262 research outputs found
Intrinsic Alignment in redMaPPer clusters -- II. Radial alignment of satellites toward cluster centers
We study the orientations of satellite galaxies in redMaPPer clusters
constructed from the Sloan Digital Sky Survey at to determine
whether there is any preferential tendency for satellites to point radially
toward cluster centers. We analyze the satellite alignment (SA) signal based on
three shape measurement methods (re-Gaussianization, de Vaucouleurs, and
isophotal shapes), which trace galaxy light profiles at different radii. The
measured SA signal depends on these shape measurement methods. We detect the
strongest SA signal in isophotal shapes, followed by de Vaucouleurs shapes.
While no net SA signal is detected using re-Gaussianization shapes across the
entire sample, the observed SA signal reaches a statistically significant level
when limiting to a subsample of higher luminosity satellites. We further
investigate the impact of noise, systematics, and real physical isophotal
twisting effects in the comparison between the SA signal detected via different
shape measurement methods. Unlike previous studies, which only consider the
dependence of SA on a few parameters, here we explore a total of 17 galaxy and
cluster properties, using a statistical model averaging technique to naturally
account for parameter correlations and identify significant SA predictors. We
find that the measured SA signal is strongest for satellites with the following
characteristics: higher luminosity, smaller distance to the cluster center,
rounder in shape, higher bulge fraction, and distributed preferentially along
the major axis directions of their centrals. Finally, we provide physical
explanations for the identified dependences, and discuss the connection to
theories of SA.Comment: 25 pages, 16 figures, 7 tables, accepted to MNRAS. Main statistical
analysis tool changed, with the results remain simila
On the Turaev genus of torus knots
The Turaev genus and dealternating number of a link are two invariants that
measure how far away a link is from alternating. We determine the Turaev genus
of a torus knot with five or fewer strands either exactly or up to an error of
at most one. We also determine the dealternating number of a torus knot with
five or fewer strand up to an error of at most two. Additional bounds are given
on the Turaev genus and dealternating number of torus links with five or fewer
strands and on some infinite families of torus links on six strands.Comment: 24 pages, 18 figure
Federated Classification in Hyperbolic Spaces via Secure Aggregation of Convex Hulls
Hierarchical and tree-like data sets arise in many applications, including
language processing, graph data mining, phylogeny and genomics. It is known
that tree-like data cannot be embedded into Euclidean spaces of finite
dimension with small distortion. This problem can be mitigated through the use
of hyperbolic spaces. When such data also has to be processed in a distributed
and privatized setting, it becomes necessary to work with new federated
learning methods tailored to hyperbolic spaces. As an initial step towards the
development of the field of federated learning in hyperbolic spaces, we propose
the first known approach to federated classification in hyperbolic spaces. Our
contributions are as follows. First, we develop distributed versions of convex
SVM classifiers for Poincar\'e discs. In this setting, the information conveyed
from clients to the global classifier are convex hulls of clusters present in
individual client data. Second, to avoid label switching issues, we introduce a
number-theoretic approach for label recovery based on the so-called integer
sequences. Third, we compute the complexity of the convex hulls in
hyperbolic spaces to assess the extent of data leakage; at the same time, in
order to limit the communication cost for the hulls, we propose a new
quantization method for the Poincar\'e disc coupled with Reed-Solomon-like
encoding. Fourth, at server level, we introduce a new approach for aggregating
convex hulls of the clients based on balanced graph partitioning. We test our
method on a collection of diverse data sets, including hierarchical single-cell
RNA-seq data from different patients distributed across different repositories
that have stringent privacy constraints. The classification accuracy of our
method is up to better than its Euclidean counterpart,
