| 1. |
- Wang, X. J., et al.
(author)
-
Contrasting characteristics, changes, and linkages of permafrost between the Arctic and the Third Pole
- 2022
-
In: Earth-Science Reviews. - : Elsevier BV. - 0012-8252. ; 230
-
Journal article (peer-reviewed)abstract
- Permafrost degradation poses serious threats to both natural and human systems through its influence on ecological-hydrological processes, infrastructure stability, and the climate system. The Arctic and the Third Pole (Tibetan Plateau, TP hereafter) are the two northern regions on Earth with the most extensive permafrost areas. However, there is a lack of systematic comparisons of permafrost characteristics and its climate and ecoenvironment between these two regions and their susceptibility to disturbances. This study provides a comprehensive review of the climate, ecosystem characteristics, ground temperature, permafrost extent, and active-layer thickness, as well as the past and future changes in permafrost in the Arctic and the TP. The potential consequences associated with permafrost degradation are also examined. Lastly, possible connections between the two regions through land-ocean-atmosphere interactions are explored. Both regions have experienced dramatic warming in recent decades, characterized by Arctic amplification and elevation-dependent warming on the TP. Permafrost temperatures have increased more rapidly in the Arctic than on the TP, and will likely be reinforced under a future high emission scenario. Near-surface permafrost extents are projected to shrink in both regions in the coming decades, with a more dramatic decline in the TP. The active layer on the TP is thicker and has substantially deepened, and is projected to thicken more than in the Arctic. Widespread permafrost degradation increases geohazard risk and has already wielded considerable effects on the human and natural systems. Permafrost changes have also exerted a pronounced impact on the climate system through changes in permafrost carbon and land-atmosphere interactions. Future research should involve comparative studies of permafrost dynamics in both regions that integrate long-term observations, high-resolution satellite measurements, and advanced Earth System models, with emphasis on linkages between the two regions.
|
|
| 2. |
- Cai, Y.-Z., et al.
(author)
-
Intermediate-luminosity red transients : Spectrophotometric properties and connection to electron-capture supernova explosions
- 2021
-
In: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 654
-
Journal article (peer-reviewed)abstract
- We present the spectroscopic and photometric study of five intermediate-luminosity red transients (ILRTs), namely AT 2010dn, AT 2012jc, AT 2013la, AT 2013lb, and AT 2018aes. They share common observational properties and belong to a family of objects similar to the prototypical ILRT SN 2008S. These events have a rise time that is less than 15 days and absolute peak magnitudes of between −11.5 and −14.5 mag. Their pseudo-bolometric light curves peak in the range 0.5–9.0 × 1040 erg s−1 and their total radiated energies are on the order of (0.3–3) × 1047 erg. After maximum brightness, the light curves show a monotonic decline or a plateau, resembling those of faint supernovae IIL or IIP, respectively. At late phases, the light curves flatten, roughly following the slope of the 56Co decay. If the late-time power source is indeed radioactive decay, these transients produce 56Ni masses on the order of 10−4 to 10−3 M⊙. The spectral energy distribution of our ILRT sample, extending from the optical to the mid-infrared (MIR) domain, reveals a clear IR excess soon after explosion and non-negligible MIR emission at very late phases. The spectra show prominent H lines in emission with a typical velocity of a few hundred km s−1, along with Ca II features. In particular, the [Ca II] λ7291,7324 doublet is visible at all times, which is a characteristic feature for this family of transients. The identified progenitor of SN 2008S, which is luminous in archival Spitzer MIR images, suggests an intermediate-mass precursor star embedded in a dusty cocoon. We propose the explosion of a super-asymptotic giant branch star forming an electron-capture supernova as a plausible explanation for these events.
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
- Hua, Y., et al.
