Allelopathic potential of menthofuran monoterpenes fromCalamintha ashei

A reversed-phase HPLC analysis was used to separate and quantify five menthofuran monoterpenes inCalamintha ashei leaf soaks and washes. (+)-Evodone and desacetylcalaminthone were the major constituents of both soaks and washes. Concentrations of (+)-evodone and desacetylcalaminthone were as high as 0.66 and 0.74 mM, respectively, in leaf soaks. The highest concentration of monoterpenes in leaf washes obtained by misting was 0.021 mM. Aqueous solubilities of the menthofurans were determined to exceed concentrations required for growth inhibition. Bioassays of individualCalamintha monoterpenes demonstrated effects on germination as low as 0.05 mM for (+)-evodone. An equimolar mixture of desacetylcalaminthone and (+)-evodone reducedRudbeckia hirta germination by 17% at a combined concentration of 0.025 mM forLeptochloa dubia. Confirmation of allelopathic effects byCalamintha ashei will require long-term bioassays ofCalamintha menthofurans on the growth of native sandhill species under conditions comparable to the harsh environment of the Florida scrub.     

Sterol and fatty acid composition of neutral lipids ofParatenuisentis ambiguus and its host eel

The sterol composition of free sterol and steryl ester fractions of the fish parasiteParatenuisentis ambiguus was determined. In addition, the fatty acid composition of various neutral lipid classes, i.e., wax esters, steryl esters, triacylglycerols and free fatty acids, as well as the composition of the 1-O-alkyl moieties of total ether glycerolipids of the parasite, were investigated. The results of these studies were compared with those obtained on the intestinal tract tissue of its host, the eel (Anguilla anguilla). Cholesterol is the major sterol in bothP. ambiguus andA. anguilla. However, the sterols ofP. ambiguus contain high proportions (>20%) of other sterols, such as campesterol and various dehydrosterols. [e.g., 7-dehydrocholesterol and cholesta-5,22(E)-dienol]. The presence of these minor sterols agrees with the known biotransformations of exogenous sterols in various helminths. Considerable differences are found in the fatty acid composition of neutral lipid fractions, as well as the total lipid extract from the endoparasite as compared to the host tissue. In particular, eicosapentaenoic acid (20∶5n−3), other polyunsaturated fatty acids, such as 20∶4n−6, 22∶5n−3 and 22∶6n−3, as well as long-chain saturated fatty acids, such as 20∶0, are generally enriched in the neutral lipid fractions of the parasite as compared to those of infected eel intestine. The analysis of ether glycerolipids revealed that 1-O-hexadecyl (16∶0) and 1-O-hexadecenyl (16∶1) moieties were present in similar proportions in the ether lipids of bothP. ambiguus and eel intestine, whereas 1-O-octadecyl (18∶0) moieties are more prominent in the parasite and 1-O-octadecenyl (18∶1) moieties in the eel. The results of these studies show thatP. ambiguus has specific mechanisms for the regulation of the sterol and fatty acid composition of its neutral lipids. Dedicated to Professor Helmut K. Mangold on the occasion of his 70th birthday.     

Robots assembling machines: learning from the World Robot Summit 2018 Assembly Challenge

ABSTRACT

The Industrial Assembly Challenge at the World Robot Summit was held in 2018 to showcase the state-of-the-art of autonomous manufacturing systems. The challenge included various tasks, such as bin picking, kitting, and assembly of standard industrial parts into 2D and 3D assemblies. Some of the tasks were only revealed at the competition itself, representing the challenge of ‘level 5’ automation, i.e. programming and setting up an autonomous assembly system in less than one day. We conducted a survey among the teams that participated in the challenge and investigated aspects such as team composition, development costs, system setups as well as the teams' strategies and approaches. An analysis of the survey results reveals that the competitors have been in two camps: those constructing conventional robotic work cells with off-the-shelf tools, and teams who mostly relied on custom-made end effectors and novel software approaches in combination with collaborative robots. While both camps performed reasonably well, the winning team chose a middle ground in between, combining the efficiency of established play-back programming with the autonomy gained by CAD-based object detection and force control for assembly operations.     

