The Evolution of Cas A at Low Radio Frequencies

We have used archival 74 MHz VLA data spanning the last 15 years in combination with new data from the Long Wavelength Demonstrator Array (LWDA) and data from the literature covering the last 50 years to explore the evolution of Cas A at low radio frequencies. We find that the secular decrease of the flux density of Cas A at ~80 MHz is rather stable over five decades of time, decreasing at a rate of 0.7-0.8% yr^-1. This is entirely consistent with previous estimates at frequencies as low as 38 MHz, indicating that the secular decrease is roughly the same at low frequencies, at least between 38 and 80 MHz. We also find strong evidence for as many as four modes of flux density oscillation about the slower secular decrease with periods of 3.10+/-0.02$ yr, 5.1+/-0.3 yr, 9.0+/-0.2 yr, and 24+/-2 yr. These are also consistent with fluctuations seen previously to occur on scales of a few years. These results provide compelling motivation for a thorough low frequency monitoring campaign of Cas A to constrain the nature and physical origins of these fluctuations, and to be able to better predict the flux density of Cas A at any given epoch so that it may be used as a reliable low frequency calibrator.Comment: accepted for publication in A

Parametric modelling of Malaysian teeth template using computer aided design

This study explored a new method and process of design denture using CAD technology to develop a template of a complete denture. Computer aided design were used as a tool of the design process. Occlusion curve was set up as variable as to follow patient size. The maxilla and mandible teeth arrangement were treated as a template of Malaysian user. The accuracy of design is the main aspect of concern that match the patients' data so that the outcome product would be suitable with maximum comfort for the patient. The product of design template will be matched with the conventional method to compare the tolerance between both. The new design template helps to reduce the time consumption of conventional carving method. The final output of 3D geometry teeth templates design will represent the patient details

First Results of the 74 MHz VLA-Pie Town Link. Hercules A at Low Frequencies

We present the results of the first successful observations of the Pie Town link with the Very Large Array (VLA) at 74 MHz on Hercules A. The improvement in resolution from 25 arcsec to 10 arcsec resolves the helical- and ring-like features seen at higher frequencies. We also present new high dynamic range images of this powerful radio galaxy at 325 MHz. Our low frequency observations confirm the multiple outburst interpretation of the spectral index differences at high frequencies. Comparison between our radio and ROSAT X-ray data does not reveal any association between the X-ray emission from the cluster and the radio lobes. There are no extra regions of radio emission at 74 MHz.Comment: 9 pages, 7 figures, accepted for publication in MNRA

G51.04+0.07 and its environment: Identification of a new Galactic supernova remnant at low radio frequencies

We have identified a new supernova remnant (SNR), G51.04+0.07, using observations at 74 MHz from the Very Large Array Low-Frequency Sky Survey Redux (VLSSr). Earlier, higher frequency radio continuum, recombination line, and infrared data had correctly inferred the presence of nonthermal radio emission within a larger, complex environment including ionised nebulae and active star formation. However, our observations have allowed us to redefine at least one SNR as a relatively small source (7.05 × 30in size) located at the southern periphery of the originally defined SNR candidate G51.21+0.11. The integrated flux density of G51.04+0.07 at 74 MHz is 6.1 ± 0.8 Jy, while its radio continuum spectrum has a slope α = −0.52 ± 0.05 (Sν ∝ να), typical of a shell-type remnant. We also measured spatial variations in the spectral index between 74 and 1400 MHz across the source, ranging from a steeper spectrum (α = −0.50 ± 0.04) coincident with the brightest emission to a flatter component (α = −0.30 ± 0.07) in the surrounding fainter region. To probe the interstellar medium into which the redefined SNR is likely evolving, we have analysed the surrounding atomic and molecular gas using the 21 cm neutral hydrogen (HI) and 13CO(J = 1 − 0) emissions. We found that G51.04+0.07 is confined within an elongated HI cavity and that its radio emission is consistent with the remains of a stellar explosion that occurred ∼6300 yr ago at a distance of 7.7 ± 2.3 kpc. Kinematic data suggest that the newly discovered SNR lies in front of HII regions in the complex, consistent with the lack of a turnover in the low frequency continuum spectrum. The CO observations revealed molecular material that traces the central and northern parts of G51.04+0.07. The interaction between the cloud and the radio source is not conclusive and motivates further study. The relatively low flux density (∼1.5 Jy at 1400 MHz) of G51.04+0.07 is consistent with this and many similar SNRs lying hidden along complex lines of sight towards inner Galactic emission complexes. It would also not be surprising if the larger complex studied here hosted additional SNRs.Fil: Supán, Jorge Leonardo. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Castelletti, Gabriela Marta. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Peters, W. M.. Spece Sciences División. Naval Research Laboratory; Estados UnidosFil: Kassim, N. E.. Spece Sciences División. Naval Research Laboratory; Estados Unido

