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91.
Matthew Wilhelm‐Solomon 《Singapore journal of tropical geography》2016,37(3):378-395
In January 2012 the residents of an inner‐city tenement building in Doornfontein, Johannesburg, were evicted on a court order. The building was situated in a post‐industrial neighbourhood in which thousands of South Africans and foreign nationals, many blind or disabled, live in unlawfully occupied buildings without access to water, basic sanitation, electricity and waste management services. Such buildings are known in policy discourse as ‘bad buildings’, and informally as ‘dark buildings’, invoking both a sense of developmental failure and spiritual insecurity. In this paper I analyse how urban renewal policies created social divisions and alliances not only among the residents of Chambers, which were channelled along nationalist lines, but also between the able‐bodied and disabled, and produced new social alliances. In particular, I document how a group of blind Zimbabweans experienced threats of violence and accusations of betrayal, as they were offered alternate accommodation by the evicting company because of their disability. I argue here that the pressures of private‐sector housing developments intersected with the insecurities and divisions of inner‐city social spaces and also fostered new alliances. Following the work of Deleuze and Guattari, I invoke the concept of ‘decoding dispossession’, proposing that ongoing evictions and dispossessions are characterized by simultaneous movements of ‘decoding and deterritorialization’ and ‘overcoding‐reterritorialization’. 相似文献
92.
Kinetics of batch microbial degradation of phenols by indigenous Pseudomonas fluorescence 总被引:1,自引:1,他引:0
S. E. Agarry B. O. Solomon 《International Journal of Environmental Science and Technology》2008,5(2):223-232
The potential of various organisms to metabolize organic compounds has been observed to be a potentially effective means in disposing of hazardous and toxic wastes. Phenols and their compounds have long been recognized as one of the most recalcitrant and persistent organic chemicals in the environment. The bioremediation potential of an indigenous Pseudomonas fluorescence was studied in batch culture using synthetic phenol in water in the concentration range of (100–500) mg/L as a model limiting substrate. The effect of initial phenol concentration on the degradation process was investigated. Phenol was completely degraded at different cultivation times for the different initial phenol concentrations. Increasing the initial phenol concentration from 100 mg/L to 500 mg/L increased the lag phase from 0 to 66 h and correspondingly prolonged the degradation process from 84 h to 354 h. There was decrease in biodegradation rate as initial phenol concentration increased. Fitting data into Monod kinetic model showed the inhibition effect of phenol The kinetic parameters have been estimated up to initial phenol concentration of 500 mg/ L. The rsmax decreased and Ks increased with higher concentration of phenol. The rsmaxhas been found to be a strong function of initial phenol concentration. The culture followed substrate inhibition kinetics and the specific phenol consumption rates were fitted to Haldane, Yano and Koga, Aiba et al., Teissier and Webb models. Between the five inhibition models, the Haldane model was found to give the best fit. Therefore, the biokinetic constants estimated using these models showed good potential of the Pseudomonas fluorescence and the possibility of using it in bioremediation of phenol waste effluents. 相似文献
93.
94.
Hugues Lantuit Pier Paul Overduin Nicole Couture Sebastian Wetterich Felix Aré David Atkinson Jerry Brown Georgy Cherkashov Dmitry Drozdov Donald Lawrence Forbes Allison Graves-Gaylord Mikhail Grigoriev Hans-Wolfgang Hubberten James Jordan Torre Jorgenson Rune Strand ?deg?rd Stanislav Ogorodov Wayne H. Pollard Volker Rachold Sergey Sedenko Steve Solomon Frits Steenhuisen Irina Streletskaya Alexander Vasiliev 《Estuaries and Coasts》2012,35(2):383-400
Arctic permafrost coasts are sensitive to changing climate. The lengthening open water season and the increasing open water area are likely to induce greater erosion and threaten community and industry infrastructure as well as dramatically change nutrient pathways in the near-shore zone. The shallow, mediterranean Arctic Ocean is likely to be strongly affected by changes in currently poorly observed arctic coastal dynamics. We present a geomorphological classification scheme for the arctic coast, with 101,447?km of coastline in 1,315 segments. The average rate of erosion for the arctic coast is 0.5?m? year?1 with high local and regional variability. Highest rates are observed in the Laptev, East Siberian, and Beaufort Seas. Strong spatial variability in associated database bluff height, ground carbon and ice content, and coastline movement highlights the need to estimate the relative importance of shifting coastal fluxes to the Arctic Ocean at multiple spatial scales. 相似文献
95.
