3,258 research outputs found
Ion beam effect on Ge-Se chalcogenide glass films: Non-volatile memory array formation, structural changes and device performance
The conductive bridge non-volatile memory technology is an emerging way to
replace traditional charge based memory devices for future neural networks and
configurable logic applications. An array of the memory devices that fulfills
logic operations must be developed for implementing such architectures. A
scheme to fabricate these arrays, using ion bombardment through a mask, has
been suggested and advanced by us. Performance of the memory devices is
studied, based on the formation of vias and damage accumulation due to the
interactions of Ar+ ions with GexSe1-x (x=0.2, 0.3 and 0.4) chalcogenide
glasses as a function of the ion energy and dose dependence. Blanket films and
devices were created to study the structural changes, surface roughness, and
device performance. Raman Spectroscopy, Atomic Force Microscopy (AFM), Energy
Dispersive X-Ray Spectroscopy (EDS) and electrical measurements expound the Ar+
ions behavior on thin films of GexSe1-x system. Raman studies show that there
is a decrease in area ratio between edge-shared to corner-shared structural
units, revealing occurrence of structural reorganization within the system as a
result of ion/film interaction. AFM results demonstrate a tendency in surface
roughness improvement with increased Ge concentration, after ion bombardment.
EDS results reveal a compositional change in the vias, with a clear tendency of
greater interaction between ions and the Ge atoms, as evidenced by greater
compositional changes in the Ge rich films
Building a Sentiment Corpus of Tweets in Brazilian Portuguese
The large amount of data available in social media, forums and websites
motivates researches in several areas of Natural Language Processing, such as
sentiment analysis. The popularity of the area due to its subjective and
semantic characteristics motivates research on novel methods and approaches for
classification. Hence, there is a high demand for datasets on different domains
and different languages. This paper introduces TweetSentBR, a sentiment corpora
for Brazilian Portuguese manually annotated with 15.000 sentences on TV show
domain. The sentences were labeled in three classes (positive, neutral and
negative) by seven annotators, following literature guidelines for ensuring
reliability on the annotation. We also ran baseline experiments on polarity
classification using three machine learning methods, reaching 80.99% on
F-Measure and 82.06% on accuracy in binary classification, and 59.85% F-Measure
and 64.62% on accuracy on three point classification.Comment: Accepted for publication in 11th International Conference on Language
Resources and Evaluation (LREC 2018
E-creativity: investigating computer-supported creativity
A fusion of the power of modem information and communication technology with the potential of human creativity provides an important and interesting area for research. In this paper, we outline this general research area that we term ecreativity. In particular, we describe our own focus of interest that we label computer supported creativity and the design of creativity support systems. As this is a largely uncharted territory, further research is of vital importance. We describe our research approach in this area and illustrate this with extracts from a case study of an artist who makes extensive and novel use of information technology in her creation of paintings.<br /
Galaxy bimodality versus stellar mass and environment
We analyse a z<0.1 galaxy sample from the Sloan Digital Sky Survey focusing
on the variation of the galaxy colour bimodality with stellar mass and
projected neighbour density Sigma, and on measurements of the galaxy stellar
mass functions. The characteristic mass increases with environmental density
from about 10^10.6 Msun to 10^10.9 Msun (Kroupa IMF, H_0=70) for Sigma in the
range 0.1--10 per Mpc^2. The galaxy population naturally divides into a red and
blue sequence with the locus of the sequences in colour-mass and
colour-concentration index not varying strongly with environment. The fraction
of galaxies on the red sequence is determined in bins of 0.2 in log Sigma and
log mass (12 x 13 bins). The red fraction f_r generally increases continuously
in both Sigma and mass such that there is a unified relation: f_r =
F(Sigma,mass). Two simple functions are proposed which provide good fits to the
data. These data are compared with analogous quantities in semi-analytical
models based on the Millennium N-body simulation: the Bower et al. (2006) and
Croton et al. (2006) models that incorporate AGN feedback. Both models predict
a strong dependence of the red fraction on stellar mass and environment that is
qualitatively similar to the observations. However, a quantitative comparison
shows that the Bower et al. model is a significantly better match; this appears
to be due to the different treatment of feedback in central galaxies.Comment: 19 pages, 17 figures; accepted by MNRAS, minor change
CFHT AO Imaging of the CLASS Gravitational Lens System B1359+154
We present adaptive optics imaging of the CLASS gravitational lens system
