| 1. |
- Moberg, Christina, et al.
(författare)
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De unga gör helt rätt när de stämmer staten
- 2022
-
Ingår i: Aftonbladet. - 1103-9000.
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- 1 620 forskare och lärare i forskarvärlden: Vi ställer oss bakom Auroras klimatkrav
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| 2. |
- Mortensen, Jens Jorgen, et al.
(författare)
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GPAW: An open Python package for electronic structure calculations
- 2024
-
Ingår i: Journal of Chemical Physics. - 1089-7690 .- 0021-9606. ; 160:9
-
Tidskriftsartikel (refereegranskat)abstract
- We review the GPAW open-source Python package for electronic structure calculations. GPAW is based on the projector-augmented wave method and can solve the self-consistent density functional theory (DFT) equations using three different wave-function representations, namely real-space grids, plane waves, and numerical atomic orbitals. The three representations are complementary and mutually independent and can be connected by transformations via the real-space grid. This multi-basis feature renders GPAW highly versatile and unique among similar codes. By virtue of its modular structure, the GPAW code constitutes an ideal platform for the implementation of new features and methodologies. Moreover, it is well integrated with the Atomic Simulation Environment (ASE), providing a flexible and dynamic user interface. In addition to ground-state DFT calculations, GPAW supports many-body GW band structures, optical excitations from the Bethe-Salpeter Equation, variational calculations of excited states in molecules and solids via direct optimization, and real-time propagation of the Kohn-Sham equations within time-dependent DFT. A range of more advanced methods to describe magnetic excitations and non-collinear magnetism in solids are also now available. In addition, GPAW can calculate non-linear optical tensors of solids, charged crystal point defects, and much more. Recently, support for graphics processing unit (GPU) acceleration has been achieved with minor modifications to the GPAW code thanks to the CuPy library. We end the review with an outlook, describing some future plans for GPAW.
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| 3. |
- Thapper, Johan, 1977-
(författare)
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Combinatorial Considerations on Two Models from Statistical Mechanics
- 2007
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Interactions between combinatorics and statistical mechanics have provided many fruitful insights in both fields. A compelling example is Kuperberg’s solution to the alternating sign matrix conjecture, and its following generalisations. In this thesis we investigate two models from statistical mechanics which have received attention in recent years.The first is the fully packed loop model. A conjecture from 2001 by Razumov and Stroganov opened the field for a large ongoing investigation of the O(1) loop model and its connections to a refinement of the fully packed loop model. We apply a combinatorial bijection originally found by de Gier to an older conjecture made by Propp.The second model is the hard particle model. Recent discoveries by Fendley et al. and results by Jonsson suggests that the hard square model with cylindrical boundary conditions possess some beautiful combinatorial properties. We apply both topological and purely combinatorial methods to related independence complexes to try and gain a better understanding of this model.
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| 4. |
- Barth, Julia M.I., et al.
(författare)
-
Genome architecture enables local adaptation of Atlantic cod despite high connectivity
- 2017
-
Ingår i: Molecular Ecology. - : Wiley. - 0962-1083 .- 1365-294X. ; 26:17, s. 4452-4466
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Tidskriftsartikel (refereegranskat)abstract
- Adaptation to local conditions is a fundamental process in evolution; however, mechanisms maintaining local adaptation despite high gene flow are still poorly understood. Marine ecosystems provide a wide array of diverse habitats that frequently promote ecological adaptation even in species characterized by strong levels of gene flow. As one example, populations of the marine fish Atlantic cod (Gadus morhua) are highly connected due to immense dispersal capabilities but nevertheless show local adaptation in several key traits. By combining population genomic analyses based on 12K single nucleotide polymorphisms with larval dispersal patterns inferred using a biophysical ocean model, we show that Atlantic cod individuals residing in sheltered estuarine habitats of Scandinavian fjords mainly belong to offshore oceanic populations with considerable connectivity between these diverse ecosystems. Nevertheless, we also find evidence for discrete fjord populations that are genetically differentiated from offshore populations, indicative of local adaptation, the degree of which appears to be influenced by connectivity. Analyses of the genomic architecture reveal a significant overrepresentation of a large ~5 Mb chromosomal rearrangement in fjord cod, previously proposed to comprise genes critical for the survival at low salinities. This suggests that despite considerable connectivity with offshore populations, local adaptation to fjord environments may be enabled by suppression of recombination in the rearranged region. Our study provides new insights into the potential of local adaptation in high gene flow species within fine geographical scales and highlights the importance of genome architecture in analyses of ecological adaptation.
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| 5. |
- Binde, Per, 1956, et al.
(författare)
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Inledning: Spelberoendes riksförbund tio år
- 2010
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Ingår i: Spelberoendes riksförbund 10 år: En jubileumsskrift, red. P. Binde & J. Jonsson. - Östersund : Statens folkhälsoinstitut. - 9789172576858 ; , s. 6-11
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Den svenska spelmarknaden har förändrats och växt kraftigt den senaste tioårsperioden. Vi har fått statliga kasinon och på Internet går det att spela på det mesta från bingo till poker. Så gott som dagligen rapporterar massmedia om spelpolitik och spelberoende. Medvetenheten om spelberoende har ökat och starkt bidragande till det är Spelberoendes riksförbund. Förbundet har i tio år informerat om spelberoende och gett stöd till människor med spelproblem och deras anhöriga. Den här jubileumsskriften ger en bild av spelproblem i Sverige och kamratstödet i spelberoendes föreningar. Ungas spelande och de anhörigas situation tas upp av flera författare. Läsaren får också veta hur medvetenheten om spelberoende växte fram i Sverige och ta del av diskussioner om hur framtidens spelande kan gestalta sig. I boken medverkar aktiva inom förbundet, eldsjälar från lokalföreningar och spelberoende som har fått hjälp. Även spelforskare och personer som på olika sätt arbetat med spelfrågor har bidragit med kapitel. Skriften är utgiven med stöd av Statens folkhälsoinstitut. I detta inledningskapitel presenteras spelberoendes riksförbund, författarna och deras bidrag till jubileumsskriften.
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| 6. |
- Caplat, Paul, et al.
(författare)
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Looking beyond the mountain: dispersal barriers in a changing world
- 2016
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Ingår i: Frontiers in Ecology and the Environment. - : Wiley. - 1540-9295 .- 1540-9309. ; 14:5, s. 262-269
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Tidskriftsartikel (refereegranskat)abstract
- Dispersal barriers have demographic, evolutionary, and ecosystem-wide consequences. With ongoing changes in the environment, some dispersal barriers will likely disappear while new ones will appear, and it is crucial to understand these dynamics to forecast species' distributions and adaptive potential. Here we review recent literature on the ecological and evolutionary aspects of dispersal to highlight key dynamics of dispersal barriers in the face of global change. After defining dispersal barriers, we explain that a better understanding of their dynamics requires identifying the barrier types that are most susceptible to change and predicting species' responses. This knowledge is a prerequisite for designing management strategies to increase or reduce connectivity, and maintain adaptive potential. Our intent is to motivate researchers to explicitly consider dispersal barriers in order to better forecast the dynamics of species and ecosystems subject to global change.
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| 7. |
- Carlbring, Per, 1972-, et al.
