The development of Northumbria University collections, materials and conservation research archive

This paper discusses issues that are common to conservation archive collections in the UK. It focusses on Northumbria University, where a significant number of artworks on canvas and paper, diaries, sketchbooks, artist materials, technological and scientific outputs, reconstructions, samples, photographs and digital images have been amassed over several decades in support of education and research. Although this resource is available to students and scholars, physical access is impeded by the diversity of locations where each item is held and the dependencies retrieval and supervision has on staff time. Our concern is that this valuable resource is underused because of the lack of electronic records, and whilst a few noteworthy artworks and materials are internally recorded, none are linked to heritage or educational networks. We anticipate that Northumbria is just one amongst many organisations with similar issues and that it is possible to plan for a more unified system where conservation archives and related research outputs are linked to a wider network

Modern machine–made washi and the implications for contemporary conservation practice

Japanese paper, commonly known as washi, is an important commercial commodity and intrinsic to both Western and Eastern conservation techniques due to its strength, transparency and excellent ageing properties. With modern technology and the slow decline in hand-made papermaking, much of the paper produced in Japan today is machine made-essentially a hybrid of traditional Asian techniques and European influences. How this paper is made and the materials used in its construction are often a closely guarded secret for obvious commercial reasons. Newly developed sizing agents, chemical treatments and the substitution of high quality bast fibres for inferior wood furnishes, are a concern for the conservation profession in regards to possible changes to the papers long- term behaviour, and immediate physical alterations due to the fibres strong orientation towards the machine-grain direction. The article collates and compares the materials and methods used in producing hand and machine-made washi and considers the potential risks and benefits resulting from current innovations. The study goes into the heart of paper production and distribution in Japan and as a consequence provides new knowledge to Western audiences. It also serves to clarify certain key technical terms which are currently open to a wide variety of interpretations

Rewinding the waves: tracking underwater signals to their source

Analysis of data, recorded on March 8th 2014 at the Comprehensive Nuclear-Test-Ban Treaty Organisation’s hydroacoustic stations off Cape Leeuwin Western Australia, and at Diego Garcia, reveal unique pressure signatures that could be associated with objects impacting at the sea surface, such as falling meteorites, or the missing Malaysian Aeroplane MH370. To examine the recorded signatures, we carried out experiments with spheres impacting at the surface of a water tank, where we observed almost identical pressure signature structures. While the pressure structure is unique to impacting objects, the evolution of the radiated acoustic waves carries information on the source. Employing acoustic–gravity wave theory we present an analytical inverse method to retrieve the impact time and location. The solution was validated using field observations of recent earthquakes, where we were able to calculate the eruption time and location to a satisfactory degree of accuracy. Moreover, numerical validations confirm an error below 0.02% for events at relatively large distances of over 1000 km. The method can be developed to calculate other essential properties such as impact duration and geometry. Besides impacting objects and earthquakes, the method could help in identifying the location of underwater explosions and landslides

Experimental evolution reveals high insecticide tolerance in Daphnia inhabiting farmland ponds

Exposure of nontarget populations to agricultural chemicals is an important aspect of global change. We quantified the capacity of natural Daphnia magna populations to locally adapt to insecticide exposure through a selection experiment involving carbaryl exposure and a control. Carbaryl tolerance after selection under carbaryl exposure did not increase significantly compared to the tolerance of the original field populations. However, there was evolution of a decreased tolerance in the control experimental populations compared to the original field populations. The magnitude of this decrease was positively correlated with land use intensity in the neighbourhood of the ponds from which the original populations were sampled. The genetic change in carbaryl tolerance in the control rather than in the carbaryl treatment suggests widespread selection for insecticide tolerance in the field associated with land use intensity and suggests that this evolution comes at a cost. Our data suggest a strong impact of current agricultural land use on nontarget natural Daphnia populations

Modelling and upscaling of transport in carbonates during dissolution: validation and calibration with NMR experiments