(author)
-
Molecular characteristics of eae-positive clinical Shiga toxin-producing Escherichia coli in Sweden
- 2020
-
In: Emerging microbes & infections. - : Informa UK Limited. - 2222-1751. ; 9:1, s. 2562-2570
-
Journal article (peer-reviewed)abstract
- Shiga toxin (Stx)-producing Escherichia coli (STEC) can cause a wide range of symptoms from asymptomatic carriage, mild diarrhea to bloody diarrhea (BD) and hemolytic uremic syndrome (HUS). Intimin, encoded by the eae gene, also plays a critical role in STEC pathogenesis. Herein, we investigated the prevalence and genetic diversity of eae among clinical STEC isolates from patients with diarrhea, BD, HUS as well as from asymptomatic STEC-positive individuals in Sweden with whole-genome sequencing. We found that 173 out of 239 (72.4%) of clinical STEC strains were eae positive. Six eae subtypes (epsilon 1, gamma 1, beta 3, theta, zeta and rho) were identified eae and its subtype gamma 1 were significantly overrepresented in O157:H7 strains isolated from BD and HUS patients. epsilon 1 was associated with O121:H19 and O103:H2 strains, and beta 3 to O26:H11 strains. The combination of eae subtype gamma 1 and stx subtype (stx (2) or stx (1)+stx (2)) is more likely to cause severe disease, suggesting the possibility of using eae genotypes in risk assessment of STEC infection. In summary, this study demonstrated a high prevalence of eae in clinical STEC strains and considerable genetic diversity of eae in STEC strains in Sweden from 1994 through 2018, and revealed association between eae subtypes and disease severity.
|
|
| 7. |
- Wan, X., et al.
(author)
-
Efficient and stable planar all-inorganic perovskite solar cells based on high-quality CsPbBr3 films with controllable morphology
- 2020
-
In: Journal of Energy Challenges and Mechanics. - : Elsevier. - 2056-9386. ; 46, s. 8-15
-
Journal article (peer-reviewed)abstract
- All-inorganic cesium lead bromide (CsPbBr3) perovskite is attracting growing interest as functional materials in photovoltaics and other optoelectronic devices due to its superb stability. However, the fabrication of high-quality CsPbBr3 films still remains a big challenge by solution-process because of the low solubility of the cesium precursor in common solvents. Herein, we report a facile solution-processed approach to prepare high-quality CsPbBr3 perovskite films via a two-step spin-coating method, in which the CsBr methanol/H2O mixed solvent solution is spin-coated onto the lead bromide films, followed by an isopropanol-assisted post-treatment to regulate the crystallization process and to control the film morphology. In this fashion, dense and uniform CsPbBr3 films are obtained consisting of large crystalline domains with sizes up to microns and low defect density. The effectiveness of the resulting CsPbBr3 films is further examined in perovskite solar cells (PSCs) with a simplified planar architecture of fluorine‒doped tin oxide/compact TiO2/CsPbBr3/carbon, which deliver a maximum power conversion efficiency of 8.11% together with excellent thermal and humidity stability. The present work offers a simple and effective strategy in fabrication of high-quality CsPbBr3 films for efficient and stable PSCs as well as other optoelectronic devices.
|
|
| 8. |
- Yao, Zhaoyang, et al.
(author)
-
Pyrene-Based Dopant-Free Hole-Transport Polymers with Fluorine-Induced Favorable Molecular Stacking Enable Efficient Perovskite Solar Cells
- 2022
-
In: Angewandte Chemie International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 61:24
-
Journal article (peer-reviewed)abstract
- A new class of polymeric hole-transport materials (HTMs) are explored by inserting a two-dimensionally conjugated fluoro-substituted pyrene into thiophene and selenophene polymeric chains. The broad conjugated plane of pyrene and “Lewis soft” selenium atoms not only enhance the π–π stacking of HTM molecules greatly but also render a strong interaction with the perovskite surface, leading to an efficient charge transport/transfer in both the HTM layer and the perovskite/HTM interface. Note that fluorine substitution adjacent to pyrene boosts the stacking of HTMs towards a more favorable face-on orientation, further facilitating the efficient charge transport. As a result, perovskite solar cells (PSCs) employing PE10 as dopant-free HTM afford an excellent efficiency of 22.3 % and the dramatically enhanced device longevity, qualifying it among the best PSCs based on dopant-free HTMs.
|
|
| 9. |
|
|
| 10. |
- Abe, K., et al.