(författare)
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Internet-based treatment of pathological gambling with a three-year follow-up
- 2012
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Ingår i: Cognitive Behaviour Therapy. - : Routledge. - 1650-6073 .- 1651-2316. ; 41:4, s. 321-34
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Tidskriftsartikel (refereegranskat)abstract
- Effective therapies for pathological gambling exist, but their use is limited to about 10% of the target population. In an attempt to lower the barriers for help, Internet-based cognitive behavioural therapy (ICBT) has been shown to be effective when delivered to a non-depressed sample with pathological gambling. This study sought to extend this finding to a larger, more representative population, and also test a model to predict responder status. Following advertisement, a total of 284 participants started an 8-week ICBT programme with minimal therapist contact via e-mail and weekly telephone calls of less than 15 min. The average time spent on each participant, including telephone conversations, e-mail, and administration, was 4 h. In addition to a mixed effects model to evaluate the effectiveness of the treatment, two logistic regression analyses were performed with the following eight pre-defined response predictor variables: work-life satisfaction, primary gambling activity, debts due to gambling, social support, personal yearly salary, alcohol consumption, stage of change, and dissociative gambling. ICBT resulted in statistically significant reductions in the scores of pathological gambling, anxiety, and depression as well as an increase in quality of life compared to pre-treatment levels. Follow-ups carried out in the treatment group at 6, 18, and 36 months indicated that treatment effects were sustained. Using the eight predictor variable model rendered an acceptable predictive ability to identify responders both at post-test (AUC = .72, p < .01) and at 36-month follow-up (AUC = .70, p < .01). We conclude that ICBT for pathological gamblers, even if depressed, can be effective and that outcome can partly be predicted by pre-treatment characteristics.
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| 8. |
- Carlbring, Per, et al.
(författare)
-
Spelberoende
- 2013. - 2
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Ingår i: KBT inom psykiatrin. - Stockholm : Natur och kultur. - 9789127135604 ; , s. 337-353
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Här beskrivs hur KBT kan tillämpas vid de vanligaste psykiatriska tillstånden. I denna uppdaterade och utvidgade utgåva har nya kapitel tillkommit, bland annat om fallformulering, spelberoende, internetbehandling samt KBT och psykofarmaka. (Från baksidestexten.)
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| 9. |
- Cederwall, Martin, et al.
(författare)
-
Canonical supermultiplets and their Koszul duals
- 2024
-
Ingår i: Communications in Mathematical Physics. - : Springer. - 0010-3616 .- 1432-0916. ; 405:5
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Tidskriftsartikel (refereegranskat)abstract
- The pure spinor superfield formalism reveals that, in any dimension and with any amount of supersymmetry, one particular supermultiplet is distinguished from all others. This “canonical supermultiplet” is equipped with an additional structure that is not apparent in any component-field formalism: a (homotopy) commutative algebra structure on the space of fields. The structure is physically relevant in several ways; it is responsible for the interactions in ten-dimensional super Yang–Mills theory, as well as crucial to any first-quantised interpretation. We study the L∞ algebra structure that is Koszul dual to this commutative algebra, both in general and in numerous examples, and prove that it is equivalent to the subalgebra of the Koszul dual to functions on the space of generalised pure spinors in internal degree greater than or equal to three. In many examples, the latter is the positive part of a Borcherds–Kac–Moody superalgebra. Using this result, we can interpret the canonical multiplet as the homotopy fiber of the map from generalised pure spinor space to its derived replacement. This generalises and extends work of Movshev–Schwarz and Gálvez–Gorbounov–Shaikh–Tonks in the same spirit. We also comment on some issues with physical interpretations of the canonical multiplet, which are illustrated by an example related to the complex Cayley plane, and on possible extensions of our construction, which appear relevant in an example with symmetry type G2 × A1 .
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| 10. |
- Conley, Daniel, et al.
(författare)
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Hypoxia is increasing in the coastal zone of the Baltic Sea
- 2011
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 45:16, s. 6777-6783
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Tidskriftsartikel (refereegranskat)abstract
- Hypoxia is a well-described phenomenon in the offshore waters of the Baltic Sea with both the spatial extent and intensity of hypoxia known to have increased due to anthropogenic eutrophication, however, an unknown amount of hypoxia is present in the coastal zone. Here we report on the widespread unprecedented occurrence of hypoxia across the coastal zone of the Baltic Sea. We have identified 115 sites that have experienced hypoxia during the period 1955-2009 increasing the global total to ca. 500 sites, with the Baltic Sea coastal zone containing over 20% of all known sites worldwide. Most sites experienced episodic hypoxia, which is a precursor to development of seasonal hypoxia. The Baltic Sea coastal zone displays an alarming trend with hypoxia steadily increasing with time since the 1950s effecting nutrient biogeochemical processes, ecosystem services, and coastal habitat.
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| 11. |
- Dierschke, Katrin, et al.
(författare)
-
Acute respiratory effects and biomarkers of inflammation due to welding-derived nanoparticle aggregates
- 2017
-
Ingår i: International Archives of Occupational and Environmental Health. - : Springer Science and Business Media LLC. - 0340-0131 .- 1432-1246. ; 90:5, s. 451-463
-
Tidskriftsartikel (refereegranskat)abstract
- Welders are exposed to airborne particles from the welding environment and often develop symptoms work-related from the airways. A large fraction of the particles from welding are in the nano-size range. In this study we investigate if the welders' airways are affected by exposure to particles derived from gas metal arc welding in mild steel in levels corresponding to a normal welding day. In an exposure chamber, 11 welders with and 10 welders without work-related symptoms from the lower airways and 11 non-welders without symptoms, were exposed to welding fumes (1 mg/m(3)) and to filtered air, respectively, in a double-blind manner. Symptoms from eyes and upper and lower airways and lung function were registered. Blood and nasal lavage (NL) were sampled before, immediately after and the morning after exposure for analysis of markers of oxidative stress. Exhaled breath condensate (EBC) for analysis of leukotriene B4 (LT-B4) was sampled before, during and immediately after exposure. No adverse effects of welding exposure were found regarding symptoms and lung function. However, EBC LT-B4 decreased significantly in all participants after welding exposure compared to filtered air. NL IL-6 increased immediately after exposure in the two non-symptomatic groups and blood neutrophils tended to increase in the symptomatic welder group. The morning after, neutrophils and serum IL-8 had decreased in all three groups after welding exposure. Remarkably, the symptomatic welder group had a tenfold higher level of EBC LT-B4 compared to the two groups without symptoms. Despite no clinical adverse effects at welding, changes in inflammatory markers may indicate subclinical effects even at exposure below the present Swedish threshold limit (8 h TWA respirable dust).
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| 12. |
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| 13. |
- Ekqvist, David, et al.
