69 research outputs found

    Testing the robustness of laws of polysemy and brevity versus frequency

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    The pioneering research of G.K. Zipf on the relationship between word frequency and other word features led to the formulation of various linguistic laws. Here we focus on a couple of them: the meaning-frequency law, i.e. the tendency of more frequent words to be more polysemous, and the law of abbreviation, i.e. the tendency of more frequent words to be shorter. Here we evaluate the robustness of these laws in contexts where they have not been explored yet to our knowledge. The recovery of the laws again in new conditions provides support for the hypothesis that they originate from abstract mechanisms.Peer ReviewedPostprint (author's final draft

    Pupil Size in Spider Eyes Is Linked to Post-Ecdysal Lens Growth

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    In this study we describe a distinctive pigment ring that appears in spider eyes after ecdysis and successively decreases in size in the days thereafter. Although pigment stops in spider eyes are well known, size variability is, to our knowledge, reported here for the first time. Representative species from three families (Ctenidae, Sparassidae and Lycosidae) are investigated and, for one of these species (Cupiennius salei, Ctenidae), the progressive increase in pupil diameter is monitored. In this species the pupil occupies only a fourth of the total projected lens surface after ecdysis and reaches its final size after approximately ten days. MicroCT images suggest that the decrease of the pigment ring is linked to the growth of the corneal lens after ecdysis. The pigment rings might improve vision in the immature eye by shielding light rays that would otherwise enter the eye via peripheral regions of the cornea, beside the growing crystalline lens

    Software for the frontiers of quantum chemistry:An overview of developments in the Q-Chem 5 package

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    This article summarizes technical advances contained in the fifth major release of the Q-Chem quantum chemistry program package, covering developments since 2015. A comprehensive library of exchange–correlation functionals, along with a suite of correlated many-body methods, continues to be a hallmark of the Q-Chem software. The many-body methods include novel variants of both coupled-cluster and configuration-interaction approaches along with methods based on the algebraic diagrammatic construction and variational reduced density-matrix methods. Methods highlighted in Q-Chem 5 include a suite of tools for modeling core-level spectroscopy, methods for describing metastable resonances, methods for computing vibronic spectra, the nuclear–electronic orbital method, and several different energy decomposition analysis techniques. High-performance capabilities including multithreaded parallelism and support for calculations on graphics processing units are described. Q-Chem boasts a community of well over 100 active academic developers, and the continuing evolution of the software is supported by an “open teamware” model and an increasingly modular design

    25th annual computational neuroscience meeting: CNS-2016

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    The same neuron may play different functional roles in the neural circuits to which it belongs. For example, neurons in the Tritonia pedal ganglia may participate in variable phases of the swim motor rhythms [1]. While such neuronal functional variability is likely to play a major role the delivery of the functionality of neural systems, it is difficult to study it in most nervous systems. We work on the pyloric rhythm network of the crustacean stomatogastric ganglion (STG) [2]. Typically network models of the STG treat neurons of the same functional type as a single model neuron (e.g. PD neurons), assuming the same conductance parameters for these neurons and implying their synchronous firing [3, 4]. However, simultaneous recording of PD neurons shows differences between the timings of spikes of these neurons. This may indicate functional variability of these neurons. Here we modelled separately the two PD neurons of the STG in a multi-neuron model of the pyloric network. Our neuron models comply with known correlations between conductance parameters of ionic currents. Our results reproduce the experimental finding of increasing spike time distance between spikes originating from the two model PD neurons during their synchronised burst phase. The PD neuron with the larger calcium conductance generates its spikes before the other PD neuron. Larger potassium conductance values in the follower neuron imply longer delays between spikes, see Fig. 17.Neuromodulators change the conductance parameters of neurons and maintain the ratios of these parameters [5]. Our results show that such changes may shift the individual contribution of two PD neurons to the PD-phase of the pyloric rhythm altering their functionality within this rhythm. Our work paves the way towards an accessible experimental and computational framework for the analysis of the mechanisms and impact of functional variability of neurons within the neural circuits to which they belong

