Signatures of minor mergers in the Milky Way disc – I. The SEGUE stellar sample

Gó,mez, Facundo A.,Minchev, Ivan,O’Shea, Brian W.,Lee, Young Sun,Beers, Timothy C.,An, Deokkeun,Bullock, James S.,Purcell, Chris W.,Villalobos, Á,lvaro Blackwell Publishing Ltd 2012 Monthly notices of the Royal Astronomical Society Vol.423 No.4

<P><B>ABSTRACT</B></P><P>It is now known that minor mergers are capable of creating structure in the phase‐space distribution of their host galaxy’s disc. In order to search for such imprints in the Milky Way, we analyse the Sloan Extension for Galactic Understanding and Exploration (SEGUE) F/G dwarf and the Schuster et al. stellar samples. We find similar features in these two completely independent stellar samples, consistent with the predictions of a Milky Way minor‐merger event. We next apply the same analyses to high‐resolution, idealized <I>N</I>‐body simulations of the interaction between the Sagittarius dwarf galaxy and the Milky Way. The energy distributions of stellar particle samples in small spatial regions in the host disc reveal strong variations of structure with position. We find good matches to the observations for models with a mass of Sagittarius’ dark matter halo progenitor <IMG src='/wiley-blackwell_img/lap.gif' alt ='less-than or approximately equal-to'/>10<SUP>11</SUP> M<SUB>⊙</SUB>. Thus, we show that this kind of analysis could be used to provide unprecedentedly tight constraints on Sagittarius’ orbital parameters, as well as place a lower limit on its mass.</P>

Quantitative aspects of the identification of Fe(<small>II</small>) moieties in ZSM-5 zeolites with various pore hierarchies

Gó,ra-Marek, Kinga,Brylewska, Kamila,Tarach, Karolina A.,Choi, Minkee The Royal Society of Chemistry 2015 Dalton Transactions Vol.44 No.17

<P>This work was attempted in order to provide a new and well-established approach for the quantification of Fe<SUP>2+</SUP> sites in zeolites. The experimental procedure was based on carbon monoxide and nitrogen monoxide sorption in Fe-exchanged ZSM-5 zeolites with different pore hierarchies, which was followed by IR spectroscopy. The values of the absorption coefficients of the respective monocarbonyl Fe<SUP>2+</SUP>(CO) and mononitrosyl Fe<SUP>2+</SUP>(NO) IR bands were obtained. In turn, the concentrations of Fe(<SMALL>II</SMALL>) moieties of various kinds were calculated and discussed with regard to the composition (Si/Al and Fe/Al ratios) of the zeolites studied.</P> <P>Graphic Abstract</P><P>This work was attempted in order to provide a new and well-established approach for the quantification of Fe<SUP>2+</SUP> sites in zeolites. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c5dt00424a'> </P>

THE UNUSUAL VERTICAL MASS DISTRIBUTION OF NGC 4013 SEEN THROUGH THE <i>SPITZER</i> SURVEY OF STELLAR STRUCTURE IN GALAXIES (S ⁴ G)

Comer&oacute,n, Sé,bastien,Elmegreen, Bruce G.,Knapen, Johan H.,Sheth, Kartik,Hinz, Joannah L.,Regan, Michael W.,Gil de Paz, Armando,Muñ,oz-Mateos, Juan-Carlos,Mené,ndez-Delmestre, K IOP Publishing 2011 ASTROPHYSICAL JOURNAL LETTERS - Vol.738 No.2

<P>NGC 4013 is a nearby Sb edge-on galaxy known for its 'prodigious' Hi warp and its 'giant' tidal stream. Previous work on this unusual object shows that it cannot be fitted satisfactorily by a canonical thin+thick disk structure. We have produced a new decomposition of NGC 4013, considering three stellar flattened components (thin+thick disk plus an extra and more extended component) and one gaseous disk. All four components are considered to be gravitationally coupled and isothermal. To do so, we have used the 3.6 mu m images from the Spitzer Survey of Stellar Structure in Galaxies. We find evidence for NGC 4013 indeed having a thin and a thick disk and an extra flattened component. This smooth and extended component (scale height z(EC) similar to 3 kpc) could be interpreted as a thick disk or as a squashed ellipsoidal halo and contains similar to 20% of the total mass of all three stellar components. We argue it is unlikely to be related to the ongoing merger or due to the off-plane stars from a warp in the other two disk components. Instead, we favor a scenario in which the thick disk and the extended component were formed in a two-stage process, in which an initially thick disk has been dynamically heated by a merger soon enough in the galaxy history to have a new thick disk formed within it.</P>