Robert G. Strom Maria E. Banks Clark R. Chapman Caleb I. Fassett Jeffrey A. Forde James W. Head III William J. Merline Louise M. Prockter Sean C. Solomon 《Planetary and Space Science》2011,59(15):1960-1967
The primary crater population on Mercury has been modified by volcanism and secondary craters. Two phases of volcanism are recognized. One volcanic episode that produced widespread intercrater plains occurred during the period of the Late Heavy Bombardment and markedly altered the surface in many areas. The second episode is typified by the smooth plains interior and exterior to the Caloris basin, both of which have a different crater size-frequency distribution than the intercrater plains, consistent with a cratering record dominated by a younger population of impactors. These two phases may have overlapped as parts of a continuous period of volcanism during which the volcanic flux tended to decrease with time. The youngest age of smooth plains volcanism cannot yet be determined, but at least small expanses of plains are substantially younger than the plains associated with the Caloris basin. The spatial and temporal variations of volcanic resurfacing events can be used to reconstruct Mercury's geologic history from images and compositional and topographic data to be acquired during the orbital phase of the MESSENGER mission. 相似文献
96.
Jürgen Oberst Stephan Elgner F. Scott Turner Mark E. Perry Robert W. Gaskell Maria T. Zuber Mark S. Robinson Sean C. Solomon 《Planetary and Space Science》2011,59(15):1918-1924
Analysis of images obtained by the MESSENGER spacecraft during its three flybys of Mercury yields a new estimate for the planet's mean radius of 2439.25±0.69 km, in agreement with results from Mariner 10 and Earth-based observations, as well as with MESSENGER altimeter and occultation data. The mean equatorial radius and polar radius are identical to within error, suggesting that rotational oblateness is negligible when compared with other sources of topography. This result is consistent with the small gravitational oblateness of the planet. Minor differences in radius obtained at different locations reflect regional variations in topography. Residual topography along three limb profiles has a dynamic range of 7.4 km and a root-mean-square roughness of 0.8 km over hemispherical scales. Following MESSENGER's entry into orbit about Mercury in March 2011, we expect considerable additional improvements to our knowledge of Mercury's size and shape. 相似文献
97.
Laura Kerber James W. Head David T. Blewett Sean C. Solomon Lionel Wilson Scott L. Murchie Mark S. Robinson Brett W. Denevi Deborah L. Domingue 《Planetary and Space Science》2011,59(15):1895-1909
We present a global survey of candidate pyroclastic deposits on Mercury, derived from images obtained during MESSENGER flybys 1–3 that provided near-global coverage at resolutions between 5 and 0.5 km/pixel. Thirty-five deposits were identified and characterized and are located principally on the floors of craters, along rims of craters, and along the edge of the Caloris basin. Deposits are commonly centered on rimless, often irregularly shaped pits, mostly between 5 and 45 km in diameter. The deposits identified are generally similar in morphology and absolute reflectance to lunar pyroclastic deposits. Spectrally the deposits appear brighter and redder than background Mercury terrain. On the basis of the available coverage, the candidate pyroclastic deposits appear to be essentially globally distributed. The diameters of the deposits, when mapped to lunar gravity conditions, are larger than their lunar counterparts, implying that more abundant volatiles were present during the typical eruptive process than on the Moon. These observations indicate that if these deposits resulted from hawaiian-style eruptions, the volatile contents required would be between ~1600 and 16,000 ppm CO or an equivalent value of H2O, CO2, SO2, or H2S (for a more oxidizing interior), or N2, S2, CS2, S2Cl, Cl, Cl2, or COS (for a more reducing interior). These abundances are much greater than those predicted by existing models for Mercury's formation. An apparent lack of small deposits, compared with the Moon, may be due to resolution effects, a topic that can be further assessed during the orbital phase of the MESSENGER mission. These results provide a framework within which orbital observations by MESSENGER and the future BepiColombo mission can be analyzed. 相似文献
98.
