| 1. |
- Aad, G., et al.
(författare)
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Readiness of the ATLAS Tile Calorimeter for LHC collisions
- 2010
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 70:4, s. 1193-1236
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Tidskriftsartikel (refereegranskat)abstract
- The Tile hadronic calorimeter of the ATLAS detector has undergone extensive testing in the experimental hall since its installation in late 2005. The readout, control and calibration systems have been fully operational since 2007 and the detector has successfully collected data from the LHC single beams in 2008 and first collisions in 2009. This paper gives an overview of the Tile Calorimeter performance as measured using random triggers, calibration data, data from cosmic ray muons and single beam data. The detector operation status, noise characteristics and performance of the calibration systems are presented, as well as the validation of the timing and energy calibration carried out with minimum ionising cosmic ray muons data. The calibration systems' precision is well below the design value of 1%. The determination of the global energy scale was performed with an uncertainty of 4%.
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| 2. |
- Aad, G., et al.
(författare)
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Studies of the performance of the ATLAS detector using cosmic-ray muons
- 2011
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 71:3
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Tidskriftsartikel (refereegranskat)abstract
- Muons from cosmic-ray interactions in the atmosphere provide a high-statistics source of particles that can be used to study the performance and calibration of the ATLAS detector. Cosmic-ray muons can penetrate to the cavern and deposit energy in all detector subsystems. Such events have played an important role in the commissioning of the detector since the start of the installation phase in 2005 and were particularly important for understanding the detector performance in the time prior to the arrival of the first LHC beams. Global cosmic-ray runs were undertaken in both 2008 and 2009 and these data have been used through to the early phases of collision data-taking as a tool for calibration, alignment and detector monitoring. These large datasets have also been used for detector performance studies, including investigations that rely on the combined performance of different subsystems. This paper presents the results of performance studies related to combined tracking, lepton identification and the reconstruction of jets and missing transverse energy. Results are compared to expectations based on a cosmic-ray event generator and a full simulation of the detector response.
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| 3. |
- Aad, G., et al.
(författare)
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The ATLAS Inner Detector commissioning and calibration
- 2010
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 70:3, s. 787-821
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Tidskriftsartikel (refereegranskat)abstract
- The ATLAS Inner Detector is a composite tracking system consisting of silicon pixels, silicon strips and straw tubes in a 2 T magnetic field. Its installation was completed in August 2008 and the detector took part in data-taking with single LHC beams and cosmic rays. The initial detector operation, hardware commissioning and in-situ calibrations are described. Tracking performance has been measured with 7.6 million cosmic-ray events, collected using a tracking trigger and reconstructed with modular pattern-recognition and fitting software. The intrinsic hit efficiency and tracking trigger efficiencies are close to 100%. Lorentz angle measurements for both electrons and holes, specific energy-loss calibration and transition radiation turn-on measurements have been performed. Different alignment techniques have been used to reconstruct the detector geometry. After the initial alignment, a transverse impact parameter resolution of 22.1 +/- 0.9 mu m and a relative momentum resolution sigma (p) /p=(4.83 +/- 0.16)x10(-4) GeV(-1)xp (T) have been measured for high momentum tracks.
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| 4. |
- Aad, G., et al.
(författare)
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The ATLAS Simulation Infrastructure
- 2010
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 70:3, s. 823-874
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Tidskriftsartikel (refereegranskat)abstract
- The simulation software for the ATLAS Experiment at the Large Hadron Collider is being used for large-scale production of events on the LHC Computing Grid. This simulation requires many components, from the generators that simulate particle collisions, through packages simulating the response of the various detectors and triggers. All of these components come together under the ATLAS simulation infrastructure. In this paper, that infrastructure is discussed, including that supporting the detector description, interfacing the event generation, and combining the GEANT4 simulation of the response of the individual detectors. Also described are the tools allowing the software validation, performance testing, and the validation of the simulated output against known physics processes.
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| 5. |
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| 6. |
- Nystedt, Björn, et al.
