| 1. |
- Fujimoto, Seiji, et al.
(författare)
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ALMA Lensing Cluster Survey: Bright [C ii] 158 mu m Lines from a Multiply Imaged Sub-L* Galaxy at z=6.0719
- 2021
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 1538-4357 .- 0004-637X. ; 911:2
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Forskningsöversikt (refereegranskat)abstract
- We present bright [C ii] 158 mu m line detections from a strongly magnified and multiply imaged (mu similar to 20-160) sub-L* (MUV=-19.75-0.44+0.55) Lyman-break galaxy (LBG) at z = 6.0719 +/- 0.0004, drawn from the ALMA Lensing Cluster Survey (ALCS). Emission lines are identified at 268.7 GHz at >= 8 sigma exactly at the positions of two multiple images of the LBG, behind the massive galaxy cluster RXCJ0600-2007. Our lens models, updated with the latest spectroscopy from VLT/MUSE, indicate that a sub region of the LBG crosses the caustic, and is lensed into a long (similar to 6 '') arc with a local magnification of mu similar to 160, for which the [C ii] line is also significantly detected. The source plane reconstruction resolves the interstellar medium (ISM) structure, showing that the [C ii] line is co-spatial with the rest-frame UV continuum at a scale of similar to 300 pc. The [C ii] line properties suggest that the LBG is a rotation-dominated system, whose velocity gradient explains a slight difference in redshifts between the whole LBG and its sub-region. The star formation rate (SFR)-L-[CII] relations, for whole and sub-regions of the LBG, are consistent with those of local galaxies. We evaluate the lower limit of the faint-end of the [C ii] luminosity function at z = 6, finding it to be consistent with predictions from semi-analytical models and from the local SFR-L-[CII] relation with a SFR function at z = 6. These results imply that the local SFR-L-[CII] relation is universal for a wide range of scales, including the spatially resolved ISM, the whole region of the galaxy, and the cosmic scale, even in the epoch of reionization.
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| 2. |
- Fujimoto, Seiji, et al.
(författare)
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JWST and ALMA Multiple-line Study in and around a Galaxy at z =8.496: Optical to Far-Infrared Line Ratios and the Onset of an Outflow Promoting Ionizing Photon Escape
- 2024
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Ingår i: Astrophysical Journal. - 1538-4357 .- 0004-637X. ; 964:2
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Tidskriftsartikel (refereegranskat)abstract
- We present Atacama Large Millimeter/submillimeter Array (ALMA) deep spectroscopy for a lensed galaxy at z(spec) = 8.496 with log(M-star/M-circle dot) similar to 7.8 whose optical nebular lines and stellar continuum are detected by JWST/NIRSpec and NIRCam Early Release Observations in the field of SMACS J0723.3-7327. Our ALMA spectrum shows [O III] 88 mu m and [C II] 158 mu m line detections at 4.0 sigma and 4.5 sigma, respectively. The redshift and position of the [O III] line coincide with those of the JWST source, while the [C II] line is blueshifted by 90 km s(-1) with a spatial offset of 0.'' 5 (approximate to 0.5 kpc in the source plane) from the centroid of the JWST source. The NIRCam F444W image, including [O III] lambda 5007 and H beta line emission, spatially extends beyond the stellar components by a factor of >8. This indicates that the z = 8.5 galaxy has already experienced strong outflows as traced by extended [O III] lambda 5007 and offset [C II] emission, which would promote ionizing photon escape and facilitate reionization. With careful slit-loss corrections and the removal of emission spatially outside the galaxy, we evaluate the [O III] 88 mu m/lambda 5007 line ratio, and derive the electron density n (e) by photoionization modeling to be 220(-130)(+230) cm(-3), which is comparable with those of z similar to 2-3 galaxies. We estimate an [O III] 88 mu m/[C II] 158 mu m line ratio in the galaxy of >4, as high as those of known z similar to 6-9 galaxies. This high [O III] 88 mu m/[C II] 158 mu m line ratio is generally explained by the high n(e) as well as the low metallicity (Z(gas)/Z(circle dot)=0.04(-0.02)(+0.02)), high ionization parameter (log U > -2.27), and low carbon-to-oxygen abundance ratio (log(C/O) = [-0.52: -0.24]) obtained from the JWST/NIRSpec data; further [C II] follow-up observations will constrain the covering fraction of photodissociation regions.
