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41.
When the phenotype of neurons in pre- and paravertebral sympathetic ganglia are compared, there are marked differences in NGF dependence, neuropeptide content, connectivity and electrophysiological properties. The trophic interactions that induce these differences are currently poorly understood. One explanation is that prevertebral neurons receive a second neurotrophic signal, other than NGF, from their target of innervation. If this is the case, neurons in the prevertebral ganglia should express another neurotrophin receptor, in addition to the NGF receptor (trkA). To test this prediction, the level of expression of three neurotrophin receptors, trkA, trkB and trkC, were examined in one paravertebral sympathetic ganglia, the SCG, and two prevertebral ganglia, the celiac and superior mesenteric ganglia. It was found that mRNA encoding the full-length form of the trkB receptor was barely expressed in the SCG. Significantly higher levels of full-length trkB mRNA expression were found in the prevertebral ganglia. Ligands of the trkB receptor may, therefore, contribute to the differentiation and/or survival of some prevertebral sympathetic neurons. 相似文献
42.
The research presented in this paper aims to support the decision process of appropriate technology transfer to industrially developing countries by improving a broader understanding of relationships between the key micro‐ and macroergonomics factors and the technology alternatives. The methodology involves knowledge acquisition, identifying and categorizing a holistic set of key criteria about technology transfer with respect to ergonomics. This work attempts briefly to identify factors affecting the success of technology transfer in order to reduce the potential of incompatibilities with respect to micro‐ and macroergonomics and to optimize the decision process of managers. The objective of the decision model, based on the analytic hierarchy process (AHP), determines the global priority weights for different technology alternatives and examines the critical factors and benefits, which affect the appropriateness of technology transfer. © 2007 Wiley Periodicals, Inc. Hum Factors Man 17: 1–19, 2007. 相似文献
43.
Recently, it has been shown that EDM wires undergo thermal buckling at low axial transport speeds and a series of transport instabilities at high axial transport speeds. Hence, only intermediate speeds ensure the straight wire configuration, which is needed for high-accuracy cutting. These conclusions are based on the assumption that the convective heat transfer coefficient remains piecewise constant along the length of the wire. However, a recent study on convection from a vibrating, flexible body shows that the convection coefficient becomes modal. The present study re-examines the wire stability problem with this modal effect in mind. It is shown that at low axial transport speeds, the straight wire configuration may be stable. Its stability hinges on vibration—large amplitude motion implies increased convection and increased stability from thermal buckling. At high transport speeds, the system still undergoes the reported transport instabilities. This work shows that the well-defined intermediate speed range is not so well-defined in the presence of wire vibrations. 相似文献
44.
Murphy Philip N.; Bentall Richard P.; Ryley Lisa D.; Ralley Richard 《Canadian Metallurgical Quarterly》2003,17(2):167
Admission scores from a model comprising 3 motivation factors concerning the cessation of heroin use and a confidence scale concerning postdischarge abstinence were tested for their ability to predict postdischarge outcomes in patients beginning inpatient opiate detoxification. Statistically significant prediction of abstinence from heroin 30 days after discharge and the number of heroin-free days in the 3 months following admission was based on the confidence scale and a factor concerned with externally imposed constraints on continued heroin use. The single-scale confidence measure made the largest contribution to each prediction, indicating that such scales may be potentially useful outcome predictors for postdischarge abstinence. External constraints on heroin use may not provide a basis for success in this treatment modality. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
45.
46.
We report two patients where the finding of isolated fetal hydrocephalus led to the detection of severe fetal thrombocytopenia, using fetal blood sampling. Serological investigation led to the diagnosis of fetomaternal alloimmune thrombocytopenia (FMAIT) due to anti-HPA-1a. Both women had had previous unsuccessful pregnancies probably due to FMAIT; one had had four miscarriages at 17-18 weeks' gestation. The other had had one previous pregnancy complicated by severe fetal anaemia, and eventually hydrocephalus developed and the fetus died without the diagnosis of FMAIT being considered. Subsequent pregnancies in the two women were also affected by FMAIT, but prenatal treatment, predominantly with serial fetal platelet transfusions, resulted in a successful outcome in both cases. These observations suggest that FMAIT should be suspected if there is isolated fetal hydrocephalus, unexplained fetal anaemia, or recurrent miscarriages. The accurate diagnosis of FMAIT is important because recent advances in prenatal management can improve the outcome of subsequently affected pregnancies. 相似文献
47.
