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International audience; Abstract. Accurate high-resolution measurements are essential to improve our understanding of environmental processes. Several chemical sensors relying on membrane separation extraction techniques have slow response times due to a dependence on equilibrium partitioning across the membrane separating the measured medium (i.e., a measuring chamber) and the medium of interest (i.e., a solvent). We present a new technique for deconvolving slow-sensor-response signals using statistical inverse theory; applying a weighted linear least-squares estimator with the growth law as a measurement model. The solution is regularized using model sparsity, assuming changes in the measured quantity occur with a certain time step, which can be selected based on domain-specific knowledge or L-curve analysis. The advantage of this method is that it (1) models error propagation, providing an explicit uncertainty estimate of the response-time-corrected signal; (2) enables evaluation of the solution self consistency; and (3) only requires instrument accuracy, response time, and data as input parameters. Functionality of the technique is demonstrated using simulated, laboratory, and field measurements. In the field experiment, the coefficient of determination (R2) of a slow-response methane sensor in comparison with an alternative fast-response sensor significantly improved from 0.18 to 0.91 after signal deconvolution. This shows how the proposed method can open up a considerably wider set of applications for sensors and methods suffering from slow response times due to a reliance on the efficacy of diffusion processes.

To improve our understanding of critical environmental processes, high resolution measurements with acceptable accuracy are essential. Unfortunately, the high spatiotemporal variability often associated with seabed seepage environments is prone to mischaracterization due to limitations in contemporary measurement techniques. This is particularly true for dissolved methane, which are often measured by labor- and time-intensive discrete water sampling and subsequent laboratory analysis. This often yields data with inadequate spatiotemporal resolution. A potential solution to this issue is using in-situ sensors in towing, profiling, mooring/observatory or glider operations. However, typical off-the-shelf sensors with adequate payload and power requirements currently lack the response time necessary for these applications. We offer a new, easy-to-implement, laboratory and field-tested post-processing tool for retrieving fast response data from commercially available methane sensors with slow response times. The tool is based on the framework of statistical inverse theory which in practice enables the user to obtain data with quantified, explicit (modeled) measurement uncertainty and at the resolution (i.e. response time) where the sensor can provide data with a respectable level of accuracy. The user needs no input besides the raw data, sensor accuracy, and response time. In our field experiment, we successfully retrieved data corresponding to a response time of 55 s using a sensor with a stated response time of 29 minutes. Being able to obtain high-resolution data from these types of sensors can considerably enhance the capacity to properly resolve the variability within methane seep sites and comprehend associated environmental processes.

The oxygen (𝛥17O) and nitrogen (𝛿15N) isotopic compositions of atmospheric nitrate (NO3-) are widely used as tracers of its formation pathways, precursor (nitrogen oxides NOx = nitric oxide NO + nitrogen NO2) emission sources, and physico-chemical processing. However, the critical lack of observations on the multi-isotopic composition of NO2 maintains significant uncertainties regarding the links between the isotopic composition of NOx and NO3-, which may bias estimates of the NO3- formation processes and the distribution of sources. We report here on the first simultaneous atmospheric observations of 𝛥17O and 𝛿15N in NO2 and NO3-. The measurements were carried out at sub-daily (ca. 3 h) resolution over two non-consecutive days in an Alpine city in February 2021. Important diurnal variabilities are observed in both NO2 and NO3- multi-isotopic composition. 𝛥17O of NO2 and NO3- range from 19.6 to 40.8 ‰ and 18.7 to 26 ‰, respectively. During both daytime and nighttime, the variability of 𝛥17O(NO2) is mainly driven by the oxidation of NO by ozone, with a substantial contribution from peroxy radicals in the morning. NO3- local mass balance equations, constrained by observed 𝛥17O(NO2), suggest that during the first day of sampling NO3- was formed locally from the oxidation of NO2 by hydroxyl radicals during the day, and via heterogeneous hydrolysis of dinitrogen pentoxide during the night. For the second day, calculated and observed 𝛥17O(NO3-) do not match, particularly daytime values. The effects on 𝛥17O(NO3-) of a Saharan dust event that occurred during the second day and winter boundary layer dynamics are discussed. 𝛿15N of NO2 and NO3- ranged from -10.0 to 19.7 ‰ and -4.2 to 14.8 ‰, respectively. Consistent with theoretical predictions of N isotope fractionation, the important variability of 𝛿15N(NO2) is explained by significant post-emission equilibrium N fractionation. After accounting for this effect, vehicle exhaust is found to be the primary source of NOx emissions at the sampling site. 𝛿15N(NO3-) is closely linked to 𝛿15N(NO2) variability, which bring further evidence of fast and local processing, but uncertainties on current N fractionation factors during NO2 to NO3- conversion are underscored. Overall, this detailed investigation highlights the potential and the necessity to use 𝛥17O and 𝛿15N in NO2 and NO3- to trace quantitatively the sources and formation chemistry of NO3-, particularly in urban environments in winter.

