Institution
National Autonomous University of Mexico
Education•Mexico City, Distrito Federal, Mexico•
About: National Autonomous University of Mexico is a education organization based out in Mexico City, Distrito Federal, Mexico. It is known for research contribution in the topics: Population & Galaxy. The organization has 72868 authors who have published 127797 publications receiving 2285543 citations. The organization is also known as: UNAM & Universidad Nacional Autónoma de México.
Topics: Population, Galaxy, Catalysis, Thin film, Stars
Papers published on a yearly basis
Papers
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Max Planck Society1, INAF2, Harvard University3, Space Telescope Science Institute4, University of California, San Diego5, National Autonomous University of Mexico6, ETH Zurich7, University of Arizona8, University of Bologna9, California Institute of Technology10, University of Hawaii11, Ehime University12, University of Toulouse13, Centre national de la recherche scientifique14, Spanish National Research Council15, University of Padua16
TL;DR: In this article, the authors reported on the measurement of the physical properties (rest-frame K-band luminosity and total stellar mass) of the hosts of 89 broad-line (type-1) active galactic nuclei (AGNs) detected in the zCOSMOS survey in the redshift range 1 < z < 2.
Abstract: We report on the measurement of the physical properties (rest-frame K-band luminosity and total stellar mass) of the hosts of 89 broad-line (type-1) active galactic nuclei (AGNs) detected in the zCOSMOS survey in the redshift range 1 < z < 2.2. The unprecedented multi-wavelength coverage of the survey field allows us to disentangle the emission of the host galaxy from that of the nuclear black hole in their spectral energy distributions (SEDs). We derive an estimate of black hole masses through the analysis of the broad Mg II emission lines observed in the medium-resolution spectra taken with VIMOS/VLT as part of the zCOSMOS project. We found that, as compared to the local value, the average black hole to host-galaxy mass ratio appears to evolve positively with redshift, with a best-fit evolution of the form (1 + z)^[(0.68±0.12)^(+0.6)_(-0.3)], where the large asymmetric systematic errors stem from the uncertainties in the choice of initial mass function, in the calibration of the virial relation used to estimate BH masses and in the mean QSO SED adopted. On the other hand, if we consider the observed rest-frame K-band luminosity, objects tend to be brighter, for a given black hole mass, than those on the local M_(BH)-M_K relation. This fact, together with more indirect evidence from the SED fitting itself, suggests that the AGN hosts are likely actively star-forming galaxies. A thorough analysis of observational biases induced by intrinsic scatter in the scaling relations reinforces the conclusion that an evolution of the M_(BH)-M_* relation must ensue for actively growing black holes at early times: either its overall normalization, or its intrinsic scatter (or both) appear to increase with redshift. This can be interpreted as signature of either a more rapid growth of supermassive black holes at high redshift, a change of structural properties of AGN hosts at earlier times, or a significant mismatch between the typical growth times of nuclear black holes and host galaxies. In any case, our results provide important clues on the nature of the early co-evolution of black holes and galaxies and challenging tests for models of AGN feedback and self-regulated growth of structures.
362 citations
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TL;DR: Small untranslated RNAs (sRNAs) perform a variety of important functions in bacteria, and the discovery of CsrC is intriguing, in that a similar sRNA, CsrB, performs essentially the same function.
Abstract: Small untranslated RNAs (sRNAs) perform a variety of important functions in bacteria. The 245 nucleotide sRNA of Escherichia coli, CsrC, was discovered using a genetic screen for factors that regulate glycogen biosynthesis. CsrC RNA binds multiple copies of CsrA, a protein that post-transcriptionally regulates central carbon flux, biofilm formation and motility in E. coli. CsrC antagonizes the regulatory effects of CsrA, presumably by sequestering this protein. The discovery of CsrC is intriguing, in that a similar sRNA, CsrB, performs essentially the same function. Both sRNAs possess similar imperfect repeat sequences (18 in CsrB, nine in CsrC), primarily localized in the loops of predicted hairpins, which may serve as CsrA binding elements. Transcription of csrC increases as the culture approaches the stationary phase of growth and is indirectly activated by CsrA via the response regulator UvrY. Because CsrB and CsrC antagonize CsrA activity and depend on CsrA for their synthesis, a csrB null mutation causes a modest compensatory increase in CsrC levels and vice versa. Homologues of csrC are apparent in several Enterobacteriaceae. The regulatory and evolutionary implications of these findings are discussed.
