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Preliminary Information on the Vertebrate Fauna (Animalia: Vertebrata) of the NATURA2000 Site “Rice Fields Tsalapitsa” (Bulgaria)
Ivayla L. Klimentova,Dimitar G. Plachyiski,Dilian G. Georgiev
Ecologia Balkanica , 2011,
Abstract: The study was carried out by tree visits in different areas of the Natura 2000 site “Rice Fields Tsalapitsa” BG 0002086 (West of Plovdiv city, near village of Tsalapitsa). Our preliminary research showed that in the area vertebrates with high conservation status occurred included in the Bulgarian Bidiversity Act, Appendix II and III, Appendix II of the Bern convention, Natura 2000 species list, the Bonn convention, Appendix II, the Convention of the International Trade of Endangered Species, and the list of the International Union for Conservation of the Nature. This information will help in future preparation of the management plan of the Natura 2000 site and showed the need of studies focused on such areas which will help undertaking adequate measures for their proper way of conservation.
Sleeping Giants? - X-ray search for low-luminosity AGN candidates in nearby optically bright galaxies
Ivayla E. Kalcheva
Physics , 2014,
Abstract: In this Master's project, the X-ray nuclear properties of a sample of bright nearby galaxies are explored. This is done by matching their comprehensive optical spectroscopic classification to the latest available XMM-Newton catalogue - 3XMM-DR4. The good coverage (approx. 38 per cent) ensures that a statistically representative sample is investigated. All nuclear and morphological subsets found within the original sample of 486 galaxies are encompassed, but early-type galaxies and galaxies with optical features characteristic for active galactic nuclei (AGN) are favoured. The results from the investigation of the properties of our cross-matched sample are overall consistent with the presence of a large fraction of X-ray - detected low-luminosity AGN (LLAGN). The X-ray - detected galaxies within our HII and transition-LINER subsets are of particular interest, as they could harbour LLAGN missed by optical spectroscopic selection. The properties of these nuclei are explored by X-ray spectral fitting of available XMM-Newton observations. The majority of the examined spectra are found to be consistent with a thermal plasma model and an underlying power-law continuum, and the relative contributions of a potential LLAGN and of thermal emission to the source luminosity are presented. In the case that these spectra are not highly contaminated, as confirmed for some of the nuclei by examining available higher-resolution Chandra images, we classify approx. 43 per cent of the HII nuclei and 40 per cent of the transition-LINER nuclei as optically undetected LLAGN-candidates. This classification is found to be reasonably successful, given the project limitations, when compared to X-ray and multi-wavelength results found in literature for many of the nuclei.
An ultrasensitive sorting mechanism for EGF Receptor Endocytosis
Hannah Schmidt-Glenewinkel, Ivayla Vacheva, Daniela Hoeller, Ivan Dikic, Roland Eils
BMC Systems Biology , 2008, DOI: 10.1186/1752-0509-2-32
Abstract: Here, we present a mathematical model of receptor sorting into alternative pathways that explains the EGF-concentration dependent response of CIE. The described mechanism involves a saturation effect of the dominant clathrin-dependent endocytosis pathway and implies distinct steady-states into which the system is forced for low vs high EGF stimulations. The model is minimal since no experimentally unjustified reactions or parameter assumptions are imposed. We demonstrate the robustness of the sorting effect for large parameter variations and give an analytic derivation for alternative steady-states that are reached. Further, we describe extensibility of the model to more than two pathways which might play a role in contexts other than receptor internalization.Our main result is that a scenario where different endocytosis routes consume the same form of receptor corroborates the observation of a clear-cut, stimulus dependent sorting. This is especially important since a receptor modification discriminating between the pathways has not been found experimentally. The model is not restricted to EGF receptor internalization and might account for ultrasensitivity in other cellular contexts.Endocytosis is the process by which activated transmembrane receptors are directed into the endosomal system from the plasma membrane [1-4]. In the past years, it has emerged as a powerful mechanism for the cell to temporally and spatially control its signaling response [5]. Ligand induced phosphorylation of EGF receptor creates docking sites for adaptor proteins, such as EPS15, epsin and AP-2 [6,7]. Via direct or indirect binding, adaptors recruit the receptor to special membrane regions which are characterized by a particular composition of cage-proteins and/or -lipids [8,9]. The forming vesicles pinch off the membrane and carry their cargo to distinct intracellular locations, which might account for the specificity of the invoked signal [1,10]. Endocytosis may direct the receptors fo
Cd(II) and Pb(II) complexes of the polyether ionophorous antibiotic salinomycin
Juliana Ivanova, Ivayla N Pantcheva, Mariana Mitewa, Svetlana Simova, Makoto Tanabe, Kohtaro Osakada
Chemistry Central Journal , 2011, DOI: 10.1186/1752-153x-5-52
Abstract: New metal(II) complexes of the polyether ionophorous antibiotic salinomycin with Cd(II) and Pb(II) ions were prepared and structurally characterized by IR, FAB-MS and NMR techniques. The spectroscopic information and elemental analysis data reveal that sodium salinomycin (SalNa) undergoes a reaction with heavy metal(II) ions to form [Cd(Sal)2(H2O)2] (1) and [Pb(Sal)(NO3)] (2), respectively. Abstraction of sodium ions from the cavity of the antibiotic is occurring during the complexation reaction. Salinomycin coordinates with cadmium(II) ions as a bidentate monoanionic ligand through the deprotonated carboxylic moiety and one of the hydroxyl groups to yield 1. Two salinomycin anions occupy the equatorial plane of the Cd(II) center, while two water molecules take the axial positions of the inner coordination sphere of the metal(II) cation. Complex 2 consists of monoanionic salinomycin acting in polydentate coordination mode in a molar ratio of 1: 1 to the metal ion with one nitrate ion for charge compensation.The formation of the salinomycin heavy metal(II) complexes indicates a possible antidote activity of the ligand in case of chronic/acute intoxications likely to occur in the stock farming.The natural polyether ionophorous antibiotics produced by Streptomyces spp. are used for the treatment of coccidiosis in poultry (chickens, turkeys and quail) and ruminants (cattle, sheep and goats). They are agents controlling ketosis and bloat in cattle and are applied as growth promoter feed additives in cattle and sheep. The polyether ionophores are mainly effective against Gram-positive bacteria, interfering with ion flux across bacterial membranes thus causing reallocation of bacterial energy resources to maintain cellular pH and ion balance. Effects on feed conversion efficiency arise from the ability of antibiotics to shift rumen fermentation towards the more energetically efficient propionate pathway, to reduce methane production and to increase nitrogen retention by re
Computing Reachable Sets as Capture-Viability Kernels in Reverse Time  [PDF]
No?l Bonneuil
Applied Mathematics (AM) , 2012, DOI: 10.4236/am.2012.311219
Abstract: The set SF(x0;T) of states y reachable from a given state x0 at time T under a set-valued dynamic x’(t)∈F(x (t)) and under constraints x(t)∈K where K is a closed set, is also the capture-viability kernel of x0 at T in reverse time of the target {x0} while remaining in K. In dimension up to three, Saint-Pierre’s viability algorithm is well-adapted; for higher dimensions, Bonneuil’s viability algorithm is better suited. It is used on a large-dimensional example.
