Now showing items 8318-8337 of 13761

    • Probing the Full CO Spectral Line Energy Distribution (SLED) in the Nuclear Region of a Quasar-starburst System at z = 6.003

      Li, Jianan; Wang, Ran; Riechers, Dominik; Walter, Fabian; Decarli, Roberto; Venamans, Bram P.; Neri, Roberto; Shao, Yali; Fan, Xiaohui; Gao, Yu; et al. (IOP PUBLISHING LTD, 2020-02-04)
      We report Atacama Large Millimeter/submillimeter Array observations of CO(8-7), (9-8), H2O(2(0,2)-1(1,1)), and OH+(1(1)-0(1)) and NOrthern Extended Millimeter Array observations of CO(5-4), (6-5), (12-11), and (13-12) toward the z.=.6.003 quasar SDSS J231038.88+185519.7, aiming to probe the physical conditions of the molecular gas content of this source. We present the best sampled CO spectral line energy distribution (SLED) at z.=.6.003, and analyzed it with the radiative transfer code MOLPOP-CEP. Fitting the CO SLED to a one-component model indicates a kinetic temperature T-kin=.228 K, molecular gas density log(n(H-2) cm(-3)).=.4.75, and CO column density log(N (CO) cm(-2)) = 17.5; although, a two-component model better fits the data. In either case, the CO SLED is dominated by a "warm" and "dense" component. Compared to samples of local (Ultra) Luminous Infrared Galaxies, starburst galaxies, and high-redshift submillimeter galaxies, J2310+1855 exhibits higher CO excitation at (J >= 8), like other high-redshift quasars. The high CO excitation, together with the enhanced L-H2O/L-IR, L-H2O/L-CO, and LOH+/L-H2O ratios, suggests that besides the UV radiation from young massive stars, other mechanisms such as shocks, cosmic-rays, and X-rays might also be responsible for the heating and ionization of the molecular gas. In the nuclear region probed by the molecular emissions lines, any of these mechanisms might be present due to the powerful quasar and the starburst activity.
    • Probing the Gravitational Dependence of the Fine-Structure Constant from Observations of White Dwarf Stars

      Bainbridge, Matthew; Barstow, Martin; Reindl, Nicole; Tchang-Brillet, W.-Ü; Ayres, Thomas; Webb, John; Barrow, John; Hu, Jiting; Holberg, Jay; Preval, Simon; et al. (MDPI AG, 2017-03-30)
      Hot white dwarf stars are the ideal probe for a relationship between the fine-structure constant and strong gravitational fields, providing us with an opportunity for a direct observational test. We study a sample of hot white dwarf stars, combining far-UV spectroscopic observations, atomic physics, atmospheric modelling, and fundamental physics in the search for variation in the fine structure constant. This variation manifests as shifts in the observed wavelengths of absorption lines, such as quadruply ionized iron (FeV) and quadruply ionized nickel (NiV), when compared to laboratory wavelengths. Berengut et al. (Phys. Rev. Lett. 2013, 111, 010801) demonstrated the validity of such an analysis using high-resolution Space Telescope Imaging Spectrograph (STIS) spectra of G191-B2B. We have made three important improvements by: (a) using three new independent sets of laboratory wavelengths; (b) analysing a sample of objects; and (c) improving the methodology by incorporating robust techniques from previous studies towards quasars (the Many Multiplet method). A successful detection would be the first direct measurement of a gravitational field effect on a bare constant of nature. Here we describe our approach and present preliminary results from nine objects using both FeV and NiV.
    • PROBING THE INTERSTELLAR MEDIUM AND STAR FORMATION OF THE MOST LUMINOUS QUASAR AT z = 6.3

