Within an axon bundle, one or two are pioneering axons and the rest are follower axons. Pioneering axons are projected first and the follower axons are projected later but follow a pioneering axon(s) pathway. It is no...
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Within an axon bundle, one or two are pioneering axons and the rest are follower axons. Pioneering axons are projected first and the follower axons are projected later but follow a pioneering axon(s) pathway. It is not clear whether the pioneering axons have a guidance role for follower axons. In this paper, we have investigated the role of Patched (Ptc) in regulating the guidance of medial tract, one of the longitudinal tracts in the nerve cord. In patched mutants the medial longitudinal tract fails to fasciculate on its own side along the nerve cord, instead it abnormally crosses the midline and fasciculates with the contralateral tract. Interestingly, the medial tracts cross the midline ignoring the axon-repellant Slit on the midline and Roundabout on growth cones. The medial tract is pioneered by neurons pCC and vMP2. Our results show that guidance defects of this tract are due to loss and mis-specification of vMP2, which results in the projection from pCC to either stall or project outward near the location of vMP2. Thus, both pioneering neurons are necessary for the proper guidance of pioneering and follower axons. We also show that the loss of Ptc activity in the neuroectoderm prior to the formation of S1 and S2 neuroblasts causes the majority of axon guidance defects. These results provide insight into how mis-specification and loss of neurons can non-autonomously contribute to defects in axon pathfinding.
Background Advising on ill-health retirement is an important role of most practising occupational physicians. In recent years, the eligibility criteria and process for gaining early retirement benefits have changed in...
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Background Advising on ill-health retirement is an important role of most practising occupational physicians. In recent years, the eligibility criteria and process for gaining early retirement benefits have changed in many pension schemes in the UK. Aim To investigate the variation in rates of retirement due to ill-health in National Health Service (NHS) Trusts and Local Authorities and to update previously published guidance on ill-health retirement with specific reference to pension schemes with eligibility criteria that include permanence of incapacity due to ill-health. Methods Rates of retirement were calculated for 222 NHS Trusts and 132 Local Authorities with more than 1500 employees. Literature searches and consensus statements by the authors. Results Rates of retirement were widely distributed in the NHS Trusts and Local Authorities. The median rates of retirement were 2.11 (IQR 1.37-2.91)/1000 active members and 4.10 (IQR 3.01-6.10)/1000 employees, respectively (P < 0.001). Difficulties in the doctor-patient relationship and in ascertaining the true functional ability of some patients were identified. Conclusion There continues to be marked variation in rates of early retirement due to ill-health within and between organizations that warrants further investigation. The general and specific guidance that appears as an appendix in Supplementary data to this paper should help occupational physicians to make equitable recommendations when assessing applications for early retirement benefits and fitness to work.
At present, interventional procedures, such as stent placement, are performed under X-ray image guidance. Unfortunately with X-ray imaging, both patient and interventionalist are exposed to ionising radiation. Further...
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At present, interventional procedures, such as stent placement, are performed under X-ray image guidance. Unfortunately with X-ray imaging, both patient and interventionalist are exposed to ionising radiation. Furthermore, X-ray imaging is lacking soft tissue contrast and is not capable of true 3-D displays of either interventional device or tissue morphology. Magnetic resonance imaging (MRI) offers excellent soft tissue contrast, 3-D acquisition techniques, as well as rapid image acquisition and reconstruction. Despite these advantages, MR-guided interventions are challenging owing to the limited access to the patient, strong magnetic and radio-frequency fields that require special interventional devices, inferior image frame rates and spatial resolution, and high MRI scanner noise. For MR-guided intravascular interventions, where access to the target organ is achieved through catheters, dedicated hardware and automated image slice positioning techniques have been developed. We illustrate that MR-guided renal embolisations can be performed in closed-bore high-field MR scanners.
Global Positioning System (GPS) based guidance and automated steering systems have driven technology adoption due to the many real benefits and demonstrated payback for the investment. As this adoption grows, new farm...
