166 research outputs found

    Genomic and physiological resilience in extreme environments are associated with a secure attachment style

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    Understanding individual capability to adjust to protracted confinement and isolation may inform adaptive plasticity and disease vulnerability/resilience, and may have long-term implications for operations requiring prolonged presence in distant and restricted environments. Individual coping depends on many different factors encompassing psychological dispositional traits, endocrine reactivity and their underlying molecular mechanisms (e.g. gene expression). A positive view of self and others (secure attachment style) has been proposed to promote individual resilience under extreme environmental conditions. Here, we tested this hypothesis and investigated the underlying molecular mechanisms in 13 healthy volunteers confined and isolated for 12 months in a research station located 1670 km away from the south geographic pole on the Antarctic Plateau at 3233 m above sea level. Study participants, stratified for attachment style, were characterised longitudinally (before, during and after confinement) for their psychological appraisal of the stressful nature of the expedition, diurnal fluctuations in endocrine stress reactivity, and gene expression profiling (transcriptomics). Predictably, a secure attachment style was associated with reduced psychological distress and endocrine vulnerability to stress. In addition, while prolonged confinement and isolation remarkably altered overall patterns of gene expression, such alteration was largely reduced in individuals characterised by a secure attachment style. Furthermore, increased resilience was associated with a reduced expression of genes involved in energy metabolism (mitochondrial function and oxidative phosphorylation). Ultimately, our data indicate that a secure attachment style may favour individual resilience in extreme environments and that such resilience can be mapped onto identifiable molecular substrates

    Late Messinian mollusks and vertebrates from Moncucco Torinese, north-western Italy. Paleoecological and paleoclimatological implications

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    The systematic analysis of more than 20,000 fossils (Vertebrata and Mollusca), recovered from the post-evaporitic Messinian (5.41-5.33 Ma) succession of Moncucco Torinese (NW Italy), resulted in the identification of 90 vertebrate and 65 mollusk taxa that provide additional information about the paleoecological context and the paleoenvironmental settings of NW Italy slightly before the Mio-Pliocene boundary. Our analyses indicate a landscape dominated by open woodlands within a mosaic environment also including closed canopy forests, grasslands, rocky outcrops and limited water edges. The wide spectrum of habitats may have had a prominent role in determining the high paleobiodiversity observed in the paleocommunity of Moncucco Torinese. Slight variations in the abundances of the most common rodent species over the investigated succession are probably related to local changes in the paleolandscape. From a paleoclimatic point of view, the overall information provided by the fauna indicates mesic conditions in a subtropical climate, which is also consistent with the interpretation derived from paleobotanical and sedimentological analyses for the latest Messinian of Northern Italy

    Bryophyte, lichen, and vascular plant communities of badland grasslands show weak cross-taxon congruence but high local uniqueness in biancana pediments

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    Cross-taxon congruence, i.e., using certain taxonomic groups as surrogates for others, is receiving growing interest since it may allow decreasing efforts in biodiversity studies. In this work, we investigated the patterns of cross-taxon congruence in species richness and composition between communities of bryophytes, lichens, and vascular plants in different biancana grasslands of a Special Area of Conservation (SAC) of central Italy. We recorded species presence and abundance in 16 plots of 1 × 1 m size and analyzed the data using Procrustes correlation, co-correspondence analysis, and indicator species analysis. We did not highlight any correlation in species richness and composition between the three taxonomic groups. Conversely, the species composition of bryophyte communities was predictive of the species composition of lichen communities. Moreover, lichen richness was negatively correlated with the total cover of vascular plants. Indicator species analysis evidenced the presence of species from the three biotic communities being particularly related, at least at the local scale, to biancana pediments, like the bryophytes Didymodon acutus and Trichostomum crispulum, the lichens Enchylium tenax, Cladonia foliacea, and Psora decipiens, and the vascular plants Brachypodium distachyon, Parapholis strigosa, and Artemisia caerulescens subsp. cretacea. In the biancana pediments, acrocarp mosses, squamulose lichens, therophyte plants and chamaephyte plants coexisted. In spite of the weak cross-taxon congruence between the three taxonomic groups, this study could highlight a locally unique diversity of bryophytes, lichens, and vascular plants related to the extreme environment of biancana pediments, selected by high soil salinity and deposition from the upper eroded slope. Soil erosion and deposition in biancana badlands supports the increase of local multi-taxonomic plant diversity by creating unique ecosystems. Such biodiversity should be considered locally at risk of disappearance, due to the ongoing vanishing of biancana badlands in central Italy

