Ghana is the focus of extensive economic development interest, and is undergoing a substantial increase in population from 5 million in 1950 to an estimated 50 million in 2050. Population growth is ...impacting the natural environment, mostly through land cover and land use change (LCLUC), and particularly associated with agriculture expansion and urbanization. Monitoring LCLUC is necessary in order to understand the overall dynamics of population, LCLU and quality of life. However, extensive cloud cover in the region complicates satellite-based monitoring of LCLUC. Our objectives are to evaluate an innovative “dense stack” approach to image classification with extremely cloudy, multi-temporal Landsat 7 ETM+ imagery, map and quantify LCLU within southern Ghana for circa 2000 and circa 2010, examine LCLU changes, and assess the utility of the approach for monitoring human-induced change. Maximum value composite images (derived from the dense stacks) provide unique information for classifying the LCLU classes of interest, and accuracy assessment results indicate effective overall classification of the six LCLU classes mapped using semi-automated methods. A product we developed and refer to as the spectral variability vegetation index (SVVI) plays a major role in discriminating three natural vegetation classes and agriculture. Derived circa 2000 and circa 2010 LCLU maps indicate that approximately 26% of the study area exhibited LCLU change during the study period. Sixty-two percent (62%) of the changes are associated with conversion to Agriculture, with 33% from Secondary Forest, 26% from Savanna, and 3% from Forest. During the same period, 18% of circa 2000 land classified as Agriculture was fallow or abandoned by circa 2010. Change to Built represented 6% of the LCLU change, which includes 5% from Agriculture and 1% from Secondary Forest circa 2000. Freely available Landsat 7 ETM+ imagery and the time-series classification methods developed here may be used to further monitor LCLU change in the region and throughout the world, particularly in cloud-prone equatorial areas.
•Southern Ghana, equatorial study area with extensive cloud cover year round•Dense stack classification approach with Landsat 7 ETM+ time-series data•Novel spectral vegetation index for natural vegetation/agriculture classification•Land cover and land use change from c. 2000 to c. 2010 are mapped and quantified.•Predominant changes are natural veg. to ag. (69%) and ag. to built (6%).
Worldwide variation in human stature and limb proportions is widely accepted to reflect thermal adaptation, but the contribution of population history to this variation is unknown. Furthermore, ...stature and relative lower limb length (LLL) show substantial plastic responses to environmental stressors, e.g., nutrition, pathogen load, which covary with climate. Thus ecogeographic patterns may go beyond temperature-based selection. We analysed global variation in stature, sitting height and absolute and relative LLL using large worldwide samples of published anthropometric data from adult male (n = 571) and female (n = 268) populations in relation to temperature, humidity, and net primary productivity (NPP). Population history was modeled using spatial eigenvector mapping based on geographic distances reflecting the hypothesized pattern for the spread of modern humans out of Africa. Regression models account for ~ 50% of variation in most morphological variables. Population history explains slightly more variation in stature, sitting height and LLL than the environmental/climatic variables. After adjusting for population history, associations between (usually maximum) temperature and LLL are consistent with Allen's "rule" and may drive similar relationships with stature. NPP is a consistent negative predictor of anthropometry, which may reflect the growth-limiting effects of lower environmental resource accessibility (inversely related to NPP) and/or pathogen load.
Luffa spp.
is readily available and widely grown in Asia and Africa and is a rich source of natural fibres for composite development. This paper reviews research findings on
Luffa
fibres and their ...composites. The progress of research, novel findings that affect the paradigm of the research area, recent trends, knowledge gaps and future perspectives are evaluated. It was found that the average chemical composition of
Luffa
fibres ranges from 57–74% cellulose, 14–30% of hemicellulose, 1–22% of lignin and 0–12.8% of the other components.
Luffa
fibres were usually extracted by drying. Furthermore, the most common modification technique was found to be by alkali mercerisation. About 53% of the research studies made use of epoxy resins for their base polymer making it the most popular polymer type for
Luffa
fibre reinforced composites. The composites are fabricated usually by manual mixing and hand layup and the most common curing technique was found to be compression moulding (about 63% of the research studies). The mechanical, thermal, crystalline and other properties of the composites are also considered in this review. Further interesting areas suggested for future work include investigation of the effect of drying, more trials with
L. acutangula
and utilisation of multi-resin ternary systems. It is concluded that
Luffa
is a promising material for composite development and based on its favourable properties is likely to continue playing an important role for the years to come.
This article reports on a cross-country city-based investigation that profiles the middle class in Africa and distinguishes discrete segments that demonstrate the importance of heterogeneity when ...studying the middle class. The authors identify three distinct middle-class segments by administering both qualitative and quantitative questionnaires across ten cities. They explore consumer behavior–related factors, such as lifestyle and purchasing, to answer calls to provide more marketing insight into the African middle class. The discussion also outlines theoretical and managerial implications.
