470 research outputs found

    Sensitivity of Antarctic Urospora penicilliformis (Ulotrichales, Chlorophyta) to ultraviolet radiation is life stage dependent

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    The sensitivity of different life stages of the eulittoral green alga Urospora penicilliformis (Roth) Aresch. to ultraviolet radiation (UVR) was examinedin the laboratory. Gametophytic filaments and propagules (zoospores and gametes) released from filaments were separately exposed to different fluence of radiation treatments consisting of PAR (P = 400700 nm), PAR + ultraviolet A (UVA) (PA, UVA = 320400 nm), and PAR + UVA + ultraviolet B (UVB) (PAB, UVB = 280320 nm). Photophysiological indices (ETRmax, Ek, and a) derived from rapid light curves were measured in controls, while photosynthetic efficiency and amount of DNA lesions in terms of cyclobutane pyrimidine dimers (CPDs) were measured after exposure to radiation treatments and after recovery in low PAR; pigments of propagules were quantified after exposure treatment only. The photosynthetic conversion efficiency (a) and photosynthetic capacity (rETRmax) were higher in gametophytes compared with the propagules. The propagules were slightly more sensitive to UVB-induced DNA damage; however, both life stages of the eulittoral inhabiting turf alga were not severely affected by the negative impacts of UVR. Exposure to a maximum of 8 h UVR caused mild effects on the photochemical efficiency of PSII and induced minimal DNA lesions in both the gametophytes and propagules. Pigment concentrations were not significantly different between PAR-exposed and PAR + UVRexposed propagules. Our data showed that U. penicilliformis from the Antarctic is ratherinsensitive to the applied UVR. This amphi-equatorial species possesses different protective mechanisms that can cope with high UVR in coldtemperatewaters of both hemispheres and in polar regions under conditions of increasing UVR as a consequence of further reduction of stratosphericozone

    The in vivo transcriptome of Schistosoma mansoni in the prominent vector species Biomphalaria pfeifferi with supporting observations from Biomphalaria glabrata.

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    BackgroundThe full scope of the genes expressed by schistosomes during intramolluscan development has yet to be characterized. Understanding the gene products deployed by larval schistosomes in their snail hosts will provide insights into their establishment, maintenance, asexual reproduction, ability to castrate their hosts, and their prolific production of human-infective cercariae. Using the Illumina platform, the intramolluscan transcriptome of Schistosoma mansoni was investigated in field-derived specimens of the prominent vector species Biomphalaria pfeifferi at 1 and 3 days post infection (d) and from snails shedding cercariae. These S. mansoni samples were derived from the same snails used in our complementary B. pfeifferi transcriptomic study. We supplemented this view with microarray analyses of S. mansoni from B. glabrata at 2d, 4d, 8d, 16d, and 32d to highlight robust features of S. mansoni transcription, even when a different technique and vector species was used.Principal findingsTranscripts representing at least 7,740 (66%) of known S. mansoni genes were expressed during intramolluscan development, with the greatest number expressed in snails shedding cercariae. Many transcripts were constitutively expressed throughout development featuring membrane transporters, and metabolic enzymes involved in protein and nucleic acid synthesis and cell division. Several proteases and protease inhibitors were expressed at all stages, including some proteases usually associated with cercariae. Transcripts associated with G-protein coupled receptors, germ cell perpetuation, and stress responses and defense were well represented. We noted transcripts homologous to planarian anti-bacterial factors, several neural development or neuropeptide transcripts including neuropeptide Y, and receptors that may be associated with schistosome germinal cell maintenance that could also impact host reproduction. In at least one snail the presence of larvae of another digenean species (an amphistome) was associated with repressed S. mansoni transcriptional activity.Conclusions/significanceThis in vivo study, emphasizing field-derived snails and schistosomes, but supplemented with observations from a lab model, provides a distinct view from previous studies of development of cultured intramolluscan stages from lab-maintained organisms. We found many highly represented transcripts with suspected or unknown functions, with connection to intramolluscan development yet to be elucidated

    Business Models for Internet of Things Platforms: Empirical Development of a Taxonomy and Archetypes

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    A wide range of Internet of Things platform providers operate diverse business models to cater for the manifold requirements of the IoT. This paper contributes to a more precise understanding of IoT platforms as an essential building block of the IoT based on the characteristics of its business models. Even though research listing technological dimensions according to which IoT platforms differ, they have neither been systematically derived nor been linked to the business model concept. In turn, they lack descriptive power on the heterogeneous value creation mechanisms of the platform providers. Within our research, we first analyzed 195 IoT platforms and systemically developed a taxonomy allowing the characterization of IoT platform business models. Second, based on this taxonomy, we identified nine archetypes of IoT platform business models and illustrated typical combinations of business model characteristics. Equipped with such an understanding, practice and research can analyze existing IoT platforms more accurately

    Digital M&A, digital innovation, and firm performance:an empirical investigation

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    Aiming to support digital innovation endeavours, industrial-age companies increasingly acquire firms that heavily build upon digital technologies. Related research has raised serious concerns regarding the prospects of such plans, yet has not focused the particular context of digital mergers and acquisitions (M&A). Drawing on a knowledge-based perspective as well as the particularities of digital technologies and the context of digital innovation, we theorise the link between digital M&A, a digital knowledge base on the part of the acquirer, and the consequences for digital innovation and firm performance. We employ panel data regressions to a longitudinal dataset of the world's largest automobile manufacturers. Our findings suggest that executing digital M&A contributes to building the digital knowledge base of industrial-age firms, which in turn enables them to drive digital innovation. Our findings further indicate that digital innovation improves firm performance of industrial-age firms. We discuss implications for information systems research about M&A and digital innovation as well as recommendations for managerial practice

