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Sökning: WFRF:(Chen Qiang)

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  • 2019
  • Tidskriftsartikel (refereegranskat)
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4.
  • Beal, Jacob, et al. (författare)
  • Robust estimation of bacterial cell count from optical density
  • 2020
  • Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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5.
  • Klionsky, Daniel J., et al. (författare)
  • Guidelines for the use and interpretation of assays for monitoring autophagy
  • 2012
  • Ingår i: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
  • Forskningsöversikt (refereegranskat)abstract
    • In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
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6.
  • Kristanl, Matej, et al. (författare)
  • The Seventh Visual Object Tracking VOT2019 Challenge Results
  • 2019
  • Ingår i: 2019 IEEE/CVF INTERNATIONAL CONFERENCE ON COMPUTER VISION WORKSHOPS (ICCVW). - : IEEE COMPUTER SOC. - 9781728150239 ; , s. 2206-2241
  • Konferensbidrag (refereegranskat)abstract
    • The Visual Object Tracking challenge VOT2019 is the seventh annual tracker benchmarking activity organized by the VOT initiative. Results of 81 trackers are presented; many are state-of-the-art trackers published at major computer vision conferences or in journals in the recent years. The evaluation included the standard VOT and other popular methodologies for short-term tracking analysis as well as the standard VOT methodology for long-term tracking analysis. The VOT2019 challenge was composed of five challenges focusing on different tracking domains: (i) VOT-ST2019 challenge focused on short-term tracking in RGB, (ii) VOT-RT2019 challenge focused on "real-time" short-term tracking in RGB, (iii) VOT-LT2019 focused on long-term tracking namely coping with target disappearance and reappearance. Two new challenges have been introduced: (iv) VOT-RGBT2019 challenge focused on short-term tracking in RGB and thermal imagery and (v) VOT-RGBD2019 challenge focused on long-term tracking in RGB and depth imagery. The VOT-ST2019, VOT-RT2019 and VOT-LT2019 datasets were refreshed while new datasets were introduced for VOT-RGBT2019 and VOT-RGBD2019. The VOT toolkit has been updated to support both standard short-term, long-term tracking and tracking with multi-channel imagery. Performance of the tested trackers typically by far exceeds standard baselines. The source code for most of the trackers is publicly available from the VOT page. The dataset, the evaluation kit and the results are publicly available at the challenge website(1).
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7.
  • Akiyama, Kazunori, et al. (författare)
  • 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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8.
  • Bentham, James, et al. (författare)
  • A century of trends in adult human height
  • 2016
  • Ingår i: eLIFE. - 2050-084X. ; 5
  • Tidskriftsartikel (refereegranskat)abstract
    • Being taller is associated with enhanced longevity, and higher education and earnings. We reanalysed 1472 population-based studies, with measurement of height on more than 18.6 million participants to estimate mean height for people born between 1896 and 1996 in 200 countries. The largest gain in adult height over the past century has occurred in South Korean women and Iranian men, who became 20.2 cm (95% credible interval 17.522.7) and 16.5 cm (13.319.7) taller, respectively. In contrast, there was little change in adult height in some sub-Saharan African countries and in South Asia over the century of analysis. The tallest people over these 100 years are men born in the Netherlands in the last quarter of 20th century, whose average heights surpassed 182.5 cm, and the shortest were women born in Guatemala in 1896 (140.3 cm; 135.8144.8). The height differential between the tallest and shortest populations was 19-20 cm a century ago, and has remained the same for women and increased for men a century later despite substantial changes in the ranking of countries.
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9.
  • Bentham, James, et al. (författare)
  • A century of trends in adult human height
  • 2016
  • Ingår i: eLIFE. - : eLife Sciences Publications Ltd. - 2050-084X. ; 5
  • Tidskriftsartikel (refereegranskat)abstract
    • Being taller is associated with enhanced longevity, and higher education and earnings. We reanalysed 1472 population-based studies, with measurement of height on more than 18.6 million participants to estimate mean height for people born between 1896 and 1996 in 200 countries. The largest gain in adult height over the past century has occurred in South Korean women and Iranian men, who became 20.2 cm (95% credible interval 17.5–22.7) and 16.5 cm (13.3– 19.7) taller, respectively. In contrast, there was little change in adult height in some sub-Saharan African countries and in South Asia over the century of analysis. The tallest people over these 100 years are men born in the Netherlands in the last quarter of 20th century, whose average heights surpassed 182.5 cm, and the shortest were women born in Guatemala in 1896 (140.3 cm; 135.8– 144.8). The height differential between the tallest and shortest populations was 19-20 cm a century ago, and has remained the same for women and increased for men a century later despite substantial changes in the ranking of countries.
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11.
  • Kim, Jae-Young, et al. (författare)
  • Event Horizon Telescope imaging of the archetypal blazar 3C 279 at an extreme 20 microarcsecond resolution
  • 2020
  • Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 640
  • 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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12.
  • Algaba, Juan-Carlos, et al. (författare)
  • Broadband Multi-wavelength Properties of M87 during the 2017 Event Horizon Telescope Campaign
  • 2021
  • Ingår i: Astrophysical Journal Letters. - : American Astronomical Society. - 2041-8213 .- 2041-8205. ; 911:1
  • 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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13.
  • Chen, Fu qiang, et al. (författare)
  • Turbulent compressible flow analysis on multi-stage high pressure reducing valve
  • 2018
  • Ingår i: Flow Measurement and Instrumentation. - : Elsevier BV. - 0955-5986. ; 61, s. 26-37
  • Tidskriftsartikel (refereegranskat)abstract
    • Pressure reducing valve plays an important role in thermodynamic systems. Under extreme operating conditions, greater demands are requested on pressure reducing systems. In this paper, a novel multi-stage high pressure reducing valve (MSHPRV) is proposed, which can achieve multi-stage pressure reducing processes, improve the flow characteristics and deal with complex conditions. Here, the effects of different structural parameters on turbulent compressible flow inside MSHPRV are numerically investigated to achieve low valve noise and energy consumption. Mach number is taken as the parameter to reflect the fluid compressibility. Higher Mach number can cause serious aerodynamic noise and large amount of energy consumption. Based on this, transmission loss of MSHPRV is also studied to achieve better noise control performances. Meanwhile, larger turbulent dissipation rate means larger degree of energy consumption, so it is with the exergy loss. Thus, numerical models with different valve openings, perforated plate diameters, chamfer radii of perforated plates, pressure ratios and stages of perforated plates are established, and the effects of these structural parameters on the compressible turbulent flow and energy consumption of MSHPRV are investigated. Results show that different structural parameters have significant impacts on compressible turbulent flow and energy consumption performance in MSHPRV. The best noise control and least energy consumption of MSHPRV is achieved with such parameters as pressure ratio 7, perforated plate diameter 4 mm and 4 stage plates. This work can benefit the further research work on energy saving and multi-stage design of pressure reducing devices.
