The pre-launch on-ground characterization of Ma_MISS spectrometer for ExoMars-Rosalind Franklin Rover mission. II. Radiometric calibration.

The Ma_MISS miniaturized spectrometer is integrated within the Drilling System of the ExoMars Rosalind Franklin Rover for Mars exploration. Here we focus on the on ground calibration campaign to obtain radiometric and linearity calibrations of the Ma_MISS instrument, while the first paper dealt with the spectral calibration [De Angelis et al., Rev. Sci. Instrum. 93, 123704 (2022)]. The experimental setup used to carry out radiometric calibration is described, as are the methods used for data processing and key parameter retrieval. In particular, the Spectrometer Transfer Function (Responsivity), Signal-to-Noise Ratio, and detector linearity are determined. In a third paper [De Sanctis et al., Planet. Sci. J. 3, 142 (2022)], validation of the Ma_MISS calibration results through spectral measurements performed on rock and synthetic targets during the radiometric calibration campaign is described.

The pre-launch on-ground characterization of Mars Multispectral Imager for Subsurface Studies (Ma_MISS) spectrometer for ExoMars rover mission: Spectral calibration.

The Ma_MISS spectrometer is integrated within the drilling system of the Rosalind Franklin ExoMars rover. This paper reports the on-ground calibration campaign performed on the spectrometer. Here, we focus on the spectral calibration of the instrument. The experimental setup used to carry out calibration is described, and the methods used for data processing and key parameters retrieval are explained. In particular, the spectral parameters such as (i) pixel central wavelengths, (ii) spectral response function, (iii) spectral resolution, (iv) sampling, and (v) range are determined. In a follow-up paper, the linearity and radiometric calibrations are described, while in De Sanctis et al. [Planet. Sci. J. 3, 142 (2022)], the validation of spectral measurements performed on synthetic and natural rock targets is presented.

Influence of permafrost, rock and ice glaciers on chemistry of high-elevation ponds (NW Italian Alps).

Permafrost degradation, rock-glacier thawing, and glacier retreat are influencing surface water quality at high elevations. However, there is a lack of knowledge on the dominant geochemical reactions occurring in different cryospheric conditions and how these reactions change during the ice-free season. In the Col d'Olen area (LTER site, NW Italian Alps), four ponds with similar sizes, located in basins with different cryospheric features (glacier, permafrost, rock glacier, none of these), are present in a geographically limited area. All ponds were sampled weekly in 2015 and partially in 2014. Major ions, selected trace elements, and biotic parameters (dissolved organic carbon-DOC, fluorescence index-FI, and nitrate) are examined to evidence the effect of different cryospheric features on water characteristics. Where cryospheric conditions occur chemical weathering is more intensive, with strong seasonal increase of major ions. Sulphide oxidation dominates in glacier and permafrost lying on acid rocks, probably driven by enhanced weathering of freshly exposed rocks in subglacial environment and recently deglaciated areas, and active layer thickness increase. Differently, carbonation dominates for the rock glacier lying on ultramafic rocks. There, high Ni concentrations originate from dissolution of Mg-bearing rocks in the landform. In all settings, pH neutralisation occurs because of the presence of secondary carbonate lithology and ultramafic rocks. Nitrate highest concentrations and changes occur in cryospheric settings while DOC and FI do not show strong differences and seasonal variations. The establishment of more frequent monitoring for water quality in high-elevated surface waters is necessary to provide greater statistical power to detect changes on longer time scales.

Localized aliphatic organic material on the surface of Ceres.

Organic compounds occur in some chondritic meteorites, and their signatures on solar system bodies have been sought for decades. Spectral signatures of organics have not been unambiguously identified on the surfaces of asteroids, whereas they have been detected on cometary nuclei. Data returned by the Visible and InfraRed Mapping Spectrometer on board the Dawn spacecraft show a clear detection of an organic absorption feature at 3.4 micrometers on dwarf planet Ceres. This signature is characteristic of aliphatic organic matter and is mainly localized on a broad region of ~1000 square kilometers close to the ~50-kilometer Ernutet crater. The combined presence on Ceres of ammonia-bearing hydrated minerals, water ice, carbonates, salts, and organic material indicates a very complex chemical environment, suggesting favorable environments to prebiotic chemistry.

Distribution of phyllosilicates on the surface of Ceres.

The dwarf planet Ceres is known to host phyllosilicate minerals at its surface, but their distribution and origin have not previously been determined. We used the spectrometer onboard the Dawn spacecraft to map their spatial distribution on the basis of diagnostic absorption features in the visible and near-infrared spectral range (0.25 to 5.0 micrometers). We found that magnesium- and ammonium-bearing minerals are ubiquitous across the surface. Variations in the strength of the absorption features are spatially correlated and indicate considerable variability in the relative abundance of the phyllosilicates, although their composition is fairly uniform. These data, along with the distinctive spectral properties of Ceres relative to other asteroids and carbonaceous meteorites, indicate that the phyllosilicates were formed endogenously by a globally widespread and extensive alteration process.