      Wang, Ran; Wu, Xue-Bing; Neri, Roberto; Fan, Xiaohui; Walter, Fabian; Carilli, Chris L.; Momjian, Emmanuel; Bertoldi, Frank; Strauss, Michael A.; Li, Qiong; et al. (IOP PUBLISHING LTD, 2016-10-10)
      We report new IRAM/PdBI, JCMT/SCUBA-2, and VLA observations of the ultraluminous quasar SDSS J010013.02+280225.8 (hereafter, J0100+2802) at z =. 6.3, which hosts the most massive supermassive black hole (SMBH), 1.24 x 10(10) M circle dot, that is known at z > 6. We detect the [C II] 158 mu m fine structure line and molecular CO(6-5) line and continuum emission at 353, 260, and 3 GHz from this quasar. The CO(2-1) line and the underlying continuum at 32 GHz are also marginally detected. The [C II] and CO detections suggest active star formation and highly excited molecular gas in the quasar host galaxy. The redshift determined with the [C II] and CO lines shows a velocity offset of similar to 1000 km s(-1) from that measured with the quasar Mg II line. The CO (2-1) line luminosity provides a direct constraint on the molecular gas mass, which is about (1.0 +/- 0.3) x 10(10) M circle dot We estimate the FIR luminosity to be (3.5 +/- 0.7) x 10(12) L circle dot, and the UV-to-FIR spectral energy distribution of J0100 +2802 is consistent with the templates of the local optically luminous quasars. The derived [C II]-to-FIR luminosity ratio of J0100+2802 is 0.0010 +/- 0.0002, which is slightly higher than the values of the most FIR luminous quasars at z similar to 6. We investigate the constraint on the host galaxy dynamical mass of J0100 vertical bar 2802 based on the [C II] line spectrum. It is likely that this ultraluminous quasar lies above the local SMBH-galaxy mass relationship, unless we are viewing the system at a small inclination angle.
    • Probing the Metal Enrichment of the Intergalactic Medium at z = 5–6 Using the Hubble Space Telescope

      Cai, Zheng; Fan, Xiaohui; Davé, Romeel; Finlator, Kristian; Oppenheimer, Ben; Univ Arizona, Steward Observ (IOP PUBLISHING LTD, 2017-10-26)
      We test the galactic outflow model by probing associated galaxies of four strong intergalactic C IV absorbers at z = 5-6 using the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) ramp narrowband filters. The four strong C IV absorbers reside at z = 5.74, 5.52, 4.95, and 4.87, with column densities ranging from N-C IV = 10(13.8) to 10(14.8) cm(-2). At z = 5.74, we detect an i-dropout Ly alpha emitter (LAE) candidate with a projected impact parameter of 42 physical kpc from the C IV absorber. This LAE candidate has a Ly alpha-based star formation rate (SFRLy alpha) of 2 M-circle dot yr(-1) and a UV-based SFR of 4 M-circle dot yr(-1). Although we cannot completely rule out that this i-dropout emitter may be an [O II] interloper, its measured properties are consistent with the C IV powered galaxy at z = 5.74. For C IV absorbers at z = 4.95 and z = 4.87, although we detect two LAE candidates with impact parameters of 160 and 200 kpc, such distances are larger than that predicted from the simulations. Therefore, we treat them as nondetections. For the system at z = 5.52, we do not detect LAE candidates, placing a 3 sigma upper limit of SFRLy alpha approximate to 1.5 M-circle dot yr(-1). In summary, in these four cases, we only detect one plausible C IV source at z = 5.74. Combining the modest SFR of the one detection and the three nondetections, our HST observations strongly support that smaller galaxies (SFRLy alpha less than or similar to 2 M-circle dot yr(-1)) are main sources of intergalactic C IV absorbers, and such small galaxies play a major role in the metal enrichment of the intergalactic medium at z greater than or similar to 5.
    • Probing the structure of nanodiscs using surface-induced dissociation mass spectrometry

      Harvey, Sophie R; VanAernum, Zachary L; Kostelic, Marius M; Marty, Michael T; Wysocki, Vicki H; Department of Chemistry and Biochemistry and Bio5 Institute, University of Arizona (Royal Society of Chemistry, 2020-12-08)
      In the study of membrane proteins and antimicrobial peptides, nanodiscs have emerged as a valuable membrane mimetic to solubilze these molecules in a lipid bilayer. We present the structural characterization of nanodiscs using native mass spectrometry and surface-induced dissociation, which are powerful tools in structural biology. This journal is © The Royal Society of Chemistry.
    • PROBING X-RAY ABSORPTION AND OPTICAL EXTINCTION IN THE INTERSTELLAR MEDIUM USING CHANDRA OBSERVATIONS OF SUPERNOVA REMNANTS

