959 resultados para Sund, Lars
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Helsingfors : A.W. Gröndahl & A.C. Öhman 1845 : Dresden, Adler u. Dietze
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The Annonaceae includes cultivated species of economic interest and represents an important source of information for better understanding the evolution of tropical rainforests. In phylogenetic analyses of DNA sequence data that are used to address evolutionary questions, it is imperative to use appropriate statistical models. Annonaceae are cases in point: Two sister clades, the subfamilies Annonoideae and Malmeoideae, contain the majority of Annonaceae species diversity. The Annonoideae generally show a greater degree of sequence divergence compared to the Malmeoideae, resulting in stark differences in branch lengths in phylogenetic trees. Uncertainty in how to interpret and analyse these differences has led to inconsistent results when estimating the ages of clades in Annonaceae using molecular dating techniques. We ask whether these differences may be attributed to inappropriate modelling assumptions in the phylogenetic analyses. Specifically, we test for (clade-specific) differences in rates of non-synonymous and synonymous substitutions. A high ratio of nonsynonymous to synonymous substitutions may lead to similarity of DNA sequences due to convergence instead of common ancestry, and as a result confound phylogenetic analyses. We use a dataset of three chloroplast genes (rbcL, matK, ndhF) for 129 species representative of the family. We find that differences in branch lengths between major clades are not attributable to different rates of non-synonymous and synonymous substitutions. The differences in evolutionary rate between the major clades of Annonaceae pose a challenge for current molecular dating techniques that should be seen as a warning for the interpretation of such results in other organisms.
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BACKGROUND: Artemisinin-resistant Plasmodium falciparum has emerged in the Greater Mekong sub-region and poses a major global public health threat. Slow parasite clearance is a key clinical manifestation of reduced susceptibility to artemisinin. This study was designed to establish the baseline values for clearance in patients from Sub-Saharan African countries with uncomplicated malaria treated with artemisinin-based combination therapies (ACTs). METHODS: A literature review in PubMed was conducted in March 2013 to identify all prospective clinical trials (uncontrolled trials, controlled trials and randomized controlled trials), including ACTs conducted in Sub-Saharan Africa, between 1960 and 2012. Individual patient data from these studies were shared with the WorldWide Antimalarial Resistance Network (WWARN) and pooled using an a priori statistical analytical plan. Factors affecting early parasitological response were investigated using logistic regression with study sites fitted as a random effect. The risk of bias in included studies was evaluated based on study design, methodology and missing data. RESULTS: In total, 29,493 patients from 84 clinical trials were included in the analysis, treated with artemether-lumefantrine (n = 13,664), artesunate-amodiaquine (n = 11,337) and dihydroartemisinin-piperaquine (n = 4,492). The overall parasite clearance rate was rapid. The parasite positivity rate (PPR) decreased from 59.7 % (95 % CI: 54.5-64.9) on day 1 to 6.7 % (95 % CI: 4.8-8.7) on day 2 and 0.9 % (95 % CI: 0.5-1.2) on day 3. The 95th percentile of observed day 3 PPR was 5.3 %. Independent risk factors predictive of day 3 positivity were: high baseline parasitaemia (adjusted odds ratio (AOR) = 1.16 (95 % CI: 1.08-1.25); per 2-fold increase in parasite density, P <0.001); fever (>37.5 °C) (AOR = 1.50 (95 % CI: 1.06-2.13), P = 0.022); severe anaemia (AOR = 2.04 (95 % CI: 1.21-3.44), P = 0.008); areas of low/moderate transmission setting (AOR = 2.71 (95 % CI: 1.38-5.36), P = 0.004); and treatment with the loose formulation of artesunate-amodiaquine (AOR = 2.27 (95 % CI: 1.14-4.51), P = 0.020, compared to dihydroartemisinin-piperaquine). CONCLUSIONS: The three ACTs assessed in this analysis continue to achieve rapid early parasitological clearance across the sites assessed in Sub-Saharan Africa. A threshold of 5 % day 3 parasite positivity from a minimum sample size of 50 patients provides a more sensitive benchmark in Sub-Saharan Africa compared to the current recommended threshold of 10 % to trigger further investigation of artemisinin susceptibility.
