A Theory of the Informal Sector

In many countries, especially poor countries, a heavy burden of taxes, bribes, and bureaucratic hassles drives many producers into the informal sector. Is this situation explicable only as a consequence of either the ignorance or the ineptitude of the state authorities? On the contrary this paper shows that we can attribute the existence of a large informal sector to the fact that, because productive endowments contain important unobservable components, the state cannot adjust the amounts that it extracts from producers in the formal sector according to each producer's endowment. Given this fact we find that, if either the distribution of endowments is sufficiently inegalitarian or the production of private substitutes for public services is sufficiently easy, then the state would extract a large enough amount from producers in the formal sector that poorly endowed producers would choose to work in the informal sector. This result obtains both for a proprietary state, which maximizes its own net revenue, and for a hypothetical benevolent state, which would maximize the total net income of producers. But, we also find that a proprietary state would create an informal sector for a larger set of combinations of parameter values than would a hypothetical benevolent state.

Swift Highly Charged Ion Channelling

We review recent experimental and theoretical progress made in the scope of swift highly charged ion channelling in crystals. The usefulness of such studies is their ability to yield impact parameter information on charge transfer processes, and also on some time related problems. We discuss the cooling and heating phenomena at MeV/u energies, results obtained with decelerated H-like ion beams at GSI and with ions having an excess of electrons at GANIL, the superdensity effect along atomic strings and Resonant Coherent Excitation.Comment: to be published in Journal of Physics

An augmented reality interface for visualising and interacting with virtual content

In this paper, a novel AR interface is proposed that provides generic solutions to the tasks involved in augmenting simultaneously different types of virtual information and processing of tracking data for natural interaction. Participants within the system can experience a real-time mixture of 3D objects, static video, images, textual information and 3D sound with the real environment. The userfriendly AR interface can achieve maximum interaction using simple but effective forms of collaboration based on the combinations of humancomputer interaction techniques. To prove the feasibility of the interface, the use of indoor AR techniques are employed to construct innovative applications and demonstrate examples from heritage to learning systems. Finally, an initial evaluation of the AR interface including some initial results is presented

Assessment of environmental impact of solid waste dumpsites using remote sensing

This study presents a remote sensing approach of using freely available Landsat 8 satellite Indicators ( Land Surface Temperature ( LST ), Soil Adjusted Vegetation Index ( SAVI )) and Shuttle Radar Topography Mission (SRTM) Digital Elevation Model (DEM) geospatial data to assess the impact of dumpsites on the environment in Benin City, Nigeria. The fin ding reveals that the average derived LST at the dumpsites were higher than the immediate surrounding, and the average SAVI values were lower than the immediate surrounding. The high values of LST at the dumpsites depict the effect of gases released becaus e of decomposition activities, while low values of SAVI indicate vegetation response to soil and ground water contamination due to leachate infiltration. The average elevation within the dumpsite area derived from SRTM DEM was also applied as a proxy to es timate disposed waste quantity, and related closely with LST that depict biodegradation activities. The result presented here shows that bacterial and fungal counts correlate strongly with the LST and SAVI values at each of the dumpsites R 2 : LST vs Bacteri a Count = 0.982, LST vs Fungi Count = 0.951; SAVI vs Bacteria Count = 0.745, SAVI vs Fungi Count = 0.664, thereby suggesting remote sensing can be applied to aid longterm dumpsite monitoring and management. Keywords: Municipal solid waste, Land Surface Temperature (LST), Soil Adjusted Vegetation Index (SAVI), and Remote sensin

Exact dimer ground state of the two dimensional Heisenberg spin system SrCu_2(BO_3)_2

The two dimensional Heisenberg model for SrCu_2(BO_3)_2 has the exact dimer ground state which was proven by Shastry and Sutherland almost twenty years ago. The critical value of the quantum phase transition from the dimer state to the N\'{e}el ordered state is determined. Analysis of the experimental data shows that SrCu_2(BO_3)_2 has the dimer ground state but is close to the transition point, which leads to the unusual temperature dependence of the susceptibility. Almost localized nature of the triplet excitations explains the plateaus observed in the magnetization curve.Comment: 4 pages, 5 figures, to appear in PR

Micro-deformation of the NEEM ice core: implications for stratigraphic interpretation

第2回極域科学シンポジウム　氷床コアセッション 11月16日（水） 国立極地研究所 2階大会議

Dynamical generation of fuzzy extra dimensions, dimensional reduction and symmetry breaking

We present a renormalizable 4-dimensional SU(N) gauge theory with a suitable multiplet of scalar fields, which dynamically develops extra dimensions in the form of a fuzzy sphere S^2. We explicitly find the tower of massive Kaluza-Klein modes consistent with an interpretation as gauge theory on M^4 x S^2, the scalars being interpreted as gauge fields on S^2. The gauge group is broken dynamically, and the low-energy content of the model is determined. Depending on the parameters of the model the low-energy gauge group can be SU(n), or broken further to SU(n_1) x SU(n_2) x U(1), with mass scale determined by the size of the extra dimension.Comment: 27 pages. V2: discussion and references added, published versio