| 1. |
- Laurén, Ari, et al.
(författare)
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Nitrogen and Carbon Dynamics and the Role of Enchytraeid Worms in Decomposition of L, F and H Layers of Boreal Mor
- 2012
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Ingår i: Water, Air and Soil Pollution. - : Springer Science and Business Media LLC. - 0049-6979 .- 1573-2932. ; 223:7, s. 3701-3719
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Tidskriftsartikel (refereegranskat)abstract
- Decomposition of organic material releases carbon dioxide (CO2) into the atmosphere, and dissolved organic carbon (DOC), dissolved organic nitrogen (DON) and ammonium (NH4-N) into soil water. Each of the decomposition products contributes differently to overall export of carbon (C) and nitrogen (N) to water courses. Our aim was to study the quantity and composition of the released C and N as affected by the organic material and soil fauna, represented by enchytraeid worms. We measured the release rate of carbon dioxide, and calculated the release rates for DOC and dissolved N in soil from repeated measurements of DOC and N pools during laboratory incubation of litter (L), fermented (F) and humus (H) layers of boreal forest mor. The intermediate decomposition products, DOC and DON, were characterised according to the molecule size. The release rate of the decomposition products was higher for fresh than for old organic material. The majority of N and C were released as NH4-N and CO2, respectively. The amount of extractable organic N in soil decreased by time but DON increased. Enchytraeids stimulated N mineralisation and the release of large molecule size DOC, particularly in L layer. The results suggest that organic N in extractable form biodegrades effectively, and that soil fauna have an important role in the decomposition. The results were interpreted from the water quality point of view and the implications of the results to modelling of decomposition and export of DOC and dissolved N to recipient water bodies are discussed. In the modelling context, the novelty of the study is the description of the intermediate decomposition products and the division of the dissolved organic compounds into low molecular weight and high molecular weight fractions.
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| 2. |
- Linna, Petri, et al.
(författare)
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Assessment of social media skills among vocational teachers in Finland
- 2015
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Ingår i: EDULEARN 15. - Valencia, Spain : The International Academy of Technology, Education and Development. - 9788460682431 ; , s. 4574-4581
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Konferensbidrag (refereegranskat)abstract
- Information technology penetration in the automotive industry has forced education in upper secondary vocational teaching to radically change. In car mechanic training this has an influence on traditional teaching methods as well as upon the substance of the education. At the same time education is generally changing to use social media (SOME) tools in various novel pedagogical settings. SOME may be seen as one solution to the challenges to the automotive sector. However, teachers need to be motivated to enter into a new era of education. In this case study we explore the upper secondary vocational teachers' ability to utilize SOME in teaching. We planned, tested and verified an assessment tool for evaluating SOME skills among vocational teachers. We also planned and provided training for vocational teachers in the use of SOME tools. Our findings were that the ability to utilize SOME tools among vocational teachers was not good and teachers were surprisingly conservative towards new educational technology. We discovered that utilizing an assessment survey questionnaire before and feedback questionnaire afterwards, greatly benefited a training course by plugging existing knowledge gaps and planning the training accordingly.
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| 3. |
- Palmolahti, Lauri, et al.
(författare)
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Pinhole-resistant nanocrystalline rutile TiO2 photoelectrode coatings
- 2022
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Ingår i: Acta Materialia. - : Elsevier BV. - 1359-6454. ; 239
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Tidskriftsartikel (refereegranskat)abstract
- Atomic layer deposited (ALD) TiO2 thin films have a wide range of applications in photonics which are, however, limited by the chemical instability of the amorphous as-deposited TiO2. Post-deposition annealing is required for improving the performance by inducing phase transitions and oxide defects. ALD precursor traces remaining in the TiO2 film affect the thermally-induced processes but the understanding of the effect of growth temperature on precursor traces in the film as well as on the thermally-induced processes is weak. In this study 30 nm ALD TiO2 was grown on Si wafer from tetrakis(dimethylamido)titanium and water at 100–200 °C. TiO2 was subsequently annealed in vacuum at 200–500 °C. Increasing the growth temperature decreased the amount of N bearing precursor traces and thus makes the TiO2 more easily reducible. The reduction takes place simultaneously with the crystallization and formation of O1− defects. Vacuum annealing of TiO2 with less than 0.3 at% of N results in nanocrystalline rutile whereas samples with more N containing traces crystallized as microcrystalline anatase. Nanocrystalline rutile TiO2 was chemically stable and resistant to the dissolution at the grain boundaries under alkaline conditions making it a suitable material for protective photoelectrode coatings used in artificial photosynthesis.
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| 4. |
- Remes, Tiina Maria, et al.