Carbon monoxide (CO) is a naturally occurring atmospheric trace gas, a regulated pollutant and one of the main components determining the oxidative capacity of the atmosphere. Evaluating climate-chemical models under different conditions than today and constraining past CO sources requires a reliable record of atmospheric CO mixing ratios ([CO]) since pre-industrial times. Here, we report the first continuous record of atmospheric [CO] for Southern Hemisphere (SH) high latitudes over the past three millennia. Our continuous record is a composite of three high-resolution Antarctic ice core gas records and firn air measurements from seven Antarctic locations. The ice core gas [CO] records were measured by continuous flow analysis (CFA) using an optical-feedback cavity-enhanced absorption spectrometer (OF-CEAS), achieving excellent external precision (2.8–8.8 ppbv, 2σ), and consistently low blanks (ranging from 4.1 ± 1.2 to 7.4 ± 1.4 ppbv), enabling paleo-atmospheric interpretations. Six new firn air [CO] Antarctic datasets collected between 1993 and 2016 CE at the DE08-2, DSSW19K, DSSW20K, South Pole, ABN, and Lock-In sites (and one previously published firn CO dataset at Berkner) were used to reconstruct the atmospheric history of CO from ~1897 CE using inverse modeling that incorporates the influence of gas transport in firn. Excellent consistency was observed between the youngest ice core gas [CO] and the [CO] from the base of the firn, and between the recent firn [CO] and atmospheric [CO] measurements at Mawson station (East Antarctica), yielding a consistent and contiguous record of CO across these different archives. Our Antarctic [CO] record is relatively stable from −835 to 1500 CE with mixing ratios within a 30–45 ppbv range (2σ). There is a ~5 ppbv decrease in [CO] to a minimum at around 1700 CE, during the Little Ice Age. CO mixing ratios then increase over time to reach a maximum of ~54 ppbv by ~1985 CE. Most of the industrial period [CO] growth occurred between about 1940 to 1985 CE, after which there was an overall [CO] decrease, as observed at atmospheric monitoring sites around the world and in Greenland firn air. Our Antarctic ice core gas CO observations differ from previously published records in two key aspects. First, our mixing ratios are significantly lower than reported previously, suggesting previous studies underestimated blank contributions. Second, our new CO record does not show a maximum in the late 1800s. The absence of CO peak around the turn of the century argues against there being a peak in Southern Hemisphere biomass burning at this time, which is in agreement with (i) other paleofire proxies such as ethane or acetylene and (ii) conclusions reached by paleofire modeling. The combined ice core and firn air CO history, spanning −835–1992 CE, extended to the present day by the Mawson atmospheric record, provides a useful benchmark for future atmospheric chemistry modeling studies.

RV Helmer Hanssen is the only vessel operating so far north (81 N) in October. One of the research questions addressed during this cruise is: Where do gas hydrate exist in the seabed and how much methane does it actually release? The CAGE 15-6 cruise explored potential gas hydrate charged sub-seabed environments and gas release zones at Storfjordrenna, Vestnesa and Svyatogor Ridge, Yermak Plateau, Sofia Basin and west of Prins Karls Foreland. Our route was traceable by www.sailwx.com. The weather forecasts from www.windyty.comwere used to prepare and adjust our cruise activities. In these Barents Sea-Arctic areas we carried out seismic profiling (mini GI 15/45 in 3 and large GI45/105 in 3) and 6 m long gravity coring for detecting gas hydrate, acoustic profiling (18, 38 and 120 kHz) for detecting gas flares in the water column, and CTD water sampling for gas analyses. Multibeam bathymetry mapping (EM300) data was collected on route for the entire cruise. We also ran echo sounder profiles along the NW Svalbard margin, across Yermak Plateau from west to east into the Sofia Basin and upslope towards the northern Svalbard margin. We reached the upper gas hydrate stability (GHSZ) theoretical outcrop zone but no acoustic evidence for extended gas release activity was found along the GHSZ outcrop zone at Yermak Plateau. The cruise may be known as: CAGE15_6

Previous Antarctic summer campaigns have shown unexpectedly high levels of oxidants in the lower atmosphere of the continental plateau and at coastal regions, with atmospheric hydroxyl radical (OH) concentrations up to 4 × 106 cm−3. Such high reactivity in the summer Antarctic boundary layer results in part from the emissions of nitrogen oxides (NOx ≡ NO + NO2) produced during photo-denitrification of the snowpack, but its underlying mechanisms are not yet fully understood, as some of the chemical species involved (NO2, in particular) have not yet been measured directly and accurately. To overcome this crucial lack of information, newly developed optical instruments based on absorption spectroscopy (incoherent broadband cavity-enhanced absorption spectroscopy, IBBCEAS) were deployed for the first time at Dome C (−75.10 lat., 123.33 long., 3233 m a.s.l.) during the 2019–2020 summer campaign to investigate snow–air–radiation interaction. These instruments directly measure NO2 with a detection limit of 30 pptv (parts per trillion by volume or 10−12 mol mol−1) (3σ). We performed two sets of measurements in December 2019 (4 to 9) and January 2020 (16 to 25) to capture the early and late photolytic season, respectively. Late in the season, the daily averaged NO2:NO​​​​​​​ ratio of 0.4 ± 0.4 matches that expected for photochemical equilibrium through Leighton's extended relationship involving ROx (0.6 ± 0.3). In December, however, we observed a daily averaged NO2:NO ratio of 1.3 ± 1.1, which is approximately twice the daily ratio of 0.7 ± 0.4 calculated for the Leighton equilibrium. This suggests that more NO2 is produced from the snowpack early in the photolytic season (4 to 9 December), possibly due to stronger UV irradiance caused by a smaller solar zenith angle near the solstice. Such a high sensitivity of the NO2:NO ratio to the sun's position is of importance for consideration in atmospheric chemistry models.

Bursts of carbon dioxide, released into the atmosphere and occurring on centennial time scales, were seen during the cold periods of the last glacial cycle but not in older or warmer conditions. Nehrbass-Ahles et al. present a record of atmospheric carbon dioxide concentrations retrieved from the European Project for Ice Coring in Antarctica Dome C ice core showing that these carbon dioxide jumps occurred during both cold and warm periods between 330,000 and 450,000 years ago. They relate these pulses to disruptions of the Atlantic meridional overturning circulation caused by freshwater discharge from ice sheets. Such rapid carbon dioxide increases could occur in the future if global warming also disrupts this ocean circulation pattern.Science, this issue p. 1000Pulse-like carbon dioxide release to the atmosphere on centennial time scales has only been identified for the most recent glacial and deglacial periods and is thought to be absent during warmer climate conditions. Here, we present a high-resolution carbon dioxide record from 330,000 to 450,000 years before present, revealing pronounced carbon dioxide jumps (CDJ) under cold and warm climate conditions. CDJ come in two varieties that we attribute to invigoration or weakening of the Atlantic meridional overturning circulation (AMOC) and associated northward and southward shifts of the intertropical convergence zone, respectively. We find that CDJ are pervasive features of the carbon cycle that can occur during interglacial climate conditions if land ice masses are sufficiently extended to be able to disturb the AMOC by freshwater input.

