| 1. |
- Erni, W., et al.
(författare)
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Technical design report for the PANDA (AntiProton Annihilations at Darmstadt) Straw Tube Tracker
- 2013
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Ingår i: European Physical Journal A. Hadrons and Nuclei. - : Springer Science and Business Media LLC. - 1434-6001 .- 1434-601X. ; 49:2
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Tidskriftsartikel (refereegranskat)abstract
- This document describes the technical layout and the expected performance of the Straw Tube Tracker (STT), the main tracking detector of the PANDA target spectrometer. The STT encloses a Micro-Vertex-Detector (MVD) for the inner tracking and is followed in beam direction by a set of GEM stations. The tasks of the STT are the measurement of the particle momentum from the reconstructed trajectory and the measurement of the specific energy loss for a particle identification. Dedicated simulations with full analysis studies of certain proton-antiproton reactions, identified as being benchmark tests for the whole PANDA scientific program, have been performed to test the STT layout and performance. The results are presented, and the time lines to construct the STT are described.
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| 2. |
- Webber, K. B., et al.
(författare)
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Chemical Analysis of the Brightest Star of the Cetus II Ultrafaint Dwarf Galaxy Candidate
- 2023
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Ingår i: Astrophysical Journal. - 0004-637X .- 1538-4357. ; 959:2
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Tidskriftsartikel (refereegranskat)abstract
- We present a detailed chemical abundance analysis of the brightest star in the ultrafaint dwarf (UFD) galaxy candidate Cetus II from high-resolution Magellan/MIKE spectra. For this star, DES J011740.53-173053, abundances or upper limits of 18 elements from carbon to europium are derived. Its chemical abundances generally follow those of other UFD galaxy stars, with a slight enhancement of the alpha-elements (Mg, Si, and Ca) and low neutron-capture element (Sr, Ba, and Eu) abundances supporting the classification of Cetus II as a likely UFD. The star exhibits lower Sc, Ti, and V abundances than Milky Way (MW) halo stars with similar metallicity. This signature is consistent with yields from a supernova originating from a star with a mass of similar to 11.2 M-circle dot. In addition, the star has a potassium abundance of [K/Fe] = 0.81, which is somewhat higher than the K abundances of MW halo stars with similar metallicity, a signature that is also present in a number of UFD galaxies. A comparison including globular clusters and stellar stream stars suggests that high K is a specific characteristic of some UFD galaxy stars and can thus be used to help classify objects as UFD galaxies.
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| 3. |
- Cooper, Alan, et al.
(författare)
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A global environmental crisis 42,000 years ago
- 2021
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 371:6531, s. 811-818
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Tidskriftsartikel (refereegranskat)abstract
- Geological archives record multiple reversals of Earth’s magnetic poles, but the global impacts of these events, if any, remain unclear. Uncertain radiocarbon calibration has limited investigation of the potential effects of the last major magnetic inversion, known as the Laschamps Excursion [41 to 42 thousand years ago (ka)]. We use ancient New Zealand kauri trees (Agathis australis) to develop a detailed record of atmospheric radiocarbon levels across the Laschamps Excursion. We precisely characterize the geomagnetic reversal and perform global chemistry-climate modeling and detailed radiocarbon dating of paleoenvironmental records to investigate impacts. We find that geomagnetic field minima ~42 ka, in combination with Grand Solar Minima, caused substantial changes in atmospheric ozone concentration and circulation, driving synchronous global climate shifts that caused major environmental changes, extinction events, and transformations in the archaeological record.
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| 4. |
- Cooper, Alan, et al.
(författare)
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Response to comment on “A global environmental crisis 42,000 years ago”
- 2021
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 374:6570
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Tidskriftsartikel (refereegranskat)abstract
- Our paper about the impacts of the Laschamps Geomagnetic Excursion 42,000 years ago has provoked considerable scientific and public interest, particularly in the so-called Adams Event associated with the initial transition of the magnetic poles. Although we welcome the opportunity to discuss our new ideas, Hawks’ assertions of misrepresentation are especially disappointing given his limited examination of the material.
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| 5. |
- Trydeman Knudsen, Marie, et al.
(författare)
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Characterization factors for land use impacts on biodiversity in life cycle assessment based on direct measures of plant species richness in European farmland in the ‘Temperate Broadleaf and Mixed Forest`.