(author)
-
Neutron tagging following atmospheric neutrino events in a water Cherenkov detector
- 2022
-
In: Journal of Instrumentation. - : Institute of Physics (IOP). - 1748-0221. ; 17:10
-
Journal article (peer-reviewed)abstract
- We present the development of neutron-tagging techniques in Super-Kamiokande IV using a neural network analysis. The detection efficiency of neutron capture on hydrogen is estimated to be 26%, with a mis-tag rate of 0.016 per neutrino event. The uncertainty of the tagging efficiency is estimated to be 9.0%. Measurement of the tagging efficiency with data from an Americium-Beryllium calibration agrees with this value within 10%. The tagging procedure was performed on 3,244.4 days of SK-IV atmospheric neutrino data, identifying 18,091 neutrons in 26,473 neutrino events. The fitted neutron capture lifetime was measured as 218 +/- 9 mu s.
|
|
| 11. |
- Ackley, K., et al.
(author)
-
Observational constraints on the optical and near-infrared emission from the neutron star-black hole binary merger candidate S190814bv
- 2020
-
In: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 643
-
Journal article (peer-reviewed)abstract
- Context. Gravitational wave (GW) astronomy has rapidly reached maturity, becoming a fundamental observing window for modern astrophysics. The coalescences of a few tens of black hole (BH) binaries have been detected, while the number of events possibly including a neutron star (NS) is still limited to a few. On 2019 August 14, the LIGO and Virgo interferometers detected a high-significance event labelled S190814bv. A preliminary analysis of the GW data suggests that the event was likely due to the merger of a compact binary system formed by a BH and a NS.Aims. In this paper, we present our extensive search campaign aimed at uncovering the potential optical and near infrared electromagnetic counterpart of S190814bv. We found no convincing electromagnetic counterpart in our data. We therefore use our non-detection to place limits on the properties of the putative outflows that could have been produced by the binary during and after the merger.Methods. Thanks to the three-detector observation of S190814bv, and given the characteristics of the signal, the LIGO and Virgo Collaborations delivered a relatively narrow localisation in low latency - a 50% (90%) credible area of 5 deg(2) (23 deg(2)) - despite the relatively large distance of 26752 Mpc. ElectromagNetic counterparts of GRAvitational wave sources at the VEry Large Telescope collaboration members carried out an intensive multi-epoch, multi-instrument observational campaign to identify the possible optical and near infrared counterpart of the event. In addition, the ATLAS, GOTO, GRAWITA-VST, Pan-STARRS, and VINROUGE projects also carried out a search on this event. In this paper, we describe the combined observational campaign of these groups.Results. Our observations allow us to place limits on the presence of any counterpart and discuss the implications for the kilonova (KN), which was possibly generated by this NS-BH merger, and for the strategy of future searches. The typical depth of our wide-field observations, which cover most of the projected sky localisation probability (up to 99.8%, depending on the night and filter considered), is r similar to 22 (resp. K similar to 21) in the optical (resp. near infrared). We reach deeper limits in a subset of our galaxy-targeted observations, which cover a total similar to 50% of the galaxy-mass-weighted localisation probability. Altogether, our observations allow us to exclude a KN with large ejecta mass M greater than or similar to 0.1 M-circle dot to a high (> 90%) confidence, and we can exclude much smaller masses in a sub-sample of our observations. This disfavours the tidal disruption of the neutron star during the merger.Conclusions. Despite the sensitive instruments involved in the campaign, given the distance of S190814bv, we could not reach sufficiently deep limits to constrain a KN comparable in luminosity to AT 2017gfo on a large fraction of the localisation probability. This suggests that future (likely common) events at a few hundred megaparsecs will be detected only by large facilities with both a high sensitivity and large field of view. Galaxy-targeted observations can reach the needed depth over a relevant portion of the localisation probability with a smaller investment of resources, but the number of galaxies to be targeted in order to get a fairly complete coverage is large, even in the case of a localisation as good as that of this event.
|
|
| 12. |
|
|
| 13. |
- Chen, Z. H., et al.