(författare)
-
Safety and pharmacokinetics-pharmacodynamics of a shorter tuberculosis treatment with high-dose pyrazinamide and rifampicin : a study protocol of a phase II clinical trial (HighShort-RP)
- 2022
-
Ingår i: BMJ Open. - : BMJ Publishing Group Ltd. - 2044-6055. ; 12:3
-
Tidskriftsartikel (refereegranskat)abstract
- Introduction: Increased dosing of rifampicin and pyrazinamide seems a viable strategy to shorten treatment and prevent relapse of drug-susceptible tuberculosis (TB), but safety and efficacy remains to be confirmed. This clinical trial aims to explore safety and pharmacokinetics-pharmacodynamics of a high-dose pyrazinamide-rifampicin regimen.Methods and analysis: Adult patients with pulmonary TB admitted to six hospitals in Sweden and subjected to receive first-line treatment are included. Patients are randomised (1:3) to either 6-month standardised TB treatment or a 4-month regimen based on high-dose pyrazinamide (40 mg/kg) and rifampicin (35 mg/kg) along with standard doses of isoniazid and ethambutol. Plasma samples for measurement of drug exposure determined by liquid chromatography tandem-mass spectrometry are obtained at 0, 1, 2, 4, 6, 8, 12 and 24 hours, at day 1 and 14. Maximal drug concentration (C-max) and area under the concentration-time curve (AUC(0-24h)) are estimated by non-compartmental analysis. Conditions for early model-informed precision dosing of high-dose pyrazinamide-rifampicin are pharmacometrically explored. Adverse drug effects are monitored throughout the study and graded according to Common Terminology Criteria for Adverse Events V.5.0. Early bactericidal activity is assessed by time to positivity in BACTEC MGIT 960 of induced sputum collected at day 0, 5, 8, 15 and week 8. Minimum inhibitory concentrations of first-line drugs are determined using broth microdilution. Disease severity is assessed with X-ray grading and a validated clinical scoring tool (TBscore II). Clinical outcome is registered according to WHO definitions (2020) in addition to occurrence of relapse after end of treatment. Primary endpoint is pyrazinamide AUC(0-24h) and main secondary endpoint is safety.Ethics and dissemination: The study is approved by the Swedish Ethical Review Authority and the Swedish Medical Products Agency. Informed written consent is collected before study enrolment. The study results will be submitted to a peer-reviewed journal.
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| 14. |
- Elebro, Jacob, et al.
(författare)
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Prognostic and treatment predictive significance of SATB1 and SATB2 expression in pancreatic and periampullary adenocarcinoma
- 2014
-
Ingår i: Journal of Translational Medicine. - : Springer Science and Business Media LLC. - 1479-5876. ; 12, s. 289-
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Pancreatic cancer and other pancreaticobiliary type periampullary adenocarcinomas have a dismal prognosis even after resection and neoadjuvant chemotherapy. Intestinal type periampullary adenocarcinomas generally have a better prognosis, but little is known on optimal neoadjuvant and adjuvant treatment. New prognostic and treatment predictive biomarkers are needed for improved treatment stratification of patients with both types of periampullary adenocarcinoma. Expression of the Special AT-rich sequence-binding protein 1 (SATB1) has been demonstrated to confer a worse prognosis in several tumour types, whereas its close homologue SATB2 is a proposed diagnostic and favourable prognostic marker for colorectal cancer. The prognostic value of SATB1 and SATB2 expression in periampullary adenocarcinoma has not yet been described. Methods: Immunohistochemical expression of SATB1 and SATB2 was analysed in tissue microarrays with primary tumours and a subset of paired lymph node metastases from 175 patients operated with pancreaticoduodenectomy for periampullary adenocarcinoma. Kaplan-Meier and Cox regression analysis were applied to explore the impact of SATB1 and SATB2 expression on recurrence free survival (RFS) and overall survival (OS). Results: Positive expression of SATB1 was denoted in 16/106 primary pancreatobiliary type tumours and 11/65 metastases, and in 15/63 primary intestinal type tumours and 4/26 metastases, respectively. Expression of SATB1 was an independent predictor of a significantly shorter RFS and OS in pancreatobiliary type, but not in intestinal type adenocarcinomas. Moreover, SATB1 expression predicted an improved response to adjuvant chemotherapy in both tumour types. SATB2-expression was seen in 3/107 pancreatobiliary type primary tumours, and in 8/61 intestinal type primary tumours. The small number of cases with positive SATB2 expression did not allow for any firm conclusions on its prognostic value. Conclusions: These findings demonstrate the potential utility of SATB1 as a prognostic and predictive biomarker for chemotherapy response in both intestinal type and pancreatobiliary type periampullary adenocarcinomas, including pancreatic cancer.
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| 15. |
- Emtander, Eric, 1979-
(författare)
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On hypergraph algebras
- 2008
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)
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| 16. |
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| 17. |
- Engman, Jakob, et al.
(författare)
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Neisseria meningitidis Polynucleotide Phosphorylase Affects Aggregation, Adhesion, and Virulence
- 2016
-
Ingår i: Infection and Immunity. - 0019-9567 .- 1098-5522. ; 84:5, s. 1501-1513
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Tidskriftsartikel (refereegranskat)abstract
- Neisseria meningitidis autoaggregation is an important step during attachment to human cells. Aggregation is mediated by type IV pili and can be modulated by accessory pilus proteins, such as PilX, and posttranslational modifications of the major pilus subunit PilE. The mechanisms underlying the regulation of aggregation remain poorly characterized. Polynucleotide phosphorylase ( PNPase) is a 3'-5' exonuclease that is involved in RNA turnover and the regulation of small RNAs. In this study, we biochemically confirm that NMC0710 is the N. meningitidis PNPase, and we characterize its role in N. meningitidis pathogenesis. We show that deletion of the gene encoding PNPase leads to hyperaggregation and increased adhesion to epithelial cells. The aggregation induced was found to be dependent on pili and to be mediated by excessive pilus bundling. PNPase expression was induced following bacterial attachment to human cells. Deletion of PNPase led to global transcriptional changes and the differential regulation of 469 genes. We also demonstrate that PNPase is required for full virulence in an in vivo model of N. meningitidis infection. The present study shows that PNPase negatively affects aggregation, adhesion, and virulence in N. meningitidis.
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| 18. |
- Eriksson, Jens, et al.
(författare)
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Characterization of motility and piliation in pathogenic Neisseria
- 2015
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Ingår i: BMC Microbiology. - : Springer Science and Business Media LLC. - 1471-2180. ; 15
-
Tidskriftsartikel (refereegranskat)abstract
- Background: The type IV pili (Tfp) of pathogenic Neisseria (i. e., N. gonorrhoeae and N. meningitidis) are essential for twitching motility. Tfp retraction, which is dependent on the ATPase PilT, generates the forces that move bacteria over surfaces. Neisseria motility has mainly been studied in N. gonorrhoeae whereas the motility of N. meningitidis has not yet been characterized. Results: In this work, we analyzed bacterial motility and monitored Tfp retraction using live- cell imaging of freely moving bacteria. We observed that N. meningitidis moved over surfaces at an approximate speed of 1.6 mu m/s, whereas N. gonorrhoeae moved with a lower speed (1.0 mu/s). An alignment of the meningococcal and gonococcal pilT promoters revealed a conserved single base pair variation in the -10 promoter element that influence PilT expression. By tracking mutants with altered pilT expression or pilE sequence, we concluded that the difference in motility speed was independent of both. Live-cell imaging using total internal reflection fluorescence microscopy demonstrated that N. gonorrhoeae more often moved with fewer visible retracting filaments when compared to N. meningitidis. Correspondingly, meningococci also displayed a higher level of piliation in transmission electron microscopy. Nevertheless, motile gonococci that had the same number of filaments as N. meningitidis still moved with a lower speed. Conclusions: These data reveal differences in both speed and piliation between the pathogenic Neisseria species during twitching motility, suggesting a difference in Tfp-dynamics.
