• Contrasting geodynamic mechanisms simultaneously drive craton growth. • Case study into the evolution of the western Yilgarn Craton. • Early history of the South West Terrane is not shared across terrane boundarys. • Documentation of a Paleoarchean history in the South West Terrane. An outstanding question in Archean geodynamics is how the earliest continental crust was formed and stabilised, and how similar this process was to what is observed in the present day. Continental crust formation is often proxied by evidence of either allochthonous processes, such as terrane accretion and other subduction-like processes, or autochthonous processes involving in situ crustal growth and reworking. Subsequent interpretations are typically expressed in the terrane nomenclature for a given craton. An example is the Yilgarn Craton of Western Australia, which is associated with a wide range of tectonic models that incorporate various combinations of autochthonous and allochthonous processes. Despite these models, the South West Terrane and its connection to the rest of the Yilgarn Craton remain poorly understood. Here, this study addresses this paucity of data by reassessing the stratigraphic and magmatic history of the Toodyay area in the northern South West Terrane using integrated field mapping, U–Pb zircon geochronology, and Sm–Nd isotopic data. Our new data reveal evidence for a multistage Paleoarchean history of the South West Terrane, which modifies models of craton assembly. The > 3234 Ma Toodyay Formation is defined, which records a younger, more juvenile provenance distinct from age-equivalent quartzites in the Youanmi and Narryer Terranes of the Yilgarn Craton. Deposition was followed by 3234 ± 2 Ma magmatism and subsequent large-scale erosion, preserved as a unique unconformity spanning ages that are well represented in the rest of the craton. After this apparent hiatus, younger granitic suites (<2700 Ma) were emplaced in the South West Terrane that share geochemical signatures with coeval granites in the Youanmi Terrane. We interpret these data to indicate that an initially isolated South West Terrane was later juxtaposed with the Youami Terrane through lateral accretion, coinciding with extensive autochthonous growth in the Eastern Yilgarn (<2720). This suggests that allochthonous and autochthonous processes operated concurrently during craton formation and evolution, underscoring the complexity of Archean geodynamics beyond simple autochthonous or allochthonous models.

We present the search and characterisation of ionised outflows in a sample of 15 star-forming systems at z $ and outflow velocities V_ with no evidence of active galactic nuclei (AGNs) observed with the JWST/NIRSpec instrument in Integral Field Spectroscopic mode (IFS) as part of the `Galaxy Assembly with NIRSpec IFS' (GA-NIFS) program. Some of the target systems are comprised of various individual galaxies, adding up to a total of 40 individual objects. Our sample encompasses the high mass end of the galaxy populations, with most of the sample having stellar masses within log_10 (M_⋆/M_⊙) = 9.5-11, while previous studies on high-z star formation driven outflows generally contain galaxies of log_10 (M_⋆/M_⊙)$&lt;9.5$. Leveraging the spatially resolved information and rest-frame optical coverage provided by NIRSpec IFS data, we analysed the and ̋a emission lines to search for broad kinematic components associated with galactic outflows. Crucially, the IFS observations allowed us to directly isolate the regions hosting the outflows, rather than relying on integrated spectra. We identified signatures of ionised outflows in 16 individual galaxies/regions (in 13 out of 15 systems), although we consider two of them only as `candidates', as they could be related to mergers or tidal interactions. After constraining their spatial location and extent, we characterised the integrated properties of the outflowing gas and evaluated the impact on the host galaxies. We find that the outflowing gas is more dust attenuated (by A_ ̊m V mag on average) and metal enriched (sim0.13 dex) than the interstellar medium of the host galaxies, suggesting that outflows contribute to distributing dust and metals around them. The outflows identified in this study present velocity dispersions within σ_ ̊m out km s -1 ̊m out km s^-1. Considering also less luminous and less massive star-forming galaxies from previous works, there is a statistically significant correlation between outflow velocity (v_̊m out) and star formation rate (SFR). The generally low mass-loading factors (η= _ ̊m M ̊m out /SFR $&lt;1, in nine out of 14 outflows) obtained for the ionised outflows suggest that they do not suppress star formation in the host galaxies. Moreover, their velocities are not high enough to escape their hosts and reach the circumgalactic medium. Our results indicate that ejective feedback through ionised outflows is inefficient in high-mass and luminous star-forming galaxies within the first 2 Gyr of cosmic time.

