dataesr/scientific-paragraphs-categorization huggingface dataset:
Included are ultraviolet (UV) sensors, a radiometer and a set of eight thermistors to measure the experimental temperatures. The sensor data are stored on board and retrieved after landing. The temperature profile of the experiments is selectable. A non-controlled mode can be chosen with temperatures freely oscillating between ≤ -20 and ≥ +10°C, in synchronization with the alternating periods of solar illumination and shadowing in orbit. Alternatively, by using electrical heaters and thermal blankets, a stable temperature can be provided with a fixed set point in the 10-25°C range for experiments in the bottom half of Biopan. Organic molecules, bacterial spores and vegetative cells, archaea, plant seeds, lichens, and tardigrades have been exposed in Biopan to a combination of solar UV, space vacuum, space radiation, wide temperature fluctuations, and weightlessness.
1984a (Horneck et al. , 1984b)). The EXPOSE-R facility, named after its final destination on the Russian external platform is secured to the outer hull of the Service Module Zvezda of the ISS as part of the Russian Segment. This external platform, called URM-D, provides mechanical, electrical, and data interfaces. EXPOSE-R accommodated 10 biological and biochemical experiments, mounted in 4 cavities, called compartments, in each of the three removable containers, called trays (Fig. 9 ). These trays can also be exchanged when EXPOSE-R is mounted on the URM-D and exposed to the open space, providing increased programmatic flexibility. Attachment, retrieval, and exchange take place by Extra Vehicular Activities (EVA) of the ISS crew  (Rabbow et al. 2015b ). The first EXPOSE-R and its experiment inserts were launched on flight 31P on November 26, 2008 on an unmanned PROGRESS cargo ship on a SOYUZ launcher from Baikonur, Kazakhstan.
Experiment Sequence Tests and Science Verification Tests (EST, SVT) were the final ground tests and rehearsal for flight: experiments were accommodated as for flight in identical ground trays to verify the whole series of procedures. During the ground tests, the experiments were exposed to space parameters similar to those expected during the mission: high and low temperatures and temperatures repeatedly cycling through the freezing point 0°C, short wavelength polychromatic UV down to 200 nm, and vacuum, provided individually or in combination. At the same time as the EXPOSE-E and EXPOSE-R/-R2 space missions, an identical set of flight trays fully equipped with samples was exposed in the PSI at DLR as in space, as far as technically feasible and according to the data available. The space EXPOSE facilities measured environmental data every 10 seconds, such as temperature and visible or UV photons reaching the facility, as well as housekeeping and functionality data of the facility.
While EXPOSE-E data were received by telemetry regularly, EXPOSE-R data were downloaded from the ISS on PCMCIA cards and by telemetry every few months. The two past missions EXPOSE-R and EXPOSE-E were an overall success, although some environmental data were missing due to a variety of reasons from both missions. The results of the EXPOSE-E are published in the Issue No 5, Volume 12 of Astrobiology, published in May 2012. The results of the EXPOSE-R mission and experiment results are published in Issue 1, Volume 14 of the Journal of Astrobiology, published in January 2015. A list of all the experiments conducted on EXPOSE facilities is shown in Table  4.
O/OREOS Nanosatellite The NASA 3U cubesat Organism/Organic Exposure to Orbital Stresses (O/OREOS) was launched in November 2010 to undertake a 6-month mission to demonstrate astrobiological measurement technologies. After more than five years, the nanosatellite is still operational in LEO above 600 km and is used for educational purposes, including routine radio telemetry of spacecraft health and status; science data are no longer downlinked. O/OREOS achieved its overall goal to utilize autonomous instrumentation and sensors for the in-situ investigation of microbes and biomarkers in space conditions using a free-flying nanosatellite. Its launch to a high-inclination (72°), 650-km Earth orbit aboard a US Air Force Minotaur IV rocket from Kodiak, Alaska provided conditions where in-orbit solar and galactic particle radiation doses-much of it from significant durations spent in the inner Van Allen Belt-exceed ISS dose rates by approximately a factor of fifteen.
