| 1. |
- He, Yan, et al.
(författare)
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Discovering Optimal Triplets for Assessing the Uncertainties of Satellite-Derived Evapotranspiration Products
- 2023
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Ingår i: Remote Sensing. - 2072-4292. ; 15:13
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Tidskriftsartikel (refereegranskat)abstract
- Information relating to errors in evapotranspiration (ET) products, including satellite-derived ET products, is critical to their application but often challenging to obtain, with a limited number of flux towers available for the sufficient validation of measurements. Triple collocation (TC) methods can assess the inherent uncertainties of the above ET products using just three independent variables as a triplet input. However, both the severity with which the variables in the triplet violate the assumptions of zero error correlations and the corresponding impact on the error estimation are unknown. This study proposed a cross-correlation analysis approach to discover the optimal triplet of satellite-derived ET products with regard to providing the most reliable error estimation. All possible triple collocation solutions for the same product were first evaluated by the extended triple collocation (ETC), among which the optimum was selected based on the correlation between ETC-based and in-situ-based error metrics, and correspondingly, a statistic experiment based on ranked triplets demonstrated how the optimal triplet was valid for all pixels of the product. Six popular products (MOD16, PML_V2, GLASS, SSEBop, ERA5, and GLEAM) that were produced between 2003 to 2018 and which cover China’s mainland were chosen for the experiment, in which the error estimates were compared with measurements from 23 in-situ flux towers. The findings suggest that (1) there exists an optimal triplet in which a product as an input of TC with other collocating inputs together violate TC assumptions the least; (2) the error characteristics of the six ET products varied significantly across China, with GLASS performing the best (median error: 0.1 mm/day), followed by GLEAM, ERA5, and MOD16 (median errors below 0.2 mm/day), while PML_V2 and SSEBop had slightly higher median errors (0.24 mm/day and 0.27 mm/day, respectively); and (3) removing seasonal variations in ET signals has a substantial impact on enhancing the accuracy of error estimations.
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| 2. |
- Lu, Quanming, et al.
(författare)
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Features of separatrix regions in magnetic reconnection : Comparison of 2-D particle-in-cell simulations and Cluster observations
- 2010
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Ingår i: Journal of Geophysical Research. - 0148-0227 .- 2156-2202. ; 115:11
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Tidskriftsartikel (refereegranskat)abstract
- In collisionless magnetic reconnection, the in-plane Hall currents are carried mainly by the magnetized electrons. The in-plane Hall currents are directed toward the X line along the magnetic field lines just inside the separatrices and away from the X line along the separatrices. Such a current system leads to the quadrupole out-of-plane magnetic field with the peaks between the regions carrying the in-plane currents. Simultaneously, the electron flow toward the X line along the separatrices causes electron density depletions along the separatrices. In this paper, the features of separatrix regions in magnetic reconnection and the relations between the electron density depletions and the out-of-plane magnetic field are investigated with both two-dimensional particle-in-cell simulations and Cluster observations. We conclude that the electron density depletions are formed because of the magnetic mirror, and they are outside the peaks of the out-of-plane magnetic field. Such a theoretical prediction is confirmed by both simulations and observations.
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| 3. |
- Gumz, Michelle L, et al.