The so-called ``Galactic center lobe'' (GCL) is an extended (∼1̧irc) radio continuum feature situated above the Galactic plane, the nature and location of which have been subject to varying claims in the literature. Using new optical integral field spectroscopic observations from the SDSS-V Local Volume Mapper, we confirm the characterization of the GCL as a foreground photoionized region, not associated with the Galactic center. We present a new analysis of the ionized gas morphology, line ratio diagnostics, and kinematics. From our emission line map, which suffers the least extinction, we identify ionized gas emission throughout a closed outer loop, which does not fill the GCL interior. All optical line ratio diagnostics are consistent with photoionization. By comparing the ionized gas reddening from the Balmer decrement with 3D dust maps, we directly constrain the distance to the GCL to ∼2 kpc. ∋iłambda6583 line kinematics show a uniform velocity structure across the GCL, further confirming that the entire bubble is one structure. The size and emission line morphology is strongly reminiscent of that seen in the nearby Barnard's Loop, providing a possible analog to explain how this outer shell may be photoionized by a more distant and off-center embedded young cluster. We suggest that the acronym GCL be repurposed to instead abbreviate the name ``greatly confused loop'’.

Massive quenched galaxies at z&gt;3 challenge models of early galaxy evolution, as their rapid formation and abrupt quenching require efficient feedback, which is often linked to active galactic nuclei (AGNs). The quiescent galaxy at z=3.064 is a key example of this population. Previous JWST/NIRSpec integral field unit (IFU) observations revealed an AGN-driven outflow and uncovered a compact pair of AGNs separated by sim5 kpc. In addition, VLT/MUSE spectroscopy identified a third AGN candidate at a projected distance of sim30 kpc, associated with a luminous łya emitter (LAE2) characterised by high-ionisation UV lines, although rest-frame optical diagnostics were not previously available. We aim to confirm the nature of LAE2 using rest-frame optical diagnostics enabled by new JWST observations, and to characterise the physical and ionisation properties of both LAE2 and a distinct nearby łya emitter (LAE1) that lacks any detectable continuum counterpart. Through this analysis, we investigated the interplay among low-mass satellites, black-hole growth, and the ionised environment of a quenched massive galaxy at high redshift. We analysed new JWST/NIRSpec IFU observations targeting the optical nebular lines of LAE1 and LAE2, including and ∋i, complemented with VLT/MUSE IFU spectroscopy, as part of the GA-NIFS project. We extracted integrated and spatially resolved spectra, constructed emission-line maps, and used standard diagnostic diagrams to determine ionisation sources and kinematics. LAE2 exhibits rest-frame UV–optical-line ratios fully consistent with an embedded AGN. Its and emission displays a clumpy morphology and irregular, non-rotating kinematics on sub-kiloparsec scales. Except for łya, LAE1 remains undetected in all nebular lines and in JWST imaging; its łya emission is broad (σ ∼ 200 ̨ms) and asymmetric. The similarity of the LAE1 and LAE2 łya profiles in both velocity and flux suggests that LAE1 traces resonantly scattered emission powered by LAE2 rather than in situ star formation (although the latter cannot be completely ruled out). Our analysis reveals that the environment of contains both multi-black-hole activity and gas structures on tens-of-kiloparsec scales, offering new insights into how feedback, accretion, and satellite interactions influence the late evolutionary stages of quenched massive galaxies.