(author)
-
The Hydrogen-poor Superluminous Supernovae from the Zwicky Transient Facility Phase I Survey. I. Light Curves and Measurements
- 2023
-
In: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 943:1
-
Journal article (peer-reviewed)abstract
- During the Zwicky Transient Facility (ZTF) Phase I operations, 78 hydrogen-poor superluminous supernovae (SLSNe-I) were discovered in less than 3 yr, constituting the largest sample from a single survey. This paper (Paper I) presents the data, including the optical/UV light curves and classification spectra, while Paper II in this series will focus on the detailed analysis of the light curves and modeling. Our photometry is primarily taken by ZTF in the g, r, and i bands, and with additional data from other ground-based facilities and Swift. The events of our sample cover a redshift range of z = 0.06 − 0.67, with a median and 1σ error (16% and 84% percentiles) of zmed=0.265. The peak luminosity covers −22.8 mag ≤ Mg,peak ≤ −19.8 mag, with a median value of -21.48. The light curves evolve slowly with a mean rest-frame rise time of trise = 41.9 ± 17.8 days. The luminosity and timescale distributions suggest that low-luminosity SLSNe-I with a peak luminosity ∼−20 mag or extremely fast-rising events (<10 days) exist, but are rare. We confirm previous findings that slowly rising SLSNe-I also tend to fade slowly. The rest-frame color and temperature evolution show large scatters, suggesting that the SLSN-I population may have diverse spectral energy distributions. The peak rest-frame color shows a moderate correlation with the peak absolute magnitude, i.e., brighter SLSNe-I tend to have bluer colors. With optical and UV photometry, we construct the bolometric luminosity and derive a bolometric correction relation that is generally applicable for converting g, r-band photometry to the bolometric luminosity for SLSNe-I.
|
|
| 14. |
- Chen, Z. H., et al.
(author)
-
The Hydrogen-poor Superluminous Supernovae from the Zwicky Transient Facility Phase I Survey. II. Light-curve Modeling and Characterization of Undulations
- 2023
-
In: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 943:1, s. 42-
-
Journal article (peer-reviewed)abstract
- We present analysis of the light curves (LCs) of 77 hydrogen-poor superluminous supernovae (SLSNe I) discovered during the Zwicky Transient Facility Phase I operation. We find that the majority (67%) of the sample can be fit equally well by both magnetar and ejecta-circumstellar medium (CSM) interaction plus 56Ni decay models. This implies that LCs alone cannot unambiguously constrain the physical power sources for an SLSN I. However, 23% of the sample show inverted V-shape, steep-declining LCs or features of long rise and fast post-peak decay, which are better described by the CSM+Ni model. The remaining 10% of the sample favors the magnetar model. Moreover, our analysis shows that the LC undulations are quite common, with a fraction of 18%-44% in our gold sample. Among those strongly undulating events, about 62% of them are found to be CSM-favored, implying that the undulations tend to occur in the CSM-favored events. Undulations show a wide range in energy and duration, with median values (and 1σ errors) being as 1.7 % − 0.7 % + 1.5 % E rad , total and 28.8 − 9.1 + 14.4 days, respectively. Our analysis of the undulation timescales suggests that intrinsic temporal variations of the central engine can explain half of the undulating events, while CSM interaction (CSI) can account for the majority of the sample. Finally, all of the well-observed He-rich SLSNe Ib either have strongly undulating LCs or the LCs are much better fit by the CSM+Ni model. These observations imply that their progenitor stars have not had enough time to lose all of the He-envelopes before supernova explosions, and H-poor CSM are likely to present in these events.
|
|
| 15. |
|
|
| 16. |
|
|
| 17. |
|
|
| 18. |
|
|
| 19. |
|
|
| 20. |
|
|
| 21. |
|
|
| 22. |
|
|
| 23. |
- Ha, S., et al.
