Search Results (63)

Background/Objectives: Sotatercept has demonstrated efficacy in pulmonary arterial hypertension (PAH), but its use has not been studied in patients with Group 3 pulmonary hypertension (PH). Additionally, patients with connective tissue disease-associated PAH (CTD-PAH) were underrepresented in the STELLAR trial. Given the limited treatment options for pulmonary hypertension in patients with interstitial lung disease (PH-ILD), this study aimed to evaluate the use of sotatercept in CTD-PAH patients with concomitant ILD. Methods: Eligible patients (n = 7) had a confirmed diagnosis of CTD-PAH with concomitant ILD. The patients were already receiving background PAH therapy. Baseline hemodynamic and clinical measurements were reassessed after 24 weeks of sotatercept therapy. The variables assessed included six-minute walk distance (6MWD), pulmonary vascular resistance (PVR), echocardiographic right ventricular systolic pressure (eRVSP), N-terminal pro-brain natriuretic peptide (NT-proBNP) levels, World Health Organization (WHO) functional class, and supplemental oxygen requirements. Results: The study included seven patients with a mean age of 57 years (range: 39–73 years). After 24 weeks, the mean 6MWT distance increased from 211 m to 348 m (p < 0.01). Mean PVR decreased from 7.77 WU at baseline to 4.53 WU (p < 0.01). Mean eRVSP decreased from 79.43 mmHg to 54.14 mmHg (p < 0.01). NT-proBNP decreased from 3056.86 pg/mL to 1404.29 pg/mL (p < 0.01). The WHO functional class and supplemental oxygen requirements improved in all patients. Conclusions: Sotatercept was tolerated in patients with CTD-PAH and ILD, with no evidence of adverse respiratory effects. When added to foundational PAH therapy, sotatercept resulted in significant improvements across multiple parameters. These findings suggest that sotatercept may be a promising therapeutic option as an adjunctive treatment in this patient population. Full article

Observations provided by the Hubble Space Telescope (HST) and James Webb Space Telescope (JWST) have revealed a surprising abundance of galaxies at the “cosmic dawn” epoch, $z>7$. Some of them are found even in a more distant universe at z ≃ 14–16. Most of these galaxies appear to be intriguing: they are found to be either super-bright in the rest-frame ultraviolet (UV) band or super-dusty with a heavily reddened stellar population. The transition from the super-bright and super-dusty regimes seems to occur in the redshift range from z∼10.5 to z∼9.5 within a time range of ∼50 Myr. If confirmed, then the origin of this transition is far from being clear. In the review, we discuss possible mechanisms that can make $z>10$ galaxies free of dust and also explain the origin of apparently excessive dust in galaxies at intermediate and lower redshifts $z<10$. Full article

Cryptocurrencies have gained global recognition, yet their rapid expansion is accompanied by significant environmental concerns due to their energy-intensive operations. This study employs novel system thinking and system dynamics approaches to examine the impact of cryptocurrencies on energy use, water consumption, and carbon emissions. The findings underscore the significant negative environmental impact resulting from cryptocurrency mining. According to our results, in 2023, the water consumption and carbon emissions of cryptocurrencies amounted to 1859 × 10⁶ m³ and 90.6 × 10⁶ tons CO₂e (0.25% of global CO₂ emissions), respectively, linked to the consumption of 119.7 × 10⁶ MWh of electricity (0.5% of global electricity consumption). To provide context, this volume of water could fulfill the basic drinking water and sanitation needs of a global population that lacks access. Similarly, the electricity consumption equates to supplying a country like Argentina, which has a population of nearly 46 million. Without intervention, these figures are projected to increase sixfold by 2030. We recommend the adoption of renewable energy curtailment for Proof-of-Work cryptocurrency mining. Alternatively, technologies like the Pi network, based on the Stellar Consensus Protocol, offer a sustainable and energy-efficient solution. Full article

