1,219 research outputs found
Coverage as a misleading development goal: the concept of water-person-years
Large sums of money have been poured into developing countries by donors, aid agencies and NGOs to
improve people’s access to water. However, many of the constructed water sources have broken down or
are dysfunctional. At the same time, donors, governments and NGOs rush to achieve coverage targets,
ambitiously set and inaccurately measured. This paper proposes a new way of measuring the impact of
investments. Assessing investments in “waterpersonyears”
over a defined period of time, allows for a
more efficient allocation of resources, and calls for a rethinking of the current development approach.
Measuring in waterpersonyears
is necessary in order to shift focus from new infrastructure
development to operation and maintenance of existing water systems, something that is crucial for
sustainability
Live monitoring of rural drinking water schemes using mobile phone infrastructure
Post-installation
monitoring of rural drinking water projects is costly and time consuming, but at the
same time a necessity to ensure a project’s sustainability. Limited financial and human resources restrain
the level at which facilitators can follow up on their projects, leaving them with little up to date
information. The recent mobile phone revolution in Africa has drastically improved the qualitative
information flow between remote project sites and facilitators. The solution presented here uses the same
technology to improve the quantitative information flow. A specially developed solar powered unit, with a
built in GSMmodem,
collects daily data about sales, expenditures and production from the water
committee which is operating the system. The data is instantly transmitted and presented to the facilitator
by a web interface and any unexpected variations will alert the facilitator, allowing for a swift reaction
Replication and extension of rapid decompression of chimpanzees to a near vacuum
Decompression of chimpanzees to near vacuum and recover
Scanning Electron Microscopy in the Evaluation of Consolidation Treatments for Stone
The use of scanning electron microscopy (SEM) examination is shown to be an important tool in the evaluation of the effectiveness of consolidant treatments in stone. This implies the visualization of the attachment of the resin to the stone, the assessment of the degree of penetration and the distribution of the resin in the stone matrix. These factors can then be correlated with the chemical nature of the stone and the resin.
A sample preparation technique for limestone, based on acid etching of the surface, is described. This technique improves the visualization of the resin within the stone
Engineering the Drosophila Genome for Developmental Biology.
The recent development of transposon and CRISPR-Cas9-based tools for manipulating the fly genome in vivo promises tremendous progress in our ability to study developmental processes. Tools for introducing tags into genes at their endogenous genomic loci facilitate imaging or biochemistry approaches at the cellular or subcellular levels. Similarly, the ability to make specific alterations to the genome sequence allows much more precise genetic control to address questions of gene function.BBSRC BB/L002817/1 and BB/N007069/
Absence of an embryonic stem cell DNA methylation signature in human cancer.
BackgroundDifferentiated cells that arise from stem cells in early development contain DNA methylation features that provide a memory trace of their fetal cell origin (FCO). The FCO signature was developed to estimate the proportion of cells in a mixture of cell types that are of fetal origin and are reminiscent of embryonic stem cell lineage. Here we implemented the FCO signature estimation method to compare the fraction of cells with the FCO signature in tumor tissues and their corresponding nontumor normal tissues.MethodsWe applied our FCO algorithm to discovery data sets obtained from The Cancer Genome Atlas (TCGA) and replication data sets obtained from the Gene Expression Omnibus (GEO) data repository. Wilcoxon rank sum tests, linear regression models with adjustments for potential confounders and non-parametric randomization-based tests were used to test the association of FCO proportion between tumor tissues and nontumor normal tissues. P-values of < 0.05 were considered statistically significant.ResultsAcross 20 different tumor types we observed a consistently lower FCO signature in tumor tissues compared with nontumor normal tissues, with 18 observed to have significantly lower FCO fractions in tumor tissue (total n = 6,795 tumor, n = 922 nontumor, P < 0.05). We replicated our findings in 15 tumor types using data from independent subjects in 15 publicly available data sets (total n = 740 tumor, n = 424 nontumor, P < 0.05).ConclusionsThe results suggest that cancer development itself is substantially devoid of recapitulation of normal embryologic processes. Our results emphasize the distinction between DNA methylation in normal tightly regulated stem cell driven differentiation and cancer stem cell reprogramming that involves altered methylation in the service of great cell heterogeneity and plasticity
Transcriptionally active chromatin loops contain both ‘active’ and ‘inactive’ histone modifications that exhibit exclusivity at the level of nucleosome clusters
Chromatin state is thought to impart regulatory function to the underlying DNA sequence. This can be established through histone modifications and chromatin organisation, but exactly how these factors relate to one another to regulate gene expression is unclear. In this study, we have used super-resolution microscopy to image the Y loops of Drosophila melanogaster primary spermatocytes, which are enormous transcriptionally active chromatin fibres, each representing single transcription units that are individually resolvable in the nuclear interior. We previously found that the Y loops consist of regular clusters of nucleosomes, with an estimated median of 54 nucleosomes per cluster with wide variation. In this study, we report that the histone modifications H3K4me3, H3K27me3, and H3K36me3 are also clustered along the Y loops, with H3K4me3 more associated with diffuse chromatin compared to H3K27me3. These histone modifications form domains that can be stretches of Y loop chromatin micrometres long, or can be in short alternating domains. The different histone modifications are associated with different sizes of chromatin clusters and unique morphologies. Strikingly, a single chromatin cluster almost always only contains only one type of the histone modifications that were labelled, suggesting exclusivity, and therefore regulation at the level of individual chromatin clusters. The active mark H3K36me3 is more associated with actively elongating RNA polymerase II than H3K27me3, with polymerase often appearing on what are assumed to be looping regions on the periphery of chromatin clusters. These results provide a foundation for understanding the relationship between chromatin state, chromatin organisation, and transcription regulation – with potential implications for pause-release dynamics, splicing complex organisation and chromatin dynamics during polymerase progression along a gene
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