In this paper we consider the correspondence between the tachyon dark energy model and the Tsallis holographic dark energy scenario in an FRW universe. We demonstrate the Tsallis holographic description of tachyon dark energy in an FRW universe and reconstruct the potential and basic results of the ...
More
In this paper we consider the correspondence between the tachyon dark energy model and the Tsallis holographic dark energy scenario in an FRW universe. We demonstrate the Tsallis holographic description of tachyon dark energy in an FRW universe and reconstruct the potential and basic results of the dynamics of the scalar field which describe the tachyon cosmology. In a flat universe, in the tachyon model of Tsallis holographic dark energy, independently of the existence of interaction between dark energy and matter or not, T˙ 2 must always be zero. Therefore, the equation of state ωD is always −1 in such a flat universe. For a non-flat universe, T˙ 2 cannot be zero so that ωD 6= −1 which cannot be used to explain the origin of the cosmological constant. T˙ 2 monotonically decreases with the increasing of cos(Rh/a) and cosh(Rh/a) for different δs. In particular, for an open universe, T˙ 2 is always larger than zero while for a closed universe, T˙ 2 is always smaller than zero which is physically invalid. In addition, we conclude that with the increasing of cos(Rh/a) and cosh(Rh/a), T˙ 2 always decreases monotonically for irrespective of the value of b2.
Less
Posted 2 years ago
Anand K. Bhatia
Anand K. Bhatia
Institution: Heliophysics Science Division, NASA/Goddard Space Flight Center,
Email: d.k.bhatia@nasa.gov
The excitation cross-sections of the nS states of atomic hydrogen, n = 2 to 6, by electron
impact on the ground state of atomic hydrogen were calculated using the variational polarizedorbital method at various incident electron energies in the range 10 to 122 eV. Converged excitation
cross-sectio...
More
The excitation cross-sections of the nS states of atomic hydrogen, n = 2 to 6, by electron
impact on the ground state of atomic hydrogen were calculated using the variational polarizedorbital method at various incident electron energies in the range 10 to 122 eV. Converged excitation
cross-sections were obtained using sixteen partial waves (L = 0 to 15). Excitation cross-sections to
2S state, calculated earlier, were calculated at higher energies than before. Results obtained using
the hybrid theory (variational polarized orbital method) are compared to those obtained using other
approaches such as the Born–Oppenheimer, close-coupling, R-matrix, and complex-exterior scaling
methods using only the spherical symmetric wave functions. Phase shifts and elastic cross-sections
are given at various energies and angular momenta. Excitation rate coefficients were calculated at
various electron temperatures, which are required for plasma diagnostics in solar and astrophysics to
infer plasma parameters. Excitation cross-sections are compared with those obtained by positron
impact excitation.
Less
Posted 2 years ago
Genki Shibukawa
Genki Shibukawa
Institution: University
Email: info@res00.com
We present an explicit formula of the powers for the 2×2 quantum matrices, that is a natural quantum analogue of the powers of the
usual 2 × 2 matrices. As applications, we give some non-commutative relations of the entries of the powers for the 2 × 2 quantum matrices, which is a simple proof of...
More
We present an explicit formula of the powers for the 2×2 quantum matrices, that is a natural quantum analogue of the powers of the
usual 2 × 2 matrices. As applications, we give some non-commutative relations of the entries of the powers for the 2 × 2 quantum matrices, which is a simple proof of the results of Vokos-Zumino-Wess (1990).
Less
Posted 2 years ago
Muhamed Amin
Muhamed Amin
Institution: Department of Sciences, University College Groningen, University of Groningen, Hoendiepskade
Email: m.a.a.amin@rug.nl
Serial Femtosecond Crystallography at the X-ray Free Electron Laser (XFEL) sources enabled the imaging
of the catalytic intermediates of the oxygen evolution reaction of Photosystem II. However, due to the
incoherent transition of the S-states, the resolved structures are a convolution from diff...
More
Serial Femtosecond Crystallography at the X-ray Free Electron Laser (XFEL) sources enabled the imaging
of the catalytic intermediates of the oxygen evolution reaction of Photosystem II. However, due to the
incoherent transition of the S-states, the resolved structures are a convolution from different catalytic states.
Here, we train Decision Tree Classifier and K-mean clustering models on Mn compounds obtained from
the Cambridge Crystallographic Database to predict the S-state of the X-ray, XFEL, and CryoEm structures
by predicting the Mn's oxidation states in the oxygen evolving complex (OEC). The model agrees mostly
with the XFEL structures in the dark S1 state. However, significant discrepancies are observed for the
excited XFEL states (S2, S3, and S0) and the dark states of the X-ray and CryoEm structures. Furthermore,
there is a mismatch between the predicted S-states within the two monomers of the same dimer, mainly in
the excited states. The model suggests that improving the resolution is crucial to precisely resolve the
geometry of the illuminated S-states to overcome the noncoherent S-state transition. In addition, significant
radiation damage is observed in X-ray and CryoEM structures, particularly at the dangler Mn center (Mn4).
