ESPRESSO is a high-resolution-ultrastable spectrograph for the Very Large Telescope, whose commissioning will start in 2017. One of its key science goals is to test the stability of nature’s ...fundamental couplings with unprecedented accuracy and control of possible systematics. A total of 27 nights of the ESPRESSO Consortium’s guaranteed time observations (GTO) will be spent in testing the stability of the fine-structure constant and other fundamental couplings. A set of 14 priority optimal targets have been selected for the GTO period. Here we briefly discuss the criteria underlying this selection and describe the selected targets, and then we present detailed forecasts of the impact of these measurements on fundamental physics and cosmology, focusing on dark energy constraints and using future supernova Type Ia surveys as a comparison point. We show how canonical reconstructions of the dark energy equation of state are improved by the extended redshift range enabled by these spectroscopic measurements, and also quantify additional improvements foreseen for a future ELT-HIRES instrument.
The strong intervening absorption system at redshift 1.15 towards the very bright quasar HE 0515−4414 is the most studied absorber for measuring possible cosmological variations in the fine-structure ...constant,
α
. We observed HE 0515−4414 for 16.1 h with the Very Large Telescope and present here the first constraint on relative variations in
α
with parts-per-million (ppm) precision from the new ESPRESSO spectrograph: Δ
α
/
α
= 1.3 ± 1.3
stat
± 0.4
sys
ppm. The statistical uncertainty (1
σ
) is similar to the ensemble precision of previous large samples of absorbers and derives from the high signal-to-noise ratio achieved (≈105 per 0.4 km s
−1
pixel). ESPRESSO’s design, and the calibration of our observations with its laser frequency comb, effectively removed wavelength calibration errors from our measurement. The high resolving power of our ESPRESSO spectrum (
R
= 145 000) enabled the identification of very narrow components within the absorption profile, allowing a more robust analysis of Δ
α
/
α
. The evidence for the narrow components is corroborated by their correspondence with previously detected molecular hydrogen and neutral carbon. The main remaining systematic errors arise from ambiguities in the absorption profile modelling, effects from redispersing the individual quasar exposures, and convergence of the parameter estimation algorithm. All analyses of the spectrum, including systematic error estimates, were initially blinded to avoid human biases. We make our reduced ESPRESSO spectrum of HE 0515−4414 publicly available for further analysis. Combining our ESPRESSO result with 28 measurements, from other spectrographs, in which wavelength calibration errors have been mitigated yields a weighted mean Δ
α
/
α
= −0.5 ± 0.5
stat
± 0.4
sys
ppm at redshifts 0.6−2.4.
Astrophysical tests of the stability of dimensionless fundamental couplings, such as the fine-structure constant alpha and the proton-to-electron mass ratio mu , are an optimal probe of new physics. ...There is a growing interest in these tests, following indications of possible spacetime variations at the few parts per million level. Here we make use of the latest astrophysical measurements, combined with background cosmological observations, to obtain improved constraints on Bekenstein-type models for the evolution of both couplings. These are arguably the simplest models allowing for alpha and mu variations, and are characterized by a single free dimensionless parameter, zeta, describing the coupling of the underlying dynamical degree of freedom to the electromagnetic sector. In the former case we find that this parameter is constrained to be zeta sub( alpha ) < 4.8 x 10 super(-6)(improving previous constraints by a factor of 6), while in the latter (which we quantitatively compare to astrophysical measurements for the first time) we find zeta sub( mu )= (2.7+ or -3.1) x 10 super(-7); both of these are at the 99.7% confidence level. For zeta sub( alpha ) this constraint is about 20 times stronger than the one obtained from local weak equivalence principle tests, while for zeta sub( mu ) it is about 2 orders of magnitude weaker. We also discuss the improvements on these constraints to be expected from the forthcoming ESPRESSO and ELT-HIRES spectrographs, conservatively finding a factor of around 5 for the former and around 50 for the latter.
ABSTRACT
Cosmological observations usually map our present-day past light cone. However, it is also possible to compare different past light cones. This is the concept behind the redshift drift, a ...model-independent probe of fundamental cosmology. In simple physical terms, this effectively allows us to watch the Universe expand in real time. While current facilities only allow sensitivities several orders of magnitude worse than the expected signal, it should be possible to detect it with forthcoming ones. Here, we discuss the potential impact of measurements by three such facilities: the Extremely Large Telescope (the subject of most existing redshift drift forecasts), but also the Square Kilometre Array and intensity mapping experiments. For each of these we assume the measurement sensitivities estimated respectively in Liske et al. (2008), Klockner et al. (2015), and Yu, Zhang & Pen (2014). We focus on the role of these measurements in constraining dark energy scenarios, highlighting the fact that although on their own they yield comparatively weak constraints, they do probe regions of parameter space that are typically different from those probed by other experiments, as well as being redshift dependent. Specifically, we quantify how combinations of several redshift drift measurements at different redshifts, or combinations of redshift drift measurements with those from other canonical cosmological probes, can constrain some representative dark energy models. Our conclusion is that a model-independent mapping of the expansion of the universe from redshift z = 0 to z = 4 – a challenging but feasible goal for the next generation of astrophysical facilities – can have a significant impact on fundamental cosmology.
