946 resultados para Natural Sources of Ambient Noise,Localization and Tracking Systems
In vivo examination of membrane protein localization and degradation with green fluorescent protein.
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To test the utility of green fluorescent protein (GFP) as an in vivo reporter protein when fused to a membrane domain, we made a fusion protein between yeast hydroxymethylglutaryl-CoA reductase and GFP. Fusion proteins displayed spatial localization and regulated degradation consistent with the native hydroxymethylglutaryl-CoA reductase proteins. Thus, GFP should be useful in the study of both membrane protein localization and protein degradation in vivo.
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Mode of access: Internet.
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Includes indexes.
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Mode of access: Internet.
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Binder's title: Buffon's natural history.
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Mode of access: Internet.
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Mode of access: Internet.
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Purports to be a narrative, taken from the journal of Ezekiel Williams and other sources, of the wanderings of Willims, James Workman and Samuel Spencer in the western country from 1807 to 1810. The work is called a fabrication by H. M. Chittenden (American fur trade, 1902, v. 2, p. 651-656) It apparently has, however, some foundation in fact. cf. Louis Houck, Hist. of Missouri, 1908, v. 3, p. 93-94.
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Includes index.
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v. 1. Text -- v. 2. Plates.
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This thesis presents a study of the sources of new product ideas and the development of new product proposals in an organisation in the UK Computer Industry. The thesis extends the work of von Hippel by showing how the phenomenon which he describes as "the Customer Active Paradigm for new product idea generation" can be observed to operate in this Industry. Furthermore, this thesis contrasts his Customer Active Paradigm with the more usually encountered Manufacturer Active Paradigm. In a second area, the thesis draws a number of conclusions relating to methods of market research, confirming existing observations and demonstrating the suitability of flexible interview strategies in certain circumstances. The thesis goes on to demonstrate the importance of free information flow within the organisation, making it more likely that sought and unsought opportunities can be exploited. It is shown that formal information flows and documents are a necessary but not sufficient means of influencing the formation of the organisation's dominant ideas on new product areas. The findings also link the work of Tushman and Katz on the role of "Gatekeepers" with the work of von Hippel by showing that the role of gatekeeper is particularly appropriate and useful to an organisation changing from Customer Active to Manufacturer Active methods of idea generation. Finally, the thesis provides conclusions relating to the exploitation of specific new product opportunities facing the sponsoring organisation.
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Purpose: To describe the prevalence and natural history of retinopathy in a cohort of children and young people with type 1 diabetes attending a tertiary hospital diabetes clinic. Methods: We analysed retinopathy screening data from 2008 to 2010 on all eligible children using the 'Twinkle' diabetes database and the regional retinal screening database. Results: A total of 88% (149/169) of eligible children were screened in 2008, median age 14 years, 52% male. The prevalence of retinopathy was 19.5% (30/149). All children had background retinopathy grade R1. There was significant difference in median (range) duration of diabetes, 7.7 years (0.6–13.7) vs 5 years (0.2–12.5) (P<0.001) and median (range) HbA1C, 9.1% (7.2–14) vs 8.6% (5.6–13.1) (P=0.02), between the groups with and without retinopathy. At 2- years follow-up, 12/30 (40%) had unchanged retinopathy grade R1, 10/30 (33.3%) showed resolution of changes (R0), 1/30 progressed to maculopathy, and 7/30 had no follow-up data. Median (range) HbA1C in 2008 and 2010 for the groups with stable vs resolved changes was similar, 9.1% (7.2–14.0) and 9.2% (7–14.0) vs 9.5% (7.8–14.0) and 9.2% (8.7–14.0). Of the 119 without retinopathy in 2008, 27 (22.5%) had developed retinopathy within 2 years, including 1 with pre-proliferative retinopathy and 1 with maculopathy. There was no significant difference in HbA1c between those who progressed to retinopathy (8.7% (7.1–13.1)) (8.7% (7.1–13.1)), and those who did not (8.6% (6.3–12.2)). Conclusions: Prevalence of background retinopathy in our cohort was comparable to the previously published reports, with higher HbA1c and longer duration of diabetes being significant risk factors. On short-term follow-up, Grade 1 retinopathy is likely to resolve in a third of patients and remain unchanged in just over a third.
