Les horloges publiques : un aspect méconnu du mécénat du duc Jean de Berry

Dans la France du bas Moyen Age, l’horlogerie restait une technologie au service de la grande aristocratie qui protégeait alors les rares horlogers comme elle le faisait avec ses architectes, peintres et sculpteurs. Le grand mécène Jean de Berry (1340-1416) participa lui aussi à ce phénomène et notamment par la multiplication des tours d’horloge en place publique. Beaucoup reste à dire sur cet aspect méconnu de sa contribution à l’art. À travers les cas bien documentés des deux horloges publiques qu’il installa à Bourges et Poitiers, nous sommes en mesure de percevoir – au-delà de la prouesse technique – toute la portée sociale et politique de ces programmes conjuguant les volontés communes de Jean de Berry et communautés urbaines.In France during the late middle ages, horlogery was still a technology for the high aristocrats which protected the rare watchmakers as they did with their architects, painters and sculptors. The great patron Jean de Berry (1340-1416) also took part in this kind of programs and especially the multiplication of clock towers in the public yard. Much could be said about this little known aspect of his contribution to art. Throught tow examples well documened of clock towers that he built in Bourges and Poitiers, we are able to perceive – beyond the technical prowess – all the social and political impact of these programs witch combines the common wishes of Jean de Berry and urban communities.Im Spätmittelalter ist die Uhrenfabrik in Frankreich eine Technologie, wobei die Aristokratie eine wichtige Rolle spielte. Dadurch wurden die Uhrmacher, ähnlich zu den Architekten, den Malern und den Bildhauern unterestützt. Der berühmte Jean de Berry ließ auch viele öffentliche Turmuhren errichten. Vieles ist noch im Hinblick auf diesen unbekannten Aspekt seiner Aufträge zu erforschen. Zwei gut dokumentierte Beispiele aus Bourges und aus Poitiers veranschaulichen nicht nur die technische Spitzenleistung von Turmuhren, sondern auch die gesellschaftliche und politische Bedeutung dieser Werke, die sowohl für Jean de Berry, als auch für die städtischen Gemeinschaften von Interesse waren

La maîtrise d’ouvrage de Jean de France, duc de Berry (1340-1416). Reconstitution et analyse critique d’une documentation dispersée

Une étude approfondie des archives de Jean de Berry peut être d’un grand secours pour appréhender le problème de sa maîtrise d’ouvrage, vaste sujet qui ne peut être simplement limité aux prestigieuses résidences – le château de Mehun-sur-Yèvre par exemple – ou à l’ambitieux programme politique de la Sainte-Chapelle de Bourges. L’étendue et la variété des chantiers exigèrent la mobilisation de tous : du simple châtelain aux plus proches officiers du prince, des artisans locaux aux maîtres d’œuvre les plus qualifiés. Cette fusion de la construction et l’entretien du bâti dans l’action du gouvernement princier explique le caractère hétéroclite, dispersé et souvent très lacunaire des archives.A closed study of John of Berry’s archives can be usefull to understand his building mastery: a vast subject that cannot be limited to the most famous residences, e.g. the castle of Mehun-sur-Yèvre, or the ambitious political building scheme for the Sainte-Chapelle at Bourges. The number and diverse character of each building project required the mobilisation of every available man, from the modest castellan to the most important court officer, from the local craftsman to the most skilled and qualified stone mason. The construction of a building and its ensuing maintenance were closely linked. Since they formed part of the ducal administation, their interconnection explains the character of the documentary archive which is irregular, disorganised and incomplete

Diagenetic Mineralogy at Gale Crater, Mars

Three years into exploration of sediments in Gale crater on Mars, the Mars Science Laboratory rover Curiosity has provided data on several modes and episodes of diagenetic mineral formation. Curiosity determines mineralogy principally by X-ray diffraction (XRD), but with supporting data from thermal-release profiles of volatiles, bulk chemistry, passive spectroscopy, and laser-induced breakdown spectra of targeted spots. Mudstones at Yellowknife Bay, within the landing ellipse, contain approximately 20% phyllosilicate that we interpret as authigenic smectite formed by basalt weathering in relatively dilute water, with associated formation of authigenic magnetite as in experiments by Tosca and Hurowitz [Goldschmidt 2014]. Varied interlayer spacing of the smectite, collapsed at approximately 10 A or expanded at approximately 13.2 A, is evidence of localized diagenesis that may include partial intercalation of metal-hydroxyl groups in the approximately 13.2 A material. Subsequent sampling of stratigraphically higher Windjana sandstone revealed sediment with multiple sources, possible concentration of detrital magnetite, and minimal abundance of diagenetic minerals. Most recent sampling has been of lower strata at Mount Sharp, where diagenesis is widespread and varied. Here XRD shows that hematite first becomes abundant and products of diagenesis include jarosite and cristobalite. In addition, bulk chemistry identifies Mg-sulfate concretions that may be amorphous or crystalline. Throughout Curiosity's traverse, later diagenetic fractures (and rarer nodules) of mm to dm scale are common and surprisingly constant and simple in Ca-sulfate composition. Other sulfates (Mg,Fe) appear to be absent in this later diagenetic cycle, and circumneutral solutions are indicated. Equally surprising is the rarity of gypsum and common occurrence of bassanite and anhydrite. Bassanite, rare on Earth, plays a major role at this location on Mars. Dehydration of gypsum to bassanite in the dry atmosphere of Mars has been proposed but considered unlikely based on lab studies of dehydration kinetics in powdered samples. Dehydration is even less likely for bulk vein samples, as lab data show dehydration rates one to two orders of magnitude slower in bulk samples than in powders. On Mars, exposure ages of 100 Ma or more may be a significant factor in dehydration of hydrous phases

