Housing strategies in low income urban communities in Accra,Ghana     

Esther Yeboah Danso-Wiredu 《GeoJournal》2018,83(4):663-677

As the rent-free compound housing system in Ghana gradually became unpopular, there was the need for state intervention in housing provision. Housing became an important part of the country’s developmental policies through state interventions prior to the late 1970s. The economic crises in 1979 forced the country to opt for Structural Adjustment Programme, compelling the state to relax on its efforts to provide housing for the public. The paper uses the mode of economic integration framework to discuss the various housing forms in the country. It argues, housing provision led by the private sector creates remarked differences between housing for the higher and lower income groups. The study uses two low income communities in Accra to explain different ways by which the urban poor in Ghana accommodate themselves amidst the country’s housing problems. The study concludes there is an alternative to the housing crises in the country which could be found in the public-private investments in the rental form of the compound housing system.  相似文献   

Late Pleistocene and Holocene Afromontane vegetation and headwater wetland dynamics within the Eastern Mau Forest,Kenya     

Esther N. Githumbi  Colin J. Courtney Mustaphi  Rob Marchant 《第四纪科学杂志》2021,36(2):239-254

The Mau Forest Complex is Kenya's largest fragment of Afromontane forest, providing critical ecosystem services, and has been subject to intense land use changes since colonial times. It forms the upper catchment of rivers that drain into major drainage networks, thus supporting the livelihoods of millions of Kenyans and providing important wildlife areas. We present the results of a sedimentological and palynological analysis of a Late Pleistocene–Holocene sediment record of Afromontane forest change from Nyabuiyabui wetland in the Eastern Mau Forest, a highland region that has received limited geological characterization and palaeoecological study. Sedimentology, pollen, charcoal, X-ray fluorescence and radiocarbon data record environmental and ecosystem change over the last ~16 000 cal a bp. The pollen record suggests Afromontane forests characterized the end of the Late Pleistocene to the Holocene with dominant taxa changing from Apodytes, Celtis, Dracaena, Hagenia and Podocarpus to Cordia, Croton, Ficus, Juniperus and Olea. The Late Holocene is characterized by a more open Afromontane forest with increased grass and herbaceous cover. Continuous Poaceae, Cyperaceae and Juncaceae vegetation currently cover the wetland and the water level has been decreasing over the recent past. Intensive agroforestry since the 1920s has reduced Afromontane forest cover as introduced taxa have increased (Pinus, Cupressus and Eucalyptus).  相似文献   

Transfer of fishing effort between areas and fishery units in Spanish fisheries as side effects of the prestige oil spill management measures     

Esther Abad  Jose M. Bellido  Antonio Punzón 《Ocean & Coastal Management》2010,53(3):107-113

This paper shows how post-oil spill management measures can affect the general pattern of fishing effort exerted on two particular species of great commercial value in northern Spanish fisheries: anglerfish (Lophius piscatorius and Lophius budegassa) and mackerel (Scomber scombrus). Data time series of catches and fishing efforts were analysed corresponding to the area and time period affected by the oil spill fishing restrictions (December 2002–June 2003) and similar previous and post-spill periods. This was done to detect shifts that could be due to either the oil spill per se or the management measures taken to minimise pollution effects. Then, analyses and simulations with Arcview GIS module FAST (Fishing Activity Simulation Tool v. 1.1) were carried out with the aim of studying the fishing effort spatial distribution. Changes were observed in the Catch Per Unit Effort (CPUE) of anglerfish and mackerel by area or fishery unit. Results show a spatial displacement of fishing effort to other fishing areas in the case of anglerfish, and the transfer of fishing effort between different fishery units in the case of mackerel. Although both effects were caused primarily by the management measures in force after the oil spill, they are considered side or collateral effects. The management measures that have to be taken after any disaster should also consider these kinds of ancillary effects as well as evaluating the likely positive or negative impact of these side effects.  相似文献   

A comparison of state space and multiple regression for monthly forecasts: U.S. Fuel consumption     

Kyungcho Bae Recent PhD graduate in Mineral Economics  DeVerle Harris 《Natural Resources Research》1995,4(4):325-339

Monthly consumption forecasts for U.S. oil, natural gas, and coal are made using state space and multiple regression applied to the same data. These forecasts are compared with actual consumption for a test period. The forecasts made using state space are preferred to those made using multiple regression models for both expost and exante cases. The state space forecasts track data cycles better than do the regression forecasts. Average absolute forecast errors are less for the state space models than they are for the multiple regression models.  相似文献   

Volatiles H2O,CO2, and Cl in a subduction related basalt     

David M. Harris  Alfred T. Anderson Jr. 《Contributions to Mineralogy and Petrology》1984,87(2):120-128