Spectropolarimetric techniques are a mainstay of astrophysical inquiry, ranging from Solar System objects to the Cosmic Background Radiation. This review highlights applications of stellar polarimetry for massive hot stars, particularly in the context of ultraviolet (UV) spaceborne missions. The prevalence of binarity in the massive star population and uncertainties regarding the degree of rotational criticality among hot stars raises important questions about stellar interactions, interior structure, and even the lifetimes of evolutionary phases. These uncertainties have consequences for stellar population synthesis calculations. Spectropolarimetry is a key tool for extracting information about stellar and binary geometries. We review methodologies involving electron scattering in circumstellar envelopes; gravity darkening from rapid rotation; spectral line effects, including the (a) “line effect”, (b) Öhman effect, and (c) Hanle effect; and the imprint of interstellar polarization on measurements. Finally, we describe the Polstar UV spectropolarimetric SMEX mission concept as one means for employing these diagnostics to clarify the state of high rotation and its impacts for massive stars. Full article

Accreting white dwarf binaries (AWDs) comprise cataclysmic variables (CVs), symbiotics, AM CVns, and other related systems that host a primary white dwarf (WD) accreting from a main sequence or evolved companion star. AWDs are a product of close binary evolution; thus, they are important for understanding the evolution and population of X-ray binaries in the Milky Way and other galaxies. AWDs are essential for studying astrophysical plasmas under different conditions along with accretion physics and processes, transient events, matter ejection and outflows, compact binary evolution, mergers, angular momentum loss mechanisms, and nuclear processes leading to explosions. AWDs are also closely related to other objects in the late stages of stellar evolution, with other accreting objects in compact binaries, and even share common phenomena with young stellar objects, active galactic nuclei, quasars, and supernova remnants. As X-ray astronomy came to a climax with the start of the Chandra and XMM-Newton missions owing to their unprecedented instrumentation, new excellent imaging capabilities, good time resolution, and X-ray grating technologies allowed immense advancement in many aspects of astronomy and astrophysics. In this review, we lay out a panorama of developments on the study of AWDs that have been accomplished and have been made possible by these two observatories; we summarize the key observational achievements and the challenges ahead. Full article

Star-forming galaxies are hosts of dominant populations of recently formed, hot, massive stars, which give rise to conspicuous stellar spectral features and provide the ionizing fluxes. Strong outflows of these stars shape their properties. These winds affect the evolution and the output of ionizing radiation, as well as the energy and momentum input in the interstellar medium and the chemical enrichment. Many properties of massive stars become even more extreme at a low metallicity. Owing to the pioneering observations of young, metal-poor stellar populations, both locally with HST and large ground-based facilities and at high redshift with JWST, we are at a key moment to assess our understanding of hot massive stars in these galaxies. Stellar population synthesis is a key tool. I will demonstrate how population models of hot, massive stars help to address some issues at the forefront of current research. The recent advent of new evolutionary and atmosphere models of massive stars probing new parameter space allows us to characterize the properties of nearby and distant populations. Full article

This review provides an observational perspective on the fundamental properties of super-Eddington accretion onto supermassive black holes in quasars. It begins by outlining the selection criteria, particularly focusing on optical and UV broad-line intensity ratios, used to identify a population of unobscured super-Eddington candidates. Several defining features place these candidates at the extreme end of the Population A in main sequence of quasars: among them are the highest observed singly-ionized iron emission, extreme outflow velocities in UV resonance lines, and unusually high metal abundances. These key properties reflect the coexistence of a virialized sub-system within the broad-line region alongside powerful outflows, with the observed gas enrichment likely driven by nuclear or circumnuclear star formation. The most compelling evidence for the occurrence of super-Eddington accretion onto supermassive black holes comes from recent observations of massive black holes at early cosmic epochs. These black holes require rapid growth rates that are only achievable through radiatively inefficient super-Eddington accretion. Furthermore, extreme Eddington ratios, close to or slightly exceeding unity, are consistent with the saturation of radiative output per unit mass predicted by accretion disk theory for super-Eddington accretion rates. The extreme properties of super-Eddington candidates suggest that these quasars could make them stable and well-defined cosmological distance indicators, leveraging the correlation between broad-line width and luminosity expected in virialized systems. Finally, several analogies with accretion processes around stellar-mass black holes, particularly in the high/soft state, are explored to provide additional insight into the mechanisms driving super-Eddington accretion. Full article