Our model represents a valuable tool for investigating the electronic structure of the catalytic metal cluster
of PSII to understand the water splitting mechanism.
Less
Posted 2 years ago
In the article, the fireball formed in the collision of relativistic nuclei is considered as a quantum object. Based on this, an attempt is made to explain the difference in the measurements of hyperon yields in the two experiments - NA49 and NA57. Using the basic principles of quantum mechanics, it...
More
In the article, the fireball formed in the collision of relativistic nuclei is considered as a quantum object. Based on this, an attempt is made to explain the difference in the measurements of hyperon yields in the two experiments - NA49 and NA57. Using the basic principles of quantum mechanics, it was shown that a fireball can have two quantum states - with and without ignited Quark-Gluon Plasma (QGP). With an increase of the collision energy of heavy ions, the probability of QGP ignition increases. At the same time, the probability of the formation of a fireball without igniting the QGP also remains not zero
Less
Posted 2 years ago
Mohammad R. Garousi
Mohammad R. Garousi
Institution: Department of Physics, Faculty of Science, Ferdowsi University of Mashhad,
Email: garousi@um.ac.ir
Recently, using the assumption that the string theory effective action at the critical dimension is background independent, the classical on-shell effective action of the bosonic string theory at order α in a spacetime manifold without boundary has been reproduced, up to an overall parameter, by im...
More
Recently, using the assumption that the string theory effective action at the critical dimension is background independent, the classical on-shell effective action of the bosonic string theory at order α in a spacetime manifold without boundary has been reproduced, up to an overall parameter, by imposing the O(1, 1) symmetry when the background has a circle. In the presence of the boundary, we consider a background which has boundary and a circle such that the unit normal vector of the boundary is independent of the circle. Then the O(1, 1) symmetry can fix the bulk action without using the lowest order equation of motion. Moreover, the above constraints and the constraint from the principle of the least action in the presence of boundary can fix the boundary action, up to five boundary parameters. In the least action principle, we assume that not only the values
of the massless fields but also the values of their first derivatives are arbitrary on the boundary. We have also observed
that the cosmological reduction of the leading order action in the presence of the Hawking–Gibbons boundary term, produces zero cosmological boundary action. Imposing this as another constraint on the boundary couplings at order α, we find the boundary action up to two parameters. For a specific value for these two parameters, the gravity couplings in the boundary become the Chern–Simons gravity plus another term which has the Laplacian of the extrinsic curvature.
Less
Posted 2 years ago
Vladimir Zaichick
Vladimir Zaichick
Institution: Radionuclide Diagnostics Department, Medical Radiological Research Centre,
Email: vzaichick@gmail.com
Role of chemical elements (ChE) in etiology and pathogenesis of Riedel’s disease (RD) is unclear. The aim of this exploratory study was to assess whether
there were significant changes in thyroid tissue levels of eight ChE (Br, Ca Cl, I, K, Mg, Mn, and Na) are present in the fibrotic transformed...
More
Role of chemical elements (ChE) in etiology and pathogenesis of Riedel’s disease (RD) is unclear. The aim of this exploratory study was to assess whether
there were significant changes in thyroid tissue levels of eight ChE (Br, Ca Cl, I, K, Mg, Mn, and Na) are present in the fibrotic transformed thyroid. Eight
ChE of thyroid tissue were determined in 6 patients with RD. The control group included thyroid tissue samples from 105 healthy individuals. Measurements
were conducted using non-destructive instrumental neutron activation analysis with high-resolution spectrometry of short-lived radionuclides. Reduced
mean values of Ca and I content in 6.3 and 6.7 times, respectively, while elevated level of Br in 5.1 times were found in thyroid with RD in comparison with
normal level. Because considerable changes in some ChE contents in tissue of thyroid with RD were found, it is reasonable to assume that the levels of these
ChE in affected thyroid tissue can be used as RD markers. However, this topic needs additional studies.
Less
Posted 2 years ago
Aamir Jalal Al-Mosawi
Aamir Jalal Al-Mosawi
Institution: Baghdad Medical City and Iraqi Ministry of Health
Email: almosawiAJ@yahoo.com
Background: The year 2020 witnessed the rapid spread of covid-19 pandemic in Iraq and in almost all the countries in the world. This spread has created a serious health crises and a public health emergency in Iraq and throughout the world. Throughout the world, healthcare systems have been negativel...
More
Background: The year 2020 witnessed the rapid spread of covid-19 pandemic in Iraq and in almost all the countries in the world. This spread has created a serious health crises and a public health emergency in Iraq and throughout the world. Throughout the world, healthcare systems have been negatively
influenced by the pandemic and experienced unexpected changes. We have previously provided several descriptions of the Iraq health care system from its evolution. However, little is known about the health care system in Iraq during the first year of the coves pandemic. The aim of this paper is provide a description of the healthcare system in Iraq during the year 2020, the first year of covid-19 global pandemic.
