362 research outputs found

    Spontaneous rhythm discrimination in a mammalian vocal learner

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    Rhythm and vocal production learning are building blocks of human music and speech. Vocal learning has been hypothesized as a prerequisite for rhythmic capacities. Yet, no mammalian vocal learner but humans have shown the capacity to flexibly and spontaneously discriminate rhythmic patterns. Here we tested untrained rhythm discrimination in a mammalian vocal learning species, the harbour seal (Phoca vitulina). Twenty wild-born seals were exposed to music-like playbacks of conspecific call sequences varying in basic rhythmic properties. These properties were called length, sequence regularity, and overall tempo. All three features significantly influenced seals' reaction (number of looks and their duration), demonstrating spontaneous rhythm discrimination in a vocal learning mammal. This finding supports the rhythm–vocal learning hypothesis and showcases pinnipeds as promising models for comparative research on rhythmic phylogenies

    Extending the Breakthrough Listen nearby star survey to other stellar objects in the field

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    We extend the source sample recently observed by the Breakthrough Listen Initiative by including additional stars (with parallaxes measured by Gaia) that also reside within the FWHM of the GBT and Parkes radio telescope target fields. These stars have estimated distances as listed in the extensions of the Gaia DR2 catalogue. Enlarging the sample from 1327 to 288315 stellar objects permits us to achieve substantially better Continuous Waveform Transmitter Rate Figures of Merit (CWTFM) than any previous analysis, and allows us to place the tightest limits yet on the prevalence of nearby high-duty-cycle extraterrestrial transmitters. The results suggest 0.06600.0003+0.0004\lesssim 0.0660^{+0.0004}_{-0.0003}% of stellar systems within 50 pc host such transmitters (assuming an EIRP 1013 \gtrsim 10^{13} W) and 0.0390.008+0.004\lesssim 0.039^{+0.004}_{-0.008}% within 200 pc (assuming an EIRP 2.5×1014\gtrsim 2.5 \times 10^{14} W). We further extend our analysis to much greater distances, though we caution that the detection of narrow-band signals beyond a few hundred pc may be affected by interstellar scintillation. The extended sample also permits us to place new constraints on the prevalence of extraterrestrial transmitters by stellar type and spectral class. Our results suggest targeted analyses of SETI radio data can benefit from taking into account the fact that in addition to the target at the field centre, many other cosmic objects reside within the primary beam response of a parabolic radio telescope. These include foreground and background galactic stars, but also extragalactic systems. With distances measured by Gaia, these additional sources can be used to place improved limits on the prevalence of extraterrestrial transmitters, and extend the analysis to a wide range of cosmic objects.Comment: 10 pages, 5 figures, 3 tables. Accepted by MNRA

    A hydrodynamically optimized nano-electrospray ionization source and vacuum interface

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    The coupling of atmospheric pressure ionization (API) sources like electrospray ionization (ESI) to vacuum based applications like mass spectrometry (MS) or ion beam deposition (IBD) is done by differential pumping, starting with a capillary or pinhole inlet. Because of its low ion transfer efficiency the inlet represents a major bottleneck for these applications. Here we present a nano-ESI vacuum interface optimized to exploit the hydrodynamic drag of the background gas for collimation and the reduction of space charge repulsion. Up to a space charge limit of 40 nA we observe 100% current transmission through a capillary with an inlet and show by MS and IBD experiments that the transmitted ion beams are well defined and free of additional contamination compared to a conventional interface. Based on computational fluid dynamics modelling and ion transport simulations, we show how the specific shape enhances the collimation of the ion cloud. Mass selected ion currents in the nanoampere range available further downstream in high vacuum open many perspectives for the efficient use of electrospray ion beam deposition (ES-IBD) as a surface coating method

    A new species of Bungona in Turkey (Ephemeroptera, Baetidae): an unexpected biogeographic pattern within a pantropical complex of mayflies

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    By using an integrative approach, we describe a new species of mayfly, Bungona (Chopralla) pontica sp. n., from Turkey. The discovery of a representative of the tropical mayfly genus Bungona in the Middle East is rather unexpected. The new species shows all the main morphological characters of the subgenus Chopralla, which has its closest related species occurring in southeastern Asia. Barcoding clearly indicated that the new species represents an independent lineage isolated for a very long time from other members of the complex. The claw is equipped with two rows of three or four flattened denticles. This condition is a unique feature of Bungona (Chopralla) pontica sp. n. among West Palaearctic mayfly species. Within the subgenus Chopralla, the species can be identified by the presence of a simple, not bifid right prostheca (also present only in Bungona (Chopralla) liebenauae (Soldan, Braasch & Muu, 1987)), the shape of the labial palp, and the absence of protuberances on pronotum

