Border Collision Bifurcations in a Footloose Capital Model with First Nature Firms

In this paper we extend the discrete time Footloose Capital model analyzed in Commendatore et al. (Nonlinear Dyn Psychol Life Sci 11(2):267–289, 2007) by introducing “first nature firms”, i.e., firms that use locally specific blueprints and, therefore, are immobile. Due to the presence of first nature firms (symmetrically distributed across the regions), the central dynamic map becomes a piecewise differentiable function: in addition to “standard” flip and pitchfork bifurcations also border collision bifurcations are possible and instances of multistability may emerge. Our analysis confirms and extends the results of Commendatore et al. (2007): (1) continuous time formulation hides complex dynamics patterns; (2) asymmetric distributions of industrial activity can be endogenously generated and are path dependent.     

Studies on the germination specific α-amylase and its inhibitor of rye (Secale cereale) 3. Estimation of a-amylase inhibitor activity

Summary A method is presented for estimating the -amylase II inhibitor activity in rye and isolated preparations (inhibition of germination-specific -amylase II from germinated rye). It was established that the residual activity of -amylase activity did not decrease linearly but was retarded in dependence on the inhibitor concentration. A plot of the reciprocal of the-amylase II residual activity in dependence on the inhibitor/-amylase II mass ratio showed linearity up to 50% residual activity. From this, an estimation method has been derived. Further, a computer program has been developed to calculate the results. Finally a simplified procedure (two-point method) is proposed in order to rationalize the application. The formation of the enzyme-inhibitor complex is complete after 10 min at 35° C and a preincubation time of no more than 15 min is needed before determining the inhibitor activity. The method has been found to be convenient for the inhibitor analysis of the cereal grain, flour and purified fractions and the characterization of the -amylase II inhibitor.

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Untersuchungen zur keimungsspezifischen -Amylase und deren Inhibitor im Roggen (Secale cereale) 3. Bestimmung der -Amylase-Inhibitor-Aktivität

Zusammenfassung Es wird eine Methode zur Bestimmung der -Amylase-II-Inhibitor-Aktivität in Roggen sowie daraus isolierten Präparaten (Hemmung der keimungsspezifischen -Amylase-II aus gekeimtem Roggen) vorgestellt. Bei den Untersuchungen wird festgestellt, daß die -Amylase-II-Restaktivität mit steigendem Inhibitorzusatz nicht linear, sondern von Anfang an verzögert abnimmt. Bei reziproker Darstellung der -Amylase-II-Restaktivität gegen das Inhibitor--Amylase-II-Verhältnis besteht bis etwa 50% Restaktivität Linearität. Hieraus wird ein Bestimmungsverfahren abgeleitet. Die Berechnung erfolgt über ein speziell entwickeltes Computerprogramm. Ferner wird ein vereinfachtes Verfahren (Zwei-Punkt-Methode) vorgeschlagen, um seine Anwendung zu rationalisieren. Die Ausbildung eines stabilen Enzym-Inhibitor-Komplexes ist bei 35 °C bereits nach 10 min abgeschlossen, so daß vor der Bestimmung der Inhibitor-Aktivität eine Präinkubationszeit von 15 min ausreicht. Das Verfahren hat sich bei Untersuchungen zur Reinigung und Charakterisierung von -Amylase-II-Inhibitoren aus Roggen bewährt (vgl. 2. Mitt.).

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Explanation of symbols used for calculation A -amylase II activity (U/g) without inhibitor addition;A=1/Y - A(I) -amylase II activity in the presence of inhibitor (U/g);A (I)=O(I)·F·D/(C·t·0.1) - AI -amylase II inhibitor activity (IU/g);AI=0.5·A/X - B regression coefficient [(g amylase/U)/(g inhibitor/g amylase];B=Y/X - C -amylase II mass (g) - D -amylase II dilution (ml); volume to whichC was diluted - E -amylase II in test volume (g/0.1 ml);E=C·0.1/D - F factor for calculating maltose equivalents from the calibration curve (mol maltose) - I designation of measured values (no.) - IU inhibitor unit - J(I) inhibitor mass (g) - K(I) inhibitor dilution (ml); volume to whichJ (I) was diluted - L(I) inhibitor in test volume (g/0.1 ml);L(I)=J(I)·0.1/K(I) - N number of measured values - O(I) absorbance at 530 nm in 1-cm cell - P(I) -amylase II activity (%), relative toA(I)=-amylase II activity without inhibitor addition=100%;P(I)=A (I)·100/A(I) - R correlation coefficient - t incubation time (min); t=15 min - U -amylase II activity unit - X inhibitor/-amylase II mass ratio at 50% residual activity;X=Y/B - X(I) inhibitor/-amylase II mass ratio;X(I)=L(I)/E - Y reciprocal -amylase II activity (g/U) without inhibitor addition, calculated from the regression equation;Y(I)=Y+B·X(I);Y=1/A - Y(I) reciprocal -amylase II activity;Y (I)=1/A(I)=C·t·0.1/[O(I)·F·D]     