Assessment via the modified gompertz-model reveals new insights concerning the effects of ionic liquids on biohydrogen production

Nemest&oacute,thy, Ná,ndor,Bakonyi, Pé,ter,R&oacute,zsenberszki, Tamá,s,Kumar, Gopalakrishnan,Ko&oacute,k, Lá,szl&oacute,Kelemen, Gá,bor,Kim, Sang-Hyoun,Bé,lafi-Bak Elsevier 2018 International journal of hydrogen energy Vol.43 No.41

<P><B>Abstract</B></P> <P>Lignocellulosic biofuel, in particular hydrogen gas production is governed by successful feedstock pretreatment, hydrolysis and fermentation. In these days, remarkable attention is paid to the use of ionic liquids to make the fermentable regions of lignocellulose biomass more accessible to the biocatalysts. Although these compounds have great potential for this purpose, their presence during the consecutive fermentation stage may pose a threat on process stability due to certain toxic effects. This, however, has not been specifically elaborated for dark fermentative biohydrogen generation. Hence, in this work, two common imidazolium-type ionic liquids (1-butyl-3-methylimidazolium acetate, ([bmim][Ac]) and 1-butyl-3-methylimidazolium chloride, ([bmim][Cl])) were employed in mixed culture biohydrogen fermentation to investigate the possible impacts related to their presence and concentrations. The batch assays were evaluated comparatively via the modified Gompertz-model based on the important parameters characterizing the process, namely the biohydrogen production potential, maximum biohydrogen production rate and lag-phase time.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The impact of imidazolium-type ionic liquids on biohydrogen formation was tested. </LI> <LI> The batch biohydrogen production process was evaluated kinetically. </LI> <LI> Both [bmim][Ac] and [bmim][Cl] affected the biohydrogen formation performance. </LI> <LI> The anion part of ionic liquids ([Ac]<SUP>-</SUP> vs. [Cl]<SUP>-</SUP>) demonstrated notable effect. </LI> </UL> </P>

BREAKS IN THIN AND THICK DISKS OF EDGE-ON GALAXIES IMAGED IN THE<i>SPITZER</i>SURVEY OF STELLAR STRUCTURE IN GALAXIES (S⁴G)

Comer&oacute,n, Sé,bastien,Elmegreen, Bruce G.,Salo, Heikki,Laurikainen, Eija,Athanassoula, E.,Bosma, Albert,Knapen, Johan H.,Gadotti, Dimitri A.,Sheth, Kartik,Hinz, Joannah L.,Regan, Michael W. IOP Publishing 2012 The Astrophysical journal Vol.759 No.2

<P>Breaks in the radial luminosity profiles of galaxies have until now been mostly studied averaged over disks. Here, we study separately breaks in thin and thick disks in 70 edge-on galaxies using imaging from the Spitzer Survey of Stellar Structure in Galaxies. We built luminosity profiles of the thin and thick disks parallel to midplanes and we found that thin disks often truncate (77%). Thick disks truncate less often (31%), but when they do, their break radius is comparable with that in the thin disk. This suggests either two different truncation mechanisms-one of dynamical origin affecting both disks simultaneously and another one only affecting the thin disk-or a single mechanism that creates a truncation in one disk or in both depending on some galaxy property. Thin disks apparently antitruncate in around 40% of galaxies. However, in many cases, these antitruncations are an artifact caused by the superposition of a thin disk and a thick disk, with the latter having a longer scale length. We estimate the real thin disk antitruncation fraction to be less than 15%. We found that the ratio of the thick and thin stellar disk mass is roughly constant (0.2 < M-T/M-t < 0.7) for circular velocities v(c) > 120 km s(-1), but becomes much larger at smaller velocities. We hypothesize that this is due to a combination of a high efficiency of supernova feedback and a slower dynamical evolution in lower-mass galaxies causing stellar thin disks to be younger and less massive than in higher-mass galaxies.</P>

