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| 2. |
- Beal, Jacob, et al.
(författare)
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Robust estimation of bacterial cell count from optical density
- 2020
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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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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| 3. |
- Chang, Yachao, et al.
(författare)
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Construction and assessment of reduced oxidation mechanisms using global sensitivity analysis and uncertainty analysis
- 2019
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Ingår i: Proceedings of the Combustion Institute. - : Elsevier BV. - 1540-7489. ; 37:1, s. 751-761
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Tidskriftsartikel (refereegranskat)abstract
- The global sensitivity analysis is an effective method to assess the performance of a chemical reaction mechanism. In the present study, the uncertainty analysis and the global sensitivity analysis of a detailed chemical mechanism of n-heptane are first performed based on the Monte Carlo method. The source of the prediction uncertainties of the C0-C7 sub-mechanisms and the reaction classes in the fuel-specific sub-mechanism of the detailed mechanism are determined by the global sensitivity analysis. Then, based on the results, a reduced mechanism for n-heptane oxidation is developed. To assess the performance of the reduced mechanism, the nominal model prediction and the frequency distribution of the ignition delay times using the present reduced mechanism are compared with those of the detailed mechanism and two additional reduced mechanisms obtained by the directed relation graph with error propagation (DRGEP) method. The results indicate that the predictions from the present reduced mechanism and the reduced mechanism with 305 species satisfactorily agree that of the detailed mechanism. Furthermore, the discrepancy of the predictions among these mechanisms is discussed based on the Spearman Rank Correlation analysis. It is found that, for the reduced mechanism with 120 species, the optimization of the reaction rate constants significantly improves the nominal model prediction of the ignition delay time, whereas its influence on the range and profile of the frequency distribution is rather weak due to the intrinsic relationship among the reactions being broken in the reduced mechanism.
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| 4. |
- Chen, Zhi-Qiang, et al.
(författare)
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Leveraging breeding programs and genomic data in Norway spruce (Picea abies L. Karst) for GWAS analysis
- 2021
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Ingår i: Genome Biology. - : BioMed Central (BMC). - 1465-6906 .- 1474-760X. ; 22:1
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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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| 5. |
- Dai, Y. L., et al.
(författare)
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Asynchronous embryonic germ cell development leads to a heterogeneity of postnatal ovarian follicle activation and may influence the timing of puberty onset in mice
- 2022
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Ingår i: BMC Biology. - : Springer Science and Business Media LLC. - 1741-7007. ; 20:1
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Tidskriftsartikel (refereegranskat)abstract
- Background Ovarian follicles, which are the basic units of female reproduction, are composed of oocytes and surrounding somatic (pre) granulosa cells (GCs). A recent study revealed that signaling in somatic preGCs controlled the activation (initial recruitment) of follicles in the adult ovaries, but it is also known that there are two waves of follicle with age-related heterogeneity in their developmental dynamics in mammals. Although this heterogeneity was proposed to be crucial for female reproduction, our understanding of how it arises and its significance is still elusive. Results In the current study, by deleting the key secreted factor KIT ligand from preGCs and analyzing the follicle cell developmental dynamics, we revealed distinct patterns of activation and growth associated with the two waves of follicles in mouse ovary. Our results confirmed that activation of adult wave follicles is initiated by somatic preGCs and dependent on the KIT ligand. By contrast, activation of first wave follicles, which are awakened from germ cells before follicle formation, can occur in the absence of preGC-secreted KIT ligand in postnatal ovaries and appears to be oocyte-initiated. We also found that the asynchronous activity of phosphatidylinositol 3 kinases (PI3K) signaling and meiotic process in embryonic germ cells lead to the follicle heterogeneity in postnatal ovaries. In addition, we supplied evidence that the time sequence of embryonic germ cell development and its related first wave follicle growth are correlated to the time of puberty onset in females. Conclusion Taken together, our study provides evidence that asynchronous development of embryonic oocytes leads to the heterogeneity of postnatal ovarian follicle activation and development, and affects the timing of onset of puberty in females.
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| 6. |
- Kristan, Matej, et al.
(författare)
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The Ninth Visual Object Tracking VOT2021 Challenge Results
- 2021
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Ingår i: 2021 IEEE/CVF INTERNATIONAL CONFERENCE ON COMPUTER VISION WORKSHOPS (ICCVW 2021). - : IEEE COMPUTER SOC. - 9781665401913 ; , s. 2711-2738
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Konferensbidrag (refereegranskat)abstract
- The Visual Object Tracking challenge VOT2021 is the ninth annual tracker benchmarking activity organized by the VOT initiative. Results of 71 trackers are presented; many are state-of-the-art trackers published at major computer vision conferences or in journals in recent years. The VOT2021 challenge was composed of four sub-challenges focusing on different tracking domains: (i) VOT-ST2021 challenge focused on short-term tracking in RGB, (ii) VOT-RT2021 challenge focused on "real-time" short-term tracking in RGB, (iii) VOT-LT2021 focused on long-term tracking, namely coping with target disappearance and reappearance and (iv) VOT-RGBD2021 challenge focused on long-term tracking in RGB and depth imagery. The VOT-ST2021 dataset was refreshed, while VOT-RGBD2021 introduces a training dataset and sequestered dataset for winner identification. The source code for most of the trackers, the datasets, the evaluation kit and the results along with the source code for most trackers are publicly available at the challenge website(1).
