NIR-Vis Up-Conversion Luminescence in the Yb3+,Er3+ Doped Y2O2S, ZrO2, and NaYF4 Nanomaterials

Since the discovery of the up-conversion phenomenon, there has been an ever increasing interest in up-converting phosphors in which the absorption of two or more low energy photons is followed by emission of a higher energy photon. Most up-conversion luminescence materials operate by using a combination of a trivalent rare earth (lanthanide) sensitizer (e.g. Yb or Er) and an activator (e.g. Er, Ho, Tm or Pr) ion in a crystal lattice. Up-converting phosphors have a variety of potential applications as lasers and displays as well as inks for security printing (e.g. bank notes and bonds). One of the most sophisticated applications of lanthanide up-conversion luminescence is probably in medical diagnostics. However, there are some major problems in the use of photoluminescence based on the direct UV excitation in immunoassays. Human blood absorbs strongly UV radiation as well as the emission of the phosphor in the visible. A promising way to overcome the problems arising from the blood absorption is to use a long wavelength excitation and benefit from the up-conversion luminescence. Since there is practically no absorption by the whole-blood in the near IR region, it has no capability for up-conversion in the excitation wavelength region of the conventional up-converting phosphor based on the Yb3+ (sensitizer) and Er3+ (activator) combination. The aim of this work was to prepare nanocrystalline materials with high red (and green) up-conversion luminescence efficiency for use in quantitative whole-blood immunoassays. For coupling to biological compounds, nanometer-sized (crystallite size below 50 nm) up-converting phosphor particles are required. The nanocrystalline ZrO2:Yb3+,Er3+, Y2O2S:Yb3+,Er3+, NaYF4:Yb3+,Er3+ and NaRF4-NaR’F4 (R: Y, Yb, Er) materials, prepared with the combustion, sol-gel, flux, co-precipitation and solvothermal synthesis, were studied using the thermal analysis, FT-IR spectroscopy, transmission electron microscopy, EDX spectroscopy, XANES/EXAFS measurements, absorption spectroscopy, X-ray powder diffraction, as well as up-conversion and thermoluminescence spectroscopies. The effect of the impurities of the phosphors, crystallite size, as well as the crystal structure on the up-conversion luminescence intensity was analyzed. Finally, a new phenomenon, persistent up-conversion luminescence was introduced and discussed. For efficient use in bioassays, more work is needed to yield nanomaterials with smaller and more uniform crystallite sizes. Surface modifications need to be studied to improve the dispersion in water. On the other hand, further work must be carried out to optimize the persistent up-conversion luminescence of the nanomaterials to allow for their use as efficient immunoassay nanomaterials combining the advantages of both up-conversion and persistent luminescence.Siirretty Doriast

Small-scale structures and grazing intensity in semi-natural pastures

Semi-natural grasslands characterized by nutrient poor soils are among the most species-rich habitats in Europe and they harbour many red-listed species. The area of semi-natural grasslands has decreased drastically due to intensified land use or abandonment of farms. Ceased grazing can lead to encroachment of shrubs and trees and reduced plant species richness. The aim of this thesis is to study the effects of spatial structures and grazing intensity on plant assemblages, plant reproduction and phytophagous insects. Pastures with scattered trees and shrubs grazed by cattle in south central Sweden were used as study sites. The studied spatial structures were two trees: Betula pendula, Pinus sylvestris, two shrubs: Juniperus communis, Rosa dumalis, and dung rejects, grazing rejects (ungrazed patches) and grazed patches. Trees and shrubs are long-lived structures and they significantly influenced plant assemblages. For example, R. dumalis shrubs had a positive effect on tall, grazing sensitive species and a negative effect on short, less competitive species. Structures that could function as grazing refuges, i.e. shrubs, dung and grazing rejects increased plant reproduction. Grazing intensity also had a strong effect on plant reproduction and intensive grazing decreased the quantity of flowers and fruits. The effect of spatial structures on four plant species of the Fabaceae family and their seed predators was also studied. The four species varied in abundance between the structures but in shrub rejects and dung rejects reproduction was higher than in grazed patches. The available oviposition places, i.e. pods, for seed predators were considerable higher in shrub and dung rejects than in grazed patches. But no clear patterns in predation rate between structures were found. For two species long pods were more predated than short pods indicating oviposition selection at pod level. In conclusion, regulation of grazing intensity and shrub cover are important tools when managing pastures for both plants and phytophagous insects

Beaver wetland and lake effects on Francisella tularensis in Swedish landscapes and hares

