29,442 research outputs found

    Homo Datumicus : correcting the market for identity data

    Get PDF
    Effective digital identity systems offer great economic and civic potential. However, unlocking this potential requires dealing with social, behavioural, and structural challenges to efficient market formation. We propose that a marketplace for identity data can be more efficiently formed with an infrastructure that provides a more adequate representation of individuals online. This paper therefore introduces the ontological concept of Homo Datumicus: individuals as data subjects transformed by HAT Microservers, with the axiomatic computational capabilities to transact with their own data at scale. Adoption of this paradigm would lower the social risks of identity orientation, enable privacy preserving transactions by default and mitigate the risks of power imbalances in digital identity systems and markets

    Comparisons of soil suction induced by evapotranspiration and transpiration of S. <i>heptaphylla</i>

    Get PDF
    For a given evapotranspiration (ETr), both soil evaporation and plant transpiration (Tr) would induce soil suction. However, the relative contribution of these two processes to the amount of suction induced is not clear. The objective of this study is to quantify ETr- and Tr-induced suction by a selected tree species, Scheffllera heptaphylla, in silty sand. The relative contribution of transpiration and evaporation to the responses of suction is then explored based on observed differences in Tr- and ETr-induced suction. In total, 12 test boxes were used for testing: 10 for vegetated soil with different values of leaf area index (LAI) and root area index (RAI), while two were for bare soil as references. Each box was exposed to identical atmospheric conditions controlled in a plant room for monitoring suction responses over a week. Due to the additional effects of soil evaporation, ETr-induced suction could be 3%–47% higher than Tr-induced suction, depending on LAI. The significance of evaporation reduced substantially when LAI was higher, as relatively less radiant energy fell on the soil surface for evaporation. For a given LAI, the effects of evaporation were less significant at deeper depths within the root zone. The effects of RAI associated with root-water uptake upon transpiration were the dominant process of ETr affecting the suction responses.</jats:p

    Steady state and dynamic properties of journal bearings in laminar and superlaminar flow regimes. II - Full floating ring bearings

    Get PDF
    Steady state and dynamic properties of journal bearings in laminar and superlaminar flow regime

    Fitting Pulsar Wind Tori. II. Error Analysis and Applications

    Full text link
    We have applied the torus fitting procedure described in Ng & Romani (2004) to PWNe observations in the Chandra data archive. This study provides quantitative measurement of the PWN geometry and we characterize the uncertainties in the fits, with statistical errors coming from the fit uncertainties and systematic errors estimated by varying the assumed fitting model. The symmetry axis Ψ\Psi of the PWN are generally well determined, and highly model-independent. We often derive a robust value for the spin inclination ζ\zeta. We briefly discuss the utility of these results in comparison with new radio and high energy pulse measurementsComment: 15 pages, 3 figures, ApJ in pres

    Optical surface waves in periodic layered medium grown by liquid phase epitaxy

    Get PDF
    Optical surface waves propagating along the surface of a multilayer stack have been observed. The multilayer stack is grown by liquid phase epitaxy. The transverse intensity distribution measured is found to agree with our theoretical calculation

    [CI], [CII] and CO emission lines as a probe for alpha variations at low and high redshifts

    Full text link
    The offsets between the radial velocities of the rotational transitions of carbon monoxide and the fine structure transitions of neutral and singly ionized carbon are used to test the hypothetical variation of the fine structure constant, alpha. From the analysis of the [CI] and [CII] fine structure lines and low J rotational lines of 12CO and 13CO, emitted by the dark cloud L1599B in the Milky Way disk, we find no evidence for fractional changes in alpha at the level of |Δα/α\Delta \alpha/\alpha| < 3*10^-7. For the neighbour galaxy M33 a stringent limit on Delta alpha/alpha is set from observations of three HII zones in [CII] and CO emission lines: |Δα/α\Delta \alpha/\alpha| < 4*10^-7. Five systems over the redshift interval z = 5.7-6.4, showing CO J=6-5, J=7-6 and [CII] emission, yield a limit on |Δα/α\Delta \alpha/\alpha| < 1.3*10^-5. Thus, a combination of the [CI], [CII], and CO emission lines turns out to be a powerful tool for probing the stability of the fundamental physical constants over a wide range of redshifts not accessible to optical spectral measurements.Comment: 10 pages, 3 figures, 5 tables. Accepted for publication in MNRA
    corecore