Globular Cluster Streams as Galactic High-Precision Scales - The Poster Child Palomar 5

Using the example of the tidal stream of the Milky Way globular cluster Palomar 5 (Pal 5), we demonstrate how observational data on streams can be efficiently reduced in dimensionality and modeled in a Bayesian framework. Our approach combines detection of stream overdensities by a Difference-of-Gaussians process with fast streakline models, a continuous likelihood function built from these models, and inference with MCMC. By generating $\approx10^7$ model streams, we show that the geometry of the Pal 5 debris yields powerful constraints on the solar position and motion, the Milky Way and Pal 5 itself. All 10 model parameters were allowed to vary over large ranges without additional prior information. Using only SDSS data and a few radial velocities from the literature, we find that the distance of the Sun from the Galactic Center is $8.30\pm0.25$ kpc, and the transverse velocity is $253\pm16$ km/s. Both estimates are in excellent agreement with independent measurements of these quantities. Assuming a standard disk and bulge model, we determine the Galactic mass within Pal 5's apogalactic radius of 19 kpc to be $(2.1\pm0.4)\times10^{11}$ M$_\odot$. Moreover, we find the potential of the dark halo with a flattening of $q_z = 0.95^{+0.16}_{-0.12}$ to be essentially spherical within the radial range that is effectively probed by Pal 5. We also determine Pal 5's mass, distance and proper motion independently from other methods, which enables us to perform vital cross-checks. We conclude that with more observational data and by using additional prior information, the precision of this method can be significantly increased.Comment: 28 pages, 14 figures, submitted to ApJ (revised version), comments welcom

Modeling of leishmaniasis infection dynamics: novel application to the design of effective therapies

<p>Abstract</p> <p>Background</p> <p>The WHO considers leishmaniasis as one of the six most important tropical diseases worldwide. It is caused by parasites of the genus <it>Leishmania </it>that are passed on to humans and animals by the phlebotomine sandfly. Despite all of the research, there is still a lack of understanding on the metabolism of the parasite and the progression of the disease. In this study, a mathematical model of disease progression was developed based on experimental data of clinical symptoms, immunological responses, and parasite load for <it>Leishmania amazonensis </it>in <it>BALB/c </it>mice.</p> <p>Results</p> <p>Four biologically significant variables were chosen to develop a differential equation model based on the GMA power-law formalism. Parameters were determined to minimize error in the model dynamics and time series experimental data. Subsequently, the model robustness was tested and the model predictions were verified by comparing them with experimental observations made in different experimental conditions. The model obtained helps to quantify relationships between the selected variables, leads to a better understanding of disease progression, and aids in the identification of crucial points for introducing therapeutic methods.</p> <p>Conclusions</p> <p>Our model can be used to identify the biological factors that must be changed to minimize parasite load in the host body, and contributes to the design of effective therapies.</p

The leading Ruelle resonances of chaotic maps

The leading Ruelle resonances of typical chaotic maps, the perturbed cat map and the standard map, are calculated by variation. It is found that, excluding the resonance associated with the invariant density, the next subleading resonances are, approximately, the roots of the equation $z^4=\gamma$, where $\gamma$ is a positive number which characterizes the amount of stochasticity of the map. The results are verified by numerical computations, and the implications to the form factor of the corresponding quantum maps are discussed.Comment: 5 pages, 4 figures included. To appear in Phys. Rev.

Decolorization of Synthetic Textile Dyes by Fungal Endophytes Isolated from the Leaves of Philippine Mangrove (Avicennia marina)

Textile dyes in wastewater can be harmful pollutants when released into the environment without treatment. Biodegradation of textile dye effluents by different microbes, including fungi, has become popular as an alternative to physicochemical methods. The mangrove Avicennia marina is known to harbor endophytic fungi which have the potential to carry out dye degradation. Therefore, this study assessed the ability to decolorize synthetic dyes of endophytic fungi isolated from the leaves of A. marina. Of the nine fungal endophytes, Aspergillus niger, Syncephalastrum racemosum and Penicillium citrinum exhibited the highest mycelial growths in solid media, while all endophytes adsorbed Congo red. Through liquid decolorization assay, four isolates decolorized Congo red at greater than 89% decolorization rates. P. citrinum (55.45%), Mycelia sterilia (85.19%), A. flavus (44.91%) showed the highest decolorization rates of Methylene blue, Malachite green and Rhodamine B, respectively. The ligninolytic enzymes produced by the endophytic fungi, laccase exhibited the highest activity with values higher than the positive control

Renormalization of Quantum Anosov Maps: Reduction to Fixed Boundary Conditions

A renormalization scheme is introduced to study quantum Anosov maps (QAMs) on a torus for general boundary conditions (BCs), whose number ($k$) is always finite. It is shown that the quasienergy eigenvalue problem of a QAM for {\em all} $k$ BCs is exactly equivalent to that of the renormalized QAM (with Planck's constant $\hbar ^{\prime}=\hbar /k$) at some {\em fixed} BCs that can be of four types. The quantum cat maps are, up to time reversal, fixed points of the renormalization transformation. Several results at fixed BCs, in particular the existence of a complete basis of ``crystalline'' eigenstates in a classical limit, can then be derived and understood in a simple and transparent way in the general-BCs framework.Comment: REVTEX, 12 pages, 1 table. To appear in Physical Review Letter

Reversible Nanoparticle–Micelle Transformation of Ionic Liquid–Sulfonatocalix[6]arene Aggregates

