372 research outputs found
Comparative performance of rural water supplies during drought
As rural African communities experience more frequent and extreme droughts, it is increasingly important that water supplies are climate resilient. Using a unique temporal dataset we explore rural water supply (nâ=â5196) performance during the 2015â16 drought in Ethiopia. Mean functionality ranged from 60% for motorised boreholes to 75% for hand-pumped boreholes. Real-time monitoring and responsive operation and maintenance led to rapid increases in functionality of hand-pumped and, to a lesser extent, motorised boreholes. Increased demand was placed on motorised boreholes in lowland areas as springs, hand-dug-wells and open sources failed. Most users travelled >1âh to access motorised boreholes but 30âm) groundwater performed best during the drought. Prioritising access to groundwater via multiple improved sources and a portfolio of technologies, such as hand-pumped and motorised boreholes, supported by responsive and proactive operation and maintenance, increases rural water supply resilience
A hidden crisis: strengthening the evidence base on the sustainability of rural groundwater supplies: results from a pilot study in Uganda
Extending and sustaining access to rural water supplies remains central to improving the health and
livelihoods of poor people, particularly women, in Africa, where 400 million rural inhabitants have no
form of utility provided water, and universal access to water hinges on accelerated development of
groundwater (UN 2013). The âfuture proofingâ of groundwater investments is therefore vital,
especially in the context of global and local trends including demographic shifts, environmental
impacts of human activity and climate change (Taylor et al. 2013).
The emphasis, in recent years, on accelerating access to new infrastructure has obscured a hidden
crisis of failure. More than 30% of sources are nonâfunctional within a few years of construction
(Rietveld et al. 2009, RWSN 2009, Lockwood et al. 2011) and a greater number are seasonal (for
example 50% in Sierra Leone) (MoEWR 2012). The accumulated costs to governments, donors, and,
above all, rural people, are enormous. The original benefits generated by the new infrastructure â
improved health, nutrition, time savings, education, particularly for the poorest â are lost if
improved services cannot be sustained. The cumulative effect of rural water supply failure in Africa
over the past 20 years has been estimated by the World Bank to represent a lost investment in
excess of $1.2 billion.
Critically, there is limited data or analysis on why sources are nonâfunctional and therefore little
opportunity to learn from past mistakes.
This report provides a summary of the work undertaken by the UKâfunded UPGro research
programme ('Unlocking the Potential for Groundwater for the Poor') for subâSaharan Africa (SSA)
funded by the Natural Environment Research Council (NERC), the Economic and Social Research
Council (ESRC) and the Department for International Development (DfID). The Catalyst Grant project
âA Hidden Crisisâ was aimed at developing a methodology and toolbox to investigate the causes of
failure in groundwaterâbased water services in SSA, which could form the foundation for more
substantial and largerâscale research in the future to develop a statistically significant evidence base
to examine water point functionality and the underlying causes of failure across a range of physical,
social, institutional and governance environments in SSA. To test the toolbox and methodology
developed, a pilot study was conducted in northeast Uganda
Overall, the approach and methods developed in the catalyst project have been shown to make a
significant step towards developing a replicable and robust methodology which can be used to
generate a systematic evidence base for supply failure. The work has gone a significant way to
encapsulating the complexity of the interlinked aspects of the problem, balancing the natural science
and engineering (âtechnicalâ) aspects of the research with those concerning the ability of
communities to manage and maintain their water points (the âsocialâ aspects). The multiplicity of
interlinked causes of water point failure was explicitly acknowledged and taken into account through
the use of multiâdisciplinary field and analytical methods within the toolbox and in selection of the
research team. The multiâdisciplinary methods of investigation used were highly practical and
appropriate to the information sought, and based on detailed observational science
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Groundwater and resilience to drought in the Ethiopian Highlands
During drought, groundwater is often relied on to provide secure drinking water, particularly in rural Africa where other options are limited. However, the technology chosen to access groundwater significantly affects local water security. Here we examine the performance of springs, hand-dug- wells and boreholes in northern Ethiopia through direct high frequency monitoring of water-levels (n=19) and water quality (n=48) over an 18-month period and gathering information on community impacts of declining water access during the El Niño 2015/2016 drought. We found that shallow boreholes equipped with handpumps were the most reliable water supply, recovering within hours to daily abstraction throughout all conditions. Recovery and performance of most hand-dug-wells and springs declined significantly throughout the extended dry season, although in specific aquifer conditions they were reliable. All sources types had negligible measured contamination from Thermo-tolerant Coliforms through the extended dry season, but were contaminated during the rains marking drought cessation. Boreholes were least affected, median 10 cfu/100ml, compared to 190 and 59 cfu/100ml for hand-dug-wells and springs respectively. Many communities who relied solely on springs, wells or rivers experienced severe water shortage in the El Niño drought with mean daily collection times up to 12 hours and volumes collected reducing to 3-5 litre- per-capita- per-day. This led to reports of violent conflict, missed meals, reduction in school attendance and farm activity and increased health impacts. From this study there is a clear case for improving resilience to drought by installing boreholes equipped with handpumps where feasible even if collection times are >30 minutes
