430 research outputs found
New observations of NO2 in the upper troposphere from TROPOMI
Nitrogen oxides (NOxâĄNO+NO2) in the NOx-limited upper troposphere (UT) are long-lived and so have a large influence on the oxidizing capacity of the troposphere and formation of the greenhouse gas ozone. Models misrepresent NOx in the UT, and observations to address deficiencies in models are sparse. Here we obtain a year of near-global seasonal mean mixing ratios of NO2 in the UT (450â180âhPa) at 1âĂ1â by applying cloud-slicing to partial columns of NO2 from TROPOMI. This follows refinement of the cloud-slicing algorithm with synthetic partial columns from the GEOS-Chem chemical transport model. TROPOMI, prior to cloud-slicing, is corrected for a 13â% underestimate in stratospheric NO2 variance and a 50â% overestimate in free-tropospheric NO2 determined by comparison to Pandora total columns at high-altitude free-tropospheric sites at Mauna Loa, Izaña, and Altzomoni and MAX-DOAS and Pandora tropospheric columns at Izaña. Two cloud-sliced seasonal mean UT NO2 products for June 2019 to May 2020 are retrieved from corrected TROPOMI total columns using distinct TROPOMI cloud products that assume clouds are reflective boundaries (FRESCO-S) or water droplet layers (ROCINN-CAL). TROPOMI UT NO2 typically ranges from 20â30âpptv over remote oceans to >80âpptv over locations with intense seasonal lightning. Spatial coverage is mostly in the tropics and subtropics with FRESCO-S and extends to the midlatitudes and polar regions with ROCINN-CAL, due to its greater abundance of optically thick clouds and wider cloud-top altitude range. TROPOMI UT NO2 seasonal means are spatially consistent (R=0.6â0.8) with an existing coarser spatial resolution (5â latitudeâĂâ8â longitude) UT NO2 product from the Ozone Monitoring Instrument (OMI). UT NO2 from TROPOMI is 12â26âpptv more than that from OMI due to increase in NO2 with altitude from the OMI pressure ceiling (280âhPa) to that for TROPOMI (180âhPa), but possibly also due to altitude differences in TROPOMI and OMI cloud products and NO2 retrieval algorithms. The TROPOMI UT NO2 product offers potential to evaluate and improve representation of UT NOx in models and supplement aircraft observations that are sporadic and susceptible to large biases in the UT.This research has been supported by the European
Research Council under the European Unionâs Horizon 2020
research and innovation programme (through the Starting Grant
awarded to Eloise A. Marais, UpTrop (grant no. 851854))
RNA reference materials with defined viral RNA loads of SARS-CoV-2âA useful tool towards a better PCR assay harmonization
SARS-CoV-2, the cause of COVID-19, requires reliable diagnostic methods to track the circulation of this virus. Following the development of RT-qPCR methods to meet this diagnostic need in January 2020, it became clear from interlaboratory studies that the reported Ct values obtained for the different laboratories showed high variability. Despite this the Ct values were explored as a quantitative cut off to aid clinical decisions based on viral load. Consequently, there was a need to introduce standards to support estimation of SARS-CoV-2 viral load in diagnostic specimens. In a collaborative study, INSTAND established two reference materials (RMs) containing heat-inactivated SARS-CoV-2 with SARS-CoV-2 RNA loads of ~107 copies/mL (RM 1) and ~106 copies/mL (RM 2), respectively. Quantification was performed by RT-qPCR using synthetic SARS-CoV-2 RNA standards and digital PCR. Between November 2020 and February 2021, German laboratories were invited to use the two RMs to anchor their Ct values measured in routine diagnostic specimens, with the Ct values of the two RMs. A total of 305 laboratories in Germany were supplied with RM 1 and RM 2. The laboratories were requested to report their measured Ct values together with details on the PCR method they used to INSTAND. This resultant 1,109 data sets were differentiated by test system and targeted gene region. Our findings demonstrate that an indispensable prerequisite for linking Ct values to SARS-CoV-2 viral loads is that they are treated as being unique to an individual laboratory. For this reason, clinical guidance based on viral loads should not cite Ct values. The RMs described were a suitable tool to determine the specific laboratory Ct for a given viral load. Furthermore, as Ct values can also vary between runs when using the same instrument, such RMs could be used as run controls to ensure reproducibility of the quantitative measurements.Peer Reviewe
Synthesis and Antiplasmodial Activity of New IndoloneN-Oxide Derivatives
Synthesis and Antiplasmodial Activity of New IndoloneN-Oxide Derivative
Multidifferential study of identified charged hadron distributions in -tagged jets in proton-proton collisions at 13 TeV
Jet fragmentation functions are measured for the first time in proton-proton
collisions for charged pions, kaons, and protons within jets recoiling against
a boson. The charged-hadron distributions are studied longitudinally and
transversely to the jet direction for jets with transverse momentum 20 GeV and in the pseudorapidity range . The
data sample was collected with the LHCb experiment at a center-of-mass energy
of 13 TeV, corresponding to an integrated luminosity of 1.64 fb. Triple
differential distributions as a function of the hadron longitudinal momentum
