442 research outputs found

    Galaxy emission line classification using 3D line ratio diagrams

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    Two-dimensional (2D) line ratio diagnostic diagrams have become a key tool in understanding the excitation mechanisms of galaxies. The curves used to separate the different regions - HII-like or else excited by an active galactic nucleus (AGN) - have been refined over time but the core technique has not evolved significantly. However, the classification of galaxies based on their emission line ratios really is a multi-dimensional problem. Here we exploit recent software developments to explore the potential of three-dimensional (3D) line ratio diagnostic diagrams. We introduce a specific set of 3D diagrams, the ZQE diagrams, which separate the oxygen abundance and the ionisation parameter of HII region-like spectra, and which also enable us to probe the excitation mechanism of the gas. By examining these new 3D spaces interactively, we define a new set of 2D diagnostics, the ZE diagnostics, which can provide the metallicity of objects excited by hot young stars, and which cleanly separate HII region-like objects from the different classes of AGNs. We show that these ZE diagnostics are consistent with the key log[NII]/Hα\alpha vs. log[OIII]/Hβ\beta diagnostic currently used by the community. They also have the advantage of attaching a probability that a given object belongs to one class or to the other. Finally, we discuss briefly why ZQE diagrams can provide a new way to differentiate and study the different classes of AGNs in anticipation of a dedicated follow-up study.Comment: 21 pages, 15 figures, accepted for publication in ApJ. Due to size limitations, the supplementary STL file for the 3D-printable diagram is available here: http://www.mso.anu.edu.au/~fvogt/online_material.htm

    Propositional calculus for adjointness lattices

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    Recently, Morsi has developed a complete syntax for the class of all adjointness algebras (L,,A,K,H)\left( L,\leq ,A,K,H\right) . There, (L,)\left( L,\leq \right) is a partially ordered set with top element 11, KK is a conjunction on (L,)\left( L,\leq \right) for which 11 is a left identity element, and the two implication-like binary operations AA and HH on LL are adjoints of KK. In this paper, we extend that formal system to one for the class ADJLADJL of all 9-tuples (L,,1,0,A,K,H,,)\left( L,\leq ,1,0,A,K,H,\wedge ,\vee \right) , called \emph{% adjointness lattices}; in each of which (L,,1,0,,)\left( L,\leq ,1,0,\wedge ,\vee \right) is a bounded lattice, and (L,,A,K,H)\left( L,\leq ,A,K,H\right) is an adjointness algebra. We call it \emph{Propositional Calculus for Adjointness Lattices}, abbreviated AdjLPCAdjLPC. Our axiom scheme for AdjLPCAdjLPC features four inference rules and thirteen axioms. We deduce enough theorems and inferences in AdjLPCAdjLPC to establish its completeness for ADJLADJL; by means of a quotient-algebra structure (a Lindenbaum type of algebra). We study two negation-like unary operations in an adjointness lattice, defined by means of 00 together with AA and HH. We end by developing complete syntax for all adjointness lattices whose implications are SS-type implications

    Management of root rot and wilt diseases of date palm offshoots using certain biological control agents and its effect on growth parameters in the New Valley Governorate, Egypt

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    Root Rot and wilt diseases were observed on different date palm offshoots in nurseries and new orchards in New Valley Governorate, Egypt. Pathogenicity tests showed that Fusarium oxysporum, F. solani and F. moniliforme were the causal agents of root rot and wilt diseases on date palm offshoots (cv. Saidy). In addition, the isolates of the three Fusarium spp. differed in their pathogenic capabilities. The effect of Bacillus subtilis (BSM1), B. megaterium (BMM5), B. cereus (BCM8), Trichoderma viride (TVM2), T. harzianum (THM4) as bioagents against root rot/wilt disease complex of date palm offshoots under natural infection in nursery cultivated in two location (Al-Kharga and El-Dakhla) and also, on growth of the tested pathogenic fungi under laboratory were evaluated. Under laboratory conditions, all the tested bioagents inhibited the growth of the pathogenic fungi with different percentages. Bacillus megaterium and B. subtilis showed the highest percentage of fungal growth inhibition, while T. harzianum gave the lowest ones. At the field level, the application of bioagents significantly reduced the disease severity compared with untreated offshoots (control) in both locations. Bacillus megaterium and T. viride showed the highest protection against fungal causal agents, while B. cereus and T. harzianum gave the lowest ones in this respect. Moreover, the bioagents significantly improved the growth parameters of offshoots viz. plant height, number of leaves plant-1, leaflet number leaf-1, and leaf thickness. Bacillus megaterium and T. viride recorded the highest values of all growth parameters in El-Kharga and El-Dakhla locations, while B. cereus and T. harzianum gave the lowest ones.