(author)
-
Transmission of low-energy Cl- ions through Al2O3 insulating nanocapillaries
- 2020
-
In: Acta Physica Sinica. - : Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences. - 1000-3290. ; 69:9
-
Journal article (peer-reviewed)abstract
- The transmission of 10-keV Cl- ions through Al2O3 insulating nanocapillaries is studied both by experiment and simulation. The double-peak structure in the transmitted angular distribution is found to be the same as our previous result. The peak around the direction of the primary beam is caused mainly by the directly transmitted Cl-, and the other peak around the tilt angle of Al2O3 nanocapillaries is mainly induced by Cl+ and Cl-0. The intensity of transmitted Cl- decreases with the tilt angle increasing, which is in accord with the geometrically allowed transmission. Beyond the geometrically allowed angle, the transmitted projectiles are mainly Cl+ ions and Cl-0 atoms. The ratio of transmitted Cl+ ion to Cl-0 atom drops as tilt angle increases, and it turns more obvious when the tilt angle is larger than the limit of the geometrical transmission. A detailed physics process was developed within Geometry and Tracking 4 (Geant4) to perform the trajectory simulation, in which the forces from the deposited charges and the image charges, the scattering from the surfaces as well as the charge exchange are taken into consideration. The transmissions at the tilt angle of 1.6 degrees are simulated for the cases without and with deposited charges of -100 e/capillary. For the deposition charge quantity of -100 e/capillary, the majority of the transmitted projectiles are mainly the directly transmitted Cl- ions exiting to the direction of tilt angle, and the transmitted Cl-0 and Cl+ account for a very small portion. While for the case with no deposited charges, the simulation results agree well with the experimental results. The dependence of the scattering process on the tilt angle, which results in the different features in the transmitted projectiles, is studied in detail by the simulation. It is found that the transmitted Cl-0 atoms exit through single to multiple scattering, and most of transmitted Cl-0 atoms exit through single and double scattering, and are centered along the axis of nanocapillaries, while Cl+ ions mainly exit by single scattering, which results in the fact that the intensity of the transmitted Cl-0 atoms drops slower than that of the transmitted Cl+ ions with the increase of the tilt angle, leading the ratio of the transmitted Cl+ to Cl-0 to decrease as the tilt angle increases in experiment. Our results describe the physical mechanism of low-energy ions through insulating nanocapillaries in detail, i.e. how the scattering process dominates the final transmission. It is found that the transmission of the negative ions in the energy range above 10 keV is caused by the scattering and the charge exchange process.
|
|
| 24. |
- Hua, Y., et al.
(author)
-
Molecular Characterization of the Enterohemolysin Gene (ehxA) in Clinical Shiga Toxin-Producing Escherichia coli Isolates
- 2021
-
In: Toxins. - : MDPI AG. - 2072-6651. ; 13:1
-
Journal article (peer-reviewed)abstract
- Shiga toxin (Stx)-producing Escherichia coli (STEC) is an important foodborne pathogen with the ability to cause bloody diarrhea (BD) and hemolytic uremic syndrome (HUS). Little is known about enterohemolysin-encoded by ehxA. Here we investigated the prevalence and diversity of ehxA in 239 STEC isolates from human clinical samples. In total, 199 out of 239 isolates (83.26%) were ehxA positive, and ehxA was significantly overrepresented in isolates carrying stx(2a) + stx(2c) (p < 0.001) and eae (p < 0.001). The presence of ehxA was significantly associated with BD and serotype O157:H7. Five ehxA subtypes were identified, among which, ehxA subtypes B, C, and F were overrepresented in eae-positive isolates. All O157:H7 isolates carried ehxA subtype B, which was related to BD and HUS. Three ehxA groups were observed in the phylogenetic analysis, namely, group ? (ehxA subtype A), group II (ehxA subtype B, C, and F), and group (ehxA subtype D). Most BD- and HUS-associated isolates were clustered into ehxA group II, while ehxA group ? was associated with non-bloody stool and individuals >= 10 years of age. The presence of ehxA + eae and ehxA + eae + stx(2) was significantly associated with HUS and O157:H7 isolates. In summary, this study showed a high prevalence and the considerable genetic diversity of ehxA among clinical STEC isolates. The ehxA genotypes (subtype B and phylogenetic group II) could be used as risk predictors, as they were associated with severe clinical symptoms, such as BD and HUS. Furthermore, ehxA, together with stx and eae, can be used as a risk predictor for HUS in STEC infections.
|
|
| 25. |
- Hua, Y., et al.