    DISCOVERING NEW DIGITAL BUSINESS MODEL TYPES – A STUDY OF TECHNOLOGY STARTUPS FROM THE MOBILITY SECTOR

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    In the 1990s, the broad diffusion of the internet allowed firms such as Amazon, eBay, and Google to invent new digital business models. Since then, research has formalized recurring configurations as digital business model types, still frequently being used to analyze existing business models and develop new ones. Now, the next wave of digital transformation – enabled by ongoing improvements in processing power, the miniaturization of hardware, and ubiquitous wireless connectivity – is again driving innovation. For instance, in the mobility sector, startups such as Uber, Turo, and Streetline have formed business logics that cannot be understood with existing types. Therefore, we identified and formalized new business model configurations by systematically analyzing a comprehensive data set of technology startups from the US mobility sector. We found that, in order to adequately account for the new digital logics, 14 digital business model types must be added to existing collections: app developer, autonomous products/robots manufacturer, data analytics provider, integrator of third-party services, IT-enabled self-service provider, IT-guided service provider, manufacturer of connected physical products, manufacturer of connectivity devices for physical products, mobilized service provider, P2P goods sharing platform, P2P information sharing community, P2P service provision platform, seller of sensor information, and sensor-enabled service innovator

    Digital Transformation of Primarily Physical Industries - Exploring the Impact of Digital Trends on Business Models of Automobile Manufacturers

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    The phenomenon of digital transformation received some attention in previous literature concerning industries such as media, entertainment and publishing. However, there is a lack of understanding about digital transformation of primarily physical industries, whose products cannot be completely digitized, e.g., automotive industry. We conducted a rigorous content analysis of substantial secondary data from industry magazines aiming to generate insights to this phenomenon in the automotive industry. We examined the impact of major digital trends on dominant business models. Our findings indicate that trends related to social media, mobile, big data and cloud computing are driving automobile manufactures to extend, revise, terminate, and create business models. By doing so, they contribute to the constitution of a digital layer upon the physical mobility infrastructure. Despite its strong foundation in the physical world, the industry is undergoing important structural changes due to the ongoing digitalization of consumer lives and business

    Efficient evaluation of a gene containment system for poplar through early flowering induction

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    [EN] Key message The early flowering system HSP::AtFT allowed a fast evaluation of a gene containment system based on the construct PsEND1::barnase-barstar for poplar. Transgenic lines showed disturbed pollen development and sterility. Vertical gene transfer through pollen flow from transgenic or non-native plant species into their crossable natural relatives is a major concern. Gene containment approaches have been proposed to reduce or even avoid gene flow among tree species. However, evaluation of genetic containment strategies for trees is very difficult due to the long-generation times. Early flowering induction would allow faster evaluation of genetic containment in this case. Although no reliable methods were available for the induction of fertile flowers in poplar, recently, a new early flowering approach was developed. In this study, early flowering poplar lines containing the gene construct PsEND1::barnase-barstar were obtained. The PsEND1 promoter was chosen due to its early expression pattern, its versality and efficiency for generation of male-sterile plants fused to the barnase gene. RT-PCRs confirmed barnase gene activity in flowers, and pollen development was disturbed, leading to sterile flowers. The system developed in this study represents a valuable tool for gene containment studies in forest tree species.Open Access funding provided by Projekt DEAL. This work was funded with a scholarship by the Deutscher Akademischer Austauschdienst (DAAD). We thank S. Bein, D. Ebbinghaus, and A. Worm for helpful technical assistance in the laboratory, and the greenhouse staff (M. Hunger, G. Wiemann, R. Ebbinghaus, and M. Spauszus) for plant cultivation.Briones, MV.; Hoenicka, H.; Cañas Clemente, LA.; Beltran Porter, JP.; Hanelt, D.; Sharry, S.; Fladung, M. (2020). Efficient evaluation of a gene containment system for poplar through early flowering induction. 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    Ultraviolet radiation shapes seaweed communities

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    Disruption on the Way? The Role of Mobile Applications for Electric Vehicle Diffusion

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    Disruptive eco-innovations that replace existing unsustainable modes of transportation could contribute to achieve substantial improvements in environmental sustainability. Electric vehicles (EVs) have the potential to provide a more sustainable means of individual mobility, but, thus far, customer adoption remains relatively low. Following disruptive innovations theory developed by Christensen, the disruptive potential of EVs can be realized if their performance on traditional attributes that customer\u27s value improves. Here, information systems can play a key role. In this paper, we use a large scale (n = 1461) empirical investigation to examine which attributes must be addressed and assess the ability of existing mobile applications (apps) to do so. Our results indicate that apps contribute to a more reliable and convenient EV-user experience. We shed light on the role of apps in connecting the vehicle, the infrastructure and the user and in creating a digital eco-system that enhances the diffusion of EVs

    Measurement of nuclide cross-sections of spallation residues in 1 A GeV 238U + proton collisions

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    The production of heavy nuclides from the spallation-evaporation reaction of 238U induced by 1 GeV protons was studied in inverse kinematics. The evaporation residues from tungsten to uranium were identified in-flight in mass and atomic number. Their production cross-sections and their momentum distributions were determined. The data are compared with empirical systematics. A comparison with previous results from the spallation of 208Pb and 197Au reveals the strong influence of fission in the spallation of 238U.Comment: 20 pages, 10 figures, background information at http://www-wnt.gsi.de/kschmidt
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