Evolution of asexual and sexual reproduction in the aspergilli

Ojeda-L&oacute,pez, M.,Chen, W.,Eagle, C.E.,Gutié,rrez, G.,Jia, W.L.,Swilaiman, S.S.,Huang, Z.,Park, H.-S.,Yu, J.-H.,Cá,novas, D.,Dyer, P.S. CBS Fungal Biodiversity Centre 2018 Studies in mycology Vol.91 No.-

<P><I>Aspergillus nidulans</I> has long-been used as a model organism to gain insights into the genetic basis of asexual and sexual developmental processes both in other members of the genus <I>Aspergillus</I>, and filamentous fungi in general. Paradigms have been established concerning the regulatory mechanisms of conidial development. However, recent studies have shown considerable genome divergence in the fungal kingdom, questioning the general applicability of findings from <I>Aspergillus</I>, and certain longstanding evolutionary theories have been questioned. The phylogenetic distribution of key regulatory elements of asexual reproduction in <I>A. nidulans</I> was investigated in a broad taxonomic range of fungi. This revealed that some proteins were well conserved in the <I>Pezizomycotina</I> (<I>e.g.</I> AbaA, FlbA, FluG, NsdD, MedA, and some velvet proteins), suggesting similar developmental roles. However, other elements (<I>e.g.</I> BrlA) had a more restricted distribution solely in the <I>Eurotiomycetes</I>, and it appears that the genetic control of sporulation seems to be more complex in the aspergilli than in some other taxonomic groups of the <I>Pezizomycotina</I>. The evolution of the velvet protein family is discussed based on the history of expansion and contraction events in the early divergent fungi. Heterologous expression of the <I>A. nidulans abaA</I> gene in <I>Monascus ruber</I> failed to induce development of complete conidiophores as seen in the aspergilli, but did result in increased conidial production. The absence of many components of the asexual developmental pathway from members of the <I>Saccharomycotina</I> supports the hypothesis that differences in the complexity of their spore formation is due in part to the increased diversity of the sporulation machinery evident in the <I>Pezizomycotina</I>. Investigations were also made into the evolution of sex and sexuality in the aspergilli. <I>MAT</I> loci were identified from the heterothallic <I>Aspergillus</I> (<I>Emericella</I>) <I>heterothallicus</I> and <I>Aspergillus</I> (<I>Neosartorya</I>) <I>fennelliae</I> and the homothallic <I>Aspergillus pseudoglaucus</I> (=<I>Eurotium repens</I>). A consistent architecture of the <I>MAT</I> locus was seen in these and other heterothallic aspergilli whereas much variation was seen in the arrangement of <I>MAT</I> loci in homothallic aspergilli. This suggested that it is most likely that the common ancestor of the aspergilli exhibited a heterothallic breeding system. Finally, the supposed prevalence of asexuality in the aspergilli was examined. Investigations were made using <I>A. clavatus</I> as a representative ‘asexual’ species. It was possible to induce a sexual cycle in <I>A. clavatus</I> given the correct <I>MAT1-1</I> and <I>MAT1-2</I> partners and environmental conditions, with recombination confirmed utilising molecular markers. This indicated that sexual reproduction might be possible in many supposedly asexual aspergilli and beyond, providing general insights into the nature of asexuality in fungi.</P>

Worldwide trends in body-mass index, underweight, overweight, and obesity from 1975 to 2016: a pooled analysis of 2416 population-based measurement studies in 128·9 million children, adolescents, and adults

Abarca-Gó,mez, Leandra,Abdeen, Ziad A,Hamid, Zargar Abdul,Abu-Rmeileh, Niveen M,Acosta-Cazares, Benjamin,Acuin, Cecilia,Adams, Robert J,Aekplakorn, Wichai,Afsana, Kaosar,Aguilar-Salinas, Carlos Elsevier 2017 The Lancet Vol.390 No.10113

