22 research outputs found

    Hydrodynamic limit of multiscale viscoelastic models for rigid particle suspensions

    Full text link
    We study the multiscale viscoelastic Doi model for suspensions of Brownian rigid rod-like particles, as well as its generalization by Saintillan and Shelley for self-propelled particles. We consider the regime of a small Weissenberg number, which corresponds to a fast rotational diffusion compared to the fluid velocity gradient, and we analyze the resulting hydrodynamic approximation. More precisely, we show the asymptotic validity of macroscopic nonlinear viscoelastic models, in form of so-called ordered fluid models, as an expansion in the Weissenberg number. The result holds for zero Reynolds number in 3D and for arbitrary Reynolds number in 2D. Along the way, we establish several new well-posedness and regularity results for nonlinear fluid models, which may be of independent interest.Comment: 64 page

    Report from a krill focused survey with RV Kronprins Haakon and land-based predator work in Antarctica during 2018/2019

    Get PDF
    The primary objective for this krill research activity was twofold 1) to conduct a survey that provides updated estimates of the biomass and distribution of krill which are used in models to estimate sustainable yield in CCAMLR Area 48 and 2) to develop knowledge on the marine environment essential for the implementation of a Feed-Back Management (FBM) system. The survey follows a similar design as a survey initiated by CCAMLR in year 2000 for comparative purposes, but in addition focuses on high krill-density areas, contains state-of-the art methods and employs modern technology for the research topics currently in focus. In terms of FBM, Marine Protected Area (MPA) development in CCAMLR Planning Domain 1 encompasses the major krill fishing grounds. Thus, data supporting FBM are critical if the fishery is to be managed by an empirical understanding of krill density, distribution, availability and predator needs as opposed to purely conservation-based measures. A future developed FBM system, requires acoustic data to be collected, processed and reported continuously during the fishing season as a measure of the available prey field. This information can be integrated with finer-scale knowledge of krill predator feeding strategies and updated through specific scientific studies at regular (multiyear) intervals. The survey and coupled FBM process studies took place during the Austral summer 2018-2019. The work was coordinated by Norway and involved collaborative international efforts as well as vessels from Norway, Association of Responsible Krill fishing companies (ARK) and the Norwegian fishing company Aker BioMarine AS, China, Korea, Ukraine and United Kingdom. This report presents preliminary results from the survey performed with the Norwegian RV Kronprins Haakon during 08th January – 24th February 2019 and the land-based predator research carried out between 21st November 2018 and 20th February 2019.publishedVersio

    Lista das espécies de aranhas (Arachnida, Araneae) do estado do Rio Grande do Sul, Brasil

    Full text link

    Knowledge Sells? How the quality of sales knowledge assets in startups affects their scalability

    No full text
    A goal of entrepreneurship is to foster innovation through the creation of sustainable, scalable firms through a successful commercialization of their value proposal. Surprisingly there is little research on the key role sales and hence sales knowledge of the founder plays in the survival of an entrepreneurial venture. The purpose of this study is twofold. First, we aim to contribute to the wider body of knowledge by exploring the effects of knowledge management on startups, using a field of knowledge topic highly appealing to our research interest and relevant for entrepreneurship: sales. Second, we want to scrutinize how the quality of startup founders’ sales knowledge and their way of creating knowledge determines their ability to develop scalable business processes grounded on their implemented sales process. To do so, we undertook a qualitative multiple case-study based on eight interviews with startup founder- managers, with and without previous professional experience in sales who are in either year 1 or year 3+ of their startups life cycle with the intention of isolating the experience factor and to better analyze its effect on the quality of given knowledge. This way we seek to determine if previous professional experience in sales can be equalized to the sales knowledge gained through experience in the startup itself and how this affects scalability of the firm overall, using the framework of Knowledge Management (KM) and the SECI model to support the analysis of the collected data. We identify an interesting difference between sales processes implemented by founder-managers with tacit-leaning and founder-managers with more balanced knowledge assets, as the later have achieved to build efficient sales funnels that are scalable in size and scale. Founder-managers with tacit-leaning sales process knowledge on the other side struggle with the efficiency of their sales process. A major determinant here seems to previous professional experience as the experience gained within the startup itself would not leverage in the same way. Our findings emphasize the need for startups to more systematically approach knowledge management practices in order to create more balanced knowledge assets; something investors as well as scholars might benefit from when investing and educating the next generation of entrepreneurs

