1,213 research outputs found
On a connection between supernova occurrence and tidal interaction in early type galaxies
There are three types of supernovae: two subtypes SNIa and Ib; and SNII. Late type galaxies produce all types of SN, whereas early types (E, SO, and non-Magellanic irregulars IO) have hosted only SNIa. The recently identified SNIb, like SNII, have massive stars as their progenitors. Reviving Oemler and Tinsley's (1979) suggestion that SNIa also come from short-lived stars, the author asserts that they need not occur in all early-type galaxies. SNIa occur only in those galaxies that have access to gas and can form stars in their main body. (SN in nuclear regions are a different matter altogether). In this model, SNIa are not associated with typical stellar population of E/SOs but with regions of localized star formation. Note that data on SNIa from spirals is already consistent with this model
The RSZ BASIC programming language manual
The RSZ BASIC interactive language is described. The RSZ BASIC interpreter is resident in the Telemetry Data Processor, a system dedicated to the processing and displaying of PCM telemetry data. A series of working examples teaches the fundamentals of RSZ BASIC and shows how to construct, edit, and manage storage of programs
Why Are Radio-Galaxies Prolific Producers of Type Ia Supernovae?
An analysis of SNIa events in early type galaxies from the Cappellaro et al
(1999) database provides conclusive evidence that the rate of type Ia
Supernovae (SNe) in radio-loud galaxies is about 4 times higher than the rate
measured in radio-quiet galaxies, i.e. SNIa-rate SNu as compared to SNIa-rate SNu. The actual value of the
enhancement is likely to be in the range (P). This
finding puts on robust empirical grounds the results obtained by Della Valle &
Panagia (2003) on the basis of a smaller sample of SNe. We analyse the possible
causes of this result and conclude that the enhancement of SNIa explosion rate
in radio-loud galaxies has the same origin as their being strong radio sources,
but there is no causality link between the two phenomena. We argue that
repeated episodes of interaction and/or mergers of early type galaxies with
dwarf companions, on times-scale of about 1 Gyr, are responsible for inducing
both strong radio activity observed in 14% of early type galaxies and to
supply an adequate number of SNIa progenitors to the stellar population of
ellipticals.Comment: 26 pages+6 figures, ApJ, in pres
Study of the Efficacy of Malathion Impregnated Cotton Cords in Housefly Control
A comparative study on the efficacy of malathion impregnated cords on 13 mm and 22 mm circumference in housefly control has been carried. The results have shown that 13 mm cord is more economical weight for weight, but both afford protection from four to five months. Other factors like temperature and humidity which influence the efficacy of cords are discussed
«Security» in industrial frying processes.
. It is well known that equipment design features can have a profound effect on the working life of a frying oil, and consequently on secure/safe operation of the industrial deep-frying at high temperatures. The design aspects of the cooker should eliminate known factors of heat degradation/oxidation in the frying oil while maintaining outputs of products of consistent quality. For instance, the pro-oxidant catalyst copper or brass valves/fittings must not be employed. Continuous removal of debris/sediment and the maintenance of uniform oil temperatures leads to the development of FFAs at a lower rate, better taste, colour and appearance of the product. Security thermostats are fitted to each heating element in many modern, small-scale catering fryers. These are designed to trip out if the primary thermostat fails to function. Also the current isolation switch cuts off the electrical supply if the element head is not placed correctly in the fryer. In both catering and industrial frying operations, smoke haze can be a problem. The volatile break-down products such as FFAs, etc. formed in the oil being heated at high temperatures give rise to smoke, which if not controlled can enhance fire hazards due to their lower flash point. The smoke point is of most benefit in assessing the quality of a frying oil, since it is mainly the FFAs produced in the frying operation which contribute to the smoke haze. Commercial frying oils as well as the entire frying installation including cooker design, must meet strict quality and safety requirements. These features become extremely important, especially in the industrial flash frying operation when the frying oil is heated to a higher temperature of 200°G. High oil quality and high smoke/flash point frying oils are essential characteristics of the flash frying operation. These days, two important features namely carbon dioxide blanketing system and a waste air cleaning system have become standard design items for secure and environmental friendly operation of multi-purpose industrial fryers. This paper will highlight various safety and design features of many modern, industrial frying operations
The rate and the origin of type Ia supernovae in radiogalaxies
An analysis of type Ia supernova (SNIa) events in early type galaxies from
Evans et al (1989) database provides strong evidence that the rate of type Ia
supernovae (SNe) in radio-loud galaxies is about 6 times higher than the rate
measured in radio-quiet galaxies, i.e. SNIa-rate SNe per century and per
10L (SNU) as compared to SNIa-rate(radio-quiet
galaxies)\lsim 0.080 h^2_{50} SNU. The exact value of the enhancement is still
rather uncertain, but is likely to be in the range . We discuss the
possible causes of this result and we conclude that that the enhancement of
SNIa explosion rate in radio-loud galaxies has the same common origin as their
being strong radio sources, but that there is no causality link between the two
phenomena. We argue that repeated episodes of interaction and/or mergers of
early type galaxies with dwarf companions are responsible for inducing both
strong radio activity in 14% of early type galaxies, and the Gyr
old stellar population needed to supply an adequate number SNIa progenitors.