<P><B>Summary</B></P> <P><B>Background</B></P> <P>Underweight, overweight, and obesity in childhood and adolescence are associated with adverse health consequences throughout the life-course. Our aim was to estimate worldwide trends in mean body-mass index (BMI) and a comprehensive set of BMI categories that cover underweight to obesity in children and adolescents, and to compare trends with those of adults.</P> <P><B>Methods</B></P> <P>We pooled 2416 population-based studies with measurements of height and weight on 128·9 million participants aged 5 years and older, including 31·5 million aged 5–19 years. We used a Bayesian hierarchical model to estimate trends from 1975 to 2016 in 200 countries for mean BMI and for prevalence of BMI in the following categories for children and adolescents aged 5–19 years: more than 2 SD below the median of the WHO growth reference for children and adolescents (referred to as moderate and severe underweight hereafter), 2 SD to more than 1 SD below the median (mild underweight), 1 SD below the median to 1 SD above the median (healthy weight), more than 1 SD to 2 SD above the median (overweight but not obese), and more than 2 SD above the median (obesity).</P> <P><B>Findings</B></P> <P>Regional change in age-standardised mean BMI in girls from 1975 to 2016 ranged from virtually no change (−0·01 kg/m<SUP>2</SUP> per decade; 95% credible interval −0·42 to 0·39, posterior probability [PP] of the observed decrease being a true decrease=0·5098) in eastern Europe to an increase of 1·00 kg/m<SUP>2</SUP> per decade (0·69–1·35, PP>0·9999) in central Latin America and an increase of 0·95 kg/m<SUP>2</SUP> per decade (0·64–1·25, PP>0·9999) in Polynesia and Micronesia. The range for boys was from a non-significant increase of 0·09 kg/m<SUP>2</SUP> per decade (−0·33 to 0·49, PP=0·6926) in eastern Europe to an increase of 0·77 kg/m<SUP>2</SUP> per decade (0·50–1·06, PP>0·9999) in Polynesia and Micronesia. Trends in mean BMI have recently flattened in northwestern Europe and the high-income English-speaking and Asia-Pacific regions for both sexes, southwestern Europe for boys, and central and Andean Latin America for girls. By contrast, the rise in BMI has accelerated in east and south Asia for both sexes, and southeast Asia for boys. Global age-standardised prevalence of obesity increased from 0·7% (0·4–1·2) in 1975 to 5·6% (4·8–6·5) in 2016 in girls, and from 0·9% (0·5–1·3) in 1975 to 7·8% (6·7–9·1) in 2016 in boys; the prevalence of moderate and severe underweight decreased from 9·2% (6·0–12·9) in 1975 to 8·4% (6·8–10·1) in 2016 in girls and from 14·8% (10·4–19·5) in 1975 to 12·4% (10·3–14·5) in 2016 in boys. Prevalence of moderate and severe underweight was highest in India, at 22·7% (16·7–29·6) among girls and 30·7% (23·5–38·0) among boys. Prevalence of obesity was more than 30% in girls in Nauru, the Cook Islands, and Palau; and boys in the Cook Islands, Nauru, Palau, Niue, and American Samoa in 2016. Prevalence of obesity was about 20% or more in several countries in Polynesia and Micronesia, the Middle East and north Africa, the Caribbean, and the USA. In 2016, 75 (44–117) million girls and 117 (70–178) million boys worldwide were moderately or severely underweight. In the same year, 50 (24–89) million girls and 74 (39–125) million boys worldwide were obese.</P> <P><B>Interpretation</B></P> <P>The rising trends in children's and adolescents' BMI have plateaued in many high-income countries, albeit at high lev

THICK DISKS OF EDGE-ON GALAXIES SEEN THROUGH THE<i>SPITZER</i>SURVEY OF STELLAR STRUCTURE IN GALAXIES (S⁴G): LAIR OF MISSING BARYONS?

Comer&oacute,n, Sé,bastien,Elmegreen, Bruce G.,Knapen, Johan H.,Salo, Heikki,Laurikainen, Eija,Laine, Jarkko,Athanassoula, E.,Bosma, Albert,Sheth, Kartik,Regan, Michael W.,Hinz, Joannah L.,de Pa IOP Publishing 2011 The Astrophysical journal Vol.741 No.1

