2,474 research outputs found
Statistics of the structure components in S0s: implications for bar induced secular evolution
The fractions and dimension of bars, rings and lenses are studied in the
Near-IR S0 galaxy Survey (NIRS0S). We find evidence that multiple lenses in
some barred S0s are related to bar resonances in a similar manner as the inner
and outer rings, for which the outer/inner length ratio 2. Inner lenses in the
non-barred galaxies normalized to galaxy diameter are clearly smaller than
those in the barred systems. Interestingly, these small lenses in the
non-barred galaxies have similar sizes as barlenses (lens-like structures
embedded in a bar), and therefore might actually be barlenses in former barred
galaxies, in which the outer, more elongated bar component, has been destroyed.
We also find that fully developed inner lenses are on average a factor 1.3
larger than bars, whereas inner rings have similar sizes as bars. The fraction
of inner lenses is found to be constant in all family classes (A, AB, B).
Nuclear bars appear most frequently among the weakly barred (AB) galaxies,
which is consistent with the theoretical models by Maciejewski & Athanassoula
(2008). Similar sized bars as the nuclear bars were detected in seven
'non-barred' S0s. Galaxy luminosity does not uniquely define the sizes of bars
or bar-related structures, neither is there any upper limit in galaxy
luminosity for bar formation. Although all the family classes cover the same
range of galaxy luminosity, the non-barred (A) galaxies are on average 0.6 mag
brighter than the strongly barred (B) systems. Overall, our results are
consistent with the idea that bars play an important role in the formation of
the structure components of galaxies. The fact that multiple lenses are common
in S0s, and that at least the inner lenses can have very old stellar
populations, implies that the last destructive merger, or major gas accretion
event, must have taken place at a fairly high redshift.Comment: 36 pages (include 13 figures, 11 tables). Accepted to MNRAS 2013 Jan
2
Systems cost/performance analysis (study 2.3). Volume 3: Programmer's manual and user's guide
The systems cost/performance model was implemented as a digital computer program to perform initial program planning, cost/performance tradeoffs, and sensitivity analyses. The computer is described along with the operating environment in which the program was written and checked, the program specifications such as discussions of logic and computational flow, the different subsystem models involved in the design of the spacecraft, and routines involved in the nondesign area such as costing and scheduling of the design. Preliminary results for the DSCS-II design are also included
The āmaternal effectā on epilepsy risk: Analysis of familial epilepsies and reassessment of prior evidence
Objective: Previous studies have observed that epilepsy risk is higher among offspring of affected women thanoffspring of affected men. We tested whether this āmaternal effectā was present in familial epilepsies, which areenriched for genetic factors that contribute to epilepsy risk.Methods: We assessed evidence of a maternal effect in a cohort of families containing ā„3 persons with epilepsyusing three methods: (1) ādownward-lookingā analysis, comparing the rate of epilepsy in offspring of affectedwomen versus men; (2) āupward-lookingā analysis, comparing the rate of the epilepsy among mothers versusfathers of affected individuals; (3) lineage analysis, comparing the the proportion of affected individuals withfamily history of epilepsy on the maternal versus paternal side.Results: Downward-looking analysis revealed no difference in epilepsy rates among offspring of affectedmothers versus fathers (prevalence ratio 1.0, 95% CI 0.8, 1.2). Upward-looking analysis revealed more affectedmothers than affected fathers; this effect was similar for affected and unaffected sibships (odds ratio 0.8, 95%CI 0.5, 1.2) and was explained by a combination of differential fertility and participation rates. Lineage analysisrevealed no significant difference in the likelihood of maternal versus paternal family history of epilepsy.Interpretation: We found no evidence of a maternal effect on epilepsy risk in this familial epilepsy cohort.Confounding sex imbalances can create the appearance of a maternal effect in upward-looking analyses andmay have impacted prior studies. We discuss possible explanations for the lack of evidence, in familialepilepsies, of the maternal effect observed in population-based studie
Bandit optimisation of functions in the Mat\'ern kernel RKHS
We consider the problem of optimising functions in the reproducing kernel
Hilbert space (RKHS) of a Mat\'ern kernel with smoothness parameter over
the domain under noisy bandit feedback. Our contribution, the
-GP-UCB algorithm, is the first practical approach with guaranteed
