52 research outputs found
Early Science with the Large Millimeter Telescope: COOL BUDHIES I - a pilot study of molecular and atomic gas at z~0.2
An understanding of the mass build-up in galaxies over time necessitates
tracing the evolution of cold gas (molecular and atomic) in galaxies. To that
end, we have conducted a pilot study called CO Observations with the LMT of the
Blind Ultra-Deep H I Environment Survey (COOL BUDHIES). We have observed 23
galaxies in and around the two clusters Abell 2192 (z = 0.188) and Abell 963 (z
= 0.206), where 12 are cluster members and 11 are slightly in the foreground or
background, using about 28 total hours on the Redshift Search Receiver (RSR) on
the Large Millimeter Telescope (LMT) to measure the CO J = 1 --> 0
emission line and obtain molecular gas masses. These new observations provide a
unique opportunity to probe both the molecular and atomic components of
galaxies as a function of environment beyond the local Universe. For our sample
of 23 galaxies, nine have reliable detections (S/N3.6) of the CO
line, and another six have marginal detections (2.0 < S/N < 3.6). For the
remaining eight targets we can place upper limits on molecular gas masses
roughly between and . Comparing our results to other
studies of molecular gas, we find that our sample is significantly more
abundant in molecular gas overall, when compared to the stellar and the atomic
gas component, and our median molecular gas fraction lies about above
the upper limits of proposed redshift evolution in earlier studies. We discuss
possible reasons for this discrepancy, with the most likely conclusion being
target selection and Eddington bias.Comment: MNRAS, submitte
In vitro assessment of potential intestinal absorption of some phenolic families and carboxylic acids from commercial instant coffee samples
Coffee is one of the most consumed beverages in the world, being a source of bioactive compunds as well as flavors. Hydroxycinnamic acids, flavonols, and carboxylic acids have been studied in samples of instant coffee commercialized in Spain, The studies about contents of food components should be complemented with either in vitro or in vivo bioaccessibility studies to know the amount of food components effectively available for functions in the human body. In this sense, a widely used in vitro model has been applied to assess the potential intestinal absorption of phenolic compounds and organic acids. Contents of hydroxycinnamic acids and flavonols were higher in instant regular coffee samples than in decaffeinated ones. Bioaccesible phenolic compounds in most analyzed samples account to 20-25 % of hydroxycinnamic acids and 17-26 % of flavonols. This could mean that a great part of them can remain in the gut, acting as potential in situ antioxidants. Quinic, acetic, pyroglutamic, citric and fumaric acids were identified in commercial instant coffee samples. Succininc acid was found in the coffee blend containing chicory. All carboxylic acids showed a very high bioaccesibility. Particularly, acetic acid and quinic acid were found in higher contents in the samples treated with the in vitro simulation of gastrointestinal process, compared to the original ones, which can be explained by their cleavage from chlorogenic acid during digestion. This is considered as a positive effect, since quinic acid is considered as an antioxidant inducer
Quantifying the Detrimental Impacts of Land-Use and Management Change on European Forest Bird Populations
The ecological impacts of changing forest management practices in Europe are poorly understood despite European forests being highly managed. Furthermore, the effects of potential drivers of forest biodiversity decline are rarely considered in concert, thus limiting effective conservation or sustainable forest management. We present a trait-based framework that we use to assess the detrimental impact of multiple land-use and management changes in forests on bird populations across Europe. Major changes to forest habitats occurring in recent decades, and their impact on resource availability for birds were identified. Risk associated with these changes for 52 species of forest birds, defined as the proportion of each species' key resources detrimentally affected through changes in abundance and/or availability, was quantified and compared to their pan-European population growth rates between 1980 and 2009. Relationships between risk and population growth were found to be significantly negative, indicating that resource loss in European forests is an important driver of decline for both resident and migrant birds. Our results demonstrate that coarse quantification of resource use and ecological change can be valuable in understanding causes of biodiversity decline, and thus in informing conservation strategy and policy. Such an approach has good potential to be extended for predictive use in assessing the impact of possible future changes to forest management and to develop more precise indicators of forest health
