A quantitative study of the orientation bias of some edge detector schemes

The evaluation of a particular set of edge detection schemes is described. The results obtained are compared with those obtained from an edge detection scheme using a texture oriented approach. The orientational bias of these schemes is emphasized. Improved qualitative observations are reported and a comparison of the evaluation method with another edge detection evaluation method is presented

Gene expression caused by alkylating agents and cis-diamminedichloroplatinum(II) in Escherichia coli

Previous work has demonstrated heterogeneous effects of methylating agents on induction of DNA damage inducible genes in Escherichia coli. These studies employed E. coli mutants that have fusions of the lac operon to genes induced by treatment with sublethal levels of alkylating agents. These mutants were selected from random insertions of the Mu-dl (Apr lac) phage by screening for induction of beta-galactosidase activity in the presence of methylmethanesulfonate or N-methyl-N\u27-nitro-N-nitrosoguanidine. The current report extends these findings by analyzing gene expression caused by mechlorethamine, chloroethylnitrosoureas and cis-diamminedichloroplatinum(II) (cis-DDP). The results demonstrate heterogeneous effects by these agents on gene expression. While 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea induces alkA, other nitrosoureas, mechlorethamine, and cis-DDP do not cause expression of this gene. Further, while all nitrosoureas caused expression of aidC, mechlorethamine and cis-DDP did not. Lastly, cis-DDP caused marked expression of a sulA fusion mutant while not inducing any of the other E. coli fusion mutants

Superconductivity from correlated hopping

We consider a chain described by a next-nearest-neighbor hopping combined with a nearest-neighbor spin flip. In two dimensions this three-body term arises from a mapping of the three-band Hubbard model for CuO$_2$ planes to a generalized $t-J$ model and for large O-O hopping favors resonance-valence-bond superconductivity of predominantly $d$-wave symmetry. Solving the ground state and low-energy excitations by analytical and numerical methods we find that the chain is a Luther-Emery liquid with correlation exponent $K_{\rho} = (2-n)^2/2$, where $n$ is the particle density.Comment: 10 pages, RevTeX 3.0 + 2 PostScript figs. Accepted for publication in Phys.Rev.

Theorising variation in engagement in professional and curriculum development: performativity, capital, systems and purpose

Increasingly, policymakers seek to improve the quality of teaching through curriculum innovations and continuing professional development (CPD) programmes. However, engagement by schools and teachers varies due to mediating influences of neoliberal policies. In this article, we contribute to understanding how these tendencies affect participation. Problematising the notion of context, we examine ways in which systemic influences interacted with participation in a government-funded mathematics professional and curriculum development programme and also with participants’ purposes. A 3-level clustered Randomised Controlled Trial (RCT) and an implementation and process evaluation were augmented by in-depth case studies, cross-case analysis and the application of theoretical constructs to interpret findings. Theories of capital, figured worlds and systemic coupling are utilised to theorise context. Different levels of engagement are partly explainable by: the interaction of schools' relative systemic advantage and disadvantage; their orientation and coupling to performativity regimes; and the alignment or dissonance between continuing professional development or change programmes and the pedagogical and CPD cultures and purposes of the ‘actors’ (schools, departments and teachers). Performativity concerns restricted what were considered legitimate outcomes in some case study schools. This depended on teachers and schools' positioning in terms of relative degrees of systemic privilege or disadvantage - understood as economic, cultural, social and symbolic capital - and also in terms of figured worlds and system coupling. The case studies provide insights into how collaborative professional learning can be fostered more productively. Methodologically, we demonstrate the power of combining methodologies and applying explanatory social theory to augment quasi-experimental paradigms

Miniature thermistor chain for determining surficial sediment porewater advection

A miniature thermistor chain (mTc) was developed to measure the subdiurnal variability of temperature in the upper layers of subtidal coastal permeable (sandy) sediments and across the sediment-water interface (SWI). The mTc has 15 precision thermistors (0.002°C accuracy) attached by narrow tines to a stainless steel backbone that connects to an electronics module, all of which is buried in the top 20 cm of the sediment. Instrument performance was tested by deploying the mTc in nearshore permeable sediment at the Kilo Nalu Observatory, Oahu, Hawaii over an 80-d period. The mTc reached thermal equilibrium with the adjoining sediment within a few days after deployment and then recorded the advective propagation of the sub-daily water-column temperature variation into the sediment. The data produced are consistent with predicted effects of surface waves on advective porewater transport: transport rate increased with wave height and decreased with depth below the SWI, and temperature time lag increased with depth below the SWI. Data from an independent, more deeply buried thermistor are in good agreement with the mTc time-series data, showing attenuated temperature variability and similar (but longer, as expected) thermal time lags. Because thermal variations in surficial sediments is dominated by advection in wavy environments, mTc subdiurnal temperature propagation data can be used to calculate advective transport across the SWI and as deep as 20 cm into the sediment (i.e., over depths where advection dominates over thermal diffusion).This is the publisher’s final pdf. The published article is copyrighted by the American Society of Limnology and Oceanography, Inc. and can be found at: http://aslo.org/lomethods/index.html