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14.
  • Chen, Zhi-Qiang, et al. (författare)
  • Leveraging breeding programs and genomic data in Norway spruce (Picea abies L. Karst) for GWAS analysis
  • 2021
  • Ingår i: Genome Biology. - : BioMed Central (BMC). - 1465-6906 .- 1474-760X. ; 22:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Genome-wide association studies (GWAS) identify loci underlying the variation of complex traits. One of the main limitations of GWAS is the availability of reliable phenotypic data, particularly for long-lived tree species. Although an extensive amount of phenotypic data already exists in breeding programs, accounting for its high heterogeneity is a great challenge. We combine spatial and factor-analytics analyses to standardize the heterogeneous data from 120 field experiments of 483,424 progenies of Norway spruce to implement the largest reported GWAS for trees using 134 605 SNPs from exome sequencing of 5056 parental trees.Results: We identify 55 novel quantitative trait loci (QTLs) that are associated with phenotypic variation. The largest number of QTLs is associated with the budburst stage, followed by diameter at breast height, wood quality, and frost damage. Two QTLs with the largest effect have a pleiotropic effect for budburst stage, frost damage, and diameter and are associated with MAP3K genes. Genotype data called from exome capture, recently developed SNP array and gene expression data indirectly support this discovery.Conclusion: Several important QTLs associated with growth and frost damage have been verified in several southern and northern progeny plantations, indicating that these loci can be used in QTL-assisted genomic selection. Our study also demonstrates that existing heterogeneous phenotypic data from breeding programs, collected over several decades, is an important source for GWAS and that such integration into GWAS should be a major area of inquiry in the future.
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15.
  • Danaei, Goodarz, et al. (författare)
  • Effects of diabetes definition on global surveillance of diabetes prevalence and diagnosis: a pooled analysis of 96 population-based studies with 331288 participants
  • 2015
  • Ingår i: The Lancet Diabetes & Endocrinology. - 2213-8595 .- 2213-8587. ; 3:8, s. 624-637
  • Tidskriftsartikel (refereegranskat)abstract
    • Background Diabetes has been defined on the basis of different biomarkers, including fasting plasma glucose (FPG), 2-h plasma glucose in an oral glucose tolerance test (2hOGTT), and HbA(1c). We assessed the effect of different diagnostic definitions on both the population prevalence of diabetes and the classification of previously undiagnosed individuals as having diabetes versus not having diabetes in a pooled analysis of data from population-based health examination surveys in different regions. Methods We used data from 96 population-based health examination surveys that had measured at least two of the biomarkers used for defining diabetes. Diabetes was defined using HbA(1c) (HbA(1c) >= 6 . 5% or history of diabetes diagnosis or using insulin or oral hypoglycaemic drugs) compared with either FPG only or FPG-or-2hOGTT definitions (FPG >= 7 . 0 mmol/L or 2hOGTT >= 11 . 1 mmol/L or history of diabetes or using insulin or oral hypoglycaemic drugs). We calculated diabetes prevalence, taking into account complex survey design and survey sample weights. We compared the prevalences of diabetes using different definitions graphically and by regression analyses. We calculated sensitivity and specificity of diabetes diagnosis based on HbA1c compared with diagnosis based on glucose among previously undiagnosed individuals (ie, excluding those with history of diabetes or using insulin or oral hypoglycaemic drugs). We calculated sensitivity and specificity in each survey, and then pooled results using a random-effects model. We assessed the sources of heterogeneity of sensitivity by meta-regressions for study characteristics selected a priori. Findings Population prevalence of diabetes based on FPG- or-2hOGTT was correlated with prevalence based on FPG alone (r= 0 . 98), but was higher by 2-6 percentage points at different prevalence levels. Prevalence based on HbA(1c) was lower than prevalence based on FPG in 42 . 8% of age-sex-survey groups and higher in another 41 . 6%; in the other 15 . 6%, the two definitions provided similar prevalence estimates. The variation across studies in the relation between glucose-based and HbA(1c)-based prevalences was partly related to participants' age, followed by natural logarithm of per person gross domestic product, the year of survey, mean BMI, and whether the survey population was national, subnational, or from specific communities. Diabetes defined as HbA(1c) 6 . 5% or more had a pooled sensitivity of 52 . 8% (95% CI 51 . 3-54 . 3%) and a pooled specificity of 99 . 74% (99 . 71-99 . 78%) compared with FPG 7 . 0 mmol/L or more for diagnosing previously undiagnosed participants; sensitivity compared with diabetes defined based on FPG-or-2hOGTT was 30 . 5% (28 . 7-32 . 3%). None of the preselected study-level characteristics explained the heterogeneity in the sensitivity of HbA(1c) versus FPG. Interpretation Different biomarkers and definitions for diabetes can provide different estimates of population prevalence of diabetes, and differentially identify people without previous diagnosis as having diabetes. Using an HbA(1c)-based definition alone in health surveys will not identify a substantial proportion of previously undiagnosed people who would be considered as having diabetes using a glucose-based test.
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16.
  • Gong, Hanmo, et al. (författare)
  • Gold nanoparticle transfer through photothermal effects in a metamaterial absorber by nanosecond laser
  • 2014
  • Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 4, s. 6080-
  • Tidskriftsartikel (refereegranskat)abstract
    • A non-complicated, controllable method of metallic nanoparticle fabrication at low operating light power is proposed. The method is based on laser-induced forward transfer, using a metamaterial absorber as the donor to significantly enhance the photothermal effect and reduce the operating light fluence to 35 mJ/cm(2), which is much lower than that in previous works. A large number of metallic nanoparticles can be transferred by one shot of focused nanosecond laser pulses. Transferred nanoparticles exhibit good size uniformity and the sizes are controllable. The optical properties of transferred particles are characterized by dark-field spectroscopy and the experimental results agree with the simulation results.
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17.
