112 research outputs found

    Assessment of the Extent and Causes of Fuelwood Collection in the Surrounding Communities of Kasewe Reserved Forest, Sierra Leone

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    Seven (7) communities living in and around the Kasewe forest reserved were sampled to assess the extent and causes of fuelwood collection from the reserved forest involving 50 individuals in stratified random technique with a view to evaluate the degree and reasons for fuelwood collection from the Kasewe reserved forest. Data obtained indicate a high frequency of fuelwood harvest in the forest throughout the year. The significant factors affecting such decisions were availability and accessibility, ensure fast cooking process, and cost-effective. In addition, fuelwood activities were intensive throughout the year but peaks late dry season. Hence 48 (96%) of respondents stated forest degradation as one of the significant threats posed by fuelwood collectors to the forest. The study indicates that 100% of the collector are unemployed this was mainly the reason why residents of those communities collect fuelwood from the reserved forest. However, this study concluded that fuelwood collectors were selective over the kind of species they harvest, but the preferred species were not replanted. Fuelwood in the study area is not restricted to domestic use as it is also sold to augment local income. The sale of fuelwood is probably the biggest threat to sustainable utilization of fuelwood and the forest. Therefore, this study recommends that alternatives sources of livelihood and energy be created, among other recommendations for resident communities that will reduce the frequency of harvest from the forest

    Publicā€“Private Partnership: countries' attractiveness and the risk of project failure

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    The primary objective of this thesis is to analyse the public private partnership (PPP) framework for infrastructure development in developing countries across the six regions of the world. The thesis utilises the World Bank's private participation in infrastructure (PPI) dataset for the period 1980ā€“2014, and examines three thematic areas. The first comprises of an exploratory analysis of the PPI dataset. The second research area focuses on the relationship between countries' attractiveness for PPPs and the characteristics of the countries, including: macroeconomic and market; fiscal constraints; regulatory and governance; and experience in PPPs, by utilising the Zero-Inflated Negative Binomial and Cragg's Double Hurdle models in an attempt to model private investors' decision to engage in PPPs as separate participation and consumption decisions. The third research area employs the methodology of survival analysis to investigate the risk of failure of PPP projects based on the allocation of residual facility ownership between the partners. The thesis's primary contributions include the utilisation of a wider and more informative range of econometric methodologies which have not been previously applied to the PPI dataset, and for the first time also, provides a framework to select an appropriate structure for PPPs that will enhance project survival. A key finding of the thesis is that private investors prioritise macroeconomic and market variables, such as price stability over regulatory and governance variables, such as corruption, in their determination as to which country to engage in PPPs. Contrary to previous research, corruption was found to be of no consequence to private investors who wish to engage in PPPs even for developing countries. Another key finding is that PPP projects which confer residual ownership on the public sector have lower risk of failure than those for which such ownership is conferred on the private sector. Evidence also suggests that the size of the project and the participation of multilateral institutions in PPPs also affect the risk of project failure

    EXTRAPOLATION DES SPANNUNGSINTENSITƄTSFAKTORS AUF GRUND EXPERIMENTELLER RESULTATE

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    The stress intensity factor (SIF) is defined usually by following formulas for the fracture-modes l and II, respectively, with the full or half crack-Iength, Ī±, the "far-field" stress Ļƒā‚€ or Ļ„ā‚€ and a dimensionsless quantity kā‚ and kā‚ā‚ depending on the boundary conditions. It is shown, that the actual influence of the crack-length upon the SIF is diminishing with its growing value and in many cases the SIF depends practically on the far-field stress only. This makes an extrapolation method possible, which is checked by two photoelastic experiments

    Multiple sulfur isotopes fractionations associated with abiotic sulfur transformations in Yellowstone National Park geothermal springs

