The Experts below are selected from a list of 45 Experts worldwide ranked by ideXlab platform

Luisa Ostorero - One of the best experts on this subject based on the ideXlab platform.

  • Distribution of phantom dark matter in dwarf spheroidals
    arXiv: Astrophysics of Galaxies, 2020
    Co-Authors: Alistair O Hodson, Antonaldo Diaferio, Luisa Ostorero
    Abstract:

    We derive the Distribution of the phantom dark matter in the eight classical dwarf galaxies surrounding the Milky Way, under the assumption that modified Newtonian dynamics (MOND) is the correct theory of gravity. According to their observed shape, we model the dwarfs as axisymmetric systems, rather than spherical systems, as usually assumed. In addition, as required by the assumption of the MOND framework, we realistically include the external gravitational field of the Milky Way and of the large-scale structure beyond the Local Group. For the dwarfs where the external field dominates over the internal gravitational field, the phantom dark matter has, from the Star Distribution, an offset of ~0.1-0.2 kpc, depending on the mass-to-light ratio adopted. This offset is a substantial fraction of the dwarf half-mass radius. For Sculptor and Fornax, where the internal and external gravitational fields are comparable, the phantom dark matter Distribution appears disturbed with spikes at the locations where the two fields cancel each other; these features have little connection with the Distribution of the Stars within the dwarfs. Finally, we find that the external field due to the large-scale structure beyond the Local Group has a very minor effect. The features of the phantom dark matter we find represent a genuine prediction of MOND, and could thus falsify this theory of gravity in the version we adopt here if they are not observationally confirmed.

  • on the Distribution of phantom dark matter in dwarf spheroidals
    arXiv: Astrophysics of Galaxies, 2020
    Co-Authors: Alistair O Hodson, Antonaldo Diaferio, Luisa Ostorero
    Abstract:

    We derive the Distribution of the phantom dark matter in the eight classical dwarf galaxies surrounding the Milky Way, under the assumption that MOND is the correct theory of gravity. According to their observed shape, we model the dwarves as axi-symmetric systems, rather than spherical systems, as usually assumed. In addition, as required by the assumption of the MOND framework, we realistically include the external gravitational field of the Milky Way and of the large-scale structure beyond the Local Group. For the dwarves where the external field dominates over the internal gravitational field, the phantom dark matter has, from the Star Distribution, an offset of ~0.1-0.2 kpc, depending on the mass-to-light ratio adopted. This offset is a substantial fraction of the dwarf half-mass radius. For Sculptor and Fornax, where the internal and external gravitational fields are comparable, the phantom dark matter Distribution appears disturbed with spikes at the locations where the two fields cancel each other; these features have little connection with the Distribution of the Stars within the dwarves. Finally, we find that the external field due to the large-scale structure beyond the Local Group has a very minor effect. The features of the phantom dark matter we find represent a genuine prediction of MOND and could thus falsify this theory of gravity, in the version we adopt here, if they were not observationally confirmed.

Alistair O Hodson - One of the best experts on this subject based on the ideXlab platform.

  • Distribution of phantom dark matter in dwarf spheroidals
    arXiv: Astrophysics of Galaxies, 2020
    Co-Authors: Alistair O Hodson, Antonaldo Diaferio, Luisa Ostorero
    Abstract:

    We derive the Distribution of the phantom dark matter in the eight classical dwarf galaxies surrounding the Milky Way, under the assumption that modified Newtonian dynamics (MOND) is the correct theory of gravity. According to their observed shape, we model the dwarfs as axisymmetric systems, rather than spherical systems, as usually assumed. In addition, as required by the assumption of the MOND framework, we realistically include the external gravitational field of the Milky Way and of the large-scale structure beyond the Local Group. For the dwarfs where the external field dominates over the internal gravitational field, the phantom dark matter has, from the Star Distribution, an offset of ~0.1-0.2 kpc, depending on the mass-to-light ratio adopted. This offset is a substantial fraction of the dwarf half-mass radius. For Sculptor and Fornax, where the internal and external gravitational fields are comparable, the phantom dark matter Distribution appears disturbed with spikes at the locations where the two fields cancel each other; these features have little connection with the Distribution of the Stars within the dwarfs. Finally, we find that the external field due to the large-scale structure beyond the Local Group has a very minor effect. The features of the phantom dark matter we find represent a genuine prediction of MOND, and could thus falsify this theory of gravity in the version we adopt here if they are not observationally confirmed.