  • Gu, Qiang, et al. (författare)
  • VKORC1-1639G>A, CYP2C9, EPHX1691A>G genotype, body weight, and age are important predictors for warfarin maintenance doses in patients with mechanical heart valve prostheses in southwest China
  • 2010
  • Ingår i: European Journal of Clinical Pharmacology. - : Springer Science and Business Media LLC. - 0031-6970 .- 1432-1041. ; 66:12, s. 1217-1227
  • Tidskriftsartikel (refereegranskat)abstract
    • There were great interindividual differences in warfarin maintenance dosage (ranging from 0.6 to 8.4 mg/day) among the 127 patients with mechanical heart valve prostheses. VKORC1-1639G>A, CYP2C9, EPHX1691A>G polymorphism, body weight, and age were found to affect the dose demands. Multiple linear regression models incorporating genetic polymorphisms of VKORC1, CYP2C9, EPHX1691A>G, and the nongenetic factors of age and body weight were developed, and explained up to 76.8% of the total variation (adjusted R (2) of 0.743) in warfarin maintenance doses in southwest Chinese patients with mechanical heart valve prostheses.
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19.
  • Li, Qiang, et al. (författare)
  • Microbial Necromass, Lignin, and Glycoproteins for Determining and Optimizing Blue Carbon Formation
  • 2024
  • Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 58, s. 468-479
  • Tidskriftsartikel (refereegranskat)abstract
    • Coastal wetlands contribute to the mitigation of climate change through the sequestration of “blue carbon”. Microbial necromass, lignin, and glycoproteins (i.e., glomalin-related soil proteins (GRSP)), as important components of soil organic carbon (SOC), are sensitive to environmental change. However, their contributions to blue carbon formation and the underlying factors remain largely unresolved. To address this paucity of knowledge, we investigated their contributions to blue carbon formation along a salinity gradient in coastal marshes. Our results revealed decreasing contributions of microbial necromass and lignin to blue carbon as the salinity increased, while GRSP showed an opposite trend. Using random forest models, we showed that their contributions to SOC were dependent on microbial biomass and resource stoichiometry. In N-limited saline soils, contributions of microbial necromass to SOC decreased due to increased N-acquisition enzyme activity. Decreases in lignin contributions were linked to reduced mineral protection offered by short-range-ordered Fe (FeSRO). Partial least-squares path modeling (PLS-PM) further indicated that GRSP could increase microbial necromass and lignin formation by enhancing mineral protection. Our findings have implications for improving the accumulation of refractory and mineral-bound organic matter in coastal wetlands, considering the current scenario of heightened nutrient discharge and sea-level rise.
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20.
  • Lu, R.S., et al. (författare)
  • A ring-like accretion structure in M87 connecting its black hole and jet
  • 2023
  • Ingår i: Nature. - 0028-0836 .- 1476-4687. ; 616:7958, s. 686-690
  • Tidskriftsartikel (refereegranskat)abstract
    • The nearby radio galaxy M87 is a prime target for studying black hole accretion and jet formation1,2. Event Horizon Telescope observations of M87 in 2017, at a wavelength of 1.3 mm, revealed a ring-like structure, which was interpreted as gravitationally lensed emission around a central black hole3. Here we report images of M87 obtained in 2018, at a wavelength of 3.5 mm, showing that the compact radio core is spatially resolved. High-resolution imaging shows a ring-like structure of [Formula: see text] Schwarzschild radii in diameter, approximately 50% larger than that seen at 1.3 mm. The outer edge at 3.5 mm is also larger than that at 1.3 mm. This larger and thicker ring indicates a substantial contribution from the accretion flow with absorption effects, in addition to the gravitationally lensed ring-like emission. The images show that the edge-brightened jet connects to the accretion flow of the black hole. Close to the black hole, the emission profile of the jet-launching region is wider than the expected profile of a black-hole-driven jet, suggesting the possible presence of a wind associated with the accretion flow.
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21.
  • Qu, Yanhua, 1974-, et al. (författare)
  • The evolution of ancestral and species-specific adaptations in snowfinches at the Qinghai-Tibet Plateau
  • 2021
  • Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 10.1073/pnas.2012398118:13, s. e2012398118-e2012398118
  • Tidskriftsartikel (refereegranskat)abstract
    • Species in a shared environment tend to evolve similar adaptations under the influence of their phylogenetic context. Using snowfinches, a monophyletic group of passerine birds (Passeridae), we study the relative roles of ancestral and species-specific adaptations to an extreme high-elevation environment, the Qinghai–Tibet Plateau. Our ancestral trait reconstruction shows that the ancestral snowfinch occupied high elevations and had a larger body mass than most nonsnowfinches in Passeridae. Subsequently, this phenotypic adaptation diversified in the descendant species. By comparing high-quality genomes from representatives of the three phylogenetic lineages, we find that about 95% of genes under positive selection in the descendant species are different from those in the ancestor. Consistently, the biological functions enriched for these species differ from those of their ancestor to various degrees (semantic similarity values ranging from 0.27 to 0.5), suggesting that the three descendant species have evolved divergently from the initial adaptation in their common ancestor. Using a functional assay to a highly selective gene, DTL, we demonstrate that the nonsynonymous substitutions in the ancestor and descendant species have improved the repair capacity of ultraviolet-induced DNA damage. The repair kinetics of the DTL gene shows a twofold to fourfold variation across the ancestor and the descendants. Collectively, this study reveals an exceptional case of adaptive evolution to high-elevation environments, an evolutionary process with an initial adaptation in the common ancestor followed by adaptive diversification of the descendant species.
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22.
