| 1. |
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| 2. |
- Han, L., et al.
(författare)
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Cell transcriptomic atlas of the non-human primate Macaca fascicularis
- 2022
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Ingår i: Nature. - : Springer Nature. - 0028-0836 .- 1476-4687. ; 604:7907, s. 723-731
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Tidskriftsartikel (refereegranskat)abstract
- Studying tissue composition and function in non-human primates (NHPs) is crucial to understand the nature of our own species. Here we present a large-scale cell transcriptomic atlas that encompasses over 1 million cells from 45 tissues of the adult NHP Macaca fascicularis. This dataset provides a vast annotated resource to study a species phylogenetically close to humans. To demonstrate the utility of the atlas, we have reconstructed the cell–cell interaction networks that drive Wnt signalling across the body, mapped the distribution of receptors and co-receptors for viruses causing human infectious diseases, and intersected our data with human genetic disease orthologues to establish potential clinical associations. Our M. fascicularis cell atlas constitutes an essential reference for future studies in humans and NHPs.
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| 3. |
- 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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| 4. |
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| 5. |
- Ma, Y. M., et al.
(författare)
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Implementation of trait-based ozone plant sensitivity in the YaleInteractive terrestrial Biosphere model v1.0 to assess global vegetationdamage
- 2023
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Ingår i: Geoscientific Model Development. - 1991-959X. ; 16:8, s. 2261-2276
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Tidskriftsartikel (refereegranskat)abstract
- A major limitation in modeling global ozone (O-3) vegetation damage has long been the reliance on empirical O-3 sensitivity parameters derived from a limited number of species and applied at the level of plant functional types (PFTs), which ignore the large interspecific variations within the same PFT. Here, we present a major advance in large-scale assessments of O-3 plant injury by linking the trait leaf mass per area (LMA) and plant O-3 sensitivity in a broad and global perspective. Application of the new approach and a global LMA map in a dynamic global vegetation model reasonably represents the observed interspecific responses to O-3 with a unified sensitivity parameter for all plant species. Simulations suggest a contemporary global mean reduction of 4.8% in gross primary productivity by O-3, with a range of 1.1 %-12.6% for varied PFTs. Hotspots with damage > 10% are found in agricultural areas in the eastern US, western Europe, eastern China, and India, accompanied by moderate to high levels of surface O-3. Furthermore, we simulate the distribution of plant sensitivity to O-3, which is highly linked with the inherent leaf trait trade-off strategies of plants, revealing high risks for fast-growing species with low LMA, such as crops, grasses, and deciduous trees.
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| 6. |
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| 7. |
- Gu, H., et al.
(författare)
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Ultra-high static magnetic fields cause immunosuppression through disrupting B-cell peripheral differentiation and negatively regulating BCR signaling
- 2023
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Ingår i: Medcomm. ; 4:5
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Tidskriftsartikel (refereegranskat)abstract
- To increase the imaging resolution and detection capability, the field strength of static magnetic fields (SMFs) in magnetic resonance imaging (MRI) has significantly increased in the past few decades. However, research on the side effects of high magnetic field is still very inadequate and the effects of SMF above 1 T (Tesla) on B cells have never been reported. Here, we show that 33.0 T ultra-high SMF exposure causes immunosuppression and disrupts B cell differentiation and signaling. 33.0 T SMF treatment resulted in disturbance of B cell peripheral differentiation and antibody secretion and reduced the expression of IgM on B cell membrane, and these might be intensity dependent. In addition, mice exposed to 33.0 T SMF showed inhibition on early activation of B cells, including B cell spreading, B cell receptor clustering and signalosome recruitment, and depression of both positive and negative molecules in the proximal BCR signaling, as well as impaired actin reorganization. Sequencing and gene enrichment analysis showed that SMF stimulation also affects splenic B cells' transcriptome and metabolic pathways. Therefore, in the clinical application of MRI, we should consider the influence of SMF on the immune system and choose the optimal intensity for treatment. 33.0 T SMF treatment resulted in disturbance of B cell peripheral differentiation and antibody secretion, but lower magnetic fields, including 28.7, 17.8, or the 11.2 T SMFs had much less or no such effects. 33.0 T SMF treatment induced downregulate BCR proximal signaling and impaired F-actin remodeling related BCR clustering. SMF stimulation affected the transcriptome and metabolic pathways of B cells.image.
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| 8. |
- Qi, D., et al.
(författare)
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Rapid Acidification of the Arctic Chukchi Sea Waters Driven by Anthropogenic Forcing and Biological Carbon Recycling
- 2022
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Ingår i: Geophysical Research Letters. - : American Geophysical Union (AGU). - 0094-8276 .- 1944-8007. ; 49:4
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Tidskriftsartikel (refereegranskat)abstract
- The acidification of coastal waters is distinguished from the open ocean because of much stronger synergistic effects between anthropogenic forcing and local biogeochemical processes. However, ocean acidification research is still rather limited in polar coastal oceans. Here, we present a 17-year (2002-2019) observational data set in the Chukchi Sea to determine the long-term changes in pH and aragonite saturation state (omega(arag)). We found that pH and omega(arag) declined in different water masses with average rates of -0.0047 +/- 0.0026 years(-1) and -0.017 +/- 0.009 years(-1), respectively, and are similar to 2-3 times faster than those solely due to increasing atmospheric CO2. We attributed the rapid acidification to the increased dissolved inorganic carbon owing to a combination of ice melt-induced increased atmospheric CO2 invasion and subsurface remineralization induced by a stronger surface biological production as a result of the increased inflow of the nutrient-rich Pacific water.
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| 9. |
- Ching, Tao-Chung, et al.
(författare)
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The JCMT BISTRO-2 Survey: Magnetic Fields of the Massive DR21 Filament
- 2022
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 1538-4357 .- 0004-637X. ; 941:2
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Tidskriftsartikel (refereegranskat)abstract
- We present 850 mu m dust polarization observations of the massive DR21 filament from the B-fields In STar-forming Region Observations (BISTRO) survey, using the POL-2 polarimeter and the SCUBA-2 camera on the James Clerk Maxwell Telescope. We detect ordered magnetic fields perpendicular to the parsec-scale ridge of the DR21 main filament. In the subfilaments, the magnetic fields are mainly parallel to the filamentary structures and smoothly connect to the magnetic fields of the main filament. We compare the POL-2 and Planck dust polarization observations to study the magnetic field structures of the DR21 filament on 0.1-10 pc scales. The magnetic fields revealed in the Planck data are well-aligned with those of the POL-2 data, indicating a smooth variation of magnetic fields from large to small scales. The plane-of-sky magnetic field strengths derived from angular dispersion functions of dust polarization are 0.6-1.0 mG in the DR21 filament and similar to 0.1 mG in the surrounding ambient gas. The mass-to-flux ratios are found to be magnetically supercritical in the filament and slightly subcritical to nearly critical in the ambient gas. The alignment between column density structures and magnetic fields changes from random alignment in the low-density ambient gas probed by Planck to mostly perpendicular in the high-density main filament probed by James Clerk Maxwell Telescope. The magnetic field structures of the DR21 filament are in agreement with MHD simulations of a strongly magnetized medium, suggesting that magnetic fields play an important role in shaping the DR21 main filament and subfilaments.
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| 10. |
- Espeland, Marianne, et al.
