| 1. |
- Aidas, Kestutis, et al.
(författare)
-
The Dalton quantum chemistry program system
- 2014
-
Ingår i: WIREs Computational Molecular Science. - : Wiley. - 1759-0876 .- 1759-0884. ; 4:3, s. 269-284
-
Tidskriftsartikel (refereegranskat)abstract
- Dalton is a powerful general-purpose program system for the study of molecular electronic structure at the Hartree-Fock, Kohn-Sham, multiconfigurational self-consistent-field, MOller-Plesset, configuration-interaction, and coupled-cluster levels of theory. Apart from the total energy, a wide variety of molecular properties may be calculated using these electronic-structure models. Molecular gradients and Hessians are available for geometry optimizations, molecular dynamics, and vibrational studies, whereas magnetic resonance and optical activity can be studied in a gauge-origin-invariant manner. Frequency-dependent molecular properties can be calculated using linear, quadratic, and cubic response theory. A large number of singlet and triplet perturbation operators are available for the study of one-, two-, and three-photon processes. Environmental effects may be included using various dielectric-medium and quantum-mechanics/molecular-mechanics models. Large molecules may be studied using linear-scaling and massively parallel algorithms. Dalton is distributed at no cost from for a number of UNIX platforms.
|
|
| 2. |
|
|
| 3. |
- Barkar, Thomas, et al.
(författare)
-
Creep simulation of 9-12% Cr steels using the composite model with thermodynamically calculated input
- 2005
-
Ingår i: Materials Science & Engineering. - : Elsevier BV. - 0921-5093 .- 1873-4936. ; 395:1-2, s. 110-115
-
Tidskriftsartikel (refereegranskat)abstract
- Creep of 9-12% Cr steels is modeled using the composite model, developed by Blum et al. [R. Sedlacek, W. Blum, Comput. Mater. Sci. 25 (2002) 200], and thermodynamic calculations based on the Calphad approach. The composite model yields a physical description of the deformation behavior of materials that have a pronounced heterogeneous dislocation structure and is briefly surveyed. A few of the input parameters have been thermodynamically calculated using Thermo-Calc and introduced to the main program via a programming interface. This combined approach allows us to simulate the creep deformation behavior with less extensive microstructural investigations. This is a step towards enabling predictions of the creep behavior predominantly based on the nominal composition, heat treatment and mechanical load. Simulation results for two different 9-12% Cr steels are presented.
|
|
| 4. |
- Barkar, Thomas, et al.
(författare)
-
Effect of concentration dependent gradient energy coefficient on spinodal decomposition in the Fe-Cr system
- 2018
-
Ingår i: Computational materials science. - : Elsevier. - 0927-0256 .- 1879-0801. ; 143, s. 446-453
-
Tidskriftsartikel (refereegranskat)abstract
- The Cahn–Hilliard equation is solved with thermodynamic and kinetic input, using the Thermo-Calc and DICTRA software packages rather than simpler models e.g. regular solution. A concentration dependent expression for the gradient energy coefficient is introduced and its effect on simulated decomposition is discussed. Simulations were carried out in 2D and 3D using the FiPy software package modified for non-linear problems.
|
|
| 5. |
- Barkar, Thomas
(författare)
-
Modelling phase separation in Fe-Cr alloys : A continuum approach
- 2018
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The formation of Cr-rich and Fe-rich domains upon ageing of an initially homogeneous Fe-Cr alloy at elevated temperatures (300-600 ºC) is commonly referred to as phase separation. The behaviour originates from a miscibility gap in the Fe-Cr phase diagram. The boundary of the miscibility gap is denoted the binodal, and the line where the second derivative of the molar Gibbs energy w.r.t. composition is zero, the spinodal. In the region between the binodal and spinodal lines, the phase separation is said to occur by means of nucleation and growth. Inside the spinodal line, no thermally activated nucleation event is needed, and the initially homogeneous alloy decomposes "spinodally" into Cr-rich and Fe-rich regions. This type of phase transformation can be viewed as a continuous build up of Cr-rich regions, that also are interconnected, forming a microstructure characteristic for alloys decomposed spinodally. Phase separation has been of great interest within the metallurgical community as well as industry, due to its embritteling effect. Phase separation in Cr-rich ferritic steels, and thus embrittlement, sets a practical upper service temperature of ~300 ºC for Cr-containing ferrites. It is desirable to develop understanding and modelling capability for decomposing alloy systems, since such knowledge could be used to relieve the limitation in service temperature. The current work has been focused around the development and use of computer simulations, using thermodynamic and kinetic input from databases, in order to progress towards alloy design where decomposition is minimized. Simulations in this work are based on solving the so called Cahn-Hilliard equation, where an important parameter is the gradient energy, since it influences both the morphology and rate of decomposition in the simulations. An attempt at formulating a general model for the gradient energy coefficients in multi-component systems has been made, but has yet to be properly tried against experimental data. Improvements, and insights, to the initial state used in simulations has also been achieved. The combination of above mentioned efforts is a step towards a predictive tool for decomposition of complex alloys. Such a tool could not only be an aid in future alloy design, but also be used as an aid as a diagnosis tool in life time assessment of critical components already in use and thereby difficult to assess on site by means of in-destructive testing, typically components in nuclear power facilities.
|
|
| 6. |
- Barkar, Thomas, et al.
(författare)
-
Phase field modeling of spinodal decomposition in Fe-Cr based alloys
- 2015
-
Ingår i: PTM 2015 - Proceedings of the International Conference on Solid-Solid Phase Transformations in Inorganic Materials 2015. - : International Conference on Solid-Solid Phase Transformations in Inorganic Materials. - 9780692437360 ; , s. 827-828
-
Konferensbidrag (refereegranskat)
|
|
| 7. |
|
|
| 8. |
- Björkstrand, Johannes, et al.
(författare)
-
Decrease in amygdala activity during repeated exposure to spider images predicts avoidance behavior in spider fearful individuals.
- 2020
-
Ingår i: Translational Psychiatry. - : Springer Science and Business Media LLC. - 2158-3188. ; 10:1
-
Tidskriftsartikel (refereegranskat)abstract
- Spider phobia is characterized by exaggerated fear of situations where spiders could be present, resulting in avoidance of such situations and compromised quality of life. An important component in psychological treatment of spider phobia is exposure to phobic situations that reduces avoidance behaviors. At the neural level, amygdala responses to phobic material are elevated, but normalizes following exposure treatment. To what extent amygdala activity decreases during a session of repeated phobic stimulation, and whether activity decrease is related to subsequent avoidance is not well studied. We hypothesized reduced amygdala activity during the course of repeated exposure to spider pictures, and that the degree of reduction would predict subsequent avoidance of spider pictures. To test our hypothesis, functional magnetic resonance imaging was performed in 45 individuals with spider fear during repeated exposure to spider pictures. Results showed that repeated exposure to spider stimuli attenuated amygdala reactivity and individual differences in activity reductions predicted subsequent avoidance behavior to spider pictures in an incentive-conflict task, with larger attenuations predicting less avoidance. At 6-month follow up, initial reductions in amygdala activation still predicted avoidance. This result demonstrates that reduction in amygdala responses is related to clinically meaningful outcomes in human anxiety, and suggests that within-session reductions in amygdala responses could be an important mechanism explaining the clinical effects of exposure therapy.
|
|
| 9. |
- Björkstrand, Johannes, et al.