Thermal and Non-thermal Plasmas in the Galaxy Cluster 3C 129

We describe new Chandra spectroscopy data of the cluster which harbors the prototypical "head tail" radio galaxy 3C 129 and the weaker radio galaxy 3C 129.1. We combined the Chandra data with Very Large Array (VLA) radio data taken at 0.33, 5, and 8 GHz (archival data) and 1.4 GHz (new data). We also obtained new HI observations at the Dominion Radio Astrophysical Observatory (DRAO) to measure the neutral Hydrogen column density in the direction of the cluster with arcminute angular resolution. The Chandra observation reveals extended X-ray emission from the radio galaxy 3C 129.1 with a total luminosity of 1.5E+41 erg/s. The X-ray excess is resolved into an extended central source of ~2 arcsec (1 kpc) diameter and several point sources with an individual luminosity up to 2.1E+40 erg/s. In the case of the radio galaxy 3C 129, the Chandra observation shows, in addition to core and jet X-ray emission reported in an earlier paper, some evidence for extended, diffuse X-ray emission from a region east of the radio core. The 12 arcsec x 36 arcsec (6 kpc x 17 kpc) region lies "in front" of the radio core, in the same direction into which the radio galaxy is moving. We use the radio and X-ray data to study in detail the pressure balance between the non-thermal radio plasma and the thermal Intra Cluster Medium (ICM) along the tail of 3C 129 which extends over 15 arcmin (427 kpc). Depending on the assumed lower energy cutoff of the electron energy spectrum, the minimum pressure of the radio plasma lies a factor of between 10 and 40 below the ICM pressure for a large part of the tail. We discuss several possibilities to explain the apparent pressure mismatch.Comment: Accepted for publication in MNRAS. Refereed manuscript. 14 pages, 8 figures, additional panel of Fig. 3 shows asymmetric ICM distributio

Low Frequency VLA Observations of Abell 754: Evidence for a Cluster Radio Halo and Possible Radio Relics

We present 74 MHz and 330 MHz VLA observations of Abell 754. Diffuse, halo-like emission is detected from the center of the cluster at both frequencies. At 330 MHz the resolution of 90'' distinguishes this extended emission from previously known point sources. In addition to the halo and at a much lower level, outlying steep-spectrum emission regions straddle the cluster center and are seen only at 74 MHz. The location, morphology and spectrum of this emission are all highly suggestive of at least one, and possibly two cluster radio relics. Easily obtained higher resolution, higher sensitivity VLA observations at both frequencies are required to confirm the extended nature of the halo-like emission and the 74 MHz relic detections. However, since there is prior evidence that this cluster is or has recently been in the process of a major merger event, the possible discovery of relics in this system is of great interest in light of recent observational and theoretical evidence in favor of a merger-relic connection. We discuss the possible role the merger shock waves, which are seen in the X-ray emission, may have played in the formation of the halo and radio relics in A754.Comment: 15 pages including 4 figures. Accepted for publication by Ap

