86 research outputs found
[OIII] 5007A Emission Line Width as a Surrogate for stellar dispersion in Type 1 AGNs?
We present a study of the relation between the [OIII] 5007A emission line
width (sigma_{[OIII]}) and stellar velocity dispersion (sigma_{*}), utilizing a
sample of 740 type 1 active galactic nuclei (AGNs) with high-quality spectra at
redshift z < 1.0. We find the broad correlation between the core component of
[OIII] emission line width (sigma_{[OIII,core]}) and sigma_{*} with a scatter
of 0.11~dex for the low redshift (z < 0.1) sample; for redshift (0.3 < z < 1.0)
AGNs, the scatter is larger, being 0.16~dex. We also find that the Eddington
ratio (L_{bol}/L_{Edd}) may play an important role in the discrepancies between
sigma_{[OIII,core]} and sigma_{*}. As the L_{bol}/L_{Edd} increases,
sigma_{[OIII,core]} tends to be larger than sigma_{*}. By classifying our local
sample with different minor-to-major axis ratios, we find that sigma_{*} is
larger than sigma_{[OIII,core]} for those edge-on spiral galaxies. In addition,
we also find that the effects of outflow strength properties such as maximum
outflow velocity (V_{max}) and the broader component of [OIII] emission line
width and line shift (sigma_{[OIII,out]} and V_{[OIII,out]}) may play a major
role in the discrepancies between sigma_{[OIII,core]} and sigma_{*}. The
discrepancies between sigma_{[OIII,core]} and sigma_{*} are larger when
V_{max}, V_{[OIII,out]}, and sigma_{[OIII,out]} increase. Our results show that
the outflow strengths may have significant effects on the differences between
narrow-line region gas and stellar kinematics in AGNs. We suggest that caution
should be taken when using sigma_{[OIII,core]} as a surrogate for sigma_{*}. In
addition, the substitute of sigma_{[OIII,core]} for sigma_{*} could be used
only for low luminosity AGNs.Comment: 17 pages, Accepted for publication in Ap
Direct observation of ordered configurations of hydrogen adatoms on graphene
Ordered configurations of hydrogen adatoms on graphene have long been
proposed, calculated and searched for. Here we report direct observation of
several ordered configurations of H adatoms on graphene by scanning tunneling
microscopy. On the top side of the graphene plane, H atoms in the
configurations appear to stick to carbon atoms in the same sublattice. A gap
larger than 0.6 eV in the local density of states of the configurations was
revealed by scanning tunneling spectroscopy measurements. These findings can be
well explained by density functional theory calculations based on double sided
H configurations. In addition, factors that may influence H ordering are
discussed
Corticosteroid Activation of Atlantic Sea Lamprey Corticoid Receptor: Allosteric Regulation by the N-terminal Domain
Lampreys are jawless fish that evolved about 550 million years ago at the
base of the vertebrate line. Modern lampreys contain a corticoid receptor (CR),
the common ancestor of the glucocorticoid receptor (GR) and mineralocorticoid
receptor (MR), which first appear in cartilaginous fish, such as sharks. Until
recently, 344 amino acids at the amino terminus of adult lamprey CR were not
present in the lamprey CR sequence in GenBank. A search of the recently
sequenced lamprey germline genome identified two CR sequences, CR1 and CR2,
containing the 344 previously un-identified amino acids at the amino terminus.
CR1 also contains a novel four amino acid insertion in the DNA-binding domain
(DBD). We studied corticosteroid activation of CR1 and CR2 and found their
strongest response was to 11-deoxycorticosterone and 11-deoxycortisol, the two
circulating corticosteroids in lamprey. Based on steroid specificity, both CRs
are close to elephant shark MR and distant from elephant shark GR. HEK293 cells
transfected with full-length CR1 or CR2 and the MMTV promoter have about 3-fold
higher steroid-mediated activation compared to HEK293 cells transfected with
these CRs and the TAT3 promoter. Deletion of the amino-terminal domain (NTD) of
lamprey CR1 and CR2 to form truncated CRs decreased transcriptional activation
by about 70% in HEK293 cells transfected with MMTV, but increased transcription
by about 6-fold in cells transfected with TAT3, indicating that the promoter
has an important effect on NTD regulation of CR transcription by
corticosteroids.Comment: 27 pages, 6 figure
Emergent Modularity in Pre-trained Transformers
This work examines the presence of modularity in pre-trained Transformers, a
feature commonly found in human brains and thought to be vital for general
intelligence. In analogy to human brains, we consider two main characteristics
of modularity: (1) functional specialization of neurons: we evaluate whether
each neuron is mainly specialized in a certain function, and find that the
answer is yes. (2) function-based neuron grouping: we explore finding a
structure that groups neurons into modules by function, and each module works
for its corresponding function. Given the enormous amount of possible
structures, we focus on Mixture-of-Experts as a promising candidate, which
partitions neurons into experts and usually activates different experts for
different inputs. Experimental results show that there are functional experts,
where clustered are the neurons specialized in a certain function. Moreover,
perturbing the activations of functional experts significantly affects the
corresponding function. Finally, we study how modularity emerges during
pre-training, and find that the modular structure is stabilized at the early
stage, which is faster than neuron stabilization. It suggests that Transformers
first construct the modular structure and then learn fine-grained neuron
functions. Our code and data are available at
https://github.com/THUNLP/modularity-analysis.Comment: Findings of ACL 202
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