60 research outputs found
MODELLING-MEASUREMENT-IDENTIFICATION AND THEIR IMPORTANCE IN CONTROLLING WATER SUPPLY SYSTEMS
In case of the revision of a settlement's water distribution system, different models of the
whole system must be developed. In course of modelling we certainly make some approximations,
thus there are certain differences between model and reality. Consequently, it
must be determined, to what degree the model conforms to reality. To prove the conformity
of the model to reality, measurements and calculations of the hydraulic parameters
must be done for some operation conditions, and the results must be compared. We have
made measurements and identifications in Bratislava and in several regions of Hungary,
one of them, the basic zone of Miskolc city is presented. On the basis of comparison of the
calculated and measured values, the identification can be considered as completed (Fig.
4.), the values entirely conform to each other
Methylation of chloroplast DNA does not affect viability and maternal inheritance in tobacco and may provide a strategy towards transgene containment
We report the integration of a type II restriction-methylase, mFokI, into the tobacco chloroplast genome and we demonstrate that the introduced enzyme effectively directs the methylation of its target sequence in vivo and does not affect maternal inheritance. We further report the transformation of tobacco with an E. coli dcm methylase targeted to plastids and we demonstrate efficient cytosine methylation of the plastid genome. Both adenosine methylation of FokI sites and cytosine methylation of dcm sites appeared phenotypically neutral. The ability to tolerate such plastid genome methylation is a pre-requisite for a proposed plant transgene containment system. In such a system, a chloroplast located, maternally inherited restriction methylase would provide protection from a nuclear-encoded, plastid targeted restriction endonuclease. As plastids are not paternally inherited in most crop species, pollen from such plants would carry the endonuclease transgene but not the corresponding methylase; the consequence of this should be containment of all nuclear transgenes, as pollination will only be viable in crosses to the appropriate transplastomic maternal background
Image-based Classification of Variable Stars: First Results from Optical Gravitational Lensing Experiment Data
Recently, machine learning methods presented a viable solution for automated
classification of image-based data in various research fields and business
applications. Scientists require a fast and reliable solution to be able to
handle the always growing enormous amount of data in astronomy. However, so far
astronomers have been mainly classifying variable star light curves based on
various pre-computed statistics and light curve parameters. In this work we use
an image-based Convolutional Neural Network to classify the different types of
variable stars. We used images of phase-folded light curves from the OGLE-III
survey for training, validating and testing and used OGLE-IV survey as an
independent data set for testing. After the training phase, our neural network
was able to classify the different types between 80 and 99%, and 77-98%
accuracy for OGLE-III and OGLE-IV, respectively.Comment: Accepted in ApJL, 11pages, 5 figures, 8 table
Single acute stress-induced progesterone and ovariectomy alter cardiomyocyte contractile function in female rats
Aim To assess how ovarian-derived sex hormones (in particular
progesterone) modify the effects of single acute
stress on the mechanical and biochemical properties of
left ventricular cardiomyocytes in the rat.
Methods Non-ovariectomized (control, n = 8) and ovariectomized
(OVX, n = 8) female rats were kept under normal
conditions or were exposed to stress (control-S, n = 8
and OVX-S, n = 8). Serum progesterone levels were measured
using a chemiluminescent immunoassay. Left ventricular
myocardial samples were used for isometric force
measurements and protein analysis. Ca2+-dependent active
force (Factive), Ca2+-independent passive force (Fpassive),
and Ca2+-sensitivity of force production were determined
in single, mechanically isolated, permeabilized cardiomyocytes.
Stress- and ovariectomy-induced alterations in myofilament
proteins (myosin-binding protein C [MyBP-C], troponin
I [TnI], and titin) were analyzed by sodium dodecyl
sulfate gel electrophoresis using protein and phosphoprotein
stainings. Results Serum progesterone levels were significantly increased
in stressed rats (control-S, 35.6 ± 4.8 ng/mL and
OVX-S, 21.9 ± 4.0 ng/mL) compared to control (10 ± 2.9
ng/mL) and OVX (2.8 ± 0.5 ng/mL) groups. Factive was higher
in the OVX groups (OVX, 25.9 ± 3.4 kN/m2 and OVX-S,
26.3 ± 3.0 kN/m2) than in control groups (control, 16.4 ± 1.2
kN/m2 and control-S, 14.4 ± 0.9 kN/m2). Regarding the
potential molecular mechanisms, Factive correlated with
MyBP-C phosphorylation, while myofilament Ca2+-sensitivity
inversely correlated with serum progesterone levels
when the mean values were plotted for all animal groups.
Fpassive was unaffected by any treatment.