The products of the 1974 eruption of Fuego, a subduction zone volcano in Guatemala, have been investigated through study of silicate melt inclusions in olivine. The melt inclusions sampled liquids in regions where olivine, plagioclase, magnetite, and augite were precipitating. Comparisons of the erupted ash, groundmass, and melt inclusion compositions suggest that the inclusions represent samples of liquids present in a thermal boundary layer of the magma body. The concentrations of H₂O and CO₂ in glass inclusions were determined by a vacuum fusion manometric technique using individual olivine crystals (Fo77 to Fo71) with glass inclusion compositions that ranged from high-alumina basalt to basaltic andesite. Water, Cl, and K₂O concentrations increased by a factor of two as the olivine crystals became more iron-rich (Fo77 to Fo71) and as the glass inclusions increased in SiO₂ from 51 to 54 wt.% SiO₂. The concentration of H₂O in the melt increased from 1.6 wt.% in the least differentiated liquid to about 3.5% in a more differentiated liquid. Carbon dioxide is about an order of magnitude less abundant than H₂O in these inclusions. The gas saturation pressures for pure H₂O in equilibrium with the melt inclusions, which were calculated from the glass inclusion compositions using the solubility model of Burnham (1979), are given approximately by P(H₂O)(Pa)=(SiO₂−48.5 wt.%) × 1.45 × 10⁷. The concentrations of water in the melt and the gas saturation pressures increased from about 1.5% to 3.5% and from 300 to 850 bars, respectively, during pre-eruption crystallization.  相似文献   

Initial volatilization temperatures and average volatilization rates of coal — Their relationship to coal rank and other characteristics     

O.C. Kopp  L.A. Harris 《International Journal of Coal Geology》1984,3(4):333-348

Two thermal parameters, initial volatilization temperature (IVT) and average volatilization rate (AVR), have been determined by thermogravimetric analysis in argon for 38 coal samples ranging in rank from lignite to low-volatile bituminous. Both IVT and AVR are correlated with percent volatile matter and vitrinite reflectance.The IVT values increase gradually from about 250 to 445°C with increasing rank; however, a change in slope is observed in the region of high-volatile bituminous coals (from about 340°C to about 380°C) when IVT's are plotted against percent volatile matter or percent fixed carbon. The changes in slope near 340°C and near 380°C occur at “coalification jumps” recognized on the basis of changes in the optical and chemical character of the macerals. In general, AVR values decrease gradually with increasing rank for the lignite and sub-bituminous coals and for the medium- and low-volatile bituminous coals; however, a sharp increase in AVR occurs in high-volatile bituminous coals. The change in slope of the IVT curves and sharp increase in the AVR values for high-volatile bituminous coals reflect the development of new, higher vapor pressure organic compounds produced during this stage of the coalification process.A plot of AVR vs IVT reveals three regions which correspond to: (1) lignite and sub-bituminous coals; (2) high-volatile bituminous coals; and (3) medium- to low-volatile bituminous coals.  相似文献   

Temporal and spatial variations of marine aerosols over the Atlantic Ocean     

F.P. Parungo  C.T. Nagamoto  J.M. Harris 《Atmospheric Research》1986,20(1)

Aerosol samples, collected daily were analyzed with electron microscopy for particle concentration and size distribution. The chemical compositions of individual particles were determined with X-ray energy spectrometry and specific morphological tests. The results demonstrated clear and significant dependencies of aerosol properties on air trajectories computed from a backtrack model. Air parcels, such as American air pollution and Sahara dust, were identified. Their physical mixing and chemical reactions with marine aerosols as well as aerosol wet deposition are discussed.  相似文献   

Earthquake simulator testing of pounding between adjacent buildings     

Manolis Papadrakakis  Harris P. Mouzakis 《地震工程与结构动力学》1995,24(6):811-834

Two-storey-building frames have been designed and built in an effort to investigate the pounding phenomenon of adjacent buildings during earthquakes. Static tests have been first performed to determine the static characteristics and the support conditions of the test structures. Sinusoidal and random acceleration signal tests have been subsequently performed to determine the dynamic characteristics of the test structures. Two series of tests were carried out using the shaking table simulator. In the first case, the dynamic response has been recorded without pounding, while in the second case, the test structures have been placed with zero-gap separation and pounding was induced. Input energy time histories were correlated and compared with and without pounding. The experimental results were compared with analytical ones based on a formulation of the contact impact problem by the Lagrange multiplier method. Good agreement between the experimental and the analytical results was achieved.  相似文献   

Detecting Changes in Ground Water Quality at Regulated Facilities     

Jim C. Loftis  Jane Harris  Robert H. Montgomery 《Ground Water Monitoring & Remediation》1987,7(1):72-76

The Resource Conservation and Recovery Act (PL 94–580) and related federal and state legislation have mandated routine monitoring of ground water quality at regulated facilities. The objective of the required monitoring activities is detection of adverse changes in ground water quality caused by the facilities.
Both failure to detect pollution and an incorrect determination of pollution can be very expensive. It is crucial, therefore, that monitoring programs be designed and operated to provide statistically sound information. It is equally important that users of ground water quality data understand the nature and limitations of information from monitoring.
To address the preceding issues, the authors present a general approach to analyzing ground water quality data in light of the stated monitoring objective. The suggested approach accounts for "natural" variation in background water quality through pairing of observations. The limitations of quarterly sampling for detecting small changes in quality over a short time frame are discussed.  相似文献   

Vertical distribution of plankton in the skagerrak in relation to doming of the seasonal thermocline     

R.D. Pingree  P.M. Holligan  G.T. Mardell  R.P. Harris 《Continental Shelf Research》1982,1(2):209-219

In the central Skagerrak between Norway and Denmark, the seasonal thermocline tends to be relatively shallow (10 to 15 m) probably due to geostrophic effects. An investigation of phytoplankton distribution in this region in late August 1981 showed the presence of an intense subsurface chlorophyll maximum (up to 30 γ 1⁻ Chl a) at a temperature of <6°C, dominated by coccolithophores and the dinoflagellate, Prorocentrum minimum. Data are presented on the vertical distribution of zooplankton in relation to these phytoplankton populations.  相似文献