650 research outputs found
Isolation of a transcriptionally active element of high copy number retrotransposons in sweetpotato genome
Many plant retrotransposons have been characterized, but only three families (Tnt1, Tto1 and
Tos17) have been demonstrated to be transpositionally competent. We followed a novel approach
that enabled us to identify an active element of the Ty1-copia retrotransposon family with
estimated 400 copies in the sweetpotato genome. DNA sequences of Ty1 -copia reverse
transcriptase (RTase) from the sweetpotato genome were analyzed, and a group of
retrotransposon copies probably formed by recent transposition events was further analyzed.
3’RACE on callus cDNA amplified transcripts containing long terminal repeats (LTR) of this
group. The sequence -specific amplification polymorphism (S-SAP) patterns of the LTR sequence
in the genomic DNA were compared between a normal plant and callus lines derived from it. A
callus -specific S-SAP product was found into which the retrotransposon detected by the 3’RACE
had been transposed apparently during cell culture. We conclude that our approach provides an
effective way to identify active elements of retrotransposons with high copy numbers.</p
Spectroscopic Observations of the Outflowing Wind in the Lensed Quasar SDSS J1001+5027
We performed spectroscopic observations of the small-separation lensed quasar
SDSS J1001+5027, whose images have an angular separation , and placed constraints on the physical properties of
gas clouds in the vicinity of the quasar (i.e., in the outflowing wind launched
from the accretion disk). The two cylinders of sight to the two lensed images
go through the same region of the outflowing wind and they become fully
separated with no overlap at a very large distance from the source (
pc). We discovered a clear difference in the profile of the CIV broad
absorption line (BAL) detected in the two lensed images in two observing
epochs. Because the kinematic components in the BAL profile do not vary in
concert, the observed variations cannot be reproduced by a simple change of
ionization state. If the variability is due to gas motion around the background
source (i.e., the continuum source), the corresponding rotational velocity is
km/s, and their distance from the source is
pc assuming Keplerian motion. Among three MgII and three CIV NAL systems that
we detected in the spectra, only the MgII system at shows a
hint of variability in its MgI profile on a rest-frame time scale of days and an obvious velocity shear between the sightlines
whose physical separation is kpc. We interpret this as the result of
motion of a cosmologically intervening absorber, perhaps located in a
foreground galaxy.Comment: 15 pages, including 7 figures; accepted for publication in the
Astrophysical Journa
Electrochemical Oxidation of Glucose Using Copper Hydroxide Nanosheets
In this study, we synthesized copper hydroxide nanosheet and investigated electrochemical oxidation of glucose using the copper hydroxide nanosheets. The precursor of the nanosheet was a layered copper hydroxide synthesized by the ion exchange of dodecylbenzene sulfonate with acetate in Cu2(OH)3(CH3COO)·H2O. Delamination of the layered copper hydroxide prepared the nanosheet by dispersion in 1-butanol. Atomic force microscopy images of the nanosheets showed lateral dimensions of ca. 2 μm with a height of ca. 4.5 nm. Cyclic voltammogram of the nanosheet coated electrode showed oxidation current peak depend on the concentration of glucose at around +0.6 V vs. Ag/AgCl. Amperometry was measured at +0.6V vs. Ag/AgCl with successive addition of glucose solution. Glucose concentration and catalytic current were almost proportional. When the linear range is 0.1 to 4.9 mM, the sensitivity was 1.16 mA mM-1cm-2 from the slope
Behavior-based price discrimination and elastic demand
Existing studies on Behaviour-based price discrimination (BBPD) typically show that firms offer discounts to encourage consumers located middle of the line segment to switch in a duopoly model. However, in practice, some firms offer both this discount and a discount to encourage consumers with lower preferences for
the product itself to buy at the same time. I introduce heterogeneity of consumer willingness to pay and relax the assumption that the market is fully covered. Then, there are three purchase histories: bought from a firm, bought from another firm, and bought nothing. I assume that the two firms offer three different prices according to the purchase histories under BBPD. In the second period, firms offer discounts not only for rival customers but also for customers who bought nothing. On the other hand, firms offer higher prices for consumers who purchase the same goods over two periods in the second period than in the first period. This paper shows that BBPD does not lower all prices in the second
period and does not increase consumer surplus
Complementary Data as Metadata: Building Context for the Reuse of Video Records of Practice
Data reuse is often dependent on context external to the data. At times, this context is actually additional data that helps data reusers better assess and/or understand the target data upon which they are focused. We refer to these data as complementary data and define these as data external to the target data which could be used as evidence in their own right. In this paper, we specifically we focus on video records of practice in education. Records of practice are a type of data that more broadly document events surrounding teaching and learning. Video records of practice are an interesting case of data reuse as they can be extensive (e.g., days or weeks of video of a classroom), result in large files sizes, and require both metadata and other complementary data in order for reusers to understand the events depicted in the video. Through our mixed methods study, consisting of a survey of data reusers in 4 repositories and 44 in-depth interviews, we identified the types of complementary data that assist reusers of video records of practice for either teaching and/or research. While there were similarities in the types of complementary data identified as important to have when reusing VROP, the rationales and motivations for seeking out particular complementary data differed depending on whether the intended use was for teaching or research. While metadata is an important and valuable means of describing data for reuse, data’s meaning is often constructed through comparison, verification, or elucidation in reference to other data.
 
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