(författare)
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Combining target enrichment and Sanger sequencing data to clarify the systematics of the diverse Neotropical butterfly subtribe Euptychiina (Nymphalidae, Satyrinae)
- 2023
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Ingår i: Systematic Entomology. - 0307-6970. ; 48:4, s. 498-570
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Tidskriftsartikel (refereegranskat)abstract
- The diverse, largely Neotropical subtribe Euptychiina is widely regarded as one of the most taxonomically challenging groups among all butterflies. Over the last two decades, morphological and molecular studies have revealed widespread paraphyly and polyphyly among genera, and a comprehensive, robust phylogenetic hypothesis is needed to build a firm generic classification to support ongoing taxonomic revisions at the species level. Here, we generated a dataset that includes sequences for up to nine nuclear genes and the mitochondrial COI ‘barcode’ for a total of 1280 specimens representing 449 described and undescribed species of Euptychiina and 39 out-groups, resulting in the most complete phylogeny for the subtribe to date. In combination with a recently developed genomic backbone tree, this dataset resulted in a topology with strong support for most branches. We recognize eight major clades that each contain two or more genera, together containing all but seven Euptychiina genera. We provide a summary of the taxonomy, diversity and natural history of each clade, and discuss taxonomic changes implied by the phylogenetic results. We describe nine new genera to accommodate 38 described species: Lazulina Willmott, Nakahara & Espeland, gen.n., Saurona Huertas & Willmott, gen.n., Argentaria Huertas & Willmott, gen.n., Taguaiba Freitas, Zacca & Siewert, gen.n., Xenovena Marín & Nakahara, gen.n., Deltaya Willmott, Nakahara & Espeland, gen.n., Modica Zacca, Casagrande & Willmott, gen.n., Occulta Nakahara & Willmott, gen.n., and Trico Nakahara & Espeland, gen.n. We also synonymize Nubila Viloria, Andrade & Henao, 2019 (syn.n.) with Splendeuptychia Forster, 1964, Macrocissia Viloria, Le Crom & Andrade, 2019 (syn.n.) with Satyrotaygetis Forster, 1964, and Rudyphthimoides Viloria, 2022 (syn.n.) with Malaveria Viloria & Benmesbah, 2020. Overall, we revised the generic placement of 79 species (74 new generic combinations and five revised combinations), and as a result all but six described species of Euptychiina are accommodated within 70 named, monophyletic genera. For all newly described genera, we provide illustrations of representative species, drawings of wing venation and male and (where possible) female genitalia, and distribution maps, and summarize the natural history of the genus. For three new monotypic genera, Occulta gen.n., Trico gen.n. and Xenovena gen.n. we provide a taxonomic revision with a review of the taxonomy of each species and data from examined specimens. We provide a revised synonymic list for Euptychiina containing 460 valid described species, 53 subspecies and 255 synonyms, including several new synonyms and reinstated species.
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| 11. |
- Ghorbani, F., et al.
(författare)
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Densely sampled phylogenetic analyses of the Lesser Short-toed Lark (Alaudala rufescens) - Sand Lark (A. raytal) species complex (Aves, Passeriformes) reveal cryptic diversity
- 2020
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Ingår i: Zoologica Scripta. - : Wiley. - 0300-3256 .- 1463-6409.
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Tidskriftsartikel (refereegranskat)abstract
- The taxonomy of the Lesser/Asian Short-toed Lark Alaudala rufescens-cheleensis complex has been debated for decades, mainly because of minor morphological differentiation among the taxa within the complex, and different interpretations of the geographical pattern of morphological characters among different authors. In addition, there have been few studies based on non-morphological traits. It has recently been suggested based on a molecular study of the lark family Alaudidae that the Sand Lark A. raytal is nested within this complex. We here analysed mitochondrial cytochrome b (cyt b) from 130 individuals across the range of this complex (hereafter called Alaudala rufescens-raytal complex), representing all except two of the 18 currently recognized subspecies. We also analysed 11 nuclear markers from a subsample of these individuals, representing all of the clades found in the cyt b tree. Five primary clades were recovered, which confirmed that A. raytal is nested within this complex. Divergence time estimates among these five clades ranged from 1.76 to 3.16 million years (my; 95% highest posterior density [HPD] 1.0-4.51 my) or 1.99-2.53 my (95% HPD 0.96-4.3 my) in different analyses. Only four of the currently recognized subspecies were recovered as monophyletic in the cyt b tree. Our results call for a taxonomic revision, and we tentatively suggest that at least four species should be recognized, although we stress the need for an approach integrating molecular, morphological and other data that are not yet available.
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| 12. |
- Goddi, Ciriaco, et al.
(författare)
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Polarimetric Properties of Event Horizon Telescope Targets from ALMA
- 2021
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Ingår i: Astrophysical Journal Letters. - : American Astronomical Society. - 2041-8213 .- 2041-8205. ; 910:1
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Tidskriftsartikel (refereegranskat)abstract
- We present the results from a full polarization study carried out with the Atacama Large Millimeter/submillimeter Array (ALMA) during the first Very Long Baseline Interferometry (VLBI) campaign, which was conducted in 2017 April in the lambda 3 mm and lambda 1.3 mm bands, in concert with the Global mm-VLBI Array (GMVA) and the Event Horizon Telescope (EHT), respectively. We determine the polarization and Faraday properties of all VLBI targets, including Sgr A*, M87, and a dozen radio-loud active galactic nuclei (AGNs), in the two bands at several epochs in a time window of 10 days. We detect high linear polarization fractions (2%-15%) and large rotation measures (RM > 10(3.3)-10(5.5) rad m(-2)), confirming the trends of previous AGN studies at millimeter wavelengths. We find that blazars are more strongly polarized than other AGNs in the sample, while exhibiting (on average) order-of-magnitude lower RM values, consistent with the AGN viewing angle unification scheme. For Sgr A* we report a mean RM of (-4.2 0.3) x 10(5) rad m(-2) at 1.3 mm, consistent with measurements over the past decade and, for the first time, an RM of (-2.1 0.1) x 10(5) rad m(-2) at 3 mm, suggesting that about half of the Faraday rotation at 1.3 mm may occur between the 3 mm photosphere and the 1.3 mm source. We also report the first unambiguous measurement of RM toward the M87 nucleus at millimeter wavelengths, which undergoes significant changes in magnitude and sign reversals on a one year timescale, spanning the range from -1.2 to 0.3 x 10(5) rad m(-2) at 3 mm and -4.1 to 1.5 x 10(5) rad m(-2) at 1.3 mm. Given this time variability, we argue that, unlike the case of Sgr A*, the RM in M87 does not provide an accurate estimate of the mass accretion rate onto the black hole. We put forward a two-component model, comprised of a variable compact region and a static extended region, that can simultaneously explain the polarimetric properties observed by both the EHT (on horizon scales) and ALMA (which observes the combined emission from both components). These measurements provide critical constraints for the calibration, analysis, and interpretation of simultaneously obtained VLBI data with the EHT and GMVA.
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| 13. |
- Hwang, Jihye, et al.
(författare)
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The JCMT BISTRO Survey: A Spiral Magnetic Field in a Hub-filament Structure, Monoceros R2
- 2022
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 1538-4357 .- 0004-637X. ; 941:1
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Tidskriftsartikel (refereegranskat)abstract
- We present and analyze observations of polarized dust emission at 850 μm toward the central 1 × 1 pc hub-filament structure of Monoceros R2 (Mon R2). The data are obtained with SCUBA-2/POL-2 on the James Clerk Maxwell Telescope (JCMT) as part of the B-fields in Star-forming Region Observations survey. The orientations of the magnetic field follow the spiral structure of Mon R2, which are well described by an axisymmetric magnetic field model. We estimate the turbulent component of the magnetic field using the angle difference between our observations and the best-fit model of the underlying large-scale mean magnetic field. This estimate is used to calculate the magnetic field strength using the Davis–Chandrasekhar–Fermi method, for which we also obtain the distribution of volume density and velocity dispersion using a column density map derived from Herschel data and the C18O (J = 3 - 2) data taken with HARP on the JCMT, respectively. We make maps of magnetic field strengths and mass-to-flux ratios, finding that magnetic field strengths vary from 0.02 to 3.64 mG with a mean value of 1.0 ± 0.06 mG, and the mean critical mass-to-flux ratio is 0.47 ± 0.02. Additionally, the mean Alfvén Mach number is 0.35 ± 0.01. This suggests that, in Mon R2, the magnetic fields provide resistance against large-scale gravitational collapse, and the magnetic pressure exceeds the turbulent pressure. We also investigate the properties of each filament in Mon R2. Most of the filaments are aligned along the magnetic field direction and are magnetically subcritical.
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| 14. |
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| 15. |
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| 16. |
- Li, Y., et al.
