450 research outputs found

    Non-pluripolar energy and the complex Monge-Ampere operator

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    Given a domain Omega subset of C-n we introduce a class of plurisubharmonic (psh) functions G(Omega) and Monge-Ampere operators u -> [dd(c)u](p), p <= n, on G(Omega) that extend the Bedford-Taylor-Demailly Monge-Ampere operators. Here [dd(c)u](p) is a closed positive current of bidegree (p, p) that dominates the non-pluripolar Monge-Ampere current < dd(c)u >(p). We prove that [dd(c)u](p) is the limit of Monge-Ampere currents of certain natural regularizations of u. On a compact Kahler manifold (X, omega) we introduce a notion of non-pluripolar energy and a corresponding finite energy class G(X, omega) subset of PSH(X, omega) that is a global version of the class G(Omega). From the local construction we get global Monge-Ampere currents [dd(c)phi + omega](p) for phi is an element of G(X, omega) that only depend on the current dd(c)phi + omega. The limits of Monge-Ampere currents of certain natural regularizations of phi can be expressed in terms of [dd(c)phi + omega](j) for j <= p. We get a mass formula involving the currents [dd(c)phi + omega](p) that describes the loss of mass of the non-pluripolar Monge-Ampere measure < dd(c)phi + omega >(n). The class G(X, omega) includes omega-psh functions with analytic singularities and the class E(X, omega) of omega-psh functions of finite energy and certain other convex energy classes, although it is not convex itself

    Parameters influencing hydrophobization of paper by surface sizing

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    Paper surface hydrophobization, also referred to as "surface sizing", is often necessary for printing and packaging purposes. Typically, hydrophobic polymeric nanoparticles, in combination with starch are applied on the paper surface at the dry-end of the paper machine. In the surface sizing process, the nature of the nanoparticles, starch type, starch concentration and ratio between starch and nanoparticles, paper quality, ionic strength, and application as well as drying temperature are parameters that influence the result. The aim of this work was to systematically evaluate these parameters in order to create knowledge to be used for optimization of the process. Laboratory scale surface sizing trials were performed and the results from the trials showed that cationic particles gave superior performance compared to anionic particles. Both the starch type and the concentration of the oxidized starch had an impact on the performance. The effect of the ionic strength was found to depend on the particle charge: for cationic particles, the addition of salt was detrimental while for the anionic particles it was beneficial. An increase of the application or the drying temperature was found to enhance the performance up to a temperature around the glass transition temperature of the polymer

    Young Peoples’ Online Science Practices as a Gateway to Higher Education STEM

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    The purpose of this manuscript is to explore how students perceive that online practices have enabled their participation in university physics programmes. In order to conceptualise how students bridge their science participation across physical and online spaces, we make use of the learning ecology perspective. This perspective is complemented with the notion of science capital, analysing how students have been able to strengthen different aspects of science capital through online participation. Data has been generated through semi-structured interviews guided by a timeline, constructed in collaboration between the interviewer and the interviewee. Twenty-one students enrolled in higher education physics have been interviewed, with a focus on their trajectories into higher education physics. The findings focus on four students who in various ways all have struggled to access science learning resources and found ways to utilise online spaces as a complement to their physical learning ecologies. In the manuscript, we show how online practices have contributed to the students’ learning ecologies, e.g. in terms of building networks and functioning as learning support, and how resources acquired through online science practices have both use and exchange value in the wider science community. Online science participation is thus both curiosity driven and founded in instrumental reasons (using online tutoring to pass school science). Furthermore, we argue that online spaces have the potential to offer opportunities for participation and network building for students who do not have access to science activities and science people in their everyday surroundings.The purpose of this manuscript is to explore how students perceive that online practices have enabled their participation in university physics programmes. In order to conceptualise how students bridge their science participation across physical and online spaces, we make use of the learning ecology perspective. This perspective is complemented with the notion of science capital, analysing how students have been able to strengthen different aspects of science capital through online participation. Data has been generated through semi-structured interviews guided by a timeline, constructed in collaboration between the interviewer and the interviewee. Twenty-one students enrolled in higher education physics have been interviewed, with a focus on their trajectories into higher education physics. The findings focus on four students who in various ways all have struggled to access science learning resources and found ways to utilise online spaces as a complement to their physical learning ecologies. In the manuscript, we show how online practices have contributed to the students’ learning ecologies, e.g. in terms of building networks and functioning as learning support, and how resources acquired through online science practices have both use and exchange value in the wider science community. Online science participation is thus both curiosity driven and founded in instrumental reasons (using online tutoring to pass school science). Furthermore, we argue that online spaces have the potential to offer opportunities for participation and network building for students who do not have access to science activities and science people in their everyday surroundings

