Ferroelectrically induced weak-ferromagnetism in a single-phase multiferroic by design

We present a strategy to design structures for which a polