| 1. |
- Algaba, Juan-Carlos, et al.
(författare)
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Broadband Multi-wavelength Properties of M87 during the 2017 Event Horizon Telescope Campaign
- 2021
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Ingår i: Astrophysical Journal Letters. - : American Astronomical Society. - 2041-8213 .- 2041-8205. ; 911:1
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Forskningsöversikt (refereegranskat)abstract
- In 2017, the Event Horizon Telescope (EHT) Collaboration succeeded in capturing the first direct image of the center of the M87 galaxy. The asymmetric ring morphology and size are consistent with theoretical expectations for a weakly accreting supermassive black hole of mass ∼6.5 × 109 M o˙. The EHTC also partnered with several international facilities in space and on the ground, to arrange an extensive, quasi-simultaneous multi-wavelength campaign. This Letter presents the results and analysis of this campaign, as well as the multi-wavelength data as a legacy data repository. We captured M87 in a historically low state, and the core flux dominates over HST-1 at high energies, making it possible to combine core flux constraints with the more spatially precise very long baseline interferometry data. We present the most complete simultaneous multi-wavelength spectrum of the active nucleus to date, and discuss the complexity and caveats of combining data from different spatial scales into one broadband spectrum. We apply two heuristic, isotropic leptonic single-zone models to provide insight into the basic source properties, but conclude that a structured jet is necessary to explain M87's spectrum. We can exclude that the simultaneous γ-ray emission is produced via inverse Compton emission in the same region producing the EHT mm-band emission, and further conclude that the γ-rays can only be produced in the inner jets (inward of HST-1) if there are strongly particle-dominated regions. Direct synchrotron emission from accelerated protons and secondaries cannot yet be excluded.
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| 2. |
- Abgrall, N., et al.
(författare)
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The large enriched germanium experiment for neutrinoless double beta decay (LEGEND)
- 2017
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Ingår i: AIP Conference Proceedings. - : Author(s). - 1551-7616 .- 0094-243X. ; 1894
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Konferensbidrag (refereegranskat)abstract
- The observation of neutrinoless double-beta decay (0νββ) would show that lepton number is violated, reveal that neu-trinos are Majorana particles, and provide information on neutrino mass. A discovery-capable experiment covering the inverted ordering region, with effective Majorana neutrino masses of 15 - 50 meV, will require a tonne-scale experiment with excellent energy resolution and extremely low backgrounds, at the level of ∼0.1 count /(FWHM·t·yr) in the region of the signal. The current generation 76Ge experiments GERDA and the Majorana Demonstrator, utilizing high purity Germanium detectors with an intrinsic energy resolution of 0.12%, have achieved the lowest backgrounds by over an order of magnitude in the 0νββ signal region of all 0νββ experiments. Building on this success, the LEGEND collaboration has been formed to pursue a tonne-scale 76Ge experiment. The collaboration aims to develop a phased 0νββ experimental program with discovery potential at a half-life approaching or at 1028 years, using existing resources as appropriate to expedite physics results.
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| 3. |
- Andersen, M. R., et al.
(författare)
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Comparative genomics of citric-acid-producing Aspergillus niger ATCC 1015 versus enzyme-producing CBS 513.88
- 2011
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Ingår i: Genome Research. - : Cold Spring Harbor Laboratory. - 1088-9051 .- 1549-5469. ; 21:6, s. 885-897
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Tidskriftsartikel (refereegranskat)abstract
- The filamentous fungus Aspergillus niger exhibits great diversity in its phenotype. It is found globally, both as marine and terrestrial strains, produces both organic acids and hydrolytic enzymes in high amounts, and some isolates exhibit pathogenicity. Although the genome of an industrial enzyme-producing A. niger strain (CBS 513.88) has already been sequenced, the versatility and diversity of this species compel additional exploration. We therefore undertook wholegenome sequencing of the acidogenic A. niger wild-type strain (ATCC 1015) and produced a genome sequence of very high quality. Only 15 gaps are present in the sequence, and half the telomeric regions have been elucidated. Moreover, sequence information from ATCC 1015 was used to improve the genome sequence of CBS 513.88. Chromosome-level comparisons uncovered several genome rearrangements, deletions, a clear case of strain-specific horizontal gene transfer, and identification of 0.8 Mb of novel sequence. Single nucleotide polymorphisms per kilobase (SNPs/kb) between the two strains were found to be exceptionally high (average: 7.8, maximum: 160 SNPs/kb). High variation within the species was confirmed with exo-metabolite profiling and phylogenetics. Detailed lists of alleles were generated, and genotypic differences were observed to accumulate in metabolic pathways essential to acid production and protein synthesis. A transcriptome analysis supported up-regulation of genes associated with biosynthesis of amino acids that are abundant in glucoamylase A, tRNA-synthases, and protein transporters in the protein producing CBS 513.88 strain. Our results and data sets from this integrative systems biology analysis resulted in a snapshot of fungal evolution and will support further optimization of cell factories based on filamentous fungi
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| 4. |
- Wortman, J. R., et al.
(författare)
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The 2008 update of the Aspergillus nidulans genome annotation: A community effort
- 2009
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Ingår i: Fungal Genetics and Biology. - : Elsevier BV. - 1096-0937 .- 1087-1845. ; 46, s. S2-S13
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Tidskriftsartikel (refereegranskat)abstract
- The identification and annotation of protein-coding genes is one of the primary goals of whole-genome sequencing projects, and the accuracy of predicting the primary protein products of gene expression is vital to the interpretation of the available data and the design of downstream functional applications. Nevertheless, the comprehensive annotation of eukaryotic genomes remains a considerable challenge. Many genomes submitted to public databases, including those of major model organisms, contain significant numbers of wrong and incomplete gene predictions. We present a community-based reannotation of the Aspergillus nidulans genome with the primary goal of increasing the number and quality of protein functional assignments through the careful review of experts in the field of fungal biology. (C) 2009 Elsevier Inc. All rights reserved.
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| 5. |
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| 6. |
- Dicke, B., et al.
(författare)
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Transferring the entatic-state principle to copper photochemistry
- 2018
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Ingår i: Nature Chemistry. - : Springer Science and Business Media LLC. - 1755-4349 .- 1755-4330. ; 10:3, s. 355-362
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Tidskriftsartikel (refereegranskat)abstract
- The entatic state denotes a distorted coordination geometry of a complex from its typical arrangement that generates an improvement to its function. The entatic-state principle has been observed to apply to copper electron-transfer proteins and it results in a lowering of the reorganization energy of the electron-transfer process. It is thus crucial for a multitude of biochemical processes, but its importance to photoactive complexes is unexplored. Here we study a copper complex-with a specifically designed constraining ligand geometry-that exhibits metal-to-ligand charge-transfer state lifetimes that are very short. The guanidine-quinoline ligand used here acts on the bis(chelated) copper(I) centre, allowing only small structural changes after photoexcitation that result in very fast structural dynamics. The data were collected using a multimethod approach that featured time-resolved ultraviolet-visible, infrared and X-ray absorption and optical emission spectroscopy. Through supporting density functional calculations, we deliver a detailed picture of the structural dynamics in the picosecond-to-nanosecond time range.
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| 7. |
- Hofmann, G., et al.
(författare)
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Recombinant bacterial hemoglobin alters metabolism of Aspergillus niger
- 2009
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Ingår i: Metabolic Engineering. - : Elsevier BV. - 1096-7176 .- 1096-7184. ; 11:1, s. 8-12
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Tidskriftsartikel (refereegranskat)abstract
- The filamentous fungus Aspergillus niger is used extensively for the production of enzymes and organic acids. A major problem in industrial fermentations with this fungus is to ensure sufficient supply of oxygen required for respiratory metabolism of the fungus. In case of oxygen limitation, the fungus will produce various by-products like organic acids and polyols. In order to circumvent this problem we here study the effects of the expression of a bacterial hemoglobin protein on the metabolism of A. niger. We integrated the vgb gene from Vitreoscilla sp. into the genome at the pyrA locus behind the strong gpdA promoter from Aspergillus nidulans. Analysis of secreted metabolites, oxygen uptake, CO2 evolution and biomass formation points towards a relief of stress in the mutant expressing VHB when it is exposed to oxygen limitation. Our findings therefore point to an interesting strategy to attenuate unwanted side effects resulting from oxygen limitation during industrial fermentations with A. niger. (C) 2008 Elsevier Inc. All rights reserved.
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| 8. |
- Klein, Andreas, et al.
(författare)
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The Fermi energy as common parameter to describe charge compensation mechanisms: A path to Fermi level engineering of oxide electroceramics
- 2023
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Ingår i: Journal of Electroceramics. - 1573-8663 .- 1385-3449. ; 51
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Tidskriftsartikel (refereegranskat)abstract
- Chemical substitution, which can be iso- or heterovalent, is the primary strategy to tailor material properties. There are various ways how a material can react to substitution. Isovalent substitution changes the density of states while heterovalent substitution, i.e. doping, can induce electronic compensation, ionic compensation, valence changes of cations or anions, or result in the segregation or neutralization of the dopant. While all these can, in principle, occur simultaneously, it is often desirable to select a certain mechanism in order to determine material properties. Being able to predict and control the individual compensation mechanism should therefore be a key target of materials science. This contribution outlines the perspective that this could be achieved by taking the Fermi energy as a common descriptor for the different compensation mechanisms. This generalization becomes possible since the formation enthalpies of the defects involved in the various compensation mechanisms do all depend on the Fermi energy. In order to control material properties, it is then necessary to adjust the formation enthalpies and charge transition levels of the involved defects. Understanding how these depend on material composition will open up a new path for the design of materials by Fermi level engineering.
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| 9. |
- Leiblein, T., et al.
(författare)
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Field study of natural, mechanical and hybrid ventilation systems of 27 office buildings in the temperate zone country switzerland
- 2014
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Ingår i: 13th International Conference on Indoor Air Quality and Climate, Indoor Air 2014; Hong Kong; Hong Kong; 7 July 2014 through 12 July 2014.
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Konferensbidrag (refereegranskat)abstract
- Analyses in this study focus on characteristics of three different clusters of ventilation for office buildings. These comprise natural, mechanical and hybrid ventilation. In a major project study, extensive data was collected from 27 office buildings. Besides physically measurable parameters, psycho-social-oriented surveys of building users and information about building-specific constructional or building technology were compiled. In a selection, results of indoor air quality (IAQ) and indoor environment quality (IEQ) were compared with current standards. Thom's Discomfort Index (DI) suggested that, for all three clusters, populations feeling discomfort are to be expected during the summer months. Responses for certain aspects corresponding to IEQ and IAQ showed a remarkable seasonal divergence of satisfaction with air temperature for naturally ventilated buildings. The appearance of stagnant air is found to occur in its strongest form in naturally and hybrid ventilated buildings. Mechanically ventilated buildings were reported as having the lowest values for satisfaction with air humidity in winter. Each ventilation system comprises characteristic advantages and disadvantages. A tendency might favour, at least seasonally, mechanically or hybrid ventilated buildings. Differences between these two systems are not significant in this sample. The result raises the question of how much technical effort is actually necessary to provide satisfactory ventilation.
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| 10. |
- Monn, C., et al.
(författare)
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Indoor air conditions in offices with different ventilation regimes - results from the QSB project (quality of sustainable buildings)
- 2015
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Ingår i: Gefahrstoffe Reinhaltung der Luft. - 0949-8036. ; 75:5, s. 191-196
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Tidskriftsartikel (refereegranskat)abstract
- During the research project "Quality of Sustainable Buildings" (English: QSB, German: QNB), 27 office buildings in Switzerland were investigated. Objective measurements (air quality CO2, air temperature, relative humidity) were performed and in addition, data on subjective judgements were collected using questionnaires. The analyses of this paper focus on the characteristics of ventilation (natural, mechanical and hybrid ventilation). Mechanically ventilated buildings indicated some advantages during the summer period with respect to the air temperature and in the winter with respect to the air quality (CO2). For naturally ventilated buildings, disadvantages during the winter were observed with respect to the air quality (CO2). The same buildings showed some advantage of a higher relative humidity in the winter period compared with the mechanically ventilated buildings. Subjective judgements did more or less correspond with the measured data. However, some parameters did not. Additional parameters for qualifying indoor air quality (here measured as CO2 concentration) need to be considered. In addition, the study showed a quite good quality (measured and judged) for most of the buildings. In order to contribute to energy savings and to achieve a better level of indoor air quality (e.g. humidity), indoor air temperature could be reduced in winter without negatively affecting the comfort requirements of the office users.
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