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Search Results: 1 - 10 of 461884 matches for " Just A. "
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Die ovarielle Stimulation und Ovulationsinduktion in der Assistierten Reproduktion
Just A,Obruca A
Journal für Fertilit?t und Reproduktion , 2002,
Abstract: Im Jahre 1978 wurde mit der Geburt des ersten Kindes nach erfolgreicher in vitro-Fertilisation und anschlie endem Embryotransfer eine neue ra der Reproduktionsmedizin eingeleitet. Das Indikationsspektrum der Assistierten Reproduktion (ART) hat sich seither - vor allem durch die Einführung der intrazytoplasmatischen Spermieninjektion (ICSI) als eine Routinemethode - stark gewandelt und erweitert. Der Arbeitsgruppe um Alan Trounson ist es zu verdanken, da die in der Tiermedizin gewonnen Erkenntnisse um die M glichkeit einer kontrollierten überstimulation (COH) in den 80er Jahren den Einzug in die Humanmedizin gehalten haben. Eine suffizient kontrollierte ovarielle überstimulation ist bis heute Grundlage für den Behandlungserfolg des Paares und erm glicht die Gewinnung einer genügenden Anzahl von reifen Oozyten. Gleichzeitig werden indirekt z. B. nachfolgende labortechnische Schritte durch diese beeinflu t.
Roche volume filling of star clusters in the Milky Way
A. Ernst,A. Just
Physics , 2012, DOI: 10.1093/mnras/sts530
Abstract: We examine the ratios $r_h/r_J$ of projected half-mass and Jacobi radius as well as $r_t/r_J$ of tidal and Jacobi radius for open and globular clusters in the Milky Way using data of both observations and simulations. We applied an improved calculation of $r_J$ for eccentric orbits of globular clusters. A sample of 236 open clusters of Piskunov et al. within the nearest kiloparsec around the Sun has been used. For the Milky Way globular clusters, data are taken from the Harris catalogue. We particularly use the subsample of 38 Milky Way globular clusters for which orbits have been integrated by Dinescu et al. We aim to quantify the differences between open and globular clusters and to understand, why they form two intrinsically distinct populations. We find under certain assumptions, or, in other words, in certain approximations, (i) that globular clusters are presently Roche volume underfilling and (ii) with at least $3\sigma$ confidence that the ratio $r_h/r_J$ of half-mass and Jacobi radius is $3 - 5$ times larger at present for an average open cluster in our sample than for an average globular cluster in our sample and (iii) that a significant fraction of globular clusters may be Roche volume overfilling at pericentre with $r_t > r_J$. Another aim of this paper is to throw light on the underlying theoretical reason for the existence of the van den Bergh correlation between half-mass and galactocentric radius.
Towards a fully consistent Milky Way disc model: Part 1 The local model based on kinematic and photometric data
A. Just,H. Jahreiss
Physics , 2009, DOI: 10.1111/j.1365-2966.2009.15893.x
Abstract: We present a fully consistent evolutionary disc model of the solar cylinder. The model is based on a sequence of stellar sub-populations described by the star formation history (SFR) and the dynamical heating law (given by the age-velocity dispersion relation AVR). The combination of kinematic data from Hipparcos and the finite lifetimes of main sequence (MS) stars enables us to determine the detailed vertical disc structure independent of individual stellar ages and only weakly dependent on the IMF. The disc parameters are determined by applying a sophisticated best fit algorithm to the MS star velocity distribution functions in magnitude bins. We find that the AVR is well constrained by the local kinematics, whereas for the SFR the allowed range is larger. A simple chemical enrichment model is included in order to fit the local metallicity distribution of G dwarfs. In our favoured model A the power law index of the AVR is 0.375 with a minimum and maximum velocity dispersion of 5.1 km/s and 25.0 km/s, respectively. The SFR shows a maximum 10 Gyr ago and declines by a factor of four to the present day value of 1.5 M_sun/pc^2/Gyr. A best fit of the IMF leads to power-law indices of -1.46 below and -4.16 above 1.72 M_sun avoiding a kink at 1 M_sun. An isothermal thick disc component with local density of ~6% of the stellar density is included. A thick disc containing more than 10% of local stellar mass is inconsistent with the local kinematics of K and M dwarfs.
Impact of cosmological satellites on the vertical heating of the Milky Way disc
R. Moetazedian,A. Just
Physics , 2015,
Abstract: We present a high resolution study of the impact of realistic satellite galaxies, extracted from cosmological simulations of Milky Way haloes including 6 Aquarius suites and Via Lactea \rom{2}, on the dynamics of the galactic disc. The initial conditions for the multi-component Milky Way galaxy were generated using the GalIC code, to ensure a system in real equilibrium state prior to addition of satellites. The candidate subhaloes that came closer than 25 kpc to the centre of the host DM haloes, with initial mass $M_\textrm{tid}$ $\ge$ 10$^{8}$=0.003 $M_\textrm{tid}$/$M_\textrm{disc}$, were identified, inserted into our high resolution N-body simulations and evolved for 2 Gyrs. We quantified the vertical heating due to such impacts by measuring the disc thickness, root-mean-square of $z$-coordinate, and vertical velocity dispersion $\sigma_{z}^{2}$ across the disc. According to our analysis the strength of the heating is strongly dependent on the high mass end of the subhalo distribution from the cosmological simulations. The mean increase of the vertical dispersion is $\sim$ 25 km$^{2}$s$^{-2}$Gyr$^{-1}$ for R $>$ 4 kpc while, if we exclude Aq-F-2 results, the mean heating is $<$ 12 km$^{2}$s$^{-2}$Gyr$^{-1}$. The observed vertical heating rate in the solar neighbourhood has a value of 67 km$^{2}$s$^{-2}$Gyr$^{-1}$; taking into account the 1$\sigma$ statistical dispersion around the mean we lie just below the observed value of 144 km$^{2}$s$^{-2}$ after 2 Gyrs. We observed a general flaring of the disc height in the case of all 7 simulations in the outer disc where the thickness was increased by $\sim$ 40% at 15 kpc. The 1$\sigma$ cosmic variance corresponds to doubling the disc thickness in the outer region.
