Singularities on the flow between two rotating surfaces

Summary Two coaxial surfaces of revolution rotate about the common axis of symmetry with almost the same angular velocity. At large Reynolds numbers, three singular surfaces are found. One over each surface of revolution and a cylindrical shear layer touching the outer surface. Outside the cylinder the velocity is determined by the velocity distribution over the two boundary layers, while inside the cylinder the fluid is at rest.With 5 Figures     

Fully developed steady flow in a slightly curved annular pipe

Summary A theoretical study of steady flow in a slightly curved annular pipe is presented. The equations of motion are expanded in powers of a non-dimensional radius ration . It is shown that the presence of the axial core affects essentially the axial flow and the wall shear stress. In addition the secondary flow is modified depending on the size of the annular gap.     

Effect of Human Behaviour in Shipboard Firefighting Decisions: The Case of Fire in Engine Rooms

This study highlights the hazards associated with the development of a fire onboard a ship, with respect to the decision‐making alternatives of its captain. In this context, a risk assessment methodology is proposed, using the AHP method, to identify the expected hazards, caused by a fire in the engine room of a ship, as a part of a contingency planning. An analysis of 77 casualties, revealed that ships aged over 15 years and/or designed to carry RO‐RO cargoes, containers, or passengers, have a relatively high frequency of fire events in their engine rooms. Furthermore, the element of time was found to be a factor, which affects the human behaviour of the captain of a ship, as fire growths.     

Social Mirrors as Social Signals: Transforming Audio into Graphics

A social mirror is a specific type of visualization for group interaction. Three examples of social mirrors emphasize different motivations for visualizing vocal conversation: the power of visualization to influence conversation in real time, the addition of anonymous input into group visualization, and idea formation over time. Social visualizations are visualizations about people, for people. A social mirror is a type of social visualization with three particular qualities. First, it's a third-person visualization in which people can see information about themselves within information about other people. In a sense, we can perceive "us and them." Every participant sees the same visualization. Second, subtle perceivable changes of any participant appear in the visualization as they occur in near real time. This can include capturing and visualizing subtle social behaviors such as laughing and coughing. Because of this near real-time feature, people can quickly alter their behavior-and hence the visualization-so that others perceive them as they'd like to be perceived in this public mirror. Third, social mirrors allow for exploring group patterns and behavior through real-time experimentation, replay, annotation, and reconfiguration.     

Induced flow in a curved tube by the oscillations of a rigid axial core

Summary When a rigid core in a curved tube of circular cross-section oscillates axially, the contained fluid acquires a composite motion that depends on the radius of the core relative to the radius of the tube and on the frequency of oscillation. For small values of the frequency, analytic solutions are derived for the axial and secondary flow, giving the flow configuration.With 4 Figures     

Flow induced by a lamina performing transverse and torsional oscillations

Summary On the assumption that a lamina performs torsional and linear oscillations of small amplitude in its own plane, an analytic solution of the Navier-Stokes equation is attempted by the method of successive approximations up to the third order. This solution leads to a steady flow outside the boundary-layer. Next it is assumed that in addition to the existing boundary-layer close to the lamina, another boundary-layer is formed, the outer layer. A numerical solution is then attempted that describes the character of the flow. This solution gives, in polar coordinates, radial and transverse velocity components decaying to zero at the outer limits of the outer layer.With 7 Figures     

Internal and External Visual Cue Preferences for Visualizations in Presentations

Presenters, such as analysts briefing to an executive committee, often use visualizations to convey information. In these cases, providing clear visual guidance is important to communicate key concepts without confusion. This paper explores visual cues that guide attention to a particular area of a visualization. We developed a visual cue taxonomy distinguishing internal from external cues, designed a web tool based on the taxonomy, and conducted a user study with 24 participants to understand user preferences in choosing visual cues. Participants perceived internal cues (e.g., transparency, brightness, and magnification) as the most useful visual cues and often combined them with other internal or external cues to emphasize areas of focus for their audience. Interviews also revealed that the choice of visual cues depends on not only the chart type, but also the presentation setting, the audience, and the function cues are serving. Considering the complexity of choosing visual cues, we provide design implications for improving the organization, consistency, and integration of visual cues within existing workflows.     

Efficacy of pedicle screw fixation in the treatment of spinal instability and failed back surgery: a 5-year review

In order to establish a large panel of normal and tumour DNA from primary breast cancer patients, we looked for a source of easily accessible, good quality breast tumour DNA. Following routine hormone receptor analysis at the hospital the leftover pellets contained the nuclei from the tumour tissue. We collected 670 pellets over a period of 2 1/4 years and isolated a large amount of DNA (on average 400 microg per pellet). To control the quality of this tumour DNA, we analysed 41 pellets and matching normal DNA for loss of heterozygosity (LOH), with 11 microsatellite markers along chromosome 17. This chromosome is well described for breast cancer. LOH is a sensitive method, requiring good quality and pure tumour DNA. Contamination with normal DNA will blur the results. We found a high rate of LOH, ranging from 33 to 74%, which is in agreement with other reports, and therefore recommend this rich source of breast tumour DNA for molecular biological analysis.     

Growth phase and growth rate dependence of ribosomal peptidyltransferase activity status in Escherichia coli

Ribosomes from a clinical isolate of E coli were purified and characterized. The structural features of these ribosomes were identical to wild-type E coli ribosomes, with the exception that rRNA in general, but especially 23S rRNA, was degraded as a result of the transition from early to late logarithmic growth phase, on different growth media. Analysis of the ribosomal protein by gel electrophoresis indicated that the L12/L7 molar ratio increases during early logarithmic phase, reaching a maximum value of about 1.6 at midlogarithmic phase, and then falling to 0.7 in late logarithmic phase. Concomitantly with L12/L7 alterations, the activity status of ribosomal peptidyltransferase was found to undergo a striking shift. Reconstitution experiments demonstrated that the two effects are closely related. Moreover, L12/L7 molar ratio as well as peptidyltransferase activity increased with increasing growth rate. In the latter case, however, the acetylation level of L12 protein per se seemed to be inadequate to modulate the peptidyltransferase activity.