Posturography does not test vestibulospinal function

The clinical usefulness of posturography is unknown, despite its costing more than +500 per test in some areas of the United States, including Boston. We cross-sectionally and prospectively studied blinded vestibulo-ocular and vestibulospinal tests from 29 stable patients with chronic vestibular hypofunction; 22 patients were affected bilaterally (BVH), and 7 were affected unilaterally (UVH). Vestibulo-ocular function was assessed by electronystagmographic caloric stimulation and sinusoidal vertical axis rotation gains at 0.05 Hz. Vestibulospinal function was assessed by moving-platform and visualsurround posturography sensory organization tests (SOTs), paced and free gait in a gait laboratory, and clinical tests of timed gait and standing. Posturography SOT moving-platform tests 4 through 6, designed to assess vestibular function, correlated significantly (r < or = 0.72, P > or = 0.01) with vestibulo-ocular tests in 5 of 6 comparisons among BVH patients. Posturography SOT results, however, correlated poorly with other vestibulospinal measures: correlations were statistically significant for only 7 of 18 comparisons with clinical balance and gait function (r < or = 0.69, P > or = 0.01) and with 2 of 12 comparisons for gait laboratory dynamic stability measures (r < or = 0.55, P > or = 0.01) among the BVH patients. When both the platform and visual surround moved (SOT 6), however, correlations were statistically significant with static standing clinical measures (r = 0.51 to 0.69, P < 0.01) and with whole-body maximum moment arm during paced gait (r = 0.55, P < 0.01). Posturography scores for the UVH patients did not significantly correlate with any vestibulo-ocular or other vestibulospinal measures. These data indicate that among patients with BVH posturography SOT scores relate at best modestly with accepted measure of vestibulo-ocular function, less well with clinical measures of balance control, and poorly with dynamic gait-performance measures. We conclude that posturography SOT does not assess vestibulospinal function.     

The action plan against repetitive work— An industrial relation strategy for improving the working environment

The Danish Action Plan against Repetitive Work is presented and discussed as a possible new strategy for regulating repetitive work as well as other complicated working environment problems. The article is based on an empirical evaluation of the Action Plan. The assessment of the Action Plan indicates that a measurable reduction of repetitive work has been achieved, while recognizing that new management strategies focusing on human resource development have also played an important role. These results are used to suggest that—under certain conditions—a combination of state regulation and industrial relation agreements can be used to regulate other working environment problems. © 2001 John Wiley & Sons, Inc.     

Epidemic Simulation for Training in Public Health Management

Epidemiological simulation models to be used primarily to augment the teaching of epidemiology to medical students and other individuals concerned with public health and control of epidemics are presented. Interactive simulations are used to expose students to ``realistic' epidemic situations and permit them to experiment with various control strategies. Criteria by which simulations for such teaching purposes may be evaluated are proposed and operating simulations, MEASLES and INFLU, are described in detail. Information is provided regarding user experience with the above simulations.     

Characterisation of the aroma of green Mexican coffee and identification of mouldy/earthy defect

The aromas of a reference green Mexican coffee (Arabica) and of a coffee from the same origin, but having a pronounced earthy/mouldy off-taint, were characterised. From comparison of the two aroma profiles, the compounds causing the defect were detected by gas chromatography olfactometry, isolated and concentrated by preparative bi-dimensional gas chromatography, and characterised by gas chromatography-mass spectrometry. Six compounds participated in the off-flavour. Geosmin, 2-methylisoborneol, 2,4,6-trichloroanisole were found to be the main culprits, while three methoxy pyrazines (2-methoxy-3-isopropyl/-3-sec-butyl/-3-isobutyl pyrazine) contributed to a lesser extent to the earthy/green undertone. The occurrence of the off-flavour could tentatively be linked to post-harvest drying.     

Applicability of X-ray reflectometry to studies of polymer solar cell degradation

Although degradation of polymer solar cells is widely acknowledged, the cause, physical or chemical, has not been identified. The purpose of this work is to determine the applicability of X-ray reflectometry for in situ observation of physical degradation mechanisms. We find that the rough interfaces of the polymer solar cell constituent layers seriously obstruct the sensitivity of the technique, rendering it impossible to elucidate changes in the layer/interface structure at the sub-nanometer level.     

Group conversion versus group expansion as modes of change in majority and minority positions: All losses hurt but only some gains gratify.

This study examined reactions to minority and majority positions that were either stable or reversed through group conversion that transformed opponents (supporters) of the minority (majority) into supporters, (opponents) or through group expansion that brought new supporters (opponents) for the minority (majority) into the group. Minorities who became majorities through group expansion, compared with those who changed through group conversion, perceived their supporters and the overall group as significantly more similar to the self, and had significantly higher expectations for future positive interactions within the group. Perception of similarity with the supporters mediated the effect of the experimental conditions on perception of the overall group-self similarity. Implications of changes through conversion and expansion for the functioning of social groups are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

High frequency characteristics of InAs/GaInAs quantum dotdistributed feedback lasers emitting at 1.3 μm

The high frequency properties of InAs/GaInAs quantum dot distributed feedback (DFB) lasers emitting at 1.3 μm have been examined. The lasers display a small static linewidth of 1.3 MHz and a chirp as low as 83 MHz/mA. More than 5 GHz small-signal modulation bandwidth was observed in the first devices indicating the potential for high-speed operation of quantum dot lasers     

New Strategy for Optimizing Water Application under Trickle Irrigation

The determination of water application parameters for creating an optimal soil moisture profile represents a complex nonlinear optimization problem which renders traditional optimization into a cumbersome procedure. For this reason, an alternative methodology is proposed which combines a numerical subsurface flow model and artificial neural networks (ANN) for solving the problem in two, fully separate steps. The first step employs the flow model for calculating a large number of wetting profiles (output), obtained from a systematic variation of both water application and initial soil moisture (input). The resulting matrix of corresponding input/output values is used for training the ANN. The second step, the application of the fully trained ANN, then provides the irrigation parameters which range from a specified initial soil moisture to a desired crop-specific soil moisture profile. In order to avoid substantial disadvantages associated with the common feedforward backpropagation approach, a self-organizing topological feature map is implemented to perform this task. After a comprehensive sensitivity analysis, the new methodology is applied to the outcome of an irrigation experiment. The convincing results recommend the new methodology as a positive contribution towards an improved irrigation efficiency.