7,401 research outputs found

    A catalog of planetary nebulae in the elliptical galaxy NGC 4697

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    We present a catalog of 535 planetary nebulae discovered in the flattened elliptical galaxy NGC 4697, using the FORS1 Cassegrain spectrograph of the Very Large Telescope of the European Southern Observatory at Cerro Paranal, Chile. The catalog provides positions (x, y coordinates relative to the center of light of NGC 4697, as well as RA, Dec.), and, for almost all PNs, the magnitude m(5007) and the heliocentric radial velocity in km/s.Comment: 16 pages, 5 figures, ApJS in pres

    Planetary nebulae in the elliptical galaxy NGC 821: kinematics and distance determination

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    Using a slitless spectroscopy method with the 8.2 m Subaru telescope and its FOCAS Cassegrain spectrograph, we have increased the number of planetary nebula (PN) detections and PN velocity measurements in the flattened elliptical galaxy NGC 821. A comparison with the detections reported previously by the Planetary Nebula Spectrograph (PN.S) group indicates that we have confirmed most of their detections. The velocities measured by the two groups, using different telescopes, spectrographs and slitless techniques, are in good agreement. We have built a combined sample of 167 PNs and have confirmed the keplerian decline of the line-of-sight velocity dispersion reported previously. We also confirm misaligned rotation from the combined sample. A dark matter halo may exist around this galaxy, but it is not needed to keep the PN velocities below the local escape velocity as calculated from the visible mass. We have measured the m(5007) magnitudes of 145 PNs and produced a statistically complete sample of 40 PNs in NGC 821. The resulting PN luminosity function (PNLF) was used to estimate a distance modulus of 31.4 mag, equivalent to 19 Mpc. We also estimated the PN formation rate. NGC 821 becomes the most distant galaxy with a PNLF distance determination. The PNLF distance modulus is smaller than the surface brightness fluctuation (SBF) distance modulus by 0.4 mag. Our kinematic information permits to rule out the idea that a shorter PNLF distance could be produced by the contamination of the PNLF by background galaxies with emission lines redshifted into the on-band filter transmission curve.Comment: Accepted for publication in ApJ; 16 figure

    Delayed identification and diagnosis of Huntington\u27s disease due to psychiatric symptoms

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    Huntington\u27s disease (HD) is a progressive neurodegenerative illness that affects 2-9/100.000 of the general population. The usual onset is at around age 35-40 years, but there were cases with onset above 55 years. The disease manifests clinically with many neurological and psychiatric symptoms, leading in advanced phases to dementia, but cognitive symptoms are frequently present much earlier in the disease course. HD is caused by an expanded polyglutamine stretch in the N-terminal part of a 350 kDa protein called huntingtin (HTT). This stretch is encoded by a trinucleotide CAG repetition in exon 1 of HTT. An expansion of greater than 36 repeats results in HD. The number of repeats is inversely correlated with the age of onset of motor symptoms, and disease onset during childhood or adolescence is associated with more than 60 CAG repeats. Mood disturbances may be one of the earliest symptoms of HD and may precede the onset of the motor pheno-type for almost 10 years. Neuropsychiatric symptoms may delay the appropriate diagnosis of HD and have major implications for disease management, prognosis and quality of life for patients and families. This case study is about a 58 years old female patient with late identification of Huntington\u27s disease after two admissions to psychiatric inpatient units, for the treatment of behavioral disturbances

    Planetary nebulae and stellar kinematics in the flattened elliptical galaxy NGC 1344