(författare)
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The Norway spruce genome sequence and conifer genome evolution
- 2013
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Ingår i: Nature. - : Nature Publishing Group. - 0028-0836 .- 1476-4687. ; 497:7451, s. 579-584
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Tidskriftsartikel (refereegranskat)abstract
- Conifers have dominated forests for more than 200 million years and are of huge ecological and economic importance. Here we present the draft assembly of the 20-gigabase genome of Norway spruce (Picea abies), the first available for any gymnosperm. The number of well-supported genes (28,354) is similar to the >100 times smaller genome of Arabidopsis thaliana, and there is no evidence of a recent whole-genome duplication in the gymnosperm lineage. Instead, the large genome size seems to result from the slow and steady accumulation of a diverse set of long-terminal repeat transposable elements, possibly owing to the lack of an efficient elimination mechanism. Comparative sequencing of Pinus sylvestris, Abies sibirica, Juniperus communis, Taxus baccata and Gnetum gnemon reveals that the transposable element diversity is shared among extant conifers. Expression of 24-nucleotide small RNAs, previously implicated in transposable element silencing, is tissue-specific and much lower than in other plants. We further identify numerous long (>10,000 base pairs) introns, gene-like fragments, uncharacterized long non-coding RNAs and short RNAs. This opens up new genomic avenues for conifer forestry and breeding.
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| 7. |
- Aad, G., et al.
(författare)
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Commissioning of the ATLAS Muon Spectrometer with cosmic rays
- 2010
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 70:3, s. 875-916
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Tidskriftsartikel (refereegranskat)abstract
- The ATLAS detector at the Large Hadron Collider has collected several hundred million cosmic ray events during 2008 and 2009. These data were used to commission the Muon Spectrometer and to study the performance of the trigger and tracking chambers, their alignment, the detector control system, the data acquisition and the analysis programs. We present the performance in the relevant parameters that determine the quality of the muon measurement. We discuss the single element efficiency, resolution and noise rates, the calibration method of the detector response and of the alignment system, the track reconstruction efficiency and the momentum measurement. The results show that the detector is close to the design performance and that the Muon Spectrometer is ready to detect muons produced in high energy proton-proton collisions.
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| 8. |
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| 9. |
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| 10. |
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| 11. |
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| 12. |
- Adler, Jan-Olof, et al.
(författare)
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A broad range tagging spectrometer for the MAX-laboratory
- 1997
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - 0167-5087. ; 388:1-2, s. 17-26
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Tidskriftsartikel (refereegranskat)abstract
- A broad range tagging spectrometer together with a new beam transport system for photonuclear experiments at the MAX-laboratory in Lund is described. The spectrometer consists of a quadrupole followed by an Elbek-type dipole and has a large momentum acceptance. It can produce both polarized and unpolarized tagged photons in the energy range 10–80 MeV with an energy resolution of about 300 keV.
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| 13. |
- Allard, Anna, et al.
(författare)
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Småbiotopsuppföljning i NILS år 2008
- 2009
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Denna rapport presenterar resultat för mängden av småbiotoper vid åkermark i det svenska landskapet. Analyserna görs på uppdrag av Jordbruksverket, som underlag för bl.a. utvärderingen av miljökvalitetsmålet Ett rikt odlingslandskap. Särskilda rutiner har tagits fram för att aggregera olika variabler för att välja ut de småbiotoper som uppfyller de krav som Jordbruksverket har ställt upp, ur den befintliga databasen. Urvalet av småbiotoper är anpassat för att överensstämma med det urval av objekt som ingår i det s.k. KULT-stödet (miljöersättning till lantbrukare för skötsel av värdefulla natur- och kulturmiljöer) inom Jordbruksverkets Landsbygdsprogram. Arbetet har utförts vid institutionen för skoglig resurshushållning, Sveriges lantbruks-universitet, Umeå. Resultaten baseras på data från flygbildsinventeringen inom det nationella miljöövervakningsprogrammet NILS (Nationell Inventering av Landskapet i Sverige) vilket följer tillstånd och förändringar i det svenska landskapet och hur dessa påverkar förutsättningarna för den biologiska mångfalden. NILS finansieras av Naturvårdsverket, och ingår där i programområde Landskap. Ett viktigt syfte med programmet är att följa upp de nationella miljökvalitetsmålen för olika naturtyper och fungera som underlag för att se om genomförda policybeslut och miljövårdsåtgärder leder till önskade förbättringar
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| 14. |
- Andersson, Anders, et al.
