368 research outputs found

    Quasi-exactly solvable quartic: real algebraic spectral locus

    Full text link
    We describe the real quasi-exactly solvable spectral locus of the PT-symmetric quartic using the Nevanlinna parametrization.Comment: 17 pages, 11 figure

    On eigenvalues of the Schr\"odinger operator with an even complex-valued polynomial potential

    Full text link
    In this paper, we generalize several results of the article "Analytic continuation of eigenvalues of a quartic oscillator" of A. Eremenko and A. Gabrielov. We consider a family of eigenvalue problems for a Schr\"odinger equation with even polynomial potentials of arbitrary degree d with complex coefficients, and k<(d+2)/2 boundary conditions. We show that the spectral determinant in this case consists of two components, containing even and odd eigenvalues respectively. In the case with k=(d+2)/2 boundary conditions, we show that the corresponding parameter space consists of infinitely many connected components

    Observing, Coaching and Reflecting: A Multi-modal Natural Language-based Dialogue System in a Learning Context

    Get PDF
    The Metalogue project aims to develop a multi-modal, multi-party dialogue system with metacognitive abilities that will advance our understanding of natural conversational human-machine interaction and dialogue interfaces. This paper introduces the vision for the system and discusses its application in the context of debate skills training where it has the potential to provide learners with a rich, immersive experience. In particular, it considers a potentially powerful learning analytics tool in the form of a performance reflection dashboard

    Quasi-exactly solvable quartic: elementary integrals and asymptotics

    Full text link
    We study elementary eigenfunctions y=p exp(h) of operators L(y)=y"+Py, where p, h and P are polynomials in one variable. For the case when h is an odd cubic polynomial, we found an interesting identity which is used to describe the spectral locus. We also establish some asymptotic properties of the QES spectral locus.Comment: 20 pages, 1 figure. Added Introduction and several references, corrected misprint

    Technology experience café - enabling technology - driven social innovation for an ageing society

    Get PDF
    Effective technology innovation process management in the context of active healthy ageing has the potential to improve older adults’ quality of life, allowing them to maintain their independence and age in their own homes for longer. But as older adults significantly differ from the general population in technology use and its impact on their quality of life, tools are needed that (1) involve this target group into the innovation process, as well as (2) capture the diverse needs of technology for various stakeholders involved in this process. This paper presents the framework called Technology Experience Café (TEC), developed within the European project SIforAGE, answering exactly this need. Detailed information on the methodology and its implementation in five sites, in four different countries across Europe, focusing on participating stakeholders, general design of the TEC, and used evaluation tools, is provided. Preliminary results show, that (1) the target group’s perception of the TEC as a framework was thoroughly positive and TECs had a positive impact on older adults’ technology related attitudes and (2) that stakeholders’ benefits affiliated with their involvement in the TECs are manifold. Implications and limitations are discussed

    Transcriptome and metabolome profiling identify factors potentially involved in pro-vitamin A accumulation in cassava landraces

    Get PDF
    Open Access ArticleCassava (Manihot esculenta Crantz) is a predominant food security crop in several developing countries. Its storage roots, rich in carbohydrate, are deficient in essential micronutrients, including provitamin A carotenoids. Increasing carotenoid content in cassava storage roots is important to reduce the incidence of vitamin A deficiency, a public health problem in sub-Saharan Africa. However, cassava improvement advances slowly, mainly due to limited information on the molecular factors influencing β-carotene accumulation in cassava. To address this problem, we performed comparative transcriptomic and untargeted metabolic analyses of roots and leaves of eleven African cassava landraces ranging from white to deep yellow colour, to uncover regulators of carotenoid biosynthesis and accumulation with conserved function in yellow cassava roots. Sequence analysis confirmed the presence of a mutation, known to influence β-carotene content, in PSY transcripts of deep yellow but not of pale yellow genotypes. We identified genes and metabolites with expression and accumulation levels significantly associated with β-carotene content. Particularly an increased activity of the abscisic acid catabolism pathway together with a reduced amount of L-carnitine, may be related to the carotenoid pathway flux, higher in yellow than in white storage roots. In fact, NCED_3.1 was specifically expressed at a lower level in all yellow genotypes suggesting that it could be a potential target for increasing carotenoid accumulation in cassava. These results expand the knowledge on metabolite compositions and molecular mechanisms influencing carotenoid biosynthesis and accumulation in cassava and provide novel information for biotechnological applications and genetic improvement of cassava with high nutritional values

    Air temperature changes in Toruń (central Poland) from 1871 to 2010

    Get PDF
    The article presents a detailed analysis of changes in air temperature in Toruń in the period 1871–2010 on the basis of homogenised monthly, seasonal and annual air temperature series which have been newly constructed (i.e. extended by the 50 years of 1871–1920). Over the 140-year study period, a sizeable and statistically significant increase of 0.1 °C per decade was found in the air temperature in Toruń. The greatest increases occurred for spring and winter, at 0.12 and 0.11 °C, respectively. A lesser warming, meanwhile, was recorded for autumn (0.10 °C/10 years), and particularly for summer (0.07 °C/10 years). The air temperature trends are statistically significant for all seasons. Air temperature differences between the monthly averages of three analysed subperiods (1871–1900, 1901–1950 and 1951–2010) and averages for the entire period under review rarely exceeded ± 0.5 °C. In all of these periods, the highest average air temperatures occurred in July and the lowest in January. The period of 1981–2010 had the highest frequency of occurrence of very and extremely warm seasons and years. Meanwhile, the highest frequency of very and extremely cool seasons and years was recorded in the 1940s and in the nineteenth century. In the period of 1871–2010, winters shortened markedly (by 7%) and summers lengthened by 3.8%. All of the presented aspects of air temperature in Toruń, which is representative of the climate of central Poland, are in close agreement with the findings of analogous studies of the same for other areas of Poland and Central Europe

    Variability in fluvial suspended and streambed sediment phosphorus fractions among small agricultural streams

    Get PDF
    Agriculture is a major source of sediment and particulate phosphorus (P) inputs to freshwaters. Distinguishing between P fractions in sediment can aid in understanding its eutrophication risk. Although streams and rivers are important parts of the P cycle in agricultural catchments, streambed sediment and especially fluvial suspended sediment (FSS) and its P fractions are less studied. To address this knowledge gap, seasonal variations in FSS P fractions and their relation to water quality and streambed sediment were examined in three Swedish agricultural headwater catchments over 2 yr. Sequential fractionation was used to characterize P fractions in both streambed sediment and FSS. All catchments had similar annual P losses (0.4-0.8 kg ha(-1)), suspended solids (124-183 mg L-1), and FSS total P concentrations (1.15-1.19 mg g(-1)). However, distribution of P fractions and the dominant P fractions in FSS differed among catchments (p < .05), which was most likely dependent on differences in catchment geology, clay content, external P sources, and flow conditions. The most prominent seasonal pattern in all catchments was found for iron-bound P, with high concentrations during low summer flows and low concentrations during winter high flows. Streambed sediment P fractions were in the same concentration ranges as in FSS, and the distribution of the fractions differed between catchments. This study highlights the need to quantify P fractions, not just total P in FSS, to obtain a more complete understanding of the eutrophication risk posed by agricultural sediment losses
    corecore