Contrast Mechanisms for the Detection of Ferroelectric Domains with Scanning Force Microscopy

We present a full analysis of the contrast mechanisms for the detection of ferroelectric domains on all faces of bulk single crystals using scanning force microscopy exemplified on hexagonally poled lithium niobate. The domain contrast can be attributed to three different mechanisms: i) the thickness change of the sample due to an out-of-plane piezoelectric response (standard piezoresponse force microscopy), ii) the lateral displacement of the sample surface due to an in-plane piezoresponse, and iii) the electrostatic tip-sample interaction at the domain boundaries caused by surface charges on the crystallographic y- and z-faces. A careful analysis of the movement of the cantilever with respect to its orientation relative to the crystallographic axes of the sample allows a clear attribution of the observed domain contrast to the driving forces respectively.Comment: 8 pages, 8 figure

An Evaluation Of Provision In A School Designated As Catering For Pupils Categorised As Having 'Emotional And Behavioural Difficulties' In The Light Of The Perspectives And Expectations Of Its Various Stakeholders

Line End is an 11-16 day school for pupils categorised as having emotional and behavioural difficulties (EBD). It is maintained by Farside Local Education Authority, and provides secondary education for pupils who are statemented as having emotional and behavioural difficulties. Some have additional learning difficulties, this assessment being based on reading ages that are considerably lower than their chronological ages, and scores in KS2 SATs that are below National averages. All referrals come through the local authority’s special educational needs department; invariably, the pupils who are placed at Line End either transfer from the EBD primary unit, or are those who have been excluded from mainstream secondary schools within the borough. The aim of the study is to establish the extent to which Line End is felt to be effective by its various stakeholders; and in establishing this position, it is first important to elicit the criteria by which the various stakeholders judge the school to be effective. The first phase of the study, therefore, is aimed at eliciting these stakeholder criteria, whilst the second phase focuses on the extent to which the school is perceived to be effective in its various areas of provision, based on these very criteria. A subsequent analysis of findings seeks to examine stakeholder perspectives, and the extent to which there is congruence and/or divergence of perspective amongst and between stakeholders might create conflict or tensions between and amongst stakeholders. Findings from the first phase of the study suggest that there is broad agreement amongst stakeholders about what should constitute effective provision for Line End pupils: addressing both academic and emotional/behavioural needs effectively, providing a safe and positive environment in which to make such provision, and providing opportunities for the reintegration of pupils to mainstream where appropriate and practicable. These three areas reflect the three major aims of the school as outlined in the staff handbook, and alongside these as key indicators of quality, stakeholders included relationships between home and school, and the management/organisation of the school -the extent to which it was strategically or ‘crisis’ managed. Findings from the second phase of the research suggested that the school was perceived to be effective by virtually all of its stakeholders - in some areas for some of the time. There were differences of perspective within stakeholder groups, and sometimes differences of emphasis between stakeholder groups. These differences did not necessarily lead to tension, as it was possible for differing perspectives to co-exist; the tensions became evident when perspectives conflicted rather than co-existed, as the group or individual who held the greatest power would invariably have its way in translating its perspective into policy and practic

Three-dimensionality of space and the quantum bit: an information-theoretic approach

It is sometimes pointed out as a curiosity that the state space of quantum two-level systems, i.e. the qubit, and actual physical space are both three-dimensional and Euclidean. In this paper, we suggest an information-theoretic analysis of this relationship, by proving a particular mathematical result: suppose that physics takes place in d spatial dimensions, and that some events happen probabilistically (not assuming quantum theory in any way). Furthermore, suppose there are systems that carry "minimal amounts of direction information", interacting via some continuous reversible time evolution. We prove that this uniquely determines spatial dimension d=3 and quantum theory on two qubits (including entanglement and unitary time evolution), and that it allows observers to infer local spatial geometry from probability measurements.Comment: 13 + 22 pages, 9 figures. v4: some clarifications, in particular in Section V / Appendix C (added Example 39

Land subsidence hazard in iran revealed by country-scale analysis of sentinel-1 insar

Many areas across Iran are subject to land subsidence, a sign of exceeding stress due to the over-extraction of groundwater during the past decades. This paper uses a huge dataset of Sentinel-1, acquired since 2014 in 66 image frames of 250×250km, to identify and monitor land subsidence across Iran. Using a two-step time series analysis, we first identify subsidence zones at a medium scale of 100m across the country. For the first time, our results provide a comprehensive nationwide map of subsidence in Iran and recognize its spatial distribution and magnitude. Then, in the second step of analysis, we quantify the deformation time series at the highest possible resolution to study its impact on civil infrastructure. The results spots the hazard posed by land subsidence to different infrastructure. Examples of road and railways affected by land subsidence hazard in Tehran and Mashhad, two of the most populated cities in Iran, are presented in this study

