697 research outputs found
A detailed systematic anatomical study of monocephalic conjoined symmetric twin lambs
A case of conjoined twins with monocephalus, thoracopagus, partial abdominopagus, tetrabrachius and tetrascelus in lambs complicated with several defects of skeletal, cardiovascular, gastrointestinal, and urogenital systems is reported. The twins were dead and delivered by cesarean section. This case report highlights the detailed anatomical study of defects in different systems due to an abnormal birth defect.Keywords: Monocephalus, Sheep, Tetrabrachius, Tetrascelus, Thoracopagu
Calibration and accuracy determination of airdata system for a modern fighter
An Air data system (ADS) is an essential avionics module found in modern fighter
aircraft cockpits. It provides critical information about the aircraft to the pilot throughout
the flight regime. Airdata system comprises of air data computer and their associated
sensors. Sensors instrumented on aircraft normally measure pressures and flow angles in the
local flow field using vanes and probes. However, aircraft requires the free stream
parameters for flying. Therefore, forward lookup tables in Air Data Computer (ADC) are
used to covert local parameters measured using airdata sensor to free stream parameters. In
order to design flight controls, improved system performance, ADS should deliver accurate
output. Accuracy of free stream parameters depends upon the accuracy of these tables in Air
data computer. In this paper, the airdata system of a modern fighter aircraft is considered.
This system carries airdata tables which are calibrated/updated using Maximum Likelihood
Estimation (MLE) method. The accuracy of it needs to be determined by another
independent technique. Hence an Extended Kalman Filter (EKF) is proposed to calibrate
and describe the accuracy limits of airdata system. The technique is tested with flight data
and the results demonstrate the strength of the technique for airdata calibration and
accuracy determination
The architecture of the middle ear in the small Indian mongoose (Herpestes Javanicus)
The small Indian mongoose (Herpestes javanicus) is native to the Middle East, Iran and much of southern Asia. For this study the middle ears of a total of 6 adult small Indian mongooses, both fresh and museum samples were explored by using of dissection and plain radiography. On the one hand, at least in some species of the mongoose vocalisations and hearings play a critical role in coordinating behaviours. On the other hand, the ear region has provided useful character relevant for mammalian phylogeny. So, the aim of the present study is a brief discussion of the various anatomic particularities of the middle ear based on a combination of existing data and the results of the authors’ study in the small Indian mongoose
Radio continuum of galaxies with HO megamaser disks: 33 GHz VLA data
We investigate the nuclear environment of galaxies with observed 22 GHz water
megamaser in their subparsec edge-on accretion disks, using 33 GHz (9mm) radio
continuum data from VLA, with a resolution of ~ 0.2-0.5 arcsecs, and relate the
maser and host galaxy properties to those of its radio continuum emission.
Eighty-seven percent (21 out of 24) galaxies in our sample show 33 GHz radio
continuum emission at levels of 4.5-240 . Five sources show extended
emission, including one source with two main components and one with three main
components. The remaining detected 16 sources exhibit compact cores within the
sensitivity limits. Little evidence is found for extended jets (>300 pc) in
most sources. Either they do not exist, or our chosen frequency of 33 GHz is
too high for a detection of these supposedly steep spectrum features. In only
one source among those with known maser disk orientation, NGC4388, we found an
extended jet-like feature that appears to be oriented perpendicular to the
water megamaser disk. Smaller 100-300 pc sized jets might also be present, as
is suggested by the beam-deconvolved morphology of our sources. Whenever
possible, central positions with accuracies of 20-280 mas are provided. A
correlation analysis shows that the 33 GHz luminosity weakly correlates with
the infrared luminosity. The 33 GHz luminosity is anticorrelated with the
circular velocity of the galaxy. The black hole masses show stronger
correlations with water maser luminosity than with 1.4 GHz, 33 GHz, or hard
X-ray luminosities. Furthermore, the inner radii of the disks show stronger
correlations with 1.4 GHz, 33 GHz, and hard X-ray luminosities than their outer
radii, suggesting that the outer radii may be affected by disk warping, star
formation, or peculiar density distributions.Comment: 18 pages, 10 figures, Accepted for publication in A&
The Persian developmental sentence scoring as a clinical measure of morphosyntax in children