The zoonotic disease tularemia is caused by the bacterium Francisella tularensis that infects both humans and wildlife in Sweden. Associations between outbreaks of tularemia and lakes and rivers have earlier been observed, and semi-aquatic rodents and mosquitoes are believed to be key species groups in the epidemiological cycle of the disease. I have conducted a series of landscape analyses to assess land cover properties with focus on water availability at different spatial scales in areas of tularemia incidence, using data on hares found dead (n= 452) with known tularemia status, collected in 2016-2021, and land cover properties. As a complement, 56 water samples (biofilm and surface water) from lakes and beaver ponds in Sweden, covering latitudes from N 59° 29.0582’ in the south, to N 65° 52.4261’ in the north, were collected to investigate the occurrence of tularemia in different freshwater ecosystems. Results show significant correlations between tularemia occurrence and high soil moisture, and local proportion of inland water area. Water proximity as well as proportional wetland area both lack significant effects on tularemia status in hares. In water samples, I found F. tularensis in 11% of 56 samples, which were all taken from beaver systems. No difference in sampling depth could be found as F. tularensis was found in both biofilm and surface water. I suggest further investigations on F. tularensis in wetlands to a) assess the role of water biogeochemistry including pH, turbidity, and nutrient levels for occurrence and environmental persistence of the bacterium and b) evaluate the role of beaver systems for the epizootiology and epidemiology of tularemia with beavers as either reservoirs and/or beaver systems favoring vector (mosquito) habitat

Socratic Seminars for Students with Autism Spectrum Disorders

This paper explores the possibilities of the pedagogical use of Socratic dialogue as a basis for educating students diagnosed with autism. The Socratic dialogue is a particular pedagogical method used in educational settings to enhance student’s thinking and dialogic abilities. Research has proven that Socratic dialogue may result in improved language, interactive, and critical thinking abilities, as well as have effect on students’ self-evaluation. The social nature of dialogic learning may scaffold children with specific abilities to effectively interact with others and perceive those others’ emotions. Presently, education of students diagnosed with an Autism Spectrum Disorders (ASDs) use a variety of educational interventions, mostly inspired by behaviorist theory. These include little or no systematic use of dialogue as a pedagogical means of scaffolding students' abilities. However, several of these behaviorist methods have been tried out for a long period, educating students with ASDs, and have also proved to be successful to certain extents. In this article, we explore why and how Socratic dialogue can be used as an effective strategy for educating individuals diagnosed with autism. Hence, the investigation ends by introducing a dialogue-based teaching design that is compatible for children diagnosed with ASDs, to be explored and evaluate

Deep Perceptual Similarity is Adaptable to Ambiguous Contexts

The concept of image similarity is ambiguous, meaning that images that are considered similar in one context might not be in another. This ambiguity motivates the creation of metrics for specific contexts. This work explores the ability of the successful deep perceptual similarity (DPS) metrics to adapt to a given context. Recently, DPS metrics have emerged using the deep features of neural networks for comparing images. These metrics have been successful on datasets that leverage the average human perception in limited settings. But the question remains if they could be adapted to specific contexts of similarity. No single metric can suit all definitions of similarity and previous metrics have been rule-based which are labor intensive to rewrite for new contexts. DPS metrics, on the other hand, use neural networks which might be retrained for each context. However, retraining networks takes resources and might ruin performance on previous tasks. This work examines the adaptability of DPS metrics by training positive scalars for the deep features of pretrained CNNs to correctly measure similarity for different contexts. Evaluation is performed on contexts defined by randomly ordering six image distortions (e.g. rotation) by which should be considered more similar when applied to an image. This also gives insight into whether the features in the CNN is enough to discern different distortions without retraining. Finally, the trained metrics are evaluated on a perceptual similarity dataset to evaluate if adapting to an ordering affects their performance on established scenarios. The findings show that DPS metrics can be adapted with high performance. While the adapted metrics have difficulties with the same contexts as baselines, performance is improved in 99% of cases. Finally, it is shown that the adaption is not significantly detrimental to prior performance on perceptual similarity

The Gardener’s Practical Knowledge

With this article, I want to raise questions about the gardener’s practical knowledge in order to create greater awareness in educational contexts and working life of the importance and application of what it means to be and work as a gardener. Practical knowledge takes time to develop and requires experience and conscious reflection. It also requires knowledge of the particular site you are working with, which in principle is always complex, as it involves everything from natural habitats to human expressions, such as history. To understand what practical knowledge is, I drew on situations from my working life and discuss these with references that highlight the importance of involving different forms of knowledge, phenomenology and hermeneutics. I used the concept of genius loci to formulate the meaning of places and posthumanist thoughts on the relationship between humans and nature. My conclusion is that experience, reflection and knowledge of a place are central to building sites, a task in which the gardener is highly involved. I conclude with a number of questions about how to work with these aspects of the profession in education and working life