  • Zhou, Bin, et al. (författare)
  • Worldwide trends in diabetes since 1980: A pooled analysis of 751 population-based studies with 4.4 million participants
  • 2016
  • Ingår i: The Lancet. - : Elsevier B.V.. - 0140-6736 .- 1474-547X. ; 387:10027, s. 1513-1530
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: One of the global targets for non-communicable diseases is to halt, by 2025, the rise in the age standardised adult prevalence of diabetes at its 2010 levels. We aimed to estimate worldwide trends in diabetes, how likely it is for countries to achieve the global target, and how changes in prevalence, together with population growth and ageing, are aff ecting the number of adults with diabetes.Methods: We pooled data from population-based studies that had collected data on diabetes through measurement of its biomarkers. We used a Bayesian hierarchical model to estimate trends in diabetes prevalence-defined as fasting plasma glucose of 7.0 mmol/L or higher, or history of diagnosis with diabetes, or use of insulin or oral hypoglycaemic drugs-in 200 countries and territories in 21 regions, by sex and from 1980 to 2014. We also calculated the posterior probability of meeting the global diabetes target if post-2000 trends continue.Findings: We used data from 751 studies including 4372000 adults from 146 of the 200 countries we make estimates for. Global age-standardised diabetes prevalence increased from 4.3% (95% credible interval 2.4-17.0) in 1980 to 9.0% (7.2-11.1) in 2014 in men, and from 5.0% (2.9-7.9) to 7.9% (6.4-9.7) in women. The number of adults with diabetes in the world increased from 108 million in 1980 to 422 million in 2014 (28.5% due to the rise in prevalence, 39.7% due to population growth and ageing, and 31.8% due to interaction of these two factors). Age-standardised adult diabetes prevalence in 2014 was lowest in northwestern Europe, and highest in Polynesia and Micronesia, at nearly 25%, followed by Melanesia and the Middle East and north Africa. Between 1980 and 2014 there was little change in age-standardised diabetes prevalence in adult women in continental western Europe, although crude prevalence rose because of ageing of the population. By contrast, age-standardised adult prevalence rose by 15 percentage points in men and women in Polynesia and Micronesia. In 2014, American Samoa had the highest national prevalence of diabetes (>30% in both sexes), with age-standardised adult prevalence also higher than 25% in some other islands in Polynesia and Micronesia. If post-2000 trends continue, the probability of meeting the global target of halting the rise in the prevalence of diabetes by 2025 at the 2010 level worldwide is lower than 1% for men and is 1% for women. Only nine countries for men and 29 countries for women, mostly in western Europe, have a 50% or higher probability of meeting the global target.Interpretation: Since 1980, age-standardised diabetes prevalence in adults has increased, or at best remained unchanged, in every country. Together with population growth and ageing, this rise has led to a near quadrupling of the number of adults with diabetes worldwide. The burden of diabetes, both in terms of prevalence and number of adults aff ected, has increased faster in low-income and middle-income countries than in high-income countries.
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23.
  • Akiyama, Kazunori, et al. (författare)
  • 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*
  •  
24.
  • Akiyama, Kazunori, et al. (författare)
  • 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.
  •  
25.
  • Akiyama, Kazunori, et al. (författare)
  • 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.
  •  
26.
  • Baison, John, et al. (författare)
  • Genome-wide association study identified novel candidate loci affecting wood formation in Norway spruce
  • 2019
  • Ingår i: The Plant Journal. - : John Wiley & Sons. - 0960-7412 .- 1365-313X. ; 100:1, s. 83-100
  • Tidskriftsartikel (refereegranskat)abstract
    • Norway spruce is a boreal forest tree species of significant ecological and economic importance. Hence there is a strong imperative to dissect the genetics underlying important wood quality traits in the species. We performed a functional genome-wide association study (GWAS) of 17 wood traits in Norway spruce using 178 101 single nucleotide polymorphisms (SNPs) generated from exome genotyping of 517 mother trees. The wood traits were defined using functional modelling of wood properties across annual growth rings. We applied a Least Absolute Shrinkage and Selection Operator (LASSO-based) association mapping method using a functional multilocus mapping approach that utilizes latent traits, with a stability selection probability method as the hypothesis testing approach to determine a significant quantitative trait locus. The analysis provided 52 significant SNPs from 39 candidate genes, including genes previously implicated in wood formation and tree growth in spruce and other species. Our study represents a multilocus GWAS for complex wood traits in Norway spruce. The results advance our understanding of the genetics influencing wood traits and identifies candidate genes for future functional studies.
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27.
  • Boström, Ola, et al. (författare)
  • Writing a handbook of vehicle safety measures
  • 2013
  • Ingår i: Proceedings of the 16th International Conference Road Safety on Four Continents. - Linköping : Statens väg- och transportforskningsinstitut.
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • This paper describes the development of a handbook intended to increase the common Chinese knowledge of safety features in today’s cars. The handbook is the result of the joint effort of China based CATARC and Autoliv China as well as Sweden based Chalmers University and Autoliv Research. The origin and basis of the handbook is the master thesis work by the Chalmers student Jing Li.It is known from the introduction section that road traffic safety is a big issue at global levels for it is a leading factor for fatalities. The problem in China is serious since the number of vehicles on the roads grows fast, which means it is more likely to be exposed to road accidents and the safety countermeasures and people’s safety awareness fail to catch up with the increasing traffic. This project work is done following the methods of literature review, telephone interviews with Chinese people, accident data research, and Madymo simulations for common but dangerous situations. It is to combine the techniques and the real situations, which are totally different from Sweden, to make the techniques serve more people. Through these methods, the handbook of vehicle safety measures is developed.
  •  
28.
  • Broderick, Avery E., et al. (författare)
  • 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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29.
  • Chen, David, et al. (författare)
  • CHANGE-POINT ALTERATIONS OF EXTREME WATER LEVELS AND UNDERLYING CAUSES IN THE PEARL RIVER DELTA, CHINA
  • 2009
  • Ingår i: Rivers Research and Applications. - : Wiley. - 1535-1459 .- 1535-1467. ; 25, s. 1153-1168
  • Tidskriftsartikel (refereegranskat)abstract
    • In this paper, the Bayesian model and Lepage test were used to detect change point and to analyse associated statistical properties of high/low water levels in summer (June, July and August (JJA)) and winter (December, January and February (DJF)) months across the PRD (Pearl River Delta). The results indicate that: (1) two time intervals, that is 1979-1981 and 1988-1995, witness abrupt changes of SmH/SmL (summer mean high water level/summer mean low water level). The lower PRD is dominated by increased mean and coefficient of variation (Cv) of SmH. Increased mean but decreased Cv of SmL can be observed in the Mainstem Pearl River; (2) WmL (winter mean low water level) and WmH (winter mean high water level) of about 74% of the total stations have two change points occurred roughly during 1969-1971 and 1993-1995. First change points of WmH are mainly characterized by increased mean and Cv, but decreased mean and increased Cv of WmL can be observed across major parts of the PRD. The driving factors causing abrupt changes of water levels are various. Intensive human activities cannot be ignored, for example in-channel dredging and reallocation of the streamflow within the river channels due to human-induced topographical changes of river channel. Different responses of high/low water levels to externally influencing factors and interactions between influencing factors make the alterations of the water levels across the PRD more complicated. The findings of this paper will be helpful for the management of the PRD and human mitigation to natural hazards under the changing environment. Copyright (C) 2008 John Wiley & Sons, Ltd.
