Thick gas discs in faint dwarf galaxies

We determine the intrinsic axial ratio distribution of the 'gas' disks of extremely faint M_B > -14.5 dwarf irregular galaxies. We start with the measured (beam corrected) distribution of apparent axial ratios in the HI 21cm images of dwarf irregular galaxies observed as part of the Faint Irregular Galaxy GMRT Survey (FIGGS). Assuming that the disks can be approximated as oblate spheroids, the intrinsic axial ratio distribution can be obtained from the observed apparent axial ratio distribution. We use a couple of methods to do this, and our final results are based on using Lucy's deconvolution algorithm. This method is constrained to produce physically plausible distributions, and also has the added advantage of allowing for observational errors to be accounted for. While one might a priori expect that gas disks would be thin (because collisions between gas clouds would cause them to quickly settle down to a thin disk), we find that the HI disks of faint dwarf irregulars are quite thick, with mean axial ratio ~ 0.6. While this is substantially larger than the typical value of ~ 0.2 for the 'stellar' disks of large spiral galaxies, it is consistent with the much larger ratio of velocity dispersion to rotational velocity (sigma/v_c) in dwarf galaxy HI disks as compared to that in spiral galaxies. Our findings have implications for studies of the mass distribution in and the Tully - Fisher relation for faint dwarf irregular galaxies, where it is often assumed that the gas is in a thin disk.Comment: 5 pages, 4 figures. Minor changes in revised version. The definitive version is available at http://www.blackwell-synergy.com

Gas rich galaxies from the FIGGS survey

The FIGGS (Faint Irregular Galaxy GMRT Survey) is aimed at creating a multi-wavelength observational data base for a volume limited sample of the faintest gas rich galaxies. In this paper we discuss two very gas rich galaxies that were observed as part of the FIGGS survey, viz. NGC 3741 and And IV. These galaxies are unusual in that they have extremely extended gas disks and very high ratios of dark to luminous matter. The very extended HI disks provide an unique opportunity to trace the extended distribution of dark matter around faint galaxies. We compare the baryon fraction of these galaxies with a sample of galaxies with well measured rotation curves and discuss whether extremely gas rich dwarf galaxies have abnormally small baryon fractions.Comment: 5 Pages, 4 Figures. To be published in the proceedings of "Galaxies in the Local Volume", ed. B. Koribalski, H. Jerje

Young researchers of the Barents Region

publishedVersio

The Impact of Remittances on Education Attainment: Evidence From Dominican Republic

This paper will examine the relationship between remittances and education attainment focusing on Dominican Republic in 2002. This study will focus on households in Dominican Republic using surveys from IPUMS international and the data is cross-sectional. Sending remittances increases the income for households, which in return, influences the spending on education. The study of remittances is analyzed in a more cultural and social value rather than entirely economic. The dynamic and structure of a family is crucial when studying the effects of remittances in a developing country. Key findings from this analysis is that the relationship between education attainment and remittances are positively related and it is statistically significant according to this model. This study examines the family structure as well as the economic and social structure of Dominican Republic to understand the relationship between remittances and education attainment

Building Information Modeling as Tool for Enhancing Disaster Resilience of the Construction Industry

As frequencies of the disasters are increasing, new technologies can be used to enhance disaster resilience performance of the construction industry. This paper investigates the usage of BIM (Building Information Modeling) in enhancing disaster resilience of the construction industry and in the establishment of the resilient built environment. In-depth literature review findings reveal BIM’s contribution to the disaster resilience in the pre-disaster and post-disaster phases especially through influencing the performance of the supply chain, construction process, and rescue operations. This paper emphasises the need for BIM’s integration to the education and training curriculums of the built environment professionals. Policy makers, construction professionals, professional bodies, academics can benefit from this research

