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GLOBULAR CLUSTER POPULATIONS: RESULTS INCLUDING S<sup>4</sup>G LATE-TYPE GALAXIES
Zaritsky, Dennis,McCabe, Kelsey,Aravena, Manuel,Athanassoula, E.,Bosma, Albert,Comeró,n, Sé,bastien,Courtois, Helene M.,Elmegreen, Bruce G.,Elmegreen, Debra M.,Erroz-Ferrer, Santiago,Gadot American Astronomical Society 2016 The Astrophysical journal Vol.818 No.1
<P>Using 3.6 and 4.5 mu m images of 73 late-type, edge-on galaxies from the S(4)G survey, we compare the richness of the globular cluster populations of these galaxies to those of early-type galaxies that we measured previously. In general, the galaxies presented here fill in the distribution for galaxies with lower stellar mass, M-*, specifically log(M-*/M-circle dot) < 10, overlap the results for early-type galaxies of similar masses, and, by doing so, strengthen the case for a dependence of the number of globular clusters per 10(9)M(circle dot) of galaxy stellar mass, T-N, on M-*. For 8.5 < log(M-*/M-circle dot) < 10.5 we find the relationship can be satisfactorily described as T-N = (M-*/10(6.7))(-0.56) M-* is expressed in solar masses. The functional form of the relationship is only weakly constrained, and extrapolation outside this range is not advised. Our late-type galaxies, in contrast to our early types, do not show the tendency for low-mass galaxies to split into two T-N families. Using these results and a galaxy stellar mass function from the literature, we calculate that, in a volume-limited, local universe sample, clusters are most likely to be found around fairly massive galaxies (M-* similar to 10(10.8)M(circle dot)) and present a fitting function for the volume number density of clusters as a function of parent-galaxy stellar mass. We find no correlation between T-N and large-scale environment, but we do find a tendency for galaxies of fixed M-* to have larger T-N if they have converted a larger proportion of their baryons into stars.</P>
Contreras, Yanett,Sanhueza, Patricio,Jackson, James M.,Guzmá,n, André,s E.,Longmore, Steven,Garay, Guido,Zhang, Qizhou,Nguyê,̃,n-Lu’o’, Quang,Tatematsu, Ken’ichi,Nakamura, Fumita American Astronomical Society 2018 The Astrophysical journal Vol.861 No.1
<P>Using Galactic Plane surveys, we have selected a massive (1200M circle dot), cold (14 K) 3.6-70 mu m dark IRDC, G331.372-00.116. This infrared dark cloud (IRDC) has the potential to form high-mass stars, and given the absence of current star formation signatures, it seems to represent the earliest stages of high-mass star formation. We have mapped the whole IRDC with the Atacama Large Millimeter/submillimeter Array (ALMA) at 1.1 and 1.3 mm in dust continuum and line emission. The dust continuum reveals 22 cores distributed across the IRDC. In this work, we analyze the physical properties of the most massive core, ALMA1, which has no molecular outflows detected in the CO (2-1), SiO (5-4), and H2CO (3-2) lines. This core is relatively massive (M = 17.6M circle dot), subvirialized (virial parameter alpha(vir) = M-vir/M = 0.14), and is barely affected by turbulence (transonic Mach number of 1.2). Using the HCO+ (3-2) line, we find the first detection of infall signatures in a relatively massive, prestellar core (ALMA1) with the potential to form a high-mass star. We estimate an infall speed of 1.54 km s(-1) and a high accretion rate of 1.96. x. 10(-3) M circle dot yr(-1). ALMA1 is rapidly collapsing, out of virial equilibrium, which is more consistent with competitive accretion scenarios rather than the turbulent core accretion model. On the other hand, ALMA1 has a mass similar to 6 times larger than the clumps Jeans mass, as it is in an intermediate mass regime (M-J = 2.7 < M less than or similar to 30 M circle dot), contrary to what both the competitive accretion and turbulent core accretion theories predict.</P>
Imaging chiral symmetry breaking from Kekulé bond order in graphene
Gutié,rrez, Christopher,Kim, Cheol-Joo,Brown, Lola,Schiros, Theanne,Nordlund, Dennis,Lochocki, Edward ,B.,Shen, Kyle M.,Park, Jiwoong,Pasupathy, Abhay N. Nature Publishing Group, a division of Macmillan P 2016 NATURE PHYSICS Vol.12 No.10
Chirality—or ‘handedness’—is a symmetry property crucial to fields as diverse as biology, chemistry and high-energy physics. In graphene, chiral symmetry emerges naturally as a consequence of the carbon honeycomb lattice. This symmetry can be broken by interactions that couple electrons with opposite momenta in graphene. Here we directly visualize the formation of Kekulé bond order, one such phase of broken chiral symmetry, in an ultraflat graphene sheet grown epitaxially on a copper substrate. We show that its origin lies in the interactions between individual vacancies in the copper substrate that are mediated electronically by the graphene. We show that this interaction causes the bonds in graphene to distort, creating a phase with broken chiral symmetry. The Kekulé ordering is robust at ambient temperature and atmospheric conditions, indicating that intercalated atoms may be harnessed to drive graphene and other two-dimensional materials towards electronically desirable and exotic collective phases.