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| 19. |
- Fernaeus, Ylva, et al.
(författare)
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Beyond representations : Towards an action-centric perspective on tangible interaction
- 2008
-
Ingår i: International Journal of Arts and Technology. - : Inderscience Publishers. - 1754-8853 .- 1754-8861. ; 1:3/4, s. 249-267
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Tidskriftsartikel (refereegranskat)abstract
- In the light of theoretical as well as concrete technical development, we discuss a conceptual shift from an information-centric to an action-centric perspective on tangible interactive technology. We explicitly emphasise the qualities of shareable use, and the importance of designing tangibles that allow for meaningful manipulation and control of the digital material. This involves a broadened focus from studying properties of the interface, to instead aim for qualities of the activity of using a system, a general tendency towards designing for social and sharable use settings and an increased openness towards multiple and subjective interpretations. An effect of this is that tangibles are not designed as representations of data, but as resources for action. We discuss four ways that tangible artefacts work as resources for action: (1) for physical manipulation; (2) for referential, social and contextually oriented action; (3) for perception and sensory experience; (4) for digitally mediated action.
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| 20. |
- Fernaeus, Ylva, et al.
(författare)
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Revisiting the jacquard loom : threads of history and current patterns in HCI
- 2012
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Ingår i: CHI '12 Proceedings of the SIGCHI Conference on Human Factors in Computing Systems. - New York : Association for Computing Machinery (ACM). - 9781450310154 ; , s. 1593-1602
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Konferensbidrag (refereegranskat)abstract
- In the recent developments of human computer interaction, one central challenge has been to find and to explore alternatives to the legacy of the desktop computer paradigm for interaction design. To investigate this issue further we have conducted an analysis on a fascinating piece of machinery often referred to as one of the predecessors of the modern day computer, the Jacquard loom. In analysing the Jacquard loom we look at qualities in design and interaction from some different perspectives: how historical tools, crafts, and practices can inform interaction design, the role of physicality, materiality, and full-body interaction in order to rethink some current conceptions of interaction and design of computational devices.
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| 21. |
- Fernaeus, Ylva, et al.
(författare)
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Towards a new set of ideals : Consequences of the practice turn in tangible interaction
- 2008
-
Ingår i: TEI'08 - Second International Conference on Tangible and Embedded Interaction - Conference Proceedings. - New York, NY, USA : ACM Press. - 9781605580043 ; , s. 223-230
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Konferensbidrag (refereegranskat)abstract
- The practice-oriented turn in social sciences has implied a series of fundamental consequences and design challenges for HCI in general, and particularly in tangible interaction research. This could be interpreted as a move away from scientific ideals based on a modernist tradition, reflected in four contemporary themes in tangible interaction research. The first theme concerns a shift from an information centric to an action centric perspective on interaction. The second concerns a broadened focus from studying properties of the system, to instead aim at supporting qualities of the activity of using a system. The third concerns the general shift towards supporting sharable use, rather than primarily individual use settings. The last theme concerns the shift towards multiple and subjective interpretation of how to use new technological artefacts. We discuss how these themes are grounded in theoretical as well as more concrete technical developments in the area of tangible computing.
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| 22. |
-
Forward! – Bперёд! – Framåt! : Essays in Honour of Prof Dr Kaj Hobér
- 2019
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Samlingsverk (redaktörskap) (refereegranskat)abstract
- In August 2019 our dear friend and colleague Professor Dr Kaj Hobér retired from his position as a Professor of International Investment and Trade Law at the Faculty of Law at Uppsala University. In order to honor Kaj Hobér’s long time commitment to academia and his successful career as a lawyer and partner of Mannheimer Swartling, a group of friends and colleagues have come together to present a collection of essays in his honor.
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| 23. |
- Fristedt, Richard, et al.
(författare)
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Reduced expression of the polymeric immunoglobulin receptor in pancreatic and periampullary adenocarcinoma signifies tumour progression and poor prognosis
- 2014
-
Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 9:11, s. 112728-112728
-
Tidskriftsartikel (refereegranskat)abstract
- The polymeric immunoglobulin receptor (pIgR) is a key component of the mucosal immune system that mediates epithelial transcytosis of immunoglobulins. High pIgR expression has been reported to correlate with a less aggressive tumour phenotype and an improved prognosis in several human cancer types. Here, we examined the expression and prognostic significance of pIgR in pancreatic and periampullary adenocarcinoma. The study cohort encompasses a consecutive series of 175 patients surgically treated with pancreaticoduodenectomy for pancreatic and periampullary adenocarcinoma in Malmö and Lund University Hospitals, Sweden, between 2001-2011. Tissue microarrays were constructed from primary tumours (n = 175) and paired lymph node metastases (n = 105). A multiplied score was calculated from the fraction and intensity of pIgR staining. Classification and regression tree analysis was used to select the prognostic cut-off. Unadjusted and adjusted hazard ratios (HR) for death and recurrence within 5 years were calculated. pIgR expression could be evaluated in 172/175 (98.3%) primary tumours and in 96/105 (91.4%) lymph node metastases. pIgR expression was significantly down-regulated in lymph node metastases as compared with primary tumours (p = 0.018). Low pIgR expression was significantly associated with poor differentiation grade (p < 0.001), perineural growth (p = 0.027), lymphatic invasion (p = 0.016), vascular invasion (p = 0.033) and infiltration of the peripancreatic fat (p = 0.039). In the entire cohort, low pIgR expression was significantly associated with an impaired 5-year survival (HR = 2.99, 95% confidence interval (CI) 1.71-5.25) and early recurrence (HR = 2.89, 95% CI 1.67-4.98). This association remained significant for survival after adjustment for conventional clinicopathological factors, tumour origin and adjuvant treatment (HR = 1.98, 95% CI 1.10-3.57). These results demonstrate, for the first time, that high tumour-specific pIgR expression signifies a more favourable tumour phenotype and that low expression independently predicts a shorter survival in patients with pancreatic and periampullary cancer. The mechanistic basis for the putative tumour suppressing properties of pIgR in these cancers merits further study.
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| 24. |
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| 25. |
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| 26. |
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| 27. |
- Hultgren, Jakob, 1986-, et al.
(författare)
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Tropical and non-Archimedean Monge-Ampère equations for a class of Calabi-Yau hypersurfaces
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- For a class of maximally degenerate families of Calabi-Yau hypersurfaces of complex projective space, we study associated non-Archimedean and tropical Monge--Ampère equations, taking place on the associated Berkovich space, and the essential skeleton therein, respectively. For a symmetric measure on the skeleton, we prove that the tropical equation admits a unique solution, up to an additive constant. Moreover, the solution to the non-Archimedean equation can be derived from the tropical solution, and is the restriction of a continuous semipositive toric metric on projective space. Together with the work of Yang Li, this implies the weak metric SYZ conjecture on the existence of special Lagrangian fibrations in our setting.
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| 28. |
- Hultgren, Jakob, 1986-, et al.