The O/OREOS 3U satellite (3 dm 3 volume total) consists of a control bus and two high-capability science payloads, each contained in 1U cubesat module (Fig. 12 ). Fig. 12  NASA Ames's O/OREOS triple-cubesat (with the de-orbit mechanism deployed) achieved full mission success in May 2011; the first science results from both astrobiology payloads have been reported  (Cook et al. 2014; Mattioda et al. 2012; Nicholson et al. 2011). Credit: NASA ARC The SESLO experiment collected data on the survival and metabolic activity for microorganisms three times during the 6-month mission. This payload consists of three "bioblock" modules, each with twelve 75-μL sample wells connected by microfluidic channels and valves that allow the introduction of germination/growth media. Prior to spacecraft integration and flight, bacterial cells were dried onto the walls of the sample wells and the bioblocks were sealed using a gas-permeable membrane.
3. 1). Integrated optics enable the use of the Sun as the light source for both sample electromagnetic radiation exposure and sample spectroscopic measurement. The SEVO payload returned spectral data sets over 17 months of space exposure  (Mattioda et al. 2012). Results are summarized below in "O/OREOS Results" (Sect. 3. 2. 3. e). The O/OREOS mission, including launch, successful operation of both payloads, and download of collected mission data, achieved full success in May 2011  (Ehrenfreund et al. 2014; Kitts et al. 2011). The SESLO and SEVO experiments serve as precursors for experiments on the ISS, future free-flyers, and planetary surface exposure facilities. Future flight opportunities can leverage this tested and proven triple-cubesat configuration, particularly.
OREOcube will be installed as an external exposure facility on the ISS under ESA's European Program for Life and Physical Sciences in Space (ELIPS) to study the evolution of organic and prebiotic materials in space. OREOcube will consist of two SEVO cubes (Fig. 13 ) and can record daily changes in ultraviolet and visible light absorption spectra of organic compounds, revealing the consequences of their exposure to solar UV and visible light and space ionizing radiation. The advantages over a free-flyer experiment are that data can be downloaded from the ISS more effectively and more frequently with on-board data averaging and storage capability using a standard power-and-command interface. Additionally, the payload or its sample carousels can be retrieved to enable additional sample-and photoproduct-characterization experiments in the laboratory on Earth.
2014). Possible implementation scenarios for OREOcube consider attachment on either the Columbus module, the JAXA-KIBO facility, or the NanoRacks External Payload Platform (NREP). The last of these would require little modification of the SEVO cube-format payload in terms of additional hardware and add the benefit of already-available data and power connections. NanoRacks NREP was deployed outside the ISS in August 2016, while ORE-Ocube is schedule to be delivered to the ISS in the 2018 time frame. Recent plans at ESA also include integration of OREOcube in a newly designed and developed 'European Exposure Facility', which would be able to accommodate various space exposure experiments with the need for in-situ measurements.
Acknowledgements. References. Acknowledgements This work has been supported by  ESA , through a  Topical Team grant  from  2011  to 2016. We are grateful to  Oliver Angerer ,  Jason Hatton ,  René Demets  from  ESA  for their help and support. UPEC and LISA provided important administrative help ( Mireille Paul ,  Sabrina Hammache ,  Valérie Simard ,  Charlotte Laurent ,  Nicolas Vautrin ). Hervé Cottin  acknowledges support from  CNES  and  Labex ESEP  ( N°2 011-LABX-030 ). Kafila Saiagh  acknowledges support from  DIM ACAV (region Ile de France). Zita Martins  is funded by a  Royal Society University Research Fellowship  (grant  UF080820  and grant  UF130324 ). Pascale Ehrenfreund  and  Richard Quinn  acknowledge support from the  NASA Astrobiology Institute. Jean-Pierre de Vera acknowledges the Helmholtz-Gemeinschaft  for financial support through the  Helmholtz-Alliance Planetary Evolution  and  Life.
Daniela Billi  and  Silvano Onofri acknowledge Italian Space Agency (ASI)  for financial support of the projects  BIOMEX-Cyano, BOSS-Cyano, BIOMEX-MCF  and  E-GEM. Nathalie Carrasco  acknowledges the financial support of the  European Research Council  ( ERC Starting Grant PRIMCHEM , grant agreement  n°636829 ). Hirofumi Hashimoto ,  Shin-ichi Yokobori ,  Eiichi Imai ,  Issay Narumi  and the Tanpopo team are also warmly thanked. The two anonymous reviewers of this paper are warmly thanked for their detailed and constructive comments. Open Access  for this paper has been funded by  CNES.
