274 research outputs found
Taxonomic and functional analyses of intact microbial communities thriving in extreme, astrobiology-relevant, anoxic sites
Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAMBackground: Extreme terrestrial, analogue environments are widely used models to study the limits of life and to
infer habitability of extraterrestrial settings. In contrast to Earth’s ecosystems, potential extraterrestrial biotopes are
usually characterized by a lack of oxygen.
Methods: In the MASE project (Mars Analogues for Space Exploration), we selected representative anoxic analogue
environments (permafrost, salt-mine, acidic lake and river, sulfur springs) for the comprehensive analysis of their
microbial communities. We assessed the microbiome profile of intact cells by propidium monoazide-based
amplicon and shotgun metagenome sequencing, supplemented with an extensive cultivation effort.
Results: The information retrieved from microbiome analyses on the intact microbial community thriving in the
MASE sites, together with the isolation of 31 model microorganisms and successful binning of 15 high-quality
genomes allowed us to observe principle pathways, which pinpoint specific microbial functions in the MASE sites
compared to moderate environments. The microorganisms were characterized by an impressive machinery to
withstand physical and chemical pressures. All levels of our analyses revealed the strong and omnipresent
dependency of the microbial communities on complex organic matter. Moreover, we identified an extremotolerant
cosmopolitan group of 34 poly-extremophiles thriving in all sites.
Conclusions: Our results reveal the presence of a core microbiome and microbial taxonomic similarities between
saline and acidic anoxic environments. Our work further emphasizes the importance of the environmental,
terrestrial parameters for the functionality of a microbial community, but also reveals a high proportion of living
microorganisms in extreme environments with a high adaptation potential within habitability borders.
Keywords: Extreme environments, Microbiomes, Archaea, Bacteria, Propidium monoazide, Astrobiology, Spaceanalogue, Extremophiles, Extraterrestrial life, Metagenomic
Taxonomic and functional analyses of intact microbial communities thriving in extreme, astrobiology-relevant, anoxic sites
Background: Extreme terrestrial, analogue environments are widely used models to study the limits of life and to
infer habitability of extraterrestrial settings. In contrast to Earth’s ecosystems, potential extraterrestrial biotopes are
usually characterized by a lack of oxygen.
Methods: In the MASE project (Mars Analogues for Space Exploration), we selected representative anoxic analogue
environments (permafrost, salt-mine, acidic lake and river, sulfur springs) for the comprehensive analysis of their
microbial communities. We assessed the microbiome profile of intact cells by propidium monoazide-based
amplicon and shotgun metagenome sequencing, supplemented with an extensive cultivation effort.
Results: The information retrieved from microbiome analyses on the intact microbial community thriving in the
MASE sites, together with the isolation of 31 model microorganisms and successful binning of 15 high-quality
genomes allowed us to observe principle pathways, which pinpoint specific microbial functions in the MASE sites
compared to moderate environments. The microorganisms were characterized by an impressive machinery to
withstand physical and chemical pressures. All levels of our analyses revealed the strong and omnipresent
dependency of the microbial communities on complex organic matter. Moreover, we identified an extremotolerant
cosmopolitan group of 34 poly-extremophiles thriving in all sites.