The global ocean is a net source of CH4 to the atmosphere. Among the natural processes, marine emissions are significant contributors with large uncertainties that deserves effort to improve current estimates, and eventually predict their trajectories in a changing climate. Oceanic CH4 emissions to the atmosphere can either be transported from seafloor or in situ produced in surface waters. Seafloor emissions include both CH4 emanating from CH4 hydrate degradation and from free gas in the sediment. Ultimately, CH4 enters the atmosphere across the sea-air interface either from bubbles rising from the seafloor or by diffusion of dissolved gas. Estimates of global marine emissions diverge widely due to very large uncertainties linked to limited data coverage, seasonal and methodological differences and the difficulty to capture the environmental factors that lead to high variability of the emissions.As the world’s largest natural anoxic waterbody, the semi-enclosed Black Sea (BS) is very sensitive to human and climate perturbations. It is characterized by widespread seafloor CH4 emissions from the shallow coast to the deep basin. One of the major issues that arises on the BS methane dynamics is the determine to what extent and in which quantity part of the urge amount of dissolved methane stored in the anoxic bottom water layer is transferred to the atmosphere.During the GHASS2 (Gas Hydrates, fluid Activities and Sediment deformations in the black Sea) cruise in September 2021, CH4transfer to the atmosphere has been investigated in the Western sector of the BS at sites with water depth ranging from 60 m to 1200m. CH4 partial pressures were measured in the surface water and in the atmosphere using optical spectrometers, respectively the SubOcean membrane inlet laser spectrometer (Grilli et al., 2021, https://doi.org/10.3389/feart.2021.626372) and an ICOS-calibrated commercial analyzer (Picarro G2401). We have also developed an open-path setup dedicated to shipborne measurement composed by an open-path CH4 analyzer Li-7700, a H2O-CO2 analyzer 7200RS from LiCor, a Gill 3D sonic anemometer, and an inertial navigation sensor (Lord). An inox structure was specifically designed to protrude by 1m the front mast of the R/V Pourquoi Pas? to install the open-path sensor.We present preliminary flux estimates comparison obtained from partial pressure gradient by the diffusive method with the experimental eddy covariance set-up. We also discuss our preliminary results in comparison with previous reports for the area and conclude on the respective challenges and relative basin-scale representativity of the various measurement techniques.

High resolution measurements with acceptable accuracy are crucial to increase our understanding of important environmental processes. The sharp spatial and temporal gradients which characterize seabed seepage environments often means that conventional measuring techniques fall short in representing seepage, content, and the environmental processes of interest. This is especially the case when it comes to measuring dissolved methane, which is still often done using discrete water sampling and subsequent laboratory analysis. This practice is time consuming, resulting in data with poor spatiotemporal resolution which is often unable to represent highly variable environmental processes. The overt solution to this problem is the employment of in situ sensors. Unfortunately, the common sensor design approach in off-the-shelf sensors, where measurements rely on a membrane equilibrium extraction technique and gas detection by some embedded device, are, while theoretically reliable, often plagued by high response times – especially in cold environments, making them unsuitable for applications where rapid changes are expected.We present a new, easily applicable, lab and field-tested method for recovering fast response data from off-the-shelf methane sensors relying on the principle of membrane separation by using the theoretical framework of statistical inverse theory. This framework allows us to model the uncertainty of the measurements obtained by the internal detector, giving fast response data where measurement uncertainty is explicitly defined – something which has not been possible in the past. The solution is constrained by model sparsity, which in practice gives the user data with the resolution at which the sensor is able to give measurements with a reasonable uncertainty. Furthermore, our method requires no additional input from the user other than what is provided from the manufacturer, such as detector accuracy and response time. Getting reliable fast response data from relatively affordable, off-the-shelf in situ sensors, means that these can be used in new applications such as profiling, towing, or on autonomous platforms such as gliders. This can considerably improve our ability to quantify dissolved methane and resolve and understand related environmental processes in the ocean.

International audience; Measurements of the water vapor absorption cross-sections at two spectral points of the 2.1 μm and 4.0 μm transparency windows are performed by optical feedback cavity enhanced absorption spectroscopy (OFCEAS). The self-continuum cross-section, C S , is measured for temperature values of 30 and 47 °C (303 and 320 K) at the 2853 cm −1 spectral point, corresponding to the lowest opacity region of the 4.0 μm transparency window. The C S values derived from the pressure squared dependence of the self-continuum, are found consistent with previous CEAS measurements in the considered window but significantly smaller than measurements by Fourier transform spectroscopy (FTS). The C S temperature dependence is discussed in relation with FTS measurements at high temperature. Foreign-continuum cross-sections, C F , are newly obtained from OFCEAS spectra of moist air in flow regime at the 4302 cm −1 spectral point of the low energy edge of the 2.1 μm window. After subtraction of the monomer and self-continuum contributions, C F values are derived from the linear variation of the foreign-continuum absorption with the product of the water vapor and air partial pressures. The measurements were performed for temperature values of 34 and 47 °C (307 and 320 K) and no significant temperature dependency was observed. The present C F value at 4302 cm −1 is gathered with previous CEAS measurements at seven spectral points of the 2.1 μm window. This consistent set of C F values is used to derive from a polynomial fit, the empirical frequency dependence of C F (ν) over the 4250-50 0 0 cm −1 range. Overall, the semi-empirical MT_CKD_3.5 values of C F are significantly underestimated in the centre of the considered window.