    Taxonomic remarks on the genus Cupiennius Simon (Araneae, Ctenidae) and description of C. vodou sp. nov. from Haiti

    No full text
    Ctenus bimaculatus Taczanowski, 1874, is removed from the synonymy of Ancylometes rufus (Walkenaer, 1837) and transferred to the genus Cupiennius Simon, 1891, in which it is placed as a senior synonym of Cupiennius celerrimus Simon, 1891. New records are presented for C. bimaculatus (TACZANOWSKI 1874) and a new species, C. vodou, is described from Haiti.<br>Ctenus bimaculatus Taczanowski, 1874, é removido da sinonímia de Ancylometes rufus (Walkenaer, 1837) e transferido para o gênero Cupiennius Simon, 1891, no qual é considerado sinônimo sênior de Cupiennius celerrimus Simon, 1891. São apresentados novos registros para C. bimaculatus (Taczanowski, 1874) e uma nova espécie, C. vodou, é descrita para o Haiti

    Evolution of Eocene to Oligocene arc-related volcanism in the North Patagonian Andes (39-41°S), prior to the break-up of the Farallon plate

    Get PDF
    Voluminous Paleogene magmatic rocks (44 to 29 Ma) are found in a retroarc position in the Northern Patagonian to Southern Central Andes (~ 39–42°S), whose origin remains controversial. Geochemical data in these Eocene to Oligocene volcanic associations are herein used to unravel their origin and understand changes in subduction parameters. Geochemical signatures indicate arc-related associations and reflect changing geodynamic boundary conditions of the Andean margin through time. In particular, Eocene magmatism (~ 44 Ma; Pilcaniyeu Belt) shows an alkaline-like signature and limited slab influence. Reported contemporaneous within-plate magmatism (~ 47–43 Ma) in an easternmost position reflects a more typical enriched source. Oligocene arc-like volcanism (~ 29 Ma; El Maitén Belt), which developed in an extensional retroarc setting, shows a higher contribution from slab-derived fluids and a calc-alkaline source. A comparison with younger arc-related magmas from the region (~ 26–20 Ma), emplaced in an intra- to retroarc position (Cura Mallín and Abanico basins), indicates a progressive increase in slab-signature, associated with a tholeiitic magma source. We propose that these compositional variations could be directly related to changes in plate configuration before and after the Farallon plate break-up and the initiation of a more orthogonal convergence typical of the present Andean-type subduction zone.Fil: Iannelli, Sofía. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos ; ArgentinaFil: Litvak, Vanesa Dafne. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos ; ArgentinaFil: Fernández Paz, Lucía. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos ; ArgentinaFil: Folguera Telichevsky, Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos ; ArgentinaFil: Ramos, Miguel Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos ; ArgentinaFil: Ramos, Miguel Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos ; Argentin

    Report from a krill focused survey with RV Kronprins Haakon and land-based predator work in Antarctica during 2018/2019

    No full text
    The primary objective for this krill research activity was twofold 1) to conduct a survey that provides updated estimates of the biomass and distribution of krill which are used in models to estimate sustainable yield in CCAMLR Area 48 and 2) to develop knowledge on the marine environment essential for the implementation of a Feed-Back Management (FBM) system. The survey follows a similar design as a survey initiated by CCAMLR in year 2000 for comparative purposes, but in addition focuses on high krill-density areas, contains state-of-the art methods and employs modern technology for the research topics currently in focus. In terms of FBM, Marine Protected Area (MPA) development in CCAMLR Planning Domain 1 encompasses the major krill fishing grounds. Thus, data supporting FBM are critical if the fishery is to be managed by an empirical understanding of krill density, distribution, availability and predator needs as opposed to purely conservation-based measures. A future developed FBM system, requires acoustic data to be collected, processed and reported continuously during the fishing season as a measure of the available prey field. This information can be integrated with finer-scale knowledge of krill predator feeding strategies and updated through specific scientific studies at regular (multiyear) intervals. The survey and coupled FBM process studies took place during the Austral summer 2018-2019. The work was coordinated by Norway and involved collaborative international efforts as well as vessels from Norway, Association of Responsible Krill fishing companies (ARK) and the Norwegian fishing company Aker BioMarine AS, China, Korea, Ukraine and United Kingdom. This report presents preliminary results from the survey performed with the Norwegian RV Kronprins Haakon during 08th January – 24th February 2019 and the land-based predator research carried out between 21st November 2018 and 20th February 2019
    corecore