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This paper proposes a very fast method for blindly initial- izing a nonlinear mapping which transforms a sum of random variables. The method provides a surprisingly good approximation even when the basic assumption is not fully satis¯ed. The method can been used success- fully for initializing nonlinearity in post-nonlinear mixtures or in Wiener system inversion, for improving algorithm speed and convergence.
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Indoor positioning has attracted considerable attention for decades due to the increasing demands for location based services. In the past years, although numerous methods have been proposed for indoor positioning, it is still challenging to find a convincing solution that combines high positioning accuracy and ease of deployment. Radio-based indoor positioning has emerged as a dominant method due to its ubiquitousness, especially for WiFi. RSSI (Received Signal Strength Indicator) has been investigated in the area of indoor positioning for decades. However, it is prone to multipath propagation and hence fingerprinting has become the most commonly used method for indoor positioning using RSSI. The drawback of fingerprinting is that it requires intensive labour efforts to calibrate the radio map prior to experiments, which makes the deployment of the positioning system very time consuming. Using time information as another way for radio-based indoor positioning is challenged by time synchronization among anchor nodes and timestamp accuracy. Besides radio-based positioning methods, intensive research has been conducted to make use of inertial sensors for indoor tracking due to the fast developments of smartphones. However, these methods are normally prone to accumulative errors and might not be available for some applications, such as passive positioning. This thesis focuses on network-based indoor positioning and tracking systems, mainly for passive positioning, which does not require the participation of targets in the positioning process. To achieve high positioning accuracy, we work on some information of radio signals from physical-layer processing, such as timestamps and channel information. The contributions in this thesis can be divided into two parts: time-based positioning and channel information based positioning. First, for time-based indoor positioning (especially for narrow-band signals), we address challenges for compensating synchronization offsets among anchor nodes, designing timestamps with high resolution, and developing accurate positioning methods. Second, we work on range-based positioning methods with channel information to passively locate and track WiFi targets. Targeting less efforts for deployment, we work on range-based methods, which require much less calibration efforts than fingerprinting. By designing some novel enhanced methods for both ranging and positioning (including trilateration for stationary targets and particle filter for mobile targets), we are able to locate WiFi targets with high accuracy solely relying on radio signals and our proposed enhanced particle filter significantly outperforms the other commonly used range-based positioning algorithms, e.g., a traditional particle filter, extended Kalman filter and trilateration algorithms. In addition to using radio signals for passive positioning, we propose a second enhanced particle filter for active positioning to fuse inertial sensor and channel information to track indoor targets, which achieves higher tracking accuracy than tracking methods solely relying on either radio signals or inertial sensors.
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The importance of vision-based systems for Sense-and-Avoid is increasing nowadays as remotely piloted and autonomous UAVs become part of the non-segregated airspace. The development and evaluation of these systems demand flight scenario images which are expensive and risky to obtain. Currently Augmented Reality techniques allow the compositing of real flight scenario images with 3D aircraft models to produce useful realistic images for system development and benchmarking purposes at a much lower cost and risk. With the techniques presented in this paper, 3D aircraft models are positioned firstly in a simulated 3D scene with controlled illumination and rendering parameters. Realistic simulated images are then obtained using an image processing algorithm which fuses the images obtained from the 3D scene with images from real UAV flights taking into account on board camera vibrations. Since the intruder and camera poses are user-defined, ground truth data is available. These ground truth annotations allow to develop and quantitatively evaluate aircraft detection and tracking algorithms. This paper presents the software developed to create a public dataset of 24 videos together with their annotations and some tracking application results.