26 research outputs found

    Managed groundwater development for water-supply security in Sub-Saharan Africa: Investment priorities

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    In numerous countries of Sub-Saharan Africa the strategic agenda of the water-sector is undergoing substantial change because of demographic pressure, climate change and economic transformation. Two new policy questions are arising from the need to make better use of available groundwater storage to improve water-supply security:• What is the scope for promoting much increased groundwater use for irrigated agriculture, and how might the investment risks be reduced and sustainable outcomes ensured?• How can the demand to expand urban groundwater use, for both further supplementing municipal water-supply systems and for direct in situ water supply, be best channelled to maximise the benefits whilst minimising the risks?This ‘new agenda’ poses very different challenges from the long-standing requirement to provide rural water supplies of adequate coverage, reliability and quality (which, while still not yet fully addressed, is outside the scope of this paper). Balanced answers to these new questions are needed to provide a sound basis for appropriate investment policies on managed groundwater development and adequate institutional provisions for their implementation. They are discussed here from the standpoint of the GW-MATE experience in some World Bank-supported projects in eastern Africa during 2001-2010, together with a review of some developments in western Africa and insights from parts of Asia and Latin America

    Low-Cost Aquifer Storage and Recovery: Implications for Improving Drinking Water Access for Rural Communities in Coastal Bangladesh

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    Fresh water resources are scarce in rural communities in the southern deltaic plains of Bangladesh where both shallow and deep groundwater is frequently brackish, and fresh water ponds have been increasingly salinized by inundation during storm surges and brackish-water aquaculture. Low-cost aquifer storage and recovery (ASR) schemes were constructed at 13 villages in three coastal districts by developing storage in shallow confined fine to medium sand aquifers overlain by variable thicknesses of silt and clay. A typical ASR scheme consisted of a double-chambered graded sand filtration tank with a volume of 19.5  m3 that feeds filtered pond water to four to six large diameter (d=30.5 or 56 cm) infiltration wells through PVC pipes fitted with stop valves and flow meters. The infiltration wells were completed at 18–31 m below ground and filled with well-sorted gravel capped with a thin layer of fine sand that acts as a second stage filter. Infiltration rates at 13 sites averaged 3  m3/day (range: 3–6  m3/day) over one year of operation. At 11 sites where water was abstracted, the recovery rate ranged from 5 to 40%. The source pond source water frequently had turbidity values of ≥100  NTU. After sand filtration, the turbidity is typically 5 NTU. Despite this, clogging management involving frequent (monthly to weekly) manual washing to remove fine materials deposited in the sand filtration tank and the infiltration wells is found to be necessary and effective, with post-manual-washing operational infiltration rates restored to annual average values. E. coli counts in recovered water are greatly reduced compared to raw pond water, although E. coli is still detected in about half of the samples. Arsenic in recovered water was detected to be at level of > 100  μg/L repeatedly at three sites, suggesting that As risks must be carefully managed and require further investigation

    The human pathogen Mycobacterium tuberculosis and the fish pathogen Mycobacterium marinum trigger a core set of late innate immune response genes in zebrafish larvae