  • on the Distribution of phantom dark matter in dwarf spheroidals
    arXiv: Astrophysics of Galaxies, 2020
    Co-Authors: Alistair O Hodson, Antonaldo Diaferio, Luisa Ostorero
    Abstract:

    We derive the Distribution of the phantom dark matter in the eight classical dwarf galaxies surrounding the Milky Way, under the assumption that MOND is the correct theory of gravity. According to their observed shape, we model the dwarves as axi-symmetric systems, rather than spherical systems, as usually assumed. In addition, as required by the assumption of the MOND framework, we realistically include the external gravitational field of the Milky Way and of the large-scale structure beyond the Local Group. For the dwarves where the external field dominates over the internal gravitational field, the phantom dark matter has, from the Star Distribution, an offset of ~0.1-0.2 kpc, depending on the mass-to-light ratio adopted. This offset is a substantial fraction of the dwarf half-mass radius. For Sculptor and Fornax, where the internal and external gravitational fields are comparable, the phantom dark matter Distribution appears disturbed with spikes at the locations where the two fields cancel each other; these features have little connection with the Distribution of the Stars within the dwarves. Finally, we find that the external field due to the large-scale structure beyond the Local Group has a very minor effect. The features of the phantom dark matter we find represent a genuine prediction of MOND and could thus falsify this theory of gravity, in the version we adopt here, if they were not observationally confirmed.

Santillo A - One of the best experts on this subject based on the ideXlab platform.

  • Star protein and steroidogenic enzyme expressions in the rat Harderian gland
    2018
    Co-Authors: Falvo S, Gc Baccari, Spaziano G, Rosati L, Venditti M, Mm ,di Fiore, Santillo A
    Abstract:

    The Harderian gland (HG) of the rat (Rattus norvegicus) secretes copious amounts of lipids, such as cholesterol. Here we report a study of the expressions of the Star protein and key steroidogenic enzymes in the HG of male and female rats. The objective of the present investigation was to ascertain (a) whether the rat HG is involved in steroid production Starting with cholesterol, and (b) whether the pattern of gene and protein expressions together with the enzymatic activities display sexual dimorphism. The results demonstrate, for the first time, the expression of Star gene and protein, and Cyp11a1, Hsd3b1, Hsd17b3, Srd5a1, Srd5a2 and Cyp19a1 genes in the rat HG. Star mRNA and protein expressions were much greater in males than in females. Immunohistochemical analysis demonstrated a non-homogeneous Star Distribution among glandular cells. Hsd17b3 and Cyp19a1 mRNA levels were higher in males than in females, whereas Srd5a1 mRNA levels were higher in females than in males. No significant differences were observed in mRNA levels of Cyp11a1, Hsd3b1 and Srd5a2 between sexes. Furthermore, the in vitro experiments demonstrated a higher 5a-reductase activity in the female as compared to the male HG vice versa a higher P450 aro activity in males as compared to females. These results suggest that the Harderian gland can be classified as a steroidogenic tissue because it synthesizes cholesterol, expresses Star and steroidogenic enzymes involved in both androgen and estrogen synthesis. The dimorphic expression and activity of the steroidogenic enzymes may suggest sex-specific hormonal effects into the HG physiology.The Harderian gland (HG) of the rat (Rattus norvegicus) secretes copious amounts of lipids, such as cholesterol. Here we report a study of the expressions of the Star protein and key steroidogenic enzymes in the HG of male and female rats. The objective of the present investigation was to ascertain (a) whether the rat HG is involved in steroid production Starting with cholesterol, and (b) whether the pattern of gene and protein expressions together with the enzymatic activities display sexual dimorphism. The results demonstrate, for the first time, the expression of Star gene and protein, and Cyp11a1, Hsd3b1, Hsd17b3, Srd5a1, Srd5a2 and Cyp19a1 genes in the rat HG. Star mRNA and protein expressions were much greater in males than in females. Immunohistochemical analysis demonstrated a non-homogeneous Star Distribution among glandular cells. Hsd17b3 and Cyp19a1 mRNA levels were higher in males than in females, whereas Srd5a1 mRNA levels were higher in females than in males. No significant differences were observed in mRNA levels of Cyp11a1, Hsd3b1 and Srd5a2 between sexes. Furthermore, the in vitro experiments demonstrated a higher 5 alpha-reductase activity in the female as compared to the male HG vice versa a higher P450 aro activity in males as compared to females. These results suggest that the Harderian gland can be classified as a steroidogenic tissue because it synthesizes cholesterol, expresses Star and steroidogenic enzymes involved in both androgen and estrogen synthesis. The dimorphic expression and activity of the steroidogenic enzymes may suggest sex-specific hormonal effects into the HG physiology. (C) 2018 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved

Maria Maddalena Di Fiore - One of the best experts on this subject based on the ideXlab platform.