Hydrogen Variability in the Murray Formation, Gale Crater, Mars

The Mars Science Laboratory (MSL) Curiosity rover is exploring the Murray formation, a sequence of heterolithic mudstones and sandstones recording fluvial deltaic and lake deposits that comprise over 350 m of sedimentary strata within Gale crater. We examine >4,500 Murray formation bedrock points, employing recent laboratory calibrations for ChemCam laser‐induced breakdown spectroscopy H measurements at millimeter scale. Bedrock in the Murray formation has an interquartile range of 2.3–3.1 wt.% H₂O, similar to measurements using the Dynamic Albedo of Neutrons and Sample Analysis at Mars instruments. However, specific stratigraphic intervals include high H targets (6–18 wt.% H₂O) correlated with Si, Mg, Ca, Mn, or Fe, indicating units with opal, hydrated Mg sulfates, hydrated Ca sulfates, Mn‐enriched units, and akageneite or other iron oxyhydroxides, respectively. One stratigraphic interval with higher hydrogen is the Sutton Island unit and Blunts Point unit contact, where higher hydrogen is associated with Fe‐rich, Ca‐rich, and Mg‐rich points. A second interval with higher hydrogen occurs in the Vera Rubin ridge portion of the Murray formation, where higher hydrogen is associated with Fe‐rich, Ca‐rich, and Si‐rich points. We also observe trends in the H signal with grain size, separate from chemical variation, whereby coarser‐grained rocks have higher hydrogen. Variability in the hydrogen content of rocks points to a history of water‐rock interaction at Gale crater that included changes in lake water chemistry during Murray formation deposition and multiple subsequent groundwater episodes

Hydrogen Variability in the Murray Formation, Gale Crater, Mars

The Mars Science Laboratory (MSL) Curiosity rover is exploring the Murray formation, a sequence of heterolithic mudstones and sandstones recording fluvial deltaic and lake deposits that comprise over 350 m of sedimentary strata within Gale crater. We examine >4,500 Murray formation bedrock points, employing recent laboratory calibrations for ChemCam laser‐induced breakdown spectroscopy H measurements at millimeter scale. Bedrock in the Murray formation has an interquartile range of 2.3–3.1 wt.% H₂O, similar to measurements using the Dynamic Albedo of Neutrons and Sample Analysis at Mars instruments. However, specific stratigraphic intervals include high H targets (6–18 wt.% H₂O) correlated with Si, Mg, Ca, Mn, or Fe, indicating units with opal, hydrated Mg sulfates, hydrated Ca sulfates, Mn‐enriched units, and akageneite or other iron oxyhydroxides, respectively. One stratigraphic interval with higher hydrogen is the Sutton Island unit and Blunts Point unit contact, where higher hydrogen is associated with Fe‐rich, Ca‐rich, and Mg‐rich points. A second interval with higher hydrogen occurs in the Vera Rubin ridge portion of the Murray formation, where higher hydrogen is associated with Fe‐rich, Ca‐rich, and Si‐rich points. We also observe trends in the H signal with grain size, separate from chemical variation, whereby coarser‐grained rocks have higher hydrogen. Variability in the hydrogen content of rocks points to a history of water‐rock interaction at Gale crater that included changes in lake water chemistry during Murray formation deposition and multiple subsequent groundwater episodes

In Situ Analysis of Opal in Gale Crater, Mars

Silica enrichments resulting in up to ~90 wt% SiO2 have been observed by the Curiosity rover's instruments in Gale crater, Mars, within the Murray and Stimson formations. Samples acquired by the rover drill revealed a significant abundance of an X‐ray amorphous silica phase. Laser‐induced breakdown spectroscopy (LIBS) highlights an overall correlation of the hydrogen signal with silica content for these Si‐enriched targets. The increased hydration of the high‐silica rocks compared to the surrounding bedrock is also confirmed by active neutron spectroscopy. Laboratory LIBS experiments have been performed to calibrate the hydrogen signal and show that the correlation observed on Mars is consistent with a silica phase containing on average 6.3 ± 1.4 wt% water. X‐ray diffraction and LIBS measurements indicate that opal‐A, amorphous hydrated silica, is the most likely phase containing this water in the rocks. Pyrolysis experiments were also performed on drilled samples by the Sample Analysis at Mars (SAM) instrument to measure volatile content, but the data suggests that most of the water was released during handling prior to pyrolysis. The inferred low‐temperature release of water helps constrain the nature of the opal. Given the geological context and the spatial association with other phases such as calcium sulfates, the opal was likely formed from multiple diagenetic fluid events and possibly represents the latest significant water‐rock interaction in these sedimentary rocks