    Simulating Piano Performance Mistakes for Music Learning

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    The development of machine-learning based technologies to support music instrument learning needs large-scale datasets that capture the different stages of learning in a manner that is both realistic and computation-friendly. We are interested in modeling the mistakes of beginnerintermediate piano performances in practice or work-inprogress settings. In the absence of large-scale data representing our target case, our approach is to start by understanding such mistakes from real data and then provide a methodology for their simulation, thus creating synthetic data to support the training of performance assessment models. The main goals of this paper are: a) to propose a taxonomy of performance mistakes, specifically apt for simulating or reproducing/recreating them on mistake-free MIDI performances, and b) to provide a pipeline for creating synthetic datasets based on the former. We incorporate prior research in related contexts to facilitate the understanding of common mistake behaviours. Then, we design a hierarchical mistake taxonomy to categorize two real-world datasets capturing relevant piano performance contexts. Finally, we discuss our approach with 3 music teachers through a listening test and subsequent discussions

    Efecto hepatoprotector del insaponificable de los aceites de oliva, linaza y sésamo contra la lesión hepática inducida por tetracloruro de carbono en ratas

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    In the present study, the hepatoprotective activity of the unsaponifiable matter (UNSAP) of olive oil, linseed, and sesame oils against CCl4-induced liver toxicity in rats was investigated. In a preliminary antioxidant study, UNSAP showed pronounced DPPH radical scavenging activity (IC50 6.2-10.8 mg/mL). The constituents of UNSAP were determined by GC-MS. The subcutaneous administration of CCl4, caused liver injury. The hepatoprotective effect of UNSAP was comparable to that of α-tocopherol, a standard antioxidant agent. The co-administration of the investigated UNSAP normalized the activities of serum marker enzymes, alanine aminotransferase (ALT), and aspartate aminotransferase (AST). Furthermore, the serum alkaline phosphatase (ALP) activity and hepatic malondialdehyde (MDA) level were found to be alleviated by pre-treatment with the UNSAP. A histopathological evaluation showed marked improvement in the liver of UNSAP- and α-Tocopherol-treated animals. The hepatoprotective effect could be attributed to the antioxidant characteristics of UNSAP.En el presente estudio, se investigó la actividad hepatoprotectora de la materia insaponificable (UNSAP) de los aceites de oliva, linaza y sésamo contra la toxicidad hepática inducida por CCl4 en ratas. En un estudio preliminar de antioxidantes, UNSAP mostró una pronunciada actividad de captación de radicales DPPH (IC50 6.2-10.8 mg / mL). Los constituyentes del UNSAP fueron determinados por GC-MS. La administración de CCl4, por vía subcutánea, causó lesión hepática. El efecto hepatoprotector del UNSAP fue comparable al del α-Tocoferol, un agente antioxidante estándar. La administración conjunta del UNSAP normalizó las actividades de las enzimas marcadoras séricas, alanina aminotransferasa (ALT) y aspartato aminotransferasa (AST). Además, se encontró que la actividad de la fosfatasa alcalina en suero (ALP) y el nivel de malondialdehído hepático (MDA) se mitigan con el tratamiento previo con UNSAP. La evaluación histopatológica mostró una mejoría notable en el hígado de los animales tratados con UNSAP y α-Tocopherol. El efecto hepatoprotector podría atribuirse a las características antioxidantes de UNSAP

    DA495 - an aging pulsar wind nebula

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    We present a radio continuum study of the pulsar wind nebula (PWN) DA 495 (G65.7+1.2), including images of total intensity and linear polarization from 408 to 10550 MHz based on the Canadian Galactic Plane Survey and observations with the Effelsberg 100-m Radio Telescope. Removal of flux density contributions from a superimposed \ion{H}{2} region and from compact extragalactic sources reveals a break in the spectrum of DA 495 at 1.3 GHz, with a spectral index α=0.45±0.20{\alpha}={-0.45 \pm 0.20} below the break and α=0.87±0.10{\alpha}={-0.87 \pm 0.10} above it (Sννα{S}_\nu \propto{\nu^{\alpha}}). The spectral break is more than three times lower in frequency than the lowest break detected in any other PWN. The break in the spectrum is likely the result of synchrotron cooling, and DA 495, at an age of \sim20,000 yr, may have evolved from an object similar to the Vela X nebula, with a similarly energetic pulsar. We find a magnetic field of \sim1.3 mG inside the nebula. After correcting for the resulting high internal rotation measure, the magnetic field structure is quite simple, resembling the inner part of a dipole field projected onto the plane of the sky, although a toroidal component is likely also present. The dipole field axis, which should be parallel to the spin axis of the putative pulsar, lies at an angle of {\sim}50\degr east of the North Celestial Pole and is pointing away from us towards the south-west. The upper limit for the radio surface brightness of any shell-type supernova remnant emission around DA 495 is Σ1GHz5.4×1023\Sigma_{1 GHz} \sim 5.4 \times 10^{-23} OAWatt m2^{-2} Hz1^{-1} sr1^{-1} (assuming a radio spectral index of α=0.5\alpha = -0.5), lower than the faintest shell-type remnant known to date.Comment: 25 pages, accepted by Ap