(författare)
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Performance Evaluation of Offset Spatial Modulation Systems With Practical Channel Estimation
- 2021
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Ingår i: IEEE Systems Journal. - : Institute of Electrical and Electronics Engineers Inc.. - 1932-8184 .- 1937-9234. ; , s. 1-11
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Tidskriftsartikel (refereegranskat)abstract
- Offset spatial modulation (OSM) is an attractive multiple-input–multiple-output (MIMO) transmission scheme, which alleviates the switching frequency limitation of the radio frequency chain in the spatial modulation technology. In this article, we investigate the bit error performance of OSM in the presence of imperfect channel estimation toward a practical transmission scenario. More specifically, with the aid of union bound technique, a general performance analysis framework of the OSM system with channel estimation errors is proposed. Based on the above analysis framework, the upper bounds of bit error rate for the static and dynamic modes of OSM are both derived, respectively. Finally, simulation results demonstrate that the analytical bounds are tight for a wide range of signal-to-noise ratio (SNR) and variable system configurations.
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| 17. |
- Ng, E. Y. X., et al.
(författare)
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Genome-wide SNPs confirm plumage polymorphism and hybridisation within a Cyornis flycatcher species complex
- 2022
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Ingår i: Zoologica Scripta. - : Wiley. - 0300-3256 .- 1463-6409. ; 52:1, s. 1-16
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Tidskriftsartikel (refereegranskat)abstract
- Morphology has been a leading taxonomic guiding light to systematists for the last couple of hundred years. However, the genetic and - more recently - genomic revolution have produced numerous demonstrations of erroneous classifications that were based on labile morphological traits. We used thousands of genome-wide markers to shed light on evolutionary dynamics in a confusing and taxonomically obscure group of Asian Cyornis flycatchers. Using genomic data, we corroborated recent findings based on three mitochrondrial and five nuclear genes that the two taxa hainanus and klossi which were previously treated as separate species (Cyornis hainanus and Cyornis rubeculoides klossi, respectively) are genomically homogeneous and form a single species, C. hainanus. We also uncovered a novel case of interbreeding between C. hainanus and a non-sister species, C. glaucicomans, illustrating these flycatchers' ability to hybridise in marginal situations even after substantial times of divergence. Our study illustrates how genome-wide loci can shed light on complicated taxonomic problems, resulting in a better integration of phenotypic and genotypic data.
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| 18. |
- Oyama, S., et al.
(författare)
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An Ephemeral Red Arc Appeared at 68 degrees MLat at a Pseudo Breakup During Geomagnetically Quiet Conditions
- 2020
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Ingår i: Journal of Geophysical Research - Space Physics. - : American Geophysical Union (AGU). - 2169-9380 .- 2169-9402. ; 125:10
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Tidskriftsartikel (refereegranskat)abstract
- Various subauroral optical features have been studied by analyzing data collected during periods of geomagnetic disturbances. Most events have been typically found at geomagnetic latitudes of 45-60 degrees. In this study, however, we present a red arc event found at geomagnetic 68 degrees north (L approximate to 7.1) in the Scandinavian sector during a period of geomagnetically quiet conditions within a short intermission between two high-speed solar wind events. The red arc appeared to coincide with a pseudo breakup at geomagnetic 71-72 degrees N and a rapid equatorward expansion of the polar cap. However, the red arc disappeared in approximately 7 min. Simultaneous measurements with the Swarm A/C satellites indicated the appearance of the red arc at the ionospheric trough minimum and a conspicuous enhancement of the electron temperature, suggesting the generation of the arc by heat flux. Since there are meaningful differences in the red arc features from already-known subauroral optical features such as the stable auroral red (SAR) arc, we considered that the red arc is a new phenomenon. We suggest that the ephemeral red arc may represent the moment of SAR arc birth associated with substorm particle injection, which is generally masked by bright dynamic aurorae.
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| 19. |
- Wang,, L., et al.
(författare)
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Domino effect of a natural cascade alpine lake system on the Third Pole
- 2022
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Ingår i: PNAS Nexus. - : Oxford University Press (OUP). - 2752-6542. ; 1:3
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Tidskriftsartikel (refereegranskat)abstract
- Third Pole natural cascade alpine lakes (NCALs) are exceptionally sensitive to climate change, yet the underlying cryosphere-hydrological processes and associated societal impacts are largely unknown. Here, with a state-of-the-art cryosphere-hydrology-lake-dam model, we quantified the notable high-mountain Hoh-Xil NCALs basin (including Lakes Zonag, Kusai, Hedin Noel, and Yanhu, from upstream to downstream) formed by the Lake Zonag outburst in September 2011. We demonstrate that long-term increased precipitation and accelerated ice and snow melting as well as short-term heavy precipitation and earthquake events were responsible for the Lake Zonag outburst; while the permafrost degradation only had a marginal impact on the lake inflows but was crucial to lakeshore stability. The quadrupling of the Lake Yanhu area since 2012 was due to the tripling of inflows (from 0.25 to 0.76 km3/year for 1999 to 2010 and 2012 to 2018, respectively). Prediction of the NCALs changes suggests a high risk of the downstream Qinghai–Tibet Railway, necessitating timely adaptions/mitigations.
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| 20. |
- Wei, C. T., et al.
(författare)
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Cryptic species in a colorful genus: Integrative taxonomy of the bush robins (Aves, Muscicapidae, Tarsiger) suggests two overlooked species
- 2022
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Ingår i: Molecular Phylogenetics and Evolution. - : Elsevier BV. - 1055-7903 .- 1095-9513. ; 175
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Tidskriftsartikel (refereegranskat)abstract
- Several cryptic avian species have been validated by recent integrative taxonomic efforts in the Sino-Himalayan mountains, indicating that avian diversity in this global biodiversity hotspot may be underestimated. In the present study, we investigated species limits in the genus Tarsiger, the bush robins, a group of montane forest specialists with high species richness in the Sino-Himalayan region. Based on comprehensive sampling of all 11 subspecies of the six currently recognized species, we applied an integrative taxonomic approach by combining multilocus, acoustic, plumage and morphometric analyses. Our results reveal that the isolated north-central Chinese populations of Tarsiger cyanurus, described as the subspecies albocoeruleus but usually considered invalid, is distinctive in genetics and vocalisation, but only marginally differentiated in morphology. We also found the Taiwan endemic T. indicus formosanus to be distinctive in genetics, song and morphology from T. i. indicus and T. i. yunnanensis of the Sino-Himalayan mountains. Moreover, Bayesian species delimitation using BPP suggests that both albocoeruleus and formosanus merit full species status. We propose their treatment as 'Qilian Bluetail' T. albocoeruleus and 'Taiwan Bush Robin' T. formosanus, respectively.
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| 21. |
- Zhang, D. Z., et al.
(författare)
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Genomic and phenotypic changes associated with alterations of migratory behaviour in a songbird
- 2022
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Ingår i: Molecular Ecology. - : Wiley. - 0962-1083 .- 1365-294X. ; 32:2, s. 381-92
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Tidskriftsartikel (refereegranskat)abstract
- The seasonal migration of birds is a fascinating natural wonder. Avian migratory behaviour changes are common and are probably a polygenic process as avian migration is governed by multiple correlated components with a variable genetic basis. However, the genetic and phenotypic changes involving migration changes are poorly studied. Using one annotated near-chromosomal level de novo genome assembly, 50 resequenced genomes, hundreds of morphometric data and species distribution information, we investigated population structure and genomic and phenotypic differences associated with differences in migratory behaviour in a songbird species, Yellow-throated Bunting Emberiza elegans (Aves: Emberizidae). Population genomic analyses reveal extensive gene flow between the southern resident and the northern migratory populations of this species. The hand-wing index is significantly lower in the resident populations than in the migratory populations, indicating reduced flight efficiency of the resident populations. Here, we discuss the possibility that nonmigratory populations may have originated from migratory populations though migration loss. We further infer that the alterations of genes related to energy metabolism, nervous system and circadian rhythm may have played major roles in regulating migration change. Our study sheds light on phenotypic and polygenic changes involving migration change.
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| 22. |
- Zhang, H. W., et al.
(författare)
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Cellular automaton modelling of M7C3 carbide growth during solidification of Fe-C-Cr alloy
- 2020
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Ingår i: International conference on modelling of casting, welding and advanced solidification processes (MCWASP XV). - : IOP Publishing.