There is a growing interest in astrophysical tests of the stability of dimensionless fundamental couplings, such as the fine-structure constant α, as an optimal probe of new physics. The imminent ...arrival of the ESPRESSO spectrograph will soon enable significant gains in the precision and accuracy of these tests and widen the range of theoretical models that can be tightly constrained. Here we illustrate this by studying proposed extensions of the Bekenstein-type models for the evolution of α that allow different couplings of the scalar field to both dark matter and dark energy. We use a combination of current astrophysical and local laboratory data (from tests with atomic clocks) to show that these couplings are constrained to parts per million level, with the constraints being dominated by the atomic clocks. We also quantify the expected improvements from ESPRESSO and other future spectrographs, and briefly discuss possible observational strategies, showing that these facilities can improve current constraints by more than an order of magnitude.
The viability of SARS-CoV-2 on food surfaces and its propagation through the food chain has been discussed by several stakeholders, as it may represent a serious public health problem, bringing new ...challenges to the food system. This work shows for the first time that edible films can be used against SARS-CoV-2. Sodium alginate-based films containing gallic acid, geraniol, and green tea extract were evaluated in terms of their antiviral activity against SARS-CoV-2. The results showed that all these films have strong in vitro antiviral activity against this virus. However, a higher concentration of the active compound (1.25%) is needed for the film containing gallic acid to achieve similar results to those obtained for lower concentrations of geraniol and green tea extract (0.313%). Furthermore, critical concentrations of the active compounds in the films were used to evaluate their stability during storage. Results showed that gallic acid-loaded films lose their activity from the second week of storage, while films with geraniol and green tea extract only show a drop in activity after four weeks. These results highlight the possibility of using edible films and coatings as antiviral materials on food surfaces or food contact materials, which may help to reduce the spreading of viruses through the food chain.
•Active edible films showed in vitro antiviral activity against SARS-CoV-2.•Geraniol and green tea extract showed the highest activity at lower concentrations.•The films with higher activity maintain their performance during four weeks of storage.
The 2019 fire crisis in Amazonia dominated global news and triggered fundamental questions about the possible causes behind it. Here we performed an in-depth investigation of the drivers of active ...fire anomalies in the Brazilian Amazon biome. We assessed a 2003–2019 time-series of active fires, deforestation, and water deficit and evaluated potential drivers of active fire occurrence in 2019, at the biome-scale, state level, and local level. Our results revealed abnormally high monthly fire counts in 2019 for the states of Acre, Amazonas, and Roraima. These states also differed from others by exhibiting in this year extreme levels of deforestation. Areas in 2019 with active fire occurrence significantly greater than the average across the biome had, on average, three times more active fires in the three previous years, six times more deforestation in 2019, and five times more deforestation in the five previous years. Approximately one-third of yearly active fires from 2003 to 2019 occurred up to 1 km from deforested areas in the same year, and one-third of deforested areas in a given year were located up to 500 m from deforested areas in the previous year. These findings provide critical information to support strategic decisions for fire prevention policies and fire combat actions.
Patients with inflammatory bowel disease have a higher risk of thrombosis, which is associated with a higher morbidity and mortality. Most data about VTE are related to hospitalized patients with ...active disease, but several cases happen in the outpatient setting, and are not covered by current prophylaxis recommendation. As the knowledge of VTE in outpatients is still poor, the aim of this study is to evaluate the risk, clinical data and mortality of thrombosis in patients followed in our center, comparing our findings with the current prophylaxis recommendation.
The medical electronic chart of 1093 inflammatory bowel disease patients and their image exams were actively searched for words related to thrombosis, followed by charts reviewed to collect information about the event and data regarding clinical settings and thrombosis profile.
Overall, 654 Crohn's and 439 Colitis patients were included. Thrombosis prevalence was 5.1%,and mortality rate was higher in patients who had suffered thrombosis (10.71% vs. 1.45%, OR 8.0). Half of them developed thrombosis in the outpatient setting, 52% of these had disease activity, 17% had recent hospitalization, and 10% had previous thrombosis. In 27% of cases, diagnosis was done by routine image exams, with no clinical symptoms or previous history of thrombosis. None of them had used thromboprophylaxis. However, a great majority of patients who had thrombosis during hospitalization used heparin prophylaxis.
Inflammatory bowel disease patients who develop thrombosis have an increased mortality risk. A significant proportion of the events happened in patients without a clear thromboprophylaxis recommendation or in those receiving heparin prophylaxis.
The observational evidence for the acceleration of the Universe demonstrates that canonical theories of cosmology and particle physics are incomplete, if not incorrect, and that new physics is out ...there, waiting to be discovered. Forthcoming high-resolution ultrastable spectrographs will play a crucial role in this quest for new physics, by enabling a new generation of precision consistency tests. Here we focus on astrophysical tests of the stability of nature's fundamental couplings, and by using principal component analysis techniques further calibrated by existing VLT data we discuss how the improvements that can be expected with ESPRESSO and ELT-HIRES will impact on fundamental cosmology. In particular we show that a 20 to 30 night program on ELT-HIRES will allow it to play a leading role in fundamental cosmology.
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