Three Dimensional Evolution of SN 1987A in a Self-Gravitating Disk  [PDF]
L. Zaninetti
International Journal of Astronomy and Astrophysics (IJAA) , 2013, DOI: 10.4236/ijaa.2013.32010
Abstract:

The introduction of an exponential or power law gradient in the interstellar medium (ISM) allows to produce an asymmetric evolution of the supernova remnant (SNR) when the framework of the thin layer approximation is adopted. Unfortunately both the exponential and power law gradients for the ISM do not have a well defined physical meaning. The physics conversely is well represented by an isothermal self-gravitating disk of particles whose velocity is everywhere Maxwellian. We derived a law of motion in the framework of the thin layer approximation with a control parameter of the swept mass. The photon’s losses, which are often neglected in the thin layer approximation, are modeled trough velocity dependence. The developed framework is applied to SNR 1987A and the three observed rings are simulated.

The Luminosity Function of Galaxies as Modeled by a Left Truncated Beta Distribution  [PDF]
L. Zaninetti
International Journal of Astronomy and Astrophysics (IJAA) , 2014, DOI: 10.4236/ijaa.2014.41013
Abstract: A first new luminosity function of galaxies can be built starting from a left truncated beta probability density function, which is characterized by four parameters. In the astrophysical conversion, the number of parameters increases by one, due to the addition of the overall density of galaxies. A second new galaxy luminosity function is built starting from a left truncated beta probability for the mass of galaxies once a simple nonlinear relationship between mass and luminosity is assumed; in this case the number of parameters is six because the overall density of galaxies and a parameter that regulates mass and luminosity are added. The two new galaxy luminosity functions with finite boundaries were tested on the Sloan Digital Sky Survey (SDSS) in five different bands; the results produce a better fit than the Schechter luminosity function in two of the five bands considered. A modified Schechter luminosity function with four parameters has been also analyzed.
On the Dark Matter’s Halo Theoretical Description  [PDF]
L. M. L. M. Chechin
Journal of Modern Physics (JMP) , 2012, DOI: 10.4236/jmp.2012.35052
Abstract: We argued that the standard field scalar potential couldn’t be widely used for getting the adequate galaxies’ curve lines and determining the profiles of dark matter their halo. For discovering the global properties of scalar fields that can describe the observable characteristics of dark matter on the cosmological space and time scales, we propose the simplest form of central symmetric potential celestial-mechanical type, i.e. U(φ) = –μ/φ. It was shown that this potential allows get rather satisfactorily dark matter profiles and rotational curves lines for dwarf galaxies. The good agreement with some previous results, based on the N-body simulation method, was pointed out. A new possibility of dwarf galaxies’ masses estimation was given, also.
Quantization and Stable Attractors in a DissipativeOrbital Motion  [PDF]
Daniel L. Nascimento, Antonio L. A. Fonseca
Journal of Modern Physics (JMP) , 2011, DOI: 10.4236/jmp.2011.24030
Abstract: We present a method for determining the motion of an electron in a hydrogen atom, which starts from a field Lagrangean foundation for non-conservative systems that can exhibit chaotic behavior. As a consequence, the problem of the formation of the atom becomes the problem of finding the possible stable orbital attractors and the associated transition paths through which the electron mechanical energy varies continuously until a stable energy state is reached.
Genetic and dietary factors related to schizophrenia  [PDF]
Karl L. Reichelt, Michael L. G. Gardner
Open Journal of Psychiatry (OJPsych) , 2012, DOI: 10.4236/ojpsych.2012.21003
Abstract: Biochemical, immunological and epidemiological evidence increasingly support the suggestion that there is a causal relationship between gluten/gliadin and schizophrenia as originally proposed by F. C. Dohan. Furthermore the necessary physiological mechanisms exist to explain a mechanism involving bioactive peptides from these proteins, and these show that this mechanism is possible and probable in at least in a substantial subgroup of schizophrenic patients. Evidence shows a fairly strong genetic disposition, and it must be recognised that any genetic mechanism must implicate altered chemistry and function of proteins. Evidence supports the likelihood that dietary intervention is beneficial for some, and this demands further investigation. A similar conclusion may apply to autism spectrum conditions.
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