(författare)
-
Disrupting Reconsolidation Attenuates Long-Term Fear Memory in the Human Amygdala and Facilitates Approach Behavior
- 2016
-
Ingår i: Current Biology. - : Elsevier BV. - 0960-9822 .- 1879-0445. ; 26:19, s. 2690-95
-
Tidskriftsartikel (refereegranskat)abstract
- Memories become labile and malleable to modification when recalled [1]. Fear-conditioning experiments in both rodents and humans indicate that amygdala-localized short-term fear memories can be attenuated by disruption of their reconsolidation with extinction training soon after memory activation [2-7]. However, this may not be true for natural long-term fears. Studies in rodents indicate that although it is possible to disrupt the reconsolidation of older memories [8-11], they appear to be more resistant [1, 3, 9, 12, 13]. In humans, 1-week-old conditioned fear memories have been attenuated by behaviorally induced disruption of reconsolidation [14], but it remains to be seen whether this is possible for naturally occurring long-term fears and whether the underlying neural mechanisms are similar to those found in experimental fear-conditioning paradigms. Using functional brain imaging in individuals with a lifelong fear of spiders, we show that fear memory activation followed by repeated exposure to feared cues after 10 min, which disrupts reconsolidation, attenuates activity in the basolateral amygdala at re-exposure 24 hr later. In contrast, repeated exposure 6 hr after fear memory activation, which allows for reconsolidation, did not attenuate amygdala activity. Disrupted, but not undisrupted, reconsolidation facilitated approach behavior to feared cues, and approach behavior was inversely related to amygdala activity during re-exposure. We conclude that memory activation immediately preceding exposure attenuates the neural and behavioral expression of decades-old fear memories and that, similar to experimentally induced fear memories, the basolateral amygdala is crucially involved in this process.
|
|
| 10. |
|
|
| 11. |
- Björkstrand, Johannes, et al.
(författare)
-
Disruption of Memory Reconsolidation Erases a Fear Memory Trace in the Human Amygdala : An 18-Month Follow-Up.
- 2015
-
Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 10:7, s. e0129393-
-
Tidskriftsartikel (refereegranskat)abstract
- Fear memories can be attenuated by reactivation followed by disrupted reconsolidation. Using functional magnetic resonance imaging we recently showed that reactivation and reconsolidation of a conditioned fear memory trace in the basolateral amygdala predicts subsequent fear expression over two days, while reactivation followed by disrupted reconsolidation abolishes the memory trace and suppresses fear. In this follow-up study we demonstrate that the behavioral effect persists over 18 months reflected in superior reacquisition after undisrupted, as compared to disrupted reconsolidation, and that neural activity in the basolateral amygdala representing the initial fear memory predicts return of fear. We conclude that disrupting reconsolidation have long lasting behavioral effects and may permanently erase the fear component of an amygdala-dependent memory.
|
|
| 12. |
- Björkstrand, Johannes, et al.
(författare)
-
Think twice, it's all right : Long lasting effects of disrupted reconsolidation on brain and behavior in human long-term fear
- 2017
-
Ingår i: Behavioural Brain Research. - : Elsevier BV. - 0166-4328 .- 1872-7549. ; 324, s. 125-129
-
Tidskriftsartikel (refereegranskat)abstract
- Memories can be modified when recalled. Experimental fear conditioning studies support that amygdala-localized fear memories are attenuated when reconsolidation is disrupted through extinction training immediately following memory activation. Recently, using functional brain imaging in individuals with lifelong spider fears, we demonstrated that fear memory activation followed by repeated exposure to feared cues after 10 min, thereby disrupting reconsolidation, attenuated activity in the amygdala during later re-exposure, and also facilitated approach behavior to feared cues. In contrast, repeated exposure 6 h after fear memory activation, allowing for reconsolidation, did not attenuate amygdala activity and resulted in less approach behavior as compared to the group that received disrupted reconsolidation. We here evaluated if these effects are stable after 6 months and found that amygdala activity was further reduced in both groups, with a tendency towards greater reductions in the 10 min than the 6 h group. Hence, disrupted reconsolidation results in long lasting attenuation of amygdala activity. The behavioral effect, with more approach towards previously feared cues, in the 10 min than the 6 h group also persisted. Thus, the brain effect of disrupted reconsolidation is stable over 6 months and the behavioral effect also remained. We therefore conclude that disrupted reconsolidation result in a long-lasting diminished fear memory representation in the amygdala which may have clinical importance.
|
|
| 13. |
- Bonvalet-Rolland, Manon, et al.
(författare)
-
Kinetic theory of nucleation in multicomponent systems : An application of the thermodynamic extremum principle
- 2019
-
Ingår i: Acta Materialia. - : Acta Materialia Inc. - 1359-6454 .- 1873-2453. ; 171, s. 1-7
-
Tidskriftsartikel (refereegranskat)abstract
- Nucleation kinetics in a multicomponent supersaturated solid solution is examined. Attachment rate of atoms to a nucleus of a size close to the critical one is determined combining a thermodynamic extremum principle and the Fokker-Planck equation. Two limiting cases are examined; when bulk diffusion controls the nucleation kinetics and when the process is limited by the interfacial mobility. The mixed regime is also treated. Moreover, the growth law in multicomponent alloys is derived in the general case, when both mechanisms are considered. Additionally, the attachment rate is derived, in the classical framework, from a new macroscopic growth equations and the fundamental role of the interfacial mobility is examined. These new general expressions, for the attachment rates and the growth laws, determined either applying the thermodynamic extremum principle or derived from the classical formalism are found to be consistent.
|
|
| 14. |
- Boren, Jan, et al.
(författare)
-
The molecular mechanism for the genetic disorder familial defective apolipoprotein B100
- 2001
-
Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 276:12, s. 9214-9218
-
Tidskriftsartikel (refereegranskat)abstract
- Familial defective apolipoprotein B100 (FDB) is a genetic disorder in which low density lipoproteins (LDL) bind defectively to the LDL receptor, resulting in hypercholesterolemia and premature atherosclerosis. FDB is caused by a mutation (R3500Q) that changes the conformation of apolipoprotein (apo) B100 near the receptor-binding site. We previously showed that arginine, not simply a positive charge, at residue 3500 is essential for normal receptor binding and that the carboxyl terminus of apoB100 is necessary for mutations affecting arginine 3500 to disrupt LDL receptor binding. Thus, normal receptor binding involves an interaction between arginine 3500 and tryptophan 4369 in the carboxyl tail of apoB100. W4369Y LDL and R3500Q LDL isolated from transgenic mice had identically defective LDL binding and a higher affinity for the monoclonal antibody MB47, which has an epitope flanking residue 3500. We conclude that arginine 3500 interacts with tryptophan 4369 and facilitates the conformation of apoB100 required for normal receptor binding of LDL. From our findings, we developed a model that explains how the carboxyl terminus of apoB100 interacts with the backbone of apoB100 that enwraps the LDL particle. Our model also explains how all known ligand-defective mutations in apoB100, including a newly discovered R3480W mutation in apoB100, cause defective receptor binding.
|
|
| 15. |
- Borgqvist, Martin, 1980-, et al.