Timing and causality in process algebra 总被引:4,自引:0,他引:4
There has been considerable controversy in concurrency theory between the ‘interleaving’ and ‘true concurrency’ schools.
The former school advocates associating a transition system with a process which captures concurrent execution via the interleaving
of occurrences; the latter adopts more complex semantic structures to avoid reducing concurrency to interleaving.
In this paper we show that the two approaches are not irreconcilable. We define a timed process algebra where occurrences
are associated with intervals of time, and give it a transition system semantics. This semantics has many of the advantages
of the interleaving approach; the algebra admits an expansion theorem, and bisimulation semantics can be used as usual. Our
transition systems, however, incorporate timing information, and this enables us to express concurrency: merely adding timing
appropriately generalises transition systems to asynchronous transition systems, showing that time gives a link between true
concurrency and interleaving. Moreover, we can provide a complete axiomatisation of bisimulation for our algebra; a result
that is often problematic in a timed setting.
Another advantage of incorporating timing information into the calculus is that it allows a particularly simple definition
of action refinement; this we present. The paper concludes with a comparison of the equivalence we present with those in the
literature, and an example system specification in our formalism.
Received December 20, 1993/February 23, 1995 相似文献
48.
This research develops a typology of atmospherics that contains user-identified modules and modular options for personalizing 3D virtual fashion stores. A content analysis of 46 focus group discussions (n = 170) was conducted to understand the user’s perspective for personalizing 3D virtual fashion store atmospherics. Based on three atmospheric categories (pathfinding assistant, environment, and the manner of product presentation), 17 modules and 207 modular options were identified for personalizing 3D virtual stores. This research pioneers the development of an atmospherics typology for personalizing 3D virtual shopping environments as a persuasive selling tool in the emerging field of 3D virtual reality (VR) retailing. 相似文献
49.
Sidney D'Mello Andrew Olney Claire Williams Patrick Hays 《International journal of human-computer studies》2012,70(5):377-398
We developed an intelligent tutoring system (ITS) that aims to promote engagement and learning by dynamically detecting and responding to students' boredom and disengagement. The tutor uses a commercial eye tracker to monitor a student's gaze patterns and identify when the student is bored, disengaged, or is zoning out. The tutor then attempts to reengage the student with dialog moves that direct the student to reorient his or her attentional patterns towards the animated pedagogical agent embodying the tutor. We evaluated the efficacy of the gaze-reactive tutor in promoting learning, motivation, and engagement in a controlled experiment where 48 students were tutored on four biology topics with both gaze-reactive and non-gaze-reactive (control condition) versions of the tutor. The results indicated that: (a) gaze-sensitive dialogs were successful in dynamically reorienting students’ attentional patterns to the important areas of the interface, (b) gaze-reactivity was effective in promoting learning gains for questions that required deep reasoning, (c) gaze-reactivity had minimal impact on students’ state motivation and on self-reported engagement, and (d) individual differences in scholastic aptitude moderated the impact of gaze-reactivity on overall learning gains. We discuss the implications of our findings, limitations, future work, and consider the possibility of using gaze-reactive ITSs in classrooms. 相似文献
50.
The effective thermal conductivity eff has been measured for 1.6 K for mixtures with 10–6–2. Both eff and the derived impurity mass diffusion coefficient Diso show an unexpected dependence on the height h of the fluid layer. A scaled representation of Diso leads to a purely phenomenological model involving an effective length scale, proportional to X–1 and temperature independent. The relations so obtained are consistent with the observations as well as with the observed transition curve QC(X) to non-linear behavior. 相似文献