Characteristics, Origins, and Biosignature Preservation Potential of Carbonate-Bearing Rocks Within and Outside of Jezero Crater.

Carbonate minerals have been detected in Jezero crater, an ancient lake basin that is the landing site of the Mars 2020 Perseverance rover, and within the regional olivine-bearing (ROB) unit in the Nili Fossae region surrounding this crater. It has been suggested that some carbonates in the margin fractured unit, a rock unit within Jezero crater, formed in a fluviolacustrine environment, which would be conducive to preservation of biosignatures from paleolake-inhabiting lifeforms. Here, we show that carbonate-bearing rocks within and outside of Jezero crater have the same range of visible-to-near-infrared carbonate absorption strengths, carbonate absorption band positions, thermal inertias, and morphologies. Thicknesses of exposed carbonate-bearing rock cross-sections in Jezero crater are ∼75-90 m thicker than typical ROB unit cross-sections in the Nili Fossae region, but have similar thicknesses to ROB unit exposures in Libya Montes. These similarities in carbonate properties within and outside of Jezero crater is consistent with a shared origin for all of the carbonates in the Nili Fossae region. Carbonate absorption minima positions indicate that both Mg- and more Fe-rich carbonates are present in the Nili Fossae region, consistent with the expected products of olivine carbonation. These estimated carbonate chemistries are similar to those in martian meteorites and the Comanche carbonates investigated by the Spirit rover in Columbia Hills. Our results indicate that hydrothermal alteration is the most likely formation mechanism for non-deltaic carbonates within and outside of Jezero crater.

Extreme philopatry and genetic diversification at unprecedented scales in a seabird.

Effective conservation requires maintenance of the processes underlying species divergence, as well as understanding species' responses to episodic disturbances and long-term change. We explored genetic population structure at a previously unrecognized spatial scale in seabirds, focusing on fine-scale isolation between colonies, and identified two distinct genetic clusters of Barau's Petrels (Pterodroma baraui) on Réunion Island (Indian Ocean) corresponding to the sampled breeding colonies separated by 5 km. This unexpected result was supported by long-term banding and was clearly linked to the species' extreme philopatric tendencies, emphasizing the importance of philopatry as an intrinsic barrier to gene flow. This implies that loss of a single colony could result in the loss of genetic variation, impairing the species' ability to adapt to threats in the long term. We anticipate that these findings will have a pivotal influence on seabird research and population management, focusing attention below the species level of taxonomic organization.

Synergistic Ground and Orbital Observations of Iron Oxides on Mt. Sharp and Vera Rubin Ridge.

Visible/short-wave infrared spectral data from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) show absorptions attributed to hematite at Vera Rubin ridge (VRR), a topographic feature on northwest Mt. Sharp. The goals of this study are to determine why absorptions caused by ferric iron are strongly visible from orbit at VRR and to improve interpretation of CRISM data throughout lower Mt. Sharp. These goals are achieved by analyzing coordinated CRISM and in situ spectral data along the Curiosity Mars rover's traverse. VRR bedrock within areas that have the deepest ferric absorptions in CRISM data also has the deepest ferric absorptions measured in situ. This suggests strong ferric absorptions are visible from orbit at VRR because of the unique spectral properties of VRR bedrock. Dust and mixing with basaltic sand additionally inhibit the ability to measure ferric absorptions in bedrock stratigraphically below VRR from orbit. There are two implications of these findings: (1) Ferric absorptions in CRISM data initially dismissed as noise could be real, and ferric phases are more widespread in lower Mt. Sharp than previously reported. (2) Patches with the deepest ferric absorptions in CRISM data are, like VRR, reflective of deeper absorptions in the bedrock. One model to explain this spectral variability is late-stage diagenetic fluids that changed the grain size of ferric phases, deepening absorptions. Curiosity's experience highlights the strengths of using CRISM data for spectral absorptions and associated mineral detections and the caveats in using these data for geologic interpretations and strategic path planning tools.

Feral cats do not play a major role in leptospirosis epidemiology on Reunion Island.