(författare)
-
Certifierad energikonsult livsmedelsbutiker
- 2017
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Denna förstudie har undersökt förutsättningarna för en frivillig, ej ackrediterad certifiering av energikonsulter för livsmedelsbutiker. Det långsiktiga målet är att butiker med hjälp av certifierade energikonsulter skall få effektiva och kvalitativa energikartläggningar som innefattar såväl fastighetens som verksamhetens energianvändning och hur de olika delarna kan samverka för största möjliga energieffektivisering.Det finns en mycket stor potential att spara energi i butiker. Dagens genomsnittsbutik kan minska sin energianvändning med en tredjedel. Idag finns också en ökad miljömedvetenhet hos svenska livsmedelsbutiker, och med ett större behov av kyld mat har energifrågorna fått en allt större betydelse. Medlemmar i BELIVS Innovationskluster har länge efterfrågat en certifiering av energikonsulter för livmedelsbutiker, som utgår ifrån beställarnas behov. Detta för att öka andelen butiker med låg energianvändning, säker drift och liten miljöpåverkan.Förstudiens resultat består av; identifierade behov ur ett beställarperspektiv, en kravspecifikation som beskriver certifieringens kompetenskrav, en beskrivning av hur en certifiering är tänkt att gå till, samt ett exempel på hur ett certifieringsprov kan se ut. Dessutom har fyra stycken testcertifieringar genomförts, där exempelprovet har testats av energikonsulter. Tanken är att förstudiens resultat skall kunna användas som underlag för att ta fram ett färdigt certifieringsprogram.Den generella slutsatsen från förstudien är att certifieringen av energikonsulter för livsmedelsbutiker är genomförbar, men beställarna behöver efterfråga certifieringen i sina upphandlingar av konsulter om denna skall slå på marknaden. Baserat på diskussioner med representanter från konsultsidan, bedömer projektgruppen att det finns ett intresse för certifieringen så länge beställarna kommer att efterfråga detta. Att få fler beställare bakom den föreslagna certifieringen är den viktigaste åtgärden i ett nästa steg.RISE har drivit projektet tillsammans med INCERT, ICA Fastigheter, Coop och Hållbar Miljö & Strategi. Projektgruppen har haft kontakt med Bergendahls och Axfood vilka har deltagit vid enstaka arbetsmöten.Finansiärer av förstudien är Energimyndigheten, INCERT, ICA Fastigheter, Coop samt Bergendahls.
|
|
| 16. |
|
|
| 17. |
- Ellis, Thomas James, et al.
(författare)
-
Life-history trade-offs and the genetic basis of fitness in Arabidopsis thaliana
- 2021
-
Ingår i: Molecular Ecology. - : John Wiley & Sons. - 0962-1083 .- 1365-294X. ; 30:12, s. 2846-2858
-
Tidskriftsartikel (refereegranskat)abstract
- Resources allocated to survival cannot be used to increase fecundity, but the extent to which this trade-off constrains adaptation depends on overall resource status. Adaptation to local environmental conditions may therefore entail the evolution of traits that increase the amount of resources available to individuals (their resource status or ‘condition’). We examined the relative contribution of trade-offs and increased condition to adaptive evolution in a recombinant inbred line population of Arabidopsis thaliana planted at the native sites of the parental ecotypes in Italy and Sweden in 2 years. We estimated genetic correlations among fitness components based on genotypic means and explored their causes with QTL mapping. The local ecotype produced more seeds per fruit than did the non-local ecotype, reflected in stronger adaptive differentiation than was previously shown based on survival and fruit number only. Genetic correlations between survival and overall fecundity, and between number of fruits and number of seeds per fruit, were positive, and there was little evidence of a trade-off between seed size and number. Quantitative trait loci for these traits tended to map to the same regions of the genome and showed positive pleiotropic effects. The results indicate that adaptive differentiation between the two focal populations largely reflects the evolution of increased ability to acquire resources in the local environment, rather than shifts in the relative allocation to different life-history traits. Differentiation both in phenology and in tolerance to cold is likely to contribute to the advantage of the local genotype at the two sites.
|
|
| 18. |
|
|
| 19. |
|
|
| 20. |
|
|
| 21. |
|
|
| 22. |
|
|
| 23. |
- Fredrikson, Mats, et al.
(författare)
-
Meta-Analytical Evidence for Segregating and Integrating Brain Activation to Symptom Provocation in Social Anxiety Disorder, Specific Phobia and Post Traumatic Stress Disorder
- 2011
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Background: In PTSD increased amygdala activity is found in parallel to decreased anterior cingulate activity and this imbalance relate to symptomatology. Consistently, in healthy controls enhanced vmPFC activity suppress fear conditioning and enhance extinction similar to reappraisal studies where dPFC activation supports emotional down regulation through amygdala attenuation. It is not established if phobic disorders display a similar pattern and if treatment induced changes affect “top-down” and/or “bottom-up” mechanisms. Methods: Using a meta-analytical approach, we review brain-imaging studies using symptom provocation in patients with specific or social phobia as well as PTSD to evaluate reactivity in the ACC and the amygdala and its correlation to symptomatology. Further, amygdala ACC connectivity and the effect of CBT will be covered. Results: Functional brain imaging studies reveal increased amygdala reactivity that is correlated with symptomatology across the anxiety disorders. In phobic patients enhanced ACC responsivity is observed. The correlation between symptomatology and prefrontal brain activity is consistently negative and ACC related in PTSD while in phobic patients the relation is positive and encompass prefrontal areas outside the ACC, particularly in SAD. Connectivity patterns suggest couplings between amygdala and PFC, limited to ACC in PTSD but not in phobic disorders. Finally, CBT-treatment is associated both with increased and decreased activity in the ACC and other prefrontal areas. Conclusions: A tentative conclusion is that, even though the pattern of activity and connectivity both segregate and integrate different anxiety disorders, the ACC has a prominent role in coding and controlling affect.
|
|
| 24. |
- Frenkel, Martin, et al.
(författare)
-
Improper excess light energy dissipation in Arabidopsis results in a metabolic reprogramming
- 2009
-
Ingår i: BMC Plant Biology. - : Springer Science and Business Media LLC. - 1471-2229. ; 9:12, s. 1-16
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Plant performance is affected by the level of expression of PsbS, a key photoprotective protein involved in the process of feedback de-excitation (FDE), or the qE component of non-photochemical quenching, NPQ. Results: In studies presented here, under constant laboratory conditions the metabolite profiles of leaves of wild-type Arabidopsis thaliana and plants lacking or overexpressing PsbS were very similar, but under natural conditions their differences in levels of PsbS expression were associated with major changes in metabolite profiles. Some carbohydrates and amino acids differed ten-fold in abundance between PsbS-lacking mutants and over-expressers, with wild-type plants having intermediate amounts, showing that a metabolic shift had occurred. The transcriptomes of the genotypes also varied under field conditions, and the genes induced in plants lacking PsbS were similar to those reportedly induced in plants exposed to ozone stress or treated with methyl jasmonate (MeJA). Genes involved in the biosynthesis of JA were up-regulated, and enzymes involved in this pathway accumulated. JA levels in the undamaged leaves of field-grown plants did not differ between wild-type and PsbS-lacking mutants, but they were higher in the mutants when they were exposed to herbivory. Conclusion: These findings suggest that lack of FDE results in increased photooxidative stress in the chloroplasts of Arabidopsis plants grown in the field, which elicits a response at the transcriptome level, causing a redirection of metabolism from growth towards defence that resembles a MeJA/JA response.
|
|
| 25. |
|
|
| 26. |
|
|
| 27. |
- Frick, Andreas, et al.