sublinear regret for all and . Empirical validation suggests
better performance and drastically improved computational scalablity compared
with its predecessor, Improved GP-UCB.Comment: AISTATS 2020, camera read
DYNAMICS OF RODENT ASSEMBLAGES INHABITING ABANDONED PETROLEUM LANDFARMS IN OKLAHOMA
Studies on the effects of anthropogenic contamination on wildlife have largely been focused at the individual level. Biomarkers have been used to monitor changes in the health of individuals exposed to contaminants; however, little attention has been given to the effects of chronic exposure at the population or community levels. We studied rodent assemblages from uncontaminated (reference) sites (n 5 5) and abandoned petrochemical landfarms (n 5 5) in Oklahoma to investigate potential alterations in community structure and composition. Rodent assemblages inhabiting landfarms had lower species diversity, lower richness, and a more even distribution of individuals across species. Reference sites showed typical rodent assemblage structure dominated by hispid cotton rats (Sigmodon hispidus) and fulvous harvest mice (Reithrodontomys fulvescens). Assemblages inhabiting landfarms also were dominated by cotton rats; however, harvest mice were replaced by deer mice (Peromyscus maniculatus) on two landfarms. Contaminated sites also were characterized by an increase in house mice (Mus musculus) and an absence of voles (Microtus spp.). Although landfarms tended to have lower cotton rat densities, we could not separate the effects of contamination from increased bare ground associated with landfarms. The results of this study suggest that rodent assemblages were different on landfarms, when compared with reference sites. However, no direct link between site contamination and rodent community structure could be established
Syntaxin 3B is essential for the exocytosis of synaptic vesicles in ribbon synapses of the retina.
Ribbon synapses of the vertebrate retina are specialized synapses that release neurotransmitter by synaptic vesicle exocytosis in a manner that is proportional to the level of depolarization of the cell. This release property is different from conventional neurons, in which the release of neurotransmitter occurs as a short-lived burst triggered by an action potential. Synaptic vesicle exocytosis is a calcium regulated process that is dependent on a set of interacting synaptic proteins that form the so-called SNARE (soluble N-ethylmaleimide sensitive factor attachment protein receptor) complex. Syntaxin 3B has been identified as a specialized SNARE molecule in ribbon synapses of the rodent retina. However, the best physiologically-characterized neuron that forms ribbon-style synapses is the rod-dominant or Mb1 bipolar cell of the goldfish retina. We report here the molecular characterization of syntaxin 3B from the goldfish retina. Using a combination of reverse transcription (RT) polymerase chain reaction (PCR) and immunostaining with a specific antibody, we show that syntaxin 3B is highly enriched in the plasma membrane of bipolar cell synaptic terminals of the goldfish retina. Using membrane capacitance measurements we demonstrate that a peptide derived from goldfish syntaxin 3B inhibits synaptic vesicle exocytosis. These experiments demonstrate that syntaxin 3B is an important factor for synaptic vesicle exocytosis in ribbon synapses of the vertebrate retina
REFLEXIONEN UBER GESELLSCHAFT OHNE RELIGION: DER FALL ALBANIEN
AnalizirajuÄi proces sekularizacije u modernim druÅ”tvima, autor
postavlja tezu o druŔtvu bez religije te je problematizira i argumentira
analizom sluÄaja Albanije. Iznimno visok stupanj sekulariziranosti
albanskoga druŔtva posljedica je "hiperstaljinizma" - ideologije
bivÅ”eg komunistiÄkog režima, potom politike krajnjeg izolacionizma
toga režima, te konaÄno brutalne represije prema vjernicima i vjerskim
institucijama. AnalizirajuÄi navedene uzroke iÅ”ÄeznuÄa religije
u Albaniji, autor primjeÄuje da niti nakon sloma komunizma i demokratizacije
albanskog druÅ”tva te unatoÄ vjerskoj propagandi razliÄitih
konfesija, u toj zemlji ne dolazi do obnove vjerskog života. BuduÄi
da je proces uznapredovale sekularizacije primjetan ne samo u takvim
zemljama, podložnim protuvjerskoj propagandi i represiji, nego
i u nekim zapadnim demokratskim zemljama, autor na temelju tih
Äinjenica postavlja pitanje o biti religije i sekularizacije te o mjestu
tih fenomena u ljudskoj naravi i druÅ”tvu uopÄe.ln analyzing the process of secularization in modern societies, the
author proposes the hypothesis about society without religion and
presents his arguments by problematizing Albania\u27s case. The extremely
high degree of secularization of Albanian society is a consequence
of hyper-Stallinism - the ideology of the former communist
regime, the result of the regime\u27s policy of extreme isolationism, and
finally of brutal repression towards religious people and institutions.