Litterär storyline som bidrag till interkulturell pedagogik

Det övergripande syftet med studien är att analysera hur litterär storyline fungerar som metod för interkulturell litteraturpedagogik. Jag har designat en litterär storyline som två lärare i årskurs 7 har genomfört i två klasser i en finlandssvensk skola. Storylinen utgår från boken En ö i havet (1996) av Annika Thor och handlar om två österrikiska judiska syskon som av sina föräldrar sänds till Sverige för att undkomma judeförföljelsen under andra världskriget. Boken, vars överordnade tema är kulturmöten, erbjuder en bearbetning av mångdimensionella existentiella livsfrågor. Fältstudien präglas av en etnografisk metodisk ansats med aktionsinriktning. Min forskarroll i klassrummet är en passiv observatör där jag gör temporära interventioner under pågående projekt. Studien betraktas dels ur ett litteraturpedagogiskt perspektiv, dels ur ett kritiskt mångkulturellt pedagogiskt perspektiv där interkulturell förståelse är centralt. Eleverna har individuellt och kollektivt arbetat inom olika genrer med så kallade nyckelfrågor som rör flyktingar, kulturell tillhörighet och möten i fiktionen och i deras egna liv. Deras produktion analyseras genom receptionsanalys och meningskoncentrering. Studien bidrar till ny kunskap inom tre områden: det kunskapsmässiga, det metodologiska och det didaktiska området. För det första gäller kunskapsbidraget elevers förståelse av en historisk och aktuell samhällsproblematik i en finlandssvensk skolkontext. För det andra är kombinationen av receptionsanalys av litterär storyline och en teoristyrd analys och tolkning av ett digert material ett innovativt metodologiskt bidrag. Till detta fogas dessutom ett litteraturpedagogiskt perspektiv och en presentation av kritisk mångkulturell pedagogisk teori. För det tredje bidrar studien till utveckling av en didaktik där litteraturpedagogiska redskap och interkulturellt pedagogiskt tänkande skapat en gränsöverskridande didaktisk design med stor potential för djuplärande i förhållande till existentiella frågor i unga människors liv. Eleverna visar i olika grad förstärkt medvetande och kritiskt engagemang angående tematiken i Annika Thors bok. Hos merparten framgår en öppen attityd till andra etniciteter och människor som är annorlunda än dem själva. De har dock alltjämt fördomar och etnocentriska och stereotypa uppfattningar. Men de uttrycker också en antydan till förståelse av och empati för krigsbarnen och judarna under andra världskriget både i fiktionen och i verkligheten. I viss mån visar de tendenser till förståelse av och empati för dagens flyktingar. För att optimera litterär storyline som interkulturell pedagogisk metod krävs en utförlig kritisk reflektion och granskning av elevernas värderingar i helklass. Detta förutsätter stor kompetens av läraren, varför utbildning i kritisk mångkulturell pedagogik behövs. Nyckelord: Litteraturpedagogik, kritisk mångkulturell pedagogik, storyline, kulturell mångfald, kulturella minoriteterThe overriding purpose of the study is to analyze how book-based storyline works as a method for intercultural literature education. I have designed a book-based storyline which two seventh grade teachers have carried out in two classes in a Finland-Swedish school. The storyline is based on the novel En ö i havet/Faraway Island (1996/2009) by Annika Thor, and is about two Austrian Jewish siblings who are evacuated and sent to Sweden by their parents, in order to escape antisemitic perse¬cution during World War II. The book’s dominant theme is cultural encoun¬ters, and it deals with multifaceted existential questions. The field study is characterized by an action-oriented, ethnographic methodological approach. As a researcher, my role in the classroom is a passive, observatory one, but I intervene occasionally during work in progress. The study is conducted partly from a literature education theory perspective, and partly from a multicultural education perspective, in which intercultural understand¬ing is of central significance. The participating pupils work within different genres, both individually and collectively, with so-called key questions regarding refugees, cultural affiliations, and interpersonal encounters, both in the fiction and in their own lives. The work they produce is analyzed using reception analysis and sentence concentration. The study’s contribution to the acquisition of new knowledge can be described within three areas: a contribution to new knowledge, a methodological contribution and a contribution to didactics. Firstly, it offers a contribution to new knowledge with regard to pupils’ understanding of challenging social issues, both historical and current, in a Finland-Swedish school context. Secondly, the combination of recep¬tion analysis through a book-based storyline project, and a theory-driven analysis and interpretation of a substantial body of material, is an innovative methodological contribution, which combines literature education perspectives with critical multi¬cultural education theory. Thirdly, the study contributes to the development of di¬dactic methods, in which literature education tools and intercultural education thinking have created an interdisciplinary didactic design with considerable poten¬tial for in-depth learning in relation to existential questions in young people’s lives. The participating pupils display a heightened awareness and critical involvement in the book’s themes, to varying degrees. They nonetheless still have prejudices and ethnocentric, stereotypical views. However, they also express some indications of under¬standing and empathy for the children of war and the Jews during World War II, both in the fiction and in reality. To some extent, they display notions of under¬standing and empathy towards today’s refugees. An open attitude towards various ethnicities and people different from themselves emerges from the majority. In order to optimize book-based storyline as an intercultural education method, extensive critical reflection and examination of pupils’ values is necessary. This requires a high level of competence from the teacher, which is why competence development in the field of critical multicultural education is needed. Keywords: Literature education, critical multicultural education, storyline, cultural diversity, cultural minoritie