(author)
-
Whole-genome characterization of hemolytic uremic syndrome-causing Shiga toxin-producing Escherichia coli in Sweden
- 2021
-
In: Virulence. - : Informa UK Limited. - 2150-5594 .- 2150-5608. ; 12:1, s. 1296-1305
-
Journal article (peer-reviewed)abstract
- Shiga toxin-producing Escherichia coli, a foodborne bacterial pathogen, has been linked to a broad spectrum of clinical outcomes ranging from asymptomatic carriage to fatal hemolytic uremic syndrome (HUS). Here, we collected clinical data and STEC strains from HUS patients from 1994 through 2018, whole-genome sequencing was performed to molecularly characterize HUS-associated STEC strains, statistical analysis was conducted to identify bacterial genetic factors associated with severe outcomes in HUS patients. O157:H7 was the most predominant serotype (57%) among 54 HUS-associated STEC strains, followed by O121:H19 (19%) and O26:H11 (7%). Notably, some non-predominant serotypes such as O59:H17 (2%) and O109:H21 (2%) also caused HUS. All O157:H7 strains with one exception belonged to clade 8. During follow-up at a median of 4years, 41% of the patients had renal sequelae. Fifty-nine virulence genes were found to be statistically associated with severe renal sequelae, these genes encoded type II and type III secretion system effectors, chaperones, and other factors. Notably, virulence genes associated with severe clinical outcomes were significantly more prevalent in O157:H7 strains. In contrast, genes related to mild symptoms were evenly distributed across all serotypes. The whole-genome phylogeny indicated high genomic diversity among HUS-STEC strains. No distinct cluster was found between HUS and non-HUS STEC strains. The current study showed that O157:H7 remains the main cause of STEC-associated HUS, despite the rising importance of other non-O157 serotypes. Besides, O157:H7 is associated with severe renal sequelae in the follow-up, which could be a risk factor for long-term prognosis in HUS patients. © 2021 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
|
|
| 26. |
- Kim, I., et al.
(author)
-
Plurisubharmonicity and Geodesic Convexity of Energy Function on Teichmuller Space
- 2022
-
In: Indiana University Mathematics Journal. - : Indiana University Mathematics Journal. - 0022-2518. ; 71:1, s. 1-36
-
Journal article (peer-reviewed)abstract
- Let pi : X -> T be Teichmuller curve over Teichmuller space T, such that the fiber X-z = pi(-1) (z) is exactly the Riemann surface given by the complex structure z is an element of T. For a fixed Riemannian manifold M and a continuous map u(0): M -> X-z0, let E(z) denote the energy function of the harmonic map u(z) : M -> X-z homotopic to u(0), z is an element of T. We obtain the first and the second variations of the energy function E(z), and show that logE(z) is strictly plurisubharmonic on Teichmuller space, and that both E(z) and logE(z) are plurisubharmonic exhausting functions. We also obtain a precise formula on the second variation of E- (1/2) if dim M = 1. In particular, we get the formula of Axelsson-Schumacher on the second variation of the geodesic length function. We give also a simple and corrected proof for the theorem of Yamada, the convexity of energy function E(t) along Weil-Petersson geodesics. As an application we show that E(t)(c) is also strictly convex for c > 5/6 and convex for c = 5/6 along Weil-Petersson geodesics. We also re-prove a Kerckhoff's theorem, which is a positive answer to the Nielsen realization problem.
|
|
| 27. |
- Li, P. F., et al.
