442 research outputs found
Galaxy emission line classification using 3D line ratio diagrams
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]/H vs.
log[OIII]/H 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
Recently, Morsi has developed a complete syntax for the class of all
adjointness algebras . There, is a partially ordered set with top element , is a
conjunction on for which is a left identity
element, and the two implication-like binary operations and on
are adjoints of .
In this paper, we extend that formal system to one for the class of
all 9-tuples , called \emph{%
adjointness lattices}; in each of which is a bounded lattice, and is an
adjointness algebra. We call it \emph{Propositional Calculus for Adjointness
Lattices}, abbreviated . Our axiom scheme for features four
inference rules and thirteen axioms. We deduce enough theorems and
inferences in to establish its completeness for ; 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 together with and . We end by developing complete syntax for
all adjointness lattices whose implications are -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
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
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
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
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 below the break and
above it (). 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 20,000 yr, may have
evolved from an object similar to the Vela X nebula, with a similarly energetic
pulsar. We find a magnetic field of 1.3 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 OAWatt
m Hz sr (assuming a radio spectral index of ), lower than the faintest shell-type remnant known to date.Comment: 25 pages, accepted by Ap
Aeolian transport layer
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 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, , where and
are the shear and threshold velocities of the wind, respectively, and
the scaling exponent is . 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
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
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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