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    Background: The paper presents a quantification of main (hydrogen sulfide and sulfate), as well as of intermediate sulfur species (zero-valent sulfur (ZVS), thiosulfate, sulfite, thiocyanate) in the Yellowstone National Park (YNP) hydrothermal springs and pools. We combined these measurements with the measurements of quadruple sulfur isotope composition of sulfate, hydrogen sulfide and zero-valent sulfur. The main goal of this research is to understand multiple sulfur isotope fractionation in the system, which is dominated by complex, mostly abiotic, sulfur cycling. Results: Water samples from six springs and pools in the Yellowstone National Park were characterized by pH, chloride to sulfate ratios, sulfide and intermediate sulfur species concentrations. Concentrations of sulfate in pools indicate either oxidation of sulfide by mixing of deep parent water with shallow oxic water, or surface oxidation of sulfide with atmospheric oxygen. Thiosulfate concentrations are low (<6 mu mol L-1) in the pools with low pH due to fast disproportionation of thiosulfate. In the pools with higher pH, the concentration of thiosulfate varies, depending on different geochemical pathways of thiosulfate formation. The delta S-34 values of sulfate in four systems were close to those calculated using a mixing line of the model based on dilution and boiling of a deep hot parent water body. In two pools delta S-34 values of sulfate varied significantly from the values calculated from this model. Sulfur isotope fractionation between ZVS and hydrogen sulfide was close to zero at pH < 4. At higher pH zero-valent sulfur is slightly heavier than hydrogen sulfide due to equilibration in the rhombic sulfur-polysulfide - hydrogen sulfide system. Triple sulfur isotope (S-32, S-33, S-34) fractionation patterns in waters of hydrothermal pools are more consistent with redox processes involving intermediate sulfur species than with bacterial sulfate reduction. Small but resolved differences in Delta S-33 among species and between pools are observed. Conclusions: The variation of sulfate isotopic composition, the origin of differences in isotopic composition of sulfide and zero-valent sulfur, as well as differences in Delta S-33 of sulfide and sulfate are likely due to a complex network of abiotic redox reactions, including disproportionation pathways

    Sex Ratio, Gonad Maturity and Size-Structure of Pagelus bellotti in Sierra Leone

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    A total of 135 specimens of Pagellus bellotti were randomly collected from artisanal boats in August 2018. Study of sex ratio, gonad maturity and size-structure of Pagellus bellottii is meagre in Sierra Leone, and forms the basis of the present study. The study will contribute to current knowledge and promote rational exploitation of the stock. Length and weight were measured using a fish measuring board (cm) and digital weight scale (g) respectively. Sex and gonad maturity were macroscopically assessed. Results showed dominant males (71.9%) and significant difference observed (1:2.6) and expected (1:1) female: male sex ratios (p &lt;0.05). Only 11.9% and 11.1% of male and female gonads transcended to the developed stage (Stage IV). The length-frequency distribution for combined sex was unimodal (modal class, 17cm-20.9cm). Mean length and weight respectively were, 19.04\ub10.32cm and 98.85\ub15.08g for males and 17.43\ub10.54cm and 78.61\ub16.32g for females. Growth exponent (b) for male, female and combined sex was 2.809, 2.928 and 2.850 respectively and the correlation coefficient for all sex categories showed (r &gt; 0.9). Indexes of condition were greater than 1.0 (K &gt; 1) for all sex categories. Results portrayed a heterogeneous gender population of Pagelus bellottii and vast similarity in reproductive strategies by both sexes. The fish comprised of one size group and males may be growing larger than the females. Growth pattern was near-isometric for females and negative allometric for the males, and both sexes were in better condition (K &gt;1.0). An annual study could provide further insight

    Hydrogen Cyanide Accumulation and Transformations in Non-polluted Salt Marsh Sediments