PurposeIn this study, we assess how the mobile phone can be leveraged upon to improve the role of governance in environmental sustainability in 44 Sub-Saharan African ...countries.Design/methodology/approachThe Generalised Method of Moments is used to establish policy thresholds. A threshold is a critical mass or level of mobile phone penetration at which the net effect of governance on carbon dioxide (CO2) emissions changes from positive to negative.FindingsMobile phone penetration thresholds associated with negative conditional effects are: 36 (per 100 people) for political stability/no violence; 130 (per 100 people) for regulation quality; 146.66 (per 100 people) for government effectiveness; 65 (per 100 people) for corruption-control and 130 (per 100 people) for the rule of law. Practical and theoretical implications are discussed.Originality/valueThe study provides thresholds of mobile phone penetration that are critical in complementing governance dynamics to reduce CO2 emissions.
The notion that social protection should be a key strategy for reducing poverty in developing countries has now been mainstreamed within international development policy and practice. Promoted as an ...integral dimension of the post-Washington Consensus that emerged around the turn of the new millennium, all major international development agencies and bilateral donors now include a strong focus on social protection in their advocacy and programmatic interventions, and a commitment to providing social protection was recently enshrined within the Sustainable Development Goals. The rhetoric around social protection, particularly when delivered in the form of cash transfers, has sometimes reached hyperbolic proportions, with advocates seeing it as a silver bullet that can tackle multi-dimensional problems of poverty, vulnerability, and inequality and a southern-led success story that challenges the unequal power relations inherent within international aid. This book examines how the operation of power and politics at multiple levels of governance shapes the extent to which political elites are committed to social protection, the form this commitment takes, and the implications this has not only for the future shape of welfare regimes but also for state–citizen relations on the continent. With a particular focus on cash transfers, the chapters set out how the politics of promoting social protection has played out in countries from all regions of sub-Saharan Africa. The power relations we examine include those that operate within and amongst global development agencies, between global actors and political and bureaucratic elites, and between and amongst political and bureaucratic elites within Africa.
Yellow Fever (YF) is a severe disease caused by Yellow Fever Virus (YFV), endemic in some parts of Africa and America. In Brazil, YFV is maintained by a sylvatic transmission cycle involving ...non-human primates (NHP) and forest canopy-dwelling mosquitoes, mainly Haemagogus-spp and Sabethes-spp. Beginning in 2016, Brazil faced one of the largest Yellow Fever (YF) outbreaks in recent decades, mainly in the southeastern region. In São Paulo city, YFV was detected in October 2017 in Aloutta monkeys in an Atlantic Forest area. From 542 NHP, a total of 162 NHP were YFV positive by RT-qPCR and/or immunohistochemistry, being 22 Callithrix-spp. most from urban areas. Entomological collections executed did not detect the presence of strictly sylvatic mosquitoes. Three mosquito pools were positive for YFV, 2 Haemagogus leucocelaenus, and 1 Aedes scapularis. In summary, YFV in the São Paulo urban area was detected mainly in resident marmosets, and synanthropic mosquitoes were likely involved in viral transmission.
The study examined energy crisis and sought solutions for reforms in the largest regions of the world i.e. East Asia & Pacific, Europe and Central Asia, Latin America & the Caribbean, South Asia, and ...Sub Saharan Africa. The study used number of growth related factors over the period of 1975–2012. The results indicate significant relationship between electric power shortage and growth related specific factors; however, the intensity for each factor varies from region to region. The results of Granger causality verify multiple cause-effect channels in the different regions i.e. feedback hypothesis, economic factors driven electric shortage; electric shortage driven economic factors and no causal relationship between the variables. The results of variance decomposition analysis indicate that greenhouse gas emissions exhibit the largest contribution due to shortages in the electric power transmission. The study opens the debate for environmentalists, government and non-government officials to formulate the sustainable policies related to energy reforms.
In Africa, Old World Primates are involved in the maintenance of sylvatic circulation of ZIKV. However, in Brazil, the hosts for the sylvatic cycle remain unknown. We hypothesized that free-living ...NHPs might play a role in urban/periurban ZIKV dynamics, thus we undertook an NHP ZIKV investigation in two cities in Brazil. We identified ZIKV-positive NHPs and sequences obtained were phylogenetically related to the American lineage of ZIKV. Additionally, we inoculated four C. penicillata with ZIKV and our results demonstrated that marmosets had a sustained viremia. The natural and experimental infection of NHPs with ZIKV, support the hypothesis that NHPs may be a vertebrate host in the maintainance of ZIKV transmission/circulation in urban tropical settings. Further studies are needed to understand the role they may play in maintaining the urban cycle of the ZIKV and how they may be a conduit in establishing an enzootic transmission cycle in tropical Latin America.
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