B1359+154 obtained with the Canada-France-Hawaii Telescope (CFHT) in the
infrared K band. The observations show at least three brightness peaks within
the ring of lensed images, which we identify as emission from multiple lensing
galaxies. The results confirm the suspected compound nature of the lens, as
deduced from preliminary mass modeling. The detection of several additional
nearby galaxies suggests that B1359+154 is lensed by the compact core of a
small galaxy group. We attempted to produce an updated lens model based on the
CFHT observations and new 5-GHz radio data obtained with the MERLIN array, but
there are too few constraints to construct a realistic model at this time. The
uncertainties inherent with modeling compound lenses make B1359+154 a
challenging target for Hubble constant determination through the measurement of
differential time delays. However, time delays will offer additional
constraints to help pin down the mass model. This lens system therefore
presents a unique opportunity to directly measure the mass distribution of a
galaxy group at intermediate redshift.Comment: 12 pages including 3 figures; ApJL accepte
Development of a RVFV ELISA that can distinguish infected from vaccinated animals
<p>Abstract</p> <p>Background</p> <p>Rift Valley Fever Virus is a pathogen of humans and livestock that causes significant morbidity and mortality throughout Africa and the Middle East. A vaccine that would protect animals from disease would be very beneficial to the human population because prevention of the amplification cycle in livestock would greatly reduce the risk of human infection by preventing livestock epizootics. A mutant virus, constructed through the use of reverse genetics, is protective in laboratory animal models and thus shows promise as a potential vaccine. However, the ability to distinguish infected from vaccinated animals is important for vaccine acceptance by national and international authorities, given regulations restricting movement and export of infected animals.</p> <p>Results</p> <p>In this study, we describe the development of a simple assay that can be used to distinguish naturally infected animals from ones that have been vaccinated with a mutant virus. We describe the cloning, expression and purification of two viral proteins, and the development of side by side ELISAs using the two viral proteins.</p> <p>Conclusion</p> <p>A side by side ELISA can be used to differentiate infected from vaccinated animals. This assay can be done without the use of biocontainment facilities and has potential for use in both human and animal populations.</p
Rift Valley fever virus lacking NSm proteins retains high virulence in vivo and may provide a model of human delayed onset neurologic disease
AbstractRift Valley fever virus is a significant human and veterinary pathogen responsible for explosive outbreaks throughout Africa and the Arabian Peninsula. Severe acute disease in humans includes rapid onset hepatic disease and hemorrhagic fever or delayed onset encephalitis. A highly efficient reverse genetics system was developed which allowed generation of recombinant RVF viruses to assess the role of NSm protein in virulence in a rat model in which wild-type RVF virus strain ZH501 (wt-ZH501) results in 100% lethal hepatic disease 2–3 days post infection. While extensive genomic analysis indicates conservation of the NSm coding capability of diverse RVF viruses, and viruses deficient in NSs proteins are completely attenuated in vivo, comparison of wt-ZH501, a reverse genetics generated wt-ZH501 virus (R-ZH501), and R-ZH501 virus lacking the NSm proteins (R-ΔNSm-ZH501) demonstrated that the NSm proteins were nonessential for in vivo virulence and lethality. Surprisingly, while 44% of R-ΔNSm-ZH501 infected animals quickly developed lethal hepatic disease similar to wt- and R-ZH501, 17% developed delayed onset neurologic disease (lethargy, head tremors, and ataxia) at 13 days post infection. Such infections may provide the basis for study of both RVF acute hepatic disease and delayed onset encephalitic disease in humans
Thottapalayam virus is genetically distant to the rodent-borne hantaviruses, consistent with its isolation from the Asian house shrew (Suncus murinus)
Thottapalayam (TPM) virus belongs to the genus Hantavirus, family Bunyaviridae. The genomes of hantaviruses consist of three negative-stranded RNA segments (S, M and L) encoding the virus nucleocapsid (N), glycoprotein (Gn, Gc), and polymerase (L) proteins, respectively. The genus Hantavirus contains predominantly rodent-borne viruses, with the prominent exception of TPM virus which was isolated in India in 1964 from an insectivore, Suncus murinus, commonly referred to as the Asian house shrew or brown musk shrew. Analysis of the available TPM virus S (1530 nt) RNA genome segment sequence and the newly derived M (3621 nt) and L (6581 nt) segment sequences demonstrate that the entire TPM virus genome is very unique. Remarkably high sequence differences are seen at the nucleotide (up to S – 47%, M – 49%, L – 38%) and protein (up to N – 54%, Gn/Gc – 57% and L – 39%) levels relative to the rodent-borne hantaviruses, consistent with TPM virus having a unique host association
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