23 research outputs found
Train schedule delays leading to overcrowding, injuries and fatalities
Abstract: Rail industry in South Africa is facing a dilemma in connection with trains overcrowding causing injuries and fatalities. This paper emphasized this topic analysis to reach the understanding of the problem to an eventual solution that will benefit both the train user and the operator. One of the priority insights look was at the annual train planned schedule versus the actual state of trains given to run. The overall objective of the paper’s study was to analyze the existing train schedule that is currently in use and whether addressing the needs of the commuter. The paper highlighted that the found-out train planned schedule are not always met due to technical issues. The paper also investigated the number of healthy trains versus the commuter demand per peak, because operationally fit trains are required to avoid service distraction that can lead to overcrowding of trains
Revival of the magnetar PSR J1622-4950: observations with MeerKAT, Parkes, XMM-Newton, Swift, Chandra, and NuSTAR
New radio (MeerKAT and Parkes) and X-ray (XMM-Newton, Swift, Chandra, and
NuSTAR) observations of PSR J1622-4950 indicate that the magnetar, in a
quiescent state since at least early 2015, reactivated between 2017 March 19
and April 5. The radio flux density, while variable, is approximately 100x
larger than during its dormant state. The X-ray flux one month after
reactivation was at least 800x larger than during quiescence, and has been
decaying exponentially on a 111+/-19 day timescale. This high-flux state,
together with a radio-derived rotational ephemeris, enabled for the first time
the detection of X-ray pulsations for this magnetar. At 5%, the 0.3-6 keV
pulsed fraction is comparable to the smallest observed for magnetars. The
overall pulsar geometry inferred from polarized radio emission appears to be
broadly consistent with that determined 6-8 years earlier. However, rotating
vector model fits suggest that we are now seeing radio emission from a
different location in the magnetosphere than previously. This indicates a novel
way in which radio emission from magnetars can differ from that of ordinary
pulsars. The torque on the neutron star is varying rapidly and unsteadily, as
is common for magnetars following outburst, having changed by a factor of 7
within six months of reactivation.Comment: Published in ApJ (2018 April 5); 13 pages, 4 figure
The MeerKAT telescope as a pulsar facility: System verification and early science results from MeerTime
We describe system verification tests and early science results from the pulsar processor (PTUSE) developed for the newly commissioned 64-dish SARAO MeerKAT radio telescope in South Africa. MeerKAT is a high-gain ( ) low-system temperature ( ) radio array that currently operates at 580–1 670 MHz and can produce tied-array beams suitable for pulsar observations. This paper presents results from the MeerTime Large Survey Project and commissioning tests with PTUSE. Highlights include observations of the double pulsar , pulse profiles from 34 millisecond pulsars (MSPs) from a single 2.5-h observation of the Globular cluster Terzan 5, the rotation measure of Ter5O, a 420-sigma giant pulse from the Large Magellanic Cloud pulsar PSR , and nulling identified in the slow pulsar PSR J0633–2015. One of the key design specifications for MeerKAT was absolute timing errors of less than 5 ns using their novel precise time system. Our timing of two bright MSPs confirm that MeerKAT delivers exceptional timing. PSR exhibits a jitter limit of whilst timing of PSR over almost 11 months yields an rms residual of 66 ns with only 4 min integrations. Our results confirm that the MeerKAT is an exceptional pulsar telescope. The array can be split into four separate sub-arrays to time over 1 000 pulsars per day and the future deployment of S-band (1 750–3 500 MHz) receivers will further enhance its capabilities
The SARAO MeerKAT 1.3 GHz Galactic Plane Survey
We present the SARAO MeerKAT Galactic Plane Survey (SMGPS), a 1.3 GHz continuum survey of almost half of the Galactic Plane (251\deg 358\deg and 2\deg 61\deg at ). SMGPS is the largest, most sensitive and highest angular resolution 1 GHz survey of the Plane yet carried out, with an angular resolution of 8" and a broadband RMS sensitivity of 10--20 Jy/beam. Here we describe the first publicly available data release from SMGPS which comprises data cubes of frequency-resolved images over 908--1656 MHz, power law fits to the images, and broadband zeroth moment integrated intensity images. A thorough assessment of the data quality and guidance for future usage of the data products are given. Finally, we discuss the tremendous potential of SMGPS by showcasing highlights of the Galactic and extragalactic science that it permits. These highlights include the discovery of a new population of non-thermal radio filaments; identification of new candidate supernova remnants, pulsar wind nebulae and planetary nebulae; improved radio/mid-IR classification of rare Luminous Blue Variables and discovery of associated extended radio nebulae; new radio stars identified by Bayesian cross-matching techniques; the realisation that many of the largest radio-quiet WISE HII region candidates are not true HII regions; and a large sample of previously undiscovered background HI galaxies in the Zone of Avoidance
The 1.28 GHz MeerKAT DEEP2 Image
We present the confusion-limited 1.28 GHz MeerKAT DEEP2 image covering one qb » ¢ 68 FWHM primarybeam area with θ = 7 6 FWHM resolution and s = m - n 0.55 0.01 Jy beam 1 rms noise. Its J2000 center position
α = 04h 13m 26 4, δ = −80° 00′ 00″ was selected to minimize artifacts caused by bright sources. We introduce
the new 64-element MeerKAT array and describe commissioning observations to measure the primary-beam