<P>Most, if not all, disk galaxies have a thin (classical) disk and a thick disk. In most models thick disks are thought to be a necessary consequence of the disk formation and/or evolution of the galaxy. We present the results of a study of the thick disk properties in a sample of carefully selected edge-on galaxies with types ranging from T = 3 to T = 8. We fitted one-dimensional luminosity profiles with physically motivated functions-the solutions of two stellar and one gaseous isothermal coupled disks in equilibrium-which are likely to yield more accurate results than other functions used in previous studies. The images used for the fits come from the Spitzer Survey of Stellar Structure in Galaxies (S(4)G). We found that thick disks are on average more massive than previously reported, mostly due to the selected fitting function. Typically, the thin and thick disks have similar masses. We also found that thick disks do not flare significantly within the observed range in galactocentric radii and that the ratio of thick-to-thin disk scale heights is higher for galaxies of earlier types. Our results tend to favor an in situ origin for most of the stars in the thick disk. In addition, the thick disk may contain a significant amount of stars coming from satellites accreted after the initial buildup of the galaxy and an extra fraction of stars coming from the secular heating of the thin disk by its own overdensities. Assigning thick disk light to the thin disk component may lead to an underestimate of the overall stellar mass in galaxies because of different mass-to-light ratios in the two disk components. On the basis of our new results, we estimate that disk stellar masses are between 10% and 50% higher than previously thought and we suggest that thick disks are a reservoir of 'local missing baryons.'</P>

Time and energy dependent dynamics of the STM tip — graphene system

Vancs&oacute,, P.,Má,rk, G. I.,Lambin, Ph.,Hwang, C.,Bir&oacute,, L. P. Springer-Verlag 2012 The European physical journal. B Vol.85 No.4

The SAURON project – XIX. Optical and near‐infrared scaling relations of nearby elliptical, lenticular and Sa galaxies

Falc&oacute,n‐,Barroso, J.,van de Ven, G.,Peletier, R. F.,Bureau, M.,Jeong, H.,Bacon, R.,Cappellari, M.,Davies, R. L.,de Zeeuw, P. T.,Emsellem, E.,Krajnović,, D.,Kuntschner, H.,McDermid, R. Blackwell Publishing Ltd 2011 MONTHLY NOTICES- ROYAL ASTRONOMICAL SOCIETY Vol.417 No.3

<P><B>ABSTRACT</B></P><P>We present ground‐based MDM Observatory <I>V</I>‐band and <I>Spitzer</I>/InfraRed Array Camera 3.6‐<IMG src='/wiley-blackwell_img/equation/MNR_19372_mu1.gif' alt ='inline image'/>m‐band photometric observations of the 72 representative galaxies of the SAURON survey. Galaxies in our sample probe the elliptical E, lenticular S0 and spiral Sa populations in the nearby Universe, both in field and cluster environments. We perform aperture photometry to derive homogeneous structural quantities. In combination with the SAURON stellar velocity dispersion measured within an effective radius (σ<SUB>e</SUB>), this allows us to explore the location of our galaxies in the colour–magnitude, colour–σ<SUB>e</SUB>, Kormendy, Faber–Jackson and Fundamental Plane scaling relations. We investigate the dependence of these relations on our recent kinematical classification of early‐type galaxies (i.e. slow/fast rotators) and the stellar populations. Slow rotator and fast rotator E/S0 galaxies do not populate distinct locations in the scaling relations, although slow rotators display a smaller intrinsic scatter. We find that Sa galaxies deviate from the colour–magnitude and colour–σ<SUB>e</SUB> relations due to the presence of dust, while the E/S0 galaxies define tight relations. Surprisingly, extremely young objects do not display the bluest (<I>V</I>−[3.6]) colours in our sample, as is usually the case in optical colours. This can be understood in the context of the large contribution of thermally pulsing asymptotic giant branch stars to the infrared, even for young populations, resulting in a very tight (<I>V</I>−[3.6])–σ<SUB>e</SUB> relation that in turn allows us to define a strong correlation between metallicity and σ<SUB>e</SUB>. Many Sa galaxies appear to follow the Fundamental Plane defined by E/S0 galaxies. Galaxies that appear offset from the relations correspond mostly to objects with extremely young populations, with signs of ongoing, extended star formation. We correct for this effect in the Fundamental Plane, by replacing luminosity with stellar mass using an estimate of the stellar mass‐to‐light ratio, so that all galaxies are part of a tight, single relation. The new estimated coefficients are consistent in both photometric bands and suggest that differences in stellar populations account for about half of the observed tilt with respect to the virial prediction. After these corrections, the slow rotator family shows almost no intrinsic scatter around the best‐fitting Fundamental Plane. The use of a velocity dispersion within a small aperture (e.g. <I>R</I><SUB>e</SUB>/8) in the Fundamental Plane results in an increase of around 15 per cent in the intrinsic scatter and an average 10 per cent decrease in the tilt away from the virial relation.</P>