demonstrating the importance of privacy-preserving learning in hyperbolic
spaces
Porf-2 Inhibits Neural Stem Cell Proliferation Through Wnt/β-Catenin Pathway by Its GAP Domain
Neural stem cell (NSC) proliferation and differentiation play a pivotal role in the development of brain, the plasticity of the brain network and the repair for brain function in CNS diseases. The mechanisms regulating NSC behavior are not well elucidated. Previous studies showed porf-2 functions as a modulator in central nerve system development. We here show that porf-2, a conserved family of RhoGAPs, is highly and specifically expressed in NSCs. We also demonstrate that porf-2 inhibits the proliferation of NSCs in vivo and in vitro, but has no effect on NSC differentiation. We investigated which domain is required for the role of porf-2 on NSC proliferation. By using neurosphere formation and Edu assay we confirmed the GAP domain is necessary for its function. In addition, we surveyed a few classical pathway on NSC proliferation and found that porf-2 inhibits NSC proliferation by suppressing the β-catenin nuclear translocation. Taken together, we show for the first time that porf-2 inhibits NSC proliferation through Wnt/β-catenin pathway by its GAP domain
Quality characteristics of rice inoculated with Inonotus obliquus mycelia and incubated under different cultivating conditions
This study was performed to investigate the quality characteristics of Inonotus obliquus mycelia rice incubated with I. obliquus (KCTC 256152). Different volumes of mycelial culture of I. obliquus were used for production of I. obliquus mycelia rice. Twenty percent of the mycelial culture was added to rice and designated as IOR-20, 30% as IOR-30 and 40% as IOR-40. Using the I. obliquus mycelia rice, the contents of β-1,3-glucan, betulin, total polyphenol and 1,1-diphenyl-2-picrylhydrazol (DPPH) radical scavenging activity, Hunter`s color values, free amino acid content, and mineral content were investigated. The β-1,3-glucan content in I. obliquus mycelia rice were in the order of IOR-30(729.7 μg/g) > IOR-20(716.0 μg/g) > IOR-40(690.5 μg/g) and those of betulin content were OR-30(1273.7 μg/g) > IOR-40 (1247.81 μg/g) > IOR-20 (1209.82 μg/g). The highest content of total polyphenols (353.6 μg/g) and activity of DPPH radical scavenging were observed in the IOR-30. The higher contents for β-1,3-glucan, betulin, polyphenol, and DPPH radical scavenging were found in 30% mycelial culture treatment, showing the best condition for the production of I. obliquus mycelia. Aspartic acid (10.28 to 29.44 μg/100 g), threonine (5.43 to 11.00 μg/100 g), serine (8.84 to 14.53 μg/100 g), glutamic acid (31.01 to 53.61 μg/100 g), glycine (4.77 to 10.26 μg/100 g), valine (2.93 to 6.57 μg/100 g), and lysine (5.20 to 14.41 μg/100 g) contents were determined in the I. obliquus mycelia rice and the order was as follows; IOR-20>IOR-30>IOR-40. The IOR-30 sample exhibited the highest levels of K(899.1±8.1 mg/kg), Mg(427.3±9.3 mg/kg), Ca(480.2±6.9 mg/kg), Na(296.1±9.2 mg/kg).Keywords: Rice, Inonotus obliquus (KCTC 256152), β-1,3-glucan, betulin, quality characteristicsAfrican Journal of Biotechnology Vol. 12(33), pp. 5131-513
Enhancing the heat tolerance of reef-building corals to future warming
Reef-building corals thriving in extreme thermal environments may provide genetic variation that can assist the evolution of populations to rapid climate warming. However, the feasibility and scale of genetic improvements remain untested despite ongoing population declines from recurrent thermal stress events. Here, we show that corals from the hottest reefs in the world transfer sufficient heat tolerance to a naïve population sufficient to withstand end-of-century warming projections. Heat survival increased up to 84% when naïve mothers were selectively bred with fathers from the hottest reefs because of strong heritable genetic effects. We identified genomic loci associated with tolerance variation that were enriched for heat shock proteins, oxidative stress, and immune functions. Unexpectedly, several coral families exhibited survival rates and genomic associations deviating from origin predictions, including a few naïve purebreds with exceptionally high heat tolerance. Our findings highlight previously uncharacterized enhanced and intrinsic potential of coral populations to adapt to climate warming
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