(författare)
-
Enlargement of visual processing regions in social anxiety disorder is related to symptom severity
- 2014
-
Ingår i: Neuroscience Letters. - : Elsevier BV. - 0304-3940 .- 1872-7972. ; 583, s. 114-119
-
Tidskriftsartikel (refereegranskat)abstract
- Social anxiety disorder (SAD) is associated with altered brain function and structure, but most structural studies include small samples and findings are mixed. This study compared regional gray matter volume between 48 SAD patients and 29 healthy controls (HC) as well as the relationship between volume and symptom severity. Structural magnetic resonance images from SAD patients and HC were evaluated using standard voxel-based morphometry (VBM) processing in the SPM8 software package. Social anxiety symptom severity was rated in SAD patients by a clinician using the Liebowitz Social Anxiety Scale (LSAS). SAD patients had greater regional gray matter volume in the lingual gyrus and lateral occipital cortex than the controls, and within the SAD group a positive correlation was found between symptom severity and regional gray matter volume in the lingual gyrus and the retrosplenial cortex. These findings replicate and extend earlier reports of enlarged visual processing areas in SAD. Increased gray matter volume in regions involved in visual processing and self-consciousness could underlie, or be the result of, abnormal emotional information processing and self-focused attention previously demonstrated in patients with SAD.
|
|
| 28. |
- Granfeldt, Jonas, et al.
(författare)
-
Le rôle de l’input pour le développement du vocabulaire et de la grammaire en acquisition du français par des enfants monolingues et bilingues
- 2019
-
Konferensbidrag (refereegranskat)abstract
- Entre 2009 et 2011 nous avons mené un projet de recherche à l’université de Lund (Suède) intitulé L'âge de début d’acquisition et le développement linguistique en français (Schlyter/Granfeldt) dont le but était de comparer le développement linguistique du français de trois groupes d’enfants : des enfants monolingues (L1), des enfants bilingues simultanés (2L1) et des enfants ayant le français comme langue seconde (bilingues successifs, eL2). Nous avons notamment étudié les effets respectifs de l'âge de début d'acquisition (angl. Age of Onset of Acquisition), de la quantité et qualité de l'input ainsi que de la complexité linguistique sur le développement de la morphosyntaxe. Dans le cadre de cette étude nous nous étions concentré sur le développement d’un certain nombre de structures morphosyntaxiques (la finitude morphologique, les objets clitiques, l’accord sujet-verbe, le genre) que nous avions déjà étudié chez l’apprenant adulte L2 (Granfeldt, 2003; Ågren, 2008; Thomas, 2009) et chez les enfants L1 et 2L1 (Schlyter, 2003, Granfeldt, 2003, Granfeldt & Schlyter, 2004). Dans l’ensemble, les résultats ont montré que pour les structures morphosyntaxiques simples et (très) précoces en L1, le développement initial en eL2 suivait les itinéraires d’acquisition des apprenants aL2, même chez les eL2 dont l'âge de début d'acquisition se situe avant 4 ans. En revanche, pour les structures complexes et tardives en L1, nous avons plutôt observé le même développement en (2)L1 et en eL2 ainsi qu'une plus grande importance de l'input (Ågren, Granfeldt & Thomas, 2014). Une conclusion centrale de cette partie du projet est alors qu’au niveau des itinéraires d’acquisition, les structures morphosyntaxiques de français ne sont pas toutes pareilles : certaines sembleraient plus dépendantes de l’âge de début d’acquisition (finitude, placement des objets clitiques) alors que d’autres (attribution du genre, accord-sujet verbe) montrent de meilleures corrélations avec la quantité et de la qualité de l’input. Dans cette communication nous reviendrons sur un certain nombre de résultats dans le domaine du développement grammatical (Ågren, Granfeldt & Thomas, 2014) pour ensuite les comparer au développement de la richesse et de la précision du vocabulaire chez les mêmes enfants. La question est de savoir s’il existe une relation entre le développement du vocabulaire et de la morphosyntaxe, une question qui se pose depuis les origines des recherches systématiques en acquisition (cf. Brown, 1973). Dans une approche chomskyenne classique (principe et paramètres/gouvernement et liage) la syntaxe et le lexique sont des modules distincts alors que dans sa version récente (Minimalisme, Chomsky, 1995), Chomsky attribue les différences syntaxiques entre les langues aux propriétés du lexique, ce qui a eu des conséquences pour les théories d’acquisition ancrées dans cette perspective (cf. Granfeldt, 2003). Dans cette optique, les itinéraires développementaux sont facteurs de l’âge du début d’acquisition. Par contre, dans une approche basée sur l’usage de la langue (N. Ellis, 2002, Bybee, 2008) l’acquisition d’une langue est étroitement liée aux caractéristiques de l’input langagier ainsi qu’au traitement cognitif de celui-ci, et conçoit la relation entre lexique et grammaire comme un continuum. Dans le but de mieux comprendre la possible interdépendance entre lexique et morphosyntaxe, il nous faut plus d’études empiriques, qui, comme nous le proposons ici, combinent l’étude du développement lexical et morphosyntaxique avec différents types d’apprenant·e·s ayant différentes situations d’input. Pour les enfants L1 et 2L1, les recherches antérieures ont montré qu’il y a un effet d’input sur l’acquisition du vocabulaire (Pearsson et al., 1997, Thordardottir, 2011), mais peu de recherches ont fait ce que nous proposons ici, à savoir comparer les effets longitudinaux de la quantité et de la qualité de l’input sur le développement du vocabulaire et de la grammaire chez différents groupes d’enfants francophones (L1, 2L1 et eL2). Vu les résultats antérieurs, notre hypothèse est qu’il doit y avoir une corrélation entre le développement des structures grammaticales qui se sont avérées surtout dépendantes de l’input et le développement du vocabulaire. Les données de production proviennent d’un corpus longitudinal d’enfants francophones bilingues successifs (eL2, n=3), d’enfants bilingues simultanés (2L1, n=3) et d'enfants monolingues (L1, n=3), tous allant à la même école française en Suède. Les enfants ont été suivi pendant près de trois ans avec des enregistrements à des intervalles réguliers. L’analyse sera basée sur des tâches de production élicitée et des enregistrements de conversations libres avec les enfants. La notion de quantité et de qualité de l’input sera opérationnalisée pour chaque enfants à l’aide de profils d’input individuels et le vocabulaire Résumé pour le XXIXe Congrès International de Linguistique et de Philologie Romanes (Copenhague, 2019) Granfeldt, Ågren & Thomas sera mesuré à la fois quantitativement (la diversité du vocabulaire, VocD, Malvern et al., 2004) et qualitativement (la précision du vocabulaire). La présente étude sera centrée sur les questions de recherche suivantes : 1) La richesse du vocabulaire, mesurée par la diversité lexicale (VocD), diffère-t-elle entre enfants L1, 2L1 et eL2 de notre corpus ? 2) La richesse du vocabulaire (VocD) augmente-t-elle avec la durée d’exposition à la langue ? 3) L’effet de la quantité et de la qualité de l’input (mesuré par un profil d’input) est-il le même sur le développement du vocabulaire que sur le développement des structures grammaticales étudiées auparavant ? Y-a-t-il des différences entre les trois groupes d’enfants ? Les résultats montrent que les trois groupes d’enfants diffèrent au niveau de la diversité lexicale : les enfants L1 se distinguent de façon significative des enfants 2L1 qui, à leur tour, se distinguent des enfants eL2. Au niveau des groupes, un profil d’input plus fort semble donc se refléter en une diversité lexicale plus riche. Pourtant, nos analyses montrent que l’ampleur de la différence en termes de diversité lexicale entre groupes semble plus faible en vocabulaire qu’en grammaire (e.g. l’accord sujet-verbe). Autrement dit, l’effet de l’input pourrait être plus grand sur le vocabulaire que sur la structure syntaxique la plus susceptible d’être influencée par la quantité et la qualité d’input. En outre, contrairement à ce qui a été observé pour le développement grammatical, nous n’avons pas trouvé de corrélation entre le développement longitudinal des scores de diversité lexicale des enfants 2L1 et eL2 et leurs profils d’input. Il s’avère que le développement lexical, tel qu’il a été mesuré dans cette étude, n’évolue pas chez les trois enfants 2L1 alors que les enfants L2 ne montrent que de faibles signes de développement dans le domaine du vocabulaire. Ces observations seront discutées à la lumière des limitations possibles des mesures générales comme le VocD. Une analyse qualitative de la précision lexicale montre que les enfants eL2, et à un moindre degré les enfants 2L1, ont plus souvent recours à des verbes « passe-partout » (General Purpose