(författare)
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A transcriptional timetable of autumn senescence
- 2004
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Ingår i: Genome Biology. - : Springer Science and Business Media LLC. - 1465-6906 .- 1474-760X. ; 5:4, s. R24-
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Tidskriftsartikel (refereegranskat)abstract
- Background We have developed genomic tools to allow the genus Populus (aspens and cottonwoods) to be exploited as a full-featured model for investigating fundamental aspects of tree biology. We have undertaken large-scale expressed sequence tag (EST) sequencing programs and created Populus microarrays with significant gene coverage. One of the important aspects of plant biology that cannot be studied in annual plants is the gene activity involved in the induction of autumn leaf senescence. Results On the basis of 36,354 Populus ESTs, obtained from seven cDNA libraries, we have created a DNA microarray consisting of 13,490 clones, spotted in duplicate. Of these clones, 12,376 (92%) were confirmed by resequencing and all sequences were annotated and functionally classified. Here we have used the microarray to study transcript abundance in leaves of a free-growing aspen tree (Populus tremula) in northern Sweden during natural autumn senescence. Of the 13,490 spotted clones, 3,792 represented genes with significant expression in all leaf samples from the seven studied dates. Conclusions We observed a major shift in gene expression, coinciding with massive chlorophyll degradation, that reflected a shift from photosynthetic competence to energy generation by mitochondrial respiration, oxidation of fatty acids and nutrient mobilization. Autumn senescence had much in common with senescence in annual plants; for example many proteases were induced. We also found evidence for increased transcriptional activity before the appearance of visible signs of senescence, presumably preparing the leaf for degradation of its components.
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| 15. |
- Andreou, Dimitrios, et al.
(författare)
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Cardiac left ventricular ejection fraction in men and women with schizophrenia on long-term antipsychotic treatment
- 2020
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Ingår i: Schizophrenia Research. - : Elsevier BV. - 0920-9964 .- 1573-2509. ; 218, s. 226-232
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Tidskriftsartikel (refereegranskat)abstract
- Patients with schizophrenia exhibit a higher cardiovascular mortality compared to the general population which has been attributed to life-style factors, genetic susceptibility and antipsychotic medication. Recent echocardiographic studies have pointed to an association between clozapine treatment and reduced left ventricular ejection fraction (LVEF), a measure that has been inversely associated with adverse outcomes including all-cause mortality. Cardiovascular magnetic resonance (CMR) is considered the reference method for LVEF measurement. The aim of the present study was to investigate the LVEF in patients with schizophrenia on long-term treatment with antipsychotics and healthy controls. Twenty-nine adult patients with schizophrenia on long-term medication with antipsychotics and 27 age-, sex- and body mass index-matched healthy controls (mean ages 44 and 45 years, respectively) were recruited from outpatient psychiatric clinics in Uppsala, Sweden. The participants were interviewed and underwent physical examination, biochemical analyses, electrocardiogram and CMR. Men with schizophrenia on long-term antipsychotic treatment showed significantly lower LVEF than controls (p = 0.0076), whereas no such difference was evident among women (p = 0.44). Specifically, clozapine-treated male patients had 10.6% lower LVEF than male controls (p = 0.0064), whereas the LVEF was 5.5% below that of controls among male patients treated with non-clozapine antipsychotics (p = 0.047). Among medicated men with schizophrenia, we found significantly lower LVEF compared to healthy individuals, suggesting the need of routine cardiac monitoring in this patient group. This is the first study showing a significant negative association between treatment with non-clozapine antipsychotics and LVEF.
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| 16. |
- Asif, Sana, M.D, PhD student, et al.
(författare)
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Validation of an MPC polymer coating to attenuate surface- induced cross-talk between the complement and coagulation systems in whole blood in in vitro and in vivo models
- 2019
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Ingår i: Macromolecular Bioscience. - : Wiley-VCH Verlagsgesellschaft. - 1616-5187 .- 1616-5195. ; 19:5
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Tidskriftsartikel (refereegranskat)abstract
- Artificial surfaces that come into contact with blood induce an immediate activation of the cascade systems of the blood, leading to a thrombotic and/or inflammatory response that can eventually cause damage to the biomaterial or the patient, or to both. Heparin coating has been used to improve hemocompatibility, and another approach is 2-methacryloyloxyethyl phosphorylcholine (MPC)-based polymer coatings. Here, the aim is to evaluate the hemocompatibility of MPC polymer coating by studying the interactions with coagulation and complement systems using human blood in vitro model and pig in vivo model. The stability of the coatings is investigated in vitro and MPC polymer-coated catheters are tested in vivo by insertion into the external jugular vein of pigs to monitor the catheters' antithrombotic properties. There is no significant activation of platelets or of the coagulation and complement systems in the MPC polymer-coated one, which was superior in hemocompatibility to non-coated matrix surfaces. The protective effect of the MPC polymer coat does not decline after incubation in human plasma for up to 2 weeks. With MPC polymer-coated catheters, it is possible to easily draw blood from pig for 4 days in contrast to the case for non-coated catheters, in which substantial clotting is seen.