The effect of temperature and NaCl concentration variations on the self-assembly of 1-methyl-3- tetradecylimidazolium (C14mim+) and 4-sulfonatocalix[6]- arene (SCX6) was studied by dynamic light scattering and isothermal calorimetric methods at pH 7. Inclusion complex formation promoted the self-assembly to spherical nanoparticles (NP), which transformed to supramolecular micelles (SM) in the presence of NaCl. Highly reversible, temperature-responsive behavior was observed, and the conditions of the NP−SM transition could be tuned by the alteration of C14mim+:SCX6 mixing ratio and NaCl concentration. The association to SM was always exothermic with enthalpy independent of the amount of NaCl. In contrast, NPs were produced in endothermic process at low temperature, and the enthalpy change became less favorable upon increase in NaCl concentration. The NP formation was accompanied by negative molar heat capacity change, which further diminished when NaCl concentration was raised

Kinematics with Gaia DR2 : the force of a dwarf

We use Gaia DR2 astrometric and line-of-sight velocity information combined with two sets of distances obtained with a Bayesian inference method to study the 3D velocity distribution in the Milky Way disc. We search for variations in all Galactocentric cylindrical velocity components (Vϕ, VR, and Vz) with Galactic radius, azimuth, and distance from the disc mid-plane. We confirm recent work showing that bulk vertical motions in the R–z plane are consistent with a combination of breathing and bending modes. In the x–y plane, we show that, although the amplitudes change, the structure produced by these modes is mostly invariant as a function of distance from the plane. Comparing to two different Galactic disc models, we demonstrate that the observed patterns can drastically change in short time intervals, showing the complexity of understanding the origin of vertical perturbations. A strong radial VR gradient was identified in the inner disc, transitioning smoothly from 16 km s−1 kpc−1 at an azimuth of 30° < ϕ < 45° ahead of the Sun-Galactic centre line to −16 km s−1 kpc−1 at an azimuth of −45° < ϕ < −30° lagging the solar azimuth. We use a simulation with no significant recent mergers to show that exactly the opposite trend is expected from a barred potential, but overestimated distances can flip this trend to match the data. Alternatively, using an N-body simulation of the Sagittarius dwarf–Milky Way interaction, we demonstrate that a major recent perturbation is necessary to reproduce the observations. Such an impact may have strongly perturbed the existing bar or even triggered its formation in the last 1–2 Gyr

The Institution of Engineering and Technology

Abstract: In a debate paper, Keel and Bhattacharyya have suggested, by means of simple examples taken from the open literature, that optimal and robust controllers can be fragile in the sense that a minute perturbation in the controller parameters can make the closed-loop system unstable. However, is it true that the optimal and robust controllers presented by Keel and Bhattacharyya are actually fragile? It is demonstrated that the particular parametric stability margin used by Keel and Bhattacharyya can be very conservative and to overcome this problem, two non-conservative measures of controller fragility are proposed. In addition, it will be shown that the examples in Keel and Bhattacharyya&apos;s paper are very special and the resulting fragility cannot be linked to the H 1 optimisation but to non-appropriate H 1 optimisation criterions and to bad choice of weights. Introduction In . Different explanations for the fragility problem can be found in the literature. Mäkilä [4] examine Examples 3, 4 and 5 of [1] and present a procedure for assessing the fragility on the basis of the inherent robustness of the closed-loop system to perturbation in the physical parameters that make up implementation, using first-and second-order active RC filters in the implementation of continuous-time controllers and considering the effects of floating point erros in the implementation of digital controllers. More recently, Examples 1 and 2 of [1] have been revisited In spite of all the works listed in the previous paragraph, some questions still remain to be answered. Is it true that the optimal and robust controllers presented in [1] are actually so fragile? More importantly, is it true that the controllers obtained as solutions of the simple optimisation criteria presented in [1] are necessarily fragile? In this paper, these questions are answered and it is demonstrated that the particular stability margin used by Keel and Bhattacharyya can be very conservative and to overcome this problem, two non-conservative measures, based on necessary and sufficient conditions, are proposed here. In addition, it will be shown that the examples presented in [1] are very special and the resulting fragility cannot be associated with H 1 optimisation but to non-appropriate H 1 optimisation criterions and to bad choice of weights. This paper is organised as follows: in section 2, the relative parametric stability margin is reviewed, and an example that suggests the conservativeness of this measure is presented. In section 3, two nonconservative measures of controller fragility are proposed and a comparison between the relative parametric stability margin and the two nonconservative measures introduced in this paper is drawn. In section 4, the examples used in [1] to label H 1 controllers as fragile are re-examined. Finally, conclusions are drawn in section 5. 2 Relative parametric stability margin Definition Consider a closed-loop system with unit negative feedback, wher

[Regula]

Ms. misceláneoCopia digital. Madrid : Ministerio de Cultura. Subdirección General de Coordinación Bibliotecaria, 2006Procede de la desamortización del Monasterio cisterciense de Santa María de Huerta (Soria)"De vita comtemplativa" es de Julianus Pomerius y no de Próspero de Aquitania a quien fue atribuidaCuadernos de 8 h.; pautado a lápiz; caja de escr.: 25 x 16 cm; reclamos; restos de signaturas; foliación posterior a lápiz; iniciales rojas y verdesLas obras de San Basilio ocupan de h. 1r.-40r. (Regula) y de h. 40r.-52v. (Admonitiones); de 52v.-98v. (De vita contemplativa); de Próspero de Aquitania de 99r.-120v. (Contra collationem); los fragmentos de la Etimologías de San Isidoro ocupan de h. 121r.-124r