Conclusion Stress increases ovary-independent synthesis
and release of progesterone, which may regulate Ca2+-sensitivity
of force production in left ventricular cardiomyocytes.
Stress and female hormones differently alter Ca2+-
dependent cardiomyocyte contractile force production,
which may have pathophysiological importance during
stress conditions affecting postmenopausal women
The Weakening Outburst of the Young Eruptive Star V582 Aur
V582 Aur is a pre-main sequence FU Orionis type eruptive star, which entered
a brightness minimum in 2016 March due to changes in the line-of-sight
extinction. Here, we present and analyze new optical , , and
band multiepoch observations and new near-infrared , and band
photometric measurements from 2018 January2019 February, as well as publicly
available mid-infrared WISE data. We found that the source shows a significant
opticalnear-infrared variability, and the current brightness minimum has not
completely finished yet. If the present dimming originates from the same
orbiting dust clump that caused a similar brightness variation in 2012, than
our results suggest a viscous spreading of the dust particles along the orbit.
Another scenario is that the current minimum is caused by a dust structure,
that is entering and leaving the inner part of the system. The WISE
measurements could be consistent with this scenario. Our long-term data, as
well as an accretion disk modeling hint at a general fading of V582 Aur,
suggesting that the source will reach the quiescent level in 80 years.Comment: 8 pages, 4 figures, accepted for publication in Ap
Photometric and Spectroscopic Properties of Type Ia Supernova 2018oh with Early Excess Emission from the Kepler 2 Observations
Supernova (SN) 2018oh (ASASSN-18bt) is the first spectroscopically- confirmed type Ia supernova (SN Ia) observed in the field. The data revealed an excess emission in its early light curve, allowing to place interesting constraints on its progenitor system (Dimitriadis et al. 2018, Shappee et al. 2018b). Here, we present extensive optical, ultraviolet, and near-infrared photometry, as well as dense sampling of optical spectra, for this object. SN 2018oh is relatively normal in its photometric evolution, with a rise time of 18.30.3 days and m0.03 mag, but it seems to have bluer colors. We construct the "uvoir" bolometric light curve having peak luminosity as 1.4910erg s, from which we derive a nickel mass as 0.550.04M by fitting radiation diffusion models powered by centrally located Ni. Note that the moment when nickel-powered luminosity starts to emerge is +3.85 days after the first light in the Kepler data, suggesting other origins of the early-time emission, e.g., mixing of Ni to outer layers of the ejecta or interaction between the ejecta and nearby circumstellar material or a non-degenerate companion star. The spectral evolution of SN 2018oh is similar to that of a normal SN Ia, but is characterized by prominent and persistent carbon absorption features. The C II features can be detected from the early phases to about 3 weeks after the maximum light, representing the latest detection of carbon ever recorded in a SN Ia. This indicates that a considerable amount of unburned carbon exists in the ejecta of SN 2018oh and may mix into deeper layers
K2 Observations of SN 2018oh Reveal a Two-component Rising Light Curve for a Type Ia Supernova
We present an exquisite 30 minute cadence Kepler (K2) light curve of the Type Ia supernova (SN Ia) 2018oh (ASASSN-18bt), starting weeks before explosion, covering the moment of explosion and the subsequent rise, and continuing past peak brightness. These data are supplemented by multi- color Panoramic Survey Telescope (Pan-STARRS1) and Rapid Response System 1 and Cerro Tololo Inter-American Observatory 4 m Dark Energy Camera (CTIO 4-m DECam) observations obtained within hours of explosion. The K2 light curve has an unusual two-component shape, where the flux rises with a steep linear gradient for the first few days, followed by a quadratic rise as seen for typical supernovae (SNe) Ia. This “flux excess” relative to canonical SN Ia behavior is confirmed in our i-band light curve, and furthermore, SN 2018oh is especially blue during the early epochs. The flux excess peaks 2.14 ± 0.04 days after explosion, has a FWHM of 3.12 ± 0.04 days, a blackbody temperature of T=17,{500}-9,000+11,500 K, a peak luminosity of 4.3+/- 0.2× {10}37 {erg} {{{s}}}-1, and a total integrated energy of 1.27+/- 0.01× {10}43 {erg}. We compare SN 2018oh to several models that may provide additional heating at early times, including collision with a companion and a shallow concentration of radioactive nickel. While all of these models generally reproduce the early K2 light curve shape, we slightly favor a companion interaction, at a distance of ∼2× {10}12 {cm} based on our early color measurements, although the exact distance depends on the uncertain viewing angle. Additional confirmation of a companion interaction in future modeling and observations of SN 2018oh would provide strong support for a single-degenerate progenitor system
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