Early Science with the Large Millimeter Telescope: Constraining the Gas Fraction of a Compact Quiescent Galaxy at z=1.883
We present constraints on the dust continuum flux and inferred gas content of
a gravitationally lensed massive quiescent galaxy at =1.8830.001 using
AzTEC 1.1mm imaging with the Large Millimeter Telescope. MRG-S0851 appears to
be a prototypical massive compact quiescent galaxy, but has evidence that it
experienced a centrally concentrated rejuvenation event in the last 100 Myr
(see Akhshik et al. 2020). This galaxy is undetected in the AzTEC image but we
calculate an upper limit on the millimeter flux and use this to estimate the
H mass limit via an empirically calibrated relation that assumes a constant
molecular gas-to-dust ratio of 150. We constrain the 3 upper limit of
the H fraction from the dust continuum in MRG-S0851 to be
6.8%. MRG-S0851 has a low gas fraction limit with
a moderately low sSFR owing to the recent rejuvenation episode, which together
results in a relatively short depletion time of 0.6 Gyr if no further H
gas is accreted. Empirical and analytical models both predict that we should
have detected molecular gas in MRG-S0851, especially given the rejuvenation
episode; this suggests that cold gas and/or dust is rapidly depleted in at
least some early quiescent galaxies.Comment: 8 pages, 4 figures, accepted for publication in Astrophysical Journal
Letters in January 2021 (in press
Early science with the Large Millimetre Telescope: Deep LMT/AzTEC millimetre observations of Ï” Eridani and its surroundings
Ï” Eridani is a nearby, young Sun-like star that hosts a ring of cool debris analogous to the Solar system's Edgeworth-Kuiper belt. Early observations at (sub-)mm wavelengths gave tentative evidence of the presence of inhomogeneities in the ring, which have been ascribed to the effect of a putative low eccentricity planet, orbiting close to the ring. The existence of these structures has been recently challenged by high-resolution interferometric millimetre observations. Here, we present the deepest single-dish image of Ï” Eridani at millimetre wavelengths, obtained with the Large Millimetre Telescope Alfonso Serrano (LMT). The main goal of these LMT observations is to confirm (or refute) the presence of non-axisymmetric structure in the disc. The dusty ring is detected for the first time along its full projected elliptical shape. The radial extent of the ring is not spatially resolved and shows no evidence, to within the uncertainties, of dust density enhancements. Additional features of the 1.1 mm map are: (i) the presence of significant flux in the gap between the ring and the star, probably providing the first exo-solar evidence of Poynting-Robertson drag, (ii) an unambiguous detection of emission at the stellar positionwith a flux significantly above that expected from Ï” Eridani's photosphere, and (iii) the identification of numerous unresolved sources which could correspond to background dusty star-forming galaxies.This work would have not been possible without the long-term financial support from the Mexican Science and Technology Funding Agency, CONACyT (Consejo Nacional de Ciencia y TecnologĂa) during the construction and operational phase of the Large Millimetre Telescope Alfonso Serrano, as well as support from the US National Science Foundation via the University Radio Observatory program, the Instituto Nacional de AstrofĂsica, Optica y ElectrĂłnica (INAOE) and the University of Massachusetts, Amherst (UMass). MC, EB, FCSM, MO and RLV work was supported by CONACyT research grants SEP-2009-134985 and SEP-2011-169554. GMK is supported by the Royal Society as a Royal Society University Research Fellow. CE is partly supported by Spanish grant AYA2014-55840-P. JPM is supported by a UNSW Vice Chancellor's Postdoctoral Fellowship. SL acknowledges support from CONACyT through grant 238631
Real-world effectiveness of caplacizumab vs the standard of care in immune thrombotic thrombocytopenic purpura