(författare)
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Tropical and non-Archimedean Monge–Ampère equations for a class of Calabi–Yau hypersurfaces
- 2024
-
Ingår i: Advances in Mathematics. - : Elsevier. - 0001-8708 .- 1090-2082. ; 439
-
Tidskriftsartikel (refereegranskat)abstract
- For a large class of maximally degenerate families of Calabi–Yau hypersurfaces of complex projective space, we study non-Archimedean and tropical Monge–Ampère equations, taking place on the associated Berkovich space, and the essential skeleton therein, respectively. For a symmetric measure on the skeleton, we prove that the tropical equation admits a unique solution, up to an additive constant. Moreover, the solution to the non-Archimedean equation can be derived from the tropical solution, and is the restriction of a continuous semipositive toric metric on projective space. Together with the work of Yang Li, this implies the weak metric SYZ conjecture on the existence of special Lagrangian fibrations in our setting.
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| 29. |
- Hultman, Axel, 1975-, et al.
(författare)
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The topology of the space of matrices of Barvinok rank two
- 2010
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Ingår i: Beiträge zur Algebra und Geometrie. - Lemgo, Germany : Heldermann Verlag. - 0138-4821. ; 51:2, s. 373-390
-
Tidskriftsartikel (refereegranskat)abstract
- The Barvinok rank of a d x n matrix is the minimum number of points in Rd such that the tropical convex hull of the points contains all columns of the matrix. The concept originated in work by Barvinok and others on the travelling salesman problem. Our object of study is the space of real d x n matrices of Barvinok rank two. Let Bd,n denote this space modulo rescaling and translation. We show that Bd,n is a manifold, thereby settling a conjecture due to Develin. In fact, Bd,n is homeomorphic to the quotient of the product of spheres Sd-2 x Sn-2 under the involution which sends each point to its antipode simultaneously in both components. In addition, using discrete Morse theory, we compute the integral homology of Bd,n. Assuming d \ge n, for odd d the homology turns out to be isomorphic to that of Sd-2 x RPn-2. This is true also for even d up to degree d-3, but the two cases differ from degree d-2 and up. The homology computation straightforwardly extends to more general complexes of the form (Sd-2 x X)//Z2, where X is a finite cell complex of dimension at most d-2 admitting a free Z2-action.
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| 30. |
- Höök, Kristina, 1964-, et al.
(författare)
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Embracing First-Person Perspectives in Soma-Based Design
- 2018
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Ingår i: INFORMATICS-BASEL. - : MDPI. - 2227-9709. ; 5:1
-
Tidskriftsartikel (refereegranskat)abstract
- A set of prominent designers embarked on a research journey to explore aesthetics in movement-based design. Here we unpack one of the design sensitivities unique to our practice: a strong first person perspective-where the movements, somatics and aesthetic sensibilities of the designer, design researcher and user are at the forefront. We present an annotated portfolio of design exemplars and a brief introduction to some of the design methods and theory we use, together substantiating and explaining the first-person perspective. At the same time, we show how this felt dimension, despite its subjective nature, is what provides rigor and structure to our design research. Our aim is to assist researchers in soma-based design and designers wanting to consider the multiple facets when designing for the aesthetics of movement. The applications span a large field of designs, including slow introspective, contemplative interactions, arts, dance, health applications, games, work applications and many others.
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| 31. |
- Höök, Kristina, 1964-, et al.
(författare)
-
Move to be moved
- 2016
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Ingår i: Conference on Human Factors in Computing Systems - Proceedings. - New York, NY, USA : Association for Computing Machinery. ; , s. 3301-3308, s. 3301-3308
-
Konferensbidrag (refereegranskat)abstract
- Movement-based design is reaching critical mass in HCI, and we can start to identify strategies, similarities and differences in how it is approached. Similarities may include, for example, a strong first person perspective on design, emphasising movement, somatics and aesthetic sensibilities of the designer, as well as starting from the premise that our bodily ways of being in the world are shaped by the ecologies of people, cultural practices and the artefacts we create and use. Different classes of systems are starting to emerge, such as spurring somaesthetic appreciation processes using biofeedback loops or carefully nudging us to interact with our own movements; engaging us in affective loops where the technology takes on a stronger agency, attempting to pull participants into particular experiences; extending on our senses and perception - even creating new senses through technology; social interactions, engaging us to jointly explore movement or touch; even endowing machines with their own 'somatics', exploring our relationship to technology; as well as engaging in larger political issues around the body, such as gender perspectives, or challenging the mind-body divide.
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| 32. |
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| 33. |
- Johansson, Carloina, et al.
(författare)
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Weather Gods and Fruit Kids - Embodying abstract concepts using tactile feedback and whole body interaction
- 2011
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Ingår i: Connecting computer-supported collaborative learning to policy and practice. - : International Society of the Learning Sciences. - 9780578091525 ; , s. 160-167
-
Konferensbidrag (refereegranskat)abstract
- In this paper we present findings based on the design and study of a game like activity that allows for physical and bodily interaction around abstract concepts like energy and energy consumption in a collaborative learning setting. The game, called Weather Gods and Fruit Kids, uses motion sensing technologies in combination with tactile and audio feedback to create an embodied interactive setting without computer screens. We analyze and discuss the properties of the interactive setting as well as the interactions with and around the system using characteristics such as multiple modalities of response, large space interaction and aspects of focus and attention. The work suggests that alternative pedagogical activities can be created providing new entries to theoretical concepts using an embodied interaction approach. In particular it may support kinesthetic learners in their preference to learn by being physically engaged.
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| 34. |
- Johansson, Louise, et al.
(författare)
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Frequency of apical periodontitis in root-filled teeth restored with post and core : A 5-year retrospective study
- 2024
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Ingår i: Clinical and Experimental Dental Research. - : John Wiley & Sons. - 2057-4347. ; 10:3
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: In conjunction with post placement in root-filled teeth with periapical healthy conditions, root canal retreatment may be performed to improve the seal of the root canal. Whether root canal retreatment for technical reasons (retreatments in teeth without apical periodontitis (AP)) results in lower frequency of AP is unknown.OBJECTIVE: To examine whether there is a difference in frequency of AP between roots with root canals retreated for technical reasons, and roots with root canals not retreated before post placement, with a minimum follow-up of 5 years. Also, to examine changes in root filling quality following root canal retreatment for technical reasons.METHODS: This retrospective study included radiographs of 441 root-filled roots without periapical radiolucencies at baseline, scheduled for post and core treatment. Follow-up data for a minimum of 5 years were available for 305 roots (loss to follow-up 30.8%), 46 of which were retreated for technical reasons. Two calibrated observers assessed root filling sealing quality and length, respectively, and periapical status according to the Periapical Index. The main outcome of the study, AP, was used as the dependent variable and all analyses were performed at root level.RESULTS: The overall frequency of AP at follow-up was 13.8%. The difference in frequency of AP between retreated (4.3%) and nonretreated (15.4%) root canals was not statistically significant, p = .061. Analyses including only roots with preoperatively inadequate root filling quality showed a statistically significant difference (p = .017) between the two treatment groups (2.4% vs. 22.9%).CONCLUSIONS: Root canal retreatment for technical reasons before post and core placement significantly reduces the frequency of AP in roots with inadequate root filling quality.