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    We present photometric and kinematic information obtained by measuring 197 planetary nebulae (PNs) discovered in the flattened Fornax elliptical galaxy NGC 1344 (also known as NGC 1340) with an on-band, off-band, grism + on-band filter technique. We build the PN luminosity function (PNLF) and use it to derive a distance modulus m-M=31.4, slightly smaller than, but in good agreement with, the surface brightness fluctuation distance. The PNLF also provides an estimate of the specific PN formation rate: 6x10^-12 PNs per year per solar luminosity. Combining the positional information from the on-band image with PN positions measured on the grism + on-band image, we can measure the radial velocities of 195 PNs, some of them distant more than 3 effective radii from the center of NGC 1344. We complement this data set with stellar kinematics derived from integrated spectra along the major and minor axes, and parallel to the major axis of NGC 1344. The line-of-sight velocity dispersion profile indicates the presence of a dark matter halo around this galaxy.Comment: 45 pages, 18 figures, accepted for publication in Ap

    Generic critical points of normal matrix ensembles

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    The evolution of the degenerate complex curve associated with the ensemble at a generic critical point is related to the finite time singularities of Laplacian Growth. It is shown that the scaling behavior at a critical point of singular geometry x3∌y2x^3 \sim y^2 is described by the first Painlev\'e transcendent. The regularization of the curve resulting from discretization is discussed.Comment: Based on a talk given at the conference on Random Matrices, Random Processes and Integrable Systems, CRM Montreal, June 200

    STEADY-STATE POWER FLOW CALCULATION IN A HYBRID HVAC/VSC-HVDC GRID

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    Voltage source converter high voltage direct current (VSC-HVDC) transmission technology is increasing its share in AC transmission due to important advantages such as independent P and Q control and lower harmonics. Nowadays, this technology is used to connect far-away remote offshore wind-power plants to mainland networks. VSC-HVDC is the main actor in developing the future multi-terminal DC grids and supergrids. This paper proposes a sequential algorithm to calculate the steady state power flow in a specific hybrid HVAC/VSC-HVDC grid which is a solution that is going to be seen in the early stages of the planned supergid

    A comparative study of heating elements used for the development of textile heaters

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    The focus of this paper is to make a comparison between five different types of conductive, heatable samples. These textile samples have been produced according to the five most important implementation techniques such as knitting, weaving, embroidery, printing and nonwoven padding. The idea is to identify a conductive option best suitable for a heating application. This study was divided into four major steps: choosing the adequate materials, swatch production, conductivity measurements and heating behaviour assessment. The first three methods use electro conductive wires as heating elements, the fourth uses conductive ink and the fifth uses carbon black coating. For all of them, resistance, current and heat distribution was measured. The results show that the best options for the development of a wearable textile heating system are the embroidered and the woven techniques, as their mechanical strength and elasticity, is sufficiently high and the fabric/substrate structure allows the insertion/deposition of different types of heating element

    The effects of meson mixing on dilepton spectra

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    The effect of scalar and vector meson mixing on the dilepton radiation from hot and dense hadronic matter is estimated in different isospin channels. In particular, we study the effect of σ\sigma-ω\omega and ρ−a0\rho-a_0 mixing and calculate the corresponding rates. Effects are found to be significant compared to standard π\pi-π\pi and KK-Kˉ{\bar K} annihilations. While the mixing in the isoscalar channel mostly gives a contribution in the invariant mass range between the two-pion threshold and the ω\omega peak, the isovector channel mixing induces an additional peak just below that of the ϕ\phi. Experimentally, the dilepton signals from ρ\rho-a0a_0 mixing seem to be more tractable than those from σ\sigma-ω\omega mixing.Comment: 10 pages, 9 figure

    Multipartite entanglement in 2 x 2 x n quantum systems

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    We classify multipartite entangled states in the 2 x 2 x n (n >= 4) quantum system, for example the 4-qubit system distributed over 3 parties, under local filtering operations. We show that there exist nine essentially different classes of states, and they give rise to a five-graded partially ordered structure, including the celebrated Greenberger-Horne-Zeilinger (GHZ) and W classes of 3 qubits. In particular, all 2 x 2 x n-states can be deterministically prepared from one maximally entangled state, and some applications like entanglement swapping are discussed.Comment: 9 pages, 3 eps figure
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