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2.
Geophys Res Lett ; 44(13): 6570-6578, 2017 07 16.
Article in English | MEDLINE | ID: mdl-28989206

ABSTRACT

Prior to the arrival of the Dawn spacecraft at Ceres, the dwarf planet was anticipated to be ice-rich. Searches for morphological features related to ice have been ongoing during Dawn's mission at Ceres. Here we report the identification of pitted terrains associated with fresh Cerean impact craters. The Cerean pitted terrains exhibit strong morphological similarities to pitted materials previously identified on Mars (where ice is implicated in pit development) and Vesta (where the presence of ice is debated). We employ numerical models to investigate the formation of pitted materials on Ceres and discuss the relative importance of water ice and other volatiles in pit development there. We conclude that water ice likely plays an important role in pit development on Ceres. Similar pitted terrains may be common in the asteroid belt and may be of interest to future missions motivated by both astrobiology and in situ resource utilization.

3.
Science ; 355(6326): 719-722, 2017 02 17.
Article in English | MEDLINE | ID: mdl-28209893

ABSTRACT

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.

4.
Science ; 353(6303)2016 09 02.
Article in English | MEDLINE | ID: mdl-27701086

ABSTRACT

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.

5.
Nature ; 536(7614): 54-7, 2016 08 04.
Article in English | MEDLINE | ID: mdl-27362221

ABSTRACT

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.

6.
Nature ; 528(7581): 241-4, 2015 Dec 10.
Article in English | MEDLINE | ID: mdl-26659184

ABSTRACT

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.

7.
Rev. argent. endocrinol. metab ; 50(4): 219-232, dic. 2013. graf, tab
Article in Spanish | LILACS | ID: lil-708681

ABSTRACT

Objetivos: el objetivo de este artículo es informar acerca de la seguridad y la efectividad de iniciar o cambiar a un tratamiento con insulinas análogas en la subpoblación argentina del estudio A1chieve. Materiales y métodos: estudio observacional, de no intervención. En la cohorte argentina participaron 607 pacientes con diabetes tipo 2 (DM2), con o sin tratamiento previo con insulina, quienes inciaron un tratamiento con insulina aspártica bifásica 30, insulina detemir o insulina aspártica con o sin antidiabéticos orales (ADOs). Resultados: el grado de control metabólico al inicio del estudio, medido por HbA1c basal (± DE) fue pobre: 9,4 ± 2,1 %. A los 6 meses, se observó una reducción de HbA1c de -1,8 ± 2,1 % en la cohorte completa, y -2,3 ± 2,1% y -1,1 ± 1,8 % para los pacientes sin tratamiento previo con insulina y con tratamiento previo con insulina, respectivamente. En general, la tasa de hipoglucemia se incrementó en aquellos pacientes que recibieron insulina por primera vez, mientras que se observó una disminución en los pacientes que, previamente, recibían otras insulinas. Se observó un incremento del peso corporal (± DE) en los pacientes sin tratamiento previo con insulina (0,8 ± 4,3 kg). Conclusiones: en la población argentina del estudio A1chieve, se observó un control metabólico deficiente. Se logró una mejoría de la HbA1c al iniciar un tratamiento con análogos de insulina, ya sea en pacientes naïve usuarios previos de insulina,siendo una gran oportunidad para lograr amplias mejorías en el autocuidado y en el control metabólico, independientemente del tipo de regimen insulínico utilizado, con buena tolerabilidad y seguridad. Estos hallazgos coinciden con los resultados obtenidos en la cohorte completa del estudio.


Objectives: The aim of this paper is to report the safety and effectiveness of initiating or switching to insulin analogue therapy in the Argentinean subpopulation of the A1chieve study. Materials and methods: Observational, non-interventional study. The Argentinean cohort included 607 patients with type 2 diabetes (T2D), both insulin-naïve and prior insulin users, who initiated treatment with biphasic insulin aspart 30, insulin detemir or insulin aspart ± oral antidiabetic agents. Results: Baseline HbA1c (±SD) was poor: 9.4 ± 2.1 %. At 6 months, a reduction in the HbA1c of -1.8 ± 2.1 % was observed in the entire cohort, and of -2.3 ± 2.1 % and -1.1 ± 1.8 % in insulin-naïve patients and prior insulin users, respectively. Overall, the rate of hypoglycaemia increased in insulin-naïve patients, whereas a reduction was observed in those switching from other insulins. An increase in the body weight (±SD) was noted in insulin-naïve patients (0.8 ± 4.3 kg). Conclusions: Poor glycemic control was observed in the Argentinean population of the A1chieve study. The initiation of insulin analogue therapy showed an improvement in HbA1c, in both insulin-naïve patients and previous insulin users, which was a good opportunity for improvements in self-care and metabolic control, regardless of the type of insulin regimen used, with a good tolerability and safety profile. These findings are consistent with those obtained from the entire A1chieve study cohort.