(författare)
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Toward Precision Medicine : Circadian Rhythm of Blood Pressure and Chronotherapy for Hypertension - 2021 NHLBI Workshop Report
- 2023
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Ingår i: Hypertension. - : Wolters Kluwer. - 0194-911X .- 1524-4563. ; 80:3, s. 503-522
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Tidskriftsartikel (refereegranskat)abstract
- Healthy individuals exhibit blood pressure variation over a 24-hour period with higher blood pressure during wakefulness and lower blood pressure during sleep. Loss or disruption of the blood pressure circadian rhythm has been linked to adverse health outcomes, for example, cardiovascular disease, dementia, and chronic kidney disease. However, the current diagnostic and therapeutic approaches lack sufficient attention to the circadian rhythmicity of blood pressure. Sleep patterns, hormone release, eating habits, digestion, body temperature, renal and cardiovascular function, and other important host functions as well as gut microbiota exhibit circadian rhythms, and influence circadian rhythms of blood pressure. Potential benefits of nonpharmacologic interventions such as meal timing, and pharmacologic chronotherapeutic interventions, such as the bedtime administration of antihypertensive medications, have recently been suggested in some studies. However, the mechanisms underlying circadian rhythm-mediated blood pressure regulation and the efficacy of chronotherapy in hypertension remain unclear. This review summarizes the results of the National Heart, Lung, and Blood Institute workshop convened on October 27 to 29, 2021 to assess knowledge gaps and research opportunities in the study of circadian rhythm of blood pressure and chronotherapy for hypertension.
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| 4. |
- Ren, Weicheng, et al.
(författare)
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Genetic and transcriptomic analyses of diffuse large B-cell lymphoma patients with poor outcomes within two years of diagnosis
- 2024
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Ingår i: Leukemia. - : Springer Nature. - 0887-6924 .- 1476-5551. ; 38:2, s. 438-441
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Tidskriftsartikel (refereegranskat)abstract
- Despite the improvements in clinical outcomes for DLBCL, a significant proportion of patients still face challenges with refractory/relapsed (R/R) disease after receiving first-line R-CHOP treatment. To further elucidate the underlying mechanism of R/R disease and to develop methods for identifying patients at risk of early disease progression, we integrated clinical, genetic and transcriptomic data derived from 2805 R-CHOP-treated patients from seven independent cohorts. Among these, 887 patients exhibited R/R disease within two years (poor outcome), and 1918 patients remained in remission at two years (good outcome). Our analysis identified four preferentially mutated genes (TP53, MYD88, SPEN, MYC) in the untreated (diagnostic) tumor samples from patients with poor outcomes. Furthermore, transcriptomic analysis revealed a distinct gene expression pattern linked to poor outcomes, affecting pathways involved in cell adhesion/migration, T-cell activation/regulation, PI3K, and NF-kappa B signaling. Moreover, we developed and validated a 24-gene expression score as an independent prognostic predictor for treatment outcomes. This score also demonstrated efficacy in further stratifying high-risk patients when integrated with existing genetic or cell-of-origin subtypes, including the unclassified cases in these models. Finally, based on these findings, we developed an online analysis tool (https://lymphprog.serve.scilifelab.se/app/lymphprog) that can be used for prognostic prediction for DLBCL patients.
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| 5. |
- Shah, Suraj, et al.
(författare)
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Evaluating the added value of multi-variable calibration of SWAT with remotely sensed evapotranspiration data for improving hydrological modeling
- 2021
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Ingår i: Journal of Hydrology. - : Elsevier BV. - 0022-1694. ; 603
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Tidskriftsartikel (refereegranskat)abstract
- Hydrological processes in a watershed consist of multiple sub-processes (such as plant growth, evapotranspiration, water yield, and soil–water balance) that have complex interactions. The common practice of calibrating hydrological models against only a single variable (e.g., streamflow) can lead to parameter uncertainty (also known as equifinality), resulting in significant uncertainties in the representation and simulation of sub-processes. As multi-variable calibration can be a potential solution to this issue, we tested the integration of spatially and temporally gridded remotely sensed evapotranspiration (RS-ET) data with the Soil and Water Assessment Tool (SWAT) hydrological model. This approach was intended to reduce equifinality by enhancing related hydrological sub-processes in both space and time rather than improving the evaluation metrics at the streamflow outlet. We further introduced the principle of repeated measure design in the calibration process, where the SWAT was calibrated under two different schemes: Scheme1 (using only streamflow data) and Scheme2 (using both RS-ET and streamflow data). The model's performance was evaluated using the concept of stability at multiple spatial scales (basin outlet, sub-basins, and hydrological response units) and aspects (different model outputs and most sensitive calibrated parameters). The significance of the difference between the stabilities produced by the two schemes was estimated using the Mann–Whitney U test. Testing this approach in Meichuan Basin (China) showed that Scheme2 substantially reduced equifinality for calibrated parameters and model outputs compared to Scheme1. In addition, the model solutions and outputs for Scheme2 were significantly different from Scheme1. Our results demonstrate the added value of using increasingly available open-access RS-ET data for improving hydrological model calibration.