    Glyceraldehyde as an efficient chemical crosslinker agent for the formation of chitosan hydrogels

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    The rheological changes that occur during the chemical gelation of semidilute solutions of chitosan in the presence of the low‐toxicity agent glyceraldehyde (GCA) are presented and discussed in detail. The entanglement concentration for chitosan solutions was found to be approximately 0.2 wt.% and the rheological experiments were carried out on 1 wt.% chitosan solutions with various amounts of GCA at different temperatures (25 \ub0C and 40 \ub0C) and pH values (4.8 and 5.8). High crosslinker concentration, as well as elevated temperature and pH close to the pKa value (pH ≈ 6.3–7) of chitosan are three parameters that all accelerate the gelation process. These conditions also promote a faster solid‐like response of the gel‐network in the post‐gel region after long curing times. The mesh size of the gel‐network after a very long (18 h) curing time was found to contract with increasing level of crosslinker addition and elevated temperature. The gelation of chitosan in the presence of other chemical crosslinker agents (glutaraldehyde and genipin) is discussed and a comparison with GCA is made. Small angle neutron scattering (SANS) results reveal structural changes between chitosan solutions, incipient gels, and mature gels

    A tool for holistic assessment of digitalization capabilities in manufacturing SMEs

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    In a constantly evolving global market, manufacturing companies need to be flexible and adaptive to survive. Digital twins of production systems have been proposed as one part of the solution, however this comes with multiple challenges. Manufacturing SMEs have limited resources and need to direct their efforts in this area wisely. This paper presents a tool for holistic assessment of an SME manufacturer\u27s level of digitalization, in order to visualize current gaps and guide digitalization efforts over a production system\u27s life cycle. The tool was empirically developed together with Manufacturing SMEs and has strengthened their digitalization awareness and capabilities

    FMN reduces Amyloid-β toxicity in yeast by regulating redox status and cellular metabolism

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    Alzheimer\u27s disease (AD) is defined by progressive neurodegeneration, with oligomerization and aggregation of amyloid-β peptides (Aβ) playing a pivotal role in its pathogenesis. In recent years, the yeast Saccharomyces cerevisiae has been successfully used to clarify the roles of different human proteins involved in neurodegeneration. Here, we report a genome-wide synthetic genetic interaction array to identify toxicity modifiers of Aβ42, using yeast as the model organism. We find that FMN1, the gene encoding riboflavin kinase, and its metabolic product flavin mononucleotide (FMN) reduce Aβ42 toxicity. Classic experimental analyses combined with RNAseq show the effects of FMN supplementation to include reducing misfolded protein load, altering cellular metabolism, increasing NADH/(NADH + NAD+) and NADPH/(NADPH + NADP+) ratios and increasing resistance to oxidative stress. Additionally, FMN supplementation modifies Htt103QP toxicity and α-synuclein toxicity in the humanized yeast. Our findings offer insights for reducing cytotoxicity of Aβ42, and potentially other misfolded proteins, via FMN-dependent cellular pathways

    The UV Dose Used for Disinfection of Drinking Water in Sweden Inadequately Inactivates Enteric Virus with Double-Stranded Genomes

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    Irradiation with ultraviolet light (UV) at 254 nm is effective in inactivating a wide range of human pathogens. In Sweden, a UV dose of 400 J/m2 is often used for the treatment of drinking water. To investigate its effect on virus inactivation, enteric viruses with different genomic organizations were irradiated with three UV doses (400, 600, and 1000 J/m2), after which their viability on cell cultures was examined. Adenovirus type 2 (double-stranded DNA), simian rotavirus 11 (double-stranded RNA), and echovirus 30 (single-stranded RNA) were suspended in tap water and pumped into a laboratory-scale Aquada 1 UV reactor. Echovirus 30 was reduced by 3.6-log10 by a UV dose of 400 J/m2. Simian rotavirus 11 and adenovirus type 2 were more UV resistant with only 1-log10 reduction at 400 J/m2 and needed 600 J/m2 for 2.9-log10 and 3.1-log10 reductions, respectively. There was no significant increase in the reduction of viral viability at higher UV doses, which may indicate the presence of UV-resistant viruses. These results show that higher UV doses than those usually used in Swedish drinking water treatment plants should be considered in combination with other barriers to disinfect the water when there is a risk of fecal contamination of the water