(author)
-
Dynamics of low energy electrons transmitting throughstraight glass capillary: Tilt angle dependence br
- 2022
-
In: Acta Physica Sinica. - : Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences. - 1000-3290. ; 71:8
-
Journal article (peer-reviewed)abstract
- It is a hot topic that using glass capillary to focus and shape the charged particle beam, for it isinexpensive and simple. There are the cases that single glass capillaries are used to make the microbeam of thepositive ions. When it comes to electrons, their transmitting through insulating capillaries is complex and theattempt to use the glass capillary to produce electron beams in the size of micrometer needs further exploring.In this paper, the charging-up process of the 900-eV electrons transmitting through a glass capillary withthe grounded conductive-coated outer surface is reported. Two-dimensional angular distributions of thetransmitted electrons and their time evolutions are measured for the cases of various tilt angles of glass tube. Itis found that there are a considerable number of transmitted electrons at the tilt angle exceeding thegeometrical opening angle (1 degrees) of the glass tube. The intensity of transmitted electrons for large tilt angle (i.e. -1.15 degrees)can be considered as first falling to zero, then keeping zero for a long time, finally rising to a certain stablevalue. Correspondingly, the angular distribution center experiences moving towards negative-positive-negative-settled. The energy losses are measured for various tilt angles. The larger the tilt angles, the larger the energyloss of transmitted electrons is. To better understand the physics behind the observed phenomena, thesimulations of the energy loss for transmitted electrons at various tilt angles are performed by the Monte Carlomethod. The comparation between the simulated energy losses and the measured energy losses shows that theexperimental results are well explained by multiple deflections from the wall.
|
|
| 28. |
- Li, P. F., et al.
(author)
-
Stable transmission of low energy electrons in glass tube with outer surface grounded conductively shielding
- 2022
-
In: Acta Physica Sinica. - : Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences. - 1000-3290. ; 71:7
-
Journal article (peer-reviewed)abstract
- The electron microbeam is useful for modifying certain fragments of biomolecule. It is successful to applythe guiding effect to making the microbeam of positively charged particles by using single glass capillary.However, the mechanism for the electron transport through insulating capillaries is unclear. Meanwhile,previous researches show that there are oscillations of the transmission intensity of electrons with time in theglass capillaries with outer serface having no grounded conductive shielding, So, the application of glasscapillary to making the microbeam of electrons is limited. In this paper, the transmission of 1.5 and 0.9 keV electrons through the glass capillary without/with thegrounded conductive-coated outer surface are investigated, respectively. This study aims to understand themechanism for low energy electron transport in the glass capillaries, and find the conditions for the steadytransport of the electrons. Two-dimensional angular distribution of the transported electrons and its timeevolution are measured. It is found that the intensity of the transported electrons with the incident energythrough the glass capillaries for the glass capillaries without and with the grounded conductive-coated outersurface show the typical geometrical transmission characteristics. The time evolution of the 1.5- keV electrontransport presents an extremely complex variation for the glass capillary without the grounded conductive-coated outer surface. The intensity first falls, then rises and finally oscillates around a certain mean value.Correspondingly, the angular distribution center experiences moving towards positive-negative-settlement. Incomparison, the charge-up process of the 0.9 keV electron transport through the glass capillary with thegrounded conductive-coated outer surface shows a relatively simple behavior. At first, the intensity declines rapidly with time. Then, it slowly rises till a certain value and stays steady subsequently. The angulardistribution of transported electrons follows the intensity distribution in general, but with some delay. It quicklymoves to negative direction then comes back to positive direction. Finally, it regresses extremely slowly andends up around the tilt angle. To better understand the physics behind the observed phenomena, the simulationfor the interaction of the electrons with SiO2 material is performed to obtain the possible deposited chargedistribution by the CASINO code. Based on the analysis of the experimental results and the simulated chargedeposition, the conditions for stabilizing the electron transport through glass capillary arepresented.
|
|
| 29. |
- Mi, JR, et al.