A hidden crisis: strengthening the evidence base on the current failure of rural groundwater supplies
New ambitious international goals for universal access to safe drinking water depend critically on the ability of development partners to accelerate and sustain access to groundwater. However, available evidence (albeit fragmented and methodologically unclear) indicates >30% of new groundwater-based supplies are non-functional within a few years of construction. Critically, in the absence of a significant systematic evidence base or analysis on supply failures, there is little opportunity to learn from past mistakes, to ensure more sustainable services can be developed in the future. This work presents a new and robust methodology for investigating the causes of non-functionality, developed by an interdisciplinary team as part of a UK-funded development research project. The approach was successfully piloted within a test study in NE Uganda, and forms a basis for future research to develop a statistically significant systematic evidence base to unravel the underlying causes of failur
The scaling of postcranial muscles in cats (Felidae) I: forelimb, cervical, and thoracic muscles
The body masses of cats (Mammalia, Carnivora, Felidae) span a ~300âfold range from the smallest to largest species. Despite this range, felid musculoskeletal anatomy remains remarkably conservative, including the maintenance of a crouched limb posture at unusually large sizes. The forelimbs in felids are important for body support and other aspects of locomotion, as well as climbing and prey capture, with the assistance of the vertebral (and hindlimb) muscles. Here, we examine the scaling of the anterior postcranial musculature across felids to assess scaling patterns between different species spanning the range of felid body sizes. The muscle architecture (lengths and masses of the muscleâtendon unit components) for the forelimb, cervical and thoracic muscles was quantified to analyse how the muscles scale with body mass. Our results demonstrate that physiological crossâsectional areas of the forelimb muscles scale positively with increasing body mass (i.e. becoming relatively larger). Many significantly allometric variables pertain to shoulder support, whereas the rest of the limb muscles become relatively weaker in larger felid species. However, when phylogenetic relationships were corrected for, most of these significant relationships disappeared, leaving no significantly allometric muscle metrics. The majority of cervical and thoracic muscle metrics are not significantly allometric, despite there being many allometric skeletal elements in these regions. When forelimb muscle data were considered in isolation or in combination with those of the vertebral muscles in principal components analyses and MANOVAs, there was no significant discrimination among species by either size or locomotory mode. Our results support the inference that larger felid species have relatively weaker anterior postcranial musculature compared with smaller species, due to an absence of significant positive allometry of forelimb or vertebral muscle architecture. This difference in strength is consistent with behavioural changes in larger felids, such as a reduction of maximal speed and other aspects of locomotor abilities
A semi-synthetic oligosaccharide conjugate vaccine candidate confers protection against Streptococcus pneumoniae serotype 3 infection
The identification of immunogenic glycotopes that render glycoconjugate vaccines protective is key to improving vaccine efficacy. Synthetic oligosaccharides are an attractive alternative to the heterogeneous preparations of purified polysaccharides that most marketed glycoconjugate vaccines are based on. To investigate the potency of semi-synthetic glycoconjugates, we chose the least-efficient serotype in the current pneumococcal conjugate vaccine Prevnar 13, Streptococcus pneumoniae serotype 3 (ST3). Glycan arrays containing synthetic ST3 repeating unit oligosaccharides were used to screen a human reference serum for antibodies and to define the recognition site of two ST3-specific protective monoclonal antibodies. The glycan array screens identified a tetrasaccharide that was selected for in-depth immunological evaluation. The tetrasaccharide-CRM197 carrier protein conjugate elicited protective immunity as evidenced by opsonophagocytosis assays and protection against pneumonia caused by ST3 in mice. Formulation of the defined protective lead candidate glycotope has to be further evaluated to elicit optimal long-term immunity
Cytogerontology since 1881: A reappraisal of August Weismann and a review of modern progress
Cytogerontology, the science of cellular ageing, originated in 1881 with the prediction by August Weismann that the somatic cells of higher animals have limited division potential. Weismann's prediction was derived by considering the role of natural selection in regulating the duration of an organism's life. For various reasons, Weismann's ideas on ageing fell into neglect following his death in 1914, and cytogerontology has only reappeared as a major research area following the demonstration by Hayflick and Moorhead in the early 1960s that diploid human fibroblasts are restricted to a finite number of divisions in vitro.
