Editorial: Impact and control of food- and waterborne protozoan parasites

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A new dynamical model for the study of galactic structure

In the present article, we present a new gravitational galactic model, describing motion in elliptical as well as in disk galaxies, by suitably choosing the dynamical parameters. Moreover, a new dynamical parameter, the S(g) spectrum, is introduced and used, in order to detect islandic motion of resonant orbits and the evolution of the sticky regions. We investigate the regular or chaotic character of motion, with emphasis in the different dynamical models and make an extensive study of the sticky regions of the system. We use the classical method of the Poincare (r-pr) phase plane and the new dynamical parameter of the S(g) spectrum. The LCE is used, in order to make an estimation of the degree of chaos in our galactic model. In both cases, the numerical calculations, suggest that our new model, displays a wide variety of families of regular orbits, compared to other galactic models. In addition to the regular motion, this new model displays also chaotic regions. Furthermore, the extent of the chaotic regions increases, as the value of the flatness parameter b of the model increases. Moreover, our simulations indicate, that the degree of chaos in elliptical galaxies, is much smaller than that in dense disk galaxies. In both cases numerical calculations show, that the degree of chaos increases linearly, as the flatness parameter b increases. In addition, a linear relationship between the critical value of angular momentum and the b parameter if found, in both cases (elliptical and disk galaxies). Some theoretical arguments to support the numerical outcomes are presented. Comparison with earlier work is also made.Comment: Published in New Astronomy journa

Exploring the nature of orbits in a galactic model with a massive nucleus

In the present article, we use an axially symmetric galactic gravitational model with a disk-halo and a spherical nucleus, in order to investigate the transition from regular to chaotic motion for stars moving in the meridian (r,z) plane. We study in detail the transition from regular to chaotic motion, in two different cases: the time independent model and the time evolving model. In the time dependent model, we follow the evolution of orbits as the galaxy develops a dense and massive nucleus in its core, as mass is transported exponentially from the disk to the galactic center. In addition, we construct some numerical diagrams in which we present the correlations between the main parameters of our galactic model. Our numerical calculations indicate, that stars with values of angular momentum Lz less than or equal to a critical value Lzc, moving near to the galactic plane, are scattered to the halo upon encountering the nuclear region and subsequently display chaotic motion. A linear relationship exists between the critical value of the angular momentum Lzc and the mass of the nucleus Mn. Furthermore, the extent of the chaotic region increases as the value of the mass of the nucleus increases. Moreover, our simulations indicate that the degree of chaos increases linearly, as the mass of the nucleus increases. These results strongly indicate that the ordered or chaotic nature of orbits, depends on the presence of massive objects in the galactic cores of the galaxies. Our results suggest, that for disk galaxies with massive and prominent nuclei, the low angular momentum stars in the associated central regions of the galaxy, must be in predominantly chaotic orbits. Some theoretical arguments to support the numerically derived outcomes are presented. Comparison with similar previous works is also made.Comment: Published in New Astronomy journa

Are external perturbations responsible for chaotic motion in galaxies?

We study the nature of motion in a logarithmic galactic dynamical model, with an additional external perturbation. Two different cases are investigated. In the first case the external perturbation is fixed, while in the second case it is varying with the time. Numerical experiments suggest, that responsible for the chaotic phenomena is the external perturbation, combined with the dense nucleus. Linear relationships are found to exist, between the critical value of the angular momentum and the dynamical parameters of the galactic system that is, the strength of the external perturbation, the flattening parameter and the radius of the nucleus. Moreover, the extent of the chaotic regions in the phase plane, increases linearly as the strength of the external perturbation and the flattening parameter increases. On the contrary, we observe that the percentage covered by chaotic orbits in the phase plane, decreases linearly, as the scale length of the nucleus increases, becoming less dense. Theoretical arguments are used to support and explain the numerically obtained outcomes. A comparison of the present outcomes with earlier results is also presented.Comment: Published in Chaos, Solitons & Fractals journa

Application of new dynamical spectra of orbits in Hamiltonian systems

In the present article, we investigate the properties of motion in Hamiltonian systems of two and three degrees of freedom, using the distribution of the values of two new dynamical parameters. The distribution functions of the new parameters, define the S(g) and the S(w) dynamical spectra. The first spectrum definition, that is the S(g) spectrum, will be applied in a Hamiltonian system of two degrees of freedom (2D), while the S(w) dynamical spectrum will be deployed in a Hamiltonian system of three degrees of freedom (3D). Both Hamiltonian systems, describe a very interesting dynamical system which displays a large variety of resonant orbits, different chaotic components and also several sticky regions. We test and prove the efficiency and the reliability of these new dynamical spectra, in detecting tiny ordered domains embedded in the chaotic sea, corresponding to complicated resonant orbits of higher multiplicity. The results of our extensive numerical calculations, suggest that both dynamical spectra are fast and reliable discriminants between different types of orbits in Hamiltonian systems, while requiring very short computation time in order to provide solid and conclusive evidence regarding the nature of an orbit. Furthermore, we establish numerical criteria in order to quantify the results obtained from our new dynamical spectra. A comparison to other previously used dynamical indicators, reveals the leading role of the new spectra.Comment: Published in Nonlinear Dynamics (NODY) journal. arXiv admin note: text overlap with arXiv:1009.1993 by other author

