282 research outputs found
beta-decay study of Cu-77
A beta-decay study of Cu-77 has been performed at the ISOLDE mass separator
with the aim to deduce its beta-decay properties and to obtain spectroscopic
information on Zn-77. Neutron-rich copper isotopes were produced by means of
proton- or neutron-induced fission reactions on U-238. After the production,
Cu-77 was selectively laser ionized, mass separated and sent to different
detection systems where beta-gamma and beta-n coincidence data were collected.
We report on the deduced half-live, decay scheme, and possible spin assignment
of 77Cu
Changes in the reactivity of the vertebrobasilar arteries when using glucose-electrolyte drink with antioxidant plant extracts during submaximal exercise test
The aim. To assess the effect of glucose-electrolyte composition with plant extracts having antioxidant activity on the hemodynamic parameters of vertebrobasilar system during the incrementally increasing submaximal exercise test.Materials and methods. The study included 12 athletes (6 candidates for master of sports and 6 masters of sports) aged 18–22, who have been engaged in orienteering for 10 years and more. Time of aerobic exercise – 2 hours a day, five days a week. The study subjects performed an incrementally increasing submaximal exercise test and also submaximal exercise test with the preventive intake of a glucose-electrolyte composition with plant extracts having antioxidant properties. To assess the hemodynamic parameters in all study subjects we used Doppler ultrasound of the cerebral vessels, evaluating vertebrobasilar system blood flow, exercise gas test in the modification of hypo- and hyperventilation, and also positional test.Results. A single intake of glucose-electrolyte drink under conditions of incrementally increasing exercise test contributed to the manifestation of a homeostatic effect in hemodynamic parameters of the vertebrobasilar arteries. It is evidenced by the approximation to the pre-exercise level of maximum systolic velocity and average blood velocity in the breath-holding test, of the diastolic blood velocity in the hyperventilation test, and of the pulsatility index in the torsion test, as compared to the isolated submaximal exercise test which caused the change in both velocity indicators and calculated indices during the functional tests.The article considers the main mechanisms underlying the change in arterial hemodynamic parameters caused by incrementally increasing load, as well as describes the proposed mechanisms arising from the combined effect of an incrementally increasing load and the intake of a glucose-electrolyte composition with plant extracts having antioxidant activity.Conclusion. It was shown that using glucose-electrolyte drink contributed to the restoration of hemodynamic parameters of the vertebrobasilar arteries after an incrementally increasing submaximal exercise test
A flare in the optical spotted in the changing-look Seyfert NGC 3516
We present observations from the short-term intensive optical campaign (from
Sep2019 to Jan2020) of the changing-look Seyfert NGC 3516. This active galactic
nucleus is known to have strong optical variability and has changed its type in
the past. It has been in the low-activity state in the optical since 2013, with
some rebrightening from the end of 2015 to the beginning of 2016, after which
it remained dormant. We aim to study the photometric and spectral variability
of NGC 3516 from the new observations in U- and B-bands and examine the
profiles of the optical broad emission lines in order to demonstrate that this
object may be entering a new state of activity. NGC 3516 has been monitored
intensively for the past 4 months with an automated telescope in U and B
filters, enabling accurate photometry of 0.01 precision. Spectral observations
were triggered when an increase in brightness was spotted. We support our
analysis of past-episodes of violent variability with the UV and X-ray
long-term light curves constructed from the archival Swift data. An increase of
the photometric magnitude is seen in both U and B filters to a maximum
amplitude of 0.25mag and 0.1 mag, respectively. During the flare, we observe
stronger forbidden high-ionization iron lines than reported before, as well as
the complex broad Ha and Hb lines. This is especially seen in Ha which appears
to be double-peaked. It seems that a very broad component of ~10,000 km/s in
width in the Balmer lines is appearing. The trends in the optical, UV, and
X-ray light curves are similar, with the amplitudes of variability being
significantly larger in the case of UV and X-ray bands. The increase of the
continuum emission, the variability of the coronal lines, and the very broad
component in the Balmer lines may indicate that the AGN of NGC 3516 is finally
leaving the low-activity state in which it has been for the last ~3 years.Comment: 7 pages, 6 figures, accepted in A&A (corrected after receiving
comments from the language editor
From favorable atomic configurations to supershell structures: a new interpretation of conductance histograms
Title: From favorable atomic configurations to supershell structures: a new
interpretation of conductance histograms Authors: A. Hasmy (IVIC), E. Medina
(IVIC), P.A. Serena (CSIC,IVIC) Comments: 7 pages, 3 figures,
cond-mat.anwar.10825 Subj-class: Soft Condensed MatterComment: 7 pages, 3 figuresSubject: fput HMS.tex HMS-FIG1.ps HMS-FIG2.ps
HMS-FIG3.p
First on-line -NMR on oriented nuclei: magnetic dipole moments of the ground state in Ni and ground state in Cu
The first fully on-line use of the angular distribution of - emission in detection of NMR of nuclei oriented at low temperatures is reported. The magnetic moments of the single valence particle, intermediate mass, isotopes Ni(; 1/2) and Cu(; 3/2) are measured to be +0.601(5) and +2.84(1) respectively, revealing only a small deviation from the neutron single-particle value in the former and a large deviation from the proton single-particle value in the latter. Quantitative interpretation is given in terms of core polarization and meson-exchange currents
Vlasov simulations of electron acceleration by radio frequency heating near the upper hybrid layer
It is shown by using a combination of Vlasov and test particles simulations that the electron distribution function resulting from energization due to Upper Hybrid (UH) plasma turbulence depends critically on the closeness of the pump wave to the double resonance, defined as omega≈omega_UH≈n omega_ce where n is an integer. For pump frequencies, away from the double resonance the electron distribution function is very close to Maxwellian, while as the pump frequency approaches the double resonance it develops a high energy tail. The simulations show turbulence involving coupling between Lower Hybrid (LH) and UH waves, followed by excitation of Electron Bernstein (EB) modes. For the particular case of a pump with frequency between n=3 and n=4 the EB modes cover the range from the first to the 5th mode. The simulations show that when the injected wave frequency is between the 3rd and 4th electron cyclotron frequency, bulk electron heating occurs due to the interaction between the electrons and large amplitude EB waves, primarily on the first EB branch leading to an essentially thermal distribution. On the other hand, when the frequency is slightly above the 4th electron cyclotron harmonic, the resonant interaction is predominantly due to the UH branch and leads to a further acceleration of high-velocity electrons and a distribution function with a suprathermal tail of energetic electrons. The results are consistent with ionospheric experiments and relevant to the production of Artificial Ionospheric Plasma Layers
Advanced optical imaging in living embryos
Developmental biology investigations have evolved from static studies of embryo anatomy and into dynamic studies of the genetic and cellular mechanisms responsible for shaping the embryo anatomy. With the advancement of fluorescent protein fusions, the ability to visualize and comprehend how thousands to millions of cells interact with one another to form tissues and organs in three dimensions (xyz) over time (t) is just beginning to be realized and exploited. In this review, we explore recent advances utilizing confocal and multi-photon time-lapse microscopy to capture gene expression, cell behavior, and embryo development. From choosing the appropriate fluorophore, to labeling strategy, to experimental set-up, and data pipeline handling, this review covers the various aspects related to acquiring and analyzing multi-dimensional data sets. These innovative techniques in multi-dimensional imaging and analysis can be applied across a number of fields in time and space including protein dynamics to cell biology to morphogenesis
- …