| 491. |
- Jonsson, Bengt-Harald, et al.
(författare)
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Perspectives on the Classical Enzyme Carbonic Anhydrase and the Search for Inhibitors
- 2020
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Ingår i: Biophysical Journal. - : Elsevier BV. - 0006-3495 .- 1542-0086. ; 119:7, s. 1275-1280
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Forskningsöversikt (refereegranskat)abstract
- Carbonic anhydrase (CA) is a thoroughly studied enzyme. Its primary role is the rapid interconversion of carbon dioxide and bicarbonate in the cells, where carbon dioxide is produced, and in the lungs, where it is released from the blood. At the same time, it regulates pH homeostasis. The inhibitory function of sulfonamides on CA was discovered some 80 years ago. There are numerous physiological-therapeutic conditions in which inhibitors of carbonic anhydrase have a positive effect, such as glaucoma, or act as diuretics. With the realization that several isoenzymes of carbonic anhydrase are associated with the development of several types of cancer, such as brain and breast cancer, the development of inhibitor drugs specific to those enzyme forms has exploded. We would like to highlight the breadth of research on the enzyme as well as draw the attention to some problems in recent published work on inhibitor discovery.
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| 492. |
- Jonsson, Bertil, 1956-
(författare)
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Interaction between humans and car seats : studies of occupant seat adjustment, posture, position, and real world neck injuries in rear-end impacts
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: The latest generation of rear-end whiplash protection systems, as found in the WHIPS Volvo and SAHR Saab, have reduced injury rates by almost 50% in comparison with the previous generation of seat/head restraint systems. Occupant behaviour, such as seated posture and seat adjustment settings, may affect the injury risk. Method: Five studies were conducted. Studie I was an injury outcome study based on insurance data. Studies II-IV investigated seat adjustment, occupant backset, and cervical retraction for drivers and occupants in different postures and positions in the car, during stationary and driving conditions. Study V compared the occupant data from studies II and III with a vehicle testing tool, the BioRID dummy, using the protocols of the ISO, RCAR, and the RCAR-IIWPG. Results: Female drivers and passengers had a threefold increased risk for medically-impairing neck injury in rear-end impacts, compared to males. Driver position had a double risk compared with front passenger seat position. Female drivers adjusted the driver seat differently to male drivers; they sat higher and closer to the steering wheel and with more upright back support. The volunteers also adjusted their seat differently to the ISO, RCAR, and RCAR-IIWPG protocol settings; both sexes sat further away from the steering wheel, and seat back angle was more upright then in the protocols. In stationary cars, backset was highest in the rear seat position and lowest in the front passenger seat position. Males had a larger backset than females. Cervical retraction decreased and backset increased for both sexes when posture changed from self-selected posture to a slouched posture. The BioRID II dummy was found to represent 96th percentile female in stature, and a 69th percentile female in weight in the volunteer group. Conclusions: Risks in car rear-end impacts differ by sex and seated position. This thesis indicates the need for a 50th percentile female BioRID dummy and re-evaluation of the ISO, RCAR, and RCAR-IIWPG protocols, and further development of new safety systems to protect occupants in rear-end impacts.
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| 493. |
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| 494. |
- Jonsson, Carin, 1950-
(författare)
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Läsningens och skrivandets bilder : en analys av villkor och möjligheter för barns läs- och skrivutveckling
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The child who starts school soon becomes aware that it is important to learn to read and write. When it is educated in written literacy, pictures are used in reading textbooks and other school materials. The child is also asked to draw and talk about pictures in other contexts. Against this background, the aim of the study is to investigate the importance of pictures for children’s learning to read and write. The aim includes a description and analysis of the existing reading and writing discourse. The study problemises relational aspects of school practice, research and teacher education. This problemisation visualises a need for both a change and a development of the field of reading and writing. The thesis starts with a knowledge survey of the field of reading and writing. The survey provides the basis of a text study in which 11 Swedish theses, published between 1996 and 2003, are discussed and related to report materials published by The Swedish National Agency for School Improvement and the Board of Education. The text study is followed by an analysis of pictures, where the empirical material consists both of pictures taken from reading textbooks and reading diagnoses and pictures produced by children. The total result shows that there is consensus about the importance of different methods being applied through balanced reading programmes. At the same time it seems as if the field includes two discourses, a reading and a writing discourse. The dominant reading discourse is characterised by a strong emphasis on the teacher’s competence in terms of being able to see, create progression, arrange in order, settle up and correct for the purpose of providing good preconditions for learning. Pictures are given here a clearly subordinate role. As for the writing discourse, there is a clear shift from the teacher to the child as a meaning carrying and meaning creating subject. To some extent pictures are then recognised as a complementary form of mediation in connection with writing. In the reading discourse it is clear that pictures are traditionally used as illustrations of texts for the purpose of proficiency training. In that case pictures are given a complex role. On the one hand they are criticised for being ambiguous. This ambiguity can lead the child away from effective decoding. On the other hand it is presupposed, paradoxically enough, that there is a one-to-one relationship between picture and text. In contrast, children themselves seem to be able to apply a well-integrated use of picture and text where the intention is superordinate to the convention. The picture-text relation is then expansive: through the child’s involvement the interplay between words and pictures is functional and creates meaning. The thesis shows that a widened text concept, and consideration for the forms of production and presentation that characterise our culture, may yield knowledge contributing to developing the field of reading and writing. In order for this development to be possible, a complementary description of what characterises the respective discourse is required. In this description the concepts of communication and language, society and context and understanding and action function as an active intertriad for handling the teaching of reading and writing not as two separate fields but as a broadened, and at the same genuinely inclusive, field of knowledge.
