Reading out a spatiotemporal population code by imaging neighbouring parallel fibre axons in vivo.

The spatiotemporal pattern of synaptic inputs to the dendritic tree is crucial for synaptic integration and plasticity. However, it is not known if input patterns driven by sensory stimuli are structured or random. Here we investigate the spatial patterning of synaptic inputs by directly monitoring presynaptic activity in the intact mouse brain on the micron scale. Using in vivo calcium imaging of multiple neighbouring cerebellar parallel fibre axons, we find evidence for clustered patterns of axonal activity during sensory processing. The clustered parallel fibre input we observe is ideally suited for driving dendritic spikes, postsynaptic calcium signalling, and synaptic plasticity in downstream Purkinje cells, and is thus likely to be a major feature of cerebellar function during sensory processing

Diagnosing and mapping pulmonary emphysema on X-ray projection images

To assess whether grating-based X-ray dark-field imaging can increase the sensitivity of X-ray projection images in the diagnosis of pulmonary emphysema and allow for a more accurate assessment of emphysema distribution. Lungs from three mice with pulmonary emphysema and three healthy mice were imaged ex vivo using a laser-driven compact synchrotron X-ray source. Median signal intensities of transmission (T), dark-field (V) and a combined parameter (normalized scatter) were compared between emphysema and control group. To determine the diagnostic value of each parameter in differentiating between healthy and emphysematous lung tissue, a receiver-operating-characteristic (ROC) curve analysis was performed both on a per-pixel and a per-individual basis. Parametric maps of emphysema distribution were generated using transmission, dark-field and normalized scatter signal and correlated with histopathology. Transmission values relative to water were higher for emphysematous lungs than for control lungs (1.11 vs. 1.06, p<0.001). There was no difference in median dark-field signal intensities between both groups (0.66 vs. 0.66). Median normalized scatter was significantly lower in the emphysematous lungs compared to controls (4.9 vs. 10.8, p<0.001), and was the best parameter for differentiation of healthy vs. emphysematous lung tissue. In a per-pixel analysis, the area under the ROC curve (AUC) for the normalized scatter value was significantly higher than for transmission (0.86 vs. 0.78, p<0.001) and dark-field value (0.86 vs. 0.52, p<0.001) alone. Normalized scatter showed very high sensitivity for a wide range of specificity values (94% sensitivity at 75% specificity). Using the normalized scatter signal to display the regional distribution of emphysema provides color-coded parametric maps, which show the best correlation with histopathology. In a murine model, the complementary information provided by X-ray transmission and dark-field images adds incremental diagnostic value in detecting pulmonary emphysema and visualizing its regional distribution as compared to conventional X-ray projections

The effect of waste disposal on soils in and around historic small towns

Soils in the urban environment are distinctive in that they are modified through waste amendments. Consideration has been given to how urban soil properties reflect current human influence; however, recent studies highlight their potential as historical archives. The impact of waste disposal on the nature, properties and formation of urban soils is significant, especially in historic small towns where the extent and complexity of refuse management practices is only just emerging. This study uses a multi-method approach to characterise and understand modes of urban anthrosol formation in three Scottish burghs; Lauder, Pittenweem and Wigtown. The objectives of this study are threefold; to establish the nature and diversity of urban anthrosols in and near to historic small towns, to characterise and account for the multiplicity of urban anthrosols in and near to historic small towns, and to elucidate the processes associated with waste management and disposal in historic small towns. Physical, chemical and micromorphological analysis of topsoil deposits indicate sustained addition of past waste materials to soils within and near to historic small towns. Soil characteristics were heterogeneous across burghs; however, distinct patterns according to past functional zones were identified. The burgh core and burgh acres are important areas of interest at all three burghs. Soil modification was most pronounced within burgh cores resulting in the formation of hortic horizons. Soils within burgh cores are characterised by neutral pH, increased organic matter content, enhanced magnetic susceptibility and elevated elemental concentrations such as calcium, phosphorus and potassium. In comparison the nature and extent of soil modification within burgh acres is more varied. At Lauder hortic soils were identified in the burgh acres suggesting pronounced soil modification through cultivation. Deepened topsoil in the burgh acres at Pittenweem provided evidence for application of mineral rich waste materials in the past. Moreover, magnetic and elemental enhancement (barium, phosphorus, lead, zinc) within the burgh acres south of Wigtown revealed historic soils based anthropogenic signal. It is argued that changes in soil characteristics at Lauder, Pittenweem and Wigtown can be explained through processes of waste management and disposal in the past. Evidence from micromorphological analyses suggests that waste in burgh cores typically comprised domestic waste, animal waste, building materials and fuel residues. These materials were also identified within burgh acres, although it is noted that their abundances were significantly lower. Variation in urban anthrosol characteristics between burghs is attributed to differing industries and patterns of resource exploitation, for example marine waste associated with fishing was only identified in coastal burghs. The sustained addition of waste materials to soils within and near to historic small towns was an effective waste management strategy. Waste disposal in burgh cores was likely to be a combination of direct application and midden spreading in back gardens. This led to enhanced soil fertility which was important in the development of urban horticulture; particularly for poorer inhabitants who did not have access to arable farm land adjacent to the burgh. Dunghills acted as temporary stores of waste in the main thoroughfares of Lauder, Pittenweem and Wigtown. These dunghills were systematically transported to the burgh acres for further use as a fertiliser; hence, an early form of urban composting. Processes of waste disposal could not be deduced from soil characteristics alone; however, likely methods include direct waste deposition, storage and redistribution of midden waste, and storage and redistribution of dunghills. The limitations of soil classification systems and mapping are highlighted, for example urban soils are either omitted from soil maps or are misclassified. It is recommended that urban soils in historic towns should be incorporated into future regional soil maps. Urban soils represent a complex archive of past human behaviour not necessarily reflected in archaeological excavation or documentary analysis. It is argued that soil and artefacts are equally important, hence soil should be a consideration in urban heritage and conservation strategies