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| 3. |
- Jolly, Jean Baptiste, 1990, et al.
(författare)
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ALMA Lensing Cluster Survey: A spectral stacking analysis of [C II] in lensed z similar to 6 galaxies
- 2021
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 652
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Tidskriftsartikel (refereegranskat)abstract
- Context. The properties of galaxies at redshift z>6 hold the key to our understanding of the early stages of galaxy evolution and can potentially identify the sources of the ultraviolet radiation that give rise to the epoch of reionisation. The far-infrared cooling line of [C II] at 158 mu m is known to be bright and correlate with the star formation rate (SFR) of low-redshift galaxies, and hence is also suggested to be an important tracer of star formation and interstellar medium properties for very high-redshift galaxies. Aims. With the aim to study the interstellar medium properties of gravitationally lensed galaxies at z>6, we search for [C II] and thermal dust emission in a sample of 52 > 6 galaxies observed by the ALMA Lensing Cluster Survey. Methods. We perform our analysis using LINESTACKER, stacking both [C II] and continuum emission. The target sample is selected from multiple catalogues, and the sample galaxies have spectroscopic redshift or low-uncertainty photometric redshifts (sigma(z)<0.02) in nine galaxy clusters. Source properties of the target galaxies are either extracted from the literature or computed using spectral energy distribution fitting. Both weighted-average and median stacking are used, on both the full sample and three sub-samples. Results. Our analyses find no detection of either [C II] or continuum. An upper limit on L-[CII] is derived, implying that [C II] remains marginally consistent for low-SFR z>6 galaxies but likely is under-luminous compared to the local L-[CII]-SFR relationship. We discuss potential biases and possible physical effects that may be the cause of the non-detection. Further, the upper limit on the dust continuum implies that less than half of the star formation is obscured.
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| 4. |
- Lazaridis, Iosif, et al.
(författare)
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Ancient human genomes suggest three ancestral populations for present-day Europeans
- 2014
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 513:7518, s. 409-
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Tidskriftsartikel (refereegranskat)abstract
- We sequenced the genomes of a similar to 7,000-year-old farmer from Germany and eight similar to 8,000-year-old hunter-gatherers from Luxembourg and Sweden. We analysed these and other ancient genomes(1-4) with 2,345 contemporary humans to show that most present-day Europeans derive from at least three highly differentiated populations: west European hunter-gatherers, who contributed ancestry to all Europeans but not to Near Easterners; ancient north Eurasians related to Upper Palaeolithic Siberians(3), who contributed to both Europeans and Near Easterners; and early European farmers, who were mainly of Near Eastern origin but also harboured west European hunter-gatherer related ancestry. We model these populations' deep relationships and show that early European farmers had similar to 44% ancestry from a 'basal Eurasian' population that split before the diversification of other non-African lineages.
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| 5. |
- Micolucci, Federico, et al.
(författare)
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Pilot-scale multi-purposes approach for volatile fatty acid production, hydrogen and methane from an automatic controlled anaerobic process
- 2020
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Ingår i: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526. ; 277
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Tidskriftsartikel (refereegranskat)abstract
- A combined two-levels control method has been developed and tested on a long term operation of a two-phases pilot-scale anaerobic process for the concurrent production of volatile fatty acids, hydrogen and methane. The latter was designed for the treatment of food waste of urban origin (namely, the organic fraction of municipal solid waste). The optimized control method was set on the base of the inputs of three online probes: a pH-meter in the fermentation reactor, a pH-meter and a conductivity probe in the digestion reactor. The first control level managed the pH in the fermentation reactor while the second control level managed the ammonia concentration in the digestion reactor. This combination established the volume of the digestate to be recycled from the digestion to the fermentation reactor, optimizing the yield of volatile fatty acid (0.31–0.32 kg CODVFA/kg CODfed) and the specific hydrogen production (SHP; 0.070–0.074 m3 H2/kg TVSfed) in the fermentation reactor and the specific methane production (SMP; 0.48–0.55 m3 CH4/kg TVSfed) in the digestion reactor. A new process configuration was also proposed and applied over the course of the long operation period. This configuration allowed to remove part of the volatile fatty acid-rich liquid stream from the fermenter effluent, maintaining the corresponding solid-rich effluent in the whole system (as feed for the digestion reactor) by using a solid/liquid separation unit. In this way, the concentration of volatile fatty acids in the digester was kept at a low level, even with high loading rates, so maintaining a satisfying efficiency of methane production and utilizing the excess volatile fatty acids (out of the system) as building blocks for other purposes. The optimized two-levels control method for the anaerobic treatment of food waste provides new perspectives for the valorisation of such waste stream; the production of building blocks namely volatile fatty acids supports new innovative bio-refinery platforms for the production of bio-products.