Within this scenario we predict that the probability of detecting a
core-collapse SN event in radio-loud elliptical galaxies amounts to about 4% of
their SNIa events.Comment: 17 pages, 1 figure, accepted for publication in ApJ
Reliability and Reproducibility of Landmark Identification in Unilateral Cleft Lip and Palate Patients: Digital Lateral Vis-A-Vis CBCT-Derived 3D Cephalograms
Background: The aim of the retrospective observational study was to compare the precision of landmark identification and its reproducibility using cone beam computed tomography-derived 3D cephalograms and digital lateral cephalograms in unilateral cleft lip and palate patients. Methods: Cephalograms of thirty-one (31) North Indian children (18 boys and 13 girls) with a unilateral cleft lip and palate, who were recommended for orthodontic treatment, were selected. After a thorough analysis of peer-reviewed articles, 20 difficult-to-trace landmarks were selected, and their reliability and reproducibility were studied. These were subjected to landmark identification to evaluate interobserver variability; the coordinates for each point were traced separately by three different orthodontists (OBA, OBB, OBC). Statistical analysis was performed using descriptive and inferential statistics with paired t-tests to compare the differences measured by the two methods. Real-scale data are presented in mean ± SD. A p-value less than 0.05 was considered as significant at a 95% confidence level. Results: When comparing, the plotting of points posterior nasal spine (PNS) (p < 0.05), anterior nasal spine (ANS) (p < 0.01), upper 1 root tip (p < 0.05), lower 1 root tip (p < 0.05), malare (p < 0.05), pyriforme (p < 0.05), porion (p < 0.01), and basion (p < 0.05) was statistically significant. Conclusion: In patients with a cleft lip and palate, the interobserver identification of cephalometric landmarks was significantly more precise and reproducible with cone beam computed tomography -derived cephalograms vis-a-vis digital lateral cephalograms
Effects of Single versus Multiple Warnings on Driver Performance
Objective: To explore how a single master alarm system affects drivers’ responses when compared to multiple, distinct warnings. Background: Advanced driver warning systems are intended to improve safety, yet inappropriate integration may increase the complexity of driving, especially in high workload situations. This study investigated the effects of auditory alarm scheme, reliability, and collision event-type on driver performance. Method: A 2x2x4 mixed factorial design investigated the impact of two alarm schemes (master vs. individual) and two levels of alarm reliability (high and low) on distracted drivers’ performance across four collision event-types (frontal collision warnings, left and right lane departure warnings, and follow vehicle fast approach). Results: Participants’ reaction times and accuracy rates were significantly affected by the type of collision event and alarm reliability. The use of individual alarms, rather than a single master alarm, did not significantly affect driving performance in terms of reaction time or response accuracy. Conclusion: Even though a master alarm is a relatively uninformative warning, it produced statistically no different reaction times or accuracy results when compared to information-rich auditory icons, some of which were spatially located. In addition, unreliable alarms negatively impacted driver performance, regardless of event type or alarm scheme.
Application: These results have important implications for the development and implementation of multiple driver warning systems.This project was sponsored by the Ford Motor Company
Endoscopic Nasobiliary Drainage in the Management of Acute Cholangitis: An Experience in 143 Patients
Acute cholangitis is associated with a high mortality and morbidity and often requires
drainage of the obstructed biliary system. The purpose of this study was to evaluate the
usefulness and safety of endoscopic nasobiliary drainage in the treatment and prevention
of acute cholangitis due to diverse etiology. During a 32-month period, 143 patients
(67 males, 76 females) with age range of 15 to 84 years underwent urgent fluoroscopy
guided endoscopic nasobiliary drainage using a 7 Fr catheter either to treat acute
cholangitis not responding to antibiotics (group A, n = 116) or to prevent its development
following endoscopic retrograde cholangiography performed in an obstructed biliary
system (group B, n = 27). Underlying etiology included bile duct stones (92), malignant
biliary obstruction (34), choledochal cyst (4), chronic pancreatitis (4), ruptured hydatid
cyst (3), portal hypertensive cholangiopathy (3) and liver abscess (3). Endoscopic
nasobiliary drainage was performed successfully in 129 patients (90.2%). Cholangitis
improved within 1 to 3 days (in group A) or did not develop (in Group B) in 125 patients
(96.7%) with successful endoscopic nasobiliary drainage. Two patients however required
additional drainage by percutaneous transhepatic route, while two died inspite of effective
endoscopic drainage. Of the 14 patients (9.8%) with failed endoscopic drainage, 9 were
managed by surgical decompression or percutaneous transhepatic drainage, 3 died of
septicemia. Endoscopic nasobiliary drainage is a safe and effective method to treat
patients with acute cholangitis as well as to prevent its development following
cholangiography performed in an obstructed biliary system
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