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| 17. |
- Asif, Sana, M.D, PhD student, et al.
(författare)
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Validation of an MPC polymer coating to reduce surface-induced cascade system activation in whole blood in in vitroand in vivo models
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- ABSTRACTBackground: Artificial surfaces that come into contact with blood (e.g., when used in various forms of biomedical device) induce an immediate activation of the cascade systems of the blood, the coagulation and complement systems. These reactions may lead to a thrombotic and/or inflammatory response that can eventually cause damage to the biomaterial or the patient, or to both. Multiple strategies to dampen these reactions have been employed, with heparin conjugation to the material surface being the most successfulthus far. Another approach to improving hemocompatibility is to use 2-methacryloyloxyethyl phosphorylcholine (MPC)-based polymer coatings.Experimental: In the present study, we evaluated the effectiveness of MPC polymer coating and compared it to a commercially available heparin coating in various in vitromodels using fresh human blood with the aim to replace the costly heparin-coated equipment with the more economic MPC. We then investigated the stability of the various coatings in human plasma in vitrofor 2 weeks. Finally, we inserted MPC polymer-coated catheters into the external jugular vein of pigs and monitored the catheters’ antithrombotic properties for 4 days.Results: 1) There was no significant activation of platelets and of the coagulation and complement systems on the MPC polymer-coated or the commercially available heparin surface. 2) Both coats were superior in hemocompatibility to non-coated matrix surfaces. 3) The protective effect of the MPC polymer coat did not decline after incubation in plasma for up to 2 weeks. 4) With MPC polymer-coated catheters, it was possible to easily draw blood from experimental animals for 4 days, in contrast to the case for heparin-flushed commercially available non-coated catheters, in which substantial clotting was seen.
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| 18. |
- Baghdassarian, Eva, et al.
(författare)
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Auditory brainstem response (ABR) profiling tests as diagnostic support for schizophrenia and adult attention-deficit hyperactivity disorder (ADHD)
- 2018
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Ingår i: Acta Neuropsychiatrica. - : Cambridge University Press (CUP). - 0924-2708 .- 1601-5215. ; 30:3, s. 137-147
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To evaluate the performances of two auditory brainstem response (ABR) profiling tests as potential biomarkers and diagnostic support for schizophrenia and adult attention-deficit hyperactivity disorder (ADHD), respectively, in an investigator-initiated blinded study design.Method: Male and female patients with schizophrenia (n=26) and adult ADHD (n=24) meeting Diagnostic and Statistical Manual of Mental Disorders Fourth Edition (DSM IV) diagnostic criteria and healthy controls (n=58) comprised the analysis set (n=108) of the total number of study participants (n=119). Coded sets of randomized ABR recordings were analysed by an independent party blinded to clinical diagnoses before a joint code-breaking session.Results: The ABR profiling test for schizophrenia identified schizophrenia patients versus controls with a sensitivity of 84.6% and a specificity of 93.1%. The ADHD test identified patients with adult ADHD versus controls with a sensitivity of 87.5% and a specificity of 91.4%.Conclusion: The ABR profiling tests discriminated schizophrenia and ADHD versus healthy controls with high sensitivity and specificity. The methods deserve to be further explored in larger clinical studies including a broad range of psychiatric disorders to determine their utility as potential diagnostic biomarkers.
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| 19. |
- Bengtsson, Göran, et al.
(författare)
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Öbiogeografisk teori och bildning av naturreservat
- 1982
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Naturreservat kan betraktas som ekologiska öar i en alltmer påverkad omgivning och därmed bedömas utifrån öbiogeografisk teori. Innebörden av denna teori, som beskriver sambandet mellan ö-storlek och artantal med utgångspunkt från invandrings- resp. utdöendehastigheter presenteras, liksom den debatt som uppstått kring teorin. Analyser demonstrerar ö-teorins giltighet för o lika organismgrupper (fiskar, skalbaggar, kärlväxter) i Sverige. De teoretiska konsekvenserna av förändringar av reservat ytor för antalet fågelarter diskuteras, samt den konflikt som råder mellan intressen företrädande dagens produktionslandskap och ur ö-teoretisk synvinkel önskvärd bildning av reservat. Det aktuella antalet svenska reservat och deras yta, storleksfördelning, former och lokalisering är i ringa samstämmighet med ö-teorin. För att i framtiden ha kvar ett så varierat växt- och djurliv som möjligt måste den totala reservatsytan öka. Man bör avsätta fler större reservat än små, och minska avstånden till andra reservat genom att skapa nya småreservat eller biotopkorridorer. Reservat bör ha så liten omkrets i förhållande till yta som möjligt och vidare, ej nödvändigtvis vara anpassade till aktuella ägogränser.