Verbs, GAP, Harley, 1992) que les enfants L1, comme le montre les productions d’enfants dans un contexte qui ciblait la construction « emballer le cadeau » : (1) L1 Lina « ils l’emballent le cadeau… » (2) 2L1 Linnéa « ils commencent à faire le cadeau » (3) eL2 Hannes « après ils font le paquet pour l’anniversaire » Nous montrerons que les stratégies utilisées par les enfants 2L1 et eL2, notamment l’évitement, la paraphrase, la généralisation, jouent un rôle important dans le développement du vocabulaire. Le choix de la section Acquisition, apprentissage et enseignement des langues nous semble la plus pertinente pour cette communication. Avec notre accent sur la quantité et la qualité d’input, la proposition s’aligne bien avec des question sur « la complexion des variables interagissant dans l’apprentissage-enseignement des langues secondes et étrangères romanes ». Notre proposition est innovatrice puisqu’il existe peu d’études qui combinent le développement du lexique et de la morphosyntaxe dans une perspective longitudinale. Ensuite, les données sur l’acquisition du français par des enfants L2 sont très rares parmi les études récentes sur l’acquisition. Résumé pour le XXIXe Congrès International de Linguistique et de Philologie Romanes (Copenhague, 2019) Granfeldt, Ågren & Thomas Bibliographie ÅGREN, M. (2008). A la recherche de la morphologie silencieuse. Étude sur le développement du pluriel en français L2 écrit. Études Romanes de Lund 84. Thèse de doctorat, Université de Lund. ÅGREN, M., GRANFELDT, J. & THOMAS, A. (2014). Combined effects of age of onset and input on the development of different grammatical structures: A study of simultaneous and successive acquisition of French. Linguistic Approaches to Bilingualism, 4, 461-492. John Benjamins. BROWN, R. (1973). A first language: The early stages. Cambridge (MA): Harvard University Press. BYBEE, J. (2008). Usage-based grammar and second language acquisition. Dans P. Robinson & N. Ellis (éds.), Handbook of cognitive linguistics and second language acquisition. London: Routledge (216-236). CHOMSKY, N. (1995). The minimalist program. Cambridge MA: MIT Press. ELLIS, N. (2002). Frequency effects in language processing. A review with implications for theories of implicit and explicit language learning. Studies in Second Language Acquisition 24: 143-188. GRANFELDT, J. (2003). L’acquisition d
|
|
| 29. |
|
|
| 30. |
- Gruber, Thomas, et al.
(författare)
-
Geodetic SAR for Baltic Height System Unification and Baltic Sea Level Research
- 2021
-
Rapport (refereegranskat)abstract
- Traditionally, sea level is observed at tide gauge stations, which usually also serve as height reference stations for national levelling networks and therefore define a height system of a country. Thus, sea level research across countries is closely linked to height system unification and needs to be regarded jointly. The project aims to make use of a new observation technique, namely SAR positioning, which can help to connect the GNSS basic network of a country to tide gauge stations and as such to link the sea level records of tide gauge stations to the geometric network. By knowing the geoid heights at the tide gauge stations in a global height reference frame with high precision, one can finally obtain absolute sea level heights of the tide gauge stations in a common reference system and can link them together. By this method, on the one hand national height systems can be connected and on the other hand the absolute sea level at the tide gauge stations can be determined. By analysing time series of absolute sea level heights their changes can be determined in an absolute sense in a global reference frame and the impact of climate change on sea level can be quantified (e.g. by ice sheet and glacier melting, water inflow, global warming). The major scientific challenges to be addressed by this project then can be summarized as follows: (1) Connection of the tide gauge markers with the GNSS network geometrically in order to determine the relative vertical motion and to correct the tide gauge readings. For this the new technique of SAR positioning is applied. (2) Determination of a GOCE based high resolution geoid at tide gauge stations in order to deliver absolute heights of tide gauges with respect to a global equipotential surface as reference. (3) Joint analysis of geometrical and physical reference frames to make them compatible, and to determine corrections to be applied for combined analysis of geometric and physical heights.
|
|
| 31. |
- Gruber, Thomas, et al.
(författare)
-
Geodetic SAR for Height System Unification and Sea Level Research - Observation Concept and Preliminary Results in the Baltic Sea
- 2020
-
Ingår i: Remote Sensing. - : MDPI AG. - 2072-4292. ; 12:22
-
Tidskriftsartikel (refereegranskat)abstract
- Traditionally, sea level is observed at tide gauge stations, which usually also serve as height reference stations for national leveling networks and therefore define a height system of a country. One of the main deficiencies to use tide gauge data for geodetic sea level research and height systems unification is that only a few stations are connected to the geometric network of a country by operating permanent GNSS receivers next to the tide gauge. As a new observation technique, absolute positioning by SAR using active transponders on ground can fill this gap by systematically observing time series of geometric heights at tide gauge stations. By additionally knowing the tide gauge geoid heights in a global height reference frame, one can finally obtain absolute sea level heights at each tide gauge. With this information the impact of climate change on the sea level can be quantified in an absolute manner and height systems can be connected across the oceans. First results from applying this technique at selected tide gauges at the Baltic coasts are promising but also exhibit some problems related to the new technique. The paper presents the concept of using the new observation type in an integrated sea level observing system and provides some early results for SAR positioning in the Baltic sea area.
|
|
| 32. |
- Gruber, Thomas, et al.
(författare)
-
Geodetic SAR for Height System Unification and Sea Level Research - Observation Concept and Results in the Baltic Sea
- 2022
-
Konferensbidrag (refereegranskat)abstract
- Traditionally, sea level is observed at tide gauge stations, which usually also serve as height reference stations for national leveling networks and therefore define a height system of a country. Thus, sea level research across countries is closely linked to height system unification and needs to be regarded jointly. One of the main deficiencies to use tide gauge data for geodetic sea level research and height systems unification is that only a few stations are connected to permanent GNSS receivers next to the tide gauge in order to systematically observe vertical land motion. As a new observation technique, absolute positioning by SAR using active transponders on ground can fill this gap by systematically observing time series of geometric heights at tide gauge stations. By additionally knowing the tide gauge geoid heights in a global height reference frame, one can finally obtain absolute sea level heights at each tide gauge. With this information the impact of climate change on the sea level can be quantified in an absolute manner and height systems can be connected across the oceans.The paper presents the results of a project, which was conducted in the years 2019 to 2021 in the frame of ESA´s Baltic+ initiative. Within this project a test network of electronic corner reflectors (ECR) as targets for Sentinel-1 was realized in the Baltic Sea area. The ECR locations were either co-located with tide gauges or with permanent GNSS stations in order to observe systematically the ellipsoidal heights of the tide gauges and possibly also any vertical land motion at the stations. Data for the year 2020 were collected at 10 stations in Estonia, Finland, Poland and Sweden and jointly analyzed with GNSS data, tide gauge records and regional geoid height estimates. The obtained results are promising, but also exhibit some problems related to the ECR´s and their performance. At co-located GNSS stations the estimated ellipsoidal heights agree in a range between about 2 and 50 cm between both observation systems. From the results it could be identified that most likely variable systematic electronic instrument delays of the ECR´s are the main reason for these differences and that each instrument needs to be calibrated individually. Nevertheless, the project provides a valuable data set, which offers the possibility to enhance methods and procedures in order to develop the geodetic SAR positioning technique towards operability. All data and reports are accessible at the following web site: https://www.asg.ed.tum.de/iapg/baltic/
|
|
| 33. |
- Gruber, Thomas, et al.