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| 6. |
- Morgan-Sagastume, Fernando, et al.
(författare)
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Acclimation Process for Enhancing Polyhydroxyalkanoate Accumulation in Activated-Sludge Biomass
- 2019
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Ingår i: Waste and Biomass Valorization. - : Springer. - 1877-2641 .- 1877-265X. ; 10:4, s. 1065-1082
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Tidskriftsartikel (refereegranskat)abstract
- A strategy was evaluated for conditioning activated sludge biomass to a new substrate whereby the polyhydroxyalkanoate (PHA) accumulation capacity of the biomass was enhanced based on a series of aerobic feast–famine acclimation cycles applied prior to PHA accumulation. Different biomass types enriched during the treatment of municipal wastewater at laboratory, pilot, and full scales were exposed to aerobic feast–famine acclimation cycles at different feast-to-famine ratios with an acetate–propionate mixture (laboratory scale), acetate (pilot scale), and fermented waste–sludge centrate (pilot scale). A sevenfold increase in specific PHA storage rates and 20% increase in substrate utilization rates were observed during acclimation cycles (laboratory acetate–propionate). Biomass acclimation led to more than doubling of the specific substrate utilization rates, PHA storage rates, biomass PHA contents, and specific PHA productivities (per initial biomass) during PHA accumulation. The biomass PHA contents were found to increase due to acclimation from 0.19 to 0.34 (laboratory acetate–propionate), 0.39 to 0.46 (pilot acetate) and 0.19 to 0.25 gPHA/gVSS (pilot centrate). A similar bacterial community structure during acclimation indicated that a physiological rather than a genotypic adaptation occurred in the biomass. The physiological state of the biomass at the start of PHA accumulation was deemed significant in the subsequent PHA-accumulation performance. Positive acclimation trends can be monitored by measuring the relative increase in feast substrate utilization or respiration rates with respect to those of the first acclimation cycle.
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| 7. |
- Najafi, Leyla, et al.
(författare)
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Hybrid Organic/Inorganic Photocathodes Based on WS2 Flakes as Hole Transporting Layer Material
- 2021
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Ingår i: Small Structures. - : John Wiley & Sons. - 2688-4062. ; 2:3
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Tidskriftsartikel (refereegranskat)abstract
- The efficient production of molecular hydrogen (H2) is a fundamental step toward an environmentally friendly economy. Photocathodes using organic bulk heterojunction (BHJ) films as light harvesters represent an attracting technology for low-cost photoelectrochemical water splitting. These photocathodes need charge transporting layers (CTLs) to efficiently separate and transport either holes or electrons toward the back-current collector and electrolyte, respectively. Therefore, it is pivotal to control the energy band edge levels and the work function (WF) of the CTLs to match the ones of the BHJ film, current collector, and electrolyte. Herein, the use of 2D p-doped WS2 flakes as hole transporting material for H2-evolving photocathodes based on the regioregular poly(3-hexylthiophene):phenyl-C61-butyric acid methyl ester (rr-P3HT:PCBM) BHJ film is proposed. The WS2 flakes are produced through scalable liquid-phase exfoliation of the bulk crystal, whereas p-type chemical doping allows the tuning of the WS2 WF. This approach boosts the performances of the photocathodes, reaching photocurrent densities up to 4.14 mA cm−2 at 0 V versus reversible hydrogen electrode (RHE), an onset potential of 0.66 V versus RHE, and a ratiometric power-saved metric of 1.28% (under 1 sun illumination). To the best of the authors' knowledge, these performances represent the current record for 2D materials-based CTLs.
