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71.
72.
A feasibility study is made of the multiple free-moment dipole equivalent cardiac source concept as applied to the inverse problem in electrocardiology. The study deals with a bounded homogeneous model of a dog from which extensive geometry and potential measurements were taken. Torso surface potentials are related to the dipole sources through a set of 268 overdetermined linear algebraic equations. Three source configurations are modeled, 76, 20, and 9 dipoles, and simulation studies are made to evaluate the performance of the models and the feasibility of the concept. Inverse solutions are determined subject to a least-squares error fit of the infinite medium potentials. It is found that the number of free dipoles that can be used as an inverse source model is limited by the solution noise sensitivity, and that the upper limit is in the neighborhood of twenty. The results show that the solutions are unstable in the presence of small geometry perturbations. Localized activation simulated by the 76-dipole source cannot be detected in either the 20- or the 9-dipole solutions, even in the absence of noise and perturbations. Solutions calculated from potentials measured in vivo yield results that are unphysiologic. 相似文献
73.
Manschreck Theo C.; Maher Brendan A.; Rucklos Mary E.; Veneer Donald R. Jr.; Ader Deborah N. 《Canadian Metallurgical Quarterly》1981,90(4):321
Introduced a laboratory measure of motor function, synchronization of tapping with an auditory stimulus, as an index of motor disorganization in schizophrenia. It was hypothesized that (a) schizophrenics' performance on this task would be distinguishable from that of controls and would reflect a relative inability to take advantage of stimulus predictability, independent of task difficulty; (b) clinical measures of disturbed motor behavior would be associated with poorer synchronization; and (c) synchronization performance would be associated with clinical ratings of formal thought disorder and type-token ratio assessment of disorganization in spoken language. 16 schizophrenic, 8 affective, and 8 normal controls (18–48 yrs) were studied. The schizophrenics showed a specific pattern of disrupted synchrony not consistent with explanations based on S motivation, task difficulty, motor dexterity, a general psychosis factor, drug effects, or tapping speed ability. Deficient motor performance was associated with clinical evidence of abnormal movement and disturbed thinking and with the type-token ratio. (44 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
74.
ErikW. van Hellemond Linda Vermote Wilma Koolen Theo Sonke Ellen Zandvoort Dominic P.H.M. Heuts DickB. Janssen MarcoW. Fraaije 《Advanced Synthesis \u0026amp; Catalysis》2009,351(10):1523-1530
The substrate scope of the flavoprotein alditol oxidase (AldO) from Streptomyces coelicolor A3(2), recombinantly produced in Escherichia coli, was explored. While it has been established that AldO efficiently oxidizes alditols to D ‐aldoses, this study revealed that the enzyme is also active with a broad range of aliphatic and aromatic alcohols. Alcohols containing hydroxy groups at the C‐1 and C‐2 positions like 1,2,4‐butanetriol (Km=170 mM, kcat=4.4 s−1), 1,2‐pentanediol (Km=52 mM, kcat=0.85 s−1) and 1,2‐hexanediol (Km=97 mM, kcat=2.0 s−1) were readily accepted by AldO. Furthermore, the enzyme was highly enantioselective for the oxidation of 1,2‐diols [e.g., for 1‐phenyl‐1,2‐ethanediol the (R)‐enantiomer was preferred with an E‐value of 74]. For several diols the oxidation products were determined by GC‐MS and NMR. Interestingly, for all tested 1,2‐diols the products were found to be the α‐hydroxy acids instead of the expected α‐hydroxy aldehydes. Incubation of (R)‐1‐phenyl‐1,2‐ethanediol with 18O‐labelled water (H218O) revealed that a second enzymatic oxidation step occurs via the hydrate product intermediate. The relaxed substrate specificity, excellent enantioselectivity, and independence of coenzymes make AldO an attractive enzyme for the preparation of optically pure 1,2‐diols and α‐hydroxy acids. 相似文献
75.