Freshwater gastropods are among the most imperiled organisms globally, and taxonomic uncertainty remains a major obstacle to their conservation. Elimia melanoides (Conrad, 1834), previously presumed extinct, was rediscovered in the Black Warrior River drainage of Alabama, prompting renewed interest in its conservation status. However, persistent taxonomic uncertainty has hindered listing under the U.S. Endangered Species Act. We used integrative taxonomy-including extensive field sampling, 3RAD-based phylogenomics, and morphological analysis of museum specimens-to resolve the taxonomy of E. melanoides sensu lato. Our molecular phylogenetic analyses revealed that E. melanoides, as currently conceived, comprises three distinct lineages: E. melanoides sensu stricto, Elimia hydeii (Conrad, 1834) (in part), and Elimia turgida (Haldeman, 1840), which we restore from synonymy. Comparison to historical museum specimens indicates that the extant lineage currently identified as E. melanoides is not conspecific with the taxon described as Anculosa melanoides by Conrad. We propose to follow prevailing usage and retain the name E. melanoides for the extinct taxon described by Conrad. There is no available name for the extant taxon, which we describe here as Elimia mintoni n. sp. Population genomic analyses revealed high genetic structure in E. mintoni n. sp. and E. hydeii, especially in headwater populations, while E. turgida showed no structure across its narrow range but maintains high genetic diversity. These findings have urgent conservation implications: E. mintoni n. sp. and E. turgida are valid, range-restricted species with low redundancy and representation. Our study underscores the necessity of taxonomic resolution for accurate biodiversity assessments and effective conservation planning.

Rhizosphere reprogramming by integrated bio‑organic fertilizer and seed coating mitigates atrazine phytotoxicity in soybeans.

Galaxy mergers are known to trigger bursts of central star formation, which should therefore lead to stellar mass growth in their inner regions. However, observational measurements of this `burst mass fraction’ are scant. Here, we assemble a large (~ 14,000) sample of post-coalescence galaxies that have recently completed their merger-induced star formation, and compare various measurements of central stellar mass with a matched control sample. Specifically, we quantify (at fixed redshift, star formation rate and total stellar mass) the stellar mass enhancement within a fixed angular aperture (Delta M ,fibre) and in the galactic bulge (Delta M_ ,bulge), finding burst mass fractions of 10 – 20 %. 61 galaxies in our sample are at z&lt;0.05 and have integral field unit data from the Mapping Galaxies at Apache Point (MaNGA) survey, allowing further kpc-scale assessment of excess stellar mass and radial gradients. When assessed within apertures defined in units of kpc we again find a ~ 15 – 20 % excess of stellar mass in the central regions of the post-mergers compared with matched controls. However, within apertures defined in units of effective radius this stellar mass enhancement increases to 40 %, suggesting that the relative structure/size of the galaxy is important for regulating the location of the merger induced star formation. Moreover, we find that these stellar mass enhancements are spatially extended, out to ~ 7 kpc or around 1 R/Re, although the small sample size of the MUMMI-MaNGA overlap limits our radial sampling. Our work represents the first direct measurement of merger-induced stellar mass that is independent of stellar population modelling, or fitting light profiles, demonstrating significant and extended mass build-up in late stage post-mergers.