- 2017
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 580, s. 358-366
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Tidskriftsartikel (refereegranskat)abstract
- Life Cycle Assessment (LCA) is a widely used tool to assess environmental sustainability of products. The LCAshould optimally cover themost important environmental impact categories such as climate change, eutrophicationand biodiversity. However, impacts on biodiversity are seldom included in LCAs due tomethodological limitationsand lack of appropriate characterization factors. When assessing organic agricultural products theomission of biodiversity in LCA is problematic, because organic systems are characterized by higher species richnessat field level compared to the conventional systems. Thus, there is a need for characterization factors to estimateland use impacts on biodiversity in life cycle assessment that are able to distinguish between organic andconventional agricultural land use that can be used to supplement and validate the few currently suggested characterization factors. Based on a unique dataset derived fromfield recording of plant species diversity in farmlandacross six European countries, the present study provides newmidpoint occupation Characterization Factors(CF) expressing the Potentially Disappeared Fraction (PDF) to estimate land use impacts on biodiversity in the‘Temperate Broadleaf and Mixed Forest’ biome in Europe. The method is based on calculation of plant specieson randomly selected test sites in the biome and enables the calculation of characterization factors that are sensitiveto particular types ofmanagement.While species richness differs between countries, the calculated CFs areable to distinguish between different land use types (pastures (monocotyledons or mixed), arable land andhedges) and management practices (organic or conventional production systems) across countries. The new occupationCFs can be used to supplement or validate the fewcurrent CF's and can be applied in LCAs of agriculturalproducts to assess land use impacts on species richness in the ‘Temperate Broadleaf and Mixed Forest’ biome.
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| 6. |
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| 7. |
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| 8. |
- Spanswick, E., et al.
(författare)
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Global observations of substorm injection region evolution : 27 August 2001
- 2009
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Ingår i: Annales Geophysicae. - 0992-7689 .- 1432-0576. ; 27:5, s. 2019-2025
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Tidskriftsartikel (refereegranskat)abstract
- We present riometer and in situ observations of a substorm electron injection on 27 August 2001. The event is seen at more than 20 separate locations (including ground stations and 6 satellites: Cluster, Polar, Chandra, and 3 Los Alamos National Laboratory (LANL) spacecraft). The injection is observed to be dispersionless at 12 of these locations. Combining these observations with information from the GOES-8 geosynchronous satellite we argue that the injection initiated near geosynchronous orbit and expanded pole-ward (tailward) and equatorward (earthward) afterward. Further, the injection began several minutes after the reconnection identified in the Cluster data, thus providing concrete evidence that, in at least some events, near-Earth reconnection has little if any ionospheric signature.
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| 9. |
- Begnini, Fabio, et al.
(författare)
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Importance of Binding Site Hydration and Flexibility Revealed When Optimizing a Macrocyclic Inhibitor of the Keap1-Nrf2 Protein-Protein Interaction
- 2022
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Ingår i: Journal of Medicinal Chemistry. - : American Chemical Society (ACS). - 0022-2623 .- 1520-4804. ; 65:4, s. 3473-3517
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Tidskriftsartikel (refereegranskat)abstract
- Upregulation of the transcription factor Nrf2 by inhibition of the interaction with its negative regulator Keap1 constitutes an opportunity for the treatment of disease caused by oxidative stress. We report a structurally unique series of nanomolar Keap1 inhibitors obtained from a natural product-derived macrocyclic lead. Initial exploration of the structure-derived macrocyclic lead. Initial exploration of the structure-activity relationship of the lead, followed by structure-guided optimization, resulted in a 100-fold improvement in inhibitory potency. The macrocyclic core of the nanomolar inhibitors positions three pharmacophore units for productive interactions with key residues of Keap1, including R415, R483, and Y572. Ligand optimization resulted in the displacement of a coordinated water molecule from the Keap1 binding site and a significantly altered thermodynamic profile. In addition, minor reorganizations of R415 and R483 were accompanied by major differences in affinity between ligands. This study therefore indicates the importance of accounting both for the hydration and flexibility of the Keap1 binding site when designing high-affinity ligands.
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| 10. |
- El Masri, R., et al.
(författare)
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Extracellular endosulfatase Sulf-2 harbors a chondroitin/dermatan sulfate chain that modulates its enzyme activity
- 2022
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Ingår i: Cell Reports. - : Elsevier BV. - 2211-1247. ; 38:11
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Tidskriftsartikel (refereegranskat)abstract
- Sulfs represent a class of unconventional sulfatases which provide an original post-synthetic regulatory mechanism for heparan sulfate polysaccharides and are involved in multiple physiopathological processes, including cancer. However, Sulfs remain poorly characterized enzymes, with major discrepancies regarding their in vivo functions. Here we show that human SuIf-2 (HSulf-2) harbors a chondroitin/dermatan sulfate glycosaminoglycan (GAG) chain, attached to the enzyme substrate-binding domain. We demonstrate that this GAG chain affects enzyme/substrate recognition and tunes HSulf-2 activity in vitro and in vivo. In addition, we show that mammalian hyaluronidase acts as a promoter of HSulf-2 activity by digesting its GAG chain. In conclusion, our results highlight HSulf-2 as a proteoglycan-related enzyme and its GAG chain as a critical non-catalytic modulator of the enzyme activity. These findings contribute to clarifying the conflicting data on the activities of the Sulfs.
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