A movable stop mechanism for the SIRE telescope

A movable stop mechanism (MSM) designed to activate flaps that change the size and shape of a telescope aperture stop on command is described. Operating at the cryogenic temperatures of the optical system, it consists primarily of a rotary solenoid that drives (activates) dual four-bar linkages in synchronism that in turn rotate the butterfly flaps into position. The design, performance characteristics, and testing of this mechanism are discussed. Specific problems that occurred during testing and the solutions that were adopted are also described

Longwall shearer tracking system

A tracking system for measuring and recording the movements of a longwall shearer vehicle includes an optical tracking assembly carried at one end of a desired vehicle path and a retroreflector assembly carried by the vehicle. Continuous horizontal and vertical light beams are alternately transmitted by means of a rotating Dove prism to the reflector assembly. A vertically reciprocating reflector interrupts the continuous light beams and converts these to discrete horizontal and vertical light beam images transmitted at spaced intervals along the path. A second rotating Dove prism rotates the vertical images to convert them to a second series of horizontal images while the first mentioned horizontal images are left unrotated and horizontal. The images are recorded on a film

Conflicting priorities: evaluation of an intervention to improve nurse-parent relationships on a Tanzanian paediatric ward.

BACKGROUND: Patient, or parent/guardian, satisfaction with health care provision is important to health outcomes. Poor relationships with health workers, particularly with nursing staff, have been reported to reduce satisfaction with care in Africa. Participatory research approaches such as the Health Workers for Change initiative have been successful in improving provider-client relationships in various developing country settings, but have not yet been reported in the complex environment of hospital wards. We evaluated the HWC approach for improving the relationship between nurses and parents on a paediatric ward in a busy regional hospital in Tanzania. METHODS: The intervention consisted of six workshops, attended by 29 of 31 trained nurses and nurse attendants working on the paediatric ward. Parental satisfaction with nursing care was measured with 288 parents before and six weeks after the workshops, by means of an adapted Picker questionnaire. Two focus-group discussions were held with the workshop participants six months after the intervention. RESULTS: During the workshops, nurses demonstrated awareness of poor relationships between themselves and mothers. To tackle this, they proposed measures including weekly meetings to solve problems, maintain respect and increase cooperation, and representation to administrative forces to request better working conditions such as equipment, salaries and staff numbers. The results of the parent satisfaction questionnaire showed some improvement in responsiveness of nurses to client needs, but overall the mean percentage of parents reporting each of 20 problems was not statistically significantly different after the intervention, compared to before it (38.9% versus 41.2%). Post-workshop focus-group discussions with nursing staff suggested that nurses felt more empathic towards mothers and perceived an improvement in the relationship, but that this was hindered by persisting problems in their working environment, including poor relationships with other staff and a lack of response from hospital administration to their needs. CONCLUSION: The intended outcome of the intervention was not met. The priorities of the intervention--to improve nurse-parent relationships--did not match the priorities of the nursing staff. Development of awareness and empathy was not enough to provide care that was satisfactory to clients in the context of working conditions that were unsatisfactory to nurses

Coherence Properties of Guided-Atom Interferometers

We present a detailed investigation of the coherence properties of beam splitters and Mach-Zehnder interferometers for guided atoms. It is demonstrated that such a setup permits coherent wave packet splitting and leads to the appearance of interference fringes. We study single-mode and thermal input states and show that even for thermal input states interference fringes can be clearly observed, thus demonstrating the multimode operation and the robustness of the interferometer.Comment: 4 pages, 4 figure

Pyramidal Atoms: Berylliumlike Hollow States

Based on the idea that four excited electrons arrange themselves around the nucleus in the corners of a pyramid in order to minimize their mutual repulsion, we present an analytical model of quadruply excited states. The model shows excellent comparison with ab initio results and provides a clear physical picture of the intrinsic motion of the four electrons. The model is used to predict configuration-mixing fractions and spectra of these highly correlated states.Comment: 4 pages, 2 figure

Neural mechanisms of resistance to peer influence in early adolescence

During the shift from a parent-dependent child to a fully autonomous adult, peers take on a significant role in shaping the adolescent’s behaviour. Peer-derived influences are not always positive, however. Here we explore neural correlates of inter-individual differences in the probability of resisting peer influence in early adolescence. Using functional magnetic-resonance imaging (fMRI), we found striking differences between 10-year old children with high and low resistance to peer influence in their brain activity during observation of angry hand-movements and angry facial expressions: compared with subjects with low resistance to peer influence, individuals with high resistance showed a highly coordinated brain activity in neural systems underlying perception of action and decision making. These findings suggest that the probability of resisting peer influence depends on neural interactions during observation of emotion-laden actions

Factors that inhibit snowball Earth simulation

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94616/1/palo1176.pd