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Konferensbidrag (refereegranskat)abstract
- A microscopic cellular automaton combined with macroscopic heat and solute transport was developed to simulate the mutual growth and evolution of austenite and M7C3 carbide grains during Fe-C-Cr ternary alloy solidification process. The diffusion of solute C and Cr are contributed together to the constitutional undercooling, together with curvature undercooling, for obtaining the grain growth rate of austenite and M7C3 carbide. Results show that, the absorption of solute C and Cr by M7C3 grain and rejection by austenite grain promote the two grains' cooperative growth. Once they approach to each other, the austenite grain quickly overgrows towards the M7C3 grain till finally envelops it. The simulated solidification morphology of the Fe-4wt%C-17wt%Cr alloy, predicted averaged grain size of M7C3 carbides and C and Cr concentration in austenite grains agree with the experimental measurements and solidification path prediction. The predicted average liquid concentration curve fits with the LR, GS and PE prediction at the initial M7C3 precipitation regime and after austenite grains fully enveloping towards the M7C3 grains, returns to overlap the LR, GS and PE prediction curves.
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| 23. |
- Zhang, Y., et al.
(författare)
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A comprehensive review on self-powered smart bearings
- 2023
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Ingår i: Renewable & sustainable energy reviews. - : Elsevier. - 1364-0321 .- 1879-0690. ; 183
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Forskningsöversikt (refereegranskat)abstract
- Recently, with the development of industrial informatization and intellectualization, the development of smart bearings has attracted a lot of significant attention in an attempt to reduce maintenance costs and increase reliability by providing online health condition monitoring. As a result of advances in miniaturization and low power consumption of wireless sensor nodes (WSNs), self-powered technologies have been considered as a promising method to achieve autonomous WSNs in smart bearings. Although the self-powered technology has received considerable achievements, there are less reviews covering the development of self-powered structures towards smart bearing and providing potential guidelines for the future development. To bridge the gap, this paper presents a comprehensive state-of-the-art review and guidelines on self-powered methods to create smart bearings, including outlining the underlying theory, modeling methods, methodologies and technologies. The topology of a self-powered smart bearing is clarified, and the mechanisms and benefits of piezoelectricity, electromagnetism, triboelectricity, thermoelectricity and wireless power transfer for powering WSNs in smart bearing are discussed. To improve the applicability of self-powered smart bearing in a range of working conditions, the design methodologies and technologies of a variety of transducers are reviewed to provide guidelines for performance enhancement. Finally, the future challenges and perspectives are proposed for outlining potential research directions and opportunities in future self-powered smart bearing systems, including the impact on bearing performance, engineering implementation, reliability, power management and storage.
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| 24. |
- Zhang, Y., et al.
(författare)
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Enhanced variable reluctance energy harvesting for self-powered monitoring
- 2022
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Ingår i: Applied Energy. - : Elsevier BV. - 0306-2619 .- 1872-9118. ; 321
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Tidskriftsartikel (refereegranskat)abstract
- With the rapid development of microelectronic technology, wireless sensor nodes have been widely used in rotational equipment for health condition monitoring. However, for many low-frequency applications, there still remains an open issue of harvesting sufficient electrical energy to provide long-term service. Therefore, in this paper an enhanced variable reluctance energy harvester (EVREH) is proposed for self-powered health monitoring under low-frequency rotation conditions. A periodic arrangement of magnets and teeth is employed to achieve frequency up-conversion for performance enhancement under a specific space constraint. In addition, the permeance of the air gap is calculated by the combined magnetic field division and substituting angle method, and the output model of the EVREH is derived for parametric analysis based on the law of electromagnetic induction. Simulations and experimental evaluations under a range of structural parameters are then carried out to verify the effectiveness of the proposed model and investigate the output performance of the proposed harvester. The experimental results indicate that the proposed energy harvester could produce a voltage of 8.7 V and a power of 726 mW for a rotational speed of 200 rpm, with a power density of 0.545 mW/(cm3∙Hz2). Moreover, a self-powered wireless sensing system based on the proposed energy harvester is demonstrated, obtaining a vibration spectrum of the rotating motor and stator which can determine the health state of the system during low rotational speeds. Therefore, this autonomous self-sensing experiment verifies the potential of the EVREH for self-powered monitoring in low-frequency rotation applications.
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| 25. |
- Zhong, Z. H., et al.
(författare)
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Observations of Dynamical Flux Ropes and Active Multiple X-Line Reconnection at Earth's Magnetopause
- 2023
-
Ingår i: Journal of Geophysical Research - Space Physics. - : American Geophysical Union (AGU). - 2169-9380 .- 2169-9402. ; 128:3
-
Tidskriftsartikel (refereegranskat)abstract
- This paper presents the magnetospheric multiscale (MMS) observations of three flux ropes (FRs) sequentially in a reconnection exhaust at Earth's magnetopause. Three active X-lines, which are responsible for the formation of these FRs, were also detected by MMS, providing strong evidence that the FRs were generated by multiple X-line reconnection. We find that the core field inside the FRs considerably affects the Hall current in the adjacent X-lines. The intense core field of the FRs deflected the electron outflow jet, forming the electron-scale Hall magnetic field on the magnetosheath side. Additionally, an active secondary reconnection was observed at the center of one FR. This secondary reconnection split the FR into two smaller FRs and produced sharp density gradients and intense fluctuations of electric field and current within the FR. These observations advance the understanding of the formation and evolution of FRs during multiple X-line reconnection at magnetopause.
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| 26. |
- Abrahamsen, E. Povl, et al.
(författare)
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ANTARCTICA AND THE SOUTHERN OCEAN
- 2020
-
Ingår i: BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY. - 0003-0007 .- 1520-0477. ; 101:8
-
Tidskriftsartikel (refereegranskat)
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| 27. |
- Akiyama, Kazunori, et al.
(författare)
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First M87 Event Horizon Telescope Results. IX. Detection of Near-horizon Circular Polarization
- 2023
-
Ingår i: Astrophysical Journal Letters. - 2041-8213 .- 2041-8205. ; 957:2
-
Tidskriftsartikel (refereegranskat)abstract
- Event Horizon Telescope (EHT) observations have revealed a bright ring of emission around the supermassive black hole at the center of the M87 galaxy. EHT images in linear polarization have further identified a coherent spiral pattern around the black hole, produced from ordered magnetic fields threading the emitting plasma. Here we present the first analysis of circular polarization using EHT data, acquired in 2017, which can potentially provide additional insights into the magnetic fields and plasma composition near the black hole. Interferometric closure quantities provide convincing evidence for the presence of circularly polarized emission on event-horizon scales. We produce images of the circular polarization using both traditional and newly developed methods. All methods find a moderate level of resolved circular polarization across the image (〈|v|〉 < 3.7%), consistent with the low image-integrated circular polarization fraction measured by the Atacama Large Millimeter/submillimeter Array (|vint| < 1%). Despite this broad agreement, the methods show substantial variation in the morphology of the circularly polarized emission, indicating that our conclusions are strongly dependent on the imaging assumptions because of the limited baseline coverage, uncertain telescope gain calibration, and weakly polarized signal. We include this upper limit in an updated comparison to general relativistic magnetohydrodynamic simulation models. This analysis reinforces the previously reported preference for magnetically arrested accretion flow models. We find that most simulations naturally produce a low level of circular polarization consistent with our upper limit and that Faraday conversion is likely the dominant production mechanism for circular polarization at 230 GHz in M87*
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| 28. |
- Akiyama, Kazunori, et al.
(författare)
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First Sagittarius A∗ Event Horizon Telescope Results. VII. Polarization of the Ring
- 2024
-
Ingår i: Astrophysical Journal Letters. - 2041-8213 .- 2041-8205. ; 964:2
-
Tidskriftsartikel (refereegranskat)abstract
- The Event Horizon Telescope observed the horizon-scale synchrotron emission region around the Galactic center supermassive black hole, Sagittarius A∗ (Sgr A∗), in 2017. These observations revealed a bright, thick ring morphology with a diameter of 51.8 ± 2.3 μas and modest azimuthal brightness asymmetry, consistent with the expected appearance of a black hole with mass M≈ 4 × 106 M⊙. From these observations, we present the first resolved linear and circular polarimetric images of Sgr A∗. The linear polarization images demonstrate that the emission ring is highly polarized, exhibiting a prominent spiral electric vector polarization angle pattern with a peak fractional polarization of ∼40% in the western portion of the ring. The circular polarization images feature a modestly (∼5%°-10%) polarized dipole structure along the emission ring, with negative circular polarization in the western region and positive circular polarization in the eastern region, although our methods exhibit stronger disagreement than for linear polarization. We analyze the data using multiple independent imaging and modeling methods, each of which is validated using a standardized suite of synthetic data sets. While the detailed spatial distribution of the linear polarization along the ring remains uncertain owing to the intrinsic variability of the source, the spiraling polarization structure is robust to methodological choices. The degree and orientation of the linear polarization provide stringent constraints for the black hole and its surrounding magnetic fields, which we discuss in an accompanying publication.