  • Star protein and steroidogenic enzyme expressions in the rat Harderian gland.
    Comptes Rendus Biologies, 2018
    Co-Authors: Sara Falvo, Gabriella Chieffi Baccaria, Giuseppe Spaziano, Massimo Venditti, Luigi Rosati, Maria Maddalena Di Fiore
    Abstract:

    Abstract The Harderian gland (HG) of the rat (Rattus norvegicus) secretes copious amounts of lipids, such as cholesterol. Here we report a study of the expressions of the Star protein and key steroidogenic enzymes in the HG of male and female rats. The objective of the present investigation was to ascertain (a) whether the rat HG is involved in steroid production Starting with cholesterol, and (b) whether the pattern of gene and protein expressions together with the enzymatic activities display sexual dimorphism. The results demonstrate, for the first time, the expression of Star gene and protein, and Cyp11a1, Hsd3b1, Hsd17b3, Srd5a1, Srd5a2 and Cyp19a1 genes in the rat HG. Star mRNA and protein expressions were much greater in males than in females. Immunohistochemical analysis demonstrated a non-homogeneous Star Distribution among glandular cells. Hsd17b3 and Cyp19a1 mRNA levels were higher in males than in females, whereas Srd5a1 mRNA levels were higher in females than in males. No significant differences were observed in mRNA levels of Cyp11a1, Hsd3b1 and Srd5a2 between sexes. Furthermore, the in vitro experiments demonstrated a higher 5α-reductase activity in the female as compared to the male HG vice versa a higher P450 aro activity in males as compared to females. These results suggest that the Harderian gland can be classified as a steroidogenic tissue because it synthesizes cholesterol, expresses Star and steroidogenic enzymes involved in both androgen and estrogen synthesis. The dimorphic expression and activity of the steroidogenic enzymes may suggest sex-specific hormonal effects into the HG physiology.

Antonaldo Diaferio - One of the best experts on this subject based on the ideXlab platform.

  • Distribution of phantom dark matter in dwarf spheroidals
    arXiv: Astrophysics of Galaxies, 2020
    Co-Authors: Alistair O Hodson, Antonaldo Diaferio, Luisa Ostorero
    Abstract:

    We derive the Distribution of the phantom dark matter in the eight classical dwarf galaxies surrounding the Milky Way, under the assumption that modified Newtonian dynamics (MOND) is the correct theory of gravity. According to their observed shape, we model the dwarfs as axisymmetric systems, rather than spherical systems, as usually assumed. In addition, as required by the assumption of the MOND framework, we realistically include the external gravitational field of the Milky Way and of the large-scale structure beyond the Local Group. For the dwarfs where the external field dominates over the internal gravitational field, the phantom dark matter has, from the Star Distribution, an offset of ~0.1-0.2 kpc, depending on the mass-to-light ratio adopted. This offset is a substantial fraction of the dwarf half-mass radius. For Sculptor and Fornax, where the internal and external gravitational fields are comparable, the phantom dark matter Distribution appears disturbed with spikes at the locations where the two fields cancel each other; these features have little connection with the Distribution of the Stars within the dwarfs. Finally, we find that the external field due to the large-scale structure beyond the Local Group has a very minor effect. The features of the phantom dark matter we find represent a genuine prediction of MOND, and could thus falsify this theory of gravity in the version we adopt here if they are not observationally confirmed.

  • on the Distribution of phantom dark matter in dwarf spheroidals
    arXiv: Astrophysics of Galaxies, 2020
    Co-Authors: Alistair O Hodson, Antonaldo Diaferio, Luisa Ostorero
    Abstract:

    We derive the Distribution of the phantom dark matter in the eight classical dwarf galaxies surrounding the Milky Way, under the assumption that MOND is the correct theory of gravity. According to their observed shape, we model the dwarves as axi-symmetric systems, rather than spherical systems, as usually assumed. In addition, as required by the assumption of the MOND framework, we realistically include the external gravitational field of the Milky Way and of the large-scale structure beyond the Local Group. For the dwarves where the external field dominates over the internal gravitational field, the phantom dark matter has, from the Star Distribution, an offset of ~0.1-0.2 kpc, depending on the mass-to-light ratio adopted. This offset is a substantial fraction of the dwarf half-mass radius. For Sculptor and Fornax, where the internal and external gravitational fields are comparable, the phantom dark matter Distribution appears disturbed with spikes at the locations where the two fields cancel each other; these features have little connection with the Distribution of the Stars within the dwarves. Finally, we find that the external field due to the large-scale structure beyond the Local Group has a very minor effect. The features of the phantom dark matter we find represent a genuine prediction of MOND and could thus falsify this theory of gravity, in the version we adopt here, if they were not observationally confirmed.