(author)
-
Mendelian randomization in blood metabolites identifies triglycerides and fatty acids saturation level as associated traits linked to pancreatitis risk
- 2022
-
In: Frontiers in nutrition. - : Frontiers Media SA. - 2296-861X. ; 9, s. 1021942-
-
Journal article (peer-reviewed)abstract
- There is very limited evidence on the causal effects of blood metabolites on pancreatitis risks. To reveal the causal associations between plasma metabolites and pancreatitis risks, we performed two-sample Mendelian randomization (MR) and Bayesian model averaging (MR-BMA) analyses in European ancestry.MethodsThe summary-level statistics from two genome-wide association studies with 249 and 123 metabolic traits derived from two separate cohorts involving ~115,000 (UK Biobank) and ~25,000 individuals from European ancestry were used for the analyses. The summary statistics of four pancreatitis datasets from FinnGen R5 and two pancreatitis datasets from UK Biobank were exploited as the outcome. We first performed univariable MR analysis with different metabolic GWAS data on multiple pancreatitis datasets to demonstrate the association pattern among different metabolites categories. Next, we exploited the MR-BMA method to pinpoint the dominating factors on the increased risk of pancreatitis.ResultsIn the primary analysis with 249 traits, we found that plasma triglycerides were positively associated with pancreatitis risk. Intriguingly, a large number of traits associated with saturation or unsaturation of fatty acids also demonstrated causal associations. The replication study analyzing 123 metabolic traits suggested that bisallylic groups levels and omega-3 fatty acids were inversely correlated with pancreatitis risk. MR-BMA analyses indicated that the ratio of triglycerides to total lipid in various HDL particles played leading roles in pancreatitis susceptibility. In addition, the degree of unsaturation, the ratio of polyunsaturated fatty acids to monounsaturated fatty acids and the level of monounsaturated fatty acids showed causal associations with either decreased or increased pancreatitis susceptibility.ConclusionsOur MR study provided an atlas of causal associations of genetically predicted blood metabolites on pancreatitis, and offered genetic insights showing intervention in triglycerides and the supplementation of unsaturated fatty acids are potential strategies in the primary prevention of pancreatitis.
|
|
| 30. |
|
|
| 31. |
|
|
| 32. |
|
|
| 33. |
|
|
| 34. |
- Van Sundert, Kevin, et al.
(author)
-
When things get MESI : The Manipulation Experiments Synthesis Initiative—A coordinated effort to synthesize terrestrial global change experiments
- 2023
-
In: Global Change Biology. - : John Wiley & Sons. - 1354-1013 .- 1365-2486. ; 29:7, s. 1922-1938
-
Journal article (peer-reviewed)abstract
- Responses of the terrestrial biosphere to rapidly changing environmental conditions are a major source of uncertainty in climate projections. In an effort to reduce this uncertainty, a wide range of global change experiments have been conducted that mimic future conditions in terrestrial ecosystems, manipulating CO2, temperature, and nutrient and water availability. Syntheses of results across experiments provide a more general sense of ecosystem responses to global change, and help to discern the influence of background conditions such as climate and vegetation type in determining global change responses. Several independent syntheses of published data have yielded distinct databases for specific objectives. Such parallel, uncoordinated initiatives carry the risk of producing redundant data collection efforts and have led to contrasting outcomes without clarifying the underlying reason for divergence. These problems could be avoided by creating a publicly available, updatable, curated database. Here, we report on a global effort to collect and curate 57,089 treatment responses across 3644 manipulation experiments at 1145 sites, simulating elevated CO2, warming, nutrient addition, and precipitation changes. In the resulting Manipulation Experiments Synthesis Initiative (MESI) database, effects of experimental global change drivers on carbon and nutrient cycles are included, as well as ancillary data such as background climate, vegetation type, treatment magnitude, duration, and, unique to our database, measured soil properties. Our analysis of the database indicates that most experiments are short term (one or few growing seasons), conducted in the USA, Europe, or China, and that the most abundantly reported variable is aboveground biomass. We provide the most comprehensive multifactor global change database to date, enabling the research community to tackle open research questions, vital to global policymaking. The MESI database, freely accessible at doi.org/10.5281/zenodo.7153253, opens new avenues for model evaluation and synthesis-based understanding of how global change affects terrestrial biomes. We welcome contributions to the database on GitHub.
|
|
| 35. |
|
|
| 36. |
|
|
| 37. |
|
|
| 38. |
|
|
| 39. |
|
|
| 40. |
|
|
