Nursing at the crossroads

Crossroads is the term used to describe nursing's decisional grid in the post health care reform era. Four avenues of practice are laid out. Nursing's decision about clinical pathways will contribute to the future of professional nursing and help shape health care delivery.     

Gene amplification in Chinese hamster DNA repair deficient mutants

In order to study the possible relationship between gene amplification and DNA repair we analyzed the amplification of the CAD gene in four mutants hypersensitive to UV light (CHO43RO, CHO7PV, UV5 and UV61) isolated in vitro from Chinese hamster cell lines (CHO-K1 and AA8). These mutants are characterized by different defects in the nucleotide excision repair mechanism and represent complementation groups 1, 9, 2, and 6 respectively. To evaluate the amplification ability of each cell line we measured the rate of appearance of PALA resistant clones with the Luria and Delbrück fluctuation test. Resistance to PALA is mainly due to amplification of the CAD gene. In the mutants CHO43RO, UV5 and CHO7PV we reproducibly found an amplification rate lower than in the parental cell lines (2-5 times), while in UV61 the amplification rate was about 4 times higher. This result indicates that each mutant is characterized by a specific amplification ability and that the unefficient removal of UV induced DNA damage can be associated with either a higher or a lower amplification rate. However, the analysis of randomly isolated CHO-K1 clones with normal UV sensitivity has shown variability in their amplification ability, making it difficult to relate the specific amplification ability of the mutants to the DNA repair defect and suggesting clonal heterogeneity of the parental population.     

A methodology for assessing gamebird use of short rotation coppice

Gamebirds provide a considerable incentive to plant and manage new woodlands. The supplementary income thus generated can improve their overall value. Other studies suggest that Short Rotation Coppice (SRC) crops may provide an attractive habitat for some gamebird species and could increase the value of the crop. To investigate this, the use by pheasants and partridge of different types of SRC at one site was assessed.

A method using sand quadrats to record gamebird footprints and hence relative use was developed. Pheasant footprints were recorded more frequently in the quadrats alongside the willow coppice, whereas partridge footprints occurred more frequently alongside the poplar coppice. Footprint analysis offers a reliable method of investigating how gamebirds use different types of SRC within small areas. The results are considered in terms of the placement of short rotation coppice plantations in the landscape to improve their ecological design.     

Crystallographic shear planes in nanocrystalline SnO2 thin films by high-resolution transmission electron microscopy

Atomic structures of crystallographic shear planes (CSPs) in nanocrystalline thin films of semiconductor SnO₂ were investigated by high-resolution electron microscopy. The films were prepared by electron beam evaporation in high vacuum (10^–6 torr) and followed by annealing in synthetic air at 700 °C for 1–2 H. CSPs with the displacement vector of [1/2 0 1/2] were observed in the planes parallel to (¯101), (110) and (¯3¯21). Most of the CPSs were found to terminate or interact with each other within SnO₂ crystallites. Partial dislocations exist at terminal places of CSPs or along intersecting lines of CSPs. CSP steps were also observed. Structural models of these defects have been proposed. Based on analysis of experimental data, it has been suggested that the Sn/O ratio at CSPs which are not parallel to their displacement vector, at cores of partial dislocations and at CSP steps, is higher than that of the perfect structure, that is, these defects are able to provide extra free electrons with the films.     

Note on a vertical water-jet emanating downwards from a slit in the air

Summary In this study the critical dimensionless parameters, controlling the alternate 90° turn and oscillation along the axis of a vertical water-jet emanating downwards from a slit in the air are determined.     

Real-world extensions to scheduling algorithms based on lagrangian relaxation

Recently, efficient scheduling algorithms based on Lagrangian relaxation have been proposed for scheduling parallel machine systems and job shops. In this article, we develop real-world extensions to these scheduling methods. In the first part of the paper, we consider the problem of scheduling single operation jobs on parallel identical machines and extend the methodology to handle multiple classes of jobs, taking into account setup times and setup costs. The proposed methodology uses Lagrangian relaxation and simulated annealing in a hybrid framework. In the second part of the paper, we consider a Lagrangian relaxation based method for scheduling job shops and extend it to obtain a scheduling methodology for a real-world flexible manufacturing system with centralized material handling. This research was supported in part by the Office of Naval Research and the Department of Science and Technology grant N00014-93-1017.     

A typed functional extension of logic programming

A logic language is suitable for specification if it is equipped with features for data abstraction and modularization. In this paper, an effective mechanism to incorporate function and type into logic programming is presented as the means to embed data abstraction mechanism into logic programming. This incorporation is essentially based on Horn clause logic with equality and a polymorphic type system that is an extension of Mycroft and O’Keefe’s system. This paper also presents an implementation based on Warren Abstract Machine (WAM) and shows the performance, along with a comparison with WAM.     

Observers for stabilization of systems with matched uncertainty

In this article, we study the design of observer-based robust linear feedback controllers. The uncertainty, which can enterA, and either theB orC matrices, is assumed to satisfy certain matching conditions. Lyapunov techniques are used to establish sufficient conditions for stability, given an uncertainty bound. In particular, sufficient conditions are obtained that, if met, result in stabilizing controllers regardless of the size of the uncertainty entering the system matrix, as long as the standard constraints on the uncertainty entering the input or output matrices are met. As with the case of more general forms of uncertainty, the resulting observers often have high gains. To study performance, the problem of disturbance rejection is considered. Sufficient conditions are presented for obtaining control laws that stabilize the closed loop system, regardless of the size of the uncertainty entering the system matrix, while simultaneously guaranteeing arbitrarily small infinity norm for the transfer function from the plant disturbances to the outputs.     

Variable reluctance rotor structures-their influence on torqueproduction

Switched reluctance (SR) motors with differing structures are compared in terms of their torque prediction capabilities. The first structure is doubly salient with conventional laminations, also referred to as the CRS motor. The second has semiclosed stator slots and a cylindrical rotor with anisotropic magnetic properties arising from axial laminations interleaved with nonmagnetic material, also referred to as the CRR motor. The second structure has been claimed, on theoretical grounds, to be the superior structure in terms of torque per stator volume. The present comparison, based on RMS currents, concludes that the torque produced by the conventionally laminated motor is approximately 2.5 times that of the anisotropic design when the two copper losses are equalized. However, when the CRR motor has been optimized in terms of magnetic and electric loading, the CRS motor is still twice as torque productive. These results reverse the benefits previously claimed for the anisotropic motor design