(författare)
-
Geodetic SAR for Height System Unification and Sea Level Research - Results in the Baltic Sea Test Network
- 2022
-
Ingår i: Remote Sensing. - : MDPI. - 2072-4292. ; 14:14
-
Tidskriftsartikel (refereegranskat)abstract
- Coastal sea level is observed at tide gauge stations, which usually also serve as height reference stations for national networks. One of the main issues with using tide gauge data for sea level research is that only a few stations are connected to permanent GNSS stations needed to correct for vertical land motion. As a new observation technique, absolute positioning by SAR using off the shelf active radar transponders can be installed instead. SAR data for the year 2020 are collected at 12 stations in the Baltic Sea area, which are co-located to tide gauges or permanent GNSS stations. From the SAR data, 3D coordinates are estimated and jointly analyzed with GNSS data, tide gauge records and regional geoid height estimates. The obtained results are promising but also exhibit some problems related to the electronic transponders and their performance. At co-located GNSS stations, the estimated ellipsoidal heights agree in a range between about 2 and 50 cm for both observation systems. From the results, it can be identified that, most likely, variable systematic electronic instrument delays are the main reason, and that each transponder instrument needs to be calibrated individually. Nevertheless, the project provides a valuable data set, which offers the possibility of enhancing methods and procedures in order to develop a geodetic SAR positioning technique towards operability.
|
|
| 34. |
- Gärdenäs, Annemieke, et al.
(författare)
-
Knowledge gaps in soil carbon and nitrogen interactions - From molecular to global scale
- 2011
-
Ingår i: Soil Biology and Biochemistry. - : Elsevier BV. - 0038-0717 .- 1879-3428. ; 43, s. 702-717
-
Tidskriftsartikel (refereegranskat)abstract
- The objective of this review was to identify, address and rank knowledge gaps in our understanding of five major soil C and N interactions across a range of scales – from molecular to global. The studied five soil C and N interactions are: i) N controls on the soil emissions of greenhouse gases, ii) plant utilisation of organic N, iii) impact of rhizosphere priming on C and N cycling, iv) impact of black N on the stabilisation of soil organic matter (SOM) and v) representation of fractions of SOM in simulation models. We ranked the identified knowledge gaps according to the importance we attached to them for functional descriptions of soil–climate interactions at the global scale, for instance in general circulation models (GCMs). Both the direct and indirect influences on soil–climate interactions were included. We found that the level of understanding declined as the scale increased from molecular to global for four of the five topics. By contrast, the knowledge level for SOM simulation models appeared to be highest when considered at the ecosystem scale. The largest discrepancy between knowledge level and importance was found at the global modelling scale. We concluded that a reliable quantification of greenhouse gas emissions at the ecosystem scale is of utmost importance for improving soil–climate representation in GCMs. We see as key questions the identification of the role of different N species for the temperature sensitivity of SOM decomposition rates and its consequences for plant available N
|
|
| 35. |
|
|
| 36. |
|
|
| 37. |
- Hede, Thomas, 1975-, et al.
(författare)
-
A theoretical study revealing the promotion of light-absorbing carbon particles solubilization by natural surfactants in nanosized water droplets
- 2013
-
Ingår i: Atmospheric Science Letters. - : Wiley. - 1530-261X. ; 14:2, s. 86-90
-
Tidskriftsartikel (refereegranskat)abstract
- Many identified effects of atmospheric aerosol particles on climate come from pollutants. The effects of light-absorbing carbon particles (soot) are amongst the most uncertain and they are also considered to cause climate warming on the same order of magnitude as anthropogenic carbon dioxide. This study contributes to the understanding of the potential for transformation of the surface character of soot from hydrophobic to hydrophilic, which in clouds promotes a build-up of water-soluble material. We use molecular dynamics simulations to show how natural surfactants facilitate solubilization of fluoranthene, which we use as a model compound for soot in nanoaerosol water clusters.
|
|
| 38. |
- Hede, Thomas, et al.
(författare)
-
HULIS in Nanoaerosol Clusters; Investigations of Surface Tension and Aggregate Formation using Molecular Dynamics Simulations
- 2011
-
Ingår i: Atmospheric Chemistry and Physics Discussions. - : Copernicus GmbH. - 1680-7367 .- 1680-7375.
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Cloud condensation nuclei act as cores for water vapor condensation, and their composition and chemical properties may enhance or depress the ability for droplet growth. In this study we use molecular dynamics simulations to show that humic-like substances of larger systems (8.6 nm in diameter) mimic experimental data well referring to reduction of surface tension. The structural properties examined show the ability for the humic-like substances to aggregate inside the nanoaerosol clusters.
|
|
| 39. |
- Hede, Thomas, 1975-, et al.
(författare)
-
Model HULIS compounds in nanoaerosol clusters : investigations of surface tension and aggregate formation using molecular dynamics simulations
- 2011
-
Ingår i: Atmospheric Chemistry And Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 11:13, s. 6549-6557
-
Tidskriftsartikel (refereegranskat)abstract
- Cloud condensation nuclei act as cores for water vapour condensation, and their composition and chemical properties may enhance or depress the ability for droplet growth. In this study we use molecular dynamics simulations to show that model humic-like substances (HULIS) in systems containing 10 000 water molecules mimic experimental data well referring to reduction of surface tension. The model HULIS compounds investigated in this study are cis-pinonic acid (CPA), pinic acid (PAD) and pinonaldehyde (PAL). The structural properties examined show the ability for the model HULIS compounds to aggregate inside the nanoaerosol clusters.
|
|
| 40. |
- Hede, Thomas, et al.
(författare)
-
Simulations of Light Absorption of Carbon Particles in Nanoaerosol Clusters
- 2014
-
Ingår i: Journal of Physical Chemistry A. - : American Chemical Society (ACS). - 1089-5639 .- 1520-5215. ; 118:10, s. 1879-1886
-
Tidskriftsartikel (refereegranskat)abstract
- Black carbon soot (BS) is considered to be the second most contributing organic matter next to carbon dioxide for the global warming effect. There is, however, so far no consensus on the quantitative warming effect due to the increased distribution of black carbon in the atmosphere. A recent report (Science 2012, 337, 1078) suggests that due to BS there is only a few percentage enhancement in absorption of BS-immersed aerosols. To get proper interpretation of the available experimental data, it becomes essential to obtain details of the microscopic origin of the absorption and scattering processes of the aerosol clusters due to the presence of soot. However, so far, due to the large spatial scale and the need for a quantum mechanical description of the particles involved in the absorption and scattering, this quest has posed an insurmountable challenge. In the present work we propose the use of a multiscale integrated approach based on molecular dynamics and a quantum mechanical molecular mechanical method to model the optical property of molecules immersed in nanosized aerosol particles. We choose fluoranthene (FA) with varying cis-pinonic acid (CPA) impurity concentration as an illustrative example of application. We observe that normally FA tends to be on the surface of the nanoaerosols but in the presence of CPA impurities its spatial location changes to a core aggregate to some extent. We find that the absorption maximum is only slightly red-shifted in the presence of increased CPA concentrations and that the oscillator strengths are not altered significantly. The comparable values for the oscillator strengths of all the low energy excitations suggest that the absorption enhancement of the aerosol due to BS will not be substantial, which is in line with the recent experimental report in Science.