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| 29. |
- Akiyama, Kazunori, et al.
(författare)
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First Sagittarius A∗ Event Horizon Telescope Results. VIII. Physical Interpretation of the Polarized Ring
- 2024
-
Ingår i: Astrophysical Journal Letters. - 2041-8213 .- 2041-8205. ; 964:2
-
Tidskriftsartikel (refereegranskat)abstract
- In a companion paper, we present the first spatially resolved polarized image of Sagittarius A∗ on event horizon scales, captured using the Event Horizon Telescope, a global very long baseline interferometric array operating at a wavelength of 1.3 mm. Here we interpret this image using both simple analytic models and numerical general relativistic magnetohydrodynamic (GRMHD) simulations. The large spatially resolved linear polarization fraction (24%-28%, peaking at ∼40%) is the most stringent constraint on parameter space, disfavoring models that are too Faraday depolarized. Similar to our studies of M87∗, polarimetric constraints reinforce a preference for GRMHD models with dynamically important magnetic fields. Although the spiral morphology of the polarization pattern is known to constrain the spin and inclination angle, the time-variable rotation measure (RM) of Sgr A∗ (equivalent to ≈ 46° ± 12° rotation at 228 GHz) limits its present utility as a constraint. If we attribute the RM to internal Faraday rotation, then the motion of accreting material is inferred to be counterclockwise, contrary to inferences based on historical polarized flares, and no model satisfies all polarimetric and total intensity constraints. On the other hand, if we attribute the mean RM to an external Faraday screen, then the motion of accreting material is inferred to be clockwise, and one model passes all applied total intensity and polarimetric constraints: a model with strong magnetic fields, a spin parameter of 0.94, and an inclination of 150°. We discuss how future 345 GHz and dynamical imaging will mitigate our present uncertainties and provide additional constraints on the black hole and its accretion flow.
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| 30. |
- Akiyama, Kazunori, et al.
(författare)
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The persistent shadow of the supermassive black hole of M 87: I. Observations, calibration, imaging, and analysis*
- 2024
-
Ingår i: Astronomy and Astrophysics. - 0004-6361 .- 1432-0746. ; 681
-
Tidskriftsartikel (refereegranskat)abstract
- In April 2019, the Event Horizon Telescope (EHT) Collaboration reported the first-ever event-horizon-scale images of a black hole, resolving the central compact radio source in the giant elliptical galaxy M 87. These images reveal a ring with a southerly brightness distribution and a diameter of ∼42 μas, consistent with the predicted size and shape of a shadow produced by the gravitationally lensed emission around a supermassive black hole. These results were obtained as part of the April 2017 EHT observation campaign, using a global very long baseline interferometric radio array operating at a wavelength of 1.3 mm. Here, we present results based on the second EHT observing campaign, taking place in April 2018 with an improved array, wider frequency coverage, and increased bandwidth. In particular, the additional baselines provided by the Greenland telescope improved the coverage of the array. Multiyear EHT observations provide independent snapshots of the horizon-scale emission, allowing us to confirm the persistence, size, and shape of the black hole shadow, and constrain the intrinsic structural variability of the accretion flow. We have confirmed the presence of an asymmetric ring structure, brighter in the southwest, with a median diameter of 43.3-3.1+1.5 μas. The diameter of the 2018 ring is remarkably consistent with the diameter obtained from the previous 2017 observations. On the other hand, the position angle of the brightness asymmetry in 2018 is shifted by about 30 relative to 2017. The perennial persistence of the ring and its diameter robustly support the interpretation that the ring is formed by lensed emission surrounding a Kerr black hole with a mass ∼6.5× 109M. The significant change in the ring brightness asymmetry implies a spin axis that is more consistent with the position angle of the large-scale jet.
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| 31. |
- Alström, Per, et al.
(författare)
-
Multiple species within the Striated Prinia Prinia crinigera-Brown Prinia P. polychroa complex revealed through an integrative taxonomic approach
- 2020
-
Ingår i: Ibis. - : Wiley. - 0019-1019 .- 1474-919X. ; 162:3, s. 936-967
-
Tidskriftsartikel (refereegranskat)abstract
- We re-evaluated the taxonomy of the Striated Prinia Prinia crinigera-Brown Prinia P. polychroa complex using molecular, morphological and vocal analyses. The extensive seasonal, sexual, age-related, geographical and taxon-specific variation in this complex has never before been adequately studied. As no previous genetic or vocal analyses have focused on this group, misinterpretation of taxonomic signals from limited conventional morphological study alone was likely. Using mitochondrial and nuclear DNA, we found that P. crinigera sensu lato (s.l.) comprises two non-sister groups of taxa (Himalayan crinigera and Chinese striata groups) that differ substantially morphologically and vocally and that are broadly sympatric in Yunnan Province, China. Prinia polychroa cooki (Myanmar) and P. p. rocki (southern Vietnam) are each morphologically, vocally and genetically distinct. Thai, Cambodian and Laotian populations formerly ascribed to P. p. cooki are morphologically and vocally most similar to and most closely related to Javan P. p. polychroa, and require a new name, proposed here. Prinia p. bangsi of Yunnan is part of the crinigera group rather than of P. polychroa, and hence there is no evidence for sympatry between P. polychroa s.l. and P. crinigera s.l., nor of the occurrence of P. polychroa in mainland China or Taiwan. We recommend the recognition of five species in the complex, with the following suggestions for new English names: Himalayan Prinia P. crinigera sensu stricto (s.s.; with subspecies striatula, crinigera, yunnanensis and bangsi); Chinese Prinia P. striata (subspecies catharia, parumstriata and striata); Burmese Prinia P. cooki (monotypic); Annam Prinia P. rocki (monotypic) and Deignan's Prinia P. polychroa s.s. (subspecies Javan polychroa and the new Southeast Asian taxon). This study underlines the importance of using multiple datasets for the elucidation of diversity of cryptic bird species and their evolutionary history and biogeography.
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| 32. |
- Botvinik-Nezer, Rotem, et al.
(författare)
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Variability in the analysis of a single neuroimaging dataset by many teams
- 2020
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 582, s. 84-88
-
Tidskriftsartikel (refereegranskat)abstract
- Data analysis workflows in many scientific domains have become increasingly complex and flexible. Here we assess the effect of this flexibility on the results of functional magnetic resonance imaging by asking 70 independent teams to analyse the same dataset, testing the same 9 ex-ante hypotheses(1). The flexibility of analytical approaches is exemplified by the fact that no two teams chose identical workflows to analyse the data. This flexibility resulted in sizeable variation in the results of hypothesis tests, even for teams whose statistical maps were highly correlated at intermediate stages of the analysis pipeline. Variation in reported results was related to several aspects of analysis methodology. Notably, a meta-analytical approach that aggregated information across teams yielded a significant consensus in activated regions. Furthermore, prediction markets of researchers in the field revealed an overestimation of the likelihood of significant findings, even by researchers with direct knowledge of the dataset(2-5). Our findings show that analytical flexibility can have substantial effects on scientific conclusions, and identify factors that may be related to variability in the analysis of functional magnetic resonance imaging. The results emphasize the importance of validating and sharing complex analysis workflows, and demonstrate the need for performing and reporting multiple analyses of the same data. Potential approaches that could be used to mitigate issues related to analytical variability are discussed. The results obtained by seventy different teams analysing the same functional magnetic resonance imaging dataset show substantial variation, highlighting the influence of analytical choices and the importance of sharing workflows publicly and performing multiple analyses.
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| 33. |
- Broderick, Avery E., et al.