Delafossite crystals are fascinating ternary oxides that have demonstrated transparent conductivity and ambipolar doping. Here we use a high-throughput approach based on density functional theory to find delafossite and related layered phases of composition ABX 2 , where A and B are elements of the periodic table, and X is a chalcogen (O, S, Se, and Te). From the 15 624 compounds studied in the trigonal delafossite prototype structure, 285 are within 50 meV/atom from the convex hull of stability. These compounds are further investigated using global structural prediction methods to obtain their lowest-energy crystal structure. We find 79 systems not present in the materials project database that are thermodynamically stable and crystallize in the delafossite or in closely related structures.
The cation A is usually a noble metal like Cu, Ag, Pd or Pt; the cation B is typically a transition or group 13 element or a rare earth species; finally, the anion X is usually oxygen, although few delafossites with other anions can be found in materials databases  [3] [4] [5]. The trigonal delafossite structure (space group 166) is shown in the left panel of Fig. 1. A polytype of this structure with hexagonal symmetry (space group 194) can be formed when two neighboring A layers are stacked with each layer rotated by 180° in relation to one another. If A belongs to the IA group, one often finds another closely related trigonal structure (space group 164) with a slightly different stacking and where the layers are closer (see right panel of Fig. 1 ). Due to the rather large range of possible stable configurations, it is not surprising that delafossites exhibit a significant richness in properties and potential applications.
They found that at 600 °C, the Mg-doped CuCrO 2 structure displayed an optical transmittance of only 63% in the visible range with, however, a conductivity of 1. 6 S cm -1. Another idea, again put forward by Hosono and co-workers  33  , is to replace oxygen with a chalcogen (S, Se, or Te) with more delocalized p orbitals. This has led to the synthesis of LaCuOS and LaCuOSe p-type oxides  34, 35. Unfortunately, these latter compounds have either a too low mobility (LaCuOS) or a too small band gap (LaCuOSe). However, this strategy looks appealing as the p states of the chalcogen atoms are usually higher and therefore make the compound more prone to be p-doped. Recent calculations suggest that this is the case for Ba(Cu, Ag) 2 (S, Se) 2 compounds  36. Going beyond simple empirical rules, experimental databases have been recently explored by performing high-throughput ab initio calculations  37, 38  to single out compounds with large band gaps (> 3 eV) and low effective masses.
We extend in fact our study to all ABX 2 compositions where A and B cover the periodic table from H to Bi (excluding the rare gases and the lanthanides) and X is a chalcogen (O, S, Se, and Te). This set contains 63 × 62 × 4 = 15624 compositions and includes the already known delafossites crystals. At this point, we take all A and B elements and do not make any bias towards non-toxic or abundant elements. Such filtering can however be easily performed a posteriori. We note that most research on delafossites is restricted to oxide materials. Also most of the systems known have X = O. For example, the materials project database  3  , contains 90 trigonal ABX 2 oxides (with space group 166) while only 23 sulfides, 10 selenides and 7 tellurides. It is unclear if this is because the delafossite structure prefers the highly electronegative oxygen, or if it simply reflects a bias against sulfides, selenides, and tellurides.
We then filter this list using a threshold of 50 meV/atom above the convex hull. This is a rather conservative threshold, that tries to minimize the number of false positives, but at the same time takes into account the errors in evaluating differences of PBE energies  44  and the possible reduction of the energy of formation related to small distortions of the lattice, native defects, temperature and disorder, etc. This also allows us to include in our list some experimentally known delafossite structures that exhibit (small) positive distances to the hull in our formalism, such as CuInO 2 (7 meV/atom). Within this threshold we find 285 compositions (109 oxides, 66 sulfides, 67 selenides, and 43 tellurides). We can find entries in the materials project database for 101 of the 285 compositions, namely for 72 oxides (including our predictions of ref.
39), 11 sulfides, 11 selenides, and 7 tellurides. Obviously, there are many more entries ABX 2 with X = O, S, Se, Te in the materials project database (463 in total at the time of writing), but most of these, such as, e. g. , the chalcopyrites, have atomic arrangements very different from the delafossites, and do not appear therefore as a result of our search. We could also find in literature some (unfortunatley incomplete) information on other compounds that are not part of the materials project database: MgNiO 2 , PdCrO 2 45,46 , PdRhO 2. The fact that we also identify these compounds as thermodynamically stable is another confirmation of the validity of our approach. It is quite interesting to compare at this stage these numbers. First, they indicate that there are probably many more stable ternary compounds than the ones known experimentally (or predicted theoretically and already present in the databases).