Previous Antarctic summer campaigns have shown unexpectedly high levels of oxidants in the lower atmosphere of the continental plateau as well as at coastal regions, with atmospheric hydroxyl radical (OH) concentrations up to 4 × 106 cm−3. Such high reactivity of the summer Antarctic boundary layer results in part from the emissions of nitrogen oxides (NOx ≡ NO + NO2) produced during photo-denitrification of the snowpack, but its underlying mechanisms are not yet fully understood as some of the chemical species involved (NO2, in particular) have not yet been measured directly and accurately. To overcome this crucial lack of information, newly developed optical instruments based on absorption spectroscopy (incoherent broadband cavity enhanced absorption spectroscopy or IBBCEAS) were deployed for the first time at Dome C (−75.10 lat., 123.33 long., 3,233 m a.s.l) during the 2019–2020 summer campaign to refine uncertainties in snow-air-radiation interaction. These instruments directly measure NO2 with a detection limit of 30 pptv (parts per trillion by volume or 10–12 mol mol−1) (3σ). We performed two sets of measurements in December 2019 (4th to 9th) and January 2020 (16th to 25th) to capture the early and late photolytic season, respectively. Late in the season, the daily averaged NO2 : NO ratio (0.4 ± 0.4) matches that expected for photochemical equilibrium through Leighton’s extended relationship involving ROx (0.6 ± 0.3). In December, however, we observe a daily averaged NO2 : NO ratio of 1.3 ± 1.1, which is approximately twice the daily ratio of 0.7 ± 0.4 calculated for Leighton equilibrium. This suggests that more NO2 is produced from the snowpack early in the photolytic season (December 4th to 9th) possibly due to stronger UV irradiance caused by a smaller solar zenith angle near the solstice. Such a high sensitivity of the NO2 : NO ratio to the sun’s position is of importance for consideration in atmospheric chemistry models.

Accurate, high resolution measurements are essential to improve our understanding of environmental processes. Several chemical sensors relying on membrane separation extraction techniques have slow response times due to a dependence on equilibrium partitioning across the membrane separating the measured medium (i.e., a measuring chamber) and the medium of interest (i.e., a solvent). We present a new technique for deconvolving slow sensor response signals using statistical inverse theory; applying a weighted linear least squares estimator with the growth-law as measurement model. The solution is regularized using model sparsity, assuming changes in the measured quantity occurs with a certain time-step, which can be selected based on domain-specific knowledge or L-curve analysis. The advantage of this method is that it: 1) models error propagation, providing an explicit uncertainty estimate of the response time corrected signal, 2) enables evaluation of the solutions self consistency, and 3) only requires instrument accuracy, response time, and data as input parameters. Functionality of the technique is demonstrated using simulated, laboratory, and field measurements. In the field experiment, the coefficient of determination (R2) of a slow response methane sensor in comparison with an alternative, fast response sensor, significantly improved from 0.18 to 0.91 after signal deconvolution. This shows how the proposed method can open up a considerably wider set of applications for sensors and methods suffering from slow response times due to a reliance on the efficacy of diffusion processes.

To fully decipher the role of nitrate photolysis on the atmospheric oxidative capacity in snow-covered regions, NOx flux must be determined with more precision than existing estimates. Here, we introduce a method based on dynamic flux chamber measurements for evaluating the NOx production by photolysis of snowpack nitrate in Antarctica. Flux chamber experiments were conducted for the first time in Antarctica, at the French-Italian station Concordia, Dome C (75◦06’S, 123◦19 20’E, 3233 m a.s.l) during the 2019-2020 summer campaign. Measurements were gathered with several snow samples of different ages ranging from newly formed drifted snow to 6-year-old firn.

Simultaneous measurement of C2H6 and CH4 concentrations, and of the δ13C - CH4 isotope ratio is demonstrated using a cavity-enhanced absorption spectroscopy technique in the mid-IR region. The spectrometer is compact and has been designed for field operation. It relies on optical-feedback-assisted injection of 3.3 µ m radiation from an interband cascade laser (ICL) into a V-shaped high-finesse optical cavity. A minimum absorption coefficient of 2.8 × 10 - 9 cm −1 is obtained in a single scan (0.1 s) over 0.7 cm −1 . Precisions of 3 ppbv, 11 ppbv, and 0.08 ‰ for C2H6 , CH4 , and δ13C - CH4 , respectively, are achieved after 400 s of integration time. Laboratory calibrations and tests of performance are reported here. They show the potential for the spectrometer to be embedded in a sensor probe for in situ measurements in ocean waters, which could have important applications for the understanding of the source and fate of hydrocarbons from the seabed and in the water column.

Objectives To review the evidence of the effects of centralization of cancer surgery on postoperative mortality. Methods We searched Medline, Embase, Cinahl, Cochrane and Scopus (up to November 2019) for studies that (i) assessed the effects of centralization of cancer surgery policies on in-hospital or 30-day mortality, or (ii) described changes in both postoperative mortality for a surgical intervention and degree of centralization using reduction in the number of hospitals or increases in the proportion of patients undergoing cancer surgery at high volume hospitals as proxy. PRISMA guidelines were followed. We estimated pooled odds ratios (OR) and conducted meta-regression to assess the relationship between degree of centralization and mortality. Results A total of 41 studies met our inclusion criteria of which 15 evaluated the effect of centralization policies on postoperative mortality after cancer surgery and 26 described concurrent changes in the degree of centralization and postoperative mortality. Policy evaluation studies mainly used before-after designs (n = 13) or interrupted time series analysis (n = 2), mainly focusing on pancreatic, oesophageal and gastric cancer. All but one showed some degree of reduction in postoperative mortality, with statistically significant effects demonstrated by six studies. The pooled odds ratio for centralization policy effect was 0.68 (95% Confidence interval: 0.54–0.85; I2 = 80%). Meta-regression analysis of the 26 descriptive studies found that an increase of the proportion of patients treated at high volume hospitals was associated with greater reduction in postoperative mortality. Conclusions Centralization of cancer surgery is associated with reduced postoperative mortality. However, existing evidence tends to be of low quality and estimates of the effect size are likely inflated. There is a need for prospective studies using more robust approaches, and for centralization efforts to be accompanied by well-designed evaluations of their effectiveness.