Beitrag zur Unterscheidung von G?rungsessig und synthetischem S?ureessig durch die massenspektrometrische Bestimmung des13C/12-Isotopenverh?ltnisses

Zusammenfassung Das¹³C/¹²C-Isotopenverhältnis wurde als Unterscheidungsmerkmal zwischen synthetischem und biogenem Essig herangezogen. Die Essigsäure wurde als Calciumacetat aus dem Essig isoliert, das Calciumacetat zu CaCO₃ pyrolysiert und daraus mit H₃PO₄ das CO₂ freigesetzt. Die Messung des CO₂ erfolgte in einem Massenspektrometer mit Doppelkollektor. Der Unterschied im¹³C-Gehalt der beiden Essigarten beträgt etwa 5, die Meßgenauigkeit liegt bei 0,5- 1. Daher können auch Verschnitte ab einem Gehalt von 15–20% an synthetischer Essigsäure in biogenem Essig als solche identifiziert werden.

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A method for differentiating between vinegar produced by fermentation and vinegar made from synthetic acetic acid based on determination of the¹³C/¹²C-isotope ratio by mass spectrometry

Summary The¹³C/¹²C-isotope ratio is characteristic for vinegar of fermentation and synthetic origin respectively and used for their differentiation. The acetic acid was isolated from the vinegar as calcium acetate, the calcium acetate was pyrolysed to CaCO₃ and the CO₂ was released from the CaCO₃ with H₃PO₄. The CO₂ was measured in a mass spectrometer with double collector. The difference in the¹³C-content between the two varieties of vinegar is 5; the accuracy of the measurement is between 0,5 and 1. Therefore, addition of synthetic acetic acid in excess of 15–20% to fermentation vinegar can be detected by this method.

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Wir danken dem Forschungsförderungsfonds der gewerblichen Wirtschaft und der Arbeitsgemeinschaft der Gärungsessigerzeuger Österreichs für die finanzielle Unterstützung dieser Arbeit Sonderdruckanfragen an: Dr. E. R. Schmid (Adresse siehe oben)     

A phase-cycled temperature-sensitive fast spin echo sequence with conductivity bias correction for monitoring of mild RF hyperthermia with PRFS

Magnetic Resonance Materials in Physics, Biology and Medicine - Mild hyperthermia (HT) treatments are generally monitored by phase-referenced proton resonance frequency shift calculations. A novel...     

Artificial Force Field for Haptic Feedback in UAV Teleoperation

The feedback upon which operators in teleoperation tasks base their control actions differs substantially from the feedback to the driver of a vehicle. On the one hand, there is often a lack of sensory information; on the other hand, there is additional status information presented via the visual channel. Haptic feedback could be used to unload the visual channel and to compensate for the lack of feedback in other modalities. For collision avoidance, haptic feedback could provide repulsive forces via the control inceptor. Haptic feedback allows operators to interpret the repulsive forces as impedance to their control deflections when a potential for collision exists. Haptic information can be generated from an artificial force field (AFF) that maps environment constraints to repulsive forces. This paper describes the design and theoretical evaluation of a novel AFF, i.e., the parametric risk field, for teleoperation of an uninhabited aerial vehicle (UAV). The field allows adjustments of the size, shape, and force gradient by means of parameter settings, which determine the sensitivity of the field. Computer simulations were conducted to evaluate the effectiveness of the field for collision avoidance for various parameter settings. Results indicate that the novel AFF more effectively performs the collision avoidance function than potential fields known from literature. Because of its smaller size, the field yields lower repulsive forces, results in less force cancellation effects, and allows for larger UAV velocities. This indicates less operator control demand and more effective UAV operations, both expected to lead to lower operator workload, while, at the same time, increasing safety.     

