The Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals (SHERLOC) instrument onboard the Mars 2020 Perseverance rover detected so far some of the most intense fluorescence signals in association with sulfates analyzing abraded patches of rocks at Jezero crater, Mars. To assess the plausibility of an organic origin of these signals, it is key to understand if organics can survive exposure to ambient Martian UV after exposure by the Perseverance abrasion tool and prior to analysis by SHERLOC. In this work, we investigated the stability of organo-sulfate assemblages under Martian-like UV irradiation and we observed that the spectroscopic features of phthalic and mellitic acid embedded into hydrated magnesium sulfate do not change for UV exposures corresponding to at least 48 Martian sols and, thus, should still be detectable in fluorescence when the SHERLOC analysis takes place, thanks to the photoprotective properties of magnesium sulfate. In addition, different photoproduct bands diagnostic of the parent carboxylic acid molecules could be observed. The photoprotective behavior of hydrated magnesium sulfate corroborates the hypothesis that sulfates might have played a key role in the preservation of organics on Mars, and that the fluorescence signals detected by SHERLOC in association with sulfates could potentially arise from organic compounds.

The Mars 2020 Perseverance rover has explored fluvio-lacustrine sedimentary rocks within Jezero crater. Prior work showed that igneous crater floor S & eacute;& iacute;tah and M & aacute;az formations have mafic mineralogy with alteration phases that indicate multiple episodes of aqueous alteration. In this work, we extend the analyses of hydration to targets in the Jezero western fan delta, using data from the SHERLOC (Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals) Raman spectrometer. Spectral features, for example, sulfate and hydration peak positions and shapes, vary within, and across the crater floor and western fan. The proportion of targets with hydration associated with sulfates was approximately equal in the crater floor and the western fan. All hydrated targets in the crater floor and upper fan showed bimodal hydration peaks at similar to 3,200 and similar to 3,400 cm(-1). The sulfate symmetric stretch at similar to 1,000 cm(-1) coupled with a hydration peak at similar to 3,400 cm(-1) indicate that MgSO4nH(2)O (2 < n <= 5) is a likely hydration carrier phase in all units, perhaps paired with low-hydration (n <= 1) amorphous Mg-sulfates, indicated by the similar to 3,200 cm(-1) peak. Low-hydration MgSO4nH(2)O (n = 1-2) are more prevalent in the fan, and hydrated targets in the fan front only had one peak at similar to 3,400 cm(-1). While anhydrite co-occurs with hydrated Mg-sulfates in the crater floor and fan front, hydrated Ca-sulfates are observed instead at the top of the upper fan. Collectively, the data imply aqueous deposition of sediments with formation of salts from high ionic strength fluids and subsequent aridity to preserve the observed hydration states.

Volcanic eruptions carry essential information on the dynamics of volcanic systems. Studies have documented variable eruption styles and eruptive surface deformation. However, co-eruptive subsurface structural changes remain poorly understood. Here we characterize the seismic velocity changes from July 2019 to July 2023 at Great Sitkin Volcano in the central Aleutian volcanic arc, using single-station ambient noise interferometry at five three-component seismic stations. Coincident with the lava effusion since late July 2021, about two months after the explosive eruption on 26 May 2021, we observe a sustained velocity increase, most prominently to the northwest of the caldera. We attribute this velocity increase to the structural changes with magma extrusion, with the spatial variation controlled by the geometry of the magma system or the property of shallow volcaniclastics. Our findings offer insights into understanding co-eruptive structural modifications at active volcanoes.

We use the Ultraviolet Imaging of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey fields (UVCANDELS) to measure half-light radii in the rest-frame far-UV for similar to 16,000 disk-like galaxies over 0.5 <= z <= 3. We compare these results to rest-frame optical sizes that we measure in a self-consistent way and find that the stellar mass-size relation of disk galaxies is steeper in the rest-frame UV than in the optical across our entire redshift range. We show that this is mainly driven by massive galaxies (greater than or similar to 10(10) M-circle dot), which we find to also be among the most dusty. Our results are consistent with the literature and have commonly been interpreted as evidence of inside-out growth wherein galaxies form their central structures first. However, they could also suggest that the centers of massive galaxies are more heavily attenuated than their outskirts. We distinguish between these scenarios by modeling and selecting galaxies at z = 2 from the VELA simulation suite in a way that is consistent with UVCANDELS. We show that the effects of dust alone can account for the size differences we measure at z = 2. This indicates that, at different wavelengths, size differences and the different slopes of the stellar mass-size relation do not constitute evidence for inside-out growth.