The recent detections of electric-quadrupole (E2) transitions in water vapor and magnetic-dipole (M1) transitions in carbon dioxide have opened a new field in molecular spectroscopy. While in their present status, the spectroscopic databases provide only electric-dipole (E1) transitions for polyatomic molecules (H$_2$O, CO$_2$, N$_2$O, CH$_4$, O$_3$…), the possible impact of weak E2 and M1 bands to the modeling of the Earth and planetary atmospheres has to be addressed. This is especially important in the case of carbon dioxide for which E2 and M1 bands may be located in spectral windows of weak E1 absorption. In the present work, a high sensitivity absorption spectrum of CO$_2$ is recorded by Optical-Feedback-Cavity Enhanced Absorption Spectroscopy (OFCEAS) in the 3.3 µm transparency window of carbon dioxide. The studied spectral interval corresponds to the region where M1 transitions of the $ν_{2}+ν_{3}$band of carbon dioxide were recently identified in the spectrum of the Martian atmosphere. Here, both M1 and E2 transitions of the $ν_{2}+ν_{3}$ band are detected by OFCEAS. Using recent ab initio calculations of the E2 spectrum of $^{12}$C$^{16}$O$_2$, intensity measurements of five M1 lines and three E2 lines allow us to disentangle the M1 and E2 contributions. Indeed, E2 intensity values (on the order of a few 10$^{–29}$ cm/molecule) are found in reasonable agreement with ab initio calculations while the intensity of the M1 lines (including an E2 contribution) agree very well with recent very long path measurements by Fourier Transform spectroscopy. We thus conclude that both E2 and M1 transitions should be systematically incorporated in the CO$_2$ line list provided by spectroscopic databases.

Previous Antarctic summer campaigns have shown unexpectedly high levels of oxidants in the continental interior as well as at coastal regions, with atmospheric hydroxyl radical (OH) concentrations up to 4 x 106 cm-3. It is now well established that such high reactivity of the summer Antarctic boundary layer results in part from the emissions of nitrogen oxides (NOx ≡ NO + NO2) produced during the photo-denitrification of the snowpack. Despite the numerous observations collected at various sites during previous campaigns such as ISCAT 1998, 2000, ANTCI, NITE-DC and OPALE, a robust quantification of the NOx emissions on a continental scale over Antarctica is still lacking. Only NO emissions were measured during ISCAT and the ratio NO2:NO was measured during NITE-DC and OPALE using indirect NO2 measurements. This leaves significant uncertainties on the snow-air-radiation interaction. To overcome this crucial lack of information, direct NO2 measurements are needed to estimate the NOx flux emissions with reduced uncertainties.For the first time, new developed optical instruments based on the IBB-CEAS technique and allowing direct measurement of NO2 with detection limit of 10 x 10-12 mol mol-1, (1σ), (Barbero et al., 2020) were deployed on the field during the 2019–2020 summer campaign at Dome C (75°06'S, 123°20'E, 3233m a.s.l). They were coupled with new designed dynamic flux chamber experiments. Snows of different ages ranging from newly formed drift snow to 16-20 year-old firn were sampled. Unexpectedly, the same daily average photolysis constant rate of (2.18 ± 0.38) x 10-8 s-1 (1σ) was estimated for the different type of snow samples, suggesting that the photolabile nitrate behaves as a single-family source with common photochemical properties. Daily summer NOx fluxes were estimated to be (4.4 ± 2.3) x 107 molec cm-2 s-1, 10 to 70 times less than what has been estimated in previous studies at Dome C and with uncertainties reduced by a factor up to 30. Using these results, we extrapolated an annual continental snow source NOx budget of 0.025 ± 0.013 Tg.N y-1, more than three times the N-budget of the stratospheric denitrification estimated to be 0.008 ± 0.003 Tg.N y-1 for Antarctica (Savarino et al., 2007), making the snowpack source a rather significant source in Antarctica. This innovative approach for the parameterization of nitrate photolysis using flux chamber experiments could significantly improve future global atmospheric models.

We are presenting here the findings of the reaction to the COVID-19 epidemic during the period March to June 2020 of those centres participating in the research EASY-NET which is on-going in Italy, funded by the Ministry of Health and co-founded by the Regional Health Authorities. The objective of EASY-NET is to evaluate the effectiveness of the audit and feedback (AF) strategies in different clinical and organizational settings in seven regions. As a negative consequence of the COVID-19 epidemic, the activities of the project have suddenly slowed down; nevertheless, the COVID-19 epidemic represented an opportunity to apply the AF methodology and support the healthcare within the regional authorities in order to manage and monitor the impact of this new disease. The reaction to the crisis on behalf of EASY-NET was inconsistent across the participating regions for various reasons. Factors which influenced the reaction levels in relation to the rapidity and efficiency of the implementation of the AF strategies were as follows: the varying epidemiological impact of the COVID-19 epidemic in the various territories, the different clinical and organizational context and availability of expert research teams together with AF procedures which had already been tested before the start of the epidemic.

The first of a series of four online meetings entitled "AF CONNECTIONS. In practice and in response to Covid-19", as part of the EASY-NET network program on the topic of AuditFeedback (AF), was an opportunity to present and discuss the first results of a survey carried out by the area working on AF, to describe the characteristics of AF interventions in the EASY-NET context. A reflection on the preliminary results of the investigation and on the cultural dimension of the importance of creating a bridge between the world of clinicians and the world of epidemiology, for a real and virtuous exchange of information.

Using new and previously published CO2 data from the EPICA Dome C ice core (EDC), we reconstruct a new high-resolution record of atmospheric CO2 during Marine Isotope Stage (MIS) 6 (190 to 135 ka) the penultimate glacial period. Similar to the last glacial cycle, where high-resolution data already exists, our record shows that during longer North Atlantic (NA) stadials, millennial CO2 variations during MIS 6 are clearly coincident with the bipolar seesaw signal in the Antarctic temperature record. However, during one short stadial in the NA, atmospheric CO2 variation is small ( ∼5 ppm) and the relationship between temperature variations in EDC and atmospheric CO2 is unclear. The magnitude of CO2 increase during Carbon Dioxide Maxima (CDM) is closely related to the NA stadial duration in both MIS 6 and MIS 3 (60–27 ka). This observation implies that during the last two glacials the overall bipolar seesaw coupling of climate and atmospheric CO2 operated similarly. In addition, similar to the last glacial period, CDM during the earliest MIS 6 show different lags with respect to the corresponding abrupt CH4 rises, the latter reflecting rapid warming in the Northern Hemisphere (NH). During MIS 6i at around 181.5± 0.3 ka, CDM 6i lags the abrupt warming in the NH by only 240± 320 years. However, during CDM 6iv ( 171.1± 0.2 ka) and CDM 6iii ( 175.4± 0.4 ka) the lag is much longer: 1290± 540 years on average. We speculate that the size of this lag may be related to a larger expansion of carbon-rich, southern-sourced waters into the Northern Hemisphere in MIS 6, providing a larger carbon reservoir that requires more time to be depleted.