Conclusions: Our results reveal the presence of a core microbiome and microbial taxonomic similarities between
saline and acidic anoxic environments. Our work further emphasizes the importance of the environmental,
terrestrial parameters for the functionality of a microbial community, but also reveals a high proportion of living
microorganisms in extreme environments with a high adaptation potential within habitability borders
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Global burden of 288 causes of death and life expectancy decomposition in 204 countries and territories and 811 subnational locations, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021
BACKGROUND Regular, detailed reporting on population health by underlying cause of death is fundamental for public health decision making. Cause-specific estimates of mortality and the subsequent effects on life expectancy worldwide are valuable metrics to gauge progress in reducing mortality rates. These estimates are particularly important following large-scale mortality spikes, such as the COVID-19 pandemic. When systematically analysed, mortality rates and life expectancy allow comparisons of the consequences of causes of death globally and over time, providing a nuanced understanding of the effect of these causes on global populations. METHODS The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 cause-of-death analysis estimated mortality and years of life lost (YLLs) from 288 causes of death by age-sex-location-year in 204 countries and territories and 811 subnational locations for each year from 1990 until 2021. The analysis used 56 604 data sources, including data from vital registration and verbal autopsy as well as surveys, censuses, surveillance systems, and cancer registries, among others. As with previous GBD rounds, cause-specific death rates for most causes were estimated using the Cause of Death Ensemble model-a modelling tool developed for GBD to assess the out-of-sample predictive validity of different statistical models and covariate permutations and combine those results to produce cause-specific mortality estimates-with alternative strategies adapted to model causes with insufficient data, substantial changes in reporting over the study period, or unusual epidemiology. YLLs were computed as the product of the number of deaths for each cause-age-sex-location-year and the standard life expectancy at each age. As part of the modelling process, uncertainty intervals (UIs) were generated using the 2·5th and 97·5th percentiles from a 1000-draw distribution for each metric. We decomposed life expectancy by cause of death, location, and year to show cause-specific effects on life expectancy from 1990 to 2021. We also used the coefficient of variation and the fraction of population affected by 90% of deaths to highlight concentrations of mortality. Findings are reported in counts and age-standardised rates. Methodological improvements for cause-of-death estimates in GBD 2021 include the expansion of under-5-years age group to include four new age groups, enhanced methods to account for stochastic variation of sparse data, and the inclusion of COVID-19 and other pandemic-related mortality-which includes excess mortality associated with the pandemic, excluding COVID-19, lower respiratory infections, measles, malaria, and pertussis. For this analysis, 199 new country-years of vital registration cause-of-death data, 5 country-years of surveillance data, 21 country-years of verbal autopsy data, and 94 country-years of other data types were added to those used in previous GBD rounds. FINDINGS The leading causes of age-standardised deaths globally were the same in 2019 as they were in 1990; in descending order, these were, ischaemic heart disease, stroke, chronic obstructive pulmonary disease, and lower respiratory infections. In 2021, however, COVID-19 replaced stroke as the second-leading age-standardised cause of death, with 94·0 deaths (95% UI 89·2-100·0) per 100 000 population. The COVID-19 pandemic shifted the rankings of the leading five causes, lowering stroke to the third-leading and chronic obstructive pulmonary disease to the fourth-leading position. In 2021, the highest age-standardised death rates from COVID-19 occurred in sub-Saharan Africa (271·0 deaths [250·1-290·7] per 100 000 population) and Latin America and the Caribbean (195·4 deaths [182·1-211·4] per 100 000 population). The lowest age-standardised death rates from COVID-19 were in the high-income super-region (48·1 deaths [47·4-48·8] per 100 000 population) and southeast Asia, east Asia, and Oceania (23·2 deaths [16·3-37·2] per 100 000 population). Globally, life expectancy steadily improved between 1990 and 2019 for 18 of the 22 investigated causes. Decomposition of global and regional life expectancy showed the positive effect that reductions in deaths from enteric infections, lower respiratory infections, stroke, and neonatal deaths, among others have contributed to improved survival over the study period. However, a net reduction of 1·6 years occurred in global life expectancy between 2019 and 2021, primarily due to increased death rates from COVID-19 and other