The surface chemistry of pyrrhotites from intact particles directly collected from asteroid (162173) Ryugu was investigated by micro-Raman spectroscopy. The Raman peak characteristic to pyrrhotite was observed at around 115 cm-1 in Ryugu pyrrhotites, similar to freshly cleaved surfaces of terrestrial pyrrhotites. Additional Raman bands centered at around 220, 275, and 313 cm-1 with broadened features were also detected from the Ryugu pyrrhotites. The set of Raman bands at 220 and 275 cm-1 was assigned to typical Fe-S stretching vibrations of nu 2 (225 cm-1 ) and nu 1 (275 cm-1 ). These bands are not clearly observed in bulk crystals of pyrrhotite but appear in its nanoparticulate phase. These bands are ordinarily seen in amorphous monosulfides that formed under low oxygen fugacity ( f O 2 ) conditions in nature, indicating that the structural alteration of pyrrhotite surfaces occurred heterogeneously on the nanoscale under low f O 2 conditions. Further, the Raman band at 313 cm-1 was attributed to a characteristic tetrahedral bonding of Fe(III) in the lattice of Fe II 1-3x Fe III 1-2x S, followed by the local breakdown of the crystal lattice structures from planar bonding with Fe(II). In addition, some areas of the Ryugu pyrrhotite grains showed corroded structures with iridescence. Furthermore, assemblages of magnetite particles were also preferentially observed on small areas of the likely-dissolved pyrrhotite crystals in phyllosilicate matrices. These characteristic features in the Raman spectra and in corroded structures of Ryugu pyrrhotites record changes in the local environmental conditions via aqueous alteration. The corrosion of pyrrhotite crystals followed by the preferential formation of magnetite particles by asteroidal water is the likely product of dissolution of Fe(II) from the pyrrhotite surface and its oxidative precipitation in microchemical environments on the Ryugu parent body.

Background Genome assembly tools are used to reconstruct genomic sequences from raw sequencing data, which are then used for identifying the organisms present in a metagenomic sample.Methodology More recently, machine learning approaches have been applied to a variety of bioinformatics problems, and in this paper, we explore their use for organism identification. We start by evaluating several commonly used metagenomic assembly tools, including PhyloFlash, MEGAHIT, MetaSPAdes, Kraken2, Mothur, UniCycler, and PathRacer, and compare them against state-of-the-art deep learning-based machine learning classification approaches represented by DNABERT and DeLUCS, in the context of two synthetic mock community datasets.Result Our analysis focuses on determining whether ensembling metagenome assembly tools with machine learning tools have the potential to improve identification performance relative to using the tools individually.Conclusion We find that this is indeed the case, and analyze the level of effectiveness of potential tool ensembling for organisms with different characteristics (based on factors such as repetitiveness, genome size, and GC content).

Updates and corrections are made to a number of numerical entries and their references in Table 1 of the published article. Updated plots of the final run of the comparison of the tip of the red giant branch (TRGB) and Cepheid distances with metallicity, as seen in the lower panels of Figures 1 and 2 in the published article, are shown in the composite figure given here (Figure 1). The main conclusion of the published article, that there is no statistically significant correlation of the zero-point of the Cepheid period-luminosity relation with metallicity, is unchanged. The updated "statistically flat" regression is now found to be Delta mu (o)(Cepheid - TRGB) = -0.028 (+/- 0.019) x ([O/H] - 8.50) - 0.014 (+/- 0.042).

Net-zero chemical production can be achieved through electrification, biomass-based processes, and carbon capture, utilization, and storage. However, these net-zero pathways require more resources than business-as-usual processes. One possibility to produce net-zero chemicals at a lower resource consumption is the combination of net-zero pathways based on locally available resources. This study determines the optimal combinations of net-zero pathways for producing chemicals with net-zero emissions that minimize the use of renewable energy, land, and water while complying with local waste biomass and CO2 storage availability. Waste biomass is defined as residue biomass that does not compete for land and water with other sectors. The analysis is performed worldwide at the country level and considers the production of ammonia, methanol, and plastics, which, when combined, account for similar to 5% of the global CO2 emissions. Findings show that, when considering net-zero pathways individually, waste biomass is preferably used for producing ammonia and methanol, whereas carbon capture and storage is preferably deployed for plastics production. At the same time, a mixed strategy using carbon capture, utilization, and storage, and waste biomass, allows one to achieve a net-zero chemical industry with a nearly 60% reduction in energy consumption and 90% reduction in land and water consumption, with respect to single-pathway strategies. Finally, we find that adopting a net-zero portfolio that minimizes water allows water consumption to be reduced by more than 90% and land consumption to be reduced by more than 70% at the cost of an energy increase of only 5%, when compared to the minimum-energy portfolio.

A stylized macro-scale energy model of least-cost electricity systems relying only on wind and solar generation was used to assess the value of different storage technologies, individually and combined, for the contiguous U.S. as well as for four geographically diverse U.S. load-balancing regions. For the contiguous U.S. system, at current costs, when only one storage technology was deployed, hydrogen energy storage produced the lowest system costs, due to its energy-capacity costs being the lowest of all storage technologies modeled. Additional hypothetical storage technologies were more cost-competitive than hydrogen (long-duration storage) only at very low energy-capacity costs, but they were more cost-competitive than Li-ion batteries (short-duration storage) at relatively high energy- and power-capacity costs. In all load-balancing regions investigated, the least-cost systems that included long-duration storage had sufficient energy and power capacity to also meet short-duration energy and power storage needs, so that the addition of short-duration storage as a second storage technology did not markedly reduce total system costs. Thus, in electricity systems that rely on wind and solar generation, contingent on social and geographic constraints, long-duration storage may cost-effectively provide the services that would otherwise be provided by shorter-duration storage technologies.