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    Funding: H.J.J., S.J.R., A.O., M.I.W., C.V.H., P.I.R., N.T.-K. and R.P.D. received funding from the Innovative Medicines Initiative Joint Undertaking under grant agreement n◦ 115337, resources of which are composed of financial contribution from the European Union’s Seventh Framework Program (FP7/2007-2013) and EFPIA companies’ in kind contribution. M.C.H., T.H.M.O. and H.P.S. were supported by a grant from the Innovative Medicines Initiative 2 Joint Undertaking (IMI2 JU) under the RespiriTB project (Grant No. 853903). The authors declare that this study received funding from ZF-Screens B.V., where several authors were employed.Zebrafish is a natural host of various Mycobacterium species and a surrogate model organism for tuberculosis research. Mycobacterium marinum is evolutionarily one of the closest non-tuberculous species related to M. tuberculosis and shares the majority of virulence genes. Although zebrafish is not a natural host of the human pathogen, we have previously demonstrated successful robotic infection of zebrafish embryos with M. tuberculosis and performed drug treatment of the infected larvae. In the present study, we examined for how long M. tuberculosis can be propagated in zebrafish larvae and tested a time series of infected larvae to study the transcriptional response via Illumina RNA deep sequencing (RNAseq). Bacterial aggregates carrying fluorescently labeled M. tuberculosis could be detected up to 9 days post-infection. The infected larvae showed a clear and specific transcriptional immune response with a high similarity to the inflammatory response of zebrafish larvae infected with the surrogate species M. marinum. We conclude that M. tuberculosis can be propagated in zebrafish larvae for at least one week after infection and provide further evidence that M. marinum is a good surrogate model for M. tuberculosis. The generated extensive transcriptome data sets will be of great use to add translational value to zebrafish as a model for infection of tuberculosis using the M. marinum infection system. In addition, we identify new marker genes such as dusp8 and CD180 that are induced by M. tuberculosis infection in zebrafish and in human macrophages at later stages of infection that can be further investigated.Peer reviewe

    Distribution and Acute Stressor-Induced Activation of Corticotrophin-Releasing Hormone Neurones in the Central Nervous System of Xenopus laevis

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    In mammals, corticotrophin-releasing hormone (CRH) and related peptides are known to play essential roles in the regulation of neuroendocrine, autonomic and behavioural responses to physical and emotional stress. In nonmammalian species, CRH-like peptides are hypothesized to play similar neuroendocrine and neurocrine roles. However, there is relatively little detailed information on the distribution of CRH neurones in the central nervous system (CNS) of nonmammalian vertebrates, and there are currently no comparative data on stress-induced changes in CRH neuronal physiology. We used a specific, affinity-purified antibody raised against synthetic Xenopus laevis CRH to map the distribution of CRH in the CNS of juvenile South African clawed frogs . We then analysed stress-induced changes in CRH immunoreactivity (CRH-ir) throughout the CNS. We found that CRH-positive cell bodies and fibres are widely distributed throughout the brain and rostral spinal cord of juvenile X. laevis . Strong CRH-immunoreactovity (ir) was found in cell bodies and fibres in the anterior preoptic area (POA, an area homologous to the mammalian paraventricular nucleus) and the external zone of the median eminence. Specific CRH-ir cell bodies and fibres were also identified in the septum, pallium and striatum in the telencephalon; the amygdala, bed nucleus of the stria terminalis and various hypothalamic and thalamic nuclei in the diencephalon; the tectum, torus semicircularis and tegmental nuclei of the mesencephalon; the cerebellum and locus coeruleus in the rhombencephalon; and the ventral horn of the rostral spinal cord. To determine if exposure to an acute physical stressor alters CRH neuronal physiology, we exposed juvenile frogs to shaking/handling and conducted morphometric analysis. Plasma corticosterone was significantly elevated by 30 min after exposure to the stressor and continued to increase up to 6 h. Morphometric analysis of CRH-ir after 4 h of stress showed a significant increase in CRH-ir in parvocellular neurones of the anterior preoptic area, the medial amygdala and the bed nucleus of the stria terminalis, but not in other brain regions. The stress-induced increase in CRH-ir in the POA was associated with increased Fos-like immunoreactivity (Fos-LI), and confocal microscopy showed that CRH-ir colocalized with Fos-LI in a subset of Fos-LI-positive neurones. Our results support the view that the basic pattern of CNS CRH expression arose early in vertebrate evolution and lend further support to earlier studies suggesting that amphibians may be a transitional species for descending CRH-ergic pathways. Furthermore, CRH neurones in the frog brain exhibit changes in response to a physical stressor that parallel those seen in mammals, and thus are likely to play an active role in mediating neuroendocrine, behavioural and autonomic stress responses.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73585/1/j.1365-2826.2004.01246.x.pd

    Economic Valuation of Water Buffering

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    The Bacillus stearothermophilus Mannitol Regulator, MtlR, of the Phosphotransferase System. A DNA-Binding Protein, Regulated by HPr and IICBmtl-Dependent Phosphorylation