We present a compact, affordable and robust instrument based on incoherent broadband cavity-enhanced absorption spectroscopy (IBBCEAS) for simultaneous detection of NOx, IO, CHOCHO and O3 in the 400–475 nm wavelength region. The instrument relies on the injection of a high-power LED source in a high-finesse cavity (F∼33 100), with the transmission signal being detected by a compact spectrometer based on a high-order diffraction grating and a charge-coupled device (CCD) camera. A minimum detectable absorption of 2.0×10-10 cm−1 was achieved within ∼22 min of total acquisition, corresponding to a figure of merit of 1.8×10-10 cm−1 Hz-1/2 per spectral element. Due to the multiplexing broadband feature of the setup, multi-species detection can be performed with simultaneous detection of NO2, IO, CHOCHO and O3 achieving detection limits of 11, 0.3, 10 ppt (parts per trillion) and 47 ppb (parts per billion) (1σ) within 22 min of measurement, respectively (half of the time is spent on the acquisition of the reference spectrum in the absence of the absorber, and the other half is spent on the absorption spectrum). The implementation on the inlet gas line of a compact ozone generator based on electrolysis of water allows for the measurement of NOx (NO+NO2) and therefore an indirect detection of NO with detection limits for NOx and NO of 10 and 21 ppt (1σ), respectively. The device has been designed to fit in a 19 in., 3U (5.25 in.) rack-mount case; weighs 15 kg; and has a total electrical power consumption of  W. The instrument can be employed to address different scientific objectives such as better constraining the oxidative capacity of the atmosphere, studying the chemistry of highly reactive species in atmospheric chambers as well as in the field and looking at the sources of glyoxal in the marine boundary layer to study possible implications on the formation of secondary aerosol particles.

ObjectivesTo describe the age- and sex-specific prevalence of SARS-CoV-2 disease (COVID-19) and its prognostic factors.DesignPopulation-based prospective cohort study on archive data.SettingPreventive services and hospital care in the province of Reggio Emilia, Northern Italy.ParticipantsAll 2653 symptomatic patients who tested positive for SARS-CoV-2 from February 27 to April 2, 2020 in the province of Reggio Emilia.Main outcome measuresHospitalization and death up to April 2, 2020.ResultsFemales had higher prevalence of infection than males below age 50 (2.61 vs. 1.84 ‰), but lower in older ages (16.49 vs. 20.86 ‰ over age 80). Case fatality rate reached 20.7% (22/106) in cases with more than 4 weeks follow up. After adjusting for age and comorbidities, men had a higher risk of hospitalization (hazard ratio (HR) 1.4 95% confidence interval (95% CI) 1.2 to 1.6) and of death (HR 1.6, 95% CI 1.2 to 2.1). Patients over age 80 compared to < age 50 had HR 7.1 (95% CI 5.4 to 9.3) and HR 27.8 (95% CI 12.5 to 61.7) for hospitalization and death, respectively. Immigrants had a higher risk of hospitalization (HR 1.3, 95% CI 0.99 to 1.81) than Italians and a similar risk of death. Risk of hospitalization and of death were higher in patients with heart failure (HR 1.6, 95% CI 1.2 to 2.1and HR 2.3, 95% CI 1.6 to 3.2, respectively), arrhythmia (HR 1.5, 95% CI 1.2 to 1.9 and HR 1.8, 95% CI 1.3 to 2.5, respectively), dementia (HR 1.2, 95% CI 0.9 to 1.8 and HR 1.8, 95% CI 1.1 to 2.8, respectively), ischemic heart disease (HR 1.3, 95% CI 1.0 to 1.7 and HR 1.7, 95% CI 1.2 to 2.5, respectively), diabetes (HR 1.5, 95% CI 1.3 to 1.9 and HR 1.6, 95% CI 1.1 to 2.2, respectively), and hypertensions(HR 1.4, 95% CI 1.2 to 2.6 and HR 1.6, 95% CI 1.2 to 2.1, respectively), while COPD increased the risk of hospitalization (HR 1.9, 95% CI 1.4 to 2.5) but not of death (HR 1.1, 95% CI 0.7 to 1.7). Previous use of ACE inhibitors has no effect on risk of death (HR 0.97, 95% CI 0.69 to 1.34)ConclusionsThe mechanisms underlying these associations are mostly unknown. A deeper understanding of the causal chain from infection, disease onset, and immune response to outcomes may explain how these prognostic factors act.