We present an experimental and numerical study of transport in carbonates during dissolution and its upscaling from the pore (∼ μm) to core (∼ cm) scale. For the experimental part, we use nuclear magnetic resonance (NMR) to probe molecular displacements (propagators) of an aqueous hydrochloric acid (HCl) solution through a Ketton limestone core. A series of propagator profiles are obtained at a large number of spatial points along the core at multiple time-steps during dissolution. For the numerical part, first, the transport model—a particle-tracking method based on Continuous Time Random Walks (CTRW) by Rhodes et al. (2008)—is validated at the pore scale by matching to the NMR-measured propagators in a beadpack, Bentheimer sandstone, and Portland carbonate Scheven et al. (2005). It was found that the emerging distribution of particle transit times in these samples can be approximated satisfactorily using the power law function ψ(t) ∼ t −1 −β, where 0 < β < 2. Next, the evolution of the propagators during reaction is modelled: at the pore scale, the experimental data is used to calibrate the CTRW parameters; then the shape of the propagators is predicted at later observation times. Finally, a numerical upscaling technique is employed to obtain CTRW parameters for the core. From the NMR-measured propagators, an increasing frequency of displacements in stagnant regions was apparent as the reaction progressed. The present model predicts that non-Fickian behaviour exhibited at the pore scale persists on the centimetre scale

Altered excitatory-inhibitory balance within somatosensory cortex is associated with enhanced plasticity and pain sensitivity in a mouse model of multiple sclerosis

S1 IHC in pre-symptomatic and clinical-onset EAE: PV+ cell counts, PNN counts, and Iba-1+ microglia counts. A) Representative fluorescence photomicrographs of PV+ staining (low-mag) in S1 from control (CFA) and EAE animals at the pre-symptomatic stage (7–9 dpi PRE) or clinical onset (ONS). B) Group mean (±S.E.) total PV+ cell counts from S1HL of CFA (n = 8), PRE (n = 4), and ONS (n = 4) EAE animals. No significant differences were observed between groups (one-way ANOVA N.S.). C) Representative fluorescence photomicrographs of WFA+ staining (PNNs) in S1 from control (CFA) and EAE animals at the pre-symptomatic stage (7–9 dpi PRE) or clinical onset (ONS). D) Group mean (±S.E.) total PNN counts from S1HL of CFA (n = 11), PRE (n = 4), and ONS (n = 8) EAE animals. EAE animals exhibited significantly reduced PNN-counts vs. CFA-controls at clinical onset (one-way ANOVA, p = 0.007, post hoc comparisons vs. CFA-controls by Dunnett’s method). E) Representative fluorescence photomicrographs of Iba-1+ staining (PNNs) in S1 from control (CFA) and EAE animals at the pre-symptomatic stage (7–9 dpi PRE) or clinical onset (ONS). F) Group mean (±S.E.) total Iba-1+ counts from S1HL of CFA (n = 13), PRE (n = 4), and ONS (n = 8) EAE animals. EAE animals exhibited significantly increased numbers of Iba-1+ cells (microglial activation) in S1HL vs. CFA-controls at all time points (one-way ANOVA, p = 0.012, post hoc comparisons vs. CFA-controls by Dunnett’s method). (PDF 6418 kb

Pattern of DNA methylation in daphnia : evolutionary perspective

DNA methylation is an evolutionary ancient epigenetic modification that is phylogenetically widespread. Comparative studies of the methylome across a diverse range of non-conventional and conventional model organisms is expected to help reveal how the landscape of DNA methylation and its functions have evolved. Here, we explore the DNA methylation profile of two species of the crustacean Daphnia using whole genome bisulfite sequencing. We then compare our data with the methylomes of two insects and two mammals to achieve a better understanding of the function of DNA methylation in Daphnia. Using RNA-sequencing data for all six species, we investigate the correlation between DNA methylation and gene expression. DNA methylation in Daphnia is mainly enriched within the coding regions of genes, with the highest methylation levels observed at exons 2-4. In contrast, vertebrate genomes are globally methylated, and increase towards the highest methylation levels observed at exon 2, and maintained across the rest of the gene body. Although DNA methylation patterns differ among all species, their methylation profiles share a bimodal distribution across the genomes. Genes with low levels of CpG methylation and gene expression are mainly enriched for species specific genes. In contrast, genes associated with high methylated CpG sites are highly transcribed and evolutionary conserved across all species. Finally, the positive correlation between internal exons and gene expression potentially points to an evolutionary conserved mechanism, whereas the negative regulation of gene expression via methylation of promoters and exon 1 is potentially a secondary mechanism that has been evolved in vertebrates