      Foight, Dillon R.; Güver, Tolga; Özel, Feryal; Slane, Patrick O.; Univ Arizona, Dept Astron (IOP PUBLISHING LTD, 2016-07-22)
      We present a comprehensive study of interstellar X-ray extinction using the extensive Chandra supernova remnant (SNR) archive and use our results to refine the empirical relation between the hydrogen column density and optical extinction. In our analysis, we make use of the large, uniform data sample to assess various systematic uncertainties in the measurement of the interstellar X-ray absorption. Specifically, we address systematic uncertainties that originate from (i) the emission models used to fit SNR spectra; (ii) the spatial variations within individual remnants; (iii) the physical conditions of the remnant such as composition, temperature, and non-equilibrium regions; and (iv) the model used for the absorption of X-rays in the interstellar medium. Using a Bayesian framework to quantify these systematic uncertainties, and combining the resulting hydrogen column density measurements with the measurements of optical extinction toward the same remnants, we find the empirical relation N-H = (2.87 +/- 0.12) x 10(21) A(V) cm(-2), which is significantly higher than the previous measurements.
    • ProcData: An R Package for Process Data Analysis

      Tang, Xueying; Zhang, Susu; Wang, Zhi; Liu, Jingchen; Ying, Zhiliang; University of Arizona (Springer, 2021-08-11)
      Process data refer to data recorded in log files of computer-based items. These data, represented as timestamped action sequences, keep track of respondents’ response problem-solving behaviors. Process data analysis aims at enhancing educational assessment accuracy and serving other assessment purposes by utilizing the rich information contained in response processes. The R package ProcData presented in this article is designed to provide tools for inspecting, processing, and analyzing process data. We define an S3 class ‘proc’ for organizing process data and extend generic methods summary and print for ‘proc’. Feature extraction methods for process data are implemented in the package for compressing information in the irregular response processes into regular numeric vectors. ProcData also provides functions for making predictions from neural-network-based sequence models. In addition, a real dataset of response processes from the climate control item in the 2012 Programme for International Student Assessment is included in the package. © 2021, The Psychometric Society.
    • Process modeling for economic optimization of a solar driven sweeping gas membrane distillation desalination system

      Moore, Sarah E.; Mirchandani, Sera D.; Karanikola, Vasiliki; Nenoff, Tina M.; Arnold, Robert G.; Eduardo Sáez, A.; Univ Arizona, Dept Environm Chem & Engn (ELSEVIER SCIENCE BV, 2018-07)
      Water scarcity is especially impactful in remote and impoverished communities without access to centralized water treatment plants. In areas with access to a saline water source, point-of-use desalination by solar-driven membrane distillation (MD) is a possible method for mitigating water scarcity. To evaluate the applicability of MD, a comprehensive process model was developed and used to design an economically optimal system. Thermal energy for distillation was provided by solar thermal collectors, and electricity was provided using photovoltaic collectors. Distillation was performed using sweeping-gas membrane distillation. The cost of water in the optimized system was approximately $85/m(3). Membrane modules and solar thermal collectors made up the largest portion of the cost. Neither thermal nor electrical energy storage was economical within current technologies. The model developed provides a template to optimize MD membrane characteristics specialized for point-of-use applications.
    • The process of genome shrinkage in the obligate symbiont Buchnera aphidicola

      Moran, Nancy; Mira, Alex; Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA (BioMed Central, 2001)
      BACKGROUND:Very small genomes have evolved repeatedly in eubacterial lineages that have adopted obligate associations with eukaryotic hosts. Complete genome sequences have revealed that small genomes retain very different gene sets, raising the question of how final genome content is determined. To examine the process of genome reduction, the tiny genome of the endosymbiont Buchnera aphidicola was compared to the larger ancestral genome, reconstructed on the basis of the phylogenetic distribution of gene orthologs among fully sequenced relatives of Escherichia coli and Buchnera.RESULTS:The reconstructed ancestral genome contained 2,425 open reading frames (ORFs). The Buchnera genome, containing 564 ORFs, consists of 153 fragments of 1-34 genes that are syntenic with reconstructed ancestral regions. On the basis of this reconstruction, 503 genes were eliminated within syntenic fragments, and 1,403 genes were lost from the gaps between syntenic fragments, probably in connection with genome rearrangements. Lost regions are sometimes large, and often span functionally unrelated genes. In addition, individual genes and regulatory regions have been lost or eroded. For the categories of DNA repair genes and rRNA genes, most lost loci fall in regions between syntenic fragments. This history of gene loss is reflected in the sequences of intergenic spacers at positions where genes were once present.CONCLUSIONS:The most plausible interpretation of this reconstruction is that Buchnera lost many genes through the fixation of large deletions soon after the acquisition of an obligate endosymbiotic lifestyle. An implication is that final genome composition may be partly the chance outcome of initial deletions and that neighboring genes influence the likelihood of loss of particular genes and pathways.
    • Process optimization for efficient convergence in large optics fabrication