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| 35. |
- Jonsson, Andreas, 1974-, et al.
(författare)
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Engineering of a femtomolar affinity binding protein to human serum albumin
- 2008
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Ingår i: Protein Engineering Design & Selection. - : Oxford University Press (OUP). - 1741-0126 .- 1741-0134. ; 21:8, s. 515-527
-
Tidskriftsartikel (refereegranskat)abstract
- We describe the development of a novel serum albumin binding protein showing an extremely high affinity (K(D)) for HSA in the femtomolar range. Using a naturally occurring 46-residue three-helix bundle albumin binding domain (ABD) of nanomolar affinity for HSA as template, 15 residues were targeted for a combinatorial protein engineering strategy to identify variants showing improved HSA affinities. Sequencing of 55 unique phage display-selected clones showed a strong bias for wild-type residues at nine positions, whereas various changes were observed at other positions, including charge shifts. Additionally, a few non-designed substitutions appeared. On the basis of the sequences of 12 variants showing high overall binding affinities and slow dissociation rate kinetics, a set of seven 'second generation' variants were constructed. One variant denoted ABD035 displaying wild-type-like secondary structure content and excellent thermal denaturation/renaturation properties showed an apparent affinity for HSA in the range of 50-500 fM, corresponding to several orders of magnitude improvement compared with the wild-type domain. The ABD035 variant also showed an improved affinity toward serum albumin from a number of other species, and a capture experiment involving human serum indicated that the selectivity for serum albumin had not been compromised from the affinity engineering.
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| 36. |
- Jonsson, H. O., et al.
(författare)
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Hit detection in serial femtosecond crystallography using X-ray spectroscopy of plasma emission
- 2017
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Ingår i: IUCrJ. - : International Union of Crystallography (IUCr). - 2052-2525. ; 4, s. 778-784
-
Tidskriftsartikel (refereegranskat)abstract
- Serial femtosecond crystallography is an emerging and promising method for determining protein structures, making use of the ultrafast and bright X-ray pulses from X-ray free-electron lasers. The upcoming X-ray laser sources will produce well above 1000 pulses per second and will pose a new challenge: how to quickly determine successful crystal hits and avoid a high-rate data deluge. Proposed here is a hit-finding scheme based on detecting photons from plasma emission after the sample has been intercepted by the X-ray laser. Plasma emission spectra are simulated for systems exposed to high-intensity femtosecond pulses, for both protein crystals and the liquid carrier systems that are used for sample delivery. The thermal radiation from the glowing plasma gives a strong background in the XUV region that depends on the intensity of the pulse, around the emission lines from light elements (carbon, nitrogen, oxygen). Sample hits can be reliably distinguished from the carrier liquid based on the characteristic emission lines from heavier elements present only in the sample, such as sulfur. For buffer systems with sulfur present, selenomethionine substitution is suggested, where the selenium emission lines could be used both as an indication of a hit and as an aid in phasing and structural reconstruction of the protein.
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| 37. |
- Jonsson, Jakob
(författare)
-
3-torsion in the Homology of Complexes of Graphs of Bounded Degree
- 2013
-
Ingår i: Canadian Journal of Mathematics. - 0008-414X .- 1496-4279. ; 65:4, s. 843-862
-
Tidskriftsartikel (refereegranskat)abstract
- For delta >= 1 and n >= 1, consider the simplicial complex of graphs on n vertices in which each vertex has degree at most delta; we identify a given graph with its edge set and admit one loop at each vertex. This complex is of some importance in the theory of semigroup algebras. When delta = 1, we obtain the matching complex, for which it is known that there is 3-torsion in degree d of the homology whenever (n - 4)/3 <= d <= (n - 6)/2. This paper establishes similar bounds for delta >= 2. Specifically, there is 3-torsion in degree d whenever (3 delta - 1)n - 8/6 <= d <= delta(n - 1) - 4/2. The procedure for detecting torsion is to construct an explicit cycle z that is easily seen to have the property that 3z is a boundary. Defining a homomorphism that sends z to a non-boundary element in the chain complex of a certain matching complex, we obtain that z itself is a non-boundary. In particular, the homology class of z has order 3.
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| 38. |
- Jonsson, Jakob, et al.
(författare)
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A spherical initial ideal for Pfaffians
- 2007
-
Ingår i: Illinois Journal of Mathematics. - : Duke University Press. - 0019-2082 .- 1945-6581. ; 51:4, s. 1397-1407
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Tidskriftsartikel (refereegranskat)abstract
- We determine a term order on the monomials in the variables X-ij, 1 <= i <= j <= n, such that corresponding initial ideal of the ideal of Pfaffians of degree r of a generic n by n skew-symmetric matrix is the Stanley-Reisner ideal of a join of a simplicial sphere and a simplex. Moreover, we demonstrate that the Pfaffians of the 2r by 2r skew-symmetric submatrices form a, Grobner basis for the given term order. The same methods and similar term orders as for the Pfaffians also yield squarefree initial ideals for certain determinantal ideals. Yet, in contrast to the case of Pfaffians, the corresponding simplicial complexes are balls that do not decompose into a join as above.
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| 39. |
- Jonsson, Jakob
(författare)
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Certain Homology Cycles of the Independence Complex of Grids
- 2010
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Ingår i: Discrete & Computational Geometry. - : Springer Science and Business Media LLC. - 0179-5376 .- 1432-0444. ; 43:4, s. 927-950
-
Tidskriftsartikel (refereegranskat)abstract
- Let G be an infinite graph such that the automorphism group of G contains a subgroup K congruent to Z(d) with the property that G/K is finite. We examine the homology of the independence complex Sigma(G/I) of G/I for subgroups I of K of full rank, focusing on the case that G is the square, triangular, or hexagonal grid. Specifically, we look for a certain kind of homology cycles that we refer to as "cross-cycles," the rationale for the terminology being that they are fundamental cycles of the boundary complex of some cross-polytope. For the special cases just mentioned, we determine the set Q(G, K) of rational numbers r such that there is a group I with the property that Sigma(G/I) contains cross-cycles of degree exactly r . |G/I| - 1; |G/I| denotes the size of the vertex set of G/I. In each of the three cases, Q( G, K) turns out to be an interval of the form [a, b] boolean AND Q = {r is an element of Q : a <= r <= b}. For example, for the square grid, we obtain the interval [1/5, 1/4] boolean AND Q.
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| 40. |
- Jonsson, Jakob, et al.
(författare)
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COMPLEXES OF INJECTIVE WORDS AND THEIR COMMUTATION CLASSES
- 2009
-
Ingår i: Pacific Journal of Mathematics. - : Mathematical Sciences Publishers. - 0030-8730 .- 1945-5844. ; 243:2, s. 313-329
-
Tidskriftsartikel (refereegranskat)abstract
- Let S be a finite alphabet. An injective word over S is a word over S such that each letter in S appears at most once in the word. For an abstract simplicial complex Delta, let Gamma(Delta) be the Boolean cell complex whose cells are indexed by all injective words over the sets forming the faces of Delta. The boundary of a cell indexed by a given word w consists of those cells that are indexed by subwords of w. For a partial order P on S, we study the subcomplex Gamma(Delta, P) of Gamma(Delta) consisting of those cells that are indexed by words whose letters are arranged in increasing order with respect to some linear extension of the order P. For a graph G = (S, E) on vertex set S and a word w over S, let [w] be the class of all words that we can obtain from w via a sequence of commutations ss' -> s's s such that {s, s'} g is not an edge in E. We study the Boolean cell complex Gamma/G(Delta) whose cells are indexed by commutation classes [w] of words indexing cells in Gamma(Delta). We prove: If Delta is shellable then so are Gamma(Delta, P) and Gamma/G(Delta). If Delta is Cohen-Macaulay (respectively sequentially Cohen-Macaulay) then so are Gamma(Delta, P) and Gamma/G(Delta). The complex Gamma(Delta) is partitionable. Our work generalizes work by Farmer and by Bjorner and Wachs on the complex of all injective words.