(författare)
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THEMIS: A Parameter Estimation Framework for the Event Horizon Telescope
- 2020
-
Ingår i: Astrophysical Journal. - : American Astronomical Society. - 1538-4357 .- 0004-637X. ; 897:2
-
Tidskriftsartikel (refereegranskat)abstract
- The Event Horizon Telescope (EHT) provides the unprecedented ability to directly resolve the structure and dynamics of black hole emission regions on scales smaller than their horizons. This has the potential to critically probe the mechanisms by which black holes accrete and launch outflows, and the structure of supermassive black hole spacetimes. However, accessing this information is a formidable analysis challenge for two reasons. First, the EHT natively produces a variety of data types that encode information about the image structure in nontrivial ways; these are subject to a variety of systematic effects associated with very long baseline interferometry and are supplemented by a wide variety of auxiliary data on the primary EHT targets from decades of other observations. Second, models of the emission regions and their interaction with the black hole are complex, highly uncertain, and computationally expensive to construct. As a result, the scientific utilization of EHT observations requires a flexible, extensible, and powerful analysis framework. We present such a framework, Themis, which defines a set of interfaces between models, data, and sampling algorithms that facilitates future development. We describe the design and currently existing components of Themis, how Themis has been validated thus far, and present additional analyses made possible by Themis that illustrate its capabilities. Importantly, we demonstrate that Themis is able to reproduce prior EHT analyses, extend these, and do so in a computationally efficient manner that can efficiently exploit modern high-performance computing facilities. Themis has already been used extensively in the scientific analysis and interpretation of the first EHT observations of M87.
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| 34. |
- Cai, Lei, et al.
(författare)
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DMSP Observations of High-Latitude Dayside Aurora (HiLDA)
- 2021
-
Ingår i: Journal of Geophysical Research - Space Physics. - : AMER GEOPHYSICAL UNION. - 2169-9380 .- 2169-9402. ; 126:4
-
Tidskriftsartikel (refereegranskat)abstract
- We report two events of high-latitude dayside aurora (HiLDA), a large-scale aurora in the dayside polar cap, observed by the Defense Meteorological Satellite Program (DMSP) spacecraft in the northern and southern hemispheres, respectively. While HiLDA in the northern hemisphere was reported before under interplanetary magnetic field (IMF) positive By conditions, we show for the first time a HiLDA event in the southern hemisphere when the IMF negative By component was dominant. Our observations also show that HiLDA is highly dynamical: change in its forms, size, location, and development of fine structures during its long lifetime of hours. The co-occurrence of HiLDA and the duskside oval-aligned transpolar aurora (TPA) may be a common feature during IMF By dominant conditions. Both are associated with the high-latitude reconnection and the cusp. Based on the linear Knight relation, we estimate the distribution of the electron density in the magnetospheric source region of HiLDA. These results indicate that HiLDA maps most probably to the high-latitude lobe tailward of the cusp, where the electron density is down to 0.03-3 cm(-3). The lobe electrons are accelerated by the field-aligned potential drop (up to 10 kV) set up in the poleward part of upward Region 0 field-aligned current (FAC). The total energy flux of HiLDA electrons can be up to 50 mW/m(2), indicating HiLDA precipitation as a potential energy source that impacts the polar ionosphere-thermosphere system.
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| 35. |
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| 36. |
- Eatough, Ralph P., et al.
(författare)
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Verification of Radiative Transfer Schemes for the EHT
- 2020
-
Ingår i: Astrophysical Journal. - : American Astronomical Society. - 1538-4357 .- 0004-637X. ; 897:2
-
Tidskriftsartikel (refereegranskat)abstract
- The Event Horizon Telescope (EHT) Collaboration has recently produced the first resolved images of the central supermassive black hole in the giant elliptical galaxy M87. Here we report on tests of the consistency and accuracy of the general relativistic radiative transfer codes used within the collaboration to model M87∗ and Sgr A∗. We compare and evaluate (1) deflection angles for equatorial null geodesics in a Kerr spacetime; (2) images calculated from a series of simple, parameterized matter distributions in the Kerr metric using simplified emissivities and absorptivities; (3) for a subset of codes, images calculated from general relativistic magnetohydrodynamics simulations using different realistic synchrotron emissivities and absorptivities; (4) observables for the 2017 configuration of EHT, including visibility amplitudes and closure phases. The error in total flux is of order 1% when the codes are run with production numerical parameters. The dominant source of discrepancies for small camera distances is the location and detailed setup of the software "camera"that each code uses to produce synthetic images. We find that when numerical parameters are suitably chosen and the camera is sufficiently far away the images converge and that for given transfer coefficients, numerical uncertainties are unlikely to limit parameter estimation for the current generation of EHT observations. The purpose of this paper is to describe a verification and comparison of EHT radiative transfer codes. It is not to verify EHT models more generally.
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| 37. |
- Fang, Li Tai, et al.
(författare)
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Establishing community reference samples, data and call sets for benchmarking cancer mutation detection using whole-genome sequencing
- 2021
-
Ingår i: Nature Biotechnology. - : Springer Nature. - 1087-0156 .- 1546-1696. ; 39:9, s. 1151-1160
-
Tidskriftsartikel (refereegranskat)abstract
- Tumor-normal paired DNA samples from a breast cancer cell line and a matched lymphoblastoid cell line enable calibration of clinical sequencing pipelines and benchmarking 'tumor-only' or 'matched tumor-normal' analyses. The lack of samples for generating standardized DNA datasets for setting up a sequencing pipeline or benchmarking the performance of different algorithms limits the implementation and uptake of cancer genomics. Here, we describe reference call sets obtained from paired tumor-normal genomic DNA (gDNA) samples derived from a breast cancer cell line-which is highly heterogeneous, with an aneuploid genome, and enriched in somatic alterations-and a matched lymphoblastoid cell line. We partially validated both somatic mutations and germline variants in these call sets via whole-exome sequencing (WES) with different sequencing platforms and targeted sequencing with >2,000-fold coverage, spanning 82% of genomic regions with high confidence. Although the gDNA reference samples are not representative of primary cancer cells from a clinical sample, when setting up a sequencing pipeline, they not only minimize potential biases from technologies, assays and informatics but also provide a unique resource for benchmarking 'tumor-only' or 'matched tumor-normal' analyses.
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| 38. |
- Feng, Hongliang, et al.
(författare)
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Association between accelerometer-measured amplitude of rest-activity rhythm and future health risk : a prospective cohort study of the UK Biobank
- 2023
-
Ingår i: The Lancet Healthy Longevity. - 2666-7568. ; 4:5, s. e200-e210
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The health effects of rest-activity rhythm are of major interest to public health, but its associations with health outcomes remain elusive. We aimed to examine the associations between accelerometer-measured rest-activity rhythm amplitude and health risks among the general UK population.METHODS: We did a prospective cohort analysis of UK Biobank participants aged 43-79 years with valid wrist-worn accelerometer data. Low rest-activity rhythm amplitude was defined as the first quintile of relative amplitude; all other quintiles were classified as high rest-activity rhythm amplitude. Outcomes of interest were defined using International Classification of Diseases 10th Revision codes and consisted of incident cancer and cardiovascular, infectious, respiratory, and digestive diseases, and all-cause and disease-specific (cardiovascular, cancer, and respiratory) mortality. Participants with a current diagnosis of any outcome of interest were excluded. We assessed the associations between decreased rest-activity rhythm amplitude and outcomes using Cox proportional hazards models.FINDINGS: Between June 1, 2013, and Dec 23, 2015, 103 682 participants with available raw accelerometer data were enrolled. 92 614 participants (52 219 [56·4%] women and 40 395 [42·6%] men) with a median age of 64 years (IQR 56-69) were recruited. Median follow-up was 6·4 years (IQR 5·8-6·9). Decreased rest-activity rhythm amplitude was significantly associated with increased incidence of cardiovascular diseases (adjusted hazard ratio 1·11 [95% CI 1·05-1·16]), cancer (1·08 [1·01-1·16]), infectious diseases (1·31 [1·22-1·41]), respiratory diseases (1·26 [1·19-1·34]), and digestive diseases (1·08 [1·03-1·14]), as well as all-cause mortality (1·54 [1·40-1·70]) and disease-specific mortality (1·73 [1·34-2·22] for cardiovascular diseases, 1·32 [1·13-1·55] for cancer, and 1·62 [1·25-2·09] for respiratory diseases). Most of these associations were not modified by age older than 65 years or sex. Among 16 accelerometer-measured rest-activity parameters, low rest-activity rhythm amplitude had the strongest or second- strongest associations with nine health outcomes.INTERPRETATION: Our results suggest that low rest-activity rhythm amplitude might contribute to major health outcomes and provide further evidence to promote risk-modifying strategies associated with rest-activity rhythm to improve health and longevity.
