401 research outputs found

    Koszul binomial edge ideals

    Full text link
    It is shown that if the binomial edge ideal of a graph GG defines a Koszul algebra, then GG must be chordal and claw free. A converse of this statement is proved for a class of chordal and claw free graphs

    The curve of lines on a prime Fano threefold of genus 8

    Full text link
    We show that a general prime Fano threefold X of genus 8 can be reconstructed from the pair (Γ,L)(\Gamma,L), where Γ\Gamma is its Fano curve of lines and L=OΓ(1)L=O_{\Gamma}(1) is the theta-characteristic which gives a natural embedding \Gamma \subset \matbb{P}^5.Comment: 24 pages, misprints corrected, to appear in International Journal of Mathematic

    Decompactifications and Massless D-Branes in Hybrid Models

    Full text link
    A method of determining the mass spectrum of BPS D-branes in any phase limit of a gauged linear sigma model is introduced. A ring associated to monodromy is defined and one considers K-theory to be a module over this ring. A simple but interesting class of hybrid models with Landau-Ginzburg fibres over CPn are analyzed using special Kaehler geometry and D-brane probes. In some cases the hybrid limit is an infinite distance in moduli space and corresponds to a decompactification. In other cases the hybrid limit is at a finite distance and acquires massless D-branes. An example studied appears to correspond to a novel theory of supergravity with an SU(2) gauge symmetry where the gauge and gravitational couplings are necessarily tied to each other.Comment: PDF-LaTeX, 34 pages, 2 mps figure

    Support varieties for selfinjective algebras

    Full text link
    Support varieties for any finite dimensional algebra over a field were introduced by Snashall-Solberg using graded subalgebras of the Hochschild cohomology. We mainly study these varieties for selfinjective algebras under appropriate finite generation hypotheses. Then many of the standard results from the theory of support varieties for finite groups generalize to this situation. In particular, the complexity of the module equals the dimension of its corresponding variety, all closed homogeneous varieties occur as the variety of some module, the variety of an indecomposable module is connected, periodic modules are lines and for symmetric algebras a generalization of Webb's theorem is true

    Diversity of hard-bottom fauna relative to environmental gradients in Kongsfjorden, Svalbard

    Get PDF
    A baseline study of hard-bottom zoobenthos in relation to environmental gradients in Kongsfjorden, a glacial fjord in Svalbard, is presented, based on collections from 1996 to 1998. The total species richness in 62 samples from 0 to 30 m depth along five transects was 403 species. Because 32 taxa could not be identified to species level and because 11 species are probably new to science, the total number of identified species was 360. Of these, 47 species are new for Svalbard waters. Bryozoa was the most diverse group. Biogeographic composition revealed features of both Arctic and sub-Arctic properties of the fauna. Species richness, frequency of species occurrence, mean abundance and biomass generally decreased towards the tidal glaciers in inner Kongsfjorden. Among eight environmental factors, depth was most important for explaining variance in the composition of the zoobenthos. The diversity was consistently low at shallow depths, whereas the non-linear patterns of species composition of deeper samples indicated a transitional zone between surface and deeper water masses at 15–20 m depth. Groups of “colonial” and “non-colonial” species differed in diversity, biogeographic composition and distribution by location and depth as well as in relation to other environmental factors. “Non-colonial” species made a greater contribution than “colonial” species to total species richness, total occurrence and biomass in samples, and were more influenced by the depth gradient. Biogeographic composition was sensitive to variation of zoobenthic characteristics over the studied depth range. A list of recorded species and a description of sampling sites are presented