Managing lifestyle change to reduce coronary risk: a synthesis of qualitative research on peoples’ experiences

Background Coronary heart disease is an incurable condition. The only approach known to slow its progression is healthy lifestyle change and concordance with cardio-protective medicines. Few people fully succeed in these daily activities so potential health improvements are not fully realised. Little is known about peoples’ experiences of managing lifestyle change. The aim of this study was to synthesise qualitative research to explain how participants make lifestyle change after a cardiac event and explore this within the wider illness experience. Methods A qualitative synthesis was conducted drawing upon the principles of meta-ethnography. Qualitative studies were identified through a systematic search of 7 databases using explicit criteria. Key concepts were identified and translated across studies. Findings were discussed and diagrammed during a series of audiotaped meetings. Results The final synthesis is grounded in findings from 27 studies, with over 500 participants (56% male) across 8 countries. All participants experienced a change in their self-identity from what was ‘familiar’ to ‘unfamiliar’. The transition process involved ‘finding new limits and a life worth living’ , ‘finding support for self’ and ‘finding a new normal’. Analyses of these concepts led to the generation of a third order construct, namely an ongoing process of ‘reassessing past, present and future lives’ as participants considered their changed identity. Participants experienced a strong urge to get back to ‘normal’. Support from family and friends could enable or constrain life change and lifestyle changes. Lifestyle change was but one small part of a wider ‘life’ change that occurred. Conclusions The final synthesis presents an interpretation, not evident in the primary studies, of a person-centred model to explain how lifestyle change is situated within ‘wider’ life changes. The magnitude of individual responses to a changed health status varied. Participants experienced distress as their notion of self identity shifted and emotions that reflected the various stages of the grief process were evident in participants’ accounts. The process of self-managing lifestyle took place through experiential learning; the level of engagement with lifestyle change reflected an individual’s unique view of the balance needed to manage ‘realistic change’ whilst leading to a life that was perceived as ‘worth living’. Findings highlight the importance of providing person centred care that aligns with both psychological and physical dimensions of recovery which are inextricably linked

What young people report about the personal characteristics needed for social science research after carrying out their own investigations in an after-school club

Several arguments have been put forward about the benefits of young people carrying out their own social science research in terms of empowering their voices and their participation. Much less attention has been paid to investigating the understandings young people develop about the research process itself. Seven twelve-year-olds carried out self-directed social science research into a topic of their choice. Towards the end of their six months experience we used a questionnaire and follow-up semi-structured interviews to investigate, from a socio-cultural perspective, what the young people thought about being a researcher. Thematic analysis of the interviews identified three themes and eight subthemes suggesting that they were aware of: the need to demonstrate researcher/research integrity (be thorough, truthful, orderly, and have a good understanding of research process); the need for good interpersonal skills and standards; and good self-management skills (be resilient, agentic, committed, and good at time management). We discuss how first-hand social science research experience might: be relevant to several areas of schooling; give young people experience of the personal characteristics important for success; help young people to realise that they can be social science researchers, and offer advanced and novel learning experiences outside the constraints of the school curriculum

Programmable antivirals targeting critical conserved viral RNA secondary structures from influenza A virus and SARS-CoV-2

Influenza A virus’s (IAV’s) frequent genetic changes challenge vaccine strategies and engender resistance to current drugs. We sought to identify conserved and essential RNA secondary structures within IAV’s genome that are predicted to have greater constraints on mutation in response to therapeutic targeting. We identified and genetically validated an RNA structure (packaging stem–loop 2 (PSL2)) that mediates in vitro packaging and in vivo disease and is conserved across all known IAV isolates. A PSL2-targeting locked nucleic acid (LNA), administered 3 d after, or 14 d before, a lethal IAV inoculum provided 100% survival in mice, led to the development of strong immunity to rechallenge with a tenfold lethal inoculum, evaded attempts to select for resistance and retained full potency against neuraminidase inhibitor-resistant virus. Use of an analogous approach to target SARS-CoV-2, prophylactic administration of LNAs specific for highly conserved RNA structures in the viral genome, protected hamsters from efficient transmission of the SARS-CoV-2 USA_WA1/2020 variant. These findings highlight the potential applicability of this approach to any virus of interest via a process we term ‘programmable antivirals’, with implications for antiviral prophylaxis and post-exposure therapy