This paper aims at a type of image homing guided missile. The guided trajectory characteristics and the initial condition of the homing guidance are analyzed by calculating the miss distance of the image guided missil...
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This paper aims at a type of image homing guided missile. The guided trajectory characteristics and the initial condition of the homing guidance are analyzed by calculating the miss distance of the image guided missile. Several modified proportional navigation laws which are easy for engineering implementation are introduced.
This article explores the ways in which framings drawn from post-structuralism can help to inform the understanding of guidance practices. In particular, it draws upon the later work of Foucault and Actor-Network Theo...
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This article explores the ways in which framings drawn from post-structuralism can help to inform the understanding of guidance practices. In particular, it draws upon the later work of Foucault and Actor-Network Theory to question the centrality of the humanistic subject predominant within discourses of contemporary guidance and raise issues of power, identity and artefacts in guidance practices. Through these we suggest that guidance can be reframed as a socio-technical web of spatialised knowledge-building practices within wider actions at a distance in the ordering of the social.
The revision—and revitalization—of the 1993 Food Guide Pyramid adds new dimensions to the discussion of conveying food guidance to consumers, especially with the addition of the physical activity component to the ne...
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The revision—and revitalization—of the 1993 Food Guide Pyramid adds new dimensions to the discussion of conveying food guidance to consumers, especially with the addition of the physical activity component to the new symbol. The new MyPyramid food guidance system, released on April 19, 2005, is an interactive nutrition education tool intended to help consumers apply personalized dietary guidance to achieve a healthful lifestyle. While the 2005 Dietary Guidelines for Americans, released this January, represents a comprehensive review of nutrition science and health and can serve as a blueprint for product development, MyPyramid may shift attention toward innovative package design to encourage consumers to implement the revised guidance on food choices and physical activity.
In 2001, the ACS reported, “The Ph.D. in chemistry usually prepares individuals for careers in basic research. The degree does not typically prepare these highly skilled research professionals to be faculty members....
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In 2001, the ACS reported, “The Ph.D. in chemistry usually prepares individuals for careers in basic research. The degree does not typically prepare these highly skilled research professionals to be faculty members.” In 2004, a report of a workshop held at NSF noted that “the purpose of the postdoctoral experience should … prepare postdocs for professional careers that are not solely as faculty members at research-intensive universities.” For the past 10 years the UCLA Chemistry and Biochemistry department has addressed these issues through a Preparing Future Faculty (PFF) course for Ph.D. students and postdoctoral scholars. To assess the long-term impact of the course, a questionnaire was sent to 91 people with whom we still had contact information and who had participated in the program between 1994 and 2002. From the 41% response rate, 86% (32) identified themselves as being in academic positions from the full range of types of higher education institutions. The survey revealed that all components of the seminar were helpful for the academic recruitment process and that some aspects continued to be useful for the respondents in their current faculty positions.
A hybrid guiding liquid-crystal photonic crystal fiber is proposed, in which two polarization components (E-chi and E-y) are confined by modified total internal reflection and bandgap guidance, respectively. With the ...
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A hybrid guiding liquid-crystal photonic crystal fiber is proposed, in which two polarization components (E-chi and E-y) are confined by modified total internal reflection and bandgap guidance, respectively. With the aid of scalar wave approximation, the distinct features in band structures of liquid-crystal photonic bandgap fibers are successfully identified. This hybrid guiding feature makes it possible to achieve single-polarization singlemode guiding and high birefringence guiding effects in different wavelength ranges. Particularly, high hirefringence of an order of 10(-2) can be easily obtained.
The goal of this study was the development of a bioartificial nerve guide to induce axonal regeneration in the peripheral nervous system (PNS). In this in vitro study, the ability of a novel, 3-dimensional (3D), highl...
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The goal of this study was the development of a bioartificial nerve guide to induce axonal regeneration in the peripheral nervous system (PNS). In this in vitro study, the ability of a novel, 3-dimensional (3D), highly oriented, cross-linked porcine collagen scaffold to promote directed axonal growth has been studied. Collagen nerve guides with longitudinal guidance channels were manufactured using a series of chemical and mechanical treatments with a patented unidirectional freezing process, followed by freeze-drying (pore sizes 20-50 mu m). Hemisected rat dorsal root ganglia (DRG) were positioned such that neural and non-neural elements could migrate into the collagen scaffold. After 21 days, S100-positive Schwann cells (SCs) migrated into the scaffold and aligned within the guidance channels in a columnar fashion, resembling "Bands of Bungner." Neurofilament-positive axons (mean length +/- SD 756 mu m +/- 318 mu m, maximum 1496 mu m) from DRG neurons entered the scaffold where the growth within the guidance channels was closely associated with the oriented SCs. This study confirmed the importance of SCs in the regeneration process (neurotrophic theory). The alignment of SCs within the guidance channels supported directional axonal growth (contact guidance theory). The microstructural properties of the scaffold (open, porous, longitudinal pore channels) and the in vitro data after DRG loading (axonal regeneration along migrated and columnar-aligned SCs resembling "Band of Bungner") suggest that this novel oriented 3D collagen scaffold serves as a basis for future experimental regeneration studies in the PNS.
A fast, robust, accurate, and automatic registration technique based on magnetic resonance (MR) active microcoils (active markers) for registration of tracked medical devices to preprocedural MR-images is presented. T...
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A fast, robust, accurate, and automatic registration technique based on magnetic resonance (MR) active microcoils (active markers) for registration of tracked medical devices to preprocedural MR-images is presented. This allows for a straightforward integration of position measurement systems into clinical procedures. The presented method is useful for guidance purposes in clinical applications with high demands on accuracy and ease-of-use (e.g., neurosurgical or orthopedic applications). The determination of the positions of the active markers is integrated into the preparation phase of the actual MR imaging scan. The technique features a generic interface using DICOM standards for communication with navigation workstations linked to an MR system. The position of the active markers is fixed with respect to a reference system of an optical positioning measurement system (OPMS) and thus the coregistration of the MR system and the OPMS is established. In a phantom study, a mean overall targeting accuracy of 0.9 +/- 0.1 mm was achieved and compared favorably to results obtained from manual registration tests (1.8 +/- 0.3 mm) carried out in parallel. For a test person trained for both registration methods, workflow improvements of 3-6 min per registration step were found. The need for manual interaction is entirely eliminated thus avoiding user-bias, which is advantageous for the usage in clinical routine. The method improves the ease-of-use of tracking equipment during stereotactic guidance. The method is finally demonstrated in a volunteer study using a model of a Mayfield skull clamp with integrated active and optical reference markers.
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