Bright carbonate deposits as evidence of aqueous alteration on (1) Ceres.

The typically dark surface of the dwarf planet Ceres is punctuated by areas of much higher albedo, most prominently in the Occator crater. These small bright areas have been tentatively interpreted as containing a large amount of hydrated magnesium sulfate, in contrast to the average surface, which is a mixture of low-albedo materials and magnesium phyllosilicates, ammoniated phyllosilicates and carbonates. Here we report high spatial and spectral resolution near-infrared observations of the bright areas in the Occator crater on Ceres. Spectra of these bright areas are consistent with a large amount of sodium carbonate, constituting the most concentrated known extraterrestrial occurrence of carbonate on kilometre-wide scales in the Solar System. The carbonates are mixed with a dark component and small amounts of phyllosilicates, as well as ammonium carbonate or ammonium chloride. Some of these compounds have also been detected in the plume of Saturn's sixth-largest moon Enceladus. The compounds are endogenous and we propose that they are the solid residue of crystallization of brines and entrained altered solids that reached the surface from below. The heat source may have been transient (triggered by impact heating). Alternatively, internal temperatures may be above the eutectic temperature of subsurface brines, in which case fluids may exist at depth on Ceres today.

Artifacts reduction in VIR/Dawn data.

Remote sensing images are generally affected by different types of noise that degrade the quality of the spectral data (i.e., stripes and spikes). Hyperspectral images returned by a Visible and InfraRed (VIR) spectrometer onboard the NASA Dawn mission exhibit residual systematic artifacts. VIR is an imaging spectrometer coupling high spectral and spatial resolutions in the visible and infrared spectral domain (0.25-5.0 µm). VIR data present one type of noise that may mask or distort real features (i.e., spikes and stripes), which may lead to misinterpretation of the surface composition. This paper presents a technique for the minimization of artifacts in VIR data that include a new instrument response function combining ground and in-flight radiometric measurements, correction of spectral spikes, odd-even band effects, systematic vertical stripes, high-frequency noise, and comparison with ground telescopic spectra of Vesta and Ceres. We developed a correction of artifacts in a two steps process: creation of the artifacts matrix and application of the same matrix to the VIR dataset. In the approach presented here, a polynomial function is used to fit the high frequency variations. After applying these corrections, the resulting spectra show improvements of the quality of the data. The new calibrated data enhance the significance of results from the spectral analysis of Vesta and Ceres.

Ammoniated phyllosilicates with a likely outer Solar System origin on (1) Ceres.

Studies of the dwarf planet (1) Ceres using ground-based and orbiting telescopes have concluded that its closest meteoritic analogues are the volatile-rich CI and CM carbonaceous chondrites. Water in clay minerals, ammoniated phyllosilicates, or a mixture of Mg(OH)2 (brucite), Mg2CO3 and iron-rich serpentine have all been proposed to exist on the surface. In particular, brucite has been suggested from analysis of the mid-infrared spectrum of Ceres. But the lack of spectral data across telluric absorption bands in the wavelength region 2.5 to 2.9 micrometres--where the OH stretching vibration and the H2O bending overtone are found--has precluded definitive identifications. In addition, water vapour around Ceres has recently been reported, possibly originating from localized sources. Here we report spectra of Ceres from 0.4 to 5 micrometres acquired at distances from ~82,000 to 4,300 kilometres from the surface. Our measurements indicate widespread ammoniated phyllosilicates across the surface, but no detectable water ice. Ammonia, accreted either as organic matter or as ice, may have reacted with phyllosilicates on Ceres during differentiation. This suggests that material from the outer Solar System was incorporated into Ceres, either during its formation at great heliocentric distance or by incorporation of material transported into the main asteroid belt.

Epidemiology of nosocomial infection in 125 Italian intensive care units.

AIM: A continuous infection surveillance program was conducted by GiViTI throughout 2006 in Intensive Care Units (ICUs). METHODS: This was a prospective epidemiological study carried out in 125 Italian intensive care units. All patients have been included in the study. Aside from the detailed clinical information collected for all patients, in cases of infection upon ICU admission and for the first site-specific episode that occurred during the patient's stay, the following data were collected: severity upon admission, micro-organisms and their antibiotic resistance patterns, subsequent multiple episodes in the same site, origin of infections and maximum severity reached. The diagnostic criteria for all infections are explicitly stated. RESULTS: A total of 34,472 patients entered the study. Infection upon admission was present in 12.6% of patients, with a high level of ICU and hospital mortality (29.4% and 38.7%, respectively). In 3148 patients one or more infections were reported as ICU-acquired with an overall incidence of 9.1% and an ICU and hospital mortality of 27.2% and 35.1%, respectively. Out of the device-related infections, ventilator-associated pneumonia was the most frequently diagnosed (8.9/1000 days on ventilator). Catheter-related blood stream infection was reported with a low incidence (1.9/1000 central venous catheter days). Nearly 20% of more than 5000 isolated microorganisms were classified as multi-drug resistant, with methicillin-resistant Staphylococcus aureus as the most frequently reported bug. CONCLUSIONS: The ad hoc expanded GiViTI software "Margherita2" allows continuous infection surveillance in Italian ICUs, annually providing an extensive and updated database. Interventions to improve infection prevention and patient safety should be tailored to accommodate these data.

