Computer simulation of macrosegregation in directionally solidified circular ingots

The formulation and employment of a computer code designed to simulate the directional solidification of lead-rich Pb-Sn alloys in the form of an ingot with a uniform and circular cross-section are described. The formulation is for steady-state solidification in which convection in the all-liquid zone is ignored. Particular attention was given to designing a code to simulate the effect of a subtle variation of temperature in the radial direction. This is important because a very small temperature difference between the center and the surface of the ingot (e.g., less than 0.5 C ) is enough to cause substantial convection within the mushy-zone when the solidification rate is approximately 0.001 to 0.0001 cm/s

Using Implicit Instructional Cues to Influence False Memory Induction

Previous research has shown that explicit cues specific to the encoding process (endogenous) or characteristic of the stimuli themselves (exogenous) can be used to direct a reader’s attentional resources towards either relational or item-specific information. By directing attention to relational information (and therefore away from item-specific information) the rate of false memory induction can be increased. The purpose of the current study was to investigate if a similar effect would be found by manipulating implicitly endogenous cues. An instructional manipulation was used to influence the perceptual action participants performed on word stimuli during the encoding of DRM list words. Results demonstrated that the instructional conditions that encouraged faster processing also led to an increased rate of false memory induction for semantically related words, supporting the hypothesis that attention was directed towards relational information. This finding supports the impoverished relational processing account of false memory induction. This supports the idea that implicitly endogenous cues, exogenous cues (like font) or explicitly endogenous cues (like training) can direct attentional resources during encoding

Retrospective and prospective evaluations of mammography screening narratives: The role of own experience

We investigated the role of previous experience when providing summary judgments of mammography narratives. A total of 807 women who either did or did not have previous experience of a mammogram were presented with a written description of a mammography visit. We manipulated the presentation position of a negative element within the narrative to alter its accessibility in memory and determine whether the latter impacted equally on two types of summary judgments. After the narrative presentation, participants were asked to provide both retrospective and prospective evaluations, that is, summary judgments about the described event and an appraisal of the likelihood of participating in future instances of such event, respectively. A recency effect was observed only for retrospective but not for prospective evaluations. When examined only for the subset of women who had undergone a mammography visit themselves, prospective evaluations were shown to be predicted by the reported quality of the mammography participants experienced themselves. The findings support and extend the accessibility model of emotional self-report and suggest that own experience leaks into evaluations of hypothetical scenarios by selectively impacting on prospective evaluations

Search for Sub-TeV Gamma Rays Coincident with BATSE Gamma Ray Bursts

Project GRAND is a 100m x 100m air shower array of proportional wire chambers (PWCs). There are 64 stations each with eight 1.29 m^2 PWC planes arranged in four orthogonal pairs placed vertically above one another to geometrically measure the angles of charged secondaries. A steel plate above the bottom pair of PWCs differentiates muons (which pass undeflected through the steel) from non-penetrating particles. FLUKA Monte Carlo studies show that a TeV gamma ray striking the atmosphere at normal incidence produces 0.23 muons which reach ground level where their angles and identities are measured. Thus, paradoxically, secondary muons are used as a signature for gamma ray primaries. The data are examined for possible angular and time coincidences with eight gamma ray bursts (GRBs) detected by BATSE. Seven of the GRBs were selected because of their good acceptance by GRAND and high BATSE Fluence. The eighth GRB was added due to its possible coincident detection by Milagrito. For each of the eight candidate GRBs, the number of excess counts during the BATSE T90 time interval and within plus or minus five degrees of BATSE's direction was obtained. The highest statistical significance reported in this paper (2.7 sigma) is for the event that was predicted to be the most likely to be observed (GRB 971110).Comment: To be presented at the XXVIII International Cosmic Ray Conference, Tsukuba, Japa

Simulation studies and background measurements for a laser based beam size monitor for the future linear collider

At several locations of the beam delivery system (BDS) of a future linear collider (FLC), beam spot sizes ranging from several hundreds to a few micrometers have to be measured. It is anticipated that laser wires will be used for this task in any FLC design. In order to optimize a laser wire system, simulations and background measurements have been carried out. Results are presented from simulations of the Compton scattering for the PETRA scenario. Furthermore results from measurements of backgrounds like synchrotron radiation and gas scattering have been measured at the positron storage ring PETRA at DESY and will be discussed

Mott Transition, Compressibility Divergence and P-T Phase Diagram of Layered Organic Superconductors: An Ultrasonic Investigation

The phase diagram of the organic superconductor $\kappa$-(BEDT-TTF)$_2$Cu[N(CN)$_2$Cl has been investigated by ultrasonic velocity measurements under helium gas pressure. Different phase transitions were identified trough several elastic anomalies characterized from isobaric and isothermal sweeps. Our data reveal two crossover lines that end on the critical point terminating the first-order Mott transition line. When the critical point is approached along these lines, we observe a dramatic softening of the velocity which is consistent with a diverging compressibility of the electronic degrees of freedom.Comment: 4 pages, 5 figure

Assessing the Influence of Letter Position in Reading Normal and Transposed Texts Using a Letter Detection Task

During word recognition, some letters appear to play a more important role than others. Although some studies have suggested that the first and last letters of a word have a privileged status, there is no consensus with regards to the importance of the different letter positions when reading connected text. In the current experiments, we used a simple letter search task to examine the impact of letter position on word identification in connected text using a classic paper and pencil procedure (Experiment 1) and an eye movement monitoring procedure (Experiment 2). In Experiments 3 and 4, a condition with transposed letters was included. Our results show that the first letter of a word is detected more easily than the other letters, and transposing letters in a word revealed the importance of the final letter. It is concluded that both the initial and final letters play a special role in word identification during reading but that the underlying processes might differ