In situ detection of boron by ChemCam on Mars

We report the first in situ detection of boron on Mars. Boron has been detected in Gale crater at levels Curiosity rover ChemCam instrument in calcium-sulfate-filled fractures, which formed in a late-stage groundwater circulating mainly in phyllosilicate-rich bedrock interpreted as lacustrine in origin. We consider two main groundwater-driven hypotheses to explain the presence of boron in the veins: leaching of borates out of bedrock or the redistribution of borate by dissolution of borate-bearing evaporite deposits. Our results suggest that an evaporation mechanism is most likely, implying that Gale groundwaters were mildly alkaline. On Earth, boron may be a necessary component for the origin of life; on Mars, its presence suggests that subsurface groundwater conditions could have supported prebiotic chemical reactions if organics were also present and provides additional support for the past habitability of Gale crater

An interval of high salinity in ancient Gale crater lake on Mars

Precipitated minerals, including salts, are primary tracers of atmospheric conditions and water chemistry in lake basins. Ongoing in situ exploration by the Curiosity rover of Hesperian (around 3.3–3.7 Gyr old) sedimentary rocks within Gale crater on Mars has revealed clay-bearing fluvio-lacustrine deposits with sporadic occurrences of sulfate minerals, primarily as late-stage diagenetic veins and concretions. Here we report bulk enrichments, disseminated in the bedrock, of 30–50 wt% calcium sulfate intermittently over about 150 m of stratigraphy, and of 26–36 wt% hydrated magnesium sulfate within a thinner section of strata. We use geochemical analysis, primarily from the ChemCam laser-induced breakdown spectrometer, combined with results from other rover instruments, to characterize the enrichments and their lithology. The deposits are consistent with early diagenetic, pre-compaction salt precipitation from brines concentrated by evaporation, including magnesium sulfate-rich brines from extreme evaporative concentration. This saline interval represents a substantial hydrological perturbation of the lake basin, which may reflect variations in Mars’ obliquity and orbital parameters. Our findings support stepwise changes in Martian climate during the Hesperian, leading to more arid and sulfate-dominated environments as previously inferred from orbital observations

Planetary Candidates Observed by Kepler, III: Analysis of the First 16 Months of Data

New transiting planet candidates are identified in sixteen months (May 2009 - September 2010) of data from the Kepler spacecraft. Nearly five thousand periodic transit-like signals are vetted against astrophysical and instrumental false positives yielding 1,091 viable new planet candidates, bringing the total count up to over 2,300. Improved vetting metrics are employed, contributing to higher catalog reliability. Most notable is the noise-weighted robust averaging of multi-quarter photo-center offsets derived from difference image analysis which identifies likely background eclipsing binaries. Twenty-two months of photometry are used for the purpose of characterizing each of the new candidates. Ephemerides (transit epoch, T_0, and orbital period, P) are tabulated as well as the products of light curve modeling: reduced radius (Rp/R*), reduced semi-major axis (d/R*), and impact parameter (b). The largest fractional increases are seen for the smallest planet candidates (197% for candidates smaller than 2Re compared to 52% for candidates larger than 2Re) and those at longer orbital periods (123% for candidates outside of 50-day orbits versus 85% for candidates inside of 50-day orbits). The gains are larger than expected from increasing the observing window from thirteen months (Quarter 1-- Quarter 5) to sixteen months (Quarter 1 -- Quarter 6). This demonstrates the benefit of continued development of pipeline analysis software. The fraction of all host stars with multiple candidates has grown from 17% to 20%, and the paucity of short-period giant planets in multiple systems is still evident. The progression toward smaller planets at longer orbital periods with each new catalog release suggests that Earth-size planets in the Habitable Zone are forthcoming if, indeed, such planets are abundant.Comment: Submitted to ApJS. Machine-readable tables are available at http://kepler.nasa.gov, http://archive.stsci.edu/kepler/results.html, and the NASA Exoplanet Archiv

Code Llama: Open Foundation Models for Code

We release Code Llama, a family of large language models for code based on Llama 2 providing state-of-the-art performance among open models, infilling capabilities, support for large input contexts, and zero-shot instruction following ability for programming tasks. We provide multiple flavors to cover a wide range of applications: foundation models (Code Llama), Python specializations (Code Llama - Python), and instruction-following models (Code Llama - Instruct) with 7B, 13B and 34B parameters each. All models are trained on sequences of 16k tokens and show improvements on inputs with up to 100k tokens. 7B and 13B Code Llama and Code Llama - Instruct variants support infilling based on surrounding content. Code Llama reaches state-of-the-art performance among open models on several code benchmarks, with scores of up to 53% and 55% on HumanEval and MBPP, respectively. Notably, Code Llama - Python 7B outperforms Llama 2 70B on HumanEval and MBPP, and all our models outperform every other publicly available model on MultiPL-E. We release Code Llama under a permissive license that allows for both research and commercial use