8.
Rev. argent. endocrinol. metab ; 50(4): 219-232, dic. 2013. graf, tab
Article in Spanish | BINACIS | ID: bin-130228

ABSTRACT

Objetivos: el objetivo de este artículo es informar acerca de la seguridad y la efectividad de iniciar o cambiar a un tratamiento con insulinas análogas en la subpoblación argentina del estudio A1chieve. Materiales y métodos: estudio observacional, de no intervención. En la cohorte argentina participaron 607 pacientes con diabetes tipo 2 (DM2), con o sin tratamiento previo con insulina, quienes inciaron un tratamiento con insulina aspártica bifásica 30, insulina detemir o insulina aspártica con o sin antidiabéticos orales (ADOs). Resultados: el grado de control metabólico al inicio del estudio, medido por HbA1c basal (± DE) fue pobre: 9,4 ± 2,1 %. A los 6 meses, se observó una reducción de HbA1c de -1,8 ± 2,1 % en la cohorte completa, y -2,3 ± 2,1% y -1,1 ± 1,8 % para los pacientes sin tratamiento previo con insulina y con tratamiento previo con insulina, respectivamente. En general, la tasa de hipoglucemia se incrementó en aquellos pacientes que recibieron insulina por primera vez, mientras que se observó una disminución en los pacientes que, previamente, recibían otras insulinas. Se observó un incremento del peso corporal (± DE) en los pacientes sin tratamiento previo con insulina (0,8 ± 4,3 kg). Conclusiones: en la población argentina del estudio A1chieve, se observó un control metabólico deficiente. Se logró una mejoría de la HbA1c al iniciar un tratamiento con análogos de insulina, ya sea en pacientes na´ve usuarios previos de insulina,siendo una gran oportunidad para lograr amplias mejorías en el autocuidado y en el control metabólico, independientemente del tipo de regimen insulínico utilizado, con buena tolerabilidad y seguridad. Estos hallazgos coinciden con los resultados obtenidos en la cohorte completa del estudio.(AU)


Objectives: The aim of this paper is to report the safety and effectiveness of initiating or switching to insulin analogue therapy in the Argentinean subpopulation of the A1chieve study. Materials and methods: Observational, non-interventional study. The Argentinean cohort included 607 patients with type 2 diabetes (T2D), both insulin-na´ve and prior insulin users, who initiated treatment with biphasic insulin aspart 30, insulin detemir or insulin aspart ± oral antidiabetic agents. Results: Baseline HbA1c (±SD) was poor: 9.4 ± 2.1 %. At 6 months, a reduction in the HbA1c of -1.8 ± 2.1 % was observed in the entire cohort, and of -2.3 ± 2.1 % and -1.1 ± 1.8 % in insulin-na´ve patients and prior insulin users, respectively. Overall, the rate of hypoglycaemia increased in insulin-na´ve patients, whereas a reduction was observed in those switching from other insulins. An increase in the body weight (±SD) was noted in insulin-na´ve patients (0.8 ± 4.3 kg). Conclusions: Poor glycemic control was observed in the Argentinean population of the A1chieve study. The initiation of insulin analogue therapy showed an improvement in HbA1c, in both insulin-na´ve patients and previous insulin users, which was a good opportunity for improvements in self-care and metabolic control, regardless of the type of insulin regimen used, with a good tolerability and safety profile. These findings are consistent with those obtained from the entire A1chieve study cohort.(AU)

9.
Nature ; 504(7478): 122-5, 2013 Dec 05.
Article in English | MEDLINE | ID: mdl-24196707

ABSTRACT

Olivine is a major component of the mantle of differentiated bodies, including Earth. Howardite, eucrite and diogenite (HED) meteorites represent regolith, basaltic-crust, lower-crust and possibly ultramafic-mantle samples of asteroid Vesta, which is the lone surviving, large, differentiated, basaltic rocky protoplanet in the Solar System. Only a few of these meteorites, the orthopyroxene-rich diogenites, contain olivine, typically with a concentration of less than 25 per cent by volume. Olivine was tentatively identified on Vesta, on the basis of spectral and colour data, but other observations did not confirm its presence. Here we report that olivine is indeed present locally on Vesta's surface but that, unexpectedly, it has not been found within the deep, south-pole basins, which are thought to be excavated mantle rocks. Instead, it occurs as near-surface materials in the northern hemisphere. Unlike the meteorites, the olivine-rich (more than 50 per cent by volume) material is not associated with diogenite but seems to be mixed with howardite, the most common surface material. Olivine is exposed in crater walls and in ejecta scattered diffusely over a broad area. The size of the olivine exposures and the absence of associated diogenite favour a mantle source, but the exposures are located far from the deep impact basins. The amount and distribution of observed olivine-rich material suggest a complex evolutionary history for Vesta.