Over the past two decades, our understanding of star formation has undergone a major shift, driven by a wealth of data from infrared, submillimeter and radio surveys. The emerging view depicts star formation as a hierarchical process, which predominantly occurs along filamentary structures in the interstellar medium. These structures span a wide range of spatial scales, ultimately leading to the birth of young stars, which distribute in small groups, clusters and OB associations. Given the inherently complex and dynamic nature of star formation, a comprehensive understanding of these processes can only be achieved by examining their end products—namely, the distribution and properties of young stellar populations. In the Gaia era, the nearby OB associations are now characterised with unprecedented detail, allowing for a robust understanding of their formation histories. Nevertheless, to fully grasp the mechanisms of star formation and its typical scale, it is essential to study the much larger associations, which constitute the backbones of spiral arms. The large catalogues of young open clusters that have emerged from Gaia DR3 offer a valuable resource for investigating star formation on larger spatial scales. While the cluster parameters listed in these catalogues are still subject to many uncertainties and systematic errors, ongoing improvements in data analysis and upcoming Gaia releases promise to enhance the accuracy and reliability of these measurements. This review aims to provide a comprehensive summary of recent advancements and a critical assessment of the datasets available. Full article

Planetary nebulae (PNe) are the ejected gas and dust shells of evolved low- and intermediate-mass stars (LIMSs). We present an abundance comparison between PNe and their progenitors to reveal their similarities and differences since such a comparison has rarely, and not recently, been performed in the Milky Way. The dynamical expulsion of the outer envelope of an evolved LIMS produces the PN. We expected similarities in most $\alpha$-element distributions across the stellar and nebular populations, given that these elements are only marginally produced and destroyed during the LIMS evolution. Differences found in the Fe and S abundances allow us to determine their depletion due to grain condensation in the post-AGB phases. Differences in N and C between PNe and their progenitors set new limits to the low- and intermediate-mass star contributions to these elements. Finally, radial metallicity gradients from evolved LIMS and PNe and Gaia-calibrated distances constrain Galactic evolution in the framework of the current chemical evolutionary models. We found the following: (1) Gas-phase iron is significantly depleted in PNe compared to their progenitor stars, with an average depletion factor of <D[Fe/H]> = 1.74 ± 0.49. (2) Sulfur is also depleted in PNe, though to a much lesser extent than iron. (3) The median enrichment levels for carbon and nitrogen relative to the median stellar population of the same metallicity are approximately [C/H] ∼ +0.3 and [N/H] ∼ +0.4, respectively. PNe with progenitors that experienced hot-bottom burning (HBB) exhibit extreme nitrogen enrichment. (4) With the data available to date, the radial metallicity gradient derived from evolved LIMSs and PNe are compatible within the uncertainties. Full article

