2,649 research outputs found

    A Qualitative Approach to Investigating the Behavioral Definitions of the Four Paradigm Theory of Information Systems Development

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    Hirschheim, Klein and Lyytinen introduced the four-paradigm theory of information systems development (ISD) as a significant attempt to systematise developer assumptions. The theory perspective is that developers hold key assumptions that may be grouped together and classified into paradigms, and that these paradigms influence their ISD behaviour. The aims of the research described here are theory exploration and explanation in case studies concerning the ISD process in three public National Health Service (NHS) institutions in the north of England. We focus on the behavioral rather than the cognitive (assumptions) aspect of the theory. Our conclusions are, firstly, that qualitative theory explanation is desirable because we need to test theory in practice to show its applicability to wider settings. A rigorous qualitative, interpretive method, paying attention to openness and validity, can satisfactorily undertake such theory explanation; such research can help our IS community to gain wider credibility, authority and acceptance. Secondly, with regard to the four-paradigm theory, its predictions were largely met, as the paradigms were capable of classifying developer behaviour and developers had a dominant paradigm, namely functionalism. We found the theory to be very relevant to the investigation of current IS issues, and we introduce the concept of developer paradigmatic inconsistency

    The chemical evolution of local star forming galaxies: Radial profiles of ISM metallicity, gas mass, and stellar mass and constraints on galactic accretion and winds

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    The radially averaged metallicity distribution of the ISM and the young stellar population of a sample of 20 disk galaxies is investigated by means of an analytical chemical evolution model which assumes constant ratios of galactic wind mass loss and accretion mass gain to star formation rate. Based on this model the observed metallicities and their gradients can be described surprisingly well by the radially averaged distribution of the ratio of stellar mass to ISM gas mass. The comparison between observed and model predicted metallicity is used to constrain the rate of mass loss through galactic wind and accretion gain in units of the star formation rate. Three groups of galaxies are found: galaxies with either mostly winds and only weak accretion, or mostly accretion and only weak winds, and galaxies where winds are roughly balanced by accretion. The three groups are distinct in the properties of their gas disks. Galaxies with approximately equal rates of mass-loss and accretion gain have low metallicity, atomic hydrogen dominated gas disks with a flat spatial profile. The other two groups have gas disks dominated by molecular hydrogen out to 0.5 to 0.7 isophotal radii and show a radial exponential decline, which is on average steeper for the galaxies with small accretion rates. The rates of accretion (<1.0 x SFR) and outflow (<2.4 x SFR) are relatively low. The latter depend on the calibration of the zero point of the metallicity determination from the use of HII region strong emission lines.Comment: 19 pages, 17 figure, accepted to MNRA

    Study of Subclinical Mastitis Control on Dry Cow Therapy (DCT) during the Dry Period

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    This aim of study was to indentify the variables supporting the dairy farmers on dry cow therapy (DCT) for contoling subclinical mastitis and impact of the treatment impact on milk production at KPSBU, Lembang, West Java Province. The study was conducted by interviewing the farmers using questionnaires and testing subclinical mastitis using IPB-1 reagen. This study showed that variables supporting the dairy farmers to apply DCT were the attending farmers meeting Odds Ratio (OR) = 4.05; Confidence Interval (CI) = 95% (1.36-12.04) and number of productive dairy OR =5.3; CI 95% (1.43-19.58). The DCT programs were able to improve milk production. The milk production increased 620.5 (76.3-1164.7) litre per cow per year

    Metallicity gradients in local field star-forming galaxies: Insights on inflows, outflows, and the coevolution of gas, stars and metals

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    We present metallicity gradients in 49 local field star-forming galaxies. We derive gas-phase oxygen abundances using two widely adopted metallicity calibrations based on the [OIII]/Hbeta, [NII]/Halpha and [NII]/[OII] line ratios. The two derived metallicity gradients are usually in good agreement within +/-0.14 dex/R25 (R25 is the B-band iso-photoal radius), but the metallicity gradients can differ significantly when the ionisation parameters change systematically with radius. We investigate the metallicity gradients as a function of stellar mass (8<log(M*/Msun)<11) and absolute B-band luminosity (-16 > MB > -22). When the metallicity gradients are expressed in dex/kpc, we show that galaxies with lower mass and luminosity, on average, have steeper metallicity gradients. When the metallicity gradients are expressed in dex/R25, we find no correlation between the metallicity gradients, and stellar mass and luminosity. We provide a local benchmark metallicity gradient of field star-forming galaxies useful for comparison with studies at high redshifts. We investigate the origin of the local benchmark gradient using simple chemical evolution models and observed gas and stellar surface density profiles in nearby field spiral galaxies. Our models suggest that the local benchmark gradient is a direct result of the coevolution of gas and stellar disk under virtually closed-box chemical evolution when the stellar-to-gas mass ratio becomes high (>>0.3). These models imply low current mass accretion rates (<0.3xSFR), and low mass outflow rates (<3xSFR) in local field star-forming galaxies.Comment: 25 pages, 21 figures, accepted to MNRA
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