10.
Science ; 336(6082): 697-700, 2012 May 11.
Article in English | MEDLINE | ID: mdl-22582257

ABSTRACT

The mineralogy of Vesta, based on data obtained by the Dawn spacecraft's visible and infrared spectrometer, is consistent with howardite-eucrite-diogenite meteorites. There are considerable regional and local variations across the asteroid: Spectrally distinct regions include the south-polar Rheasilvia basin, which displays a higher diogenitic component, and equatorial regions, which show a higher eucritic component. The lithologic distribution indicates a deeper diogenitic crust, exposed after excavation by the impact that formed Rheasilvia, and an upper eucritic crust. Evidence for mineralogical stratigraphic layering is observed on crater walls and in ejecta. This is broadly consistent with magma-ocean models, but spectral variability highlights local variations, which suggests that the crust can be a complex assemblage of eucritic basalts and pyroxene cumulates. Overall, Vesta mineralogy indicates a complex magmatic evolution that led to a differentiated crust and mantle.

11.
Ann Ig ; 20(1): 39-47, 2008.
Article in Italian | MEDLINE | ID: mdl-18478675

ABSTRACT

Road traffic injuries among the elderly substantially differ from those seen in younger subjects in terms of crash mechanisms and injury profile. The study aimed at analysing road traffic injuries among subjects aged over 65 in terms of the magnitude of the problem, mobility patterns and risk factors for fatal outcomes. Mortality and morbidity rates for age groups (0-64; > or = 65) and for mobility pattern were computed annually from 1991-2005, based on the police reports of all road traffic crashes that occurred in Italy from 1991 to 2005. Crashes involving subjects aged over 65 were analysed through stepwise logistic regression with accident outcome (dead/ injured) as dependent variable and demographic, environmental, and crash factors as independent variables. A downward trend in mortality rates for road traffic injury among the elderly was registered: from 16.7 per 100,000 inhabitants in 1991 to 9.7 in 2005. On the contrary, the morbidity rates showed an 11% increase in the 15 years under analysis. When involved in a crash, an elderly aged over 85 had an almost four-fold risk of death compared to a subject aged 65-74 (OR 3.6; CI: 2.9-4.4). Older pedestrians were found to be the most vulnerable road users with a probability of dying for the impact 11 times that of car occupants (OR 10.9;CI: 7.9-15.1). A crash occurring among the elderly in the South of Italy appeared to lead to death to a greater extent than crashes occurring in the rest of Italy. Specific attention has to be paid to the elderly in the traffic environment: besides being more fragile, they are also considerably exposed to the traffic as vulnerable road users. Preventive interventions should target male elderly aged over 85, prioritizing interventions on pedestrians in the South of Italy.


Subject(s)
Accidents, Traffic/mortality , Mobility Limitation , Wounds and Injuries/mortality , Age Factors , Aged , Aged, 80 and over , Humans , Italy , Middle Aged , Risk Factors
12.
Occup Environ Med ; 57(12): 837-9, 2000 Dec.
Article in English | MEDLINE | ID: mdl-11077013

ABSTRACT

Two cases of paraoccupational asthma caused by toluene diisocyanate (TDI) are reported. The first patient was a metal worker in a machine shop situated near a factory producing polyurethane foam. Symptoms at work were not explainable by any specific exposure to irritants or allergens in the work site. As the patient recalled previous occasional work in the adjacent polyurethane factory with accompanying worsening of respiratory symptoms, a specific inhalation (SIC) test was performed with TDI, which confirmed the diagnosis of TDI asthma. The second case was a woman working part time as a secretary in the offices of her son's factory for varnishing wooden chairs. TDI was present in the products used in the varnishing shed. The SIC test confirmed the diagnosis of TDI asthma, despite the fact that the patient's job did not present risk of exposure to the substance. In both patients, symptoms disappeared when further exposure was avoided. These two cases confirm that paraoccupational exposure to TDI must be considered when evaluating patients with asthma not mediated by immunoglobulin E. They also suggest the need for more prospective studies evaluating the health risk for the general population living near polyurethane factories or other firms that use TDI.


Subject(s)
Asthma/chemically induced , Occupational Diseases/chemically induced , Toluene 2,4-Diisocyanate/adverse effects , Adult , Female , Humans , Male , Middle Aged , Paint/adverse effects , Polyurethanes/adverse effects
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