Costs of mastitis: facts and perception 总被引:2,自引:0,他引:2
A model to calculate the economic losses of mastitis on an average Dutch dairy farm was developed and used as base for a tool for farmers and advisors to calculate farm-specific economic losses of mastitis. The economic losses of a clinical case in a default situation were calculated as euro210, varying from euro164 to euro235 depending on the month of lactation. The total economic losses of mastitis (subclinical and clinical) per cow present in a default situation varied between euro65 and euro182/cow per year depending on the bulk tank somatic cell count. The tool was used to measure perception of the total economic losses of mastitis on the farm and the farmers' assessment of the cost factors of mastitis on 78 dairy farms, of which 64 were used for further analyses. Most farmers (72%) expected their economic losses to be lower than those revealed by our calculation made with their farm information. Underestimating the economic losses of mastitis can be regarded as a general problem in the dairy sector. The average economic losses assessed by the farmers were euro78/cow per year, but a large variation was given, euro17-198/cow per year. Although the average assessment of the farmers of the different cost factors is close to the default value, there is much variation. To improve the adoption rate of advice and lower the incidence of mastitis, it is important to show the farmers the economic losses of mastitis on their farm. The tool described in this paper can play a role in that process. 相似文献
76.
André Scholz Argang Ghadiri Usha Singh Johannes Wendsche Theo Peters Stefan Schneider 《Ergonomics》2018,61(2):255-264
Work breaks are known to have positive effects on employees’ health, performance and safety. Using a sample of twelve employees working in a stressful and cognitively demanding working environment, this experimental field study examined how different types of work breaks (boxing, deep relaxation and usual breaks) affect participants’ mood, cognitive performance and neurophysiological state compared to a control condition without any break. In a repeated measures experimental design, cognitive performance was assessed using an auditory oddball test and a Movement Detection Test. Brain cortical activity was recorded using electroencephalography. Individual’s mood was analysed using a profile of mood state. Although neurophysiological data showed improved relaxation of cortical state after boxing (vs. ‘no break’ and ‘deep relaxation’), neither performance nor mood assessment showed similar results. It remains questionable whether there is a universal work break type that has beneficial effects for all individuals.
Practitioner Summary: Research on work breaks and their positive effects on employees’ health and performance often disregards break activities. This experimental field study in a stressful working environment investigated the effect of different work break activities. A universal work break type that is beneficial for this workplace could not be identified. 相似文献
77.
Afrasiabi Mahlagha Khotanlou Hassan Gevers Theo 《Multimedia Tools and Applications》2020,79(27-28):20019-20038
Multimedia Tools and Applications - Predicting the interaction between two humans, when viewed as a part of video is one of the most challenging issues in the field of computer vision, due to its... 相似文献
78.
Fares Alnajar Theo Gevers Roberto Valenti Sennay Ghebreab 《International Journal of Computer Vision》2017,124(2):223-236
We present a novel method to auto-calibrate gaze estimators based on gaze patterns obtained from other viewers. Our method is based on the observation that the gaze patterns of humans are indicative of where a new viewer will look at. When a new viewer is looking at a stimulus, we first estimate a topology of gaze points (initial gaze points). Next, these points are transformed so that they match the gaze patterns of other humans to find the correct gaze points. In a flexible uncalibrated setup with a web camera and no chin rest, the proposed method is tested on ten subjects and ten images. The method estimates the gaze points after looking at a stimulus for a few seconds with an average error below \(4.5^{\circ }\). Although the reported performance is lower than what could be achieved with dedicated hardware or calibrated setup, the proposed method still provides sufficient accuracy to trace the viewer attention. This is promising considering the fact that auto-calibration is done in a flexible setup , without the use of a chin rest, and based only on a few seconds of gaze initialization data. To the best of our knowledge, this is the first work to use human gaze patterns in order to auto-calibrate gaze estimators. 相似文献
79.
80.
Karl G. Schell Susanne Wagner Pascal Hettich Theo Fett Gabriele Rizzi Michael J. Hoffmann 《Journal of the American Ceramic Society》2017,100(9):4173-4179
Cracks terminating at free surfaces are affected by local stresses in the surface region. Under residual compression the crack front must retard compared with the crack contour in the absence of stresses. This effect can be used for an identification of residual stresses at glass surfaces. For an illustration of the procedure, Vickers indentation tests in soda‐lime glass are considered. Specimens treated by ion exchange and chemically toughening showed reduced terminating angles compared with untreated glass. 相似文献