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| 20. |
- Bengtsson, Kenneth, et al.
(författare)
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Så kan Sverige bli ledande nation i resurseffektivitet
- 2016
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Ingår i: Dagens Nyheter. - 1101-2447. ; :2016-04-30
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- Ny rapport. Det svenska näringslivet kan bli mer hållbart, resurssmart och därmed internationellt konkurrenskraftigt. Men för det behövs en tydlig politisk avsiktsförklaring och riktlinjer. Vi har listat sex områden där policyutveckling brådskar, skriver företrädare för näringsliv, forskning och myndigheter i en gemensam uppmaning.
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| 21. |
- Berg, Björn, et al.
(författare)
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Manganese dynamics in decomposing needle and leaf litter : a synthesis
- 2013
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Ingår i: Canadian Journal of Forest Research. - : Canadian Science Publishing. - 0045-5067 .- 1208-6037. ; 43:12, s. 1127-1136
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the present synthesis paper was to determine whether concentration changes and net release of manganese (Mn), as related to accumulated litter mass loss, are related to initial Mn concentration, mean annual temperature (MAT), mean annual precipitation (MAP), and tree genus or species. We also examined whether limit values for decomposition are related to initial litter Mn concentration, MAT, and MAP. We compiled 84 foliar litter decomposition studies, conducted mainly in boreal and temperate forest ecosystems, for which Mn dynamics had been well documented. Manganese concentration and amount were related to accumulated litter mass loss at each sampling time for each single study, as well as for (i) all studies combined (n = 748) and (ii) for species groups viz. Norway spruce (Picea abies (L.) Karst.) (n = 284), pine (Pinus) species (n = 330), and deciduous species (n = 214). The changes in Mn concentration with accumulated mass loss followed quadratic functions showing significantly higher Mn concentrations for Norway spruce vs. Scots pine (Pinus sylvestris L.) (p < 0.0001) and vs. deciduous species (p < 0.01), as well as significantly higher for deciduous species vs. Scots pine (p < 0.0001). Manganese release rates were different among the three species groups (p < 0.001). Still, rates were related to initial Mn concentrations (p < 0.001) for all litter types combined and for the three species groups. Norway spruce released Mn more slowly than pine and deciduous species. Rates were related to climatic factors for litter of Norway spruce and deciduous species. Limit values for all litter and for pine species separately were related to Mn (p < 0.001) and MAT (p < 0.001). For Norway spruce, limit values were related to MAT (p < 0.001) and MAP (p < 0.01). It appears that Norway spruce litter retains Mn more strongly in the litter structure, producing humus richer in Mn than does litter of pine and deciduous species.
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| 22. |
- Berg, Björn, et al.
