6,526 research outputs found
Risk management for drinking water safety in low and middle income countries: cultural influences on water safety plan (WSP) implementation in urban water utilities
We investigated cultural influences on the implementation of water safety plans (WSPs) using case studies from WSP pilots in India, Uganda and Jamaica. A comprehensive thematic analysis of semi-structured interviews (n = 150 utility customers, n = 32 WSP ‘implementers’ and n = 9 WSP ‘promoters’), field observations and related documents revealed 12 cultural themes, offered as ‘enabling’, ‘limiting’, or ‘neutral’, that influence WSP implementation in urban water utilities to varying extents. Aspects such as a ‘deliver first, safety later’ mind set; supply system knowledge management and storage practices; and non-compliance are deemed influential. Emergent themes of cultural influence (ET1 to ET12) are discussed by reference to the risk management, development studies and institutional culture literatures; by reference to their positive, negative or neutral influence on WSP implementation. The results have implications for the utility endorsement of WSPs, for the impact of organisational cultures on WSP implementation; for the scale-up of pilot studies; and they support repeated calls from practitioner communities for cultural attentiveness during WSP design. Findings on organisational cultures mirror those from utilities in higher income nations implementing WSPs – leadership, advocacy among promoters and customers (not just implementers) and purposeful knowledge management are critical to WSP success
Foot and Mouth Epidemic Reduces Cases of Human Cryptosporidiosis in Scotland.
In Scotland, rates of cryptosporidiosis infection in humans peak during the spring, a peak that is coincident with the peak in rates of infection in farm animals (during lambing and calving time). Here we show that, during the outbreak of foot and mouth disease (FMD) in 2001, there was a significant reduction in human cases of cryptosporidiosis infection in southern Scotland, where FMD was present, whereas, in the rest of Scotland, there was a reduction in cases that was not significant. We associate the reduction in human cases of cryptosporidiosis infection with the reduction in the number of young farm animals, together with restrictions on movement of both farm animals and humans, during the outbreak of FMD in 2001. We further show that, during 2002, there was recovery in the rate of cryptosporidiosis infection in humans throughout Scotland, particularly in the FMD-infected area, but that rates of infection remained lower, though not significantly, than pre-2001 levels
A model for tetrapyrrole synthesis as the primary mechanism for plastid-to-nucleus signaling during chloroplast biogenesis.
Chloroplast biogenesis involves the co-ordinated expression of the chloroplast and nuclear genomes, requiring information to be sent from the developing chloroplasts to the nucleus. This is achieved through retrograde signaling pathways and can be demonstrated experimentally using the photobleaching herbicide, norflurazon, which in seedlings results in chloroplast damage and the reduced expression of many photosynthesis-related, nuclear genes. Genetic analysis of this pathway points to a major role for tetrapyrrole synthesis in retrograde signaling, as well as a strong interaction with light signaling pathways. Currently, the best model to explain the genetic data is that a specific heme pool generated by flux through ferrochelatase-1 functions as a positive signal to promote the expression of genes required for chloroplast development. We propose that this heme-related signal is the primary positive signal during chloroplast biogenesis, and that treatments and mutations affecting chloroplast transcription, RNA editing, translation, or protein import all impact on the synthesis and/or processing of this signal. A positive signal is consistent with the need to provide information on chloroplast status at all times. We further propose that GUN1 normally serves to restrict the production of the heme signal. In addition to a positive signal re-enforcing chloroplast development under normal conditions, aberrant chloroplast development may produce a negative signal due to accumulation of unbound chlorophyll biosynthesis intermediates, such as Mg-porphyrins. Under these conditions a rapid shut-down of tetrapyrrole synthesis is required. We propose that accumulation of these intermediates results in a rapid light-dependent inhibition of nuclear gene expression that is most likely mediated via singlet oxygen generated by photo-excitation of Mg-porphyrins. Thus, the tetrapyrrole pathway may provide both positive and inhibitory signals to control expression of nuclear genes
An evaluation of fixation methods: Spatial and compositional cellular changes observed by Raman imaging
AbstractAlthough live cell imaging is desirable, it is not always feasible and in many situations cells are fixed in order to provide a ‘snapshot’ of the nature and distribution of molecules within a cell while minimising changes from cell movement, sample degradation etc. There is a wide range of fixation methods available that act via different mechanisms, and on different cell components. Each method has advantages and disadvantages and a choice of what fixation method to choose for a particular experiment needs to take these factors into consideration. Here we used Raman spectroscopic imaging of live cells, and compared with cells preserved with aldehyde, or organic solvent-based fixation methods to assess the chemical changes induced by each fixative, and their impact on the quality of images that can be obtained from fixed cells. Overall, aldehyde fixation methods performed significantly better than organic solvents with less severe loss of biochemical information. Aldehyde based fixatives show an altered biochemical content of the cells, attributed to adduct formation, but this can be minimised by optimising fixation temperature, or through removal of adduct formation by detergent-based permeabilization treatments as a second step (at the cost of the loss of other biochemical information). The