14 research outputs found
Mobilising post-political environments : tracing the selective geographies of Swedish sustainable urban development
No full textThis paper develops an analytical framework from which to understand the mobilisation of post-political urban environments across spatial and institutional contexts. Our analysis of two closely related cases from a Swedish context reveals the potential benefits of combining studies on urban political ecology and policy mobility. By utilising Actor-Network Theory (ANT) we illustrate how post-political environments that are shaped by mobile and mutating policies of sustainable urban development are stabilised through distinct discursive strategies, capital investments and the desire for increased influence within global frames of action and contribute to the creation of, what we call, selective geographies
A
No full textAims. We leverage the largest available Atacama Large Millimeter/submillimeter Array (ALMA) survey from the archive (A3COSMOS) to study infrared luminosity function and dust-obscured star formation rate density of (sub)millimeter galaxies from z = 0.5 − 6.
Methods. The A3COSMOS survey utilizes all publicly available ALMA data in the COSMOS field and therefore has inhomogeneous coverage in terms of observing wavelength and depth. In order to derive the luminosity functions and star formation rate densities, we applied a newly developed method that corrects the statistics of an inhomogeneously sampled survey of individual pointings to those representing an unbiased blind survey.
Results. We find our sample to mostly consist of massive (M⋆ ∼ 1010 − 1012 M⊙) IR-bright (L* ∼ 1011 − 1013.5 L⊙) highly star-forming (SFR ∼100 − 1000 M⊙
yr−1) galaxies. We find an evolutionary trend in the typical density (Φ*) and luminosity (L*) of the galaxy population that respectively decreases and increases with redshift. Our infrared luminosity function (LF) is in agreement with previous literature results, and we were able to extend the constraints on the knee and bright end of the LF to high redshift (z > 3) by using the Herschel data. Finally, we obtained the star formation rate density up to z ∼ 6 by integrating the IR LF, finding a broad peak from z ∼ 1 to z ∼ 3 and a decline toward higher redshifts, in agreement with recent IR/millimeter-based studies, within the uncertainties. These results imply the presence of larger quantities of dust than what is expected based on optical/UV studies
Dust emission from the bulk of galaxies in the Epoch of Reionisation
No full textThe excess of UV-bright galaxies observed at z > 10 has been one of the major surprises of the early JWST observations. Several explanations have been proposed to understand the mild change in space density of the UV-bright galaxies at these high redshifts, among them an evolution of dust attenuation properties in galaxies. However, our view of dust in primordial galaxies is limited towards a few tens of z ∼ 7 galaxies, pre-selected from UV-optical observations, and are thus not necessarily representative of the bulk of the sources at these redshifts. In this work, we aim to constrain the dust properties of galaxies at 6 9) at 6 −19 mag), lower-mass sources (logM⋆/M⊙ 7). Fitting these 6 8, compared to the fit without FIR. We extend the LIR vs MUV relation down to MUV = −19 mag and show a tentative breakdown of the relation at fainter UV magnitudes. The positions of the JADES z ∼ 6.5 sample on the infrared excess (IRX) versus β and IRX versus M⋆ diagrams are consistent with the ones of the ALPINE (z ∼ 5.5) and REBELS (z ∼ 6.5) samples, suggesting that the dust composition and content of our mass-selected sample are similar to the ones of these UV-selected galaxies. Extending our analysis of the infrared properties to z > 7 galaxies, we find a non-evolution of β in the MUV range probed by our sample (–17.24), and highlight the fact that samples from the literature are not representative of the bulk of galaxy populations at z > 6. We confirm a linear relation between AV and sSFR−1 with a flatter slope than previously reported due to the use of ALMA constraints. Our results suggest that rapid and significant dust production has already happened by z ∼ 7
ACOSMOS: Dissecting the gas content of star-forming galaxies across the main sequence at 1.2 < 1.6
No full textWe aim to understand the physical mechanisms that drive star formation in a
sample of mass-complete (>10) star-forming galaxies (SFGs) at
1.2 < 1.6. We selected SFGs from the COSMOS2020 catalog and applied a
-domain stacking analysis to their archival Atacama Large
Millimeter/submillimeter Array (ALMA) data. Our stacking analysis provides
precise measurements of the mean molecular gas mass and size of SFGs. We also
applied an image-domain stacking analysis on their \textit{HST} -band and
UltraVISTA - and -band images. Correcting these rest-frame
optical sizes using the -to- conversion at rest 5,000 angstrom, we obtain the stellar
mass size of MS galaxies. Across the MS (-0.2 < MS < 0.2), the mean
molecular gas fraction of SFGs increases by a factor of 1.4, while their
mean molecular gas depletion time decreases by a factor of 1.8. The
scatter of the MS could thus be caused by variations in both the star formation
efficiency and molecular gas fraction of SFGs. The majority of the SFGs lying
on the MS have . Their central regions
are subject to large dust attenuation. Starbursts (SBs, MS>0.7) have a
mean molecular gas fraction 2.1 times larger and mean molecular gas
depletion time 3.3 times shorter than MS galaxies. Additionally, they
have more compact star-forming regions (2.5~kpc for MS galaxies vs.