    Automating unobtrusive personalized services in ambient media environments

    Full text link
    The final publication is available at Springer via http://dx.doi.org/10.1007/s11042-013-1634-2In the age of ambient media, people are surrounded by lots of physical objects (media objects) for rendering the digital world in the natural environment. These media objects should interact with users in a way that is not disturbing for them. To address this issue, this work presents a design and automation strategy for augmenting the world around us with personalized ambient media services that behave in a considerate manner. That is, ambient services are capable of adjusting its obtrusiveness level (i.e., the extent to which each service intrudes the user¿s mind) by using the appropriate media objects for each user¿s situation.This work has been developed with the support of MICINN, under the project EVERYWARE TIN2010-18011, and the support of the Christian Doppler Forschungsgesellschaft and the BMWFJ, Austria.Serral Asensio, E.; Gil Pascual, M.; Valderas Aranda, PJ.; Pelechano Ferragud, V. (2014). Automating unobtrusive personalized services in ambient media environments. Multimedia Tools and Applications. 71(1):159-178. https://doi.org/10.1007/s11042-013-1634-2S159178711Bencomo N, Grace P, Flores-Cortés CA, Hughes D, Blair GS (2008) Genie: supporting the model driven development of reflective, component-based adaptive systems. In: ICSE, pp 811–814Blumendorf M, Lehmann G, Albayrak S (2010) Bridging models and systems at runtime to build adaptive user interfaces. In: Proc. of EICS 2010. ACM, pp 9–18Brown DM (2010) Communicating design: developing web site documentation for design and planning, 2nd edn. New Riders PressCalinescu R (2011) When the requirements for adaptation and high integrity meet. In: Proceedings of the 8th workshop on assurances for self-adaptive systems, ASAS ’11. ACM, New York, pp 1–4Filieri A, Ghezzi C, Tamburrelli G (2011) Run-time efficient probabilistic model checking. In: Proceedings of the 33rd International Conference on Software Engineering, ICSE ’11. ACM, New York, pp 341–350Gershenfeld N, Krikorian R, Cohen D (2004) The internet of things. Sci Am 291(4):46–51Gibbs WW (2005) Considerate computing. Sci Am 292(1):54–61Gulliksen J, Goransson B, Boivie I, Blomkvist S, Persson J, Cajander A (2003) Key principles for user-centred systems design. Behav Inform Technol 22:397–409Hinckley K, Horvitz E (2001) Toward more sensitive mobile phones. In: Proc. of the UIST ’01, pp 191–192Ho J, Intille SS (2005) Using context-aware computing to reduce the perceived burden of interruptions from mobile devices. In: Proc. of CHI ’05. ACM, pp 909–918Horvitz E, Kadie C, Paek T, Hovel D (2003) Models of attention in computing and communication: from principles to applications. Commun ACM 46:52–59Ju W, Leifer L (2008) The design of implicit interactions: making interactive systems less obnoxious. Des Issues 24(3):72–84Kortuem G, Kawsar F, Fitton D, Sundramoorthy V (2010) Smart objects as building blocks for the internet of things. IEEE Internet Comput 14(1):44–51Lewis JR (1995) Ibm computer usability satisfaction questionnaires: psychometric evaluation and instructions for use. Int J Hum Comput Interact 7(1):57–78Lugmayr A, Risse T, Stockleben B, Laurila K, Kaario J (2009) Semantic ambient media—an introduction. Multimed Tools Appl 43(3):337–359Mattern F (2003) From smart devices to smart everyday objects. In: Proc. Smart Objects Conf. (SOC 03). Springer, pp 15–16Morin B, Barais O, Jezequel JM, Fleurey F, Solberg A (2009) Models run.time to support dynamic adaptation. Comput 42(10):44–51Nelson L, Churchill EF (2005) User experience of physical-digital object systems: implications for representation and infrastructure. Paper presented at smart object systems workshop, in cojunction with ubicomp 2005Paternò F (2002) Concurtasktrees: an engineered approach to model-based design of interactive systems. In: L.E. Associates (ed) The handbook of analysis for human-computer interaction, pp 483–500Paternò F (2003) From model-based to natural development. HCI International, pp 592–596Ramchurn SD, Deitch B, Thompson MK, Roure DCD, Jennings NR, Luck M (2004) Minimising intrusiveness in pervasive computing environments using multi-agent negotiation. MobiQuitous ’04, pp 364–372Runeson P, Höst M (2009) Guidelines for conducting and reporting case study research in software engineering. Empir Softw Eng 14(2):131–164Schmidt A (2000) Implicit human computer interaction through context. Pers Technol 4(2–3):191–199Serral E, Valderas P, Pelechano V (2010) Supporting runtime system evolution to adapt to user behaviour. In: Proc. of CAiSE’10, pp 378–392Serral E, Valderas P, Pelechano V (2010) Towards the model driven development of context-aware pervasive systems. PMC 6(2):254–280Siegemund F (2004) A context-aware communication platform for smart objects. In: Proc of the int conf on pervasive computing. Springer, pp 69–86Streitz NA, Rocker C, Prante T, Alphen Dv, Stenzel R, Magerkurth C (2005) Designing smart artifacts for smart environments. Comput 38(3):41–49. doi: 10.1109/MC.2005.92Thiesse F, Kohler M (2008) An analysis of usage-based pricing policies for smart products. Electron Mark 18(3):232–241. doi: 10.1080/10196780802265751Vastenburg MH, Keyson DV, de Ridder H (2008) Considerate home notification systems: a field study of acceptability of notifications in the home. Pers Ubiquit Comput 12(8):555–56

    Calf health and management in smallholder dairy farms in Tanzania

    Get PDF
    Smallholder farmers’ knowledge and practice of dairy calf management on 129 farms with calves less than 10 months of age in Southeastern and Southern Highland areas of Tanzania was assessed. The method of study included both a farm visit and completion of a questionnaire. Most of the farmers were female, with a primary level of education, and majority kept 1–3 milking cows that yielded 6–10 l milk/cow/day. Most of the calves were fed milk using a residual calf suckling system. Weaning age was 3–8 months. Overall, the body condition of the calves was poor, ranged from 1 to 2.5 with a mode of 2. The majority of the farmers believed that helminthosis was the most common disease condition affecting the calves; diarrhea was ranked as the second. Calf death was reported by 20% of the farmers to have occurred in their herd lasting the 2 years prior to the study. Calf body condition score was related to body weight for calves younger than 9 weeks, and older than 23 weeks of age, whereas no such relationship existed in the age group 9 to 23 weeks. The sex distribution was skewed with less male calves being older than 23 weeks. We hypothesize that male calves experience inferior management compared with female calves. This study demonstrates a low level of knowledge on, and poor practices of calf management among the surveyed farmers that suggest the need for educational intervention

    Advances in prevention and therapy of neonatal dairy calf diarrhoea : a systematical review with emphasis on colostrum management and fluid therapy

    Get PDF
    Neonatal calf diarrhoea remains the most common cause of morbidity and mortality in preweaned dairy calves worldwide. This complex disease can be triggered by both infectious and non-infectious causes. The four most important enteropathogens leading to neonatal dairy calf diarrhoea are Escherichia coli, rota-and coronavirus, and Cryptosporidium parvum. Besides treating diarrhoeic neonatal dairy calves, the veterinarian is the most obvious person to advise the dairy farmer on prevention and treatment of this disease. This review deals with prevention and treatment of neonatal dairy calf diarrhoea focusing on the importance of a good colostrum management and a correct fluid therapy
    • …
    corecore