(författare)
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Radiation-induced accelerated aging of the brain vasculature in young adult survivors of childhood brain tumors
- 2020
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Ingår i: Neuro-Oncology Practice. - : Oxford University Press (OUP). - 2054-2577 .- 2054-2585. ; 7:4, s. 415-427
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundCranial radiotherapy may damage the cerebral vasculature. The aim of this study was to understand the prevalence and risk factors of cerebrovascular disease (CVD) and white matter hyperintensities (WMHs) in childhood brain tumors (CBT) survivors treated with radiotherapy.MethodsSeventy CBT survivors who received radiotherapy were enrolled in a cross-sectional study at a median 20 years after radiotherapy cessation. The prevalence of and risk factors for CVD were investigated using MRI, MRA, and laboratory testing. Tumors, their treatment, and stroke-related data were retrieved from patients’ files.ResultsForty-four individuals (63%) had CVD at a median age of 27 years (range, 16-43 years). The prevalence rates at 20 years for CVD, small-vessel disease, and large-vessel disease were 52%, 38%, and 16%, respectively. Ischemic infarcts were diagnosed in 6 survivors, and cerebral hemorrhage in 2. Lacunar infarcts were present in 7, periventricular or deep WMHs in 34 (49%), and mineralizing microangiopathy in 21 (30%) survivors. Multiple pathologies were detected in 44% of the participants, and most lesions were located in a high-dose radiation area. Higher blood pressure was associated with CVD and a presence of WMHs. Higher cholesterol levels increased the risk of ischemic infarcts and WMHs, and lower levels of high-density lipoprotein and higher waist circumference increased the risk of lacunar infarcts.ConclusionsTreating CBTs with radiotherapy increases the risk of early CVD and WMHs in young adult survivors. These results suggest an urgent need for investigating CVD prevention in CBT patients.
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| 5. |
- Saari, Jesse, et al.
(författare)
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Tunable Ti 3+ -Mediated Charge Carrier Dynamics of Atomic Layer Deposition-Grown Amorphous TiO 2
- 2022
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Ingår i: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 126:9, s. 4542-4554
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Tidskriftsartikel (refereegranskat)abstract
- Amorphous titania (am.-TiO2) has gained wide interest in the field of photocatalysis, thanks to exceptional disorder-mediated optical and electrical properties compared to crystalline TiO2. Here, we study the effects of intrinsic Ti3+ and nitrogen defects in am.-TiO2 thin films via the atomic layer deposition (ALD) chemistry of tetrakis(dimethylamido)titanium(IV) (TDMAT) and H2O precursors at growth temperatures of 100-200 °C. X-ray photoelectron spectroscopy (XPS) and computational analysis allow us to identify structural disorder-induced penta- and heptacoordinated Ti4+ ions (Ti5/7c4+), which are related to the formation of Ti3+ defects in am.-TiO2. The Ti3+-rich ALD-grown am.-TiO2 has stoichiometric composition, which is explained by the formation of interstitial peroxo species with oxygen vacancies. The occupation of Ti3+ 3d in-gap states increases with the ALD growth temperature, inducing both visible-light absorption and electrical conductivity via the polaron hopping mechanism. At 200 °C, the in-gap states become fully occupied extending the lifetime of photoexcited charge carriers from the picosecond to the nanosecond time domain. Nitrogen traces from the TDMAT precursor had no effect on optical properties and only little on charge transfer properties. These results provide insights into the charge transfer properties of ALD-grown am.-TiO2 that are essential to the performance of protective photoelectrode coatings in photoelectrochemical solar fuel reactors.
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| 6. |
- Saari, Mika, et al.
(författare)
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Explorative Study Of Teaching Programming To Vocational Teachers In Finland
- 2015
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Ingår i: Edulearn 15. - Valencia, Spain : The International Academy of Technology, Education and Development. - 9788460682431 ; , s. 2860-2869
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Konferensbidrag (refereegranskat)abstract
- In this study we explore the possibility of organizing and structuring an information technology training day for upper secondary vocational teacher training in automotive and transport engineering. The objective is to show the development process of the three training sessions in response to survey data completed by teachers. Information technology has widely penetrated into the car industry during the last few decades but some teachers have difficulty in adapting and teaching new technologies to their students. This paper presents one approach to break the ice between 'old school' teachers and information technology, through the use of an 8-hour training day consisting of programming, electronic technology and data bus technology.The aim of this study is to discover how to structure training of new technology for experienced vocational teachers. In this paper we describe how we developed, organized and assessed information technology training for vocational teachers within the case study. The training day was organized in three locations in Finland: Pori, Jyvaskyla and Vantaa. After the first surveys were completed by the vocational teachers, the arrangement of the next training day was adjusted in response to the outcome of the initial surveys. After the first lecture session, the training feedback indicated that there should be more 'learning-by-doing' type of action. The next sessions included Arduino board [1], electronic components and a laptop software development environment.In this study we found that the attitudes of the training attendees were different in three locations around Finland. This is an interesting finding. When comparing the results obtained from Jyvaskyla and Vantaa the outcomes were slightly more negative in Jyvaskyla than in Vantaa. However the training was identical in both cases. The results also showed a difference in attitude between teachers of different age groups.One of the biggest problems in this type of training was the limitation of time. Most of the teachers were familiar with the automotive based digital testing equipment, but they were also aware that their students were far more advanced in information technology than they were. This may have generated tensions and resistance from the older generation of teacher when adopting any new technology.The overall outcome was positive. Teachers were pleased with this training in an automotive context, because it was first time they had received generic technological training. The attendees felt it was important because the training sessions were targeted directly to them. The collected survey results provided information about what vocational teachers are actually missing in practice. In the conceptual part of this paper we discuss motivation to learn [2,3] and adult education. In the empirical part of this paper we introduce the training method utilized and finally discuss the presented outcomes and conclusions of the survey data.
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