Second, we can see the strong experimental bias towards oxides in detriment of other chalcogenides. Up to now, we only know that the delafossite phase is stable (or almost) regarding the decomposition into other compounds. The following step in our investigation is to evaluate if the delafossite phase is indeed the ground-state structure, or if there exist other phases lower in energy. We combined two different approaches for all stoichiometries that did not already appear in the materials project database: (i) We tested a set of common prototype structures for the composition ABX 2 (see Table  1 ). This amounts to 28 further structural optimizations per composition. (ii) For each composition, we performed two independent structural prediction runs including 8 atoms (2 formula units) in the unit cell.
For these structures we finally calculate indirect and direct band gaps, magnetic moments per formula unit and hole effective masses whenever the system is non-metallic. Our results concerning all new structures, i. e. the ones not already present in the materials project database, are summarized in Tables 2, 3, 4, and 5. For completeness, we decided to also include the information concerning the phases reported in the literature but not present in the materials project database. These can be found in bold in the tables. All crystallographic information files are given as Supporting Information. We can observe that there are 79 delafossite systems that are stable (and 123 close to stability). The tables include 16 (10) new oxides, 40 (27) sulfides, 38 (25) selenides, and 29 (17) tellurides.
We will now discuss in detail our results separately for oxides, sulfides, selenides, and tellurides. ABO 2. Among the 3906 possible delafossite oxides (compatible with our selection of chemical elements) there are 93 phases that appear at least 25 meV/atom below the convex hull of stability. Of these, 77 can already be found in the materials project database 3 or in ref. 39. The remaining 16 compositions are reported in Table  2. All compounds with A = Pd, Pt, Hg, Tl, and Br crystallize in the delafossite structure with space group 166. The only exception is BrLaO 2 where the stacking is slightly changed, leading to a monoclinic ground-state (prototype of NaCuO 2 ) which is 14 meV/atom lower in energy than the trigonal delafossite phase. On the other hand, when A is an alkali or an alkali earth metal, the ground-state phase has the trigonal structure of TlScSe 2 (space group 166), that is very similar to the trigonal structure of AgBiS 2 (space group 164) shown in the right panel of Fig.
1. The crystals KInO 2 , RbInO 2 , RbRhO 2 , CsLaO 2 , HgMgO 2 , and BrLaO 2 are semiconductors with gaps between 3 and 4 eV, and not too large effective masses of around 2 m e (with the notable exception of RbRhO 2 ). We note that hole effective masses of 1~2 m e are not small in absolute terms, but they are comparable with those of CuAlO 2 and CuCrO 2. Among the metals, the compounds containing Ni and Cr are magnetic, with a total magnetization that can reach 3. 0 bohr magnetons for the ferromagnetic compound PdCrO 2. ABS 2. Among all the stable sulfides that we found in this work, only 10 compositions could be found in the materials project database 3. These are NaScS 2 , NaInS 2 , KCrS 2 , KLaS 2 , RbYS 2 , CsLaS 2 , AgBiS 2 , AuCrS 2 , TlBS 2 , and TlInS 2. All the other novel 40 compositions can be found in Table  3.
Many of the novel systems are semiconducting with indirect band gaps varying in the rather large range of 0. 7-3. 4 eV. Hole effective masses, as expected considering the more delocalized nature of S p states, are significantly lower than in oxides. We would like to point out materials like (K, Rb)YS 2 , composed of relatively abundant elements, with rather large band gaps of the same order of magnitude as the usual Cu delafossite TCOs, and with rather small hole effective masses (of the order of 1. ABSe 2. For the selenides ABSe 2 we find 48 phases below 25 meV/atom, 10 of which can be found in the materials project database. The results for the remaining 38 phases can be found in Table  4. For the compounds with a IA element in the 1a Wyckoff position we find that stable compounds tend to have larger alkalis (Rb, Cs) in detriment of the lighter ones (Na, K).