Full-spectrum fitting is the prevailing method for extracting stellar kinematic and population measurements from 1D galaxy spectra. 3D methods refer to an analysis of integral field spectroscopy (IFS) data, where the spatial and spectral dimensions are modelled simultaneously. While several 3D methods exist for modelling gas structures probed by a single emission, the more computationally demanding problem of 3D full-spectrum fitting for stellar recoveries has been investigated less frequently. We introduce and compare two algorithms for 3D full-spectrum fitting: the projected Nesterov Kaczmarz reconstruction method (PNKR), and a version of the Bayes-LOSVD software, which we modified to account for spatial correlations. The former is an iterative regularisation method that models the joint density over stellar populations and kinematics. The latter is a probabilistic method for kinematic recoveries. We aim to understand the strengths and weaknesses of the two algorithms and assess the effect of 3D methods for stellar inferences. We applied the two recovery algorithms to mock IFS data with a ground-truth model resembling a counter-rotating galaxy, over a signal-to-noise ratio (S/N) range from 20-200. We evaluated the quality of the recoveries compared to the known ground truth. Accounting for spatial correlations in Bayes-LOSVD significantly improved the accuracy and precision of kinematic recoveries. 3D modelling with PNKR did not provide any significant improvement over 1D fits, but for S/N&gt;40, PNKR recovered the most accurate kinematics overall. Additionally, by modelling the joint distribution over kinematics and populations, PNKR successfully inferred trends between these quantities. For instance, it inferred local metallicity-velocity trends, but with a significant bias on the absolute metallicity. This successful demonstration of joint kinematic-population analyses includes cases when the counter-rotating components are not spectroscopically well-resolved. After demonstrating the advantages of (i) 3D modelling with Bayes-LOSVD and (ii) joint kinematic-population analyses with PNKR, we conclude that the two methodological advances will prove useful for detecting and characterising stellar structures from IFS data.

High-redshift radio galaxies can provide important insights into structure formation and galaxy evolution during earlier cosmological epochs. TGSS,J1530$+1049 was selected as a candidate high-redshift radio galaxy based on its very steep radio spectrum. Subsequent observations with the James Webb Space Telescope ( JWST ) presented in a companion paper have shown that it is located at a redshift of z=4.0$. The JWST data furthermore showed that the radio source is part of one of the densest structures of galaxies and ionized gas known at these redshifts. The complex system qualitatively resembles a massive (cluster) galaxy that formed early through a rapid succession of mergers. TGSS,J1530$+1049 is an unresolved source down to an ∼ 0.6 scale in multiple radio surveys. To reveal its high-resolution radio structure and allow for a detailed comparison with JWST observations, we studied its morphology at various angular scales with different radio interferometric instruments. We observed TGSS,J1530$+1049 at a milliarcsecond- (mas) scale angular resolution with the European VLBI Network (EVN), and at an ∼ 100$-mas scale resolution with the enhanced Multi-Element Remotely Linked Interferometer Network (e-MERLIN). We recovered a complex north--south oriented structure with steep-spectrum radio-emitting features, which are associated with the lobes and hot spots of a jetted active galactic nucleus. However, the centre of the radio galaxy proved to be too faint at centimetre wavelengths to be unambiguously detected in our observations. Nevertheless, its linear size (sim5.5 kpc) and radio power (L_ W Hz 1.4GHz 27 -1 $) place it among the so-called medium-sized symmetric objects, which are a smaller and/or confined version of larger radio galaxies. A comparison between its radio morphology and that of the ionized gas as observed with the NIRSpec integral field unit on JWST shows that the two are closely aligned. However, the optical emission line gas extends out to $ kpc, which is well beyond the detected radio structures.

An integrative field and modelling study of the bottom-up, top-down and indirect effects of native species on invasive insects and their biological control: the case of the worldwide chestnut tree pest, Dryocosmus kuriphilus, in the French Eastern Pyrenees