    Attosecond pulse shaping using a seeded free-electron laser

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    Attosecond pulses are central to the investigation of valence- and core-electron dynamics on their natural timescales1–3. The reproducible generation and characterization of attosecond waveforms has been demonstrated so far only through the process of high-order harmonic generation4–7. Several methods for shaping attosecond waveforms have been proposed, including the use of metallic filters8,9, multilayer mirrors10 and manipulation of the driving field11. However, none of these approaches allows the flexible manipulation of the temporal characteristics of the attosecond waveforms, and they suffer from the low conversion efficiency of the high-order harmonic generation process. Free-electron lasers, by contrast, deliver femtosecond, extreme-ultraviolet and X-ray pulses with energies ranging from tens of microjoules to a few millijoules12,13. Recent experiments have shown that they can generate subfemtosecond spikes, but with temporal characteristics that change shot-to-shot14–16. Here we report reproducible generation of high-energy (microjoule level) attosecond waveforms using a seeded free-electron laser17. We demonstrate amplitude and phase manipulation of the harmonic components of an attosecond pulse train in combination with an approach for its temporal reconstruction. The results presented here open the way to performing attosecond time-resolved experiments with free-electron lasers

    A new method for measuring angle-resolved phases in photoemission

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    Quantum mechanically, photoionization can be fully described by the complex photoionization amplitudes that describe the transition between the ground state and the continuum state. Knowledge of the value of the phase of these amplitudes has been a central interest in photoionization studies and newly developing attosecond science, since the phase can reveal important information about phenomena such as electron correlation. We present a new attosecond-precision interferometric method of angle-resolved measurement for the phase of the photoionization amplitudes, using two phase-locked Extreme Ultraviolet pulses of frequency ω\omega and 2ω2\omega, from a Free-Electron Laser. Phase differences Δη~\Delta \tilde \eta between one- and two-photon ionization channels, averaged over multiple wave packets, are extracted for neon 2p2p electrons as a function of emission angle at photoelectron energies 7.9, 10.2, and 16.6 eV. Δη~\Delta \tilde \eta is nearly constant for emission parallel to the electric vector but increases at 10.2 eV for emission perpendicular to the electric vector. We model our observations with both perturbation and \textit{ab initio} theory, and find excellent agreement. In the existing method for attosecond measurement, Reconstruction of Attosecond Beating By Interference of Two-photon Transitions (RABBITT), a phase difference between two-photon pathways involving absorption and emission of an infrared photon is extracted. Our method can be used for extraction of a phase difference between single-photon and two-photon pathways and provides a new tool for attosecond science, which is complementary to RABBITT

    Infected pancreatic necrosis: outcomes and clinical predictors of mortality. A post hoc analysis of the MANCTRA-1 international study

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    : The identification of high-risk patients in the early stages of infected pancreatic necrosis (IPN) is critical, because it could help the clinicians to adopt more effective management strategies. We conducted a post hoc analysis of the MANCTRA-1 international study to assess the association between clinical risk factors and mortality among adult patients with IPN. Univariable and multivariable logistic regression models were used to identify prognostic factors of mortality. We identified 247 consecutive patients with IPN hospitalised between January 2019 and December 2020. History of uncontrolled arterial hypertension (p = 0.032; 95% CI 1.135-15.882; aOR 4.245), qSOFA (p = 0.005; 95% CI 1.359-5.879; aOR 2.828), renal failure (p = 0.022; 95% CI 1.138-5.442; aOR 2.489), and haemodynamic failure (p = 0.018; 95% CI 1.184-5.978; aOR 2.661), were identified as independent predictors of mortality in IPN patients. Cholangitis (p = 0.003; 95% CI 1.598-9.930; aOR 3.983), abdominal compartment syndrome (p = 0.032; 95% CI 1.090-6.967; aOR 2.735), and gastrointestinal/intra-abdominal bleeding (p = 0.009; 95% CI 1.286-5.712; aOR 2.710) were independently associated with the risk of mortality. Upfront open surgical necrosectomy was strongly associated with the risk of mortality (p < 0.001; 95% CI 1.912-7.442; aOR 3.772), whereas endoscopic drainage of pancreatic necrosis (p = 0.018; 95% CI 0.138-0.834; aOR 0.339) and enteral nutrition (p = 0.003; 95% CI 0.143-0.716; aOR 0.320) were found as protective factors. Organ failure, acute cholangitis, and upfront open surgical necrosectomy were the most significant predictors of mortality. Our study confirmed that, even in a subgroup of particularly ill patients such as those with IPN, upfront open surgery should be avoided as much as possible. Study protocol registered in ClinicalTrials.Gov (I.D. Number NCT04747990)

    Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

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    A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements
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