The Large and Small Magellanic Clouds (LMC and SMC) form the closest interacting galactic system to the Milky Way, therewith providing a laboratory to test cosmological models in the local Universe. We quantify the likelihood for the Magellanic Clouds (MCs) to be observed within the $\mathsf{\Lambda }$CDM model using hydrodynamical simulations of the IllustrisTNG project. The orbits of the MCs are constrained by proper motion measurements taken by the Hubble Space Telescope and Gaia. The MCs have a mutual separation of $d_{\mathrm{MCs}}=24.5\mathrm{kpc}$ and a relative velocity of $v_{\mathrm{MCs}}=90.8\mathrm{km}{\mathrm{s}}^{-1}$, implying a specific phase-space density of $f_{\mathrm{MCs},\mathrm{obs}}\equiv {(d_{\mathrm{MCs}}·v_{\mathrm{MCs}})}^{-3}=9.10\times {10}^{-11}{\mathrm{km}}^{-3}{\mathrm{s}}^3{\mathrm{kpc}}^{-3}$. We select analogues to the MCs based on their stellar masses and distances in MW-like halos. None of the selected LMC analogues have a higher total mass and lower Galactocentric distance than the LMC, resulting in >3.75$\sigma$ tension. We also find that the $f_{\mathrm{MCs}}$ distribution in the highest resolution TNG50 simulation is in $3.95\sigma$ tension with observations. Thus, a hierarchical clustering of two massive satellites like the MCs in a narrow phase-space volume is unlikely in $\mathsf{\Lambda }$CDM, presumably because of short merger timescales due to dynamical friction between the overlapping dark matter halos. We show that group infall led by an LMC analogue cannot populate the Galactic disc of satellites (DoS), implying that the DoS and the MCs formed in physically unrelated ways in $\mathsf{\Lambda }$CDM. Since the ${20}^{\circ }$ alignment of the LMC and DoS orbital poles has a likelihood of $P=0.030$ ($2.17\sigma$), adding this ${\chi }^2$ to that of $f_{\mathrm{MCs}}$ gives a combined likelihood of $P=3.90\times {10}^{-5}$ ($4.11\sigma$). Full article

In this review, we highlight the contributions made by the Swift/UVOT instrument to the understanding of the ultraviolet (UV) attenuation and extinction properties of interstellar dust and provide insight into hot stars and young stellar populations. The study of these two fields is interconnected: UV-bright objects can only be understood if the effects of foreground dust are accounted for, but foreground dust can only be accounted for by studying the properties of UV-bright objects. Decades worth of work have established that the effects of dust on background starlight vary in the ultraviolet, with proposed extinction laws having a wide variety of slopes and a strong “bump” spectroscopic feature at 2175 Å. We show that UVOT is uniquely suited to probe variations in the UV extinction law, specifically because of the $uvm2$ filter that is centered on the bump and the telescope’s ability to resolve nearby stellar populations. When used in combination with optical and infrared imaging, UVOT can provide strong constraints on variations in the extinction law, both from galaxy to galaxy and within individual galaxies, as well as the properties of young stellar populations. Surveys of UVOT have included the Milky Way, the galaxies of the Local Group, the Local Volume Legacy Survey (LVLS) and two deep fields. All of these are being utilized to provide the most detailed information yet about the UV dust attenuation law and the connection of its variation to underlying physical processes as well as the UV properties of hot stars and young stellar populations. Full article

Rectal cancer management has evolved significantly, particularly with neoadjuvant treatment strategies. This narrative review examines the development and effectiveness of these therapies for locally advanced rectal cancer (LARC), highlighting the historical quest that led to current neoadjuvant alternatives. Initially, trials showed the benefits of adding radiotherapy (RT) and chemotherapy (CT) to surgery, reducing local recurrence (LR). The addition of oxaliplatin to chemoradiotherapy (CRT) further improved outcomes. TNT integrates chemotherapy and radiotherapy preoperatively to enhance adherence, timing, and systemic control. Key trials, including PRODIGE 23, CAO/ARO/AIO 12, OPRA, RAPIDO, and STELLAR, are analyzed to compare short-course and long-course RT with systemic chemotherapy. The heterogeneity and difficulty in comparing TNT trials due to different designs and outcomes are acknowledged, along with their promising long-term results. On the other hand, it briefly discusses the potential for non-operative management (NOM) in select patients, a strategy gaining traction due to favorable outcomes in specific trials. As a conclusion, this review underscores the complexity of rectal cancer treatment, emphasizing individualized approaches considering patient preferences and healthcare resources. It also highlights the importance of interpreting impressive positive or negative results with caution due to the variability in study designs and patient populations. Full article