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30.
  • Chen, David, et al. (författare)
  • Hydrologic alteration along the Middle and Upper East River (Dongjiang) basin, South China : a visually enhanced mining on the results of RVA method
  • 2010
  • Ingår i: Stochastic environmental research and risk assessment (Print). - : Springer Science and Business Media LLC. - 1436-3240 .- 1436-3259. ; 24, s. 9-18
  • Tidskriftsartikel (refereegranskat)abstract
    • This paper presents a visually enhanced evaluation of the spatio-temporal patterns of the dam-induced hydrologic alteration in the middle and upper East River, south China over 1952-2002, using the range of variability approach (RVA) and visualization package XmdvTool. The impacts of climate variability on hydrological processes have been removed for wet and dry periods, respectively, so that we focus on the impacts of human activities (i.e., dam construction). The results indicate that: (1) along the East River, dams have greatly altered the natural flow regime, range condition and spatial variability; (2) six most remarkable indicators of hydrologic alteration induced by dam-construction are rise rate (1.16), 3-day maximum (0.91), low pulse duration (0.88), January (0.80), July (0.80) and February (0.79) mean flow of the East River during 1952-2002; and (3) spatiotemporal hydrologic alterations are different among three stations along Easter River. Under the influence of dam construction in the upstream, the degree of hydrologic changes from Lingxia, Heyuan to Longchuan station increases. This study reveals that visualization techniques for high-dimensional hydrological datasets together with RVA are beneficial for detecting spatio-temporal hydrologic changes.
  •  
31.
  • Chen, Fu qiang, et al. (författare)
  • Pressure analysis on two-step high pressure reducing system for hydrogen fuel cell electric vehicle
  • 2017
  • Ingår i: International Journal of Hydrogen Energy. - : Elsevier BV. - 0360-3199. ; 42:16, s. 11541-11552
  • Tidskriftsartikel (refereegranskat)abstract
    • Hydrogen fuel cell electric vehicle (FCEV) can achieve zero exhaust emission and zero pollution. In order to make FCEV reach a farther travel distance, greater demands are put on its pressure reducing system. In this paper, a two-step high pressure reducing system for FCEV is proposed. The system is made up of two parts, a new high multi-stage pressure reducing valve (HMSPRV) and a multi-stage muffler. As a new system, its feasibility has to be verified. Since the valve opening condition has a great effect on hydrogen flow, pressure reduction and energy consumption, different valve opening conditions are taken as the research point. The flow field analysis of the new HMSPRV is conducted on three aspects: pressure field, velocity field and energy consumption. It can be found that both the pressure reducing and velocity increasing gradients mainly reflect at those throttling components for all valve openings. For energy consumption, in the comprehensive study of flow vortexes and turbulent dissipation rate, it can be found that the larger of the valve opening, the larger of energy consumption. Then, a thermo-fluid-solid coupling analysis is conducted on the new HMSPRV, and it is concluded that the new system meets strength requirement. Furthermore, as the second step of the high pressure reducing system, the flow and pressure fields of multi-stage muffler are investigated. The five-stage muffler is exactly designed to complete the whole pressure reducing process. This study can provide technological support for achieving pressure regulation in the hydrogen transport system of FCEV when facing complex conditions, and it can also benefit the further research work on energy saving and multi-stage flow of pressure reducing devices.
  •  
32.
  • Chen, Fu qiang, et al. (författare)
  • Thermo-mechanical stress and fatigue damage analysis on multi-stage high pressure reducing valve
  • 2017
  • Ingår i: Annals of Nuclear Energy. - : Elsevier BV. - 0306-4549. ; 110, s. 753-767
  • Tidskriftsartikel (refereegranskat)abstract
    • A multi-stage high pressure reducing valve (MSHPRV) is proposed. It can achieve a multi-stage pressure reducing way. Valve failure mainly occurs under high pressure and high temperature conditions, thus it is necessary to investigate the strength of MSHPRV under those complex conditions. In this paper, the mathematical model of MSHPRV is established and Computational Fluid Dynamics (CFD) method is employed to simulate its flow fields and thermo-mechanical stress. Next, the stress of MSHPRV under different opening time and the fatigue damage of MSHPRV under different valve openings are studied. Finally, two changes are provided on geometry of MSHPRV and the geometrical factors are optimized. The results show that, the radial direction from inner wall to outer wall is the main heat transfer direction for valve body. At opening time 50 s, the working condition of MSHPRV is dangerous condition. Meanwhile, the maximum value of thermal stress is 487 MPa, which is located at the upper end face of valve chamber region B3. There is a lag effect of stress distribution with respect to temperature distribution. The combined stress of valve body is composed of thermal stress and mechanical stress, in which thermal stress holds the dominant position. Moreover, with the increasing of valve opening, the fatigue damage of valve body increases correspondingly. It can be concluded that MSHPRV can cope with complex conditions like high pressure and high temperature. In the optimization design of MSHPRV, it can be found that the best strength of MSHPRV is achieved with such geometrical factors as angle 15, diameter 4 mm and 2 stage plates. Besides, radian design as the improved structure is recommended. This work can benefit the further research work on the regulation performance and safe operation of high pressure reducing valve.
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33.
  • Chen, Xuelong, et al. (författare)
  • Investigation of Precipitation Process in the Water Vapor Channel of the Yarlung Zsangbo Grand Canyon
  • 2024
  • Ingår i: BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY. - 0003-0007 .- 1520-0477. ; 105:2
  • Tidskriftsartikel (refereegranskat)abstract
    • The Yarlung Zsangbo Grand Canyon (YGC) is an important pathway for water vapor transport from southern Asia to the Tibetan Plateau (TP). This area exhibits one of the highest frequencies of convective activity in China, and precipitation often induces natural disasters in local communities, which can dramatically affect their livelihoods. In addition, the produced precipitation gives rise to vast glaciers and large rivers around the YGC. In 2018, the Second Tibetan Plateau Scientific Expedition and Research Program tasked a research team to conduct an "investigation of the precipitation process in the water vapor channel of the Yarlung Zsangbo Grand Canyon" (INVC) in the southeastern TP. This team subsequently established a comprehensive observation system of land-air interaction, water vapor, clouds, and rainfall activity in the YGC. This paper introduces the developed observation system and summarizes the preliminary results obtained during the first two years of the project. Using this INVC observation network, herein, we focus on the development of rainfall events on the southeastern TP. This project also helps to monitor geohazards in the key area of the Sichuan-Tibet railway, which traverses the northern YGC. The observation datasets will benefit future research on mountain meteorology.