Valdé,s Herná,ndez, Maria del Carmen,Cox, Simon R.,Kim, Jaeil,Royle, Natalie A.,Muñ,oz Maniega, Susana,Gow, Alan J.,Anblagan, Devasuda,Bastin, Mark E.,Park, Jinah,Starr, John M.,Ward Elsevier 2017 NEUROBIOLOGY OF AGING Vol.52 No.-
<P>Structural measures of the hippocampus have been linked to a variety of memory processes and also to broader cognitive abilities. Gross volumetry has been widely used, yet the hippocampus has a complex formation, comprising distinct subfields which may be differentially sensitive to the deleterious effects of age, and to different aspects of cognitive performance. However, a comprehensive analysis of multidomain cognitive associations with hippocampal deformations among a large group of cognitively normal older adults is currently lacking. In 654 participants of the Lothian Birth Cohort 1936 (mean age = 72.5, SD = 0.71 years), we examined associations between the morphology of the hippocampus and a variety of memory tests (spatial span, letter-number sequencing, verbal recall, and digit backwards), as well as broader cognitive domains (latent measures of speed, fluid intelligence, and memory). Following correction for age, sex, and vascular risk factors, analysis of memory subtests revealed that only right hippocampal associations in relation to spatial memory survived type 1 error correction in subiculum and in CA1 at the head (<I>β</I> = 0.201, <I>p</I> = 5.843 × 10<SUP>−4</SUP>, outward), and in the ventral tail section of CA1 (<I>β</I> = −0.272, <I>p</I> = 1.347 × 10<SUP>−5</SUP>, inward). With respect to latent measures of cognitive domains, only deformations associated with processing speed survived type 1 error correction in bilateral subiculum (<I>β</I><SUB><I>absolute</I></SUB> ≤ 0.247, <I>p</I> < 1.369 × 10<SUP>−4</SUP>, outward), bilaterally in the ventral tail section of CA1 (<I>β</I><SUB><I>absolute</I></SUB> ≤ 0.242, <I>p</I> < 3.451 × 10<SUP>−6</SUP>, inward), and a cluster at the left anterior-to-dorsal region of the head (<I>β</I> = 0.199, <I>p</I> = 5.220 × 10<SUP>−6</SUP>, outward). Overall, our results indicate that a complex pattern of both inward and outward hippocampal deformations are associated with better processing speed and spatial memory in older age, suggesting that complex shape-based hippocampal analyses may provide valuable information beyond gross volumetry.</P>
Spiral density waves in a young protoplanetary disk
Pé,rez, Laura M.,Carpenter, John M.,Andrews, Sean M.,Ricci, Luca,Isella, Andrea,Linz, Hendrik,Sargent, Anneila I.,Wilner, David J.,Henning, Thomas,Deller, Adam T.,Chandler, Claire J.,Dullemond, American Association for the Advancement of Scienc 2016 Science Vol.353 No.6307
<P>Gravitational forces are expected to excite spiral density waves in protoplanetary disks, disks of gas and dust orbiting young stars. However, previous observations that showed spiral structure were not able to probe disk midplanes, where most of the mass is concentrated and where planet formation takes place. Using the Atacama Large Millimeter/submillimeter Array, we detected a pair of trailing symmetric spiral arms in the protoplanetary disk surrounding the young star Elias 2-27. The arms extend to the disk outer regions and can be traced down to the midplane. These millimeter-wave observations also reveal an emission gap closer to the star than the spiral arms. We argue that the observed spirals trace shocks of spiral density waves in the midplane of this young disk.</P>
Explaining nonlinear classification decisions with deep Taylor decomposition
Montavon, Gré,goire,Lapuschkin, Sebastian,Binder, Alexander,Samek, Wojciech,Mü,ller, Klaus-Robert Elsevier 2017 Pattern recognition Vol.65 No.-
<P><B>Abstract</B></P> <P>Nonlinear methods such as Deep Neural Networks (DNNs) are the gold standard for various challenging machine learning problems such as image recognition. Although these methods perform impressively well, they have a significant disadvantage, the lack of transparency, limiting the interpretability of the solution and thus the scope of application in practice. Especially DNNs act as black boxes due to their multilayer nonlinear structure. In this paper we introduce a novel methodology for interpreting generic multilayer neural networks by decomposing the network classification decision into contributions of its input elements. Although our focus is on image classification, the method is applicable to a broad set of input data, learning tasks and network architectures. Our method called deep Taylor decomposition efficiently utilizes the structure of the network by backpropagating the explanations from the output to the input layer. We evaluate the proposed method empirically on the MNIST and ILSVRC data sets.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A novel method to explain nonlinear classification decisions in terms of input variables is introduced. </LI> <LI> The method is based on Taylor expansions and decomposes the output of a deep neural network in terms of input variables. </LI> <LI> The resulting deep Taylor decomposition can be applied directly to existing neural networks without retraining. </LI> <LI> The method is tested on two large-scale neural networks for image classification: BVLC CaffeNet and GoogleNet. </LI> </UL> </P>
Karen M. Jimé,nez,Angela J. Pereira Morales,Diego A. Forero 대한신경정신의학회 2018 PSYCHIATRY INVESTIGATION Vol.15 No.4
Objective-The aim of this study was to examine a possible association between depressive symptoms and a functional polymorphism (rs686) that modulates the regulation of DRD1 gene by miR-504. Methods-A total of 239 young Colombian subjects were evaluated with the Patient Health Questionnaire-9 (PHQ-9) scale and geno-typed for the rs686 polymorphism. A linear regression model, corrected by age and gender, was used. Results-A significant association between the rs686 polymorphism and PHQ-9 scores was found, under a dominant genetic model (p=0.0094). Conclusion-These results provide novel evidence about the growing role of inherited variants in binding sites for brain-expressed miRNAs on depressive symptomatology