      Oh, Chang Jin; Martin, Hubert M.; Lowman, Andrew E.; Smith, Greg A.; Univ Arizona, Coll Opt Sci; Univ Arizona, Steward Observ (SPIE-INT SOC OPTICAL ENGINEERING, 2018)
      Large optic fabrication is a delicate and time consuming process. Obtaining a large prime optic is often in the critical path of a project and poses a serious risk to both the schedule and budget. The Optical Engineering and Fabrication Facility (OEFF) at the College of Optical Sciences, the University of Arizona, has developed a new way of optimizing its large optic fabrication process for maximum efficiency in convergence. The new process optimization takes the amount of stock material removal, tool characteristics, metrology uncertainty, optic prescription, optic material properties, and resource availability as input parameters and provides an optimized process along with an achievable convergence. This paper presents technical details of the new process optimization and demonstrates performance on 6.5m mirror fabrication at the University of Arizona. Two case studies for an 8.4m GMT off-axis primary mirror segment and a 3.1m TMT convex secondary mirror fabrication are also presented.
    • Processes of Native Nationhood: The Indigenous Politics of Self-Government

      Cornell, Stephen; Univ Arizona (UNIV WESTERN ONTARIO, 2015-09)
      Over the last three decades, Indigenous peoples in the CANZUS countries (Canada, Australia, New Zealand, and the United States) have been reclaiming self-government as an Indigenous right and practice. In the process, they have been asserting various forms of Indigenous nationhood. This article argues that this development involves a common set of activities on the part of Indigenous peoples: (1) identifying as a nation or a people (determining who the appropriate collective "self " is in self-determination and self-government); (2) organizing as a political body (not just as a corporate holder of assets); and (3) acting on behalf of Indigenous goals (asserting and exercising practical decision-making power and responsibility, even in cases where central governments deny recognition). The article compares these activities in the four countries and argues that, while contexts and circumstances differ, the Indigenous politics of self-government show striking commonalities across the four. Among those commonalities: it is a positional as opposed to a distributional politics; while not ignoring individual welfare, it measures success in terms of collective power; and it focuses less on what central governments are willing to do in the way of recognition and rights than on what Indigenous nations or communities can do for themselves.
    • Processes of Paleoindian site and desert pavement formation in the Atacama Desert, Chile

      Ugalde, Paula C.; Quade, Jay; Santoro, Calogero M.; Holliday, Vance T.; Univ Arizona, Sch Anthropol; Univ Arizona, Dept Geosci (CAMBRIDGE UNIV PRESS, 2020-06-19)
      A distinct feature of many of the earliest archaeological sites (13,000-11,200 cal yr BP) at the core of the Atacama Desert is that they lie at or just below the surface, often encased in desert pavements. In this study, we compare these sites and undisturbed desert pavements to understand archaeological site formation and pavement development and recovery. Our results indicate these pavements and their soils are poorly developed regardless of their age. We propose that this is because of sustained lack of rain and extreme physical breakdown of clasts by salt expansion. Thus, the core of the Atacama provides an example of the lower limits of rainfall (<50 mm/yr) needed to form desert pavements. At site Quebrada Mani 12 (QM12), humans destroyed the pavement. After abandonment, human-made depressions were filled with eolian sands, incorporating artifacts in shallow deposits. Small and medium-sized artifacts preferentially migrated upwards, perhaps due to earthquakes and the action of salts. These artifacts, which now form palimpsests at the surface, helped - along with older clasts - to restore surface clast cover. Larger archaeological features remained undisturbed on top of a deeper Byzm horizon. The vesicular A horizons (Av horizons) have not regenerated on the archaeological sites due to extreme scarcity of rainfall during the Holocene.
    • The processivity factor Pol32 mediates nuclear localization of DNA polymerase delta and prevents chromosomal fragile site formation in Drosophila development

