| 1. |
- Ablikim, M., et al.
(författare)
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Study of eta(1475) and X(1835) in radiative J/psi decays to gamma phi
- 2018
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Ingår i: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 97:5
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Tidskriftsartikel (refereegranskat)abstract
- The decay J/psi -> gamma gamma phi is studied using a sample of 1.31 x 10(9) J/psi events collected with the BESIII detector. Two structures around 1475 MeV/c(2) and 1835 MeV/c(2) are observed in the gamma phi invariant mass spectrum for the first time. With a fit on the gamma phi invariant mass, which takes into account the interference between the two structures, and a simple analysis of the angular distribution, the structure around 1475 MeV/c(2) is found to favor an assignment as the eta(1475) and the mass and width for the structure around 1835 MeV/c(2) are consistent with the X(1835). The statistical significances of the two structures are 13.5 sigma and 6.3 sigma, respectively. The results indicate that both eta(1475) and X(1835) contain a sizeable s (s) over bar component.
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| 2. |
- Yan, C., et al.
(författare)
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Size-dependent influence of NOx on the growth rates of organic aerosol particles
- 2020
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Ingår i: Science Advances. - : American Association for the Advancement of Science (AAAS). - 2375-2548. ; 6:22
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Tidskriftsartikel (refereegranskat)abstract
- Atmospheric new-particle formation (NPF) affects climate by contributing to a large fraction of the cloud condensation nuclei (CCN). Highly oxygenated organic molecules (HOMs) drive the early particle growth and therefore substantially influence the survival of newly formed particles to CCN. Nitrogen oxide (NOx) is known to suppress the NPF driven by HOMs, but the underlying mechanism remains largely unclear. Here, we examine the response of particle growth to the changes of HOM formation caused by NOx. We show that NOx suppresses particle growth in general, but the suppression is rather nonuniform and size dependent, which can be quantitatively explained by the shifted HOM volatility after adding NOx. By illustrating how NOx affects the early growth of new particles, a critical step of CCN formation, our results help provide a refined assessment of the potential climatic effects caused by the diverse changes of NOx level in forest regions around the globe.
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| 3. |
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| 4. |
- Lehtipalo, Katrianne, et al.
(författare)
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Multicomponent new particle formation from sulfuric acid, ammonia, and biogenic vapors
- 2018
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Ingår i: Science Advances. - : American Association for the Advancement of Science (AAAS). - 2375-2548. ; 4:12
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Tidskriftsartikel (refereegranskat)abstract
- A major fraction of atmospheric aerosol particles, which affect both air quality and climate, form from gaseous precursors in the atmosphere. Highly oxygenated organic molecules (HOMs), formed by oxidation of biogenic volatile organic compounds, are known to participate in particle formation and growth. However, it is not well understood how they interact with atmospheric pollutants, such as nitrogen oxides (NOx) and sulfur oxides (SOx) from fossil fuel combustion, as well as ammonia (NH3) from livestock and fertilizers. Here, we show how NOx suppresses particle formation, while HOMs, sulfuric acid, and NH3 have a synergistic enhancing effect on particle formation. We postulate a novel mechanism, involving HOMs, sulfuric acid, and ammonia, which is able to closely reproduce observations of particle formation and growth in daytime boreal forest and similar environments. The findings elucidate the complex interactions between biogenic and anthropogenic vapors in the atmospheric aerosol system.
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| 5. |
- Zhang, S. N., et al.
(författare)
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The high energy cosmic-radiation detection (HERD) facility onboard China's Space Station
- 2014
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Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE. - 9780819496126
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Konferensbidrag (refereegranskat)abstract
- The High Energy cosmic-Radiation Detection (HERD) facility is one of several space astronomy payloads of the cosmic lighthouse program onboard China's Space Station, which is planned for operation starting around 2020 for about 10 years. The main scientific objectives of HERD are indirect dark matter search, precise cosmic ray spectrum and composition measurements up to the knee energy, and high energy gamma-ray monitoring and survey. HERD is composed of a 3-D cubic calorimeter (CALO) surrounded by microstrip silicon trackers (STKs) from five sides except the bottom. CALO is made of about 104 cubes of LYSO crystals, corresponding to about 55 radiation lengths and 3 nuclear interaction lengths, respectively. The top STK microstrips of seven X-Y layers are sandwiched with tungsten converters to make precise directional measurements of incoming electrons and gamma-rays. In the baseline design, each of the four side SKTs is made of only three layers microstrips. All STKs will also be used for measuring the charge and incoming directions of cosmic rays, as well as identifying back scattered tracks. With this design, HERD can achieve the following performance: energy resolution of 1% for electrons and gamma-rays beyond 100 GeV, 20% for protons from 100 GeV to 1 PeV; electron/proton separation power better than 10-5; effective geometrical factors of >3 m2sr for electron and diffuse gamma-rays, >2 m2sr for cosmic ray nuclei. R and D is under way for reading out the LYSO signals with optical fiber coupled to image intensified CCD and the prototype of one layer of CALO.
