24 research outputs found
Exact Solution of a Linear Wave Equation in Cosmological General Relativity
A linear second order wave equation is presented based on cosmological
general relativity, which is a space-velocity theory of the expanding Universe.
The wave equation is shown to be exactly solvable, based on the Gaussian
hypergeometric function.Comment: 6 page
Einstein's Rocket Ship, the Deflection of Light and the Precession of the Orbital Perihelion
The nature of the principle of equivalence is explored. The light ray travel path in an accelerated reference frame, a rocket ship, is described and the rocket ship model is used to derive the deflection of light by a massive body. By accounting for the effect of the velocity of the accelerated observer relative to an inertial frame, the additional deflection angle is obtained due to the aberration of the light beam. This model is applied to the deflection of light by a central gravitational field, giving the total deflection angle in agreement with the standard result. Also, a novel approach is given by considering the deflection of light by a massive body to obtain the precession of the perihelion of a planet
On the anomalous acceleration of Pioneer spacecraft
The anomalous acceleration of Pioneer 10 and 11 spacecraft of (8.74 \pm 1.33)
\times 10^{-8} cm. s^{-2} fits with a theoretical prediction of a minimal
acceleration in nature of about 7.61 \times 10^{-8} cm. s^{-2}Comment: 3 pages, accepted in Int. J. Theor. Phy
The Cosmic Time in Terms of the Redshift
In cosmology one labels the time t since the Big Bang in terms of the
redshift of light emitted at t, as we see it now. In this Note we derive a
formula that relates t to z which is valid for all redshifts. One can go back
in time as far as one wishes, but not to the Big Bang at which the redshift
tends to infinity.Comment: 3 pages, 3 figure
Particle Pair Production in Cosmological General Relativity
The Cosmological General Relativity (CGR) of Carmeli, a 5-dimensional (5-D)
theory of time, space and velocity, predicts the existence of an acceleration
a_0 = c / tau due to the expansion of the universe, where c is the speed of
light in vacuum, tau = 1 / h is the Hubble-Carmeli time constant, where h is
the Hubble constant at zero distance and no gravity.
The Carmeli force on a particle of mass m is F_c = m a_0, a fifth force in
nature.
In CGR, the effective mass density rho_eff = rho - rho_c, where rho is the
matter density and rho_c is the critical mass density which we identify with
the vacuum mass density rho_vac = -rho_c.
The fields resulting from the weak field solution of the Einstein field
equations in 5-D CGR and the Carmeli force are used to hypothesize the
production of a pair of particles.
The mass of each particle is found to be m = tau c^3 / 4 G, where G is
Newton's constant.
The vacuum mass density derived from the physics is rho_vac = -rho_c = -3 /
(8 pi G tau^2).
The cosmic microwave background (CMB) black body radiation at the temperature
T_o = 2.72548 K which fills that volume is found to have a relationship to the
ionization energy of the Hydrogen atom. Define the radiation energy
epsilon_gamma = (1 - g) m c^2 / N_gamma, where (1-g) is the fraction of the
initial energy m c^2 which converts to photons, g is a function of the baryon
density parameter Omega_b and N_gamma is the total number of photons in the CMB
radiation field. We make the connection with the ionization energy of the first
quantum level of the Hydrogen atom by the hypothesis epsilon_gamma = [(1 - g) m
c^2] / N_gamma = alpha^2 mu c^2 / 2, where alpha is the fine-structure constant
and mu = m_p f / (1 + f), where f= m_e / m_p with m_e the electron mass and m_p
the proton mass.Comment: 14 pages, 0 figures. The final publication is available at
springerlink.co
Testing Cosmological General Relativity against high redshift observations
Several key relations are derived for Cosmological General Relativity which
are used in standard observational cosmology. These include the luminosity
distance, angular size, surface brightness and matter density. These relations
are used to fit type Ia supernova (SNe Ia) data, giving consistent, well
behaved fits over a broad range of redshift . The best fit to the
data for the local density parameter is .
Because is within the baryonic budget there is no need for any
dark matter to account for the SNe Ia redshift luminosity data. From this local
density it is determined that the redshift where the universe expansion
transitions from deceleration to acceleration is . Because the fitted data covers the range of the
predicted transition redshift , there is no need for any dark energy to
account for the expansion rate transition. We conclude that the expansion is
now accelerating and that the transition from a closed to an open universe
occurred about ago.Comment: Rewritten, improved and revised the discussion. This is now a
combined paper of the former version and the Addendu
The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance
INTRODUCTION
Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic.
RATIONALE
We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs).
RESULTS
Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants.
CONCLUSION
Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century