Quantum and Inflationary Cosmology with Higher Derivative Gravity

The subject of this thesis is the description of the Very Early Universe, from the Big Bang to the beginning of the radiation-dominated Friedman-Roberston-Walker era. We examine a pure gravity inflationary model for the Universe which is based on adding ƐR2 term to the usual gravitational Lagrangian ("improved Starobinsky model"). We find the classical inflationary solution essentially independent of initial conditions. The model has only one free parameter, which is bounded from above by observational constraints on scalar and tensorial perturbations and from below by both the need for standard baryogenesis and the need for galaxy formation. This requires 1011GeV &#60; Ɛ-1/2 &#60; 1013GeV. The model is interpreted as a Chaotic Inflationary model, with initial conditions for classical evolution being generated by the quantum fluctuations in metric and curvature in Very Early Universe. We discuss those fluctuations using a particular solution of the Wheeler-De Witt equation and find that the inflationary phase is a highly typical event.</p

Initial conditions for R+εR^2 cosmology

A pure gravity cosmology based on the R+εR^2 Lagrangian is known to exhibit inflation for a wide range of initial conditions. In this paper we use the wave function from quantum cosmology to describe this inflation as a chaotic inflationary phase immediately following the quantum creation of the Universe. We evaluate, compare, and discuss the distributions over initial conditions that are fixed by the two boundary-condition proposals of Hartle and Hawking ("no boundary") and Vilenkin ("tunneling from nothing"). We find that among all classical inflationary trajectories that begin on the classical-quantum boundary, those that lead to an inflation of at least 70 e-foldings make up a fraction of ∼exp(-10^12) in the former case and ∼1-exp(-8×10^10) in the latter. Thus, in the simplest interpretation, the observable Universe would be the outcome of a rare event for the first boundary-condition proposal and a typical event for the second

MAGE-A3/4 and NY-ESO-1 antigens expression in metastatic esophageal squamous cell carcinoma

In the present study we analyzed immunohistochemical expression of MAGE-A 3/4 and NY-ESO-1 in 55 samples of esophageal squamous cell carcinomas (ESCC) and their respective lymph node metastases. To our knowledge this is the first study to assess and compare the expression of these antigens in ESCC lymph node metastases

Hemijski sastav lišća i stabljika divergentnih sorti lucerke

Alfalfa is a perennial crop that provides a higher yield of proteins per unit area than any field crop, which makes it highly desirable for the production of hay and feed for domestic animals (especially ruminants). The objective of this study was to determine the dry matter chemical composition in the whole plant, leaves and stems of five divergent alfalfa cultivars. Variations were found in the contents of proteins, hemicellulose, NDF, ADF, ADL, cellulose, and minerals depending on genotype and plant part. Significant differences existed between the cultivars in quality parameters, indicating that breeding for high alfalfa quality is justifiable.Lucerka je višegodišnja vrsta koja daje veći prinos proteina po jedinici površine od bilo koje ratarske kulture, pa je zbog toga veoma poželjna za proizvodnju sena i u ishrani domaćih životinja (posebno preživara). Cilj rada je bio da se odredi hemijski sastav suve materije lucerke kod pet divergentenih sorti lucerke u celoj biljci kao i u listu i stabljikama. Lucerka varira u sadržaju proteina, celuloze, hemiceluloze, NDF, ADF, ADL, i mineralnih materija u zavisnosti od genotipa i biljnog dela. Postoje značajne razlike u komponentama hranljive vrednosti lucerke između sorti što ukazuje da oplemenjivanje na veći kvalitet lucerke ima smisla

Hamiltonian analysis of Poincar\'e gauge theory scalar modes

The Hamiltonian constraint formalism is used to obtain the first explicit complete analysis of non-trivial viable dynamic modes for the Poincar\'e gauge theory of gravity. Two modes with propagating spin-zero torsion are analyzed. The explicit form of the Hamiltonian is presented. All constraints are obtained and classified. The Lagrange multipliers are derived. It is shown that a massive spin-$0^-$ mode has normal dynamical propagation but the associated massless $0^-$ is pure gauge. The spin-$0^+$ mode investigated here is also viable in general. Both modes exhibit a simple type of ``constraint bifurcation'' for certain special field/parameter values.Comment: 28 pages, LaTex, submitted to International Journal of Modern Physics

Almost-homogeneity of the universe in higher-order gravity

In the $R+\alpha R^2$ gravity theory, we show that if freely propagating massless particles have an almost isotropic distribution, then the spacetime is almost Friedmann-Robertson-Walker (FRW). This extends the result proved recently in general relativity ($\alpha=0$), which is applicable to the microwave background after photon decoupling. The higher-order result is in principle applicable to a massless species that decouples in the early universe, such as a relic graviton background. Any future observations that show small anisotropies in such a background would imply that the geometry of the early universe were almost FRW.Comment: 14 pages LaTeX, no figures; to appear in General Relativity and Gravitatio

Pleural empyema as a complication of COVID 19 pneumonia in a patient with destroyed lung syndrome

Introduction. Destroyed lung syndrome is a severe destruction of the pleural parenchyma due to lung infection, mostly caused by tuberculosis. Besides tuberculosis, necrotizing pneumonia may also lead to this disease complication. Pleural empyema is a frequent consequence of the destroyed lung syndrome. Pleural empyema may occur during the COVID-19 infection and is negatively correlated with a favorable disease outcome. Case report. A male 50 y/o showed up during the on-call shift during the winter COVID-19 wave with a medical report from the Internal medicine clinic. His personal history is significant for his pneumonectomy in 2016. In the past two months, he had been treated for pneumonia and COVID-19 infection with antibiotics and corticosteroid therapy. Due to prolonged malaise and tachycardia his GP referred him to yet another chest X-ray and lab work. The chest X-ray showed pleural effusion, so he was promptly referred to an on-call hospital. The on-call physician, after looking into the hospital reports, consulted an internal medicine doctor and it was decided to refer the patient to a thoracic surgeon. He was hospitalized for pleural empyema and treated with thoracic drainage using the system of active aspiration. A year later, he feels well, and he regained his appetite, and body mass, with occasional leaking from the thoracic fistule. Conclusion. This case report shows a recurrence of pleural empyema in a patient with pneumonectomy due to necrotizing pneumonia and destroyed lung syndrome, complicated by COVID-19 infection. We aimed to draw the attention of GPs to diseases and disease complications that are rarely met in GP practice and are not otherwise treated on the primary healthcare level

Cascade Birth of Universes in Multidimensional Spaces

The formation mechanism of universes with distinctly different properties is considered within the framework of pure gravity in a space of D > 4 dimensions. The emergence of the Planck scale and its relationship to the inflaton mass are discussed.Comment: 10 p., minor correction

Space for Both No-Boundary and Tunneling Quantum States of the Universe

At the minisuperspace level of homogeneous models, the bare probability for a classical universe has a huge peak at small universes for the Hartle-Hawking `no-boundary' wavefunction, in contrast to the suppression at small universes for the `tunneling' wavefunction. If the probability distribution is cut off at the Planck density (say), this suggests that the former quantum state is inconsistent with our observations. For inhomogeneous models in which stochastic inflation can occur, it is known that the idea of including a volume factor in the observational probability distribution can lead to arbitrarily large universes' being likely. Here this idea is shown to be sufficient to save the Hartle-Hawking proposal even at the minisuperspace level (for suitable inflaton potentials), by giving it enough space to be consistent with observations.Comment: LaTeX, 20 pages, no figures, blank lines removed, page break inserte