Background: Developmental Sentence Scoring (DSS) was developed as a numerical measurement and a clinical method based on the morphosyntactic acquisition in the English language. The aim of this study was to develop a new numerical tool similar to DSS to assess the morphosyntactic abilities in Persian-speaking children. Methods: In this cross-sectional and comparative study, the language samples of 115 typically developing Persian-speaking children aged 30 - 65 months were audio recorded during the free play and picture description sessions. The Persian Developmental Sentence Score (PDSS) and the Mean Length of Utterance (MLU) were calculated. Pearson correlation and one - way Analysis of variance (ANOVA) were used for data analysis. Results: The correlation between PDSS and MLU in morphemes (convergent validity) was significant with a correlation coefficient of 0.97 (p < 0.001). The value Cronbach's Alpha (α= 0.79) in the grammatical categories and the split-half coefficient (0.86) indicated acceptable internal consistency reliability. Conclusion: The PDSS could be used as a reliable numerical measurement to estimate the syntactic development in Persian-speaking children
First record of Agistemus collyerae (Acari: Stigmaeidae) from Iran
During a survey on stigmaeid mites in northwestern Iran (2004-2006), several specimens of the family Stigmaeidae were collected on olive trees in Moghan (Ardebil province) in July 2006. These mites were later identified as Agistemus collyerae Gonzalez-Rodriguez. This is the first record of this species from Iran. The specimens were collected along with the specimens of the family Eriophyidae on olive leaves demonstrating a type of correlation between stigmaeid and eriophyid mites. Further studies on the ecological roles of these mites will provide better understanding of their coexisting behavior
Population growth parameters of Tetranychus urticae (Acari: Tetranychidae) on different bean varieties
Population growth parameters of Tetranychus urticae Koch on four bean varieties including Talash (Colorado bean), Sadaf (Navy bean), Goli (Kidney bean) and Parastoo (Black-eye bean) were investigated in laboratory conditions at 25 ± 1°C, 60 ± 5% RH and a photoperiod of 16: 8 (L: D) h. In this experiment, one-day old eggs of T. urticae were selected and reared in growth chamber until the death of the last female mite, and the survival rate and female progeny of the mite were measured. Net reproduction rate (R0) on four bean varieties, was 8.822, 3.622, 4.908 and 2.043, intrinsic rate of increase (rm) was 0.142, 0.079, 0.095 and 0.038, and finite rate of increase (λ) was 1.152, 1.082, 1.099 and 1.039, respectively. Mean generation time (T) was determined 15.381, 16.283, 16.715 and 18.308 and doubling time (DT) was 4.901, 8.787, 7.292 and 18.125 days, respectively. The results indicated that the rate of population growth of T. urticae on Talash variety was more than other varieties. The rates of population parameters on Parastoo variety were the least
Life history and population growth parameters of Tyrophagus putrescentiae (Acari: Acaridae) on Fusarium graminearum in laboratory conditions
The life history of an acarid mite, Tyrophagus putrescentiae (Schrank), on Fusarium graminearum Clade was investigated at 25 ± 1°C, 60 ± 5% RH and a photoperiod of 16: 8 (L: D) h. Incubation period for egg hatch, larval and nymphal periods and adult longevity were 2.22 ± 0.06, 3.46 ± 0.12, 4.84 ± 0.16 and 10.05 ± 0.9 days, respectively. The average life span of males and females were 22.22 ± 1.21 and 19.08 ± 1.37 days respectively. Pre-oviposition, oviposition and post-oviposition periods were 2.22, 5.77 and 1.4 days respectively. Gross and net fecundity rates were obtained 76.2 and 23 eggs per female per generation respectively. Net reproduction rate was 12.5 female eggs per female per generation, and average daily oviposition rate was 5.7 eggs. The intrinsic and finite rates of population increase were 0.15 and 1.16 day-1 respectively. The mean generation time (T) and the mean doubling time (DT) were 16.74 and 4.59 days respectively. The population mainly (78%) consisted of eggs and larvae, and nymphs and adults represented only 22% of the population
Tetranychid mites and their natural enemies in Maragheh region and the first record of Neopronematus neglectus (Acari: Iolinidae) from Iran
During 2006 a survey was carried out on tetranychid mites and their natural enemies in Maragheh apple orchards (North-west of Iran). In this survey a total of 20 species within the families Tetranychidae, Phytoseiidae, Stigmaeidae, Anystidae, Iolinidae, Coccinellidae, Chrysopidae and Thripidae were collected and identified. One species of the Iolinidae identified as Neopronematus neglectus (Kuznetzov) and its identity was confirmed by Dr. Edward Ueckermann from Plant Protection Research Institute of South Africa. It is reported here as a new record to Acari fauna of Iran
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