183 research outputs found
Some factors affecting the efficiency of potato production, under Al–Ghab plain conditions, Syrian Arab Republic
ArticleData were collected by a field survey of 300 farmers from Al–Ghab region (Syria)
during 2014–2015. The non–parametric Data Envelopment was used in analyzing the Technical
efficiency. The relationship between farm size and production efficiency was considered.
Technical efficiency amounted about 53% and most of farms are operating at low level of
technical efficiency. The relationship between farm size and productivity efficiency is Non–
linear, it decreases from small to medium farm size and then increases as the size increase. Large
farms have the higher net farm income per thousand square metersand are the most efficient
technically followed by small and medium farm size. To disclose that factors causing the
technical efficiency, Two–limit Tobit Regression Model was used. The calculated results showed
that, Household Size, Occupation, Farm Size, Experience in Farming, Seed Type and
Membership are factors that cause the technical inefficiency potato farming at Al–Ghab region.
Therefore, the Syrian Planning Board and Decision Makers should take this results into account
when they draw their plans to improve farmer's skills by allocating more investment in farm
research and extension programmers
Diagnostics of hydraulic fluids used in aviation
ArticleDiagnostics is a maintenance industry that monitors performance, parameters, and
follow
–
up. Diagnosing hydraulic fluids means comparing the parameters of the used hydr
aulic
fluid sample to the parameters of the clean fluid. It is also essentia
l to monitor the limit values
either by the aircraft manufacturer or by the manufacturer of the hydraulic fluid. This means
that the manufacturer recommends the limitations of the
liquid parameters. The measurements
of the fluid samples give an overview of the liquid quality. Most businesses focus on so
–
called
proactive maintenance. The main senses and objectives of proactive maintenance are: lubricant
sample analysis, lubricant sta
tus, machine status, next step recommendation, database saving
and trend analysis. This article focuses on the quality of hydraulic fluid focused in aviation. The
aim of the article was to determine the properties of the hydraulic fluid used in the A320 ai
rcraft
family, determine the interval of its exchange. Monitoring the state of the hydraulic fluid could
contribute to the timely detection of the problem, thus avoiding a failure of the device or the
system as a
whole. The tracking proposal is an integral
part of this article
A dust-parallax distance of 19 megaparsecs to the supermassive black hole in NGC 4151
The active galaxy NGC 4151 has a crucial role as one of only two active
galactic nuclei for which black hole mass measurements based on emission line
reverberation mapping can be calibrated against other dynamical methods.
Unfortunately, effective calibration requires an accurate distance to NGC 4151,
which is currently not available. Recently reported distances range from 4 to
29 megaparsecs (Mpc). Strong peculiar motions make a redshift-based distance
very uncertain, and the geometry of the galaxy and its nucleus prohibit
accurate measurements using other techniques. Here we report a dust-parallax
distance to NGC 4151 of Mpc. The measurement is
based on an adaptation of a geometric method proposed previously using the
emission line regions of active galaxies. Since this region is too small for
current imaging capabilities, we use instead the ratio of the
physical-to-angular sizes of the more extended hot dust emission as determined
from time-delays and infrared interferometry. This new distance leads to an
approximately 1.4-fold increase in the dynamical black hole mass, implying a
corresponding correction to emission line reverberation masses of black holes
if they are calibrated against the two objects with additional dynamical
masses.Comment: Authors' version of a letter published in Nature (27 November 2014);
8 pages, 5 figures, 1 tabl
Modeling the optical/UV polarization while flying around the tilted outflows of NGC 1068
Recent modeling of multi-waveband spectroscopic and maser observations
suggests that the ionized outflows in the nuclear region of the archetypal
Seyfert-2 galaxy NGC 1068 are inclined with respect to the vertical axis of the
obscuring torus. Based on this suggestion, we build a complex reprocessing
model of NGC 1068 for the optical/UV band. We apply the radiative transfer code
STOKES to compute polarization spectra and images. The effects of electron and
dust scattering and the radiative coupling occurring in the inner regions of
the multi-component object are taken into account and evaluated at different
polar and azimuthal viewing angles. The observed type-1/type-2 polarization
dichotomy of active galactic nuclei is reproduced. At the assumed observer's
inclination toward NGC 1068, the polarization is dominated by scattering in the
polar outflows and therefore it indicates their tilting angle with respect to
the torus axis. While a detailed analysis of our model results is still in
progress, we briefly discuss how they relate to existing polarization
observations of NGC 1068.Comment: To appear in the proceedings of the meeting "The Central Kiloparsec
in Galactic Nuclei" held in Bad Honnef (Germany) from August 29th to
September 2nd 201
Mid-infrared observations of the transitional disks around DH Tau, DM Tau, and GM Aur
Aims: We present mid-infrared observations and photometry of the transitional
disks around the young stellar objects DH Tau, DM Tau, and GM Aur, obtained
with VISIR/VLT in N band. Our aim is to resolve the inner region and the
large-scale structures of these transitional disks, carrying potential
signatures of intermediate or later stages of disk evolution and ongoing planet
formation.
Methods: We use the simultaneously observed standard-stars as PSF reference
to constrain the radial flux profiles of our target objects. Subtracting the
obtained standard-star profile from the corresponding science object profile
yields the flux residuals produced by the star-disk system. A detection
threshold takes into account the background standard deviation and also the
seeing variations during the observations to evaluate the significance of these
flux residuals. On the basis of a simple model for the dust re-emission, we
derive constraints on the inner radius of the dust disk.
Results: We spatially resolve the transitional disk around GM Aur and
determine an inner-disk hole radius of 20.5(+1.0,-0.5) AU. The circumstellar
disks around DH Tau and DM Tau are not spatially resolved but we are able to
constrain the inner-disk hole radius to <15.5(+9.0,-2.0) AU and
<15.5(+0.5,-0.5) AU, respectively. The performed photometry yields fluxes of
178+-31 mJy for DH Tau, 56+-6 mJy for DM Tau, and 229+-14 mJy for GM Aur.Comment: Accepted for publication in Astronomy & Astrophysics. (6 pages,
including 7 figures and 5 tables
Saliva molecular inflammatory profiling in female migraine patients responsive to adjunctive cervical non-invasive vagus nerve stimulation : the MOXY Study
BackgroundRising evidence indicate that oxytocin and IL-1 impact trigemino-nociceptive signaling. Current perspectives on migraine physiopathology emphasize a cytokine bias towards a pro-inflammatory status. The anti-nociceptive impact of oxytocin has been reported in preclinical and human trials. Cervical non-invasive vagus nerve stimulation (nVNS) emerges as an add-on treatment for the preventive and abortive use in migraine. Less is known about its potential to modulate saliva inflammatory signaling in migraine patients. The rationale was to perform inter-ictal saliva measures of oxytocin and IL-1 ss along with headache assessment in migraine patients with 10weeks adjunctive nVNS compared to healthy controls.Methods12 migraineurs and 12 suitably matched healthy control were studied with inter-ictal saliva assay of pro- and anti-neuroinflammatory cytokines using enzyme-linked immuno assay techniques along with assessment of headache severity/frequency and associated functional capacity at baseline and after 10weeks adjunctive cervical nVNS.ResultsnVNS significantly reduced headache severity (VAS), frequency (headache days and total number of attacks) and significantly improved sleep quality compared to baseline (pPeer reviewe
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