We present a compact, affordable and robust instrument based on Incoherent Broadband Cavity Enhanced Absorption Spectroscopy (IBBCEAS) for simultaneous detection of NOx, IO, CHOCHO and O3 in the 400–475 nm wavelength region. The instrument relies on the injection of a high-power LED source in a high-finesse cavity (F ∼ 36,100), with the trans- mission signal be detected by a compact spectrometer based on a high-order diffraction grating and a CCD camera. A minimum detectable absorption of 1.8 × 10−10 cm−1 was achieved within ∼ 22 minutes of total acquisition, corresponding to a figure of merit of 7.5 × 10−11 cm−1 Hz−1/2 per spectral element. Due to the multiplexing broadband feature of the setup, multi-species detection can be performed with simultaneous detection of NO2, IO, CHOCHO, and O3 achieving ultimate detection limits of 9, 0.3, 8 ppt and 40 ppb (1σ) within 22 min of measurement, respectively (half of the time spent on the acquisition of the reference spectrum in absence of absorber, and the other half on the absorption spectrum). The implementation on the inlet gas line of a compact ozone generator based on electrolysis of water allows the measurement of NOx (NO + NO2) and therefore an indirect detection of NO with detection limits for NOx and NO of 12 and 21 ppt (1σ), respectively. The device has been designed to fit in a 19′′, 3U rack-mount case, weights 15 kg and has a total electrical power consumption

Methane is an important greenhouse gas and an energy resource. Methane in sea water can originate from microbially-mediated organic matter (OM) degradation processes at shallow depth within the sediments, or from thermal cracking of refractory OM at deeper depth. On continental margins, this methane is stored in specific sedimentological bodies or as gas hydrates, or is released at the seafloor as submarine geological seeps followed by its oxidation in the water mass. However, methane released at the seafloor may not entirely be oxidized in the water column and a fraction of it may ultimately reach the atmosphere. The factors that govern the magnitude of methane transfer through the water column to the atmosphere remain poorly known. It has been identified that the amount of methane transferred to the atmosphere is strongly dependent on sites, and the thickness of the water column plays a critical role.The Black Sea shelf and margin are known to host a large number of strong methane seepages. It has therefore been identified as a perfect candidate to investigate the fate of methane released from the seafloor to the atmosphere. This area can also act as a proxy for investigating the fate of methane in potential scenarios of hydrate destabilization in a changing climate, which can become a societal problem in the future. In the frame of ENVRIplus H2020 project (www.envriplus.eu) we developed a joint pilot experiment to measure methane transfer from the seafloor to the atmosphere, in a pilot study involving European research infrastructures ICOS, Eurofleets, EMSO and ACTRIS. We investigated the influence of depth by mapping CH4 concentration and bubble distribution at two different sites, at 60m and 100m water depth, respectively. The pilot experiment developed joint monitoring strategy for methane detection at various levels starting from the seafloor and moving across the water column, the water/air interface and the atmosphere. An EK80 echosounder was used to identify emission areas through massive bubble plumes. The methodology applied integrates (1) sampling from the geosphere, hydrosphere and atmosphere for laboratory measurements of methane concentration by well-proven standard methods together with δ13CH4 analysis, (2) in situ measurements of methane concentration into the water column and the atmosphere, and (3) the deployment of a seafloor observatory for a short monitoring period (4-5 days) to evaluate the temporal variability of gas fluxes.During the cruise we found several occurrences of bubble plumes extending near the surface. Our measurements indicate that dissolved methane concentration drastically decreases from the seafloor to the water surface, highlighting its degradation and dispersion along the pathway to the atmosphere. The atmospheric data suggests a consistent input of marine methane to the atmosphere at the shallower site,. Our study highlights the observational challenges both for the measurement of methane from in situ and laboratory methods, and for the estimation of sea surface fluxes.

The isotopic composition of seawater represents an important fingerprint of water masses, containing information about conditions during their formation and evolution. Following the spatial and temporal variability of either δD or δ18O of water in the ocean will provide a direct link to the freshwater cycle, allowing to discriminate between different water masses, such as the one coming from glacier and sea ice melting, freshwater rivers and precipitations.Information from physical parameters (e.g. temperature and salinity) are not always enough for identifying the undergoing processes, and current knowledge of water isotopes or noble gases in the ocean remains very poor due to scarcity of measurements obtained from discrete sampling followed by laboratory analysis.Here we present a novel in-situ Membrane Inlet Laser Spectroscopy (MILS) sensor which is currently under development. The sensor will provide simultaneous and continuous measurements of water isotopes (both δD and δ18O, expected precision of ~0.05‰) and will be adapted for deployment from vessels, through boreholes into the ice shelves, and to be integrated in autonomous underwater vehicles (AUVs). The instrument will run on batteries, with an autonomy of ~12h.From 2021, the MILS sensor will be ready for field deployments, particular in the Southern Ocean, where high resolution water isotope data inside ice shelf cavities could be coupled with modelling approaches for better understanding the processes at work in ocean - ice shelf interactions, and better constraint the ice melting processes in Antarctica, which remains today a major challenge.

Pancreatic cancer is one of the most lethal tumours, and it is the fourth cause of cancer death in Europe. Despite its important public health impact, no effective treatments exist, nor are there high-visibility research efforts to improve care. This alarming situation is emblematic of a larger group of cancer diseases, known as neglected cancers. To address the impact of these diseases, the European Commission-supported Innovative Partnership for Action Against Cancer launched a multi-stakeholder initiative to determine key steps that healthcare systems can rapidly implement to improve their response. A working group comprising 20 representatives from European medical societies, patient associations, cancer plan organisations and other relevant European healthcare stakeholders was organised. A consensus process based on the results of different studies, discussion of research outcomes, and development and endorsement of draft statements resulted in 22 consensus recommendations (the Bratislava Statement). The statement argues that substantial improvements can be achieved in patient outcomes by centralising pancreatic cancer care around state-of-the-art reference centres, staffed by expert multidisciplinary teams capable of providing high-quality care. This organisational model requires a specific care framework encompassing primary, palliative and survivorship care, and a policy environment prioritising the use of quality criteria and performance assessments as well as research investments dedicated to prevention, risk prediction, early detection and diagnosis. In order to address the challenges posed by neglected cancers in general and pancreatic cancer in particular, a specific control strategy tailored to this reality is required.