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    While cyanide is known to be produced by many organisms, including plants, bacteria, algae, fungi and some animals, it is generally thought that high levels of cyanide in aquatic systems require anthropogenic sources. Here, we report accumulation of relatively high levels of cyanide in non-polluted salt marsh sediments (up to 230 Ī¼mol kg[superscript āˆ’1]). Concentrations of free cyanide up to 1.92 Ī¼mol L[superscript āˆ’1], which are toxic to aquatic life, were detected in the pore-waters. Concentration of total (free and complexed) cyanide in the pore-waters was up to 6.94 Ī¼mol L[superscript āˆ’1]. Free cyanide, which is released to the marsh sediments, is attributed to processes associated with decomposition of cord grass, Spartina alterniflora, roots and possibly from other sources. This cyanide is rapidly complexed with iron and adsorbed on sedimentary organic matter. The ultimate cyanide sink is, however, associated with formation of thiocyanate by reaction with products of sulfide oxidation by Fe(III) minerals, especially polysulfides. The formation of thiocyanate by this pathway detoxifies two poisonous compounds, polysulfides and hydrogen cyanide, preventing release of free hydrogen cyanide from salt marsh sediments into overlying water or air

    The Recharge Potential of Groundwater in the Mokonde Community in Southern Sierra Leone

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    Abstract Understanding the hydrologic budget is crucial in planning for community based water supply. The water budget includes rainfall intensity, groundwater recharge, interception, evapotranspiration, and surface runoff. The percentage of rain going to recharge groundwater, rivers, and lakes is very important from the standpoint of human water consumption and ecosystems service. The objective of this work is to determine the recharge potential of groundwater in the Mokonde Community, Southern Sierra Leone. The community is dependent on wells as the main source of domestic water supply. This research need was born out of the absence of available data to show the relationship between rainfall amounts and groundwater recharge in the study area. In this study we monitored groundwater in a well at the United Methodist Church (UMC) compound at Ngegba Street. Automatic water logging devices were deployed to take readings in water level fluctuations every 15 minutes. Monitoring continued throughout the hydrological year of Sierra Leone. A rain gauge was deployed at neighboring UMC Primary School, and daily rainfall records taken at 9:00 a.m. Our team members also deployed at the well on a daily basis to collect data on abstraction of water. The results revealed, through a 29-year rainfall data and the Specific Yield, that 1170 mm of rainfall (48%) was the maximum potential of rainfall that would make groundwater a convenient source of water supply in the area. This demand was higher with the recent 1-year rainfall data. Increase in settlement had likely led to reduction in pervious area, and hence more and more rainfall needed for recharge. The time it took for maximum recharge (4 weeks) was shorter than that for maximum discharge (28 -30 weeks). Groundwater flowed southwards towards the Gbengitay stream, which drained into the Tia River. These results would inform first step in delineating the water balance in the study area. Future studies could include the quality aspect, stream/river flow, interception and evapotranspiration. These pieces of information are required to help informed decision for water security. A. S. Mansaray et al. 54

    Asymptomatic infection and family contact patterns in households of Ebola Virus Disease survivors, Sierra Leone 2015

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    The data set contains information on 937 people (living and dead) who were resident in the households of people who survived Ebola Virus Disease (EVD) in the Kerry Town Ebola Treatment Centre in Western Area Province, Sierra Leone, during the 2014-2016 epidemic. It includes individual and household characteristics, information on exposure levels, symptoms experienced by individuals during the period when the household was affected by EVD, outcomes, possible routes of transmission, and ELISA results from antibody testing for Ebola IgG in oral fluid. Survivor households were chosen because they were more easily contactable through the Save the Children survivors outreach programme: 123 of 152 survivors and their households were interviewed

    Complicity and contestation in the gentrifying urban primary school.

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    The transformation of primary schools in gentrifying localities has sometimes been referred to as a form of ā€˜class colonisationā€™. This article draws on ethnographic research with teachers, teaching assistants, and parents in two inner-London primary schools to explore the largely unexamined role of school leaders (headteachers) in mediating gentrification processes within urban schools. It argues that institutional history, contexts of headship and leadership style all play an important role in negotiating and recontextualising middle-class mobilisation and power to re-shape primary schools. Headteachersā€™ relationship to gentrification is therefore not simply one of complicity, but often of contestation and conflict. This article therefore challenges understandings of gentrification as a hegemonic process, and contributes to a more nuanced picture of the educational consequences of gentrification, particularly the institutional realities and experiences of urban social change
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