Although previous studies have reported Leptospira carriage in kidneys and urine of cats, the role of these animals in leptospirosis epidemiology remains poorly understood. Using molecular methods, we investigated Leptospira renal carriage in 172 feral cats from Reunion Island, an oceanic geographically isolated island located in the South West Indian Ocean. Only one out of the 172 analysed specimens tested positive for Leptospira DNA through quantitative real-time polymerase chain reaction. Using this positive sample, we could obtain sequences at three Leptospira loci (rrs2, lipL32 and lipL41) allowing to report for the first time Leptospira borgpetersenii naturally infecting cats. Comparisons with bacterial sequences from both acute human cases and animal reservoirs revealed similarities with Leptospira sequences previously reported on Reunion Island. However, the low prevalence (0.6%) reported herein does not support any major role of feral cats in leptospirosis epidemiology on Reunion Island, contrasting with results recently reported on another Indian Ocean Island, Christmas Island. The significance of these discrepancies is discussed.

Chemistry, mineralogy, and grain properties at Namib and High dunes, Bagnold dune field, Gale crater, Mars: A synthesis of Curiosity rover observations.

The Mars Science Laboratory Curiosity rover performed coordinated measurements to examine the textures and compositions of aeolian sands in the active Bagnold dune field. The Bagnold sands are rounded to subrounded, very fine to medium sized (~45-500 µm) with ≥6 distinct grain colors. In contrast to sands examined by Curiosity in a dust-covered, inactive bedform called Rocknest and soils at other landing sites, Bagnold sands are darker, less red, better sorted, have fewer silt-sized or smaller grains, and show no evidence for cohesion. Nevertheless, Bagnold mineralogy and Rocknest mineralogy are similar with plagioclase, olivine, and pyroxenes in similar proportions comprising >90% of crystalline phases, along with a substantial amorphous component (35% ± 15%). Yet Bagnold and Rocknest bulk chemistry differ. Bagnold sands are Si enriched relative to other soils at Gale crater, and H2O, S, and Cl are lower relative to all previously measured Martian soils and most Gale crater rocks. Mg, Ni, Fe, and Mn are enriched in the coarse-sieved fraction of Bagnold sands, corroborated by visible/near-infrared spectra that suggest enrichment of olivine. Collectively, patterns in major element chemistry and volatile release data indicate two distinctive volatile reservoirs in Martian soils: (1) amorphous components in the sand-sized fraction (represented by Bagnold) that are Si-enriched, hydroxylated alteration products and/or H2O- or OH-bearing impact or volcanic glasses and (2) amorphous components in the fine fraction (<40 µm; represented by Rocknest and other bright soils) that are Fe, S, and Cl enriched with low Si and adsorbed and structural H2O.

Spectrum of advice and curbside consultations of infectious diseases specialists.

OBJECTIVES: Curbside consultation (CC) of infectious diseases specialists for advice is very frequent but the corresponding workload has rarely been assessed. This activity is mostly oral (phone or direct contact) and poorly quantifiable because it is not charged. We had for aim to evaluate this activity in a French teaching hospital. METHODS: We recorded all CCs given during a 2.5-year period, from mid-2011 to the end of 2013. RESULTS: During the study period, 6789 CCs were recorded (2715 per year), or slightly more than 10 per day. These CCs were divided in 676 travel recommendations and 6113 for other reasons. They were mostly given by phone (77.4%). Most demands came from our hospital (61.4%), followed by community family physicians and specialist (27.1%), other local hospitals (6.5%) and clinics (4.3%). All the departments in our hospital consulted us for advice at least once and answers were mainly given by phone (70.1%) and at bedside (30.5%). The answers were principally advice (50.8%), modification of antibiotic prescription (22.9%), initiation of antibiotic course (14.8%), maintaining the same treatment (6.2%), and stopping antibiotics (4.3%). CCs accounted for 20% of clinical work for 1 physician. If the CCs in our hospital had been paid, our department would have received an additional 77,000€ in revenue. CONCLUSION: This curbside activity is very important and time-consuming for infectious diseases specialists, but it is currently not acknowledged or rewarded.

Campylobacter fetus infections.

BACKGROUND: Campylobacter fetus infections usually occur in immunodepressed patients or patients presenting with diabetes mellitus or cancer. They rarely cause diarrhea but frequently cause bacteremia or vascular diseases. The therapeutic management is not well codified and fluoroquinolone resistance is continuously increasing. METHODS: We conducted a retrospective study of C. fetus infections from January 2007 to August 2013 at the Limoges teaching hospital. The infections were defined by at least 1 bacteriological sample positive for C. fetus. RESULTS: Twenty patients were included (15 men), with an average age of 73 years (43-91). Sixteen presented with cancer, 12 with solid cancer including 9 of the urinary tract, and 9 patients with hematologic diseases. Five patients presented with diabetes mellitus, 9 with isolated bacteremia, 3 with cellulitis, and 3 with septic arthritis. The diagnosis was made by blood cultures for 17 patients. Twenty percent of the isolates were resistant to amoxicillin and 30% to fluoroquinolones. The therapeutic regimens and the treatment duration were quite different. The outcome was unfavorable for 3 patients whose implanted port had not been removed and 1 with subdural hematoma infection. 1 patient died. CONCLUSIONS: C. fetus infection occurs in case of underlying diseases, most frequently promoting urinary tract cancer. Fluoroquinolones must not be used without susceptibility testing and catheters should be removed.