pandemic-related mortality. Life expectancy was highly variable between super-regions over the study period, with southeast Asia, east Asia, and Oceania gaining 8·3 years (6·7-9·9) overall, while having the smallest reduction in life expectancy due to COVID-19 (0·4 years). The largest reduction in life expectancy due to COVID-19 occurred in Latin America and the Caribbean (3·6 years). Additionally, 53 of the 288 causes of death were highly concentrated in locations with less than 50% of the global population as of 2021, and these causes of death became progressively more concentrated since 1990, when only 44 causes showed this pattern. The concentration phenomenon is discussed heuristically with respect to enteric and lower respiratory infections, malaria, HIV/AIDS, neonatal disorders, tuberculosis, and measles. INTERPRETATION Long-standing gains in life expectancy and reductions in many of the leading causes of death have been disrupted by the COVID-19 pandemic, the adverse effects of which were spread unevenly among populations. Despite the pandemic, there has been continued progress in combatting several notable causes of death, leading to improved global life expectancy over the study period. Each of the seven GBD super-regions showed an overall improvement from 1990 and 2021, obscuring the negative effect in the years of the pandemic. Additionally, our findings regarding regional variation in causes of death driving increases in life expectancy hold clear policy utility. Analyses of shifting mortality trends reveal that several causes, once widespread globally, are now increasingly concentrated geographically. These changes in mortality concentration, alongside further investigation of changing risks, interventions, and relevant policy, present an important opportunity to deepen our understanding of mortality-reduction strategies. Examining patterns in mortality concentration might reveal areas where successful public health interventions have been implemented. Translating these successes to locations where certain causes of death remain entrenched can inform policies that work to improve life expectancy for people everywhere. FUNDING Bill & Melinda Gates Foundation
Methionine supplementation for multi-organ dysfunction in MetRS-related pulmonary alveolar proteinosis
International audienceIntroduction Pulmonary alveolar proteinosis related to mutations in the methionine tRNA synthetase ( MARS1 ) gene is a severe, early-onset disease that results in death before the age of 2 years in one-third of patients. It is associated with a liver disease, growth failure and systemic inflammation. As methionine supplementation in yeast models restored normal enzymatic activity of the synthetase, we studied the tolerance, safety and efficacy of daily oral methionine supplementation in patients with severe and early disease. Methods Four patients received methionine supplementation and were followed for respiratory, hepatic, growth, and inflammation-related outcomes. Their course was compared to those of historical controls. Reactive oxygen species (ROS) production by patient monocytes before and after methionine supplementation was also studied. Results Methionine supplementation was associated with respiratory improvement, clearance of the extracellular lipoproteinaceous material, and discontinuation of whole-lung lavage in all patients. The three patients who required oxygen or non-invasive ventilation could be weaned off within 60 days. Liver dysfunction, inflammation, and growth delay also improved or resolved. At a cellular level, methionine supplementation normalised the production of reactive oxygen species by peripheral monocytes. Conclusion Methionine supplementation was associated with important improvements in children with pulmonary alveolar proteinosis related to mutations in the MARS1 gene. This study paves the way for similar strategies for other tRNA synthetase deficiencies
Jet fragmentation transverse momentum distributions in pp and p-Pb collisions at , = 5.02 TeV
Jet fragmentation transverse momentum (j) distributions are measured in proton-proton (pp) and proton-lead (p-Pb) collisions at = 5.02 TeV with the ALICE experiment at the LHC. Jets are reconstructed with the ALICE tracking detectors and electromagnetic calorimeter using the anti-k algorithm with resolution parameter R = 0.4 in the pseudorapidity range |η| < 0.25. The j values are calculated for charged particles inside a fixed cone with a radius R = 0.4 around the reconstructed jet axis. The measured j distributions are compared with a variety of parton-shower models. Herwig and Pythia 8 based models describe the data well for the higher j region, while they underestimate the lower j region. The j distributions are further characterised by fitting them with a function composed of an inverse gamma function for higher j values (called the “wide component”), related to the perturbative component of the fragmentation process, and with a Gaussian for lower j values (called the “narrow component”), predominantly connected to the hadronisation process. The width of the Gaussian has only a weak dependence on jet transverse momentum, while that of the inverse gamma function increases with increasing jet transverse momentum. For the narrow component, the measured trends are successfully described by all models except for Herwig. For the wide component, Herwig and PYTHIA 8 based models slightly underestimate the data for the higher jet transverse momentum region. These measurements set constraints on models of jet fragmentation and hadronisation
