Use of laser range and height texture cues for building identification

Airborne LiDAR has found application in an increasing number of mapping and Geo-data acquisition tasks. Apart from terrain information generation, applications such as automatic detection and modeling of objects like buildings or vegetation for the generation of 3-D city models have been explored. Besides the height itself, height texture defined by local variations of the height is a significant parameter for object recognition. The paper explores the potential of the analysis of height texture as a cue for the automatic detection of objects in LiDAR datasets. A number of texture measures were computed. Based on their definition and computation these measures were used as bands in a classification algorithm, and objects like buildings, single trees, and roads could be recognized.     

Numerical studies on the structure of the cosmic ray electron halo in starburst galaxies

The structure of the cosmic ray electron halo of a starburst galaxy depends strongly on the nature of galactic wind and the configuration of the magnetic field. We have investigated these dependencies by solving numerically the propagation of electrons originating in starburst galaxies, most likely in supernova remnants. The calculations are made for several models for the galactic winds and for the configuration of the magnetic fields for comparison with observations. Our simulation of a quasi-radio halo reproduces both the extended structure of ∼9 kpc and the subtle hollow structure near the polar region of the radio halo that are observed in the starburst galaxy NGC 253. These findings suggest the existence of strong galactic wind in NGC 253.      

Total evaporation estimation for accurate water accounting purposes: an appraisal of various available estimation methods

The estimation of total evaporation is fundamental for water accounting, considering its influence on water availability. Moreover, the current increase in water consumption (e.g. in sub-Saharan Africa and the world over), land cover/use changes, deteriorating water quality and the climate change projections in most regions of the world underscore the need to understand water loss. So far, different approaches have been developed and implemented in estimating the variations of total evaporation, with varying accuracies. The aim of this work was therefore, to provide a review of these different approaches for estimating total evaporation, as well as a detailed discussion of their strengths and weaknesses. Findings from this review have shown that total evaporation estimates derived, using ground-based meteorological and micro-meteorological methods are inadequate for representing its large-scale spatial variations. On the other hand, remote sensing technology, which acquires data at different resolutions (i.e. radiometric, spectral, spatial and temporal), provides timely, up-to-date and relatively accurate spatial estimates of total evaporation over large geographic coverage, for sustainable and effective water accounting, which is key for well-informed and improved management of water resources at both catchment and regional scales. In this regard, more details on the remote sensing-based methods of estimating total evaporation are provided, especially considering the robust technological advancements and its potential in characterizing earth features over time and space. This work has also managed to identify research gaps and challenges in the accurate estimation of total evaporation, using remote sensing, especially with the emergence of more advanced sensors and the characteristics of the landscape.     

Effect of ocean acidification on coastal phytoplankton composition and accompanying organic nitrogen production

The effect of ocean acidification, caused by the increase in pCO₂ in seawater, on phytoplankton population and on related organic nitrogen production was experimentally examined by use of a natural coastal microbial population. pCO₂ and pH were controlled by aeration with air in which pCO₂ was at the current level (control), for which ambient air was used, and with air in which pCO₂ was ??800?? and ??1200?? ppm, in 500-L culture vessels. The experiment was continued for 15?days after addition of the inorganic nutrients such as nitrate, phosphate, and silicate. During most of the experimental period, a minor increase in phytoplankton biomass was noted, probably because of low irradiance, an increase in phytoplankton biomass was observed at the end of the experiment. Flow cytometric and microscopic observations revealed that this increase was because of Chrysochromulina sp. (Haptophyceae). The growth of Chrysochromulina sp. was most obvious in the control vessel, and tended to be obscured by increasing pCO₂ (decrease in pH), indicating the possibility that ocean acidification inhibits the growth of specific phytoplankton groups, for example Chrysochromulina sp. Production of particulate organic nitrogen (PON), determined by the ¹⁵N tracer method, also diminished under acidified conditions compared with that at the current level.     

Induction of tributyltin-binding protein type 2 in Japanese flounder, Paralichthys olivaceus, by exposure to tributyltin-d27

In this study, individual Japanese flounder were intraperitoneally injected with 2 μg tributyltin-d27 (TBT-d27) fish⁻¹. Blood samples were collected on day 7 after injection. TBT-binding protein types 1 and 2 (TBT-bp1, -bp2) in the blood serum were quantified by western blotting analysis. As a result, the concentration of TBT-bp2 in TBT-d27 treated group increased to 220% of that in the solvent control, whereas the TBT-bp1 concentration decreased to 65% of that in the solvent control. Additionally, a positive relationship between the concentrations of TBT-bp2 and TBT was observed in blood sera of wild and cultured flounder. We suggest that TBT-bp2 is produced in response to TBT exposure and may play an important role in fish physiology.     

Leaching capabilities of iodine monochloride (ICl) and diethylenetriamine pentaacetic acid (DPTA) at different concentrations and pH for some major and trace metals from coal and coal fly ash

In the present study, coal from Chakwal (Pakistan) was leached with an aqueous solutions of iodine monochloride (ICl) and diethylenetriamine pentaacetic acid (DPTA) of different concentrations. The effect of stirring time, concentration and pH was studied on the leaching of different metals from coal. The physicochemical parameters indicated that the coal was of reasonably good quality. The results indicated that with increase in time duration, the extraction of metals increased. In most of the cases, metal concentration increased in the leachate with increasing the concentration of the leaching agents. DPTA was found to be the best leaching agent for most of the metals. Higher extraction of metals from coal fly ash indicated that coal organic matter has a pronounced effect on the leaching. Higher concentration of metals was extracted from virgin coal and coal fly ash at low pH (p?>?0.00) as compared to high pH. DPTA extracted metals in higher concentration from virgin coal and coal fly ash at low pH as compared to ICl. Based on the present study, the most leached metals were Fe, Cu, Mn and the least were Pb, Ni, Cd and Cr.     

