8,618 research outputs found
Using DREADD to Examine the Role of Infralimbic Gq-coupled Receptors in Fear Acquisition
Post-Traumatic Stress Disorder (PTSD) can develop after a person experiences a very traumatic event that produces a strong and long-lasting aversive memory. During any given year, approximately 8 million adults will suffer from PTSD. Existing treatments often fail to achieve a full extinction of the traumatic fear the patients re-experience. Consequently, how the brain processes and modulates fear memories continues to be an active area of research. The excitability of the infralimbic cortex (IL), a sub-region of the medial prefrontal cortex, is important for fear extinction. Previous studies done in our lab found that Gq-coupled receptors located in this region of the brain, specifically muscarinic and mGluR5 receptors play a critical role in the consolidation of extinction memory. However, their effect on the acquisition of fear is still unknown.
Thus, the main purpose of this research is to determine whether the activation of Gq-coupled receptors in IL prior to the learning of fear affects fear memory. We hypothesized that stimulation of these receptors during fear conditioning would decrease acquired fear. To test this, we utilized a pharmacogenetic approach in the form of Designer Receptors Exclusively Activated by Designer Drugs (DREADD), which allow for controlled manipulation of the desired area in the brain using the selective agonist CNO. Adult male Sprague Dawley rats were surgically infused with a virus, which expressed a Gq-coupled DREADD. Three weeks later, the rats will be injected with CNO one hour prior to behavioral training and sacrificed for immunohistochemistry to examine neuronal activity
RDF-TR: Exploiting structural redundancies to boost RDF compression
The number and volume of semantic data have grown impressively over the last decade, promoting compression as an essential tool for RDF preservation, sharing and management. In contrast to universal compressors, RDF compression techniques are able to detect and exploit specific forms of redundancy in RDF data. Thus, state-of-the-art RDF compressors excel at exploiting syntactic and semantic redundancies, i.e., repetitions in the serialization format and information that can be inferred implicitly. However, little attention has been paid to the existence of structural patterns within the RDF dataset; i.e. structural redundancy. In this paper, we analyze structural regularities in real-world datasets, and show three schema-based sources of redundancies that underpin the schema-relaxed nature of RDF. Then, we propose RDF-Tr (RDF Triples Reorganizer), a preprocessing technique that discovers and removes this kind of redundancy before the RDF dataset is effectively compressed. In particular, RDF-Tr groups subjects that are described by the same predicates, and locally re-codes the objects related to these predicates. Finally, we integrate
RDF-Tr with two RDF compressors, HDT and k2-triples. Our experiments show that using RDF-Tr with these compressors improves by up to 2.3 times their original effectiveness, outperforming the most prominent state-of-the-art techniques
Structural properties of various sodium thiogermanate glasses through DFT-based molecular dynamics simulations
We present a study of the structural properties of (x)NaS-(1-x)GeS
glasses through DFT-based molecular dynamics simulations, at different sodium
concentrations (). We computed the radial pair correlation functions
as well as the total and partial structure factors. We also analyzed the
evolution of the corner- and edge-sharing intertetrahedral links with the
sodium concentration and show that the sodium ions exclusively destroy the
former. With the increase of the sodium concentration the ``standard'' FSDP
disappears and a new pre-peak appears in the structure factor which can be
traced back in the Na-Na partial structure factor. This self organization of
the sodium ions is coherent with Na-rich zones that we find at high modifier
concentration.Comment: 9 pages, 7 figures; to be published in Phys. Rev.
Yield Components in Annual Ryegrass and Oats Grown in Association and Monoculture
Earliness of oats and higher growth rate of annual ryegrass later in the season explain the higher forage yield of annual ryegrass+oats association over monocultures (Améndola & Morales, 1997). However, changes in yield components of the species grown in association compared to monoculture have not been explored. This study aimed to determine leaf, stem and dead matter yield in annual ryegrass and oats when grown in association and monoculture at different nitrogen (N) levels
The UNAM-KIAS Catalog of Isolated Galaxies
A new catalog of isolated galaxies from The Sloan Digital Sky Survey (DR5) is
presented. 1520 isolated galaxies were found in 1.4 steradians of sky. The
selection criteria in this so called UNAM-KIAS catalog was implemented from a
variation on the criteria developed by Karachentseva 1973 including full
redshift information. Through an image processing pipeline that takes advantage
from the high resolution (~ 0.4 ''/pix) and high dynamic range of the SDSS
images, a uniform g band morphological classification for all these galaxies is
presented. We identify 80% (SaSm) spirals (50% later than Sbc types) on one
hand, and a scarce population of early-type E(6.5%) and S0(8%) galaxies
amounting to 14.5% on the other hand. This magnitude-limited catalog is ~ 80%
complete at 16.5, 15.6, 15.0, 14.6 and 14.4 magnitudes in the ugriz bands
respectively. Some representative physical properties including SDSS magnitudes
and color distributions, color-color diagrams, absolute magnitude-color, and
concentration-color diagrams as a function of morphological type are presented.
The UNAM-KIAS Morphological Atlas is also released along with this paper. For
each galaxy of type later than Sa, a mosaic is presented that includes: (1) a
g-band logarithmic image, (2) a g band filtered-enhanced image where a Gaussian
kernel of various sizes was applied and (3) an RGB color image from the SDSS
database. For E/S0/Sa galaxies, in addition to the images in (1), (2) and (3),
plots of r band surface brightness and geometric profiles (ellipticity,
Position Angle PA and A4/B4 coefficients of the Fourier series expansions of
deviations of a pure ellipse) are provided...Comment: 40 pages, 17 figures and 3 table
The UNAM-KIAS Catalog of Isolated Galaxies
A new catalog of isolated galaxies from The Sloan Digital Sky Survey (DR5) is
presented. 1520 isolated galaxies were found in 1.4 steradians of sky. The
selection criteria in this so called UNAM-KIAS catalog was implemented from a
variation on the criteria developed by Karachentseva 1973 including full
redshift information. Through an image processing pipeline that takes advantage
from the high resolution (~ 0.4 ''/pix) and high dynamic range of the SDSS
images, a uniform g band morphological classification for all these galaxies is
presented. We identify 80% (SaSm) spirals (50% later than Sbc types) on one
hand, and a scarce population of early-type E(6.5%) and S0(8%) galaxies
amounting to 14.5% on the other hand. This magnitude-limited catalog is ~ 80%
complete at 16.5, 15.6, 15.0, 14.6 and 14.4 magnitudes in the ugriz bands
respectively. Some representative physical properties including SDSS magnitudes
and color distributions, color-color diagrams, absolute magnitude-color, and
concentration-color diagrams as a function of morphological type are presented.
The UNAM-KIAS Morphological Atlas is also released along with this paper. For
each galaxy of type later than Sa, a mosaic is presented that includes: (1) a
g-band logarithmic image, (2) a g band filtered-enhanced image where a Gaussian
kernel of various sizes was applied and (3) an RGB color image from the SDSS
database. For E/S0/Sa galaxies, in addition to the images in (1), (2) and (3),
plots of r band surface brightness and geometric profiles (ellipticity,
Position Angle PA and A4/B4 coefficients of the Fourier series expansions of
deviations of a pure ellipse) are provided...Comment: 40 pages, 17 figures and 3 table
- …