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| 8. |
- Pironi, Loris, et al.
(författare)
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Characteristics of adult patients with chronic intestinal failure due to short bowel syndrome: An international multicenter survey
- 2021
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Ingår i: Clinical Nutrition ESPEN. - : Elsevier BV. - 2405-4577. ; 45, s. 433-441
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Tidskriftsartikel (refereegranskat)abstract
- Background and aims: The case-mix of patients with intestinal failure due to short bowel syndrome (SBS-IF) can differ among centres and may also be affected by the timeframe of data collection. Therefore, the ESPEN international multicenter cross-sectional survey was analyzed to compare the characteristics of SBS-IF cohorts collected within the same timeframe in different countries. Methods: The study included 1880 adult SBS-IF patients collected in 2015 by 65 centres from 22 countries. The demographic, nutritional, SBS type (end jejunostomy, SBS-J; jejuno-colic anastomosis, SBS-JC; jejunoileal anastomosis with an intact colon and ileocecal valve, SBS-JIC), underlying disease and intravenous supplementation (IVS) characteristics were analyzed. IVS was classified as fluid and electrolyte alone (FE) or parenteral nutrition admixture (PN). The mean daily IVS volume, calculated on a weekly basis, was categorized as <1, 1–2, 2–3 and >3 L/day. Results: In the entire group: 60.7% were females and SBS-J comprised 60% of cases, while mesenteric ischaemia (MI) and Crohn’ disease (CD) were the main underlying diseases. IVS dependency was longer than 3 years in around 50% of cases; IVS was infused ≥5 days/week in 75% and FE in 10% of cases. Within the SBS-IF cohort: CD was twice and thrice more frequent in SBS-J than SBS-JC and SBS-JIC, respectively, while MI was more frequent in SBS-JC and SBS-JIC. Within countries: SBS-J represented 75% or more of patients in UK and Denmark and 50-60% in the other countries, except Poland where SBS-JC prevailed. CD was the main underlying disease in UK, USA, Denmark and The Netherlands, while MI prevailed in France, Italy and Poland. Conclusions: SBS-IF type is primarily determined by the underlying disease, with significant variation between countries. These novel data will be useful for planning and managing both clinical activity and research studies on SBS.
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| 9. |
- Valentino, Francesco, et al.
(författare)
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Organic Fraction of Municipal Solid Waste Recovery by Conversion into Added-Value Polyhydroxyalkanoates and Biogas
- 2018
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Ingår i: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 6:12, s. 16375-16385
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Tidskriftsartikel (refereegranskat)abstract
- The integrated-multistage process proposed herein is a practical example of a biorefinery platform in which the organic fraction of municipal solid waste (OFMSW) is used as a valued source for polyhydroxyalkanoates (PHA) and biogas production. Technical and economical feasibilities of this approach have been demonstrated at pilot-scale, providing a possible upgrade to traditional biowaste management practices, presently based on anaerobic digestion (AD). A pH-controlled OFMSW fermentation stage produced a liquid VFA-rich stream with a high VFA/CODSOL ratio (0.90 COD/COD) that was easily used in the following aerobic stages for biomass and PHA production. The solid fraction was valorized into biogas through AD, obtaining energy and minimizing secondary flux waste generation. The reliable biomass enrichment was demonstrated by a stable feast-famine regime and supported by microbial community analysis. The selected consortium accumulated PHA up to 55% wt. Compared to the traditional AD process in an urban scenario of 900000 AE, the integrated approach for OFMSW valorization is preferable, and it is characterized by an electrical energy production of 85.7 MWh/d and 1.976 t/d as PHA productivity. The proposed process was also evaluated as economically sustainable if the PHA is marketed from 0.90 €/kg as the minimum threshold to a higher market price.
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