In this review we give a detailed account of Weismann's theory, and we reveal that his ideas were both more extensive in their scope and more pertinent to current research than is generally recognised. We also appraise the progress which has been made over the past hundred years in investigating the causes of ageing, with particular emphasis being given to (i) the evolution of ageing, and (ii) ageing at the cellular level. We critically assess the current state of knowledge in these areas and recommend a series of points as primary targets for future research
Groundwater resources in the Indo-Gangetic Basin : resilience to climate change and abstraction
Groundwater within the IndoâGangetic Basin (IGB) alluvial aquifer system forms one of the
worldâs most important and heavily exploited reservoirs of freshwater. In this study we
have examined the groundwater system through the lens of its resilience to change â both
from the impact of climate change and increases in abstraction. This has led to the
development of a series of new maps for the IGB aquifer, building on existing datasets held
in Pakistan, India, Nepal and Bangladesh, a review of approximately 500 reports and papers,
and three targeted field studies on underâresearched topics within the region. The major
findings of the study are described below.
The IGB groundwater system
1. The IGB alluvial aquifer system comprises a large volume of heterogeneous
unconsolidated sediment in a complex environmental setting. Annual rainfall varies
from 2000mm in the Bengal basin, and the
system is dissected by the major river systems of the Indus, Ganges and Brahmaputra.
The groundwater system has been modified by the introduction of large scale canal
irrigation schemes using water from the Indus and Ganges since the 19th and early 20th
centuries.
2. High yielding tubewells can be sustained in most parts of the alluvial aquifer system;
permeability is often in the range of 10 â 60 m/d and specific yield (the drainable
porosity) varies from 5 â 20%, making it highly productive.
3. High salinity and elevated arsenic concentrations exist in parts of the basin limiting the
usefulness of the groundwater resource. Saline water predominates in the Lower Indus,
and near to the coast in the Bengal Delta, and is also a major concern in the Middle
Ganges and Upper Ganges (covering much of the Punjab Region in Pakistan, southern
Punjab, Haryana and parts of Uttar Pradesh in India). Arsenic severely impacts the
development of shallow groundwater in the fluvial influenced deltaic area of the Bengal
Basin.
4. Recharge to the IGB aquifer system is substantial and dynamic, controlled by monsoonal
rainfall, leakage from canals, river infiltration and irrigation returns. Recharge from
rainfall can occur even with low annual rainfall (350 mm) and appears to dominate
where rainfall is higher (> 750 mm). Canal leakage is also highly significant and
constitutes the largest proportion of groundwater recharge in the drier parts of the
aquifer, partially mitigating the effects of abstraction on groundwater storage.
5. Deep groundwater (>150 m) in the Bengal basin has strategic value for water supply,
health and economic development. Excessive abstraction poses a greater threat to the
quality of this deep groundwater than climate change. Heavy pumping may induce the
downward migration of arsenic in parts of Bangladesh, and of saline water in coastal
regions, but field evidence and modelling both suggest that deep groundwater
abstraction for public water supply in southern Bangladesh is in general secure against
widespread ingress of arsenic and saline water for at least 100 years
A hidden crisis: strengthening the evidence base on the current failures of rural groundwater supplies
New ambitious international goals for universal access to safe drinking water depend critically on the ability of development partners to accelerate and sustain access to groundwater. However, available evidence (albeit fragmented and methodologically unclear) indicates >30% of new groundwater-based supplies are non-functional within a few years of construction. Critically, in the absence of a significant systematic evidence base or analysis on supply failures, there is little opportunity to learn from past mistakes, to ensure more sustainable services can be developed in the future. This work presents a new and robust methodology for investigating the causes of non-functionality, developed by an interdisciplinary team as part of an UPGro catalyst grant. The approach was successfully piloted within a test study in NE Uganda, and forms a basis for future research to develop a statistically significant systematic evidence base to unravel the underlying causes of failure
Sex-specific local life-history adaptation in surface- and cave-dwelling Atlantic mollies (Poecilia mexicana)
Cavefishes have long been used as model organisms showcasing adaptive diversification, but does adaptation to caves also facilitate the evolution of reproductive isolation from surface ancestors? We raised offspring of wild-caught surface- and cave-dwelling ecotypes of the neotropical fish Poecilia mexicana to sexual maturity in a 12-month common garden experiment. Fish were raised under one of two food regimes (high vs. low), and this was crossed with differences in lighting conditions (permanent darkness vs. 12:12âh light:dark cycle) in a 2âĂâ2 factorial design, allowing us to elucidate potential patterns of local adaptation in life histories. Our results reveal a pattern of sex-specific local life-history adaptation: Surface molly females had the highest fitness in the treatment best resembling their habitat of origin (high food and a light:dark cycle), and suffered from almost complete reproductive failure in darkness, while cave molly females were not similarly affected in any treatment. Males of both ecotypes, on the other hand, showed only weak evidence for local adaptation. Nonetheless, local life-history adaptation in females likely contributes to ecological diversification in this system and other cave animals, further supporting the role of local adaptation due to strong divergent selection as a major force in ecological speciation
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