Photometry of the Globular Cluster NGC 5466: Red Giants and Blue Stragglers

We present wide-field BVI photometry for about 11,500 stars in the low-metallicity cluster NGC 5466. We have detected the red giant branch bump for the first time, although it is at least 0.2 mag fainter than expected relative to the turnoff. The number of red giants (relative to main sequence turnoff stars) is in excellent agreement with stellar models from the Yonsei-Yale and Teramo groups, and slightly high compared to Victoria-Regina models. This adds to evidence that an abnormally large ratio of red giant to main-sequence stars is not correlated with cluster metallicity. We discuss theoretical predictions from different research groups and find that the inclusion or exclusion of helium diffusion and strong limit Coulomb interactions may be partly responsible. We also examine indicators of dynamical history: the mass function exponent and the blue straggler frequency. NGC 5466 has a very shallow mass function, consistent with large mass loss and recently-discovered tidal tails. The blue straggler sample is significantly more centrally concentrated than the HB or RGB stars. We see no evidence of an upturn in the blue straggler frequency at large distances from the center. Dynamical friction timescales indicate that the stragglers should be more concentrated if the cluster's present density structure has existed for most of its history. NGC 5466 also has an unusually low central density compared to clusters of similar luminosity. In spite of this, the specific frequency of blue stragglers that puts it right on the frequency -- cluster M_V relation observed for other clusters.Comment: 51 pages, 21 figures, 1 electronic table, accepted to Ap

Extraction of Morphological Features of Malaysian Rice Seed Varieties Using Flatbed Scanner

A high quality cultivated rice seeds are very important for Malaysian paddy industry to ensure a high yield of paddy production. Certified seeds that are mixed with other varieties and unwanted seeds such as weedy rice are considered as poor quality and faced rejection during a quality inspection by the Department of Agriculture. To ensure the seeds are cleaned from any foreign seeds, it is very important to develop a low cost and simple mechanism to classify the seeds according to its varieties. The use of a flatbed scanner is one of the alternative techniques for image acquisition of the seeds varieties. This study was carried out to evaluate morphological features of local rice seed varieties developed for Malaysian rice industry using image processing techniques. Image of four seed varieties, mainly are MR219, MR220, MR263, and MR269 were acquired and extracted using a normal desktop flatbed scanner. A LabVIEW program was developed to extract four main morphology features which are length, width, aspect ratio and rectangular aspect ratio. The extracted data were analysed in terms of its spread and variability. One-way ANOVA was done to compare the means of the morphological features. Further t-test analyses were done to distinguish between two seed varieties based on the variation in the morphological features of the seed kernel. The results indicated that seed length parameter extracted from the image acquired by the flatbed scanner is significant to differentiate the cultivated rice seed except for MR269 and MR220. Seed width can be used as a parameter to distinguish MR269 and MR220 pair. Thus, a combination of morphological parameters is necessary to classify the cultivated rice seed

Monte Carlo-based Noise Compensation in Coil Intensity Corrected Endorectal MRI

Background: Prostate cancer is one of the most common forms of cancer found in males making early diagnosis important. Magnetic resonance imaging (MRI) has been useful in visualizing and localizing tumor candidates and with the use of endorectal coils (ERC), the signal-to-noise ratio (SNR) can be improved. The coils introduce intensity inhomogeneities and the surface coil intensity correction built into MRI scanners is used to reduce these inhomogeneities. However, the correction typically performed at the MRI scanner level leads to noise amplification and noise level variations. Methods: In this study, we introduce a new Monte Carlo-based noise compensation approach for coil intensity corrected endorectal MRI which allows for effective noise compensation and preservation of details within the prostate. The approach accounts for the ERC SNR profile via a spatially-adaptive noise model for correcting non-stationary noise variations. Such a method is useful particularly for improving the image quality of coil intensity corrected endorectal MRI data performed at the MRI scanner level and when the original raw data is not available. Results: SNR and contrast-to-noise ratio (CNR) analysis in patient experiments demonstrate an average improvement of 11.7 dB and 11.2 dB respectively over uncorrected endorectal MRI, and provides strong performance when compared to existing approaches. Conclusions: A new noise compensation method was developed for the purpose of improving the quality of coil intensity corrected endorectal MRI data performed at the MRI scanner level. We illustrate that promising noise compensation performance can be achieved for the proposed approach, which is particularly important for processing coil intensity corrected endorectal MRI data performed at the MRI scanner level and when the original raw data is not available.Comment: 23 page