      Ji, Jingyun; Tang, Xiaona; Hu, Wen; Maggert, Keith A; Rong, Yikang S; Univ Arizona, Dept Cellular & Mol Med (PUBLIC LIBRARY SCIENCE, 2019-05)
      The Pol32 protein is one of the universal subunits of DNA polymerase (Pol ), which is responsible for genome replication in eukaryotic cells. Although the role of Pol32 in DNA repair has been well-characterized, its exact function in genome replication remains obscure as studies in single cell systems have not established an essential role for Pol32 in the process. Here we characterize Pol32 in the context of Drosophila melanogaster development. In the rapidly dividing embryonic cells, loss of Pol32 halts genome replication as it specifically disrupts Pol localization to the nucleus. This function of Pol32 in facilitating the nuclear import of Pol would be similar to that of accessory subunits of DNA polymerases from mammalian Herpes viruses. In post-embryonic cells, loss of Pol32 reveals mitotic fragile sites in the Drosophila genome, a defect more consistent with Pol32's role as a polymerase processivity factor. Interestingly, these fragile sites do not favor repetitive sequences in heterochromatin, with the rDNA locus being a striking exception. Our study uncovers a possibly universal function for DNA polymerase ancillary factors and establishes a powerful system for the study of chromosomal fragile sites in a non-mammalian organism. Author summary Cancer etiological studies suggest that the majority of pathological mutations occurred under near normal DNA replication conditions, emphasizing the importance of understanding replication regulation under non-lethal conditions. To gain such a better understanding, we investigated the function of Pol32, a conserved ancillary subunit of the essential DNA polymerase Delta complex, through the development of the fruit fly Drosophila. We uncovered a previously unappreciated function of Pol32 in regulating the nuclear import of the polymerase complex, and this function is developmentally regulated. By utilizing mutations in pol32 and other replication factors, we have started to define basic features of Chromosome Fragile Sites (CFS) in Drosophila somatic cells. CFS is a major source of genome instability associated with replication stresses, and has been an important topic of cancer biology. We discovered that CFS formation does not favor genomic regions with repetitive sequences except the highly transcribed locus encoding ribosomal RNA. Our work lays the groundwork for future studies using Drosophila as an alternative system to uncover the most fundamental features of CFS.
    • Producing a BOSS CMASS sample with DES imaging

      Lee, S; Huff, E M; Ross, A J; Choi, A; Hirata, C; Honscheid, K; MacCrann, N; Troxel, M A; Davis, C; Eifler, T F; et al. (OXFORD UNIV PRESS, 2019-09-02)
      We present a sample of galaxies with theDark Energy Survey (DES) photometry that replicates the properties of the BOSS CMASS sample. The CMASS galaxy sample has been well characterized by the Sloan Digital Sky Survey (SDSS) collaboration and was used to obtain the most powerful redshift-space galaxy clustering measurements to date. A joint analysis of redshift-space distortions (such as those probed by CMASS from SDSS) and a galaxy-galaxy lensing measurement for an equivalent sample from DES can provide powerful cosmological constraints. Unfortunately, the DES and SDSS-BOSS footprints have only minimal overlap, primarily on the celestial equator near the SDSS Stripe 82 region. Using this overlap, we build a robust Bayesian model to select CMASS-like galaxies in the remainder of the DES footprint. The newly defined DES-CMASS (DMASS) sample consists of 117 293 effective galaxies covering 1244 deg(2). Through various validation tests, we show that the DMASS sample selected by this model matches well with the BOSS CMASS sample, specifically in the South Galactic cap (SGC) region that includes Stripe 82. Combining measurements of the angular correlation function and the clustering-z distribution of DMASS, we constrain the difference in mean galaxy bias and mean redshift between the BOSS CMASS and DMASS samples to be Delta b = 0.010(-0.052)(+0.045) and Delta z = (3.46(-5.55)(+5.48)) x 10(-3) for the SGC portion of CMASS, and Delta b = 0.044(-0.043)(+0.044) and Delta z = (3.51(-5.91)(+4.93)) x 10(-3) for the full CMASS sample. These values indicate that the mean bias of galaxies and mean redshift in the DMASS sample are consistent with both CMASS samples within 1 sigma.
    • Production and perception of the English /æ/–/ɑ/ contrast in switched-dominance speakers