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| 6. |
- King, Abby C., et al.
(författare)
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Community-Based Approaches to Reducing Health Inequities and Fostering Environmental Justice through Global Youth-Engaged Citizen Science
- 2021
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Ingår i: International journal of environmental research and public health. - : MDPI AG. - 1660-4601 .- 1661-7827. ; 18:3
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Tidskriftsartikel (refereegranskat)abstract
- Growing socioeconomic and structural disparities within and between nations have created unprecedented health inequities that have been felt most keenly among the world’s youth. While policy approaches can help to mitigate such inequities, they are often challenging to enact in under-resourced and marginalized communities. Community-engaged participatory action research provides an alternative or complementary means for addressing the physical and social environmental contexts that can impact health inequities. The purpose of this article is to describe the application of a particular form of technology-enabled participatory action research, called the Our Voice citizen science research model, with youth. An overview of 20 Our Voice studies occurring across five continents indicates that youth and young adults from varied backgrounds and with interests in diverse issues affecting their communities can participate successfully in multiple contributory research processes, including those representing the full scientific endeavor. These activities can, in turn, lead to changes in physical and social environments of relevance to health, wellbeing, and, at times, climate stabilization. The article ends with future directions for the advancement of this type of community-engaged citizen science among young people across the socioeconomic spectrum.
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| 7. |
- Zhang, S. -N, et al.
(författare)
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Introduction to the high energy cosmic-radiation detection (HERD) facility onboard China's future space station
- 2017
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Ingår i: Proceedings of Science. - : Sissa Medialab Srl.
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Konferensbidrag (refereegranskat)abstract
- The High Energy cosmic-Radiation Detection (HERD) facility is one of several space astronomy payloads onboard China's Space Station, which is planned for operation starting around 2025 for about 10 years. The main scientific objectives of HERD are searching for signals of dark matter annihilation products, precise cosmic electron (plus positron) spectrum and anisotropy measurements up to 10 TeV, precise cosmic ray spectrum and composition measurements up to the knee energy, and high energy gamma-ray monitoring and survey. HERD is composed of a 3-D cubic calorimeter (CALO) surrounded by microstrip silicon trackers (STKs) from five sides except the bottom. CALO is made of about 7,500 cubes of LYSO crystals, corresponding to about 55 radiation lengths and 3 nuclear interaction lengths, respectively. The top STK microstrips of six X-Y layers are sandwiched with tungsten converters to make precise directional measurements of incoming electrons and gamma-rays. In the baseline design, each of the four side STKs is made of only three layers microstrips. All STKs will also be used for measuring the charge and incoming directions of cosmic rays, as well as identifying back scattered tracks. With this design, HERD can achieve the following performance: energy resolution of 1% for electrons and gamma-rays beyond 100 GeV and 20% for protons from 100 GeV to 1 PeV; electron/proton separation power better than 10-5; effective geometrical factors of >3 m2sr for electron and diffuse gamma-rays, >2 m2sr for cosmic ray nuclei. R&D is under way for reading out the LYSO signals with optical fiber coupled to image intensified IsCMOS and CALO prototype of 250 LYSO crystals.
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| 8. |
- Bianchi, F., et al.