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| 495. |
- Jonsson Čabrajić, Anna V, 1978-
(författare)
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Modeling lichen performance in relation to climate : scaling from thalli to landscapes
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Lichens can colonize nearly all terrestrial habitats on earth and are functionally important in many ecosystems. Being poikilohydric, their active growth periods are restricted to periods when the thallus is hydrated from atmospheric water sources, such as rain, fog and high relative humidity. Since lichen hydration varies greatly over time lichen growth is therefore more difficult to model compared with, for example vascular plants with more even water supply. I developed two models to predict lichen hydration under field conditions that incorporates the atmospheric water potential (Ψair), derived from air temperature and humidity, only or in combination with species-specific rehydration and desiccation rates. Using Ψair allows the prediction of hydration induced by several water sources. These models were very accurate for epiphytic lichens with a close coupling to atmospheric conditions, but they were less accurate for mat-forming lichens with substantial aerodynamic boundary layers. The hydration model was further developed to include photosynthetic activation for different species, in order to compare their performance under different micro-climatic scenarios. Water balance and activation rate had large effects on lichen activity and were positively related to habitats providing long hydration periods, for example close to streams. To study effects of climate change, a complete model for net carbon gain (photosynthesis minus respiratory losses) was developed for an epiphytic lichen with intricate responses to light, hydration and temperature. Simulation responses in different climate scenarios revealed that projected climate change on a regional scale resulted in varied local scale responses. At the lighter, exposed sites of a forest, the growth responses were positive, but were potentially negative at darker sites with closed canopy. At the local scale, fluctuating hydration, summed irradiance when wet and Chlorophyll a are variables that predict lichen growth. However, at a landscape scale, these variables may be too detailed. We tested this for two terrestrial, mat-forming lichens and developed statistical models for lichen growth in the widest possible climatic gradient in northern Scandinavia, varying in light, temperature and precipitation. Light was the most important factor for high growth at the landscape scale, reaching saturation at a site openness of 40 %, equivalent to a basal tree area of 15 m2 ha -1 in this study. Thereafter, hydration was the next limiting factor, which could be well described by precipitation for one of the species. The simplest predictor was the normal temperature in July, which was negatively correlated with growth. It was apparent that the predictive variables and their power varied at different scales. However, light and hydration are limiting at all scales, particularly by light conditions when lichens are wet. This implies that ensuring that there is sufficient light below the forest canopy is crucial for lichen growth, especially for mat-forming lichens. Hydrophilic lichens may be better preserved in open habitats with long hydration periods. It was shown that models can be powerful and “easy to use” tools to predict lichen responses in various habitats and under different climate scenarios. Models can therefore help to identify suitable habitats with optimal growth conditions, which is very important for the conservation and management of lichens and their habitats.
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| 496. |
- Jonsson, Daniel, et al.
(författare)
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Reconciling user benefit and time-geography-based individual accessibility measures
- 2014
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Ingår i: Environment and Planning, B. - : Sage Publications. - 0265-8135 .- 1472-3417. ; 41:6, s. 1031-1043
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a dynamic discrete choice model of activity scheduling that features classic time-geography properties within a microeconomic framework. We present results that show how the model can produce accessibilities that form space-time prisms, while retaining the properties of traditional measures based on consumer surplus in the form of logsums. The main features of the model are that it handles time-space constraints, travel time uncertainty, and endogenous trip chaining in one consistent framework. The resulting accessibility respects the individual's time budget and fixed activities. The dynamic discrete choice framework makes possible estimation of behavioural parameters using well-known methods. Some of the remaining computational challenges are discussed. The final section provides some examples of the policy analysis possibilities provided by a model of this kind.
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| 497. |
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| 498. |
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| 499. |
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| 500. |
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