Daniel N. Baker Dusan Odstrcil Brian J. Anderson C. Nick Arge Mehdi Benna George Gloeckler Haje Korth Leslie R. Mayer Jim M. Raines David Schriver James A. Slavin Sean C. Solomon Pavel M. Trávní?ek Thomas H. Zurbuchen 《Planetary and Space Science》2011,59(15):2066-2074
The second and third flybys of Mercury by the MESSENGER spacecraft occurred, respectively, on 6 October 2008 and on 29 September 2009. In order to provide contextual information about the solar wind properties and the interplanetary magnetic field (IMF) near the planet at those times, we have used an empirical modeling technique combined with a numerical physics-based solar wind model. The Wang–Sheeley–Arge (WSA) method uses solar photospheric magnetic field observations (from Earth-based instruments) in order to estimate the inner heliospheric radial flow speed and radial magnetic field out to 21.5 solar radii from the Sun. This information is then used as input to the global numerical magnetohydrodynamic model, ENLIL, which calculates solar wind velocity, density, temperature, and magnetic field strength and polarity throughout the inner heliosphere. WSA-ENLIL calculations are presented for the several-week period encompassing the second and third flybys. This information, in conjunction with available MESSENGER data, aid in understanding the Mercury flyby observations and provide a basis for global magnetospheric modeling. We find that during both flybys, the solar wind conditions were very quiescent and would have provided only modest dynamic driving forces for Mercury's magnetospheric system. 相似文献
99.
Acoustic signals received by platform mounted sonar arrays can be spatially processed to enhance the detection of targets in the presence of both ambient and platform generated (self) noise. Ambient noise in the ocean, such as that due to distant shipping or biological choruses, are known to be spatially correlated. The platform generated noise will be of near-field origin and may not be received by all elements in the array. In this paper we investigate the performance of the minimum variance distortionless response (MVDR) beamformer and the recently introduced Fourier integral method (FIM) and compare their performances with the conventional beamformer. Real passive sonar data, obtained from a platform mounted sparse linear array of hydrophones, is used to study the performance of the beamformers in a typical sonar environment. It is shown that in the absence of self noise, when the array is accurately calibrated the MVDR beamformer will perform very well, but when sensor gain or phase errors are present the performance of the MVDR beamformer is degraded. Further, the MVDR beamformer is unable to reject the self noise which is not "seen" by the entire array. FIM however seems to perform well and a modified version of FIM, which we call weighted FIM (WFIM), is shown to perform better and is at worst comparable to a well calibrated MVDR beamformer 相似文献
100.
Q. Wu D.A. Ortland S.C. Solomon W.R. Skinner R.J. Niciejewski 《Journal of Atmospheric and Solar》2011,73(17-18):2482-2502
Based on TIDI mesospheric wind observations, we analyzed the semidiurnal tide westward zonal wavenumber 1 and 2 (SW1 and SW2) component seasonal, inter-annual variations, and possible sudden stratospheric warming (SSW) related changes. Major findings are as follows: (1) The SW1 has a peak near the South Pole during the December solstice and near the North Pole during the March equinox. (2) The SW2 peaks at 60S and 60N mostly during winter solstices. The SW2 also peaks during late summer and early fall in the northern hemisphere. (3) The QBO effect on the semidiurnal tide is much weaker than that on the diurnal tide. The March equinox northern SW1 zonal amplitude appears to be stronger during the westward phase of the QBO, which is opposite of migrating diurnal tide QBO response. (4) Possible SSW event related changes in the semidiurnal tide are significant but not always consistent. Enhancements in the mid-latitude SW2 component during SSWs are observed, which may be related to the increase of total ozone at mid and high latitudes during SSW events. TIDI observations also show a decrease in the SW2 in the opposite hemisphere during a southern SSW event in 2002. Small increases in the high latitude SW1 in both hemispheres during the 2002 southern SSW event were recorded. 相似文献