  •  
34.
  • Chen, Xi, et al. (författare)
  • Ordered Au nanocrystals on a substrate formed by light-induced rapid annealing
  • 2014
  • Ingår i: Nanoscale. - : Royal Society of Chemistry (RSC). - 2040-3364 .- 2040-3372. ; 6:3, s. 1756-1762
  • Tidskriftsartikel (refereegranskat)abstract
    • Light-induced rapid annealing (LIRA) is a widely used method to modify the morphology and crystallinity of noble metal nanoparticles, and the nanoparticles generally evolve into nanospheres. It is rather challenging to form faceted Au nanocrystals on a substrate using LIRA. Here the formation of spatially ordered Au nanocrystals using a continuous wave infrared laser is reported, assisted by a metamaterial perfect absorber. Faceted Au nanocrystals in truncated-octahedral or multi-twinned geometries can be obtained. The evolution of morphology and crystallinity of the Au nanoparticles during laser annealing is also revealed, where the crystal grain growth and the surface melting are shown to play key roles in nanocrystal formation. The evolution of morphology also gives the freedom of tuning the absorption spectrum of the metamaterial absorber. These findings provide a novel way for tailoring the morphology and crystallinity of metallic nanoparticles and may pave the way to fabricate refined nano-devices in many potential applications for optics, electronics, catalysis, surface-chemistry and biology.
  •  
35.
  • Chen, Zhi-Qiang, et al. (författare)
  • Estimating solid wood properties using Pilodyn and acoustic velocity on standing trees of Norway spruce
  • 2015
  • Ingår i: Annals of Forest Science. - : Springer Science and Business Media LLC. - 1286-4560 .- 1297-966X. ; 72:4, s. 499-508
  • Tidskriftsartikel (refereegranskat)abstract
    • Key message: Strong genetic correlations were observed between Pilodyn measurement and wood density, and between acoustic velocity and MFA. Combination of Pilodyn penetration and acoustic velocity measurements from standing trees can provide reliable prediction of stiffness of Norway spruce for breeding selection.Context: Traditional methods for the estimation of solid wood quality traits of standing tree such as wood density, microfibril angle (MFA), and modulus of elasticity (MOE) are time-consuming and expensive, which render them unsuitable for rapidly screening a large number of trees in tree breeding programs.Aim: This study aims to evaluate the suitability of using Pilodyn penetration and acoustic velocity (nondestructive evaluation) to assess wood density, MFA, and MOE for Norway spruce.Methods: Pilodyn penetration and Hitman acoustic velocity, as well as wood density, MFA, and MOE using benchmark SilviScan were measured on 5618 standing trees of 524 open-pollinated families in two 21-year-old Norway spruce (Picea abies) progeny trials in southern Sweden.Results: Strong genetic correlations were observed between Pilodyn measurement and wood density (rg = −0.96), and between acoustic velocity and MFA (rg = −0.94). Combination of Pilodyn penetration and Hitman acoustic velocity measurements (Formula presented.) obtained from standing trees showed a genetic correlation with benchmark MOE of 0.99. This combined MOE(Formula presented.) had higher selection efficiency for benchmark MOE (92 %) compared to 58–60 % using acoustic velocity alone and 78 % using Pilodyn penetration alone.Conclusion: Combination of Pilodyn penetration with Hitman acoustic velocity provided very high selection efficiency for the three most important quality traits for wood mechanical properties in Norway spruce.
  •  
36.
  • Chen, Zhi-Qiang, et al. (författare)
  • Genetic analysis of fiber dimensions and their correlation with stem diameter and solid-wood properties in Norway spruce
  • 2016
  • Ingår i: Tree Genetics & Genomes. - : Springer Science and Business Media LLC. - 1614-2942 .- 1614-2950. ; 12:6
  • Tidskriftsartikel (refereegranskat)abstract
    • Adverse genetic correlations between growth traits and solid-wood, as well as fiber traits are a concern in conifer breeding programs. To evaluate the impact of selection for growth and solid-wood properties on fiber dimensions, we investigated the inheritance and efficiency of early selection for different wood-fiber traits and their correlations with stem diameter, wood density, modulus of elasticity (MOE), and microfibril angle (MFA) in Norway spruce (Picea abies L). The study was based on two large open-pollinated progeny trials established in southern Sweden in 1990 with material from 524 families comprising 5618 trees. Two increment cores were sampled from each tree. Radial variations from pith to bark were determined for rings 3–15 with SilviScan for fiber widths in the radial (RFW) and tangential (TFW) direction, fiber wall thickness (FWT), and fiber coarseness (FC). Fiber length (FL) was determined for rings 8–11. Heritabilities based on rings 8–11 using joint-site data were moderate to high (0.24–0.51) for all fiber-dimension traits. Heritabilities based on stem cross-sectional averages varied from 0.34 to 0.48 and reached a plateau at rings 6–9. The “age-age” genetic correlations for RFW, TFW, FWT, and FC cross-sectional averages at a particular age with cross-sectional averages at ring 15 reached 0.9 at rings 4–7. Our results indicated a moderate to high positive genetic correlation for density and MOE with FC and FWT, moderate and negative with RFW, and low with TFW and FL. Comparison of several selection scenarios indicated that the highest profitability is reached when diameter and MOE are considered jointly, in which case, the effect on any fiber dimension is negligible. Early selection was highly efficient from ring 5 for RFW and from rings 8–10 for TFW, FWT, and FC.
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37.
  • Eatough, Ralph P., et al. (författare)
  • 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.
  •  
38.
  • Fu, Pan, et al. (författare)
  • Metasurface Enabled On-Chip Generation and Manipulation of Vector Beams from Vertical Cavity Surface-Emitting Lasers
  • 2023
  • Ingår i: Advanced Materials. - : Wiley. - 0935-9648 .- 1521-4095. ; In Press
  • Tidskriftsartikel (refereegranskat)abstract
    • Metasurface polarization optics that consist of 2D array of birefringent nano-antennas have proven remarkable capabilities to generate and manipulate vectorial fields with subwavelength resolution and high efficiency. Integrating this new type of metasurface with the standard vertical cavity surface-emitting laser (VCSEL) platform enables an ultracompact and powerful solution to control both phase and polarization properties of the laser on a chip, which allows to structure a VCSEL into vector beams with on-demand wavefronts. Here, this concept is demonstrated by directly generating versatile vector beams from commercially available VCSELs through on-chip integration of high-index dielectric metasurfaces. Experimentally, the versatility of the approach for the development of vectorial VCSELs are validated by implementing a variety of functionalities, including directional emission of multibeam with specified polarizations, vectorial holographic display, and vector vortex beams generations. Notably, the proposed vectorial VCSELs integrated with a single layer of beam shaping metasurface bypass the requirements of multiple cascaded optical components, and thus have the potential to promote the advancements of ultracompact, lightweight, and scalable vector beams sources, enriching and expanding the applications of VCSELs in optical communications, laser manipulation and processing, information encryption, and quantum optics.