The overuse of health care interventions is a problem which has clinical and economic implications. On a clinical level this means that ineffective interventions or effective interventions in inappropriate clinical indications are used. On an economic level it refers to allocative inefficiency which implies that these resources could possibly be used for interventions of major clinical utility. The contribution of health professionals in the context of reallocation disinvestment policies is still little investigated. This study involved 25 neurologists in the process of identifying low value interventions in the management of stroke, dementia, Parkinson's disease, amyotrophic lateral sclerosis and multiple sclerosis.The Nominal Group Technique was applied in the context of 5 Focus Groups (FG) in order to reach a consensus to identify and prioritize disinvestment opportunities in the treatment of the 5 neurodegenerative diseases. Qualitative data were coded, categorised, and analysed, applying the six-phase approach to thematic analysis, with the support of Atlas Ti7.Within 5 categories of "low value intervention", 25 clinical interventions were identified: 6 pharmacological, 16 diagnostic, 3 clinical-therapeutic. FG findings describe: how clinicians view the issue of disinvestment, both in absolute and relative terms; the factors which contribute to the use of low-value interventions; the explicit link between the disinvestment process and the reallocation of resources.This study revealed that factors that hinder the disinvestment of inappropriate practices involve elements that are not only technical or clinical, but also relational and care-related contexts.

Background The current economic context calls for rationalizing health resources that can be pursued through disinvestment from low value health technologies to invest in the best performing ones, ensuring high healthcare quality. Oncology is a field where, because of high costs of health technologies and rapid innovation, disinvestment is crucial. Methods On this basis, the research team investigated through a survey, based on a questionnaire, opinions and views of representatives of European countries about disinvestment, in terms of fields of application, potential advocates and barriers, specifically focusing on cancer care. Results A total of 17 questionnaires were filled in (response rate: 32.1%). The survey showed disinvestment is applied in several countries as a tool for containing health care expenditures and identifying obsolete technologies/ineffective interventions. Clinicians' resistance to change and industries' opposition are recognized as the most important barriers to the implementation of disinvestment policies. Potential targets of disinvestment in cancer are seen in diagnostic and therapeutic areas. Conclusion Despite the agreement on fields of waste and of disinvestment policies, operational methods to put disinvestment in place are lacking. Since they should rely on an inclusive assessment of the technology, Health Technology Assessment may represent a good approach.

Objectives We performed data collection concerning the coronavirus disease 2019 (COVID-19) pandemic-related delay in the diagnosis of cancers to individuate proper corrective procedures. Methods A comparison was made among the number of first pathologic diagnoses of malignancy made from weeks 11 to 20 of 2018, 2019, and 2020 at seven anatomic pathology units serving secondary care hospitals in northern-central Italy. Results Cancer diagnoses fell in 2020 by 44.9% compared with the average number recorded in 2018 and 2019. Melanoma and nonmelanoma skin cancer represented 56.7% of all missing diagnoses. The diagnostic decrease in colorectal (–46.6%), prostate (–45%), and bladder (–43.6%) cancer was the most relevant among internal malignancies; for prostate, however, high-grade tumors were only moderately affected (–21.7%). Conclusions Diagnosis of cutaneous malignancies was mostly affected by the lockdown; among internal malignancies, corrective actions were mostly needed for colorectal cancer and invasive bladder cancer.

Understanding natural carbon cycle/climate feedbacks on various time scales is highly relevant to reliably predict future climate changes. During the last two glacial periods, climate variations on millennial time scales were observed but the background conditions and duration of climate variations are different. Here we make use of contrasting climatic boundary conditions during the last two glacial periods to gain insight into the co-occurring carbon cycle changes. We reconstruct a new high-resolution record of atmospheric CO2 from the EPICA Dome C (EDC) ice core during Marine Isotope Stage (MIS) 6 (190 to 135 kyr BP). During long stadials in the North Atlantic (NA) region, atmospheric CO2 appears to be associated with the coeval Antarctic temperature changes at millennial time scale connected to the bipolar seesaw process. However, during one short stadial in the NA, atmospheric CO2 variation is negligible and the relationship between temperature variation in EDC and atmospheric CO2 is unclear. We suggest that the amplitude of CO2 variation may be affected by the duration of perturbations of the Atlantic Meridional Overturning Circulation (AMOC). In addition, similar to the last glacial period, in the earliest MIS 6 (MIS 6e and 6d, corresponding to 189 to 169 kyr BP), Carbon Dioxide Maxima (CDM) show different lags with respect to the corresponding abrupt CH4 jumps, the latter reflecting rapid warming in the Northern Hemisphere (NH). During MIS 6e at around 181.5 ± 0.3 kyr BP, CDM 6e.2 lags abrupt warming in the NH by only 200 ± 360 yrs. During MIS 6d which corresponds to CDM 6d.1 (171.1 ±0.2 kyr BP) and CDM 6d.2 (175.4 ± 0.4 kyr BP), the lag is much longer, i.e., 1,400 ± 375 yrs on average. The timing of CO2 variations with respect to abrupt warming in the NH may be affected by a major change in the organization of the AMOC from MIS 6e to MIS 6d.

Methane (CH4) in marine sediments has the potential to contribute to changes in the ocean and climate system. Physical and biochemical processes that are difficult to quantify with current standard methods such as acoustic surveys and discrete sampling govern the distribution of dissolved CH4 in oceans and lakes. Detailed observations of aquatic CH4 concentrations are required for a better understanding of CH4 dynamics in the water column, how it can affect lake and ocean acidification, the chemosynthetic ecosystem, and mixing ratios of atmospheric climate gases. Here we present pioneering high-resolution in situ measurements of dissolved CH4 throughout the water column over a 400 m deep CH4 seepage area at the continental slope west of Svalbard. A new fast-response underwater membrane-inlet laser spectrometer sensor demonstrates technological advances and breakthroughs for ocean measurements. We reveal decametre-scale variations in dissolved CH4 concentrations over the CH4 seepage zone. Previous studies could not resolve such heterogeneity in the area, assumed a smoother distribution, and therefore lacked both details on and insights into ongoing processes. We show good repeatability of the instrument measurements, which are also in agreement with discrete sampling. New numerical models, based on acoustically evidenced free gas emissions from the seafloor, support the observed heterogeneity and CH4 inventory. We identified sources of CH4, undetectable with echo sounder, and rapid diffusion of dissolved CH4 away from the sources. Results from the continuous ocean laser-spectrometer measurements, supported by modelling, improve our understanding of CH4 fluxes and related physical processes over Arctic CH4 degassing regions.