362 citations
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TL;DR: In this article, the authors quantified aboveground biomass as well as aboveground and mineral soil C, N, S, and P pools in 11 secondary forest sites in the Los Tuxtlas Region of Mexico.
Abstract: Tropical secondary forests have the capacity to function as large carbon and nutrient sinks and may offset losses resulting from deforestation and land use. In the heavily deforested Los Tuxtlas Region of Mexico, aboveground biomass as well as aboveground and mineral soil C, N, S, and P pools were quantified in 11 secondary forest sites. These sites ranged in age from 6 mo to 50 yr following abandonment and had experienced between 1 and 30 yr of land use prior to abandonment. Total aboveground biomass (TAGB) increased with increasing site age and ranged from 4.8 Mg/ha in a recently abandoned site to 287 Mg/ha in the 50-yr-old secondary forest site. Results indicate that secondary forests would reach TAGB levels equivalent to those of primary forests in the Los Tuxtlas Region after 73 yr. Furthermore, mean annual aboveground biomass accumulation (ABA) of secondary forests was strongly and inversely related to the duration of prior land use. Aboveground pools of C, N, S, and P were also positively correlate...
362 citations
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Goddard Space Flight Center1, Massachusetts Institute of Technology2, Carnegie Institution for Science3, Pierre-and-Marie-Curie University4, National Autonomous University of Mexico5, Jacobs Engineering Group6, Stony Brook University7, California Institute of Technology8, Imperial College London9, University of California, Davis10, Supélec11, Paris Diderot University12
TL;DR: In situ detection of organic matter preserved in lacustrine mudstones at the base of the ~3.5-billion-year-old Murray formation at Pahrump Hills, Gale crater, by the Sample Analysis at Mars instrument suite onboard the Curiosity rover is reported.
Abstract: Establishing the presence and state of organic matter, including its possible biosignatures, in martian materials has been an elusive quest, despite limited reports of the existence of organic matter on Mars. We report the in situ detection of organic matter preserved in lacustrine mudstones at the base of the ~3.5-billion-year-old Murray formation at Pahrump Hills, Gale crater, by the Sample Analysis at Mars instrument suite onboard the Curiosity rover. Diverse pyrolysis products, including thiophenic, aromatic, and aliphatic compounds released at high temperatures (500° to 820°C), were directly detected by evolved gas analysis. Thiophenes were also observed by gas chromatography–mass spectrometry. Their presence suggests that sulfurization aided organic matter preservation. At least 50 nanomoles of organic carbon persists, probably as macromolecules containing 5% carbon as organic sulfur molecules.
362 citations
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TL;DR: It is demonstrated that the extracts of Aloe vera gel have antiinflammatory activity and suggested its inhibitory action on the arachidonic acid pathway via cyclooxygenase.
361 citations
Authors
Showing all 73617 results
Name | H-index | Papers | Citations |
---|---|---|---|
Richard Peto | 183 | 683 | 231434 |
Anton M. Koekemoer | 168 | 1127 | 106796 |
Rory Collins | 162 | 489 | 193407 |
Timothy C. Beers | 156 | 934 | 102581 |
Vivek Sharma | 150 | 3030 | 136228 |
Kjell Fuxe | 142 | 1479 | 89846 |
Prashant V. Kamat | 140 | 725 | 79259 |
Carmen García | 139 | 1503 | 96925 |
Harold A. Mooney | 135 | 450 | 100404 |
Efe Yazgan | 128 | 986 | 79041 |
Roberto Maiolino | 127 | 816 | 61724 |
Peter Nugent | 127 | 754 | 92988 |
William R. Miller | 125 | 601 | 72570 |
Nicholas A. Kotov | 123 | 574 | 55210 |
John C. Wingfield | 122 | 509 | 52291 |