|
|
| 41. |
- Hoppe, Johanna M., 1981-
(författare)
-
Emotional mental imagery and the reduction of fear within the mind’s eye
- 2021
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Mental imagery refers to sensory-perceptual experiences in the absence of external sensory input. Emotional mental imagery (i.e., imagery with emotional content) is a key feature in many mental disorders, such as the image-based intrusive memories of trauma in posttraumatic stress disorder (PTSD). However, mental imagery can also be a vehicle for emotional change. In imaginal exposure, fear-provoking events are revisited using mental imagery. Imaginal exposure is a core component in evidence-based therapies for anxiety and PTSD. Treatment development is needed, as effects are many times insufficient, accessibility is low, and the treatment is not well-tolerated by some patients. The aim of this thesis was to increase knowledge of underlying mechanisms of imaginal exposure and improve our understanding of emotional mental imagery. The thesis explored the neural underpinnings of imaginal exposure and investigated mechanisms that could enhance its effectiveness, accessibility and tolerability. To further our knowledge of intrusive memories in PTSD (i.e., involuntary mental imagery), the characteristics of trauma memory hotspots (worst moments) collected within the first hours after trauma were explored. Study I demonstrated that imaginal exposure to mental imagery of phobic (vs. neutral) stimuli robustly activated emotion-processing brain areas. Study I also revealed that a brief 10-minute session of imaginal exposure was associated with reduced fear one week later. Study II investigated the link between vividness (clarity and liveliness) of mental imagery during imaginal exposure and reduction of fear using an experimental analogue of imaginal exposure (imaginal extinction). No evidence was found that high imagery vividness during imaginal extinction was associated with better long-term reduction in physiological fear responses than lower vividness. Study III revealed that hotspots collected soon after trauma are expressed as motion-rich sensory-perceptual experiences (mental imagery) with little detail on emotion/cognition. The contributions of this thesis involve demonstrating that mental imagery has the power to elicit emotional responses at subjective, physiological and neural levels and suggesting new avenues for treatment development. Future studies should explore the benefits of briefer imaginal exposure sessions to improve the effectiveness and accessibility of imaginal exposure. Future studies should also examine if fear reduction can be obtained with less vivid imaginal exposure, which could help attenuate distress and thereby make imaginal exposure tolerable for more patients. Lastly, the dynamic and visuospatial nature of newly formed trauma memory hotspots may help elucidate mechanisms through which tasks conducted posttrauma can prevent intrusive memories.
|
|
| 42. |
- Hoppe, Johanna M., et al.
(författare)
-
Exploring the neural basis of fear produced by mental imagery : imaginal exposure in individuals fearful of spiders
- 2021
-
Ingår i: Philosophical Transactions of the Royal Society of London. Biological Sciences. - : Royal Society. - 0962-8436 .- 1471-2970. ; 376:1817
-
Tidskriftsartikel (refereegranskat)abstract
- Imaginal exposure, i.e. reducing fear using exposure to mental imagery, is a widely used psychological treatment technique for dysfunctional fears. Yet, little is known about its underlying neural mechanisms. The present study examines the neural basis of imaginal exposure using a novel experimental procedure consisting of repeated exposure to flashpoint mental imagery of phobic (spiders) and neutral (gloves) stimuli. Whether the 10 min long imaginal exposure procedure could reduce fear responses was examined one week later. Thirty participants fearful of spiders underwent the experimental procedure. Neural activity was assessed using functional magnetic resonance imaging (session 1). Subjective fear and skin conductance responses were measured throughout the study (sessions 1 and 2). Imaginal exposure evoked intense fear and heightened skin conductance responses, and indicated robust activation in several brain regions, including amygdala, midcingulate cortex and insula. Findings demonstrate that neural activity in fear-processing brain areas can be elicited solely by generating a mental image of a phobic stimulus, that is, in the absence of the percept. Relevant for treatment development, results reveal that a single 10 min session of brief exposures to flashpoint mental imagery can lead to lasting reductions in phobic fear at both the subjective and physiological levels.This article is part of the theme issue 'Offline perception: voluntary and spontaneous perceptual experiences without matching external stimulation'.
|
|
| 43. |
- Hoppe, Johanna M., et al.
(författare)
-
Hotspots in the immediate aftermath of trauma : Mental imagery of worst moments highlighting time, space and motion
- 2022
-
Ingår i: Consciousness and Cognition. - : Elsevier. - 1053-8100 .- 1090-2376. ; 99
-
Tidskriftsartikel (refereegranskat)abstract
- Intrusive memories of trauma (memories that enter consciousness involuntarily) highjack cognitive processing, cause emotional distress, and represent a core symptom of posttraumatic stress disorder. Intrusive memories often contain the worst moment/s (‘hotspots’) of the trauma memory. Little is known about hotspots shortly after they are formed, i.e., in the first hours after trauma. We investigated the features of hotspots in trauma-exposed individuals (n = 21) within 72 h post-trauma, using linguistic analysis and qualitative coding. On average, participants reported three hotspots per traumatic event (M = 7.8 words/hotspot). Hotspots primarily contained words related to time, space, motion, and sensory processing. Most hotspots contained sensory features (97%) and motion (59%). Few cognitions and no emotion words were identified. Results indicate that hotspots collected shortly post-trauma are expressed as motion-rich sensory-perceptual experiences (mental imagery) with little detail about emotion/cognition. Findings are discussed in terms of the function of hotspots (e.g., preparedness for action) and clinical implications.
|
|
| 44. |
- Hoppe, Johanna M., et al.
(författare)
-
Imaginal extinction and the vividness of mental imagery : Exploring the reduction of fear within the mind’s eye
- 2022
-
Ingår i: Behavioural Brain Research. - : Elsevier. - 0166-4328 .- 1872-7549. ; 418
-
Tidskriftsartikel (refereegranskat)abstract
- Patients are encouraged to produce vivid mental imagery during imaginal exposure, as it is assumed to promote fear reduction. Nevertheless, the link between fear reduction and imagery vividness is unclear. We investigated the impact of vividness on fear responses using an experimental analogue of imaginal exposure - imaginal extinction - in which conditioned fear, measured with skin conductance, is reduced through exposure to mental imagery of the conditioned stimulus. We examined (1) if task-specific vividness (high vs low) of the conditioned stimulus during imaginal extinction moderated the reduction of fear responses, and (2) if task-specific vividness influenced remaining fear responses 24 h later. Findings suggest that high vividness may be advantageous for fear reduction during imaginal extinction, but it may not influence fear responses in the longer term. A possible clinical implication is that high imagery vividness during imaginal exposure may not be vital for overall treatment outcome. As high vividness is associated with increased levels of distress, a future direction would be to explore whether similar fear reduction can be obtained with less vivid imaginal exposure and thereby make treatment tolerable for more patients.
|
|
| 45. |
- Izsak, Julia, et al.
