3,869 research outputs found
Spectral Line De-confusion in an Intensity Mapping Survey
Spectral line intensity mapping has been proposed as a promising tool to
efficiently probe the cosmic reionization and the large-scale structure.
Without detecting individual sources, line intensity mapping makes use of all
available photons and measures the integrated light in the source confusion
limit, to efficiently map the three-dimensional matter distribution on large
scales as traced by a given emission line. One particular challenge is the
separation of desired signals from astrophysical continuum foregrounds and line
interlopers. Here we present a technique to extract large-scale structure
information traced by emission lines from different redshifts, embedded in a
three-dimensional intensity mapping data cube. The line redshifts are
distinguished by the anisotropic shape of the power spectra when projected onto
a common coordinate frame. We consider the case where high-redshift [CII] lines
are confused with multiple low-redshift CO rotational lines. We present a
semi-analytic model for [CII] and CO line estimates based on the cosmic
infrared background measurements, and show that with a modest instrumental
noise level and survey geometry, the large-scale [CII] and CO power spectrum
amplitudes can be successfully extracted from a confusion-limited data set,
without external information. We discuss the implications and limits of this
technique for possible line intensity mapping experiments.Comment: 13 pages, 14 figures, accepted by Ap
The clathrin-binding motif and the J-domain of Drosophila Auxilin are essential for facilitating Notch ligand endocytosis
<p>Abstract</p> <p>Background</p> <p>Ligand endocytosis plays a critical role in regulating the activity of the Notch pathway. The <it>Drosophila </it>homolog of auxilin (<it>dAux</it>), a J-domain-containing protein best known for its role in the disassembly of clathrin coats from clathrin-coated vesicles, has recently been implicated in Notch signaling, although its exact mechanism remains poorly understood.</p> <p>Results</p> <p>To understand the role of auxilin in Notch ligand endocytosis, we have analyzed several point mutations affecting specific domains of dAux. In agreement with previous work, analysis using these stronger <it>dAux </it>alleles shows that dAux is required for several Notch-dependent processes, and its function during Notch signaling is required in the signaling cells. In support of the genetic evidences, the level of Delta appears elevated in <it>dAux </it>deficient cells, suggesting that the endocytosis of Notch ligand is disrupted. Deletion analysis shows that the clathrin-binding motif and the J-domain, when over-expressed, are sufficient for rescuing <it>dAux </it>phenotypes, implying that the recruitment of Hsc70 to clathrin is a critical role for dAux. However, surface labeling experiment shows that, in <it>dAux </it>mutant cells, Delta accumulates at the cell surface. In <it>dAux </it>mutant cells, clathrin appears to form large aggregates, although Delta is not enriched in these aberrant clathrin-positive structures.</p> <p>Conclusion</p> <p>Our data suggest that <it>dAux </it>mutations inhibit Notch ligand internalization at an early step during clathrin-mediated endocytosis, before the disassembly of clathrin-coated vesicles. Further, the inhibition of ligand endocytosis in <it>dAux </it>mutant cells possibly occurs due to depletion of cytosolic pools of clathrin via the formation of clathrin aggregates. Together, our observations argue that ligand endocytosis is critical for Notch signaling and auxilin participates in Notch signaling by facilitating ligand internalization.</p
Recommended from our members
Draft Whole-Genome Sequences of Xylella fastidiosa subsp. fastidiosa Strains TPD3 and TPD4, Isolated from Grapevines in Hou-li, Taiwan.
We report the draft assemblies of TPD3 and TPD4, two Xylella fastidiosa subsp. fastidiosa isolates infecting grapevines in Hou-li, Taiwan. TPD3 and TPD4 showed similar characteristics regarding genome size (2,483,503 bp and 2,491,539 bp, respectively), GC content (51.49% and 51.47%, respectively), and number of protein-coding sequences (2,394 and 2,413, respectively)
Recommended from our members
Discussion On Device Structures And Hermetic Encapsulation For SiOx Random Access Memory Operation In Air
An edge-free structure and hermetic encapsulation technique are presented that enable SiOx-based resistive random-access memory (RRAM) operation in air. A controlled etch study indicates that the switching filament is close to the SiOx surface in devices with an exposed SiOx edge. Electrical test of encapsulated, edge-free devices in 1 atmosphere air indicates stable switching characteristics, unlike devices with an edge. This work demonstrates that SiOx RRAM is able to operate in air with proper encapsulation and an edge-free structure. The resistive switching failure mechanism when operating in air is explained by the oxidation of hydrogen-complexed defects in the switching filament. (C) 2014 AIP Publishing LLC.National Science Foundation IIP-1127537Microelectronics Research Cente
HOW TO OVERCOME ANALPHABETISM IN READING CHINESE CHARACTER
Most languages in the world use some system of alphabetical characters: Latin, Greek, Cyrillic, Hebrew, Arabic, Hindi and so on. A foreigner that does not know the language can get some information from a written text provided he knows the alphabet and disposes of a dictionary. When there is no longer an alphabet, but only pictorial characters, the problem becomes at first unsolvable. Chinese is the main language where an ignorant foreigner is completely analphabet. Fortunately there are methods that after some training allow the recognition of pictorial characters. In our university some twenty pupils of the Excellence School participated to an experiment of Chinese alphabetization gluing a traditional practical Chinese first course with information theory methods for dealing with image data bases. In this article first we discuss both the theoretical foundations. Then we give a report of the merging of the two conceptual schemes as it was performed at the excellence school. Finally we draw some conclusions about improvements of the method
An efficient surrogate model for emulation and physics extraction of large eddy simulations
In the quest for advanced propulsion and power-generation systems,
high-fidelity simulations are too computationally expensive to survey the
desired design space, and a new design methodology is needed that combines
engineering physics, computer simulations and statistical modeling. In this
paper, we propose a new surrogate model that provides efficient prediction and
uncertainty quantification of turbulent flows in swirl injectors with varying
geometries, devices commonly used in many engineering applications. The novelty
of the proposed method lies in the incorporation of known physical properties
of the fluid flow as {simplifying assumptions} for the statistical model. In
view of the massive simulation data at hand, which is on the order of hundreds
of gigabytes, these assumptions allow for accurate flow predictions in around
an hour of computation time. To contrast, existing flow emulators which forgo
such simplications may require more computation time for training and
prediction than is needed for conducting the simulation itself. Moreover, by
accounting for coupling mechanisms between flow variables, the proposed model
can jointly reduce prediction uncertainty and extract useful flow physics,
which can then be used to guide further investigations.Comment: Submitted to JASA A&C
STRUCTURES AND PATHS FOR THE EXPLORATION OF LANDSCAPE – CULTURAL MOSAIC
The main aim of this paper is to highlight the evolution of urban and peri-urban networks in view of their use by dwellers and visitors. It considers the knowledge as a part of a hidden permanent education form, and as a prerequisite for full enjoyment of available culture, sport and health facilities. Although, the objectives of the inhabitants and tourists are very different, their basic structural needs and the underlying methodology have common characteristics. In this prospective, the central element is the ability to build networks that connect the nodes of interest, which are functional (services at various levels), cultural (historical and artistic emerging features), and leisure (dedicated sport facilities and locations). Furthermore, the paper investigates the paths and times of networks connections, providing particular attention to multipurpose trips consistence of either dwellers or tourists
- …