1,432 research outputs found

    JWST early Universe observations and {\Lambda}CDM cosmology

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    Deep space observations of the James Webb Space Telescope (JWST) have revealed that the structure and masses of very early Universe galaxies at high redshifts (z~15), existing at ~0.3 Gyr after the BigBang, maybe as evolved as the galaxies in existence for ~10 Gyr. The JWST findings are thus in strong tension with the Λ{\Lambda}CDM cosmological model. While tired light (TL) models have been shown to comply with the JWST angular galaxy size data, they cannot satisfactorily explain isotropy of the cosmic microwave background (CMB) observations or fit the supernovae distance modulus vs. redshift data well. We have developed hybrid models that include the tired light concept in the expanding universe. The hybrid Λ{\Lambda}CDM model fits the supernovae type 1a data well but not the JWST observations. We present a model with covarying coupling constants (CCC), starting from the modified FLRW metric and resulting Einstein and Friedmann equations, and a CCC+TL hybrid model. They fit the Pantheon+ data admirably, and the CCC+TL model is compliant with the JWST observations. It stretches the age of the universe to 26.7 Gyr with 5.8 Gyr at z=10 and 3.5 Gyr at z=20, giving enough time to form massive galaxies. It thus resolves the 'impossible early galaxy' problem without requiring the existence of primordial black hole seeds or modified power spectrum, rapid formation of massive population III stars, and super Eddington accretion rates. One could infer the CCC model as an extension of the Λ{\Lambda}CDM model with a dynamic cosmological constant.Comment: 16 pages, 7 figures. Published in MNRAS 524, 3385-3395 (2023

    Measuring inertial mass with Kibble balance

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    A Kibble balance measures the gravitationalgravitational mass (weight) of a test mass with extreme precision by balancing the gravitational pull on the test mass against the electromagnetic lift force. The uncertainty in such mass measurement is currently ~1×1081\times 10^{-8} . We show how the same Kibble balance can be used to measure the inertialinertial mass of a test mass, that too with potentially 50% better measurement uncertainty, i.e., ~5×1095\times 10^{-9} . For measuring the inertial mass, the weight of the test mass and the assembly holding it is precisely balanced by a counterweight. The application of the known electromagnetic force accelerates the test mass. Measuring the velocity after a controlled elapsed time provides the acceleration and consequently the inertial mass of the accelerated assembly comprising the Kibble balance coil and the mass holding pan. Repeating the measurement with the test mass added to the assembly and taking the difference between the two measurements yields the inertial mass of the test mass. Thus, the extreme precision inertial and gravitational mass measurement of a test mass with a Kibble balance could provide a test of the equivalence principle. We discuss how the two masses are related to the Planck constant and other coupling constants and how the Kibble balance could be used to test the dynamic constants theories in Dirac cosmology.Comment: 6 pages, 1 figure. Corrections and additions. Prepared for readers' comments before submitting to a journa

    Varying Coupling Constants and Their Interdependence

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    Since Dirac predicted in 1937 possible variation of gravitational constant and other coupling constants from his large number hypothesis, efforts continue to determine such variation without success. Such efforts focus on the variation of one constant while assuming all others pegged to their currently measured values. We show that the variations of the speed of light cc, the gravitational constant GG, the Planck constant hh, and the Boltzmann constant kk are interrelated: Gc3h3k3/2G\thicksim c^{3}\thicksim h^{3}\thicksim k^{3/2}. Thus, constraining any one of the constants leads to inadvertently constraining all the others. It may not be possible to determine the variation of a constant without concurrently considering the variation of others. We discuss several astrophysical observations that have been explained recently with the concomitant variation of two or more constants. We also analyze the reported and unexplained 35 micro-gram decrease of 1 Kg Pt-Ir working standards over 22 years of measurements and show that they can be accounted for by allowing GG, cc, and hh to vary as predicted, provided such mass decrease can be confirmed with a Kibble balance used for determining the Planck constant and weighing test-masses with extreme precision.Comment: 6 pages. This version has been accepted by Mod. Phys. Lett.

    How might India's public health systems be strengthened ?

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    The central government’s policies, though well-intentioned, have inadvertently de-emphasized environmental health and other preventive public health services in India since the 1950s, when it was decided to amalgamate the medical and public health services and to focus public health services largely on single-issue programs. This paper discusses how successive policy decisions have diminished the Health Ministry’s capacity for stewardship of the nation’s public health. These decisions have introduced policies and fiscal incentives that have inadvertently enabled states to prioritize medical services and single-issue programs over broader public health services, and diminished the capacity of the public health workforce to deliver public health services. Diseases resulting from poor environmental health conditions continue to impose high costs even among the more affluent, and hinder development. There are many approaches to strengthening the public health system, and the authors suggest one that may require relatively little modification of existing structures and systems. They suggest establishing a focal point in the Health Ministry for public health stewardship, and re-vitalizing the states’ public health managerial cadres as well as the grassroots public health workers. The central government could consider linking its fiscal support to states with phased progress in four areas: (1) the enactment of state Public Health Acts; (2) the establishment by states of separate public health directorates; (3) the re-vitalization of grassroots public health workers; and (4) health department engagement in ensuring municipal public health. The central focal point could provide the needed support, oversight, incentives, and sanctions to ensure that states build robust public health systems. These measures can do much to help governments use public funds more effectively for protecting people’s health.Health Monitoring&Evaluation,Health Systems Development&Reform,Population Policies,Disease Control&Prevention,Health Economics&Finance
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