Abstract We utilize James Webb Space Telescope/Mid Infrared Instrument (JWST/MIRI) Integral Field Unit observations from the Galaxy Activity, Torus and Outflow Survey to investigate the diverse range of ionized outflow rates of obscured active galactic nuclei (AGN) with similar bolometric luminosity and explore potential associations with AGN feedback. We explore spatial correlations between ionized emission potentially associated with fast shocks ([Fe II ] 5.34 μ m ) and the excitation of H 2 . We further constrain our investigation to the inner 400 pc (the nuclear and circumnuclear regions r &lt; 200 pc), and estimate the excitation temperature and column density of H 2 assuming local thermodynamic equilibrium and using the S(1)–S(8) rotational H 2 emission lines visible to JWST/MIRI spectroscopy. We report the molecular gas temperature of the deprojected 400 pc nuclear region to correlate with the ionized mass outflow rate. We also observe a stronger degree of spatial correlation between [Fe II ] 5.34 μ m emission and H 2 gas temperature. We observe regions of enhanced [Fe II ] 5.34 μ m /[Ar II ] 6.99 μ m spatially coincident with the ionization cones of objects with higher ionized outflow rates and [Fe II ] 5.34 μ m /[Ar II ] 6.99 μ m in the deprojected 400 pc nuclear region to scale positively with both the ionized outflow rate and the estimated molecular gas temperature. We do not observe the estimated jet cavity power within the central 400 pc as strongly correlated with the ionized mass outflow rate or molecular gas temperature of the nuclear region. We take the preceding observations to suggest a higher degree of interaction between AGN outflows and the circumnuclear disk.

Abstract The abundance discrepancy problem refers to the systematic differences observed between chemical abundances derived from collisionally excited lines (CELs) and recombination lines (RLs) of heavy ions. It remains a major unsolved problem in the study of ionized nebulae and is quantified by the abundance discrepancy factor (ADF). In this work, we present a deep integral field spectroscopic data set of the entire Lagoon Nebula (M8), obtained by the Sloan Digital Sky Survey V Local Volume Mapper project, at a spatial resolution of 0.21 pc spaxel −1 . This unique data set allows us, for the first time, to investigate spatially resolved maps of oxygen RL intensities (O ii V1), together with maps of H i RLs, heavy-ion CELs, and dust attenuation across a whole H ii region. We map the electron temperature using CELs and RLs of O 2+ and CELs of N + , and we map the electron density using CELs of S + . We derive CEL-based ionic and elemental oxygen abundances and, for the first time, a spatially resolved map of the RL-based O 2+ abundance in an H ii region. These measurements enable construction of the first spatially resolved ADF(O 2+ ) map of an H ii region and yield a global mean ADF of ∼0.47 ± 0.02 dex. Focusing on the central region of M8, where ionization is dominated by the O-type star Her 36, we find radial variations in the ADF, ranging between ∼0.35 and 0.50 dex. Our findings provide novel constraints on the spatial behavior and origin of the abundance discrepancy in the H ii regions.

The narrow-line Seyfert 1 galaxy IRAS 17020+4544 is one of the few known sources to exhibit a multiphase outflow in the highly ionized and molecular phases consistent with active galactic nucleus (AGN) feedback operating in the ``energy-conserving'' regime. We aim to characterize the properties of the ionized warm ionized gas in IRAS 17020+4544 using new optical integral-field spectroscopic (IFS) data, and to assess the presence of outflowing ionized gas and its connection with the other gas phases and its role in the AGN feedback. We analyzed new optical seeing-limited IFS observations obtained with MEGARA at the Gran Telescopio Canarias in both low- (R∼6000; LR) and medium-resolution (R∼12000; MR) modes. We modeled the Hα and OIII łambda5007 emission lines using multi-Gaussian fitting to characterize in detail the ionized gas kinematics, particularly that of the ionized outflow, in order to derive its energetics and compare it with those of the X-ray and molecular phases. Diagnostic diagrams (WHAN, WHaD, and BPT) were used to investigate the dominant ionization mechanism. We identify a fast ionized outflow traced by both Hα and OIII emission lines, with similar extensions (R_ line. The fast outflow follows an energy-conserving regime in both Hα and the kpc and ∼0.5 kpc, respectively) and velocities (v_ $, respectively). A slower ionized outflow (v_ ) is also detected in the secondary component of the ∼ 1460 and 1240 km s -1 km s$^ -1 OIII OIII lines (from the LR setup), while the slower outflow follows a ``momentum-driven'' regime. The ionized outflows are enclosed within the molecular outflow detected with NOEMA (R_ kpc), and the large momentum boosts derived in both phases suggest efficient AGN feedback, likely dominated by radiatively driven winds (quasar-mode) rather than kinetic (jet-driven) processes. Ionization diagnostics indicate that the outflow is primarily AGN-driven, although a contribution from star-formation-driven excitation cannot be ruled out, and some contribution from shocks cannot be excluded on smaller scales. Our results support a scenario in which the multiphase outflow in IRAS17020+4544 is AGN-driven and energy-conserving in the different (i.e., highly ionized, warm ionized, and molecular) phases, efficiently coupling the AGN energy to the host galaxy's interstellar medium. The molecular outflow appears to be the dominant phase, while the ionized phase contributes less to the mass budget and feedback efficiency.