Soil diversity and hydration as observed by ChemCam at Gale crater, Mars.

The ChemCam instrument, which provides insight into martian soil chemistry at the submillimeter scale, identified two principal soil types along the Curiosity rover traverse: a fine-grained mafic type and a locally derived, coarse-grained felsic type. The mafic soil component is representative of widespread martian soils and is similar in composition to the martian dust. It possesses a ubiquitous hydrogen signature in ChemCam spectra, corresponding to the hydration of the amorphous phases found in the soil by the CheMin instrument. This hydration likely accounts for an important fraction of the global hydration of the surface seen by previous orbital measurements. ChemCam analyses did not reveal any significant exchange of water vapor between the regolith and the atmosphere. These observations provide constraints on the nature of the amorphous phases and their hydration.

[Community-acquired meningitis due to methicillin susceptible Staphylococcus aureus]. / Méningites communautaires à Staphylococcus aureus méticilline sensible.

UNLABELLED: Meningitis due to Staphylococcus aureus is infrequent. MRSA is mainly found after neurosurgery, but MSSA may be involved in community-acquired meningitis. However, this kind of infection is not widely reported, despite its severity. METHODS: We describe the characteristics of five patients hospitalized in our ward over a period of 18 months who presented with community-acquired meningitis due to MSSA. RESULTS: The patients were three men and two women with a mean age of 62 years. One patient was immunosuppressed. Neurological signs were present at the onset for only two patients. In all cases, there were extraneurological localizations of the infection, mainly in bones (spondylodiscitis, epidural abscess, arthritis) but also lung infection. Three patients with meningeal inflammation also presented with confusion. CSF analysis revealed less than 950 white blood cells, hyper-CSF-proteins, and hypo-CSF-glucose. Bacteraemia was present in all patients. The source of infection was never determined. The evolution was good for all patients with a prolonged antibiotic course. The analysis of genetic determinants for three strains revealed the presence of TSST-1 which could account for the severity of the disease. CONCLUSION: Community-acquired MSSA meningitis is a serious infection, occurring in patients without risk factors. Hematogenous dissemination leads to multiple tissue infection. A long course of antibiotics, with high doses, is needed to treat meningitis but also extraneurological localizations. The role of TSST-1 needs to be confirmed in other patients.

Global mineralogical and aqueous mars history derived from OMEGA/Mars Express data.

Global mineralogical mapping of Mars by the Observatoire pour la Mineralogie, l'Eau, les Glaces et l'Activité (OMEGA) instrument on the European Space Agency's Mars Express spacecraft provides new information on Mars' geological and climatic history. Phyllosilicates formed by aqueous alteration very early in the planet's history (the "phyllocian" era) are found in the oldest terrains; sulfates were formed in a second era (the "theiikian" era) in an acidic environment. Beginning about 3.5 billion years ago, the last era (the "siderikian") is dominated by the formation of anhydrous ferric oxides in a slow superficial weathering, without liquid water playing a major role across the planet.

Phyllosilicates on Mars and implications for early martian climate.

The recent identification of large deposits of sulphates by remote sensing and in situ observations has been considered evidence of the past presence of liquid water on Mars. Here we report the unambiguous detection of diverse phyllosilicates, a family of aqueous alteration products, on the basis of observations by the OMEGA imaging spectrometer on board the Mars Express spacecraft. These minerals are mainly associated with Noachian outcrops, which is consistent with an early active hydrological system, sustaining the long-term contact of igneous minerals with liquid water. We infer that the two main families of hydrated alteration products detected-phyllosilicates and sulphates--result from different formation processes. These occurred during two distinct climatic episodes: an early Noachian Mars, resulting in the formation of hydrated silicates, followed by a more acidic environment, in which sulphates formed.