results showed that organic solvents, on the other hand, lead to a severe loss of cell content, attributed to the loss of membrane integrity after the removal of lipids. Additionally, fixation with aldehydes prior to permeabilization with organic solvents does not provide adequate protection of cytoplasmic content. The use of Raman imaging is ideal for comparing groups of cells in terms of their molecular content, and the results show that aldehyde fixations methods are preferable for studies where the overall molecular content of the samples is important. Although there is no universal fixation method for every application, the results here allow us to provide a few general principles: where spectral similarity to live cells is important, fixation with paraformaldehyde at room temperature is preferable, at the cost of some blebbing and vacuole formation. Where preservation of cellular structure or biomolecular distribution is important, a mix of paraformaldehyde and glutaraldehyde would be more appropriate, but at the cost of some changes to spectral profile, particularly in DNA-related bands
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An idealized study of coupled atmosphere-ocean 4D-Var in the presence of model error
Atmosphere only and ocean only variational data assimilation (DA) schemes are able to use window lengths that are optimal for the error growth rate, non-linearity and observation density of the respective systems. Typical window lengths are 6-12 hours for the atmosphere and 2-10 days for the ocean. However, in the implementation of coupled DA schemes it has been necessary to match the window length of the ocean to that of the atmosphere, which may potentially sacrifice the accuracy of the ocean analysis in order to provide a more balanced coupled state. This paper investigates how extending the window length in the presence of model error affects both the analysis of the coupled state and the initialized forecast when using coupled DA with differing degrees of coupling.
Results are illustrated using an idealized single column model of the coupled atmosphere-ocean system. It is found that the analysis error from an uncoupled DA scheme can be smaller than that from a coupled analysis at the initial time, due to faster error growth in the coupled system. However, this does not necessarily lead to a more accurate forecast due to imbalances in the coupled state. Instead coupled DA is more able to update the initial state to reduce the impact of the model error on the accuracy of the forecast. The effect of model error is potentially most detrimental in the weakly coupled formulation due to the inconsistency between the coupled model used in the outer loop and uncoupled models used in the inner loop
Shifts in mid- to late-Holocene anion composition in Elk Lake (Grant County, Minnesota): Comparison of diatom and ostracode inferences
The fossil diatom record from Elk Lake (Grant County, Minnesota) was used to reconstruct salinity and brine type between 2640 and 4645 14C yr BP. This lake was selected for a brine-type reconstruction because a previous study using fossil-ostracode assemblages indicated a shift in anion composition during the mid-Holocene (Smith et al., 1997). Salinity was reconstructed using a transfer function developed for the Northern Great Plains (NGP) of North America; the reconstruction revealed that salinity was higher (1.5–6.2 g l−1) between ~4000 and 4645 14C yr BP and dropped to 0.35–1.2 g l−1 after 4000 14C yr BP. The anion composition of the system was investigated by passively plotting fossil diatom assemblages onto a canonical correspondence analysis (CCA) biplot of the NGP modern samples to determine where core assemblages fell with respect to brine type. The biplot suggests that Elk Lake was mainly a bicarbonate system, but temporarily shifted to sulfate domination at 4080 14C yr BP. Both the salinity and brine-type reconstructions essentially agree with results from Smith et al. (1997), but the diatom record provides less-definitive information on anion proportions as compared to anion concentrations. Because shifts in the relative abundances of anion-associated diatom taxa generally tracked the ostracode-inferred changes in brine type, we conclude that fossil diatom assemblages can reveal information on shifts in brine type over time and provide insight into brine evolution and groundwater behavior in a lake system
Operationalising factors that explain the emergence of infectious diseases : A case study of the human campylobacteriosis epidemic
Peer reviewedPublisher PD
Meta-proteomics of rumen microbiota indicates niche compartmentalisation and functional dominance in a limited number of metabolic pathways between abundant bacteria
An Engineered Community Approach for Industrial Cultivation of Microalgae.
Although no species lives in isolation in nature, efforts to grow organisms for use in biotechnology have generally focused on a single-species approach, particularly where a product is required at high purity. In such scenarios, preventing the establishment of contaminants requires considerable effort that is economically justified. However, for some applications in biotechnology where the focus is on lower-margin biofuel production, axenic culture is not necessary, provided yields of the desired strain are unaffected by contaminants. In this article, we review what is known about interspecific interactions of natural algal communities, the dynamics of which are likely to parallel contamination in industrial systems. Furthermore, we discuss the opportunities to improve both yields and the stability of cultures by growing algae in multi-species consortia.EK acknowledges funding from the FP7 DEMA project (Reference number 309086). ASR received funding from the People Programme (Marie Curie Actions) of the European Union's Seventh Framework Programme FP7/2007-2013/ under REA grant agreement n° 317184.This is the accepted manuscript. This is a copy of an article published in Industrial Biotechnology © 2014 [copyright Mary Ann Liebert, Inc.]; Industrial Biotechnology is available online at: http://online.liebertpub.com
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