    Causality and the semantics of provenance

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    Provenance, or information about the sources, derivation, custody or history of data, has been studied recently in a number of contexts, including databases, scientific workflows and the Semantic Web. Many provenance mechanisms have been developed, motivated by informal notions such as influence, dependence, explanation and causality. However, there has been little study of whether these mechanisms formally satisfy appropriate policies or even how to formalize relevant motivating concepts such as causality. We contend that mathematical models of these concepts are needed to justify and compare provenance techniques. In this paper we review a theory of causality based on structural models that has been developed in artificial intelligence, and describe work in progress on a causal semantics for provenance graphs.Comment: Workshop submissio

    A Formal Approach to Support Interoperability in Scientific Meta-workflows

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    Scientific workflows orchestrate the execution of complex experiments frequently using distributed computing platforms. Meta-workflows represent an emerging type of such workflows which aim to reuse existing workflows from potentially different workflow systems to achieve more complex and experimentation minimizing workflow design and testing efforts. Workflow interoperability plays a profound role in achieving this objective. This paper is focused at fostering interoperability across meta-workflows that combine workflows of different workflow systems from diverse scientific domains. This is achieved by formalizing definitions of meta-workflow and its different types to standardize their data structures used to describe workflows to be published and shared via public repositories. The paper also includes thorough formalization of two workflow interoperability approaches based on this formal description: the coarse-grained and fine-grained workflow interoperability approach. The paper presents a case study from Astrophysics which successfully demonstrates the use of the concepts of meta-workflows and workflow interoperability within a scientific simulation platform

    In Vitro Cultures of Schisandra chinensis (Turcz.) Baill. (Chinese Magnolia Vine)—a Potential Biotechnological Rich Source of Therapeutically Important Phenolic Acids

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    The contents of free phenolic acids and cinnamic acid were determined using an HPLC method in methanolic extracts from biomass of Schisandra chinensis (Turcz.) Baill. (Chinese magnolia vine) at different stages of organogenesis, cultured in vitro on a few variants of Murashige and Skoog (MS) medium, containing different concentrations of plant growth regulators 6-benzylaminopurine (BAP) and 1-naphthaleneacetic acid (NAA) (from 0.1 to 3.0 mg/l) and in extracts from overground parts of plants growing in vivo. Six of 12 analysed compounds were detected in all extracts: chlorogenic, p-coumaric, p-hydroxybenzoic, protocatechuic, salicylic and syringic acids. Total contents of the examined metabolites in biomass of shoot-differentiating callus culture cultivated on six MS medium variants were dependent on concentrations of growth regulators in the media and ranged from 14.90 to 60.05 mg/100 g d.w. Total contents of the compounds in biomass extracts from undifferentiating callus culture maintained only on two of six MS medium variants were higher and amounted to 74.54 and 78.24 mg/100 g d.w. Maximum total contents of phenolic acids in both types of in vitro cultures were greater than in fruits (55.73 mg/100 g d.w.) and leaves (4.55 mg/100 g d.w.) of plants gowning in vivo. Chlorogenic acid and salicylic acid were the main compounds identified in biomass extracts of shoot-differentiating callus cultures (max 22.60 and 21.17 mg/100 g d.w., respectively), while chlorogenic acid (max 38.43 mg/100 g d.w.) and protocatechuic acid (max 20.95 mg/100 g d.w.) prevailed in the extracts from undifferentiating callus cultures. Other compounds dominated in fruits, namely p-coumaric acid (23.36 mg/100 g d.w.) and syringic acid (14.96 mg/100 g d.w.). This is the first report on biochemical potential of cells from S. chinensis in vitro cultures to produce the biologically active phenolic acids. These are the first results on the analysis of this group of metabolites in overground parts of plants growing in vivo, too

    An earth-abundant Ni-based single-atom catalyst for selective photodegradation of pollutants

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    Highly efficient catalytic technologies are urgently needed to remove pharmaceutical pollutants from water. In this work, the preparation, characterization, and photocatalytic performance of an earth-abundant Ni-based heterogeneous catalyst featuring highly dispersed Ni species over nanosheets of carbon nitride are reported. The absence of any metallic nickel phase has been confirmed by spectrometric analyses, unveiling the Ni-N environment for the metal centers and attaining synergistic interfacial carrier transfer via N-Ni-N coordination. By combining advanced characterizations with kinetic investigations, it is demonstrated that these newly formed isolated single atoms of Ni act as a bridge, facilitating faster electron transfer, increasing the charge density on Ni, and reducing the photocarrier transfer barrier. Compared to literature precedents, this substantially enhances the degradation of gemfibrozil, a model pharmaceutical pollutant found in wastewater, reducing the formation of toxic benzenic byproducts during photooxidation. This effect, which is not observed over conventional nanoparticle-based materials, discriminates the role of single-atom and nanoparticle-based catalysis during degradation of pollutants. This work opens new avenues in designing selective and earth-abundant photocatalysts for advanced oxidation processes, showing the importance of atom coordination to control the surface and catalytic properties of single-atom materials.Web of Science57art. no. 210017
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