    Dispersion of the bio-aerosol produced by the oak processionary moth

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    The oak processionary moth (Thaumetopoea processionea L.) is found in oak forests in most European countries. The caterpillars bear urticating hairs (setae) as a chemical defence. These hairs break off and are small enough to become airborne and be transported by the wind. Upon contact with humans the toxin can cause an allergic reaction that ranges from a skin rash to respiratory distress. In order to measure the terminal settling velocity of this bioaerosol, we used a small elutriator and tested its functionality with particles of known aerodynamic diameter. We determined that the mean settling velocity of the setae is about 1 cm/s, corresponding to an aerodynamic diameter of 19 mu m for setae with a diameter of 6 mu m and a length of 190 mu m. The dispersion of the hairs in the atmosphere for a typical summer day was calculated by means of an Eulerian model. The results of this calculation revealed that the maximum concentrations in the atmosphere on a typical summer day reach 20-30% of the concentration found directly at the source. Those maximum concentrations are reached at a distance from the source that varies between 174 and 562 m, depending on the atmospheric stability and the settling velocity

    Schadstoffarme Prozesse in Galvanotechnik und Metallchemie. Teilvorhaben 7: Entwicklung und Erprobung einer Prozesstechnik zur Regenerierung galvanischer Elektrolyte - Industrierahmen Schlussbericht

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    The service life of galvanic electrolytes is limited by the concentration of organic foreign substances. The removal of such substances is currently associated with high losses of matter and waste water pollution, a method of process control which produces a low quantity of waste products is not possible therefore. By using regenerative adsorber polymers, these interfering substances are to be removed from the galvanizing electrolytes without causing any considerable losses. With a method of process control which is low in waste products and free of waste water, a practically unlimited service life of the electrolytes is thus achieved. The method was tested on nickel electrolytes under practical conditions. In the process, it was proven that an extensive, selective removal of organic foreign substances is possible. The adsorption capacities attainable are dependent upon the feed concentration. For designing plants, selecting the adsorber polymers and deciding on the regenerating technology, it is essential that aptitude tests be carried out on the electrolytes to be regenerated. The regeneration of the polymers was carried out by means of purely inorganic chemicals in two stages: anoxydizing with H_2O_2 or S_2O_8 and regenerating with NaOH. The multiple utilization of the regenerants was able to be proven, dependent upon the electrolytes. The tests led to the development of a plant prototype in four stages of performance. The adsorption method provides a regenerator which enables the material cycle to be closed in the case of process solutions containing organics. Applying the method to other process solutions containing organics (e.g. the cleaning of waste hydrochloric acid) is conceivable. (orig.)SIGLEAvailable from TIB Hannover: F97B1020+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

    Some parallels between language and music from a cognitive and evolutionary perspective

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          Parallels between language and music are considered as a useful basis for examining possible evolutionary pathways of these achievements. Such parallels become apparent if we compare clauses and syllables in language with phrases and notes in music: Clauses as well as musical phrases typically span about 2 sec and about 5 to 10 pulses, i.e., syllables or notes. The n of syllables per clause or intonation unit also can be used as a measure of tempo across languages and thus also as a means for a better understanding of typological co-variations in the rhythm of speech and music. Further correspondences were found between the size of the sound-relevant inventories, i.e., vowels and musical intervals: a minimum of roughly 3 and a maximum of roughly 12 elements as well as a frequency peak at 5 elements. A link between vowels and musical intervals is also indicated by our findings that in Alpine yodellers the vowels are highly correlated to melodic direction according to their F2 ordering. These parallels are discussed from an evolutionary perspective that either sees music as a precursor of language or both language and music as descendents of a common, half-musical precursor (Jespersen, 1895; Brown, 2000). A rather simple explanation of the parallels is reported: If singing in a broader sense of the word is the most original form of music, then the functionality of any mechanism involved in the programming and the online-control of intonation units will be reflected in language as well as in music
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