      Casillas, Joseph V; Simonet, Miquel; Univ Arizona (SAGE PUBLICATIONS INC, 2016)
      This study investigates how fluent second-language (L2) learners of English produce and perceive the /æ/–/ɑ/ vowel contrast of Southwestern American English. Two learner groups are examined: (1) early, proficient English speakers who were raised by Spanish-speaking families but who became dominant in English during childhood and, as adults, lack communicative abilities in Spanish, and (2) Spanish-speaking late learners of English who continue to be dominant in Spanish. The participants provided data in three tasks: one production and two perceptual. The study finds that both learner groups differ from native controls in their production and perception of the /æ/–/ɑ/ contrast. The findings shed light on our understanding of the relative effects of age (at onset of language exposure) and language dominance (at time of testing) by showing that sequential bilingualism impacts phonetic behavior even when speakers have become dominant in the target language.
    • A production-scale evaluation of nutritional monitoring and decision support software for free-ranging cattle in an arid environment

      Brooks (Turner), Rachel J.; Tolleson, Douglas R.; Ruyle, George B.; Faulkner, Dan B.; University of Arizona, School of Natural Resources and the Environment; University of Arizona Agriculture Research Station (CSIRO Publishing, 2021)
      Range cattle in semi-arid regions are commonly limited by lack of nitrogen and other nutrients from grazing low-quality forage, with managers needing to monitor diet quality to address nutrient limitations. Near-infrared spectroscopy of faecal samples (FNIRS) is an accurate method used to determine diet quality in grazing animals. When combined with a nutritional balance software such as the Nutritional Balance Analyser (NUTBAL), FNIRS can monitor nutritional status and estimate weight change. We aimed to test the ability of NUTBAL to predict animal performance as represented by body condition score (BCS) in cattle grazing on a semi-desert rangeland. BCS and faecal samples were collected from a Red Angus herd (n = 82) at the Santa Rita Ranch (June 2016-July 2017). Standing biomass and botanical composition were measured before each grazing period, and relative utilisation was measured following each grazing period. During the midpoint of grazing in each pasture, 30 BCS and a faecal composite of 15 samples were collected. Faecal derived diet quality varied between a maximum of 10.75% crude protein (CP) and 61.25% digestible organic matter (DOM) in early August 2016, to a minimum value of 4.22% CP and 57.68% DOM in January 2017. Three NUTBAL evaluations were conducted to determine the likelihood of accurately predicting animal performance: one with typical user defined inputs; one with improved environment and herd descriptive inputs; and one with these improvements plus the use of metabolisable protein in the model. This third evaluation confirmed the ability of FNIRS:NUTBAL to predict future BCS within 0.5 BCS more than 75% of the time. With this information, cattle managers in semi-arid regions can better address animal performance needs and nutrient deficiencies.
    • Profiles of MBL Cloud and Drizzle Microphysical Properties Retrieved From Ground‐Based Observations and Validated by Aircraft In Situ Measurements Over the Azores

