Analysis of computational problems expressing the overall uncertainties: photons, neutrons and electrons

In the frame of the EU Coordination Action CONRAD (coordinated network for radiation dosimetry), WP4 was dedicated to work on computational dosimetry with an action entitled 'Uncertainty assessment in computational dosimetry: an intercomparison of approaches'. Participants attempted one or more of eight problems. This paper presents the results from problems 4-8-dealing with the overall uncertainty budget estimate; a short overview of each problem is presented together with a discussion of the most significant results and conclusions. The scope of the problems discussed here are: the study of a (137)Cs calibration irradiator; the manganese bath technique; the iron sphere experiment using neutron time-of-flight technique; the energy response of a RADFET detector and finally the sensitivity and uncertainty analysis for the recoil-proton telescope discussed in the companion paper.     

Quantitative microfluidic separation of DNA in self-assembled magnetic matrixes

We present an experimental study of the microfluidic electrophoresis of long DNA in self-assembling matrixes of magnetic bead columns. Results are presented for the rapid separation of lambda-phage, 2lambda-DNA, and bacteriophage T4 DNA, where separation resolutions greater than 2 between lambda and T4 are achieved in times as short as 150 s. The use of a computer-piloted flow control system and injection results in high reproducibility between separations. We compare the experimentally measured mobility and dispersion with an exactly solvable lattice Monte Carlo model. The theory predicts that the mean velocity scales linearly with the field, the band broadening scales with the inverse of the field, and the resolution is independent of the field for intermediate fields-all of which are in accord with the experimental results. Moreover, reasonable quantitative agreement is achieved for band broadening for longer DNA (2lambda and T4) when the average postengagement time is measured experimentally. This work demonstrates the possibility of achieving fast microfluidic separation of large DNA on a routine basis.     

Core/shell nanoparticles for multiple biological detection with enhanced sensitivity and kinetics

The paper shows the different methods to attach a molecule to detect streptavidin to a dielectric particle made of a rare-earth oxide core and a polysiloxane shell containing fluorescein. First, the detection of streptavidin binding on a biotinylated gold substrate can be achieved in three ways: the shift of the surface plasmon resonance of the substrate and the double luminescence (organic and inorganic) of the core/shell particle. Second, these detections are efficient even after elimination upon thermal annealing of all the undesired molecules that skew the assays. Finally, the particle that ballasts the protein enhances its binding kinetics and increases the localized surface plasmon resonance shift that detects the binding.     

Social networks and aggressive behavior: Peer support or peer rejection?

Studied social networks and aggressive behavior in school in 2 cohorts of boys and girls in the 4th and 7th grades (N?=?695). Measures of social networks yielded convergent findings. Highly aggressive subjects (both boys and girls) did not differ from matched control subjects in terms of social cluster membership or in being isolated or rejected within the social network. Peer cluster analysis and reciprocal "best friend" selections indicated that aggressive subjects tended to affiliate with aggressive peers. Even though highly aggressive children and adolescents were less popular than control subjects in the social network at large, they were equally often identified as being nuclear members of social clusters. Aggressive subjects did not differ from matched control subjects in the number of times they were named by peers as "best friend," nor did the two groups differ in the probability of having friendship choices reciprocated by peers. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mechanisms of short-term saccadic adaptation.

A number of processes have been identified that adaptively modify oculomotor control components. The adaptive process studied here can be reliably produced over a short period of time by a visual stimulus that forces postsaccadic error. This short-term adaptive process, usually termed parametric adaptation, consists of a change in response amplitude that develops progressively over 50 to 100 training stimuli. Both increases and decreases in response amplitude can be evoked by an appropriately timed and directed movement of the stimulus target, which forces postsaccadic error. Results show that a single type of training stimulus can influence movements over a broad spatial region, provided these movements are in the same direction as the training stimulus. Experiments that map the range of modification suggest that the increasing adaptive modification is achieved through an overall reduction of gain. Training stimuli that attempt to evoke both increases and decreases in the same region show a net modification equivalent to the algebraic addition of individual adaptive processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mood states and sleepiness in college students: influences of age, sex, habitual sleep, and substance use

Survey and laboratory evidence suggests several factors affecting sleep-wake patterns of college students. These factors include social and academic demands, diminution of parental guidance, reduction of total sleep time, delayed bedtime, and increased nap episodes. In this study, we examined the problem of falling asleep in school as a correlate of negative moods in this population (N = 294). A multivariate analysis showed significant main effects of sleepiness on mood states based on the Profile of Mood States. Students who fell asleep in school reported higher negative mood states. Significant interactions were observed among sleepiness and age, sex, race, and duration of sleep. Specifically, younger men reported higher negative moods. No interactions were noted for alcohol and marijuana consumption; however, students who fell asleep in school consumed more alcoholic beverages and smoked more than those who did not. Perhaps falling asleep in school could be used as an index that characterizes students who manifest adaptive or psychological difficulty.     

Behavior of Five Large Spread Footings in Sand

Five square spread footings ranging in size from 1 to 3 m were load tested up to 150 mm of settlement. They were all embedded 0.75 m into a medium dense, fairly uniform, silty silica sand. Load-settlement curves are presented, as well as creep curves relating settlement and time under a constant load. Since the soil mass was instrumented with telltales and inclinometers, vertical and horizontal movements in the soil mass were obtained as a function of depth and lateral extent. Conclusions are reached regarding how best to measure footing settlement, how to present load test results, new correlations for use in design, creep settlement, effect of cyclic loading and preloading on creep rate, zone of influence under the footing, mode of deformation of the soil mass, and volume change observations. Twelve settlement methods, six bearing capacity methods, and the WAK (wave activated stiffness) test are evaluated by comparing the predictions with the measurements. Many results of these large-scale instrumented tests confirm findings at small scale of previous researchers.     

Mesure de largeurs de trait en éclairage partiellement cohérent par modélisation du transfert et utilisation de techniques de moindres carrés

A method of transfer modelling in partially coherent microscopy is presented. By determining the minimal error between simulated and experimental data by means of a lms technique, it is then possible to retrieve, with accuracy, the linewidth on wafers.