fraction, hadron transverse momentum, and jet transverse momentum are also
measured for the first time. This helps constrain transverse-momentum-dependent
fragmentation functions. Differences in the shapes and magnitudes of the
measured distributions for the different hadron species provide insights into
the hadronization process for jets predominantly initiated by light quarks.Comment: All figures and tables, along with machine-readable versions and any
supplementary material and additional information, are available at
https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-013.html (LHCb
public pages
Study of the decay
The decay is studied
in proton-proton collisions at a center-of-mass energy of TeV
using data corresponding to an integrated luminosity of 5
collected by the LHCb experiment. In the system, the
state observed at the BaBar and Belle experiments is
resolved into two narrower states, and ,
whose masses and widths are measured to be where the first uncertainties are statistical and the second
systematic. The results are consistent with a previous LHCb measurement using a
prompt sample. Evidence of a new
state is found with a local significance of , whose mass and width
are measured to be and , respectively. In addition, evidence of a new decay mode
is found with a significance of
. The relative branching fraction of with respect to the
decay is measured to be , where the first
uncertainty is statistical, the second systematic and the third originates from
the branching fractions of charm hadron decays.Comment: All figures and tables, along with any supplementary material and
additional information, are available at
https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-028.html (LHCb
public pages
Measurement of the ratios of branching fractions and
The ratios of branching fractions
and are measured, assuming isospin symmetry, using a
sample of proton-proton collision data corresponding to 3.0 fb of
integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The
tau lepton is identified in the decay mode
. The measured values are
and
, where the first uncertainty is
statistical and the second is systematic. The correlation between these
measurements is . Results are consistent with the current average
of these quantities and are at a combined 1.9 standard deviations from the
predictions based on lepton flavor universality in the Standard Model.Comment: All figures and tables, along with any supplementary material and
additional information, are available at
https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-039.html (LHCb
public pages
GEMMOLOGICAL AND SPECTROSCOPIC STUDY WITH MOBILE INSTRUMENTS OF THE âEMERALDSâ FROM THE FRENCH CROWN JEWELS
International audienceRare are the scientific studies on gemstones from the French Crown Jewels, for the good reason that most of them were sold away by the French Third Republic in 1887, to get rid of this symbol of Royalty and Empire. Some unset stones were however put aside from the big sell, and given to some French museums, including the French Natural History Museum, the Louvre, and the Paris School of Mines. Some jewels have been bought back since the late 20 th by the Louvre, but mostly, the Crown Jewels are still spread out around the world. This paper is part of an ongoing project on the study of the French Crown Jewels owned the Paris School of Mines since 1887, in collaboration with the French Gemmological Laboratory (LFG). As this National Treasure is security sensitive, the project had to be conducted on site at the MINES Paristech Mineralogy Museum, using portable analytical instruments. In this first study, we are presenting the results acquired on some green coloured gems that used to be part of the coronation Crown of Napoleon III
Gemological study of emeralds from the Crown of Napoleon III at Paris School of Mines
International audienceAs most of the French Crown Jewels, the Coronation Crown of Napoleon III was dismantled in 1887 prior to the large auction intended to get rid of the foremost symbol of Royalty and Empire. The crown was created by the Emperor's jeweler, Alexandre Gabriel Lemonnier in 1855, depicting 8 golden eagles and palm leafs, adorned with diamonds and emeralds. The large 8 emeralds were given back to the Empress Eugenie, while the large 8 diamonds and other smaller diamonds were sold in 1887. The smaller 50 emeralds were put aside and donated to the Ecole Nationale Supérieure des Mines de Paris-Paris School of Minesbefore the auction (Morel, 1988). Lemonnier also created a similar but smaller crown for Empress Eugenie, which was kept in her family and eventually donated to the Louvre museum in 1988. In this study, we are reporting for the first time a gemological study of the remaining 45 emeralds in the collection of Paris School of Mines (Figure 1: 8 main emeralds, ENSMP69866). Our examination revealed that 41 out of 45 gems were indeed natural emeralds, presenting no evidence of clarity enhancement. Because of their gemological characteristics, we could established their provenance to most likely be Colombia, especially that they were mounted in 1855. Four samples however found to be artificial glass, possibly set on the crown since the beginning. This study is part of a worldwide intention of studying gemstones of historical meaning and significance
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