Factors associated with stunting in Dodoma region, Tanzania

Child undernutrition is a major public health concern, claiming the lives of numerous children below five years of age in the developing world. The objective of this study was to assess the factors associated with stunting of children of age 6 – 23 months in Dodoma Municipality and Chamwino District in Dodoma region. Dodoma region located in the central zone of Tanzania was chosen for this study because of its high prevalence (56%) of stunting among children under five years of age. A systematic random sampling technique was used to choose wards, villages, and households that had children aged 6 - 23 months, resulting in 394 households participating in this cross-sectional study. A standardized questionnaire was used to collect socio-demographic information and infant feeding practices. Anthropometric measurements were taken as per WHO standard procedures. A repeated 24-hour dietary recall was used to assess food intake among the study population. Multivariate logistic regression using backward stepwise selection method was used to obtain independent factors of stunting. The overall prevalence of stunting was 40.4% (95% CI; 29.8; 50.9), Chamwino District had a higher prevalence of stunting (44.3%) compared to Dodoma municipality (26.3%). Multivariate logistic regression analysis showed that, age of introduction of complementary food [AOR = 13.3; (95% CI: 2.6 – 67.6)], maternal education [AOR = 5.5; (95% CI: 1.0 – 9.8)], residence in Chamwino District [AOR = 3.2; (95% CI: 1.3 – 5.9)] were factors associated with stunting. About half of the study population (49%) was introduced to complementary foods early, the median age was four months instead of 6 months as recommended by WHO. Infant’s diet was mainly cereal-based, other foods such as animal food source, fruits, and dairy products were consumed by 18%, 11% and 7.1% of children respectively. The dietary pattern of infants was not diversified as 47.7% of infants scored 1 to 3 points out of 12 points categorized as low dietary diversity. Failure to attain normal growth pattern is the most prevalent form of undernutrition in childhood. Associated factors are many, diverse and interrelated. The present study identified maternal education, early introduction of complementary foods and being a resident of Chamwino District as factors to be associated with stunting. Prioritization of identified factors serves as a highlight for better planning of nutrition intervention programs that intend to promote child growth.Key words: Stunting, nutrition status, 6 – 23 months, dietary diversity and complementary foo

Using Semantic Web, Ontologies and Blogs for Knowledge Identification, Organisation and Reuse.

In this paper, we propose an approach to make knowledge-based blogging more interesting, reliable and sophisticated by using semantic web with ontology in the blogging environment. The aim of our research is to realise the knowledge management processes of identification, organisation and reuse (adaptation and application) via the blogging environment for them to be available to users in a seamless application. To achieve knowledge identification, we employ natural language processing techniques coupled with ontologies to identify possible categories of new blog posts. For knowledge organisation, we finalise the categorisation of blog posts and store them into a repository. Finally, in knowledge reuse, we create semantic links between blog posts and other related documents. These processes are integrated in a blogging framework which we call SEMblog

Animal health management practices in zero grazing dairy units in Arusha City, Tanzania

This study aimed at investigating the animal health management practices in zero grazing dairy units. A questionnaire was used to assess the veterinary practices including the administration of antibiotics and other veterinary inputs to promote growth, prevent and treat diseases. Sixty-five (65) respondents were involved in the study. All the respondents (100%) reported that they did not use growth promoters while 98.5% reported the use of prophylactic vaccines. No withdrawal periods were observed for all the prophylactic vaccines given to animals as instructed by Ward Livestock Officers that the vaccines were not harmful to the health of consumers. Of the 65 respondents, 95.4% (62) reported the use of therapeutic antibiotics. The withdrawal period for therapeutic antibiotics ranged from 1 to 3 days as reported by 60% of the respondents while 24.6% (16) reported the withdrawal period of between 4 to 7 days, 4.6% did not observe withdrawal periods and 6.2% depended on the instructions from the veterinarians. Of the respondents, 53.8% attended animal health management training and 59.6% kept no records for any health interventions made to their animals. Based on the observational findings, majority (84.6%) of the cow’s enclosures were of poor hygiene. Warm water was used by 87.7% of the respondents to wash the udders prior to milking, 93.8% used towels to drain water from the udder(s) and100% of farmers lubricated the teats with udder salve prior to milking. Poor hygiene of the enclosures and washing the udders instead of teats only may predispose animals to infectious disease and this may lead to increased use of antibiotics, which may result into emergence of antibiotic resistance. It is, therefore, recommended that farmers should be trained on best animal health management practices such as teat washing, removal of manure from the animal pens as preventive measures for infectious diseases as well as improving the health and productivity of their animals.Keywords: Animal health, management practices, zero grazing, zoonotic infections, antibiotic resistanc