Analysis of heuristic validity,efficiency and applicability of the profile distance method for implementation in decision support systems

This article seeks to enhance acceptance of the profile distance method (PDM) in decision support systems. The PDM is a multiple attributive-based decision making as well as a multiple method approach to support complex decision making and uses a heuristic to avoid computationally complex global optimization. We elaborate on the usability of the method and question the heuristic used. We present a bi-section algorithm, which efficiently supports the discovery of transition profiles needed in a user-friendly and practical application of the method. Additionally, we provide empirical evidence showing that the proposed heuristic is efficient and delivers results within 5% of the global optimizer for a wide range of datasets.     

Principles of a brain-computer interface (BCI) based on real-time functional magnetic resonance imaging (fMRI)

A brain-computer interface (BCI) based on functional magnetic resonance imaging (fMRI) records noninvasively activity of the entire brain with a high spatial resolution. We present a fMRI-based BCI which performs data processing and feedback of the hemodynamic brain activity within 1.3 s. Using this technique, differential feedback and self-regulation is feasible as exemplified by the supplementary motor area (SMA) and parahippocampal place area (PPA). Technical and experimental aspects are discussed with respect to neurofeedback. The methodology now allows for studying behavioral effects and strategies of local self-regulation in healthy and diseased subjects.     

An ADL measure for spinal cord injury

Occupational therapists do not have a comprehensive, objective method for measuring how persons with tetraplegia perform activities of daily living (ADL) in their homes and communities, because SCI ADL performance is usually determined in rehabilitation. The ADL Habits Survey (ADLHS) is designed specifically to address this knowledge gap by surveying performance on relevant and meaningful activities in homes and communities. After a comprehensive task analysis and pilot development, 30 activities were selected that emphasize a broad range of hand and wrist, reaching, and grasping movements in compound activities. A sample of 49 persons with cervical spinal cord injuries responded to items. The sample was predominantly male, median age was 41 years, and ASIA motor classification levels ranged from C2 through C8/T1 with majority concentration in C4, C5, or C6 (68%). Each participant report was rated by an occupational therapist using a seven category rating scale, and the item by participant response matrix (30 X 49) was analyzed with a Rasch model for rating scales. Results showed excellent participant separation (>4) and very high reliability (>.95), and both item and participant fit values were adequate (STANDARDIZED INFIT less than absolute value of 3). With only two exceptions, all participants fit the Rasch rating scale model, and only one item "Light housekeeping" presented significant fit issues. Principal Components Analysis an analysis of item residuals did not reveal serious threats to unidimensionality. A between group fit comparison of participants with more versus less movement found invariant item calibrations, and ANOVA of participant measures found statistically significant differences across ASIA motor classification levels. These ADLHS results offer occupational therapists a new method for measuring ADL that is potentially more sensitive to functional changes in tetraplegia than most instruments in common use. Accommodation of step disorder with a three category rating scale did not diminish measurement properties.     

Log-Linear Convergence and Divergence of the Scale-Invariant (1+1)-ES in Noisy Environments

Noise is present in many real-world continuous optimization problems. Stochastic search algorithms such as Evolution Strategies (ESs) have been proposed as effective search methods in such contexts. In this paper, we provide a mathematical analysis of the convergence of a (1+1)-ES on unimodal spherical objective functions in the presence of noise. We prove for a multiplicative noise model that for a positive expected value of the noisy objective function, convergence or divergence happens depending on the infimum of the support of the noise. Moreover, we investigate convergence rates and show that log-linear convergence is preserved in presence of noise. This result is a strong theoretical foundation of the robustness of ESs with respect to noise.     

Drawing polytopal graphs with polymake

This note wants to explain how to obtain meaningful pictures of (possibly high-dimensional) convex polytopes, triangulated manifolds, and other objects from the realm of geometric combinatorics such as tight spans of finite metric spaces and tropical polytopes. In all our cases we arrive at specific, geometrically motivated, graph drawing problems. The methods displayed are implemented in the software system polymake.     

Learning probability distributions in continuous evolutionary algorithms – a comparative review

We present a comparative review of Evolutionary Algorithms that generate new population members by sampling a probability distributionconstructed during the optimization process. We present a unifying formulation for five such algorithms that enables us to characterize them based on the parametrization of the probability distribution, the learning methodology, and the use of historical information.The algorithms are evaluated on a number of test functions in order to assess their relative strengths and weaknesses. This comparative reviewhelps to identify areas of applicability for the algorithms and to guidefuture algorithmic developments.