1.4~kpc for SBs) and systematically disturbed rest-frame optical
morphologies, which is consistent with their association with major-mergers.
SBs and MS galaxies follow the same relation between their molecular gas mass
and star formation rate surface densities with a slope of , that
is, the so-called KS relation.Comment: 20 pages, 17 figure
A3COSMOS & A3GOODSS: Continuum Source Catalogues and Multi-band Number Counts
No full textInternational audienceGalaxy submillimetre number counts are a fundamental measurement in our understanding of galaxy evolution models. Most early measurements are obtained via single-dish telescopes with substantial source confusion, whereas recent interferometric observations are limited to small areas. We used a large database of ALMA continuum observations to accurately measure galaxy number counts in multiple (sub)millimetre bands, thus bridging the flux density range between single-dish surveys and deep interferometric studies. We continued the Automated Mining of the ALMA Archive in the COSMOS Field project (A3COSMOS) and extended it with observations from the GOODS-South field (A3GOODSS). The database consists of ~4,000 pipeline-processed continuum images from the public ALMA archive, yielding 2,050 unique detected sources. To infer galaxy number counts, we constructed a method to reduce the observational bias inherent to targeted pointings that dominate the database. This method comprises a combination of image selection, masking, and source weighting. The effective area was calculated by accounting for inhomogeneous wavelengths, sensitivities, and resolutions and for spatial overlap between images. We tested and calibrated our method with simulations. We obtained the first number counts derived in a consistent and homogeneous way in four different ALMA bands covering a relatively large area. The results are consistent with number counts from the literature within the uncertainties. We extended the available depth in ALMA Band 4 by 0.4 dex with respect to previous studies. In Band 7, at the depth of the inferred number counts, ~40% of the cosmic infrared background is resolved into discrete sources. This fraction, however, decreases with wavelength, reaching ~4% in Band 3. Finally, we used the number counts to test models of dusty galaxy evolution, and find a good agreement within the uncertainties
A
No full textAims. We aim to understand the physical mechanisms that drive star formation in a sample of mass-complete (>109.5 M⊙) star-forming galaxies (SFGs) at 1.2 ≤ ɀ < 1.6.
Methods. We selected SFGs from the COSMOS2020 catalog and applied a uυ-domain stacking analysis to their archival Atacama Large Millimeter/submillimeter Array (ALMA) data. Our stacking analysis provides precise measurements of the mean molecular gas mass and size of SFGs down to a stellar mass of M★ ~ 109.5 M⊙, even though at these stellar mass galaxies on the main sequence (MS) are no longer detected individually in the archival ALMA data. We also applied an image-domain stacking analysis on their HST i-band and UltraVISTA J - and Ks-band images. This allowed us to trace the distribution of their stellar component. Correcting these rest-frame optical sizes using the Rhalf–stellar–light-to-Rhalf–stellar–mass conversion at rest 5000 Å, we obtain the stellar mass size of MS galaxies and compare them to the sizes of their star-forming component obtained from our ALMA stacking analysis.
Results. Across the MS (−0.2 0.7) have a mean molecular gas fraction ~2.1 times larger and mean molecular gas depletion time ~3.3 times shorter than MS galaxies. Additionally, they have more compact star-forming regions (~2.5 kpc for MS galaxies vs. ~1.4 kpc for SBs) and systematically disturbed rest-frame optical morphologies, which is consistent with their association with major-mergers. SBs and MS galaxies follow the same relation between their molecular gas mass and star formation rate surface densities with a slope of ~ 1.1–1.2, that is, the so-called Kennicutt-Schmidt relation
Scalable Manufacturing Method for Model Protein-Loaded PLGA Nanoparticles: Biocompatibility, Trafficking and Release Properties
No full textBackground and Objectives: Drug delivery systems (DDSs) offer efficient treatment solutions to challenging diseases such as central nervous system (CNS) diseases
by bypassing biological barriers such as the blood–brain barrier (BBB). Among DDSs,
polymeric nanoparticles (NPs), particularly poly(lactic-co-glycolic acid) (PLGA) NPs, hold
an outstanding position due to their biocompatible and biodegradable qualities. Despite
their potential, the translation of PLGA NPs from laboratory-scale production to clinical
applications remains a significant challenge. This study aims to address these limitations
by developing scalable PLGA NPs and evaluating their potential biological applications.