Fluorine is one of the most interesting elements in nuclear astrophysics. Its abundance can provide important hints to constrain the stellar models since fluorine production and destruction are strictly connected to the physical conditions inside the stars. The ${}^{19}\mathrm{F}$(p,α)¹⁶O reaction is one of the fluorine burning processes and the correction evaluation of its reaction rate is of pivotal importance to evaluate the fluorine abundance. Moreover, the ${}^{19}\mathrm{F}$(p,α)¹⁶O reaction rate can have an impact for the production of calcium in the first-generation of Population III stars. Here, we present the AsFiN collaboration efforts to the study of the ${}^{19}\mathrm{F}$(p,$\alpha$)¹⁶O reaction by means of direct and indirect measurements. On the direct measurements side, an experimental campaign aimed to the measurement of the ${}^{19}\mathrm{F}$(p,${\alpha }_{0,\pi }$)¹⁶O reaction is ongoing, taking advantage of the new versatile arrays of silicon strip detectors, LHASA and ELISSA. Moreover, the Trojan Horse Method (THM) was used to determine the ${}^{19}\mathrm{F}$(p,${\alpha }_0$)¹⁶O reaction S(E)-factor in the energy range of astrophysical interest (${\mathrm{E}}_{cm}$≈ 0–1 MeV), showing, for the first time, the presence of resonant structures within the astrophysical energy range. THM has been also applied for the study of the ${}^{19}\mathrm{F}$(p,${\alpha }_{\pi }$)¹⁶O reaction; data analysis is ongoing. Full article

Far-infrared and submillimeter observations have established the fundamental role of dust-obscured star formation in the assembly of stellar mass over the past ∼12 billion years. At z = 2–4, the so-called “cosmic noon”, the bulk of star formation is enshrouded in dust, and dusty star-forming galaxies (DSFGs) contain ∼$50\%$ of the total stellar mass density. Star formation occurs in dense molecular clouds, and is regulated by a complex interplay between all the ISM components that contribute to the energy budget of a galaxy: gas, dust, cosmic rays, interstellar electromagnetic fields, gravitational field, and dark matter. Molecular gas is the actual link between star-forming gas and its complex environment: much of what we know about star formation comes from observations of molecular line emissions. They provide by far the richest information about the star formation process. However, their interpretation requires complex modeling of the astrochemical networks which regulate molecular formation and establish molecular abundances in a cloud, and a modeling of the physical conditions of the gas in which molecular energy levels become populated. This paper critically reviews the main astrochemical parameters needed to obtain predictions about molecular signals in DSFGs. Molecular lines can be very bright compared to the continuum emission, but radiative transfer models are required to properly interpret the observed brightness. We review the current knowledge and the open questions about the interstellar medium of DSFGs, outlining the key role of molecular gas as a tracer and shaper of the star formation process. Full article

This review examines the relationship between black hole activity and kinematic gas–star misalignment in brightest group galaxies (BGGs) with different merger rates. The formation history of galaxy groups is assessed through “age-dating” as an indicator of distinct major mergers involving the BGGs. BGGs within groups characterized by a higher frequency of major mergers are more likely to host active SMBHs. A consistent correlation is identified between the level of black hole activity, as indicated by the 1.4 GHz and 325 MHz radio emissions, and the degree of kinematic misalignment between the gas and stellar components in BGGs. In dynamically fossil groups, where black hole accretion rate is relatively (∼1 dex) lower due to the lack of recent (≤1 Gyr) major mergers, there is reduced (∼30%) misalignment between the gas and stellar components of BGGs compared to non-fossil groups. Additionally, this study reveals that BGGs in non-fossil groups show higher levels of star formation rate and increased occurrence of mergers, contributing to observed color differences. Exploring the properties and dynamics of the gas disk influenced by mechanical AGN feedback through hydrodynamic simulations suggests that AGN wind-induced effects further lead to the persistent gas misalignment in the disk around the supermassive black hole. Full article