Hyperbanana Graphs

A bar-and-joint framework is a finite set of points together with specified distances between selected pairs. In rigidity theory we seek to understand when the remaining pairwise distances are also fixed. If there exists a pair of points which move relative to one another while maintaining the given distance constraints, the framework is flexible; otherwise, it is rigid. Counting conditions due to Maxwell give a necessary combinatorial criterion for generic minimal bar-and-joint rigidity in all dimensions. Laman showed that these conditions are also sufficient for frameworks in R^2. However, the flexible "double banana" shows that Maxwell's conditions are not sufficient to guarantee rigidity in R^3. We present a generalization of the double banana to a family of hyperbananas. In dimensions 3 and higher, these are (infinitesimally) flexible, providing counterexamples to the natural generalization of Laman's theorem

Space station Platform Management System (PMS) replanning using resource envelopes

One of the responsibilities of the Space Station Platform Management System (PMS) is to maintain constraint-free, short-term plans for platform and free-flyer activities. Both the replanning function and the associated constraint-checking function are viewed as potentially requiring expert system assistance. The PMS Resource Envelope Scheduling System (PRESS) expert system, which is currently under development, is described. The PRESS capabilities will include the following: plan, replan, and perform constraint checking using resource envelopes resembling those required for telescience; initialize itself using the results fo a previous run; infer the replanning needs associated with a change in resource availability; allow the user to determine the level of interaction (including an advisory capability) with the system during execution; and generate both a graphic timeline and a report as output. The PRESS is being developed on an IBM PC/AT using TeKnowledge, Inc.'s M.1 expert system shell. The PRESS activity definitions and constraints are based on those defined for the Cosmic Background Explorer (COBE) mission scheduled for launch in early 1989

Negotiating Part-Time Work: An Examination of How Attorneys Negotiate Part-Time Arrangements at Elite Law Firms

This article first provides background information pertaining to recent research on gender in negotiation and prior studies on part-time work at law firms. The author then discusses the methodology and sample of the current study of part-time work arrangements of attorneys at elite law firms in one major metropolitan legal market. Next the article describes the current study\u27s results with respect to whether attorneys viewed this situation as an opportunity to negotiate, measured by their preparation, and whether attorneys\u27 approaches were impacted by the existence of objective criteria, viewed here as the firm\u27s part-time policy. The author then provides prescriptive advice to attorneys and law firms based on the results of the current study

Mammary Tumour Development in BR6 Mice: Ovarian Influences and 5-Hydroxytryptamine

Pregnancy-dependent mammary tumours in BR6 mice first appeared during the third week of pregnancy. Regressed tumours reappeared chiefly during the second week. Alkaline Phosphatase activity in normal mammary tissue indicated a uniform increase in growth during pregnancy with no marked increase at any particular time. Pseudopregnancy was not sufficient to induce new tumours, though it had some stimulating effect on existing, regressed ones. 5-Hydroxy-tryptamine did not cause tumours in virgin mice, but seemed to influence tumour appearance in breeding females. Its possible mode of action is discussed

The Pupillometer in Practice: Identifying and Overcoming Barriers

Problem: The pupillometer is an assessment tool that provides an accurate assessment of pupil reactivity. It is appropriate for patients who are neurologically impaired due to injury or illness. This tool, available and in use at a local community hospital, has minimal perceived importance in the Neuroscience Intensive Care Unit (NSICU), due to a disconnect experienced by the staff. The hypothesis was that understanding the pupillometer information was insufficient and that improving the knowledge would increase the perception of usefulness. Method: Conduct a survey to determine the cause of the lack of interest and use of the pupillometer. Once the survey is complete, provide education for the staff based on gaps of knowledge identified in the survey and subsequently re-survey the group. Compare the two surveys to determine if the understanding of the information provided improves with the perceived value of the information. Results: Sixty nurses participated in the study. The responses assisted in identifying causes of resistance to the pupillometer and gaps in the knowledge of the information it provides. This enabled the staff to start to overcome the barriers. Conclusion: The research findings can assist nursing units with conversion of new technology that is met with resistance or a perceived lack of value, when the tool itself is proven to benefit either patient or staff in delivering care

Design and Development of Modules to Support Live Microscopic Imaging on Ground-Based Microgravity Simulators

In space, astronauts are exposed to environmental stressors that often result in physiological changes. One prominent stressor in spaceflight is microgravity, and research has shown that long term microgravity exposure causes muscle atrophy, bone loss, cardiovascular concerns, and vision impairment. It is critical to understand how altered gravity affects physiology on the cellular, molecular, and gene level in order to accurately assess health risks and to develop effective countermeasures. Ground-based microgravity simulators such as random positioning machines (RPMs) are used to produce some of the biological effects of altered gravity on different cell types and organisms. Real-time imaging during simulations are of particular interest as we can study how basic cell functions such as cell division, cell migration, and proliferation progress under microgravity conditions. However, design limitations of present microgravity simulators such as susceptibility to parasitic vibration and displacement of the sample from the center of rotation challenge the accuracy of experiment results and live images. We have developed a cell culture sample holder module suitable for live microscopic imaging on an RPM. CAD modeling and 3D printing technology were used to implement modifications to the sample holder and to install a digital microscope to perform live bright-field and fluorescent imaging. Vibration damping materials were also investigated to allow for stable imaging while the microgravity simulator was within a cell culture incubator. Novel methods and hardware modifications for improving live cell imaging on ground-based microgravity simulators were proposed and discussed

Saint-Césaire-de-Gauzignan – Le Moulinas

Ces travaux s’inscrivent dans une volonté de localisation d’un ou plusieurs gisements archéologiques à partir de découvertes fortuites, au sein d’une zone géographique pour laquelle la carte archéologique ne fournit aucune donnée. Les terrains concernés se trouvent dans un paysage agricole (vignes et blés) légèrement vallonné qui s’étend autour de la confluence de deux rivières, la Candouillère et la Droude. Géologiquement, les sols prospectés sont en grande partie composés d’alluvions récent..