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| 39. |
- Feng, Hongliang, et al.
(författare)
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Associations of timing of physical activity with all-cause and cause-specific mortality in a prospective cohort study
- 2023
-
Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 14:1
-
Tidskriftsartikel (refereegranskat)abstract
- There is a growing interest in the role of timing of daily behaviors in improving health. However, little is known about the optimal timing of physical activity to maximize health benefits. We perform a cohort study of 92,139 UK Biobank participants with valid accelerometer data and all-cause and cause-specific mortality outcomes, comprising over 7 years of median follow-up (638,825 person-years). Moderate-to-vigorous intensity physical activity (MVPA) at any time of day is associated with lower risks for all-cause, cardiovascular disease, and cancer mortality. In addition, compared with morning group (>50% of daily MVPA during 05:00-11:00), midday-afternoon (11:00-17:00) and mixed MVPA timing groups, but not evening group (17:00-24:00), have lower risks of all-cause and cardiovascular disease mortality. These protective associations are more pronounced among the elderly, males, less physically active participants, or those with preexisting cardiovascular diseases. Here, we show that MVPA timing may have the potential to improve public health.
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| 40. |
- Feng, HL, et al.
(författare)
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Associations of timing of physical activity with all-cause and cause-specific mortality in a prospective cohort study
- 2023
-
Ingår i: Nature communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 14:1, s. 930-
-
Tidskriftsartikel (refereegranskat)abstract
- There is a growing interest in the role of timing of daily behaviors in improving health. However, little is known about the optimal timing of physical activity to maximize health benefits. We perform a cohort study of 92,139 UK Biobank participants with valid accelerometer data and all-cause and cause-specific mortality outcomes, comprising over 7 years of median follow-up (638,825 person-years). Moderate-to-vigorous intensity physical activity (MVPA) at any time of day is associated with lower risks for all-cause, cardiovascular disease, and cancer mortality. In addition, compared with morning group (>50% of daily MVPA during 05:00-11:00), midday-afternoon (11:00-17:00) and mixed MVPA timing groups, but not evening group (17:00-24:00), have lower risks of all-cause and cardiovascular disease mortality. These protective associations are more pronounced among the elderly, males, less physically active participants, or those with preexisting cardiovascular diseases. Here, we show that MVPA timing may have the potential to improve public health.
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| 41. |
- Georgiev, Boris, et al.
(författare)
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A Universal Power-law Prescription for Variability from Synthetic Images of Black Hole Accretion Flows
- 2022
-
Ingår i: Astrophysical Journal Letters. - : American Astronomical Society. - 2041-8213 .- 2041-8205. ; 930:2
-
Tidskriftsartikel (refereegranskat)abstract
- We present a framework for characterizing the spatiotemporal power spectrum of the variability expected from the horizon-scale emission structure around supermassive black holes, and we apply this framework to a library of general relativistic magnetohydrodynamic (GRMHD) simulations and associated general relativistic ray-traced images relevant for Event Horizon Telescope (EHT) observations of Sgr A*. We find that the variability power spectrum is generically a red-noise process in both the temporal and spatial dimensions, with the peak in power occurring on the longest timescales and largest spatial scales. When both the time-averaged source structure and the spatially integrated light-curve variability are removed, the residual power spectrum exhibits a universal broken power-law behavior. On small spatial frequencies, the residual power spectrum rises as the square of the spatial frequency and is proportional to the variance in the centroid of emission. Beyond some peak in variability power, the residual power spectrum falls as that of the time-averaged source structure, which is similar across simulations; this behavior can be naturally explained if the variability arises from a multiplicative random field that has a steeper high-frequency power-law index than that of the time-averaged source structure. We briefly explore the ability of power spectral variability studies to constrain physical parameters relevant for the GRMHD simulations, which can be scaled to provide predictions for black holes in a range of systems in the optically thin regime. We present specific expectations for the behavior of the M87* and Sgr A* accretion flows as observed by the EHT.
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| 42. |
- Globisch, Maria A., et al.
(författare)
-
Immunothrombosis and vascular heterogeneity in cerebral cavernous malformation
- 2022
-
Ingår i: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 140:20, s. 2154-2169
-
Tidskriftsartikel (refereegranskat)abstract
- Cerebral cavernous malformation (CCM) is a neurovascular disease that results in various neurological symptoms. Thrombi have been reported in surgically resected CCM patient biopsies, but the molecular signatures of these thrombi remain elusive. Here, we investigated the kinetics of thrombi formation in CCM and how thrombi affect the vasculature and contribute to cerebral hypoxia. We used RNA sequencing to investigate the transcriptome of mouse brain endothelial cells with an inducible endothelial-specific Ccm3 knock-out (Ccm3-iECKO). We found that Ccm3-deficient brain endothelial cells had a higher expression of genes related to the coagulation cascade and hypoxia when compared with wild-type brain endothelial cells. Immunofluorescent assays identified key molecular signatures of thrombi such as fibrin, von Willebrand factor, and activated platelets in Ccm3-iECKO mice and human CCM biopsies. Notably, we identified polyhedrocytes in Ccm3-iECKO mice and human CCM biopsies and report it for the first time. We also found that the parenchyma surrounding CCM lesions is hypoxic and that more thrombi correlate with higher levels of hypoxia. We created an in vitro model to study CCM pathology and found that human brain endothelial cells deficient for CCM3 expressed elevated levels of plasminogen activator inhibitor-1 and had a redistribution of von Willebrand factor. With transcriptomics, comprehensive imaging, and an in vitro CCM preclinical model, this study provides experimental evidence that genes and proteins related to the coagulation cascade affect the brain vasculature and promote neurological side effects such as hypoxia in CCMs. This study supports the concept that antithrombotic therapy may be beneficial for patients with CCM.
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| 43. |
- Janssen, Michael, et al.
(författare)
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Event Horizon Telescope observations of the jet launching and collimation in Centaurus A
- 2021
-
Ingår i: Nature Astronomy. - : Springer Science and Business Media LLC. - 2397-3366. ; 5:10, s. 1017-1028
-
Tidskriftsartikel (refereegranskat)abstract
- Very-long-baseline interferometry (VLBI) observations of active galactic nuclei at millimetre wavelengths have the power to reveal the launching and initial collimation region of extragalactic radio jets, down to 10–100 gravitational radii (rg ≡ GM/c2) scales in nearby sources1. Centaurus A is the closest radio-loud source to Earth2. It bridges the gap in mass and accretion rate between the supermassive black holes (SMBHs) in Messier 87 and our Galactic Centre. A large southern declination of −43° has, however, prevented VLBI imaging of Centaurus A below a wavelength of 1 cm thus far. Here we show the millimetre VLBI image of the source, which we obtained with the Event Horizon Telescope at 228 GHz. Compared with previous observations3, we image the jet of Centaurus A at a tenfold higher frequency and sixteen times sharper resolution and thereby probe sub-lightday structures. We reveal a highly collimated, asymmetrically edge-brightened jet as well as the fainter counterjet. We find that the source structure of Centaurus A resembles the jet in Messier 87 on ~500 rg scales remarkably well. Furthermore, we identify the location of Centaurus A’s SMBH with respect to its resolved jet core at a wavelength of 1.3 mm and conclude that the source’s event horizon shadow4 should be visible at terahertz frequencies. This location further supports the universal scale invariance of black holes over a wide range of masses5,6.
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| 44. |
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| 45. |
- Jonason, Peter K., et al.