      Wu, Peng; Dong, Xiquan; Xi, Baike; Tian, Jingjing; Ward, Dale M.; Univ Arizona, Dept Hydrol & Atmospher Sci (AMER GEOPHYSICAL UNION, 2020-04-23)
      The profiles of marine boundary layer (MBL) cloud and drizzle microphysical properties are important for studying the cloud-to-rain conversion and growth processes in MBL clouds. However, it is challenging to simultaneously retrieve both cloud and drizzle microphysical properties within an MBL cloud layer using ground-based observations. In this study, methods were developed to first decompose drizzle and cloud reflectivity in MBL clouds from Atmospheric Radiation Measurement cloud radar reflectivity measurements and then simultaneously retrieve cloud and drizzle microphysical properties during the Aerosol and Cloud Experiments in the Eastern North Atlantic (ACE-ENA) campaign. These retrieved microphysical properties, such as cloud and drizzle particle size (r(c) and r(m,d)), their number concentration (N-c and N-d) and liquid water content (LWCc and LWCd), have been validated by aircraft in situ measurements during ACE-ENA (158 hr of aircraft data). The mean surface retrieved (in situ measured) r(c), N-c, and LWCc are 10.9 mu m (11.8 mu m), 70 cm(-3) (60 cm(-3)), and 0.21 g m(-3) (0.22 g m(-3)), respectively. For drizzle microphysical properties, the retrieved (in situ measured) r(d), N-d, and LWCd are 44.9 mu m (45.1 mu m), 0.07 cm(-3) (0.08 cm(-3)), and 0.052 g m(-3) (0.066 g m(-3)), respectively. Treating the aircraft in situ measurements as truth, the estimated median retrieval errors are 15% for r(c), 35% for N-c, 30% for LWCc and r(d), and 50% for N-d and LWCd. The findings from this study will provide insightful information for improving our understanding of warm rain processes, as well as for improving model simulations. More studies are required over other climatic regions.
    • Profiling caregivers: Hormonal variation underlying allomaternal care in wild red-bellied lemurs, Eulemur rubriventer

      Tecot, Stacey R.; Baden, Andrea L.; Univ Arizona, Sch Anthropol; Univ Arizona, Laboratory for the Evolutionary Endocrinology of Primates (Elsevier, 2018-09-01)
    • Profiling caregivers: Hormonal variation underlying allomaternal care in wild red-bellied lemurs, Eulemur rubriventer

      Tecot, Stacey R.; Baden, Andrea L.; Univ Arizona, Sch Anthropol; Univ Arizona, Lab Evolutionary Endocrinol Primates (PERGAMON-ELSEVIER SCIENCE LTD, 2018-09-01)
      Neuroendocrine evidence suggests that paternal care is mediated by hormonal mechanisms, where hormonal changes in expectant and new fathers facilitate infant care. In species with obligate and extensive paternal care such as humans, androgen levels decline once males are paired and have offspring, and in direct response to offspring care. Facultative infant care is widespread in the Order Primates, but the underlying hormonal mechanisms are largely unknown. We found that wild, red-bellied lemurs living in family groups (two adults and their presumed offspring) varied in the amount of care they provided infants. The more fathers invested in helping infants (measured as a composite of carrying, holding, huddling, grooming, and playing), and specifically the more they huddled and groomed with infants, the higher their fecal androgen (fA) levels, contrary to expectations. Carrying was negatively related to fA levels. Helping by subadults and juveniles was not related to their own fA levels. Elevated fA levels during infant dependence have been observed in other vertebrate species, and are thought to reflect reinvestment in mating rather than investment in dependent offspring. However, red-bellied lemurs do not mate until after infants are weaned, and they have long-term pair-bonds, suggesting that elevated fA levels play a role in offspring care. These results support a growing body of research suggesting that elevated androgen levels do not inhibit protective infant care.
    • Progenitor, precursor, and evolution of the dusty remnant of the stellar merger M31-LRN-2015

      Blagorodnova, N; Karambelkar, V; Adams, S M; Kasliwal, M M; Kochanek, C S; Dong, S; Campbell, H; Hodgkin, S; Jencson, J E; Johansson, J; et al. (OXFORD UNIV PRESS, 2020-06-30)
      M31-LRN-2015 is a likely stellar merger discovered in the Andromeda Galaxy in 2015. We present new optical to mid-infrared photometry and optical spectroscopy for this event. Archival data show that the source started to brighten similar to 2 yr before the nova event. During this precursor phase, the source brightened by similar to 3 mag. The light curve at 6 and 1.5 months before the main outburst may show periodicity, with periods of 16 +/- 0.3 and 28.1 +/- 1.4 d, respectively. This complex emission may be explained by runaway mass-loss from the system after the binary undergoes Roche lobe overflow, leading the system to coalesce in tens of orbital periods. While the progenitor spectral energy distribution shows no evidence of pre-existing warm dust in the system, the remnant forms an optically thick dust shell at approximately four months after the outburst peak. The optical depth of the shell increases dramatically after 1.5 yr, suggesting the existence of shocks that enhance the dust formation process. We propose that the merger remnant is likely an inflated giant obscured by a cooling shell of gas with mass similar to 0.2 M-circle dot ejected at the onset of the common envelope phase.