    Design Thinking for Entrepreneurship in Frugal Contexts

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    Even if design is recognized as an important driver for innovation on a global scale, there are still many countries in the developing part of the world where design as a process for innovation do not play any significant role for businesses and society. There is however a growing interest in design as a resource for innovation in many developing countries, e.g. in Kenya, where these projects are taking place. The results illustrate how design can support a local network by establishing a co-creation process as the basis for innovations and entrepreneurship in a frugal context, the role and value of design thinking for supporting entrepreneurs. The experiences and learnings from frugal innovations are of equal importance as the process and mindset of Design Thinking. A new type of Knowledge Cluster therefore includes not only design knowledge and skills, but also frugal innovation and frugal criteria

    Perception of the visual environment

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    The eyes are the front end to the vast majority of the human behavioural repertoire. The manner in which our eyes sample the environment places fundamental constraints upon the information that is available for subsequent processing in the brain: the small window of clear vision at the centre of gaze can only be directed at an average of about three locations in the environment in every second. We are largely unaware of these continual movements, making eye movements a valuable objective measure that can provide a window into the cognitive processes underlying many of our behaviours. The valuable resource of high quality vision must be allocated with care in order to provide the right information at the right time for the behaviours we engage in. However, the mechanisms that underlie the decisions about where and when to move the eyes remain to be fully understood. In this chapter I consider what has been learnt about targeting the eyes in a range of different experimental paradigms, from simple stimuli arrays of only a few isolated targets, to complex arrays and photographs of real environments, and finally to natural task settings. Much has been learnt about how we view photographs, and current models incorporate low-level image salience, motor biases to favour certain ways of moving the eyes, higher-level expectations of what objects look like and expectations about where we will find objects in a scene. Finally in this chapter I will consider the fate of information that has received overt visual attention. While much of the detailed information from what we look at is lost, some remains, yet our understanding of what we retain and the factors that govern what is remembered and what is forgotten are not well understood. It appears that our expectations about what we will need to know later in the task are important in determining what we represent and retain in visual memory, and that our representations are shaped by the interactions that we engage in with objects

    Evaluation of Effects of Continuous Glucose Monitoring on Physical Activity Habits and Blood Lipid Levels in Persons With Type 1 Diabetes Managed With MDI: An Analysis Based on the GOLD Randomized Trial (GOLD 8)

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    Background: People with type 1 diabetes generally view it easier to exercise when having continuous information of the glucose levels. We evaluated whether patients with type 1 diabetes managed with multiple daily insulin injections (MDI) exercised more after initiating continuous glucose monitoring (CGM) and whether the improved glycemic control and well-being associated with CGM translates into improved blood lipids and markers of inflammation. Method: The GOLD trial was a randomized cross-over trial over 16 months where patients used either CGM or capillary self-monitoring of blood glucose (SMBG) over six months, with a four-month wash-out period between the two treatment periods. We compared grade of physical activity, blood lipids, apolipoproteins, and high-sensitivity C-reactive protein (hsCRP) levels during CGM and SMBG. Results: There were 116 patients with information of physical activity estimated by the International Physical Activity Questionnaire (IPAQ) during both CGM and SMBG. No changes were found during CGM or SMBG, IPAQ scores 3305 versus 3878 (P =.16). In 136 participants with information of blood lipid levels with no change in lipid-lowering medication during the two treatment periods, HbA1c differed by 4.2 mmol/mol (NGSP 0.39%) between SMBG and CGM treatment (P <.001). No significant changes existed in low-density lipoprotein, high-density lipoprotein, triglycerides, total cholesterol, apolipoprotein A1, apolipoprotein B1, or hsCRP, during CGM and SMBG. Conclusion: Although many patients experience it easier to perform physical activity when monitoring glucose levels with CGM, it does not influence the amount of physical activity in persons with type 1 diabetes. Blood lipids, apolipoprotein, and hsCRP levels were similar during CGM and SMBG
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