Active Galactic Nuclei (AGN) are intertwined with galaxy evolution, injecting energy into the interstellar medium (ISM) and possibly regulating star formation as a galaxy evolves. However, the phenomena through which we observe AGN are multiphase and multiscale, which can lead to conflicting results for how significantly and to what extent AGN influence the ISM. M51 is a perfect case study of the boundary between where AGN feedback and star formation feedback dominate the ISM, hosting a low-luminosity type II Seyfert nucleus with a well-defined molecular and ionized outflow. We endeavor to characterize the spatial extent and dominant modes of AGN feedback in M51 utilizing multiple phases of the ISM. Using integral field spectroscopy observations from VENGA of the central 3 kpc, we identified regions dominated by AGN ionization using an emission line ratio (ELR) function. We then combined this information with new observations of the dense molecular ISM in M51 from SWAN, including cloud-scale mapping of HCN(1--0), HNC(1--0), HCO+$(1--0), and N_2H^+(1--0). Both datasets allowed us to achieve $∼180,pc resolution, allowing for a clear demarcation of where AGN feedback dominates the ISM. We then tested how the ELR compares to other tracers of AGN activity, using both millimeter emission line ratios as well as X-ray observations from Chandra to assess the dominant mode of feedback. If we assume that N_2H+$(1--0) is the best tracer of dense, cold gas in SWAN, then AGN-dominated regions defined by the ELR all have greater emission in (1--0) transitions in HCN, HNC, and HCO^+ than would be expected if they traced dense gas alone, implying excitation of these lines from AGN feedback. The ELR is better at selecting these regions compared to molecular tracers of AGN activity, such as HCN(1--0)/HCO^+(1--0), which are heightened for a greater extent in M51. Some of the highest ELR values are also associated with fast shocks evident in the optical, which are concurrent with large HNCO(4--3)/CO(1--0) values that point to slow shocks near the nucleus. The presence of shocks and heightened N_2H$^+(1--0) near the nucleus indicate a potential dense molecular outflow, meaning heightened dense tracer emission could be partly due to larger abundance rather than excitation alone in this limited region. All tracers of AGN activity point to a ``two-stage'' feedback scenario, whereby mechanical feedback from the jet-ISM interaction spurs soft X-ray emission that excites molecules such as HCN. Dense gas entrenched in a molecular outflow may also lead to a greater chemical abundance of multiple tracers measured with SWAN, but to a lesser extent than excitation from AGN feedback.

In this study, a higher-order approach incorporating a new polynomial-exponential integral shear strain field is established to examine the vibration response of functionally graded (FG) nanobeams subjected to hygrothermal loading and material composition imperfections. The formulation employs a displacement field with undetermined integral terms and considers four hygrothermal environments: uniform, linear, nonlinear, and sinusoidal distributions. The nanobeam rests on a Winkler–Pasternak elastic foundation, and three porosity patterns based on cosine-type functions are examined. A power-law scheme describes the disparity of constituent materials across the thickness, including temperature-dependent mechanical properties. The analysis explores the influence of environmental conditions, material gradation, porosity profiles, nonlocal impacts, and foundation stiffness on natural frequencies. The outcomes deliver a comprehensive context for future research on the dynamic behavior of advanced graded nanostructures.