Production of charged pions, kaons, and (anti-)protons in Pb-Pb and inelastic collisions at = 5.02 TeV
International audienceMid-rapidity production of , and ()p measured by the ALICE experiment at the LHC, in Pb-Pb and inelastic pp collisions at = 5.02 TeV, is presented. The invariant yields are measured over a wide transverse momentum () range from hundreds of MeV/ up to 20 GeV/. The results in Pb-Pb collisions are presented as a function of the collision centrality, in the range 090%. The comparison of the -integrated particle ratios, i.e. proton-to-pion (p/) and kaon-to-pion (K/) ratios, with similar measurements in Pb-Pb collisions at = 2.76 TeV show no significant energy dependence. Blast-wave fits of the spectra indicate that in the most central collisions radial flow is slightly larger at 5.02 TeV with respect to 2.76 TeV. Particle ratios (p/, K/) as a function of show pronounced maxima at 3 GeV/ in central Pb-Pb collisions. At high , particle ratios at 5.02 TeV are similar to those measured in pp collisions at the same energy and in Pb-Pb collisions at = 2.76 TeV. Using the pp reference spectra measured at the same collision energy of 5.02 TeV, the nuclear modification factors for the different particle species are derived. Within uncertainties, the nuclear modification factor is particle species independent for high and compatible with measurements at = 2.76 TeV. The results are compared to state-of-the-art model calculations, which are found to describe the observed trends satisfactorily
Measurements of the groomed and ungroomed jet angularities in pp collisions at = 5.02 TeV
International audienceThe jet angularities are a class of jet substructure observables which characterize the angular and momentum distribution of particles within jets. These observables are sensitive to momentum scales ranging from perturbative hard scatterings to nonperturbative fragmentation into final-state hadrons. We report measurements of several groomed and ungroomed jet angularities in pp collisions at = 5.02 TeV with the ALICE detector. Jets are reconstructed using charged particle tracks at midrapidity (|η| < 0.9). The anti-k algorithm is used with jet resolution parameters R = 0.2 and R = 0.4 for several transverse momentum {p}_{\mathrm{T}}^{\mathrm{ch}} ^{jet} intervals in the 20–100 GeV/c range. Using the jet grooming algorithm Soft Drop, the sensitivity to softer, wide-angle processes, as well as the underlying event, can be reduced in a way which is well-controlled in theoretical calculations. We report the ungroomed jet angularities, λ, and groomed jet angularities, λ, to investigate the interplay between perturbative and nonperturbative effects at low jet momenta. Various angular exponent parameters α = 1, 1.5, 2, and 3 are used to systematically vary the sensitivity of the observable to collinear and soft radiation. Results are compared to analytical predictions at next-to-leading-logarithmic accuracy, which provide a generally good description of the data in the perturbative regime but exhibit discrepancies in the nonperturbative regime. Moreover, these measurements serve as a baseline for future ones in heavy-ion collisions by providing new insight into the interplay between perturbative and nonperturbative effects in the angular and momentum substructure of jets. They supply crucial guidance on the selection of jet resolution parameter, jet transverse momentum, and angular scaling variable for jet quenching studies.[graphic not available: see fulltext
Neutron emission in ultraperipheral Pb-Pb collisions at = 5.02 TeV
In ultraperipheral collisions (UPCs) of relativistic nuclei without overlap of nuclear densities, the two nuclei are excited by the Lorentz-contracted Coulomb fields of their collision partners. In these UPCs, the typical nuclear excitation energy is below a few tens of MeV, and a small number of nucleons are emitted in electromagnetic dissociation (EMD) of primary nuclei, in contrast to complete nuclear fragmentation in hadronic interactions. The cross sections of emission of given numbers of neutrons in UPCs of Pb nuclei at ~TeV were measured with the neutron zero degree calorimeters (ZDCs) of the ALICE detector at the LHC, exploiting a similar technique to that used in previous studies performed at ~TeV. In addition, the cross sections for the exclusive emission of 1, 2, 3, 4 and 5 forward neutrons in the EMD, not accompanied by the emission of forward protons, and thus mostly corresponding to the production of Pb, respectively, were measured for the first time. The predictions from the available models describe the measured cross sections well. These cross sections can be used for evaluating the impact of secondary nuclei on the LHC components, in particular, on superconducting magnets, and