Materials and Methods: The available unpublished and published data about the Iraqi healthcare system during the first year of covid-19 pandemic, the
year 2020 were examined. The data included more than 100 relevant unpublished and published information documents including journal articles, books, official reports of the Iraqi Ministry of Planning and Iraqi Ministry of Health. In addition, relevant useful data available at internet web sites were also
reviewed. The available relevant data were classified into categories including; demographic data relevant to healthcare, Data related to covid-19 disease in Iraq, data related to the organizational structure of the healthcare system, data related to national healthcare policies including national healthcare mission, vision, strategic goals and plans, data related to healthcare system financing, data about healthcare services delivery, data about the workforce in the Iraq
healthcare system, data related to child health and maternal, data about notifiable infectious disease, data about chronic disorders and the main causes of morbidity and mortality, and data about medical education and healthcare education. Many relevant healthcare data for three provinces (The Kurdish provinces in the north of Iraq) of the eighteen provinces in Iraq were not available in English or Arabic.
Results: The population of Iraq in 2020 was estimated at 40.150.174 (20.284.823 males and 19.865.351 females). During the year 2020, 595291 cases of
covid-19 disease were registered by the Iraqi Ministry of Health. 12813 (2.15%) patients died and 537841 (90.3%) patients experienced recovery. The organizational structure of the Iraq health system, the backbone of the Iraq healthcare system witnessed no important change from the description before
covid-19 global pandemic in 2019.
The declared mission and vision of the Iraqi Ministry of Health for the year 2020 were the same mission and vision of the Iraqi Ministry of Health that were declared in 2018. In 2020, the Iraqi Ministry of Health declared a strategic plan which included a vision and mission statements for the health information system. The first year of covid-19 pandemic in Iraq was not associated with an important increase in the number of primary healthcare centers. However, there was little increase in the number of governmental hospitals. Surprisingly, the bed occupancy rate of governmental hospitals during the first year of the
pandemic was lower than the bed occupancy rate during the two years before the pandemic. The total number of hospitalized patients in 2020 was lower than the previous four years, but the mortality rate per 1000 hospitalized patients was significantly higher in 2020 than the previous four years.
Conclusion: Covid-19 disease in Iraq was associated with a significant mortality during the year 2020. It actually changed the previously reported national mortality pattern as covid-19 has become the second most common cause of death in Iraq. Contradictory, to the general belief that mortality associated with covid-19 disease was generally restricted to the older age groups, 117 children under the age of ten years died because of covid-19 disease in 2020. This number of childhood deaths suggests the need to consider vaccination of the younger age groups and to perform the relevant research. Covid-19 disease has emerged as a new notifiable infectious disease in Iraq and throughout the world; therefore, it changed the pattern of notifiable infectious diseases in Iraq.
Less
Posted 2 years ago
Arpita Biswas
Arpita Biswas
Institution: Department of Chemistry, Shibpur Dinobundhoo Institution (College),
Email: abiswas83@gmail.com
Synthesis of Zincoxide nanoparticles (ZnO NPs) with definite size and shape and their
morphological characterization rationally is really a challenging aspect at present due to the ongoing
demand of these nanosize particles for their divergent use in different field of science and technology.
...
More
Synthesis of Zincoxide nanoparticles (ZnO NPs) with definite size and shape and their
morphological characterization rationally is really a challenging aspect at present due to the ongoing
demand of these nanosize particles for their divergent use in different field of science and technology.
Reduction of Zinc acetate dihydrate by sodium hydroxide was performed to produce ZnO NPs by
following precipitation method. Here the whole reaction was completed in aqueous medium in low
temperature. To characterize the synthesized ZnO NPs some recent techniques like X-ray diffraction
study (XRD), Ultra-violet Visible (UV-Vis) spectroscopy, Field emission scanning electron microscopy
(FESEM), Transmission electron microscopy (TEM), Selected area electron diffraction (SAED) and
Electron diffraction X-ray (EDX) were used systematically.
Less
Posted 2 years ago
The relative velocity between objects with finite velocity affects the reaction
between them. This effect is known as general Doppler effect. The Laser Interferometer
Gravitational-Wave Observatory (LIGO) discovered gravitational waves and found their
speed to be equal to the speed of light c. Gr...
More
The relative velocity between objects with finite velocity affects the reaction
between them. This effect is known as general Doppler effect. The Laser Interferometer
Gravitational-Wave Observatory (LIGO) discovered gravitational waves and found their
speed to be equal to the speed of light c. Gravitational waves are generated following
a disturbance in the gravitational field; they affect the gravitational force on an object.
Just as light waves are subject to the Doppler effect, so are gravitational waves. This
article explores the following research questions concerning gravitational waves: Is there
a linear relationship between gravity and velocity? Can the speed of a gravitational wave
represent the speed of the gravitational field (the speed of the action of the gravitational
field upon the object)? What is the speed of the gravitational field? What is the spatial
distribution of gravitational waves? Do gravitational waves caused by the revolution of
the Sun affect planetary precession? Can we modify Newton’s gravitational equation
through the influence of gravitational waves?
Less
Posted 2 years ago