Exploring cloud-based platforms for rapid insar time series analysis

The idea of near real-time deformation analysis using Synthetic Aperture Radar (SAR) data as a response to natural and anthropogenic disasters has been an interesting topic in the last years. A major limiting factor for this purpose has been the non-availability of both spatially and temporally homogeneous SAR datasets. This has now been resolved thanks to the SAR data provided by the Sentinel-1A/B missions, freely available at a global scale via the Copernicus program of the European Space Agency (ESA). Efficient InSAR analysis in the era of Sentinel demands working with cloud-based platforms to tackle problems posed by large volumes of data. In this study, we explore a variety of existing cloud-based platforms for Multioral Interferometric SAR (MTI) analysis and discuss their opportunities and limitations

A comparison of HONO budgets for two measurement heights at a field station within the boreal forest in Finland

Peer reviewe

CMB lensing tomography with the DES Science Verification galaxies

We measure the cross-correlation between the galaxy density in the Dark Energy Survey (DES) Science Verification data and the lensing of the cosmic microwave background (CMB) as reconstructed with the Planck satellite and the South Pole Telescope (SPT). When using the DES main galaxy sample over the full redshift range 0.2 2sigma) detections in all bins. Comparing to the fiducial Planck cosmology, we find the redshift evolution of the signal matches expectations, although the amplitude is consistently lower than predicted across redshift bins. We test for possible systematics that could affect our result and find no evidence for significant contamination. Finally, we demonstrate how these measurements can be used to constrain the growth of structure across cosmic time. We find the data are fit by a model in which the amplitude of structure in the z< 1.2 universe is 0.73 ± 0.16 times as large as predicted in the Lambda cold dark matter Planck cosmology, a 1.7sigma deviation

Comparison of phenol red and polyethyleneglycol as nonabsorbable markers for the study of intestinal absorption in humans

When phenol red and polyethyleneglycol were used simultaneously as nonabsorbable markers in perfusion studies of the absorptive capacity of high jejunum in humans, apparent absorption was the same when calculated from either marker. This similar indication of dilution and of absorption by the two markers was found in normal subjects and in patients with nontropical sprue, whether aqueous or saline solutions of dextrose were infused. The similarity strengthens the evidence that either phenol red or polyethyleneglycol is a satisfactory “nonabsorbable” marker compound to indicate dilution in perfusion studies of dextrose and electrolyte absorption in limited segments of human intestine.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44368/1/10620_2005_Article_BF02233070.pd

Expression proteomics of UPF1 knockdown in HeLa cells reveals autoregulation of hnRNP A2/B1 mediated by alternative splicing resulting in nonsense-mediated mRNA decay

BACKGROUND: In addition to acting as an RNA quality control pathway, nonsense-mediated mRNA decay (NMD) plays roles in regulating normal gene expression. In particular, the extent to which alternative splicing is coupled to NMD and the roles of NMD in regulating uORF containing transcripts have been a matter of debate. RESULTS: In order to achieve a greater understanding of NMD regulated gene expression we used 2D-DiGE proteomics technology to examine the changes in protein expression induced in HeLa cells by UPF1 knockdown. QPCR based validation of the corresponding mRNAs, in response to both UPF1 knockdown and cycloheximide treatment, identified 17 bona fide NMD targets. Most of these were associated with bioinformatically predicted NMD activating features, predominantly upstream open reading frames (uORFs). Strikingly, however, the majority of transcripts up-regulated by UPF1 knockdown were either insensitive to, or even down-regulated by, cycloheximide treatment. Furthermore, the mRNA abundance of several down-regulated proteins failed to change upon UPF1 knockdown, indicating that UPF1`s role in regulating mRNA and protein abundance is more complex than previously appreciated. Among the bona fide NMD targets, we identified a highly conserved AS-NMD event within the 3` UTR of the HNRNPA2B1 gene. Overexpression of GFP tagged hnRNP A2 resulted in a decrease in endogenous hnRNP A2 and B1 mRNA with a concurrent increase in the NMD sensitive isoforms. CONCLUSIONS: Despite the large number of changes in protein expression upon UPF1 knockdown, a relatively small fraction of them can be directly attributed to the action of NMD on the corresponding mRNA. From amongst these we have identified a conserved AS-NMD event within HNRNPA2B1 that appears to mediate autoregulation of HNRNPA2B1 expression levels