Measuring visual fatigue and visual discomfort associated with 3‐D displays

Abstract— This research identifies methods for signs of visual complaints associated with stereoscopic displays. Two potential causes for contradictory results concerning these signs in previous research are hypothesized: (1) not all clinical tests are equally appropriate and (2) there is a natural variation in susceptibility amongst people with normal vision. An optometric screening differentiated participants with moderate binocular status (MBS) from those with good binocular status (GBS). In a 2 × 2 within‐subjects design (2‐D vs. 3‐D and MBS vs. GBS), a questionnaire and eight optometric tests (i.e., binocular acuity, aligning prism, fixation disparity, heterophoria, convergent and divergent fusional reserves, vergence facility, and accommodation response) were each administered before and immediately after a reading task. Results revealed that only participants with MBS in 3‐D conditions showed clinically meaningful changes in fusion range, experienced more visual discomfort, and performed worse on the reading task. Acombination of fusion range measurements and self‐report is appropriate for evaluating visual complaints of stereoscopic stills, and people with a MBS are more susceptible to visual complaints associated with stereoscopic displays. A simple measurement tool, i.e., the ratio of reading performance between 2‐D and 3‐D, to categorize people based on their binocular status is proposed.     

Preferred and maximally acceptable color gamut for reproducing natural image content

Abstract— With the development of wide‐gamut display technology, the need is clear for understanding the required size and shape of color gamut from the viewers' perspective. To that end, experiments were conducted to explore color‐gamut requirements based on viewers' preferred level of chroma enhancement of standard‐gamut images. Chroma preferences were measured for multiple hues using single‐hue images, and a corresponding hue‐dependent preferred chroma enhancement was successfully applied to natural, multi‐hue images. The multi‐hue images showed overall success, though viewers indicated that reds could be decreased even further in colorfulness, and yellows could be increased, which may argue in favor of multi‐primary displays. Viewer preferences do vary within the population, primarily in overall chroma level, and the differences can be largely accounted for with a single parameter for chroma‐level adjustment that includes the preferred hue dependence. Image content dependencies were also found, but they remain too complex to model. The hue‐dependent chroma preference results can be applied to display design and color‐enhancement algorithms.     

Goodness-of-fit tests for the error distribution in nonparametric regression

Suppose the random vector (X,Y) satisfies the regression model Y=m(X)+σ(X)ε, where m(⋅) is the conditional mean, σ²(⋅) is the conditional variance, and ε is independent of X. The covariate X is d-dimensional (d≥1), the response Y is one-dimensional, and m and σ are unknown but smooth functions. Goodness-of-fit tests for the parametric form of the error distribution are studied under this model, without assuming any parametric form for m or σ. The proposed tests are based on the difference between a nonparametric estimator of the error distribution and an estimator obtained under the null hypothesis of a parametric model. The large sample properties of the proposed test statistics are obtained, as well as those of the estimator of the parameter vector under the null hypothesis. Finally, the finite sample behavior of the proposed statistics, and the selection of the bandwidths for estimating m and σ are extensively studied via simulations.     

Least squares estimation of nonlinear spatial trends

Results on asymptotic and finite sample properties of an estimator of a nonlinear regression function when errors are spatially correlated, and when the spatial dependence structure is unknown are derived. The proposed method is based on a generalized nonlinear least squares approach, taking into account the spatial covariance. Weak consistency of the regression parameters estimator is derived, along with its asymptotic Gaussian limit. The behavior of the proposed estimator is illustrated with a simulation study, considering different correlation structures in and a more general case including a spatial covariate. The method is also applied to two real data cases.     

Violations and errors during simulation-based driver training

The effectiveness of virtual driving instruction can increase when techniques that automatically distinguish between violations and errors are available, two behaviours requiring different types of remediation. This study reports the analysis of the objectively measured performance of 520 participants completing a simulation-based training programme. Factor analysis of failure reasons showed that violations and errors were the primary underlying factors. Men committed more violations and women made more errors; the magnitude of sex differences corresponded to the factor loadings. Factor analysis of the mean task completion times yielded a factor that can be described as the extent to which motivation for speed resulted in quicker task execution. Quicker participants completed more tasks, committed more violations, but made fewer errors. Participants reduced errors during forced-paced driving and increased speed during self-paced driving. The authors would recommend exploiting the distinction between violations and errors by developing interfaces and feedback for both types of aberration.