Methods: We prepared blank and model-protein-loaded (albumin–FITC and wheat germ
agglutinin-488 (WGA-488)) fluorescent PLGA NPs using the traditional double-emulsion
method combined with the micro-spray-reactor system, a novel approach that enables
fine particle production enabling scale-up applications. We tested the biocompatibility
of the NPs in living RPMI 2650 and neuroblastoma cell lines, as well as their trafficking
and uptake. Release kinetics of the encapsulated proteins were investigated through confocal microscopy and in vitro release studies, providing insights into the stability and
functionality of the released proteins. Results: The formulation demonstrated sustained
and prolonged protein release profiles. Importantly, cellular uptake studies revealed that
the NPs were not internalized. Furthermore, encapsulated WGA-488 protein retained
its functional activity after release, validating the integrity of the encapsulation and release processes. Conclusions: The proof-of-concept study on NP manufacturing and an
innovative drug trafficking and release approach can bring new perspectives on scalable
preparations of PLGA NPs and their biological applications
The gas mass reservoir of quiescent galaxies at cosmic noon
No full textWe present a 1.1 mm stacking analysis of moderately massive (log(M*/M⊙) = 10.7 ± 0.2) quiescent galaxies (QGs) at ⟨z⟩∼1.5, searching for cold dust continuum emission, which serves as an excellent tracer of dust and gas mass. Using both the recent GOODS-ALMA survey, as well as the full suite of ALMA Band-6 ancillary data in the GOODS-S field, we report the tentative detection of a dust continuum equivalent of the dust mass log(Mdust/M⊙) = 7.47 ± 0.13 and gas mass log(Mgas/M⊙) = 9.42 ± 0.14. The emerging gas fraction is fgas = 5.3 ± 1.8%, consistent with the results of previous stacking analyses based on lower resolution sub(mm) observations. Our results support the scenario where high-z QGs exhibit a larger fgas value by one order of magnitude compared to their local counterparts and have experienced quenching with a non-negligible gas reservoir in their interstellar medium, namely, with gas retention. Our subsequent analysis yields an anti-correlation between the fgas and the stellar mass of QGs, especially in the high-mass end where galaxies reside in the most massive halos. The fgas − M* anti-correlation promotes the selection bias as a possible solution to the tension between the stacking results pointing towards gas retention in high-z QGs of moderate M* and studies of individual targets that favour a fully depleted ISM in massive (log(M*/M⊙) > 11.2) high-z QGs
Scalable Manufacturing Method for Model Protein-Loaded PLGA Nanoparticles: Biocompatibility, Trafficking and Release Properties
No full textBackground and Objectives: Drug delivery systems (DDSs) offer efficient treatment solutions to challenging diseases such as central nervous system (CNS) diseases by bypassing biological barriers such as the blood–brain barrier (BBB). Among DDSs, polymeric nanoparticles (NPs), particularly poly(lactic-co-glycolic acid) (PLGA) NPs, hold an outstanding position due to their biocompatible and biodegradable qualities. Despite their potential, the translation of PLGA NPs from laboratory-scale production to clinical applications remains a significant challenge. This study aims to address these limitations by developing scalable PLGA NPs and evaluating their potential biological applications. Methods: We prepared blank and model-protein-loaded (albumin–FITC and wheat germ agglutinin-488 (WGA-488)) fluorescent PLGA NPs using the traditional double-emulsion method combined with the micro-spray-reactor system, a novel approach that enables fine particle production enabling scale-up applications. We tested the biocompatibility of the NPs in living RPMI 2650 and neuroblastoma cell lines, as well as their trafficking and uptake. Release kinetics of the encapsulated proteins were investigated through confocal microscopy and in vitro release studies, providing insights into the stability and functionality of the released proteins. Results: The formulation demonstrated sustained and prolonged protein release profiles. Importantly, cellular uptake studies revealed that the NPs were not internalized. Furthermore, encapsulated WGA-488 protein retained its functional activity after release, validating the integrity of the encapsulation and release processes. Conclusions: The proof-of-concept study on NP manufacturing and an innovative drug trafficking and release approach can bring new perspectives on scalable preparations of PLGA NPs and their biological applications