Relationships between textural and photoluminescence spectral features of carbonado (natural polycrystalline diamond) and implications for its origin

Field Emission SEM (FESEM) textural observations, crystal size distribution (CSD) analyses, UV-excited luminescence imaging, and photoluminescence (PL) microspectroscopy excited by 488 nm laser were conducted on two texturally contrasting samples of carbonado, a kind of natural polycrystalline diamond from the Central African Republic (CAR). The investigated carbonado samples A and B show extremely different textures: sample A is made up of faceted crystals accompanied by abundant, small rectangular pores, whereas sample B has a granular texture with coarser crystals and scarce, large pores. Diamond crystals smaller than 2–3 µm are enriched in sample A but depleted in sample B. These textural features indicate that sample B diamonds were annealed under thermodynamically stable P–T conditions. The pore characteristics indicate that fluid permeability was higher for sample A than sample B. Photoluminescence (PL) spectra indicate that samples A and B correspond to Group A and B carbonados in the classification of Kagi et al. (1994), respectively, so that sample A reveals emissions from the H3 center without any N–V⁰ derived emission at 575 nm, whereas sample B shows emissions from the 3H center and the N–V⁰ defect. In addition, UV-excited luminescence images and photoluminescence spectra for sample B indicate that the rims of diamond crystals within several microns of a pore show luminescence features similar to those of Group AB carbonados (Kagi et al., 1994), indicating that this Group AB material was formed from Group B by irradiation from pore-filling, radioactive-element-bearing materials at a low temperature. The extent of the low-temperature irradiation is considered to depend on fluid permeability, and the Group A material was strongly irradiated due to its permeable texture whereas the Group B material was not significantly irradiated due to its less permeable granular texture. These results indicate that Group B carbonados have retained their original PL spectral features produced under high pressures and temperatures at mantle depths.     

Estimating spatial variations of total evaporation using multispectral sensors within the uMngeni catchment,South Africa

Total evaporation is of importance in assessing and managing long-term water use, especially in water-limited environments. Therefore, there is need to account for water utilisation by different land uses for well-informed water resources management and future planning. This study investigated the feasibility of using multispectral Landsat 8 and moderate resolution imaging spectroradiometer (MODIS) remote sensing data to estimate total evaporation within the uMngeni catchment in South Africa, using surface energy balance system. The results indicated that Landsat 8 at 30 m resolution has a better spatial representation of total evaporation, when compared to the 1000 m MODIS. Specifically, Landsat 8 yielded significantly different mean total evaporation estimates for all land cover types (one-way ANOVA; F_4.964?=?87.011, p < 0.05), whereas MODIS failed to differentiate (one-way ANOVA; F_2.853?=?0.125, p = 0.998) mean total evaporation estimates for the different land cover types across the catchment. The findings of this study underscore the utility of the Landsat 8 spatial resolution and land cover characteristics in deriving accurate and reliable spatial variations of total evaporation at a catchment scale.     

Study on the geochemical correlation of crude oils of Palaeocene and Jurassic ages from the Potowar Indus Basin in northern Pakistan

This study deals with a detailed geochemical characterization of three crude oils from the Upper Indus Basin, Punjab, Pakistan. The samples were obtained from three productive oil fields of the Datta Formation (Jurassic), Lochhart (Palaeocene) and the Dhak Pass zone (Palaeocene). The GC parameters for and the bulk properties of Datta Formation oils are essentially coincident with those of the oils from the Dhak Pass Formation in the Upper Indus Basin, Pakistan and the oils likely originate from a marine source rock. In contrast, the Lockhart Formation oils show different behaviors and seem to be originated from dirty carbonate rocks although all three crude oils are mature, being of non-biodegraded and somewhat mixed organic matter origin. Low Pr/Ph values and high C₃₅ homohopane index for the Lockhart Formation oils suggest a source of anoxic environment with low Eh while oils from the Datta Formation and Dhak Pass Formation showed different trends, i.e., lower values of C₃₅ homohopane index indicating different depositional environment than oil from the Lockhart Formation. All three crude oils from the Upper Indus Basin are mature for the hopane ratios, i.e., Ts/Ts+Tm, C₃₂22S/(S+R) and C₃₀ αβ/(αβ+βα) and sterane ratios, i.e., C₂₉22S/(S+R) and C₂₉ββ/(ββ+αα) but oils from the Lockhart Formation seem to be less mature than those from the Palaeocene and Datta Formation according to plots like API° vs. homohopane Index, Pr/Ph vs. sterane. The relative composition of 5α(H), 14β(H), 17β(H)-24-ethylecholestanes and the C₂₉20S/20S+20R index, indicate that all three crude oils are equally mature, which makes it unlikely with respect to the above said plots. This difference is may be due to the migratory chromatography which alters the concentrations of sterane and hoapnes and hence gives different results. These oils do not exhibit UCM and have complete n-alkane profiles indicating non-biodegradation.