[The homeopathy or the myth of pure experience]. / L'homéopathie ou le mythe de l'expérience pure.

Hahnemann and homeopaths have always hold that the origine of homeopathy was essentially experimental. The Hippocrate's method of observation, the experience with quinquina carried out by Hahnemann in 1790, and furthermore a similar experimental thought than the C. Bernard's one, are constantly put forward. The alchemist origins of homeopathy, in particular Paracelse, that old authors had found, have been scathingly denied. It stands yet to reason that the rôle of the paracelsian philosophy, through the german philosophy at the Hahnemann's time and the medical vitalism at its acme at that time, was crucial. Nevertheless, the direct part of contemporary physicians, specially english ones, as Nugent, J. Hunter and Cullen has been disregarded. Hahnemann, proudly, said nothing about his most important springs. The history of his ideas, the theorical and conceptual problems involved by the principle of similitude and not only the infinitesimality, show that homeopathy arises, not so much from experience as from theoretical ideas, and mind of system so current before C. Bernard. It can be easily showed that C. Bernard's epistemology, which is prevailing in biology today, is a logical obstacle to homeopathy.

Copernicus: a regional probe of the lunar interior.

Earth-based telescopic spectral imaging techniques were used to document the spatial distribution of crater materials within the large lunar crater Copernicus at the subkilometer scale on the basis of spectral ultraviolet-visible-near-infrared characteristics. The proposed spectral mixing analysis leads to a first-order mapping of the impact melt material within the crater. Olivine was detected not only within the three central peaks but also along a significant portion of the crater rim. Consideration of an olivine-bearing end-member in the mixing model emphasizes the overall morphological pattern of the rim and wall terraces in the associated fraction image. The identification of widely exposed olivine units supports the idea that the lower crust and possibly the lunar mantle itself are regionally at shallow depth.

Hahnemann et les animalcules / Hahnemann and microorganisms

Hahnemann a remarquablement anticipe l'idee qu'il existait des amimalcules extremement petits, et specifiques, a l'origine des maladies "miasmatiques", contagieuses. Il a emis cette hypothese principalement dans le cas de deux maladies particulieres, les croutes de lait des 1795 et le cholera en 1831. Il l'a generalisee dans la deuxieme edition des maladies chroniques en 1835. Par la, il se distingue de ses soi-disant precurseurs, de la plupart des medecins de son temps, et s'est meme revele beaucoup plus perspicace que des savants reputes bien posterieurs. Adepte de la theorie nerveuse, il n'a cependant pas evite l'erreur de n'admettre que tres rarement la penetration des miasmes a l'interieur de l'organisme, et est victime de prejuges philosophiques

Quelques remarques historiques suplementaires sur Hahnemann et l'homeopathie / Some historical supplementary notes about Hahnemann and homeopathie

Dans cet article nous corrigeons certaines des erreurs que nous avons faites auparavant, et nous apportons d'autres elements historiques qui confirment, contrairement a ce qu'ont affirme la plupart des auteurs, qu'Hahnemann avait rencontre beaucoup de ses idees theoriques fondamentales avant son experience "princeps" avec le quinquina. Nous le montrons meme pour le principe des doses infinitesimales. Cependant, on peut voir clairement qu'il n'a pas erige d'emblee ces idees en principes formant la base d'un systeme. Dans ce champ theorique Hahnemann a parcouru de longs meandres, jalonnes d'experiences a l'interpretation assez delicate et pas toujours concrdantes, avant de selectionner et de determiner de facon relativement stable les fondements de son edifice

Paracelse, Nugent et Boyle, le "Tria Prima" d'Hahnemann / Paracelse, Nugent and Boyle, the "Tria Prima" of Hahnemann

Cet article nous permettra de conclure les sources de l'homeopathie, a la lumiere de celles que nous avons decouvertes. Nous sommes en mesure, maintenant, de demontrer que Paracelse a bien joue un role dans l'etablissement de la doctrine homeopathique. Cependant, nous pouvons egalement prouver que cette influence n'a pas ete aussi predominante qu'on l'a generalement dit, et, manifestement, d'autres sources ont ete tres importantes. La demarche d'Hahnemann peut, ainsi, nous apparaitre plus scientifique que la totalite de sa doctrine autoriserait a le penser. Il n'a pu se preserver de certaines considerations theoriques anciennes et d'une interpretation philosophique des faits, qui devaient susciter legitimement des controverses multiples et prolongees jusqu'a aujourd'hui