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ISBN:
(纸本)9076998698
Global Positioning System (GPS) based guidance and automated steering systems have driven technology adoption due to the many real benefits and demonstrated payback for the investment. As this adoption grows, new farming practices are being discovered. In addition, traditional site-specific precision agricultural tasks are being considered by farmers because the incremental cost for them to test more precision tasks is low after they have invested in GPS guidance or steering systems. This paper explores these trends in the industry.
The following paper is written in memory of my father, Walter Rotman. In the paper, we review several of his well known inventions such as the sandwich wire antenna, plasma simulation via rodded media and the Rotman l...
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ISBN:
(纸本)9781424420414
The following paper is written in memory of my father, Walter Rotman. In the paper, we review several of his well known inventions such as the sandwich wire antenna, plasma simulation via rodded media and the Rotman lens. His work has found its way into many modem systems in which the author participated. The author would like to acknowledge his inspiration and guidance.
The use of pharmacoeconomic tool has grown dramatically in the past decade as the provision of healthcare throughout the industrialized world has required increased cost ***,pharmacoeconomic analysis has not yet been ...
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The use of pharmacoeconomic tool has grown dramatically in the past decade as the provision of healthcare throughout the industrialized world has required increased cost ***,pharmacoeconomic analysis has not yet been fully exploited as a conceptual underpinning for public and private health policy decision in *** this article,we will demonstrate why pharmacoeconomics should become an increasingly important tool for health decision making as a number of significant dynamics,including:(ⅰ)high price of pharmaceuticals;(ⅱ)misuse of pharmaceuticals;and(ⅲ)need of pharmaceutical ***,there are also some issues that hinder the sufficient utilization of pharmacoeconomics in healthcare decision making among all levels,such as insufficient experts,influence of pharmacoeconomics and lack of ***,pharmacoeconomics should be introduced into health reform and some efforts should be done to assist domestic decision makers to enhance the continual development and sufficient utilization of pharmacoeconomics in healthcare decision-making in China.
Oligodendrocytes, the myelinating cells of the central nervous system (CNS), originate early in the formation of the brain in specific foci, and migrate throughout the parenchyma. The instructional cues guiding the mi...
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Oligodendrocytes, the myelinating cells of the central nervous system (CNS), originate early in the formation of the brain in specific foci, and migrate throughout the parenchyma. The instructional cues guiding the migration of these progenitor cells must be encoded into their developing environment. Soluble factors as well as membrane-bound cues most likely synergize to create a complex thoroughfare needed to sculpt and organize the brain into a functional organ with white and gray matter. Classically, the focus of many guidance related studies in the CNS has been limited to neuron physiology. However, It is becoming increasingly clear that their lifelong partners, oligodendrocytes, express both ligands and receptors able to both present and respond to these classical cues. In this short review, some recent findings in the Semaphorin and Eph fields will be presented with respect to oligodendrocyte expression and function.
New guidance laws derived for a dual-control missile are studied. Their performance is compared with that of a conventional guidance system with flight control that distributes the commands among the two control chann...
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New guidance laws derived for a dual-control missile are studied. Their performance is compared with that of a conventional guidance system with flight control that distributes the commands among the two control channels. A Monte Carlo simulation study is performed where the target executes random evasive manoeuvres. The interceptor, represented by linear high-order manoeuvring dynamics with bounded forward and aft controls, acquires noisy measurements and uses a state estimator. Using the single-shot kill probability as a performance criterion, the superiority of the new guidance and control architecture is shown. It is also shown that the best performance is obtained by the bounded controls differential game guidance law. Sensitivity to the selection of the interceptor first-order time constant, a design parameter in the guidance law derivation, is also investigated.
The analytical closed form solution of the equations of motion of a missile tracking a non-maneuvering target using the Pure Proportional Navigation (PPN) law based on an estimate of line-of-sight (LOS) rate is presen...
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The analytical closed form solution of the equations of motion of a missile tracking a non-maneuvering target using the Pure Proportional Navigation (PPN) law based on an estimate of line-of-sight (LOS) rate is presented. The solution is obtained in the form of a uniformly convergent series of functions in polar coordinates for navigation constants N >= 2. The effect of error bounds of the estimator on the closed loop solution is presented, in line with the approach of Becker [1].
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