Analogues of the Smale and Hirsch Theorems for Cooperative Boolean and Other Discrete Systems
Winfried Just,German A. Enciso
Mathematics , 2007,
Abstract: Discrete dynamical systems defined on the state space {0,1,...,p-1}^n have been used in multiple applications, most recently for the modeling of gene and protein networks. In this paper we study to what extent well-known theorems by Smale and Hirsch, which form part of the theory of (continuous) monotone dynamical systems, generalize or fail to do so in the discrete case. We show that that arbitrary m-dimensional systems cannot necessarily be embedded into n-dimensional cooperative systems for n=m+1, as in the Smale theorem for the continuous case, but we show that this is possible for n=m+2 as long as p is sufficiently large. We also prove that a natural discrete analogue of strong cooperativity implies nontrivial bounds on the lengths of periodic orbits and imposes a condition akin to Lyapunov stability on all attractors. Finally, we explore several natural candidates for definitions of irreducibility of a discrete system. While some of these notions imply the strong cooperativity of a given cooperative system and impose even tighter bounds on the lengths of periodic orbits than strong cooperativity alone, other plausible definitions allow the existence of exponentially long periodic orbits.
Large attractors in cooperative bi-quadratic Boolean networks. Part I
German A. Enciso,Winfried Just
Quantitative Biology , 2007,
Abstract: Boolean networks have been the object of much attention, especially since S. Kauffman proposed them in the 1960's as models for gene regulatory networks. These systems are characterized by being defined on a Boolean state space and by simultaneous updating at discrete time steps. Of particular importance for biological applications are networks in which the indegree for each variable is bounded by a fixed constant, as was stressed by Kauffman in his original papers. An important question is which conditions on the network topology can rule out exponentially long periodic orbits in the system. In this paper, we consider systems with positive feedback interconnections among all variables (known as cooperative systems), which in a continuous setting guarantees a very stable dynamics. We show that for an arbitrary constant 0
Daring to Dare—Theoretical Experiment for Pedagogical Practices and Body-Brain-Embedded Subject  [PDF]
Edyta Just
Creative Education (CE) , 2016, DOI: 10.4236/ce.2016.72028
Abstract: This article discusses and experiments with a psychological constructionist account of the brain basis of emotion—the conceptual act model (Lindquist et al., 2012; Barrett et al., 2014) and the Deleuzian and Guattarian (1987; 2009) philosophical accounts of affect, concept and stratum. Why those two? The conceptual act model theorizes process of meaning making of external and internal sensations including experience of emotions. Deleuze and Guattari, with their accounts, reflect on various patterns of making meaning comprising those that lead to self-/criticism and creativity. Since it is crucial to think about teaching practices that support students in daring to challenge, problematize and generate new meaning of experienced sensations, theories that address meaning making processes are of particular relevance. This article shows that those theories alone and once exposed to an experiment may possibly inspire pedagogical undertakings that aim to create self-/critically-creative abilities among students, but also add to the ways of conceptualizing subject, body, mind and brain.
Daring the Meaning, or Cyberspace that Matters. Criticism-Creativity and Online Education  [PDF]
Edyta Just
Creative Education (CE) , 2018, DOI: 10.4236/ce.2018.913147
Abstract: This paper focuses on online education and generic competences such as criticism and creativity. It brings to the fore theories that address processes of meaning making (i.e., a psychological constructionist account of the brain basis of emotion-the conceptual act model (Lindquist et al., 2012; Barrett et al., 2014) and reflect on various patterns of meaning making comprising those that lead to criticism and creativity (i.e., the Deleuzian and Guattarian (1987; 2009) philosophical accounts of affect, concept and stratum) to inspire pedagogical practices that aim to create critically-creative abilities among students. Concomitantly, it seeks to reflect on how such pedagogical undertakings can be actualized in online education and on the possibilities online environment offers to promote criticism and creativity among graduates. By posing questions related to teaching methods, learning activities, software and hardware, and their combinations in online education, and by addressing and problematizing concepts and phenomena of immersion and DFI-digital facial image, I will make an effort to not only highlight, what I call, the promises of cyberspace, but also ponder on how the aforementioned pedagogical practices can be actualized online.
Endometriose - operative Standardbeschreibung
Just A,Wenzl R,Huber J
Speculum - Zeitschrift für Gyn?kologie und Geburtshilfe , 2008,
Abstract:
A detailed self-consistent vertical Milky Way disc model
Just A.,Golubov O.,Gao S.
EPJ Web of Conferences , 2012, DOI: 10.1051/epjconf/20121910007
Abstract: We present a self-consistent vertical disc model of thin and thick disc in the solar vicinity. The model is optimized to fit the local kinematics of main sequence stars by varying the star formation history and the dynamical heating function. The star formation history and the dynamical heating function are not uniquely determined by the local kinematics alone. For four different pairs of input functions we calculate star count predictions at high galactic latitude as a function of colour. The comparison with North Galactic Pole data of SDSS/SEGUE leads to significant constraints of the local star formation history.
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