also provide useful input for the design of the Future Circular Collider (FCC-hh).In ultraperipheral collisions (UPCs) of relativistic nuclei without overlap of nuclear densities, the two nuclei are excited by the Lorentz-contracted Coulomb fields of their collision partners. In these UPCs, the typical nuclear excitation energy is below a few tens of MeV, and a small number of nucleons are emitted in electromagnetic dissociation (EMD) of primary nuclei, in contrast to complete nuclear fragmentation in hadronic interactions. The cross sections of emission of given numbers of neutrons in UPCs of Pb208 nuclei at sNN=5.02 TeV were measured with the neutron zero degree calorimeters (ZDCs) of the ALICE detector at the LHC, exploiting a similar technique to that used in previous studies performed at sNN=2.76 TeV. In addition, the cross sections for the exclusive emission of one, two, three, four, and five forward neutrons in the EMD, not accompanied by the emission of forward protons, and thus mostly corresponding to the production of Pb207,206,205,204,203, respectively, were measured for the first time. The predictions from the available models describe the measured cross sections well. These cross sections can be used for evaluating the impact of secondary nuclei on the LHC components, in particular, on superconducting magnets, and also provide useful input for the design of the Future Circular Collider (FCC-hh).In ultraperipheral collisions (UPCs) of relativistic nuclei without overlap of nuclear densities, the two nuclei are excited by the Lorentz-contracted Coulomb fields of their collision partners. In these UPCs, the typical nuclear excitation energy is below a few tens of MeV, and a small number of nucleons are emitted in electromagnetic dissociation (EMD) of primary nuclei, in contrast to complete nuclear fragmentation in hadronic interactions. The cross sections of emission of given numbers of neutrons in UPCs of Pb nuclei at TeV were measured with the neutron zero degree calorimeters (ZDCs) of the ALICE detector at the LHC, exploiting a similar technique to that used in previous studies performed at TeV. In addition, the cross sections for the exclusive emission of one, two, three, four, and five forward neutrons in the EMD, not accompanied by the emission of forward protons, and thus mostly corresponding to the production of Pb, respectively, were measured for the first time. The predictions from the available models describe the measured cross sections well. These cross sections can be used for evaluating the impact of secondary nuclei on the LHC components, in particular, on superconducting magnets, and also provide useful input for the design of the Future Circular Collider (FCC-hh)
Inclusive quarkonium production in pp collisions at TeV
This article reports on the inclusive production cross section of several quarkonium states, , , , , and , measured with the ALICE detector at the LHC, in \pp collisions at TeV. The analysis is performed in the dimuon decay channel at forward rapidity (). The measured cross sections, assuming unpolarized quarkonia, are: b, b, nb, nb, and nb, where the first (second) uncertainty is the statistical (systematic) one. The transverse-momentum () and rapidity () differential cross sections for , , , and the -to- cross section ratios are presented. For the first time, the cross sections of the three states, as well as the one as a function of and , are measured at TeV at forward rapidity. These measurements also significantly extend the reach with respect to previously published results. A comparison with ALICE measurements in pp collisions at , 7, 8, and 13 TeV is presented and the energy dependence of quarkonium production cross sections is discussed. Finally, the results are compared with the predictions from several production models
Multiplicity dependence of (multi-)strange hadron production in proton-proton collisions at = 13 TeV
The production rates and the transverse momentum distribution of strange hadrons at mid-rapidity () are measured in proton-proton collisions at = 13 TeV as a function of the charged particle multiplicity, using the ALICE detector at the LHC. The production rates of , , , and increase with the multiplicity faster than what is reported for inclusive charged particles. The increase is found to be more pronounced for hadrons with a larger strangeness content. Possible auto-correlations between the charged particles and the strange hadrons are evaluated by measuring the event-activity with charged particle multiplicity estimators covering different pseudorapidity regions. When comparing to lower energy results, the yields of strange hadrons are found to depend only on the mid-rapidity charged particle multiplicity. Several features of the data are reproduced qualitatively by general purpose QCD Monte Carlo models that take into account the effect of densely-packed QCD strings in high multiplicity collisions. However, none of the tested models reproduce the data quantitatively. This work corroborates and extends the ALICE findings on strangeness production in proton-proton collisions at 7 TeV
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