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39.
  • Georgiev, Boris, et al. (författare)
  • 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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40.
  • Gu, Jian, et al. (författare)
  • TGF-beta-Induced CD4(+) Foxp3(+) T Cells Attenuate Acute Graft-versus-Host Disease by Suppressing Expansion and Killing of Effector CD8(+) Cells
  • 2014
  • Ingår i: Journal of Immunology. - : The American Association of Immunologists. - 0022-1767 .- 1550-6606. ; 193:7, s. 3388-3397
  • Tidskriftsartikel (refereegranskat)abstract
    • The use of TGF-beta-induced CD4(+) Foxp3(+) T cells (induced regulatory T cells [iTregs]) is an important prevention and treatment strategy in autoimmune diseases and other disorders. However, the potential use of iTregs as a treatment modality for acute graft-versus-host disease (aGVHD) has not been realized because they may be unstable and less suppressive in this disease. We restudied the ability of iTregs to prevent and treat aGVHD in two mouse models. Our results showed that, as long as an appropriate iTreg-generation protocol is used, these iTregs consistently displayed a potent ability to control aGVHD development and reduce mortality in the aGVHD animal models. iTreg infusion markedly suppressed the engraftment of donor CD8(+) cells and CD4(+) cells, the expression of granzyme A and B, the cytotoxic effect of donor CD8(+) cells, and the production of T cell cytokines in aGVHD. Therefore, we conclude that as long as the correct methods for generating iTregs are used, they can prevent and even treat aGVHD.
  •  
41.
  • Janssen, Michael, et al. (författare)
  • 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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42.
  • Jun, Chen, et al. (författare)
  • A Novel Acceleration Data Compression Scheme for Wireless Sensor Network Application in Fresh Food Tracking System
  • 2009
  • Ingår i: The Ninth International Conference on Electronic Measurement &amp; Instruments ICEMI’2009. - : IEEE Press. - 9781424438631 ; , s. 3-1-3-5
  • Konferensbidrag (refereegranskat)abstract
    • An enhanced dual-layer wide area wireless sensor network (WSN) system was developed and applied in fresh food tracking application. The sensor nodes of WSN provide a set of useful measurements about the environmental conditions during the fresh food transportation. Since the 3-axis acceleration data in such application account for more than 99% out of all collected source data, we propose a novel acceleration data compression scheme for this specific application, to overcome the resource and cost limitation imposed on embedded sensing nodes and wireless communication links in WSN. According to general fresh food transport behavior pattern, the acceleration data can be extracted into three components (D waveform, A waveform and P waveform). Each component could be compressed separately according to its distinct characteristic and then packetized as an encoded frame. In this paper we examine the experimental acceleration dataset from a field test (fresh melon fruit transport from Brazil to Sweden in 20 days) as a test case. Experimental results show that a high compression ratio (around 10:1) with the acceptable distortion could be achieved, confirming the effectiveness of the compression scheme proposed in this work.
  •  
43.
  • Kristan, Matej, et al. (författare)
  • The Sixth Visual Object Tracking VOT2018 Challenge Results
  • 2019
  • Ingår i: Computer Vision – ECCV 2018 Workshops. - Cham : Springer Publishing Company. - 9783030110086 - 9783030110093 ; , s. 3-53
  • Konferensbidrag (refereegranskat)abstract
    • The Visual Object Tracking challenge VOT2018 is the sixth annual tracker benchmarking activity organized by the VOT initiative. Results of over eighty trackers are presented; many are state-of-the-art trackers published at major computer vision conferences or in journals in the recent years. The evaluation included the standard VOT and other popular methodologies for short-term tracking analysis and a “real-time” experiment simulating a situation where a tracker processes images as if provided by a continuously running sensor. A long-term tracking subchallenge has been introduced to the set of standard VOT sub-challenges. The new subchallenge focuses on long-term tracking properties, namely coping with target disappearance and reappearance. A new dataset has been compiled and a performance evaluation methodology that focuses on long-term tracking capabilities has been adopted. The VOT toolkit has been updated to support both standard short-term and the new long-term tracking subchallenges. Performance of the tested trackers typically by far exceeds standard baselines. The source code for most of the trackers is publicly available from the VOT page. The dataset, the evaluation kit and the results are publicly available at the challenge website (http://votchallenge.net).
  •  
44.
  • Kristan, Matej, et al. (författare)
  • The Visual Object Tracking VOT2015 challenge results
  • 2015
  • Ingår i: Proceedings 2015 IEEE International Conference on Computer Vision Workshops ICCVW 2015. - : IEEE. - 9780769557205 ; , s. 564-586
  • Konferensbidrag (refereegranskat)abstract
    • The Visual Object Tracking challenge 2015, VOT2015, aims at comparing short-term single-object visual trackers that do not apply pre-learned models of object appearance. Results of 62 trackers are presented. The number of tested trackers makes VOT 2015 the largest benchmark on short-term tracking to date. For each participating tracker, a short description is provided in the appendix. Features of the VOT2015 challenge that go beyond its VOT2014 predecessor are: (i) a new VOT2015 dataset twice as large as in VOT2014 with full annotation of targets by rotated bounding boxes and per-frame attribute, (ii) extensions of the VOT2014 evaluation methodology by introduction of a new performance measure. The dataset, the evaluation kit as well as the results are publicly available at the challenge website(1).
  •  
45.