(författare)
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The SALTENA Experiment : Comprehensive Observations of Aerosol Sources, Formation, and Processes in the South American Andes
- 2022
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Ingår i: Bulletin of The American Meteorological Society - (BAMS). - 0003-0007 .- 1520-0477. ; 103:2, s. E212-E229
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents an introduction to the Southern Hemisphere High Altitude Experiment on Particle Nucleation and Growth (SALTENA). This field campaign took place between December 2017 and June 2018 (wet to dry season) at Chacaltaya (CHC), a GAW (Global Atmosphere Watch) station located at 5,240 m MSL in the Bolivian Andes. Concurrent measurements were conducted at two additional sites in El Alto (4,000 m MSL) and La Paz (3,600 m MSL). The overall goal of the campaign was to identify the sources, understand the formation mechanisms and transport, and characterize the properties of aerosol at these stations. State-of-the-art instruments were brought to the station complementing the ongoing permanent GAW measurements, to allow a comprehensive description of the chemical species of anthropogenic and biogenic origin impacting the station and contributing to new particle formation. In this overview we first provide an assessment of the complex meteorology, airmass origin, and boundary layer-free troposphere interactions during the campaign using a 6-month high-resolution Weather Research and Forecasting (WRF) simulation coupled with Flexible Particle dispersion model (FLEXPART). We then show some of the research highlights from the campaign, including (i) chemical transformation processes of anthropogenic pollution while the air masses are transported to the CHC station from the metropolitan area of La Paz-El Alto, (ii) volcanic emissions as an important source of atmospheric sulfur compounds in the region, (iii) the characterization of the compounds involved in new particle formation, and (iv) the identification of long-range-transported compounds from the Pacific or the Amazon basin. We conclude the article with a presentation of future research foci. The SALTENA dataset highlights the importance of comprehensive observations in strategic high-altitude locations, especially the undersampled Southern Hemisphere.
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| 9. |
- Andres-Martin, Miguel, et al.
(författare)
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Uncertainty in surface wind speed projections over the Iberian Peninsula: CMIP6 GCMs versus a WRF-RCM
- 2023
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Ingår i: Annals of the New York Academy of Sciences. - 0077-8923 .- 1749-6632. ; 1529:1, s. 101-108
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Tidskriftsartikel (refereegranskat)abstract
- This study assessed the projected near-surface wind speed (SWS) changes and variability over the Iberian Peninsula for the 21st century. Here, we compared Coupled Model Intercomparison Project Phase 6 global climate models (GCMs) with a higher spatial resolution regional climate model (RCM; ∼20km), known as WRF-CESM2, which was created by a dynamic downscaling of the Community Earth System Model version 2 (CESM2) using the Weather Research and Forecasting (WRF) model. Our analysis found that the GCMs tended to overestimate observed SWS for 1985–2014, while the higher spatial resolution of the WRF-CESM2 did not improve the accuracy and underestimated the SWS magnitude. GCMs project a decline of SWS under highshared socioeconomic pathways (SSPs) greenhouse concentrations, such as SSP370 and SSP585, while an interdecadal oscillation appears in SSP126 and SSP245 for the end of the century. The WRF-CESM2 under SSP585 predicts the opposite increasing SWS. Our results suggest that 21st-century projections of SWS are uncertain even for regionalized products and should be taken with caution.
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| 10. |
- Hugerth, Luisa W, et al.
(författare)
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Assessment of In Vitro and In Silico Protocols for Sequence-Based Characterization of the Human Vaginal Microbiome
- 2020
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Ingår i: mSphere. - : American Society for Microbiology. - 2379-5042. ; 5:6
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Tidskriftsartikel (refereegranskat)abstract
- The vaginal microbiome has been connected to a wide range of health outcomes. This has led to a thriving research environment but also to the use of conflicting methodologies to study its microbial composition. Here, we systematically assessed best practices for the sequencing-based characterization of the human vaginal microbiome. As far as 16S rRNA gene sequencing is concerned, the V1-V3 region performed best in silico, but limitations of current sequencing technologies meant that the V3-V4 region performed equally well. Both approaches presented very good agreement with qPCR quantification of key taxa, provided that an appropriate bioinformatic pipeline was used. Shotgun metagenomic sequencing presents an interesting alternative to 16S rRNA gene amplification and sequencing but requires deeper sequencing and more bioinformatic expertise and infrastructure. We assessed different tools for the removal of host reads and the taxonomic annotation of metagenomic reads, including a new, easy-to-build and -use reference database of vaginal taxa. This curated database performed as well as the best-performing previously published strategies. Despite the many advantages of shotgun sequencing, none of the shotgun approaches assessed here agreed with the qPCR data as well as the 16S rRNA gene sequencing.IMPORTANCE The vaginal microbiome has been connected to various aspects of host health, including susceptibility to sexually transmitted infections as well as gynecological cancers and pregnancy outcomes. This has led to a thriving research environment but also to conflicting available methodologies, including many studies that do not report their molecular biological and bioinformatic methods in sufficient detail to be considered reproducible. This can lead to conflicting messages and delay progress from descriptive to intervention studies. By systematically assessing best practices for the characterization of the human vaginal microbiome, this study will enable past studies to be assessed more critically and assist future studies in the selection of appropriate methods for their specific research questions.
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