attenuation pattern, estimate telescope pointing errors, and pinpoint (u, v) coordinate errors caused by offsets in
frequency or time. We constructed a 1.4 GHz differential source count by combining a power-law count fit to the
DEEP2 confusion P(D) distribution from 0.25 to 10 μJy with counts of individual DEEP2 sources between 10 μJy
and 2.5 mJy. Most sources fainter than S ∼ 100 μJy are distant star-forming galaxies (SFGs) obeying the far-IR/
radio correlation, and sources stronger than 0.25 μJy account for ∼93% of the radio background produced by
SFGs. For the first time, the DEEP2 source count has reached the depth needed to reveal the majority of the star
formation history of the universe. A pure luminosity evolution of the 1.4 GHz local luminosity function consistent
with the Madau & Dickinson model for the evolution of SFGs based on UV and infrared data underpredicts our
1.4 GHz source count in the range -5 log Jy 4 [ ( )] S
The SARAO MeerKAT 1.3 GHz Galactic Plane Survey
We present the SARAO MeerKAT Galactic Plane Survey (SMGPS), a 1.3 GHz continuum survey of almost half of the Galactic Plane (251○ ≤l ≤ 358○ and 2○ ≤l ≤ 61○ at |b| ≤ 1
5). SMGPS is the largest, most sensitive and highest angular resolution 1 GHz survey of the Plane yet carried out, with an angular resolution of 8″ and a broadband RMS sensitivity of ∼10–20 μJy beam−1. Here we describe the first publicly available data release from SMGPS which comprises data cubes of frequency-resolved images over 908–1656 MHz, power law fits to the images, and broadband zeroth moment integrated intensity images. A thorough assessment of the data quality and guidance for future usage of the data products are given. Finally, we discuss the tremendous potential of SMGPS by showcasing highlights of the Galactic and extragalactic science that it permits. These highlights include the discovery of a new population of non-thermal radio filaments; identification of new candidate supernova remnants, pulsar wind nebulae and planetary nebulae; improved radio/mid-IR classification of rare Luminous Blue Variables and discovery of associated extended radio nebulae; new radio stars identified by Bayesian cross-matching techniques; the realisation that many of the largest radio-quiet WISE H II region candidates are not true H II regions; and a large sample of previously undiscovered background H I galaxies in the Zone of Avoidance
The MeerKAT Galaxy Cluster Legacy Survey: I. Survey overview and highlights
Please abstract in the article.The South African Radio Astronomy Observatory (SARAO), the National Research Foundation (NRF), the National Radio Astronomy Observatory, US National Science Foundation, the South African Research Chairs Initiative of the DSI/NRF, the SARAO HCD programme, the South African Research Chairs Initiative of the Department of Science and Innovation.http://www.aanda.orghj2022Physic
The effect of gender and ethnic differences on the success of intervention programmes for the motor proficiency and self-concept of 7-9 year old DCD children
More boys than girls are diagnosed with DCD (Maldonadoo-Duran, 2002), while
boys have a higher global (Davies & Brember, 1999) and physical self-concept
(Crocker et al., 2000) than girls. However, no literature exists with regard to ethical
differences. Teachers identified 201 potential DCD candidates. The Movement
Assessment Battery for Children (Henderson & Sugden, 1992) identified 58 with
DCD (36 boys and 22 girls). The Tennessee Self-Concept Scale (Child Form) (Fitts
& Warren, 1996) and Child Anxiety Scale (Gillis, 1980) were administered to
determine the children's self-concept and anxiety respectively. A four-group pretestposttest,
with two follow-up tests was used. Children were randomly grouped into
experimental groups (motor based intervention, self-concept enhancing intervention,
integrated psycho-motor intervention and control group). A repeated measures
ANOVA was used to determine interactions within the groups, independent t-tests to
determine gender differences and a one-way ANOVA to determine differences
between the ethnic groups. The self-concept of the girls in the psychological group
improved moderately significantly (p=0.09) more than that of the boys, while the
white children's motor proficiency (motor based intervention group) improved
significantly more than the black children's. These differences were, however, not
large enough to justify different intervention programmes for different ethnic groups
and genders. Keywords: Gender; Ethnic; Race; Children; DCD. South African Journal for Research in Sport, Physical Education and Recreation Vol. 29 (1) 2007: pp. 113-12
Ethical considerations in kinderkinetics research
There are certain ethical considerations that should be taken into account when research that involves young children, is planned. The purpose of this study was to determine certain pitfalls that Kinderkineticists experience while doing research involving young children. Out of this study it is clear that there are many guidelines that need to be followed when research involving young children is conducted. The major guideline that is mentioned is the necessity of informed consent. The guidelines found in the medical research council are stipulated in this article. Certain pitfalls that Kinderkineticists then experience in the research process are also mentioned. One of the major problems in South Africa is the multicultural nature of the land with eleven official languages. This leads to a language barrier during the research process. In conclusion it can be said that good planning of the research project, to foresee the pitfalls are very important, in order to have a successful research project. African Journal for Physical, Health Education, Recreation and Dance Vol. 13 (1) 2007: pp. 103-11