Immune thrombotic thrombocytopenic purpura (iTTP) is a thrombotic microangiopathy caused by anti-ADAMTS13 antibodies. Caplacizumab is approved for adults with an acute episode of iTTP in conjunction with plasma exchange (PEX) and immunosuppression. The objective of this study was to analyze and compare the safety and efficacy of caplacizumab vs the standard of care and assess the effect of the concomitant use of rituximab. A retrospective study from the Spanish TTP Registry of patients treated with caplacizumab vs those who did not receive it was conducted. A total of 155 patients with iTTP (77 caplacizumab, 78 no caplacizumab) were included. Patients initially treated with caplacizumab had fewer exacerbations (4.5% vs 20.5%; P <.05) and less refractoriness (4.5% vs 14.1%; P <.05) than those who were not treated. Time to clinical response was shorter when caplacizumab was used as initial treatment vs caplacizumab used after refractoriness or exacerbation. The multivariate analysis showed that its use in the first 3 days after PEX was associated with a lower number of PEX (odds ratio, 7.5; CI, 2.3-12.7; P <.05) and days of hospitalization (odds ratio, 11.2; CI, 5.6-16.9; P <.001) compared with standard therapy. There was no difference in time to clinical remission in patients treated with caplacizumab compared with the use of rituximab. No severe adverse event was described in the caplacizumab group. In summary, caplacizumab reduced exacerbations and refractoriness compared with standard of care regimens. When administered within the first 3 days after PEX, it also provided a faster clinical response, reducing hospitalization time and the need for PEX
Real-world effectiveness of caplacizumab vs the standard of care in immune thrombotic thrombocytopenic purpura
Immune thrombotic thrombocytopenic purpura (iTTP) is a thrombotic microangiopathy caused by anti-ADAMTS13 antibodies. Caplacizumab is approved for adults with an acute episode of iTTP in conjunction with plasma exchange (PEX) and immunosuppression. The objective of this study was to analyze and compare the safety and efficacy of caplacizumab vs the standard of care and assess the effect of the concomitant use of rituximab. A retrospective study from the Spanish TTP Registry of patients treated with caplacizumab vs those who did not receive it was conducted. A total of 155 patients with iTTP (77 caplacizumab, 78 no caplacizumab) were included. Patients initially treated with caplacizumab had fewer exacerbations (4.5% vs 20.5%; P < .05) and less refractoriness (4.5% vs 14.1%; P < .05) than those who were not treated. Time to clinical response was shorter when caplacizumab was used as initial treatment vs caplacizumab used after refractoriness or exacerbation. The multivariate analysis showed that its use in the first 3 days after PEX was associated with a lower number of PEX (odds ratio, 7.5; CI, 2.3-12.7; P < .05) and days of hospitalization (odds ratio, 11.2; CI, 5.6-16.9; P < .001) compared with standard therapy. There was no difference in time to clinical remission in patients treated with caplacizumab compared with the use of rituximab. No severe adverse event was described in the caplacizumab group. In summary, caplacizumab reduced exacerbations and refractoriness compared with standard of care regimens. When administered within the first 3 days after PEX, it also provided a faster clinical response, reducing hospitalization time and the need for PEX
Early science with the Large Millimeter Telescope: a 1.1 mm AzTEC survey of red-<i>Herschel</i> dusty star-forming galaxies
We present Large Millimeter Telescope (LMT)/AzTEC 1.1âmm observations of âŒ100 luminous high-redshift dusty star-forming galaxy candidates from the âŒ600âsq.deg Herschel-ATLAS survey, selected on the basis of their SPIRE red far-infrared colours and with S500ÎŒm=35â80 mJy. With an effective ΞFWHM â 9.5arcsec angular resolution, our observations reveal that at least 9 perâcent of the targets break into multiple systems with signal-to-noise ratio â„4 members. The fraction of multiple systems increases to âŒ23 perâcent (or more) if some non-detected targets are considered multiples, as suggested by the data. Combining the new AzTEC and deblended Herschel photometry, we derive photometric redshifts, infrared luminosities, and star formation rates. While the median redshifts of the multiple and single systems are similar (zmed â 3.6), the redshift distribution of the latter is skewed towards higher redshifts. Of the AzTEC sources, âŒ85 perâcent lie at zphot > 3 while âŒ33 perâcent are at zphot > 4. This corresponds to a lower limit on the space density of ultrared sources at 4 â7Mpcâ3 with a contribution to the obscured star formation of âł8Ă10â4Mâyrâ1Mpcâ3â . Some of the multiple systems have members with photometric redshifts consistent among them suggesting possible physical associations. Given their angular separations, these systems are most likely galaxy over-densities and/or early-stage pre-coalescence mergers. Finally, we present 3âmm LMT/RSR spectroscopic redshifts of six red-Herschel galaxies at zspec = 3.85â6.03, two of them (at z ⌠4.7) representing new redshift confirmations. Here, we release the AzTEC and deblended Herschel photometry as well as catalogues of the most promising interacting systems and z > 4 galaxies
- âŠ