By analyzing the mentioned causes of the disappearance of religion
in Albania, the author notices that even after the fall of communism
and the democratization of Albanian society, and inspite of religious
propaganda of different confessions, the renewal of religious life
has not occured. Due to the fact that the process of advanced secularization
is not only evident in these countries, which are subject
to anti-religious propaganda and repression, but also in some western
democratic countries, the author, based on these facts, questions
the essence of religion and secularization and the place of these
phenomena in human nature and society in general.Der Verfasser analysiert den in modernen Gesellschaften nachvollziehbaren
SakutarisienmqsprozefÅ” und stellt die These von Gesellschaft
ohne Religion auf, die er am Beispiel des Falls Albanien
problematisiert und argumentiert. Der ausnehmend hohe Saku larisierungsgrad
der albanischen Gesellschaft ist eine Konsequenz
des Hyperstalinismus Ä der ldeologie des ehemaligen kommunistischen
Regimes und seiner extremen Isolationspolitik, verbunden
mit brutaler Repression gegenOber Glaubiqen und reliqiÄsen Institutionen.
Bei seiner Analyse der angeWhrten Faktoren, die zum
Verschwinden der Religion in Albanien gefOhrt haben, stellt der Verfasser
fest, daB es in diesem Land auch nach dem Zerfall des Kommunismus
und der Demokratisierung der albanischen Gesellschaft
und trotz der Propaganda verschiedener Konfessionen nicht zu einer
Erneuerung reliqiÄsen Lebens gekommen ist. Der ProzeB fortgeschrittener
Sakularisierunq ist nicht nur in tandem bemerbar, die
antireliqiÄser Propaganda und Repressionen ausgesetzt sind, sondern
auch in einigen demokratischen Landern des Westens. Der
Verfasser stellt aufgrund dessen die Frage nach dem Wesen der
Religion und der Sakutarisierunq, ferner nach dem Ort dieser Phanomene
in der menschlichen Natur und der Gesellschaft Oberhaupt
LEDA 074886: A remarkable rectangular-looking galaxy
We report the discovery of an interesting and rare, rectangular-shaped
galaxy. At a distance of 21 Mpc, the dwarf galaxy LEDA 074886 has an absolute
R-band magnitude of -17.3 mag. Adding to this galaxy's intrigue is the presence
of an embedded, edge-on stellar disk (of extent 2R_{e,disk} = 12 arcsec = 1.2
kpc) for which Forbes et al. reported V_rot/sigma ~ 1.4. We speculate that this
galaxy may be the remnant of two (nearly edge-one) merged disk galaxies in
which the initial gas was driven inward and subsequently formed the inner disk,
while the stars at larger radii effectively experienced a dissipationless
merger event resulting in this `emerald cut galaxy' having very boxy isophotes
with a_4/a = -0.05 to -0.08 from 3 to 5 kpc. This galaxy suggests that
knowledge from simulations of both `wet' and `dry' galaxy mergers may need to
be combined to properly understand the various paths that galaxy evolution can
take, with a particular relevance to blue elliptical galaxies.Comment: To appear in ApJ. Six pages including references and figure
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