Baryonic Tully-Fisher Relation for Extremely Low Mass Galaxies

We study Tully-Fisher relations for a sample that combines extremely faint (M_B > -14.0) galaxies along with bright (i.e. L_*) galaxies. Accurate (~ 10%) distances, I band photometry, and B-V colors are known for the majority of the galaxies in our sample. The faint galaxies are drawn from the Faint Irregular Galaxy GMRT survey (FIGGS), and we have HI rotation velocities derived from aperture synthesis observations for all of them. For the faint galaxies, we find that even though the median HI and stellar masses are comparable, the HI mass correlates significantly better with the circular velocity indicators than the stellar mass. We also find that W$_{20}$ correlates better with mass than the rotation velocity, although the difference is not statistically significant. The faint galaxies lie systematically below the I band TF relation defined by bright galaxies, and also show significantly more intrinsic scatter. This implies that the integrated star formation in these galaxies has been both less efficient and also less regulated than in large galaxies. We find that while the faint end deviation is greatly reduced in Baryonic Tully-Fisher (BTF) relations, the existence of a break at the faint end of the BTF is subject to systematics such as the assumed stellar mass to light ratio. If we assume that there is an intrinsic BTF and try to determine the baryonic mass by searching for prescriptions that lead to the tightest BTF, we find that scaling the HI mass leads to a much more significant tightening than scaling the stellar mass to light ratio. The most significant tightening that we find however, is if we scale the entire baryonic mass of the faint (but not the bright) galaxies. Such a scenario would be consistent with models where dwarf (but not large) galaxies have a large fraction of dark or ``missing'' baryons (Slightly abridged)Comment: 7 pages, 7 figures. Accepted for publication in MNRA

Reflections on practice-centred curricula in teaching entrepreneurship in Malaysia

This paper discusses the challenges of entrepreneurship education in a regional Malaysian context and provides the design details of entrepreneurship modules providing a practical experience. It is argued that an active, experience-centred module delivery helps to revitalise student curiosity in entrepreneurial activities. The paper utilises the phenomenological approach to explore the contemporary challenges of entrepreneurship education and to gain a deeper insight into its contemporary complexity. The material for the phenomenological analysis is obtained by means of focus groups which are contrasted with the students’ written reflections and staff observations on teaching and learning activities in entrepreneurship modules. The findings indicate that two months timescale for studying entrepreneurship is too short because of competing priorities within the programme of study and an eclectic essence of entrepreneurship. It was also found that students believe that being supported by tutors having practical experience is motivating and reassures them about further learning. The concerns about the applicability of Western concepts of entrepreneurship education to the Malaysian context were not corroborated. It has been argued that practice-centred learning opportunities are often associated with off-campus education and take place in the ‘real world’. The suggested design for standalone entrepreneurship modules evidently ensures a rich experience for students and provides an effective springboard for developing entrepreneurial aspirations

A search for HI in some peculiar faint dwarf galaxies

We present a deep Giant Metrewave Radio Telescope (GMRT) search for HI 21 cm emission from three dwarf galaxies, viz. POX 186, SC 24 and KKR 25. Based, in part, on previous single dish HI observations, these galaxies have been classified as a BCD, a dwarf irregular and a transition galaxy respectively. However, in conflict with previous single dish detections, we do not detect HI in SC 24 or KKR 25. We suggest that the previous single dish measurements were probably confused with the local galactic emission. In the case of POX 186, we confirm the previous non detection of HI but with substantially improved limits on its HI mass. Our derived upper limits on the HI mass of SC 24 and KKR 25 are similar to the typical HI mass limit for dwarf spheroidal galaxies, whereas in the case of POX 186, we find that its gas content is somewhat smaller than is typical of BCD galaxies.Comment: Accepted for publication in MNRA

Reversible Logic Synthesis of Fault Tolerant Carry Skip BCD Adder

Reversible logic is emerging as an important research area having its application in diverse fields such as low power CMOS design, digital signal processing, cryptography, quantum computing and optical information processing. This paper presents a new 4*4 parity preserving reversible logic gate, IG. The proposed parity preserving reversible gate can be used to synthesize any arbitrary Boolean function. It allows any fault that affects no more than a single signal readily detectable at the circuit's primary outputs. It is shown that a fault tolerant reversible full adder circuit can be realized using only two IGs. The proposed fault tolerant full adder (FTFA) is used to design other arithmetic logic circuits for which it is used as the fundamental building block. It has also been demonstrated that the proposed design offers less hardware complexity and is efficient in terms of gate count, garbage outputs and constant inputs than the existing counterparts.Comment: 9 pages, 7 figures, 5 table