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    D-Mannitol is taken up by Bacillus stearothermophilus and phosphorylated via a phosphoenolpyruvate-dependent phosphotransferase system (PTS). The genes involved in the mannitol uptake were recently cloned and sequenced. One of the genes codes for a putative transcriptional regulator, MtlR. The presence of a DNA binding helix-turn-helix motif and two antiterminator-like PTS regulation domains, suggest that MtlR is a DNA-binding protein, the activity of which can be regulated by phosphorylation by components of the PTS. To demonstrate DNA binding of MtlR to a region upstream of the mannitol promoter, by DNA footprinting, MtlR was overproduced and purified. EI, HPr, IIAmtl, and IICBmtl of B. stearothermophilus were purified and used to demonstrate that MtlR can be phosphorylated and regulated by HPr and IICBmtl, in vitro. Phosphorylation of MtlR by HPr increases the affinity of MtlR for its binding site, whereas phosphorylation by IICBmtl results in a reduction of this affinity. The differential effect of phosphorylation, by two different proteins, on the DNA binding properties of a bacterial transcriptional regulator has not, to our knowledge, been described before. Regulation of MtlR by two components of the PTS is an example of an elegant control system sensing both the presence of mannitol and the need to utilize this substrate.

    Transforming landscapes, transforming lives : the business of sustainable water buffer management

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    This book is about sustainable land management, the development of water buffers and the business case underneath it. It is part of the discussion on the green economy: investment in natural resource management makes business sense. This also applies for investment in land, water and vegetative cover. Some of the parameters may be different – returns may not always be immediate – but essentially both the financial payback and the economic dividend of investing in integrated landscapes – if done properly – are rewarding. The social impact moreover is important – investing in sustainable land and water buffers will transform lives and economies. Having a buffer gives a sense of security and the reassurance that come what may one’s livelihood is secured

    Transforming landscapes, transforming lives : the business of sustainable water buffer management

    No full text
    This book is about sustainable land management, the development of water buffers and the business case underneath it. It is part of the discussion on the green economy: investment in natural resource management makes business sense. This also applies for investment in land, water and vegetative cover. Some of the parameters may be different – returns may not always be immediate – but essentially both the financial payback and the economic dividend of investing in integrated landscapes – if done properly – are rewarding. The social impact moreover is important – investing in sustainable land and water buffers will transform lives and economies. Having a buffer gives a sense of security and the reassurance that come what may one’s livelihood is secured

    Long-term outcome and quality of life after initial and repeat resection of colorectal liver metastasis: A retrospective analysis

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    Background: Repeat hepatectomy is a widely accepted treatment for patients with recurrent colorectal liver metastasis (CRLM). The aim of this study was to compare initial and repeat hepatic resection concerning overall survival, prognostic factors and postoperative quality of life.Methods: Data on patients who underwent initial or repeat hepatic resection for CRLM between 2010 and 2016 were prospectively collected and retrospectively evaluated. Follow-up data, EORTC QLQ-C30 and QLQ-LMC21 questionnaire results for quality of life (QoL) evaluation were analyzed.Results: 160 patients at a median age of 62.8 +/- 11.8 years were analyzed. 122 were initially resected and 38 underwent a repeat hepatic resection. Disease-free survival (DSF) was superior in the initial resection group (p &lt;0.001), while there was no difference in overall survival (OS) (p = 0.288). BMI&gt; 30 (p = 0.012), extrahepatic tumor manifestation (p = 0.037),&gt; 1 CRLM manifestation (p = 0.009), and perioperative chemotherapy (p = 0.006) in the initial resection group and primary left colon tumor (p = 0.001) in the repeat resection group were identified as prognostic factors in multivariate Cox regression analysis. EORTC QLQ-LMC21 module symptom score displayed an increased occurrence of a dry mouth in the initial hepatectomy group (p = 0.003). EORTC QLQ-C30 general functioning and symptom scores showed no difference.Conclusion: Repeat hepatic resection for CRLM is as effective as primary surgical treatment in terms of OS and QoL. Patients should be selected carefully concerning prognostic factors as DFS is decreased after repeat hepatic resection.</p
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