(författare)
-
TGF-β1 Suppresses Proliferation and Induces Differentiation in Human iPSC Neural in vitro Models
- 2020
-
Ingår i: Frontiers in Cell and Developmental Biology. - : Frontiers Media SA. - 2296-634X. ; 8
-
Tidskriftsartikel (refereegranskat)abstract
- Persistent neural stem cell (NSC) proliferation is, among others, a hallmark of immaturity in human induced pluripotent stem cell (hiPSC)-based neural models. TGF-β1 is known to regulate NSCs in vivo during embryonic development in rodents. Here we examined the role of TGF-β1 as a potential candidate to promote in vitro differentiation of hiPSCs-derived NSCs and maturation of neuronal progenies. We present that TGF-β1 is specifically present in early phases of human fetal brain development. We applied confocal imaging and electrophysiological assessment in hiPSC-NSC and 3D neural in vitro models and demonstrate that TGF-β1 is a signaling protein, which specifically suppresses proliferation, enhances neuronal and glial differentiation, without effecting neuronal maturation. Moreover, we demonstrate that TGF-β1 is equally efficient in enhancing neuronal differentiation of human NSCs as an artificial synthetic small molecule. The presented approach provides a proof-of-concept to replace artificial small molecules with more physiological signaling factors, which paves the way to improve the physiological relevance of human neural developmental in vitro models.
|
|
| 46. |
- Laenen, Benjamin, et al.
(författare)
-
Demography and mating system shape the genome-wide impact of purifying selection in Arabis alpina
- 2018
-
Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 115:4, s. 816-821
-
Tidskriftsartikel (refereegranskat)abstract
- Plant mating systems have profound effects on levels and structuring of genetic variation and can affect the impact of natural selection. Although theory predicts that intermediate outcrossing rates may allow plants to prevent accumulation of deleterious alleles, few studies have empirically tested this prediction using genomic data. Here, we study the effect of mating system on purifying selection by conducting population-genomic analyses on whole-genome resequencing data from 38 European individuals of the arctic-alpine crucifer Arabis alpina. We find that outcrossing and mixed-mating populations maintain genetic diversity at similar levels, whereas highly self-fertilizing Scandinavian A. alpina show a strong reduction in genetic diversity, most likely as a result of a postglacial colonization bottleneck. We further find evidence for accumulation of genetic load in highly self-fertilizing populations, whereas the genome-wide impact of purifying selection does not differ greatly between mixed-mating and outcrossing populations. Our results demonstrate that intermediate levels of outcrossing may allow efficient selection against harmful alleles, whereas demographic effects can be important for relaxed purifying selection in highly selfing populations. Thus, mating system and demography shape the impact of purifying selection on genomic variation in A. alpina. These results are important for an improved understanding of the evolutionary consequences of mating system variation and the maintenance of mixed-mating strategies.
|
|
| 47. |
|
|
| 48. |
- Laudon, Hjalmar, et al.
(författare)
-
Patterns and Dynamics of Dissolved Organic Carbon (DOC) in Boreal Streams : The Role of Processes, Connectivity, and Scaling
- 2011
-
Ingår i: Ecosystems (New York. Print). - New York, NY : Springer. - 1432-9840 .- 1435-0629. ; 14:6, s. 880-893
-
Tidskriftsartikel (refereegranskat)abstract
- We bring together three decades of research from a boreal catchment to facilitate an improved mechanistic understanding of surface water dissolved organic carbon (DOC) regulation across multiple scales. The Krycklan Catchment Study encompasses 15 monitored nested research catchments, ranging from 3 to 6900 ha in size, as well as a set of monitored transects of forested and wetland soils. We show that in small homogenous catchments, hydrological functioning provides a first order control on the temporal variability of stream water DOC. In larger, more heterogeneous catchments, stream water DOC dynamics are regulated by the combined effect of hydrological mechanisms and the proportion of major landscape elements, such as wetland and forested areas. As a consequence, streams with heterogeneous catchments undergo a temporal switch in the DOC source. In a typical boreal catchment covered by 10-20% wetlands, DOC originates predominantly from wetland sources during low flow conditions. During high flow, the major source of DOC is from forested areas of the catchment. We demonstrate that by connecting knowledge about DOC sources in the landscape with detailed hydrological process understanding, an improved representation of stream water DOC regulation can be provided. The purpose of this study is to serve as a framework for appreciating the role of regulating mechanisms, connectivity and scaling for understanding the pattern and dynamics of surface water DOC across complex landscapes. The results from this study suggest that the sensitivity of stream water DOC in the boreal landscape ultimately depends on changes within individual landscape elements, the proportion and connectivity of these affected landscape elements, and how these changes are propagated downstream.
|
|
| 49. |
- Laurien, Thomas, 1967, et al.
(författare)
-
Ingen Å Är en Ö : Ingen Å Är en Ö - utställningen
- 2022
-
Ingår i: Rydals museum, Rydal, 21 maj - 9 okt.
-
Konstnärligt arbete (övrigt vetenskapligt/konstnärligt)abstract
- Utställningen "Ingen Å Är en Ö" visades på Rydals museum, 21 maj - 9 okt 2022. Den är del av det treåriga projektet "Skimmer och härvor i Viskans vatten och marker". I den kuraterade utställningen visades beställda konstverk och texter av en rad olika konstnärer, forskare, poeter m.fl., samt processmaterial från grupper av människor som genom projektet på olika sätt blivit engagerade i utställningens tema: människans relationer med fler-än-människor, med särskilt fokus på vattenkroppen Viskan (Viskans avrinningsområde). I utställningen väcks frågor om människans roll och relationer till vatten, djur, växter, m.m., både i dåtid, nutid och framtid. Medverkande: Caroline Mårtensson, Eva Hild, Isak Eldh, Jesper Norda, Karolina EYWA Carlsson, Kennet Öhlund, Lina Ekdahl, Marks Konstgrafiska Verkstad/skaparverkstaden, Dômen Konstskola/konstkollo, MASU (Mattias Gunnarsson & Susanne Westerberg), Mathilda Dahlquist, Theo Ågren, Thomas Laurien, Flow Feelers-gruppen, Tove Möller, Ulrika Jansson, Funkisgruppen i Kreativa spår på Kulturskolan i Mark, Rydals museums ”skapande skola”-aktivitet, Fanny Lindh, Pamela Jaskoviak, Janne Kantola, Christine Hansen, Daniel Svensson samt Linnéa Jägrud. Curatorer: Thomas Laurien och Theo Ågren. Grafisk form: Eva Erwander. Finansiering: Boråsregionen, Rydals museum samt HDK-Valand vid Göteborgs universitet.
|
|
| 50. |
- Laurien, Thomas, 1967, et al.
(författare)
-
"Skimmer och härvor i Viskadalen - insamlande av berättelser genom workshoppar 2019." : “Shimmer and Entanglements in the River Basin of Viskan - collection of stories through workshops 2019”
- 2019
-
Ingår i: Workshop 2019:1 - Programpunkt under “Earth Hour”, inbjudna av arrangören Marks Konstgrafiska Verkstad. Workshop 2019:2 - Programpunkt under “Väverskans dag” i Kinna. Workshop 2019:3 - “Viskan Extended”. Deltagande i programpunkt under GIBCA Extended, inbjudna av Art Center Sjuhärad. Workshop 2019:4 - “Relational Waters”. Deltagande i programpunkt under GIBCA Extended, inbjudna av Stationen i Svenshögen. Workshop 2019:5 - Under ett offentligt berättarcafé inbjudna av De Sju häradernas kulturhistoriska förening..
-
Konstnärligt arbete (övrigt vetenskapligt/konstnärligt)abstract
- ”Skimmer och härvor i Viskadalen” är ett processbaserat tvärdisciplinärt projekt. Det övergripande syftet är att med framför allt konstnärliga medel och förhållningssätt undersöka människors situerade relationer till det mer-än-mänskliga.
|
|