(författare)
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Manganese in the litter fall-forest floor continuum of boreal and temperate pine and spruce forest ecosystems : a review
- 2015
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Ingår i: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 358, s. 248-260
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Forskningsöversikt (refereegranskat)abstract
- We have reviewed the literature on the role of manganese (Mn) in the litter fall-to-humus subsystem. Available data gives a focus on North European coniferous forests. Manganese concentrations in pine (Pinus spp.) foliar litter are highly variable both spatially and temporally within the same litter species and for the genus Pinus we found a range from 0.03 to 3.7mgg-1. Concentrations were related negatively to site mean annual temperature (MAT) and annual actual evapotranspiration (AET) for pine species litter but not for that of Norway spruce (Picea abies) as a single species. Combined data for several species showed a highly significant relationship to MAT.Manganese peroxidase is an Mn-dependent enzyme, found in white-rot fungi, essential for the degradation of lignin and ligninlike compounds. The decomposition rates of lignified litter tissue (late phase) is positively related to the litter’s Mn concentration. Further, the Mn concentration is positively related to the limit value for decomposition - the higher the Mn concentration the smaller the stable litter fraction. Manganese release from decomposing litter appears at least in part to be species related. Thus was release from pine needle litter significantly faster (p<. 0.001) than that from the Mn-richer litter of Norway spruce. Over Northern Europe concentrations of total Mn in mor humus as well as extractable Mn in the mineral soil increase with decreasing MAT and over a climatic gradient the Mn concentrations in Norway spruce mor increase more with decreasing MAT than in a gradient with Scots pine. Higher Mn concentrations in humus appear to decrease its stability and result in a higher release of carbon dioxide (CO2) and dissolved organic carbon (DOC). We conclude that this may explain (i) the lower amount of carbon (C) in mor layers under Norway spruce as compared to Scots pine as well as the higher amount of C in mineral soil under spruce. The increase in nitrogen (N) concentration in humus, following N fertilization resulted in a decrease in that of Mn. We have found four cases - empirical - with negative interaction between Mn and N; (i) in pine foliar litter fall concentrations of Mn decrease with site MAT whereas those of N increase, (ii) in decomposing late-stage litter with N retarding and Mn stimulating decomposition, (iii) for the stable phase, limit values are related negatively to N and positively to Mn, and (iv) Mn concentrations in humus decrease with MAT whereas those of N increase.
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| 23. |
- Berglund, Björn, et al.
(författare)
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Characterization of extended-spectrum -lactamase-producing Escherichia coli harboring mcr-1 and toxin genes from human fecal samples from China
- 2018
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Ingår i: Future Microbiology. - : FUTURE MEDICINE LTD. - 1746-0913 .- 1746-0921. ; 13:15, s. 1647-1656
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Tidskriftsartikel (refereegranskat)abstract
- Aim: To characterize extended-spectrum -lactamase-producing Escherichia coli harboring the colistin resistance gene mcr-1 from human fecal samples collected in 2012 in a rural area of Shandong province, PR China. Materials amp; methods: Whole-genome sequencing and antimicrobial susceptibility testing was performed on 25 mcr-1-positive isolates to determine carriage of antibiotic resistance and virulence genes, diversity and antibiotic resistance profiles. Results: The isolates were highly genetically diverse and carried a large variety of different antibiotic resistance genes. The multidrug-resistance rate was high (96%). Virulence genes associated with intestinal pathogenic E. coli were carried by 32% of the isolates. Conclusion: Further monitoring of the epidemiological situation is necessary to ensure a preparedness for potential emergence of novel, difficult-to-treat strains and awareness of available treatment options.
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| 24. |
- Berglund, Björn, et al.
(författare)
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Clonal spread of carbapenem-resistant Klebsiella pneumoniae among patients at admission and discharge at a Vietnamese neonatal intensive care unit
- 2021
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Ingår i: Antimicrobial Resistance and Infection Control. - : BMC. - 2047-2994. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- Background The increasing prevalence of carbapenem-resistant Enterobacteriaceae (CRE) is a growing problem globally, particularly in low- to middle-income countries (LMICs). Previous studies have shown high rates of CRE colonisation among patients at hospitals in LMICs, with increased risk of hospital-acquired infections. Methods We isolated carbapenem-resistant Klebsiella pneumoniae (CRKP) from faecal samples collected in 2017 from patients at admission and discharge at a Vietnamese neonatal intensive care unit (NICU). 126 CRKP were whole-genome sequenced. The phylogenetic relationship between the isolates and between clinical CRKP isolates collected in 2012-2018 at the same hospital were investigated. Results NDM-type carbapenemase-(61%) and KPC-2-encoding genes (41%) were the most common carbapenem resistance genes observed among the admission and discharge isolates. Most isolates (56%) belonged to three distinct clonal clusters of ST15, carrying bla(KPC-2), bla(NDM-1) and bla(NDM-4), respectively. Each cluster also comprised clinical isolates from blood collected at the study hospital. The most dominant ST15 clone was shown to be related to isolates collected from the same hospital as far back as in 2012. Conclusions Highly resistant CRKP were found colonising admission and discharge patients at a Vietnamese NICU, emphasising the importance of continued monitoring. Whole-genome sequencing revealed a population of CRKP consisting mostly of ST15 isolates in three clonally related clusters, each related to blood isolates collected from the same hospital. Furthermore, clinical isolates collected from previous years (dating back to 2012) were shown to likely be clonally descended from ST15 isolates in the largest cluster, suggesting a successful hospital strain which can colonise inpatients.
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| 25. |
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