(författare)
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Country-level correlates of the Dark Triad traits in 49 countries
- 2020
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Ingår i: Journal of personality. - : Wiley. - 0022-3506 .- 1467-6494. ; 88:6, s. 1252-1267
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: The Dark Triad traits (i.e., narcissism, psychopathy, Machiavellianism) capture individual differences in aversive personality to complement work on other taxonomies, such as the Big Five traits. However, the literature on the Dark Triad traits relies mostly on samples from English-speaking (i.e., Westernized) countries. We broadened the scope of this literature by sampling from a wider array of countries.Method: We drew on data from 49 countries (N = 11,723; 65.8% female;Age(Mean) = 21.53) to examine how an extensive net of country-level variables in economic status (e.g., Human Development Index), social relations (e.g., gender equality), political orientations (e.g., democracy), and cultural values (e.g., embeddedness) relate to country-level rates of the Dark Triad traits, as well as variance in the magnitude of sex differences in them.Results: Narcissism was especially sensitive to country-level variables. Countries with more embedded and hierarchical cultural systems weremorenarcissistic. Also, sex differences in narcissism werelargerinmoredeveloped societies: Women were less likely to be narcissistic in developed (vs. less developed) countries.Conclusions: We discuss the results based on evolutionary and social role models of personality and sex differences. That higher country-level narcissism was more common in less developed countries, whereas sex differences in narcissism were larger in more developed countries, is more consistent with evolutionary than social role models.
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| 46. |
- Kim, Jae-Young, et al.
(författare)
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Event Horizon Telescope imaging of the archetypal blazar 3C 279 at an extreme 20 microarcsecond resolution
- 2020
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 640
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Tidskriftsartikel (refereegranskat)abstract
- 3C 279 is an archetypal blazar with a prominent radio jet that show broadband flux density variability across the entire electromagnetic spectrum. We use an ultra-high angular resolution technique - global Very Long Baseline Interferometry (VLBI) at 1.3mm (230 GHz) - to resolve the innermost jet of 3C 279 in order to study its fine-scale morphology close to the jet base where highly variable-ray emission is thought to originate, according to various models. The source was observed during four days in April 2017 with the Event Horizon Telescope at 230 GHz, including the phased Atacama Large Millimeter/submillimeter Array, at an angular resolution of ∼20 μas (at a redshift of z = 0:536 this corresponds to ∼0:13 pc ∼ 1700 Schwarzschild radii with a black hole mass MBH = 8 × 108 M⊙). Imaging and model-fitting techniques were applied to the data to parameterize the fine-scale source structure and its variation.We find a multicomponent inner jet morphology with the northernmost component elongated perpendicular to the direction of the jet, as imaged at longer wavelengths. The elongated nuclear structure is consistent on all four observing days and across diffierent imaging methods and model-fitting techniques, and therefore appears robust. Owing to its compactness and brightness, we associate the northern nuclear structure as the VLBI "core". This morphology can be interpreted as either a broad resolved jet base or a spatially bent jet.We also find significant day-to-day variations in the closure phases, which appear most pronounced on the triangles with the longest baselines. Our analysis shows that this variation is related to a systematic change of the source structure. Two inner jet components move non-radially at apparent speeds of ∼15 c and ∼20 c (∼1:3 and ∼1:7 μas day-1, respectively), which more strongly supports the scenario of traveling shocks or instabilities in a bent, possibly rotating jet. The observed apparent speeds are also coincident with the 3C 279 large-scale jet kinematics observed at longer (cm) wavelengths, suggesting no significant jet acceleration between the 1.3mm core and the outer jet. The intrinsic brightness temperature of the jet components are ≤1010 K, a magnitude or more lower than typical values seen at ≥7mm wavelengths. The low brightness temperature and morphological complexity suggest that the core region of 3C 279 becomes optically thin at short (mm) wavelengths.
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| 47. |
- Kurenkova, A. D., et al.
(författare)
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Notch Signaling Regulates the Chondrogenic Potential of Both Articular Chondrocytes and Their Progenitors During Expansion
- 2023
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Ingår i: Stem Cells. - 1066-5099. ; 41:6, s. 658-671
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Tidskriftsartikel (refereegranskat)abstract
- Articular cartilage has a limited capacity for self-repair and clinical approaches to cartilage regeneration are needed. The only such approach developed to date involves an expansion of primary autologous chondrocytes in culture, followed by their reimplantation into a cartilage defect. However, because of the formation of fibrocartilage instead of hyaline cartilage, the outcome is often not satisfactory. It happens due to the de-differentiation of chondrocytes during the expansion step. Indeed, articular chondrocytes are non-proliferative and require partial or complete dedifferentiation before actively proliferating. In recent years stem/progenitor cells in articular cartilage (artSPCs) have been described. These cells maintain their own population and renew articular cartilage in sexually mature mice. artSPCs can, theoretically, be superior to chondrocytes, for repairing damaged cartilage. Accordingly, here, we searched for conditions that allow rapid expansion of both artSPCs and chondrocytes with simultaneous preservation of their ability to form hyaline cartilage. Among the modulators of Wnt, Notch, and FGF signaling and of cell adhesion screened, only fibronectin and modulators of the Notch pathway promoted the rapid expansion of artSPCs. Surprisingly, both inhibition and activation of the pathway had this effect. However, only inhibition of Notch during expansion facilitated the chondrogenic potential of both artSPCs and primary chondrocytes, whereas activation of this pathway abrogated this potential entirely. This effect was the same for murine and human cells. Our present observations indicate that Notch signaling is the major regulator of the chondrogenic capacity of both artSPCs and chondrocytes during their expansion.
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| 48. |
- Lei, L., et al.
(författare)
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Beam Illumination Pattern Design in Satellite Networks : Learning and Optimization for Efficient Beam Hopping
- 2020
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Ingår i: IEEE Access. - : Institute of Electrical and Electronics Engineers (IEEE). - 2169-3536. ; 8, s. 136655-136667
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Tidskriftsartikel (refereegranskat)abstract
- Beam hopping (BH) is considered to provide a high level of flexibility to manage irregular and time-varying traffic requests in future multi-beam satellite systems. In BH optimization, adopting conventional iterative heuristics may have their own limitations in providing timely solutions, and directly using data-driven technique to approximate optimization variables may lead to constraint violation and degraded performance. In this paper, we explore a combined learning-and-optimization (LO) approach to provide an efficient, feasible, and near-optimal solution. The investigations are from the following aspects: 1) Integration of BH optimization and learning techniques; 2) Features to be learned in BH design; 3) How to address the feasibility issue incurred by machine learning. We provide numerical results and analysis to show that the learning component in LO significantly accelerates the procedure of identifying promising BH patterns, resulting in reduced computing time from seconds/minutes to milliseconds level. The identified learning feature enables high accuracy in predictions. In addition, the optimization component in LO guarantees the solution's feasibility and improves the overall performance with around 5% gap to the optimum.
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| 49. |
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| 50. |
- Li, Lianhui, et al.
(författare)
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Sustainability Assessment of Intelligent Manufacturing Supported by Digital Twin
- 2020
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Ingår i: IEEE Access. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 2169-3536. ; 8, s. 174988-175008
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Tidskriftsartikel (refereegranskat)abstract
- As a major challenge and opportunity for traditional manufacturing, intelligent manufacturing is facing the needs of sustainable development in future. Sustainability assessment undoubtedly plays a pivotal role for future development of intelligent manufacturing. Aiming at this, the paper presents the digital twin driven information architecture of sustainability assessment oriented for dynamic evolution under the whole life cycle based on the classic digital twin mapping system. The sustainability assessment method segment of the architecture includes indicator system building, indicator value determination, indicator importance degree determination and intelligent manufacturing project assessing. A novel approach for treating the ambiguity of expert judgment in indicator value determination by introducing trapezoidal fuzzy number into analytic hierarchy process is proposed, while the complexity of the influence relationship among the indicators is processed by the integration of complex networks modeling and PROMETHEE II for the indicator importance degree determination. A two-stage evidence combination model based on evidence theory is built for intelligent manufacturing project assessing lastly. The presented digital-twin-driven information architecture and the sustainability assessment method is tested and validated on a study of sustainability assessment of 8 intelligent manufacturing projects of an air conditioning enterprise. The results of the presented method were validated by comparing them with the results of the fuzzy and rough extension of the PROMETHEE II, TOPSIS and VIKOR methods, indicator importance degree determining method by entropy and indicator value determining method by accurate expert scoring.
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