  • Kristan, Matej, et al. (författare)
  • The Visual Object Tracking VOT2017 challenge results
  • 2017
  • Ingår i: 2017 IEEE INTERNATIONAL CONFERENCE ON COMPUTER VISION WORKSHOPS (ICCVW 2017). - : IEEE. - 9781538610343 ; , s. 1949-1972
  • Konferensbidrag (refereegranskat)abstract
    • The Visual Object Tracking challenge VOT2017 is the fifth annual tracker benchmarking activity organized by the VOT initiative. Results of 51 trackers are presented; many are state-of-the-art published at major computer vision conferences or journals in recent years. The evaluation included the standard VOT and other popular methodologies and a new "real-time" experiment simulating a situation where a tracker processes images as if provided by a continuously running sensor. Performance of the tested trackers typically by far exceeds standard baselines. The source code for most of the trackers is publicly available from the VOT page. The VOT2017 goes beyond its predecessors by (i) improving the VOT public dataset and introducing a separate VOT2017 sequestered dataset, (ii) introducing a realtime tracking experiment and (iii) releasing a redesigned toolkit that supports complex experiments. The dataset, the evaluation kit and the results are publicly available at the challenge website(1).
  •  
46.
  •  
47.
  • Li, Suyang, et al. (författare)
  • Highly homogeneous bimetallic core-shell Au@Ag nanoparticles with embedded internal standard fabrication using a microreactor for reliable quantitative SERS detection
  • 2023
  • Ingår i: Materials Chemistry Frontiers. - : Royal Society of Chemistry (RSC). - 2052-1537. ; 7:6, s. 1100-1109
  • Tidskriftsartikel (refereegranskat)abstract
    • Bimetallic gold core-silver shell (Au@Ag) surface-enhanced Raman scattering tags draw broad interest in the fields of biological and environmental analyses. Herein, an efficient hybrid microfluidic chip was designed to prepare uniform Au@Ag core-shell nanoparticles, and DTNB was used as the internal standard tag molecule to prepare Au@DTNB@Ag for SERS detection. Homogeneous core-shell nanoparticles with a particle size of 90 nm were prepared by mixing a silver precursor and a gold core in a microfluidic chip. The relative standard deviation (RSD) of the particle size distribution was close to 10%, and the detection limit of 4-MBA was as low as 10-10 M. In order to solve the influence of SERS signal fluctuation, a uniform Au@DTNB@Ag core-molecule-shell structure was synthesized in a microfluidic chip, and the characteristic peak of the analyte was corrected by the relative intensity of the DTNB characteristic peak (1335 cm−1). The experimental results showed that the SERS detection was achieved with high reproducibility, and the SERS peak intensity had a good linear correlation with the concentration. The homogeneous SERS substrate prepared using a microfluidic chip has potential for sensitive and reliable detection of environmental chemical contaminants.
  •  
48.
  • Ma, Tao, et al. (författare)
  • Genomic insights into salt adaptation in a desert poplar
  • 2013
  • Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 4, s. 2797-
  • Tidskriftsartikel (refereegranskat)abstract
    • Despite the high economic and ecological importance of forests, our knowledge of the genomic evolution of trees under salt stress remains very limited. Here we report the genome sequence of the desert poplar, Populus euphratica, which exhibits high tolerance to salt stress. Its genome is very similar and collinear to that of the closely related mesophytic congener, P. trichocarpa. However, we find that several gene families likely to be involved in tolerance to salt stress contain significantly more gene copies within the P. euphratica lineage. Furthermore, genes showing evidence of positive selection are significantly enriched in functional categories related to salt stress. Some of these genes, and others within the same categories, are significantly upregulated under salt stress relative to their expression in another salt-sensitive poplar. Our results provide an important background for understanding tree adaptation to salt stress and facilitating the genetic improvement of cultivated poplars for saline soils.
  •  
49.
  • Marcotte, Harold, et al. (författare)
  • Conversion of monoclonal IgG to dimeric and secretory IgA restores neutralizing ability and prevents Infection of Omicron lineages
  • 2024
  • Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : NATL ACAD SCIENCES. - 0027-8424 .- 1091-6490. ; 121:3
  • Tidskriftsartikel (refereegranskat)abstract
    • The emergence of Omicron lineages and descendent subvariants continues to present a severe threat to the effectiveness of vaccines and therapeutic antibodies. We have previ- ously suggested that an insufficient mucosal immunoglobulin A (IgA) response induced by the mRNA vaccines is associated with a surge in breakthrough infections. Here, we further show that the intramuscular mRNA and/or inactivated vaccines cannot suffi- ciently boost the mucosal secretory IgA response in uninfected individuals, particu- larly against the Omicron variant. We thus engineered and characterized recombinant monomeric, dimeric, and secretory IgAl antibodies derived from four neutralizing IgG monoclonal antibodies (mAbs 01A05, rmAb23, DXP-604, and XG014) targeting the receptor-binding domain of the spike protein. Compared to their parental IgG antibod- ies, dimeric and secretory IgAl antibodies showed a higher neutralizing activity against different variants of concern (VOCs), in part due to an increased avidity. Importantly, the dimeric or secretory IgAl form of the DXP-604 antibody significantly outperformed its parental IgG antibody, and neutralized the Omicron lineages BA.1, BA.2, and BA.4/5 with a 25- to 75-fold increase in potency. In human angiotensin converting enzyme 2 (ACE2) transgenic mice, a single intranasal dose of the dimeric IgA DXP-604 conferred prophylactic and therapeutic protection against Omicron BA.5. Thus, dimeric or secre- tory IgA delivered by nasal administration may potentially be exploited for the treatment Iand prevention of Omicron infection, thereby providing an alternative tool for combating immune evasion by the current circulating subvariants and, potentially, future VOCs.
  •  
50.
  • Pang, Zhibo, et al. (författare)
  • Global Fresh Food Tracking Service Enabled by Wide Area Wireless Sensor Network
  • 2010
  • Ingår i: 2010 IEEE Sensors Applications Symposium, SAS 2010. - : IEEE Sensors Council. ; , s. 6-9
  • Konferensbidrag (refereegranskat)abstract
    • A global fresh food tracking service is presented, in which a set of primary environmental conditions for transport of fresh fruits and vegetables, including global position, temperature, relative humidity, concentrations of CO2, O2 and ethylene gases and 3-axis acceleration, is collected through mobile and remotely controllable wireless sensor nodes. Real time monitoring, tracking, alarming, close-loop controlling and information sharing could therefore be provided as WEB services with service oriented architecture. Fully functioned hardware modules, protocols and system software have been developed. A 50-day field test has been successfully carried out, proving the system concept and the robustness of hardware and software designed. Due to its worldwide deploy-ability and added-values to fresh food supply chain, it is feasible to establish a practical fresh food tracking service business.
  •  
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