffic of staff and equipment, and existing hygienic requirements appeared to be effective in preventing contamination between areas within plants and in the final product. The persistence of Listeria strains in these two processing plants indicates the importance of detecting the places in the processing environment (e.g., transporters, equipment, floors, and drains) where L. monocytogenes can survive so that cleaning and disinfection efforts can be directed to such niches.