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| 41. |
- Jonsson, Jakob
(författare)
-
Exact sequences for the homology of the matching complex
- 2008
-
Ingår i: Journal of combinatorial theory. Series A (Print). - : Elsevier BV. - 0097-3165 .- 1096-0899. ; 115:8, s. 1504-1526
-
Tidskriftsartikel (refereegranskat)abstract
- Building on work by Bouc and by Shareshian and Wachs, we provide a toolbox of long exact sequences for the reduced simplicial homology of the matching complex M., which is the simplicial complex of matchings in the complete graph K-n. Combining these sequences in different ways, we prove several results about the 3-torsion part of the homology of M, First, we demonstrate that there is nonvanishing 3-torsion in (H) over bar (d)(M-n : Z) whenever v(n) <= d <= [n-6/2], where v(n) =[n-4/3]. By results due to Bouc and to Shareshian and Wachs, (H) over bar (d)(M-n : Z) is a nontrivial elementary 3-group for almost all n and the bottom nonvanishing homology group of M. for all n 0 2. Second, we prove that (H) over bar (d)(M-n : Z) is a nontrivial 3-group whenever v(n) <= d <= [2n-9/5]. Third, for each k >= 0, we show that there is a polynomial f(k)(r) of degree 3k such that the dimension of (H) over bar (k-1+r) (M2k+1+3r:Z(3)), viewed as a vector space over Z(3), is at most f(k)(r) for all r >= k + 2.
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| 42. |
- Jonsson, Jakob
(författare)
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Five-torsion in the homology of the matching complex on 14 vertices
- 2009
-
Ingår i: Journal of Algebraic Combinatorics. - : Springer Science and Business Media LLC. - 0925-9899 .- 1572-9192. ; 29:1, s. 81-90
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Tidskriftsartikel (refereegranskat)abstract
- J.L. Andersen proved that there is 5-torsion in the bottom nonvanishing homology group of the simplicial complex of graphs of degree at most two on seven vertices. We use this result to demonstrate that there is 5-torsion also in the bottom nonvanishing homology group of the matching complex M-14 on 14 vertices. Combining our observation with results due to Bouc and to Shareshian and Wachs, we conclude that the case n = 14 is exceptional; for all other n, the torsion subgroup of the bottom nonvanishing homology group has exponent three or is zero. The possibility remains that there is other torsion than 3-torsion in higher-degree homology groups of M-n when n = 13 and n not equal 14.
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| 43. |
- Jonsson, Jakob, et al.
(författare)
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GamTest : Psychometric Evaluation and the Role of Emotions in an Online Self-Test for Gambling Behavior
- 2017
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Ingår i: Journal of Gambling Studies. - : Springer Science and Business Media LLC. - 1050-5350 .- 1573-3602. ; 33:2, s. 505-523
-
Tidskriftsartikel (refereegranskat)abstract
- Recent increases in the number of online gambling sites have made gambling more available, which may contribute to an increase in gambling problems. At the same time, online gambling provides opportunities to introduce measures intended to prevent problem gambling. GamTest is an online test of gambling behavior that provides information that can be used to give players individualized feedback and recommendations for action. The aim of this study is to explore the dimensionality of GamTest and validate it against the Problem Gambling Severity Index (PGSI) and the gambler's own perceived problems. A recent psychometric approach, exploratory structural equation modeling (ESEM) is used. Well-defined constructs are identified in a two-step procedure fitting a traditional exploratory factor analysis model as well as a so-called bifactor model. Using data collected at four Nordic gambling sites in the autumn of 2009 (n = 10,402), the GamTest ESEM analyses indicate high correspondence with the players' own understanding of their problems and with the PGSI, a validated measure of problem gambling. We conclude that GamTest captures five dimensions of problematic gambling (i.e., overconsumption of money and time, and monetary, social and emotional negative consequences) with high reliability, and that the bifactor approach, composed of a general factor and specific residual factors, reproduces all these factors except one, the negative consequences emotional factor, which contributes to the dominant part of the general factor. The results underscore the importance of tailoring feedback and support to online gamblers with a particular focus on how to handle emotions in relation to their gambling behavior.
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| 44. |
- Jonsson, Jakob
(författare)
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Generalized triangulations and diagonal-free subsets of stack polyrominoes
- 2005
-
Ingår i: Journal of combinatorial theory. Series A (Print). - : Elsevier BV. - 0097-3165 .- 1096-0899. ; 112:1, s. 117-142
-
Tidskriftsartikel (refereegranskat)abstract
- For n >= 3, let Omega(n) be the set of line segments between vertices in a convex n-gon. For j >= 1, a j-crossing is a set of j distinct and mutually intersecting line segments from Q,, such that all 2j endpoints are distinct. For k >= 1, let Delta(n,k) be the simplicial complex of subsets of Omega(n) not containing any (k + 1)-crossing. For example, Delta(n.1) has one maximal set for each triangulation of the n-gon. Dress, Koolen, and Moulton were able to prove that all maximal sets in Delta(n,k) have the same number k(2n - 2k - 1) of line segments. We demonstrate that the number of such maximal sets is counted by a k x k determinant of Catalan numbers. By the work of Desainte-Catherine and Viennot, this determinant is known to count quite a few other objects including fans of non-crossing Dyck paths. We generalize our result to a larger class of simplicial complexes including some of the complexes appearing in the work of Herzog and Trung, on determinantal ideals.
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| 45. |
- Jonsson, Jakob
(författare)
-
Hard squares with negative activity and rhombus tilings of the plane
- 2006
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Ingår i: The Electronic Journal of Combinatorics. - : The Electronic Journal of Combinatorics. - 1097-1440 .- 1077-8926. ; 13:1
-
Tidskriftsartikel (refereegranskat)abstract
- Let S-m,S-n be the graph on the vertex set Z(m) x Z(n) in which there is an edge between (a, b) and (c, d) if and only if either (a, b) = (c, d +/- 1) or (a, b) (c +/- 1, d) modulo (m, n). We present a formula for the Euler characteristic of the simplicial complex Sigma(m,n) of independent sets in S-m,S-n. In particular, we show that the unreduced Euler characteristic of Sigma(m,n) vanishes whenever m and n are coprime, thereby settling a conjecture in statistical mechanics due to Fendley, Schoutens and van Eerten. For general m and n, we relate the Euler characteristic of Sigma(m,n) to certain periodic rhombus tilings of the plane. Using this correspondence, we settle another conjecture due to Fendley et al., which states that all roots of det(x(I) - T-m) are roots of unity, where T-m is a certain transfer matrix associated to {Sigma(m,n) : n >= 1}. In the language of statistical mechanics, the reduced Euler characteristic of Sigma(m,n) coincides with minus the partition function of the corresponding hard square model with activity -1.