    Aeolian transport layer

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    We investigate the airborne transport of particles on a granular surface by the saltation mechanism through numerical simulation of particle motion coupled with turbulent flow. We determine the saturated flux qsq_{s} and show that its behavior is consistent with a classical empirical relation obtained from wind tunnel measurements. Our results also allow to propose a new relation valid for small fluxes, namely, qs=a(uut)αq_{s}=a(u_{*}-u_{t})^{\alpha}, where uu_{*} and utu_{t} are the shear and threshold velocities of the wind, respectively, and the scaling exponent is α2\alpha \approx 2. We obtain an expression for the velocity profile of the wind distorted by the particle motion and present a dynamical scaling relation. We also find a novel expression for the dependence of the height of the saltation layer as function of the wind velocity.Comment: 4 pages, 4 figure

    Chandra Observations of G11.2-0.3: Implications for Pulsar Ages

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    We present Chandra X-ray Observatory imaging observations of the young Galactic supernova remnant G11.2-0.3. The image shows that the previously known young 65-ms X-ray pulsar is at position (J2000) RA 18h 11m 29.22s, DEC -19o 25' 27.''6, with 1 sigma error radius 0.''6. This is within 8'' of the geometric center of the shell. This provides strong confirming evidence that the system is younger, by a factor of ~12, than the characteristic age of the pulsar. The age discrepancy suggests that pulsar characteristic ages can be poor age estimators for young pulsars. Assuming conventional spin down with constant magnetic field and braking index, the most likely explanation for the age discrepancy in G11.2-0.3 is that the pulsar was born with a spin period of ~62 ms. The Chandra image also reveals, for the first time, the morphology of the pulsar wind nebula. The elongated hard-X-ray structure can be interpreted as either a jet or a Crab-like torus seen edge on. This adds to the growing list of highly aspherical pulsar wind nebulae and argues that such structures are common around young pulsars.Comment: 16 pages, 3 figures, Accepted for publication in ApJ. For a full resolution version of Fig 1, see http://www.physics.mcgill.ca/~vkaspi/G11.2-0.3/f1.ep

    Actividades antioxidantes, antiinflamatorias y citotóxicas de la fracción insaponificable de aceite de oliva virgen extra

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    The health benefits of olive oil are well-known. In this study, the unsaponifiable fraction of extra virgin olive oil (Unsap) was investigated for reducing power capacity, ferric reducing antioxidant power, fer-rous chelating activity and nitric oxide inhibition. The present study was also designed to evaluate the in vitro cytotoxic effect of the Unsap against human carcinoma cells. The anti-inflammatory potential of Unsap has been determined via the inhibition of Human Cyclooxygenases. The results showed that Unsap is efficient for ferric reducing antioxidant power and nitric oxide inhibition. Unsap has a selective effect as anti-inflammatory agent. The results showed moderate to good in vitro antitumor activities of Unsap against human liver, lung and pancreas cancer cells with IC50 ranging from 19.6 to 30.4 μg/mL and good selectivity index (≥ 2). In conclusion, Unsap represents a promising and safe antitumor and antioxidant material that supports the need for further investigation.Los beneficios para la salud del aceite de oliva son bien conocidos. En este estudio, se investigó la fracción insaponificable del aceite de oliva virgen extra (Insap) para reducir el poder antioxidante férrico, la actividad quelante ferrosa y la inhibición del óxido nítrico. El presente estudio también fue diseñado para evaluar el efecto citotóxico in vitro del Insap contra las células de carcinoma humano. La potencialidad antiinflamatoria del Insap se ha determinado mediante la inhibición de las ciclooxigenasas humanas. Los resultados mostraron que el Insap es eficiente para reducir el poder antioxidante férrico y la inhibición del óxido nítrico. El Insap tiene un efecto selectivo como agente antiinflamatorio. Los resultados mostraron actividades antitumorales in vitro del Insap de moderadas a buenas contra células de cáncer de hígado, pulmón y páncreas humano con una CI50 que varía de 19,6 a 30,4 μg/ml y por su buen índice de selectividad ( ≥ 2). En conclusión, el Insap contiene material antitumoral y antioxidante prometedor y seguro que será respaldado por investiga-ciones adicionales
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