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| 6. |
- Song, B. Q., et al.
(författare)
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Construction of A-B heterolayer intermetallic crystals : Case studies of the 1144-phase TM-phosphides AB(TM)(4)P-4 (TM=Fe, Ru, Co, Ni)
- 2021
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Ingår i: Physical Review Materials. - : American Physical Society. - 2475-9953. ; 5:9
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Tidskriftsartikel (refereegranskat)abstract
- The discovery of the 1144 phase, e.g., CaKFe4As4, creates opportunities to build novel intermetallics with alternative stacking of two parent compounds. Here we formalize the idea by defining a class of bulk crystalline solids with A-B stacking (including 1144 phases and beyond), which is a generalization of heterostructures from few-layer or thin-film semiconductors to bulk intermetallics. Theoretically, four families of phosphides AB(TM)(4)P-4 (TM=Fe, Ru, Co, Ni) are investigated by first-principles calculations, wherein configurational, vibrational, and electronic degrees of freedom are considered. It predicts a variety of stable 1144 phases (especially Ru- and Fe-phosphides). Stability rules are found and structural/electronic properties are discussed. Experimentally, we synthesize high-purity CaKRu4P4 as a proof of principle example. The synthetic method is simple and easily applied. Moreover, it alludes to a strategy to explore complex multicomponent compounds, facilitated by a phase diagram coordinated by collective descriptors.
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| 7. |
- Wang, Rongsheng, et al.
(författare)
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Observation of double layer in the separatrix region during magnetic reconnection
- 2014
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Ingår i: Geophysical Research Letters. - 0094-8276 .- 1944-8007. ; 41:14, s. 4851-4858
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Tidskriftsartikel (refereegranskat)abstract
- We present in situ observation of double layer (DL) and associated electron measurement in the subspin time resolution in the separatrix region during reconnection for the first time. The DL is inferred to propagate away from the X line at a velocity of about ion acoustic speed and the parallel electric field carried by the DL can reach -20 mV/m. The electron displays a beam distribution inside the DL and streams toward the X line with a local electron Alfven velocity. A series of electron holes moving toward the X line are observed in the wake of the DL. The identification of multiple similar DLs indicates that they are persistently produced and therefore might play an important role in energy conversion during reconnection. The observation suggests that energy dissipation during reconnection can occur in any region where the DL can reach.
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| 8. |
- Xiong, Jiang, et al.
(författare)
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Collocated Electric and Magnetic Dipoles With Extremely Low Correlation as a Reference Antenna for Polarization Diversity MIMO Applications
- 2012
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Ingår i: IEEE Antennas and Wireless Propagation Letters. - 1536-1225 .- 1548-5757. ; 11, s. 423-426
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Tidskriftsartikel (refereegranskat)abstract
- In this letter, a magnetic dipole (M-dipole) and an electric dipole (E-dipole) are designed to form a collocated polarization-diversity-based dual-antenna system. The M-dipole is a modified shielded loop with multiple feed, and the E-dipole is a traditional lambda/2 dipole. Measured results show that both radiators have ideal impedance matching and port isolation and identical omnidirectional pattern with perfect orthogonal polarization at 860 MHz. The upper bound of the envelope correlation coefficient rho(emax), with the measured antenna efficiency taken into account, is only 0.018, and it is the lowest value when compared to some previous publications. Excellent effective diversity gain and channel capacity are also achieved at the operating frequency. The proposed dual-antenna system can mainly be used as a reference antenna for evaluating the performance of future collocated polarization-diversity-based multiple-input-multiple-output (MIMO) antennas.
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