918 research outputs found

    Die Lehre von der tonischen Innervation

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    De la inervaciĂł tĂČnica

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    Morphological Convergence in Forest Microfungi Provides a Proxy for Paleogene Forest Structure

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    Amber, fossilized plant resin from gymnosperms and angiosperms, is renowned for preserving a wide range of organisms in microscopic fidelity. These so-called amber inclusions comprise many groups of organisms, ranging from bacteria to arthropods and vertebrates. Calicioid lichens and fungi, which are from now on referred to as “calicioids,” constitute a diverse group of tiny ascomycetes with superficially similar, usually well-stalked ascomata and which often accumulate mature ascospores on top of the apothecial disk to form a true mazaedium. The aim of this study is to use all available information on the morphology and ecology of extant calicioids to reconstruct the substrate and habitat ecology of known fossil calicioids and then to use this information to open new insights into the stand structure and ecological conditions of European Paleogene amber forests. First, we introduce the morphology of extant calicioids and demonstrate that their structural features are intimately linked to habitat ecology and are instrumental for successful dispersal; we also explain the conspicuous morphological convergence between phylogenetically distant calicioid fungi. Then, we show that the adaptive traits of calicioids have not changed since at least the Eocene, and argue that their fundamental niches also have remained unchanged. Finally, we summarize what the diversity and relative abundance of fossil calicioids in amber tells us about the ecological conditions that once prevailed in European amber forests.Peer reviewe

    Digital LED Pixels: Instructions for use and a characterization of their properties

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    This article details how to control light emitting diodes (LEDs) using an ordinary desktop computer. By combining digitally addressable LEDs with an off-the-shelf microcontroller (Arduino), multiple LEDs can be controlled independently and with a high degree of temporal, chromatic, and luminance precision. The proposed solution is safe (can be powered by a 5-V battery), tested (has been used in published research), inexpensive (∌ 60+60 + 2 per LED), highly interoperable (can be controlled by any type of computer/operating system via a USB or Bluetooth connection), requires no prior knowledge of electrical engineering (components simply require plugging together), and uses widely available components for which established help forums already exist. Matlab code is provided, including a ‘minimal working example’ of use suitable for use by beginners. Properties of the recommended LEDs are also characterized, including their response time, luminance profile, and color gamut. Based on these, it is shown that the LEDs are highly stable in terms of both luminance and chromaticity, and do not suffer from issues of warm-up, chromatic shift, and slow response times associated with traditional CRT and LCD monitor technology

    Genetics and Plant Development

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    There are only three grand theories in biology: the theory of the cell, the theory of the gene, and the theory of evolution. Two of these, the cell and gene theories, originated in the study of plants, with the third resulting in part from botanical considerations as well. Mendel's elucidation of the rules of inheritance was a result of his experiments on peas. The rediscovery of Mendel's work in 1900 was by the botanists de Vries, Correns, and Tschermak. It was only in subsequent years that animals were also shown to have segregation of genetic elements in the exact same manner as had been shown in plants. The story of developmental biology is different – while the development of plants has long been studied, the experimental and genetic approaches to developmental mechanism were developed via experiments on animals, and the importance of genes in development (e.g., Waddington, 1940) and their use for understanding developmental mechanisms came to botanical science much later – as late as the 1980s
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