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| 7. |
- Kristan, Matej, et al.
(författare)
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The Visual Object Tracking VOT2013 challenge results
- 2013
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Ingår i: 2013 IEEE INTERNATIONAL CONFERENCE ON COMPUTER VISION WORKSHOPS (ICCVW). - : IEEE. - 9781479930227 ; , s. 98-111
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Konferensbidrag (refereegranskat)abstract
- Visual tracking has attracted a significant attention in the last few decades. The recent surge in the number of publications on tracking-related problems have made it almost impossible to follow the developments in the field. One of the reasons is that there is a lack of commonly accepted annotated data-sets and standardized evaluation protocols that would allow objective comparison of different tracking methods. To address this issue, the Visual Object Tracking (VOT) workshop was organized in conjunction with ICCV2013. Researchers from academia as well as industry were invited to participate in the first VOT2013 challenge which aimed at single-object visual trackers that do not apply pre-learned models of object appearance (model-free). Presented here is the VOT2013 benchmark dataset for evaluation of single-object visual trackers as well as the results obtained by the trackers competing in the challenge. In contrast to related attempts in tracker benchmarking, the dataset is labeled per-frame by visual attributes that indicate occlusion, illumination change, motion change, size change and camera motion, offering a more systematic comparison of the trackers. Furthermore, we have designed an automated system for performing and evaluating the experiments. We present the evaluation protocol of the VOT2013 challenge and the results of a comparison of 27 trackers on the benchmark dataset. The dataset, the evaluation tools and the tracker rankings are publicly available from the challenge website(1).
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| 8. |
- Kristan, Matej, et al.
(författare)
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The Visual Object Tracking VOT2014 Challenge Results
- 2015
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Ingår i: COMPUTER VISION - ECCV 2014 WORKSHOPS, PT II. - Cham : Springer. - 9783319161808 - 9783319161815 ; , s. 191-217
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Konferensbidrag (refereegranskat)abstract
- The Visual Object Tracking challenge 2014, VOT2014, aims at comparing short-term single-object visual trackers that do not apply pre-learned models of object appearance. Results of 38 trackers are presented. The number of tested trackers makes VOT 2014 the largest benchmark on short-term tracking to date. For each participating tracker, a short description is provided in the appendix. Features of the VOT2014 challenge that go beyond its VOT2013 predecessor are introduced: (i) a new VOT2014 dataset with full annotation of targets by rotated bounding boxes and per-frame attribute, (ii) extensions of the VOT2013 evaluation methodology, (iii) a new unit for tracking speed assessment less dependent on the hardware and (iv) the VOT2014 evaluation toolkit that significantly speeds up execution of experiments. The dataset, the evaluation kit as well as the results are publicly available at the challenge website (http://votchallenge.net).
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| 9. |
- Li, Bo, et al.
(författare)
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Wind tunnel test study on influence of open/close operation on aerodynamic noise characteristics of high-speed pantographs
- 2024
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Ingår i: Zhongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Central South University (Science and Technology). - 1672-7207. ; 55:5, s. 1846-1854
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Tidskriftsartikel (refereegranskat)abstract
- Wind tunnel tests of aerodynamic noise at wind speeds from 160 km/h to 324 km/h were carried out for high speed pantograph developed by Beijing CRRC CED Co. Ltd. The effects of wind speed and open/close operation status on pantograph aerodynamic noise characteristics were analyzed, and the pantograph aerodynamic noise at higher speed was predicted. The results show that the aerodynamic noise of the pantograph and its propagation characteristics are closely related to the wind speed and operating status. The panhead and nearby areas are prone to single-tone noise due to the influence of shedding vortices. The total sound pressure energy of the far-field noise increases with the power of 5.6 − 6.0 of wind speed. The total sound pressure levels of the pantograph far-field noise in the open/closed state are predicted to be about 106.8 dB and 106.6 dB respectively at the wind speed of 400 km/h by data fitting.
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| 10. |
- Luo, Ziteng, et al.
(författare)
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Linking roots, preferential flow, and soil moisture redistribution in deciduous and coniferous forest soils
- 2022
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Ingår i: Journal of Soils and Sediments. - : Springer Science and Business Media LLC. - 1614-7480 .- 1439-0108.
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Tidskriftsartikel (refereegranskat)abstract
- Soil moisture (i.e., the changes in the gravimetric soil water content) redistribution is closely linked with root distribution and preferential flow in soils. This study aimed at exploring the soil water content distribution in the presence of root-enhanced preferential flow in deciduous (Quercus variabilis BI.) and coniferous forests (Platycladus orientalis (L.)).
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