Compounds including Cr and Mn are magnetic, but AuCoSe 2 , BrNiSe 2 , and INiSe 2 are non-magnetic. ABTe 2. From the systems found in our search, there are only 7 ABTe 2 phases in the material project database. These structures are AgSbTe 2 , AgBiTe 2 , KLaTe 2 , KYTe 2 , TlSbTe 2 , TlScTe 2 and TlBiTe 2. Besides these known tellurides, we identify 29 new phases that are stable or very close to stability (see Table  5 ). As expected by the chemical similarity between Se and Te, the situation here is analogous to what was described for the Se systems. Perhaps the biggest difference regards the chalcogen in the Wyckoff position 1a. We find a series of Br and I metallic compounds with the 1b position occupied by a transition metal. Some of these systems, like BrPtTe 2 , are quite below the convex hull of stability, which, together with the overall consistency of the results, makes us believe that these exotic systems can be experimentally synthesized.
From the compositions that do not crystallize in the structures of Fig. 1  we have: HgVTe 2 , with displays distorted planes; BrIrTe 2 with has a different stacking; BrPdTe 2 with distorted Br layers; finally INiTe 2 and IPdTe 2 have a different stacking. The two compounds with Mn in the 1b position are ferromagnetic, but, more surprisingly, we also find that HgVTe 2 are TlTiTe 2 have a relatively small magnetic moment. For the semiconducting compounds there is also a further decrease of the magnitude of the gap with respect to the selenides. Gaps and hole effective masses. Finally, Fig. 3  is a scatter plot of the direct band gap and the average hole effective mass for all delafossite-like compounds within our window of stability. We include both the new systems found in this work, as well as the other compounds from the materials project database (such as CuAlO 2 , CuGaO 2 , RbYO 2 , AgYO 2 , etc.
At the end of this procedure, we could count 79 ternary systems not present in the materials project database that are thermodynamically stable (and therefore potentially synthesizable) and crystallize in the delafossite or in closely related structures. Among these new delafossites, 10 are oxides, 27 sulfides, 25 selenides and 17 tellurides. If we include also the new structures that are above the convex hull of stability within a threshold of 25 meV per atom, the number of new systems increases to 123. By calculating the band gaps and hole effective masses of these structures we identified few systems that could be better p-type transparent conducting materials than those already known. In particular, AgYS 2 , with an HSE band gap of 3. 16 eV and a hole effective mass of 0. 71 m e , is probably the best system that emerged from this study.
It is true that this number could be quite reduced by eliminating compositions on the basis of empirical rules based on oxidation states or the radius of the A, B, and X elements. However, we decided not to follow this path in order to allow for delafossites that do not conform to our intuition. For each one of these structures we optimized the geometry and calculated the total energy. This was done within ab initio density functional theory as implemented in the computer code VASP  60, 61. All parameters were set to guarantee compatibility with the data available in the materials project database 3 and open quantum materials database  4. We used the PAW 62 datasets of version 5. 2 with a cutoff of 520 eV and Γ -centered k-point grids, as dense as required to ensure an accuracy of 2 meV/atom in the total energy.
In this case, the thermodynamic quantity of interest is the total energy. Fortunately, it is no longer necessary to calculate the total energy of all possible reservoir compounds, as this information is already available in excellent public databases, such as the materials project 3 , open quantum materials database  4  , and the ab-initio electronic structure library aflowlib  5. We chose to use the materials project database for our reference energies, and to determine the distances to the convex hull of stability with pymatgen  65. The materials project database includes most of the experimentally known inorganic crystals that are present in the ICSD database  66, 67  and an increasing number of theoretically predicted phases, including those proposed in ref. 39. Note that, as we only use the compounds included in the database to build the convex hull, new materials will appear with negative distances to the hull.
16S rRNA Sequencing Analysis The mixtures of 16S rRNA gene amplicons were generated using a 341F/815R primer set, as previously described by  Dowd et al. (2008) , and were sequenced by the MiSeq Illumina (paired-end 2 × 300 bp) platform of the Molecular Research Laboratory (Texas, USA). Raw data were analyzed using QIIME 1. 9. 1 as described by  Caporaso et al. (2010). Briefly, the raw reads were  checked for adapter, chimera and low quality sequences. The trimmed reads were clustered into operational taxonomic units (OTUs) using a 97% sequence identity threshold with UCLUST  (Edgar, 2010). The taxonomic assignment was performed by UCLUST taxonomy. Similarity search by BLAST algorithm  (Altschul et al. , 1990)  against non-redundant nr nucleotide database was performed for OTU representative sequences.