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| 46. |
- Jonsson, Jakob
(författare)
-
Hard Squares with Negative Activity on Cylinders with Odd Circumference
- 2009
-
Ingår i: The Electronic Journal of Combinatorics. - 1097-1440 .- 1077-8926. ; 16:2
-
Tidskriftsartikel (refereegranskat)abstract
- Let C-m,C-n be the graph on the vertex set {1, ..., m} x {0, ..., n-1} in which there is an edge between (a, b) and (c, d) if and only if either (a, b) = (c, d +/- 1) or (a, b) = (c +/- 1, d), where the second index is computed modulo n. One may view C-m,C-n as a unit square grid on a cylinder with circumference n units. For odd n, we prove that the Euler characteristic of the simplicial complex Sigma(m,n) of independent sets in C-m,C-n is either 2 or -1, depending on whether or not gcd(m-1, n) is divisble by 3. The proof relies heavily on previous work due to Thapper, who reduced the problem of computing the Euler characteristic of Sigma(m,n) to that of analyzing a certain subfamily of sets with attractive properties. The situation for even n remains unclear. In the language of statistical mechanics, the reduced Euler characteristic of Sigma(m,n) coincides with minus the partition function of the corresponding hard square model with activity -1.
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| 47. |
- Jonsson, Jakob
(författare)
-
Hom complexes of set systems
- 2013
-
Ingår i: The Electronic Journal of Combinatorics. - : The Electronic Journal of Combinatorics. - 1097-1440 .- 1077-8926. ; 20:1, s. P4-
-
Tidskriftsartikel (refereegranskat)abstract
- A set system is a pair S = (V (S), Delta(S)), where Delta(S) is a family of subsets of the set V(S). We refer to the members of Delta(S) as the stable sets of S. A homomorphism between two set systems S and T is a map f : V (S) -> V(T) such that the preimage under f of every stable set of T is a stable set of S. Inspired by a recent generalization due to Engstrom of Lovasz's Hom complex construction, the author associates a cell complex Hom(S, T) to any two finite set systems S and T. The main goal of the paper is to examine basic topological and homological properties of this cell complex for various pairs of set systems.
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| 48. |
- Jonsson, Jakob, 1968-, et al.
(författare)
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In search of lower risk gambling levels using behavioral data from a gambling monopolist
- 2022
-
Ingår i: Journal of Behavioral Addictions. - : Akademiai Kiado Zrt.. - 2062-5871 .- 2063-5303. ; 11:3, s. 890-899
-
Tidskriftsartikel (refereegranskat)abstract
- Background and aims: Lower-risk recommendations for avoiding gambling harm have been developed as a primary prevention measure, using self-reported prevalence survey data. The aim of this study was to conduct similar analyses using gambling company player data.Methods: The sample (N = 35,753) were Norsk Tipping website customers. Gambling indicators were frequency, expenditure, duration, number of gambling formats and wager. Harm indicators (financial. social, emotional, harms in two or more areas) were derived from the GamTest self-assessment instrument. Receiver operating characteristics (ROC) curves were performed separately for each of the five gambling indicators for each of the four harm indicators.Results: ROC areas under the curve were between 0.55 and 0.68. Suggested monthly lower-risk limits were less than 8.7 days, expenditure less than 54 €, duration less than 72–83 min, number of gambling formats less than 3 and wager less than 118–140€. Most risk curves showed a rather stable harm level up to a certain point, from which the increase in harm was fairly linear.Discussion: The suggested lower-risk limits in the present study are higher than limits based on prevalence studies. There was a significant number of gamblers (5–10%) experiencing harm at gambling levels well below the suggested cut-offs and the risk increase at certain consumption levels.Conclusions: Risk of harm occurs at all levels of gambling involvement within the specific gambling commercial environment assessed in an increasingly available gambling market where most people gamble in multiple commercial environments, minimizing harm is important for all customers.
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| 49. |
- Jonsson, Jakob, et al.
(författare)
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Measuring Gambling Reinforcers, Over Consumption and Fallacies : The Psychometric Properties and Predictive Validity of the Jonsson-Abbott Scale
- 2017
-
Ingår i: Frontiers in Psychology. - : Frontiers Media SA. - 1664-1078. ; 8
-
Tidskriftsartikel (refereegranskat)abstract
- Traditionally, gambling and problem gambling research relies on cross-sectional and retrospective designs. This has compromised identification of temporal relationships and causal inference. To overcome these problems a new questionnaire, the Jonsson-Abbott Scale (JAS), was developed and used in a large, prospective, general population study, The Swedish Longitudinal Gambling Study (Swelogs). The JAS has 11 items and seeks to identify early indicators, examine relationships between indicators and assess their capacity to predict future problem progression. The aims of the study were to examine psychometric properties of the JAS (internal consistency and dimensionality) and predictive validity with respect to increased gambling risk and problem gambling onset. The results are based on repeated interviews with 3818 participants. The response rate from the initial baseline wave was 74%. The original sample consisted of a random, stratified selection from the Swedish population register aged between 16 and 84. The results indicate an acceptable fit of a three-factor solution in a confirmatory factor analysis with ‘Over consumption,’ ‘Gambling fallacies,’ and ‘Reinforcers’ as factors. Reinforcers, Over consumption and Gambling fallacies were significant predictors of gambling risk potential and Gambling fallacies and Over consumption were significant predictors of problem gambling onset (incident cases) at 12 month follow up. When controlled for risk potential measured at baseline, the predictor Over consumption was not significant for gambling risk potential at follow up. For incident cases, Gambling fallacies and Over consumption remained significant when controlled for risk potential. Implications of the results for the development of problem gambling, early detection, prevention, and future research are discussed.
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| 50. |
- Jonsson, Jakob
(författare)
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More Torsion in the Homology of the Matching Complex
- 2010
-
Ingår i: Experimental Mathematics. - : Informa UK Limited. - 1058-6458 .- 1944-950X. ; 19:3, s. 363-383
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Tidskriftsartikel (refereegranskat)abstract
- A matching on a set X is a collection of pairwise disjoint subsets of X of size two Using computers, we analyze the integral homology of the matching complex M, which is the simplicial complex of matchings on the set {1, ,n} The main result is the detection of elements of order p in the homology for p is an element of {5, 7, 11, 13} Specifically, we show that there are elements of order 5 in the homology of M-n for n >= 18 and for n is an element of {14, 16} The only previously known value was n = 14, and in this particular case we have a new computer-free proof Moreover, we show that there are elements of order 7 in the homology of M-n for all odd a between 23 and 41 and for n = 30 In addition, there are elements of order 11 in the homology of M-47 and elements of order 13 in the homology of M-62 Finally, we compute the ranks of the Sylow 3- and 5-subgroups of the torsion part of (H) over tilde (d)(M-n, Z) for 13 <= n <= 16, a complete description of the homology already exists for n <= 12 To prove the results, we use a representation-theoretic approach, examining subcomplexes of the chain complex of M-n obtained by letting certain groups act on the chain complex.
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