Abstract As an advanced optical imaging method, polarization imaging technology introduces polarization dimension information on the basis of traditional imaging. It can simultaneously acquire the polarization characteristics of targets and backgrounds, thereby significantly improving the imaging recognition and analysis capabilities. In this paper, a mid-infrared full-Stokes polarization focal plane zoom metasurface operating in the 4.5-5 μm waveband is designed. Based on an all-silicon dielectric design, this structure has real-time zoom capability and exhibits lower dispersion and smaller polarization crosstalk compared with the modulation mechanisms of existing zoom metalenses. Simulation results show that the full width at half maximum (FWHM) of the focal spot formed by the metasurface is close to the diffraction limit under different polarization states and wavelengths. With its simple structure and weak crosstalk, this design has broad application prospects in the fields of mid-infrared polarization imaging and optical system integration.

Major advances in understanding human biology and health have been made possible by long-term field research projects with Indigenous peoples, whose ecological settings and lifeways are distinct from majority populations in high-income settings. Long-term fieldwork is central to human biology, yet much about this research approach remains opaque. This paper considers a single long-term study-the Shuar Health and Life History Project in Amazonian Ecuador-and discusses how we have navigated practical, political, and ethical challenges of initiating and maintaining a two-decade long collaborative project with integrative field and laboratory components. By enhancing transparency and offering logistical and ethical insights, our goal is to provide guidance to researchers. We offer three sets of conclusions and recommendations. First, our highly integrative approach allows us to ask important scientific questions and answer them in innovative ways. We recommend investment in broad theoretical and methodological training and study design, as well as a project structure that nurtures students' ideas. Second, a project like ours is extremely challenging to operate, requiring major sustained commitment of time and funding to maintain the fieldsite and laboratories. We recommend that scientists initiating major field projects be cognizant of these enormous costs and challenges, develop supportive relationships among collaborating researchers, and incorporate flexibility and excess capacity. Finally, sustainable long-term investment in research communities must be prioritized, and the science and outreach efforts require tailoring to local conditions and realities. We recommend that researchers invest deeply in communities, building trust and establishing long-term relationships that are mutually beneficial.

This paper aims to map the room for manoeuvre in European tax integration and thereby confront the discourse on (tax) sovereignty in general terms, as well as specifically for the European Union (EU). In doing so, it examines the historical development of European tax integration, focusing on the constitutional interplay between the EU and its Member States that should inform the legal debate on the correct allocation of taxing powers between the Union and its Member States. The starting point is that the Treaties themselves establish the creation of an internal market as an explicit goal, including taxation. Direct taxation is the field where this goal has not materialized, and this paper draws the direction of travel from the legal discussion on sovereignty, specifically applied to the context of taxation. It offers a new approach to the broader debate on European integration in taxation and limits sovereignty-based reasoning to legal argumentation, thereby depoliticizing the discourse.

A Slit Mask Integral Field Unit for the Robert Stobie Spectrograph on the Southern African Large Telescope. I. Instrument Development

Abstract The interstellar comet 2I/Borisov is the first interstellar object where compositional characterisation was possible throughout its entire perihelion passage. We report all 16 epochs of a comprehensive optical observation campaign with ESO Very Large Telescope’s integral field spectrograph MUSE, spanning 126 days from 2019 November 14 to 2020 March 19. The spatial dust emission of 2I/Borisov was predominantly smooth, with no seasonal effect. A jetlike feature was consistently visible. The gas production morphology of its coma was also smooth and similar for C 2 , NH 2 , and CN: symmetric around the optocentre. The production rates of these species gently declined into and beyond perihelion, until 2I’s outburst and splitting event in early 2020 March. C 2 , NH 2 , and CN production rates all increased, with NH 2 being the most significant; the dust emission also slightly reddened. 2I/Borisov is a carbon-depleted, relatively NH 2 -rich comet when compared to those comets yet measured in the solar system.