A Study of the Orbits of the Logarithmic Potential for Galaxies

The logarithmic potential is of great interest and relevance in the study of the dynamics of galaxies. Some small corrections to the work of Contopoulos & Seimenis (1990) who used the method of Prendergast (1982) to find periodic orbits and bifurcations within such a potential are presented. The solution of the orbital radial equation for the purely radial logarithmic potential is then considered using the p-ellipse (precessing ellipse) method pioneered by Struck (2006). This differential orbital equation is a special case of the generalized Burgers equation. The apsidal angle is also determined, both numerically as well as analytically by means of the Lambert W and the Polylogarithm functions. The use of these functions in computing the gravitational lensing produced by logarithmic potentials is discussed.Comment: 12 pages, 4 figures. Accepted by MNRAS Sept 6 201

Correlation of [18F]FDG PET activity with expressions of Ki-67 in non-small-cell lung cancer

Background: Lung carcinoma is the most commonly diagnosed cancer throughout the world and is the leading cause of cancer-related deaths. Non-small cell lung cancer (NSCLC) accounts for up to 80% of newly diagnosed lung cancer cases. This study aimed to investigate the relationship between Ki-67 proliferation index (PI) and the maximum standardized uptake value (SUVmax) obtained from [18F]FDG PET/CT in NSCLCs and whether prognosis was predicted with SUVmax values.Material and methods: This retrospective study included biopsy and resection materials of 41 patients, who were examined in the pathology laboratory of Konya Training and Research Hospital between January 2010 and December 2019, and diagnosed with NSCLC, and whose [18F]FDG PET/CT images were present.Results: There was no significant difference between histopathological subtypes in terms of age (p = 0.077), Ki-67 PI (p = 0.454), and SUVmax (p = 0.143). No correlation was observed between Ki-67 PI and SUVmax values obtained from [18F]FDG PET/CT (p = 0.338, r = 0.153). There was no significant correlation between Ki-67 PI and tumor diameter (p = 0.531). The SUVmax value was found to be lower (12.78 ± 6.14) in tumors measuring ≤ 2.5 in diameter and higher (18.46 ± 7.81) in tumors measuring > 2.5 cm (p = 0.027). Metastases not proven histopathologically but detected in [18F]FDG PET/CT were found to have no significant correlation with Ki-67 and SUVmax values (p = 0.881, p = 0.837).Conclusions: This study showed that there was no significant relationship between Ki-67 PI and SUVmax value obtained from [18F]FDG PET/CT in NSCLC tumors

Case Report Pulmonary Hyalinizing Granuloma Mimicking Metastatic Lung Cancer

Pulmonary hyalinizing granuloma is a very rare benign condition, which usually manifests as solitary and sometimes as multiple pulmonary nodules. Deposition of immune complexes in the lung parenchyma due to hypersensitivity reactions is implicated in the etiology of pulmonary hyalinizing granuloma. A 59-year-old female patient who presented to our clinic with complaints of chest pain and cough had bilateral, multiple, and rounded lesions with regular margins suggesting metastatic lung disease. A transthoracic needle biopsy of the nodule was performed in the left pulmonary anterior segment. Biopsy showed no malignancy. Since no diagnosis was made by the biopsy, the patient underwent a video-assisted thoracic surgery. The wedge biopsy reported pulmonary hyalinizing granuloma. We aimed to present the diagnosis and treatment stages of our patient who was diagnosed with pulmonary hyalinizing granuloma in the light of literature review

First report of Cryptosporidium hominis in a freshwater sponge

Identification of Cryptosporidium oocyst is essential in ensuring water quality fit for human use, consumption, and recreation.This communication proposes the supplemental analysis of substrateassociated biofilms, in particular, freshwater sponges in improving case finding of waterborne-protozoan pathogens (WBPP) in environmental aquatic samples. In this study, a small portion of a mature freshwater sponge under the Genus Radiospongilla was subjected to microscopic and molecular analysis to identify the presence of Cryptosporidium. Microscopic screening with modified Kinyoun's staining (MK) and microscopic confirmation using direct antibody fluorescent testing (IFT) returned with Cryptosporidium spp. positive findings. Molecular investigation resulted in the confirmation of Cryptosporidium hominis upon sequencing of PCR products and phylogenetic analysis. This is the first report of a pathogenic protozoan, C. hominis isolated from a freshwater sponge. The results of this study provide evidence of the value of expanding water quality assessment strategies to the analysis of substrate-associated biofilms and sponges in improving case finding of WBPP in natural aquatic environments