Vancomycin-resistant Enterococcus spp. in marine environments from the West Coast of the USA.

AIMS: The aim of the study was to determine if vancomycin-resistant Enterococcus spp. [VRE] carrying vanA and/or vanB genes were present in public marine beaches and a fishing pier [2001-2003, 2008] from Washington and California [2008]. METHODS: PCR assays for the vanA and/or vanB genes with verification by DNA-DNA hybridization of the PCR products were used. Positive isolates were speciated using the BD BBL Crystal Identification and/or by sequencing the 16S ribosomal region. RESULTS: Eighteen (8%) of 227 isolates including Enterococcus faecalis, Enterococcus faecium, Enterococcus casseliflavus/gallinarum and a Staphylococcus epidermidis carrying vanA and/or vanB genes, from four of six Washington and one of two California sites, were identified. Selected VRE and the S. epidermidis were able to transfer their van genes to an E. faecalis recipient at frequencies ranging from 1.9 x 10(-6) to 6.7 x 10(-9). CONCLUSIONS: Vancomycin-resistant Enterococcus spp. was isolated from five of the seven sites suggesting that other North America public beaches could be the reservoirs for VRE and should be assessed. SIGNIFICANCE & IMPACT OF THE STUDY: This is the first report of isolation and characterization of VRE strains (and a vanB Staphylococcus sp.) from North American environmental sources suggesting that public beaches may be a reservoir for possible transmission of VRE to beach visitors.

Proposal of a flexible structural-organizing model for the Intensive Care Units.

BACKGROUND: The aim of this study was to verify the capability of the Italian Group for the Evaluation of Intervention in Intensive Care Medicine (Gruppo Italiano Valutazione Interventi in Terapia Intensiva, GiViTI) Intensive Care Units (ICUs) in providing high level care (HLC) and to develop a flexible organiziational model, allowing for different levels of care in each ICU. METHODS: Once the number of active beds, personnel and technology of each ICU were determined, we computed whether the available bed number and all available resources could provide HLC according to international standards. For ICUs lacking staff or equipment for safe HLC in all declared beds, we calculated the best combination between HLC and observation/monitoring beds with less need for nurses and technology (low level of care, LLC) in order to optimise the utilization of each bed. We also investigated the work organisation of physicians and nurses in these units. RESULTS: There are 2 070 available beds in the 293 GiViTI ICUs. To provide HLC according to international criteria, the beds would decrease to 80.9%, because 144 ICUs do not have nurses or equipment to provide HLC in each bed. In order to maximize the suitable use of available resources, these ICUs would have to reduce the HLC bed number using the regained nurse workload for LLC. Because of this, the total number of HLC beds would further decrease to 65.9% of all declared beds. During Sundays and holidays, the bed/doctor and the bed/nurse ratios increase in most ICUs. CONCLUSION: To maximize the staff and equipment resources available, the bed numbers of a general ICU providing HLC must vary, even daily, according to the level of care provided. This level is not always high for all patients present. Applying this organizing model to each ICU, we could have enough flexibility to face the different demands for assistance if the ICU is built as a large open space to achieve the best clinical model and use of resources.

Continuous quality improvement in intensive care medicine. The GiViTI Margherita Project - Report 2005.

AIM: The assessment of the quality of intensive care medicine is mandatory in the modern healthcare system. In Italy, the GiViTI (Gruppo Italiano per la Valutazione degli Interventi in Terapia Intensiva) network is working in this field since 1991 and it now involves 295 out of the about 450 Italian intensive care units (ICU). In 2002 GiViTI launched a project for the continuous quality assessment and improvement that is now joined by 180 ICUs. Data collected in 2005 are analyzed and presented. METHODS: All admitted patients were entered in a validated software, which performs a multitude of validity checks during the data entry. Data were further reviewed by the co-ordinating center; patients admitted in months with more than 10% of incomplete or inconsistent records in each ICU were excluded from the analysis. Each year, a multivariate logistic regression model is fitted to identify predictors of hospital mortality. Starting from the SAPS 2 and the 2004 GiViTI model predictions of hospital mortality, two calibration tables and curves are presented. RESULTS: In 2005, 180 Italian ICUs collected data on 55 246 patients. After excluding those admitted in months with an unjustified lower recruitment rate or with less than 90% of complete and consistent data, we had 52 816 (95.6%) valid cases. Although the rough hospital mortality in 2005 was 1% higher than in 2004 (22.6% vs 21.5%), the adjusted mortality shows a statistically significant 4% reduction (obser-ved-to-expected ratio: 0.96; 95% CI: 0.94-0.97). CONCLUSIONS: Italian ICUs in 2005 performed better than in 2004, at a parity of patient severity.