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Le traitement de radiochirurgie par Gamma Knife (GK) est utilisé de plus en plus souvent comme une alternative à la microchirurgie conventionnelle pour le traitement des pathologies neurochirurgicales intracrâniennes. Il s'agit d'irradier en dose unique et à haute énergie, en condition stéréotaxique et à l'aide d'une imagerie multimodale (imagerie par résonance magnétique [IRM], tomodensitométrie et éventuellement artériographie). Le GK a été inventé par le neurochirurgien suédois Lars Leksell, qui a réalisé le premier ciblage du nerf trijumeau en 1951, sur la base d'une radiographie standard. Depuis, les progrès de l'informatique et de la robotique ont permis d'améliorer la technique de radiochirurgie qui s'effectue actuellement soit par accélérateur linéaire de particules monté sur un bras robotisé (Novalis®, Cyberknife®), soit par collimation de près de 192 sources fixes (GK). La principale indication radiochirurgicale dans le traitement de la douleur est la névralgie du nerf trijumeau. Les autres indications, plus rares, sont la névralgie du nerf glossopharyngien, l'algie vasculaire de la face, ainsi qu'un traitement de la douleur d'origine cancéreuse par hypophysiolyse. Gamma Knife surgery (GKS) is widely used as an alternative to open microsurgical procedures as noninvasive treatment of many intracranial conditions. It consists of delivering a single dose of high energy in stereotactic conditions, and with the help of a multimodal imaging (e.g., magnetic resonance imaging [MRI], computer tomography, and eventually angiography). The Gamma Knife (GK) was invented by the Swedish neurosurgeon Lars Leksell who was the first to treat a trigeminal neuralgia sufferer in 1951 using an orthogonal X-ray tube. Since then, the progresses made both in the field of informatics and robotics have allowed to improve the radiosurgical technique, which is currently performed either by a linear accelerator of particles mounted on a robotized arm (Novalis®, Cyberknife®), or by collimation of 192 fixed Co-60 sources (GK). The main indication of GKS in the treatment of pain is trigeminal neuralgia. The other indications, less frequent, are: glossopharyngeal neuralgia, cluster headache, and hypophysiolyse for cancer pain.
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Samlingen med signum HB VIb finns vid huvudbiblioteket och innehåller litteratur om nationalekonomi till och med år 1999. Bankhistoriker ingår i denna samling. Vid Institutionen för samhällsekonomi och statistik finns dessutom en samling nationalekonomiskt litteratur. Nationalekonomisk litteratur har ingått i bokdonationer såväl från hemlandet som från Sverige. Bland donatorerna kan nämnas Gösta Söderholm, Lars Wasastjerna, J.V.Tallqvist och Tor von Wright. Samlingen har kompletterats med friexemplar som erhållits från 1919. Den nationalekonomiska litteraturen söks i Alma med sökfunktionen Signum och söktermen HB VIb. En del litteratur tryckt före 1980 skall sökas manuellt i huvudbibliotekets systematiska kortkatalog, men retroaktiv inmatning i Alma av litteratur tryckt mellan 1830 och 1979 pågår. Från och med år 2000 ingår den nationalekonomiska litteraturen vid huvudbiblioteket i en numerus currens-samling.
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Fungi and bacteria are key agents in plant litter decomposition in freshwater ecosystems. However, the specific roles of these two groups and their interactions during the decomposition process are unclear. We compared the growth and patterns of degradativeenzymes expressed by communities of bacteria and fungi grown separately and in coexistence on Phragmites leaves. The two groups displayed both synergistic and antagonistic interactions. Bacteria grew better together with fungi than alone. In addition, there was a negative effect of bacteria on fungi, which appeared to be caused by suppression of fungal growth and biomass accrual rather than specifically affecting enzyme activity. Fungi growing alone had a high capacity for the decomposition of plant polymers such as lignin, cellulose, and hemicellulose. In contrast, enzyme activities were in general low when bacteria grew alone, and the activity of key enzymes in the degradation of lignin and cellulose (phenol oxidase and cellobiohydrolase) was undetectable in the bacteria-only treatment. Still, biomass-specific activities of most enzymes were higher in bacteria than in fungi. The low total activity and growth of bacteria in the absence of fungi in spite of apparent high enzymatic efficiency during the degradation of many substrates suggest that fungi provide the bacteria with resources that the bacteria were not able to acquire on their own, most probably intermediate decomposition products released by fungi that could be used by bacteria
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We study how the combination of long and short laser pulses can be used to induce torsion in an axially chiral biphenyl derivative (3,5-difluoro-3 ,5 -dibromo-4 -cyanobiphenyl). A long, with respect to the molecular rotational periods, elliptically polarized laser pulse produces 3D alignment of the molecules, and a linearly polarized short pulse initiates torsion about the stereogenic axis. The torsional motion is monitored in real-time by measuring the dihedral angle using femtosecond time-resolved Coulomb explosion imaging. Within the first 4 picoseconds (ps), torsion occurs with a period of 1.25 ps and an amplitude of 3◦ in excellent agreement with theoretical calculations. At larger times, the quantum states of the molecules describing the torsional motion dephase and an almost isotropic distribution of the dihedral angle is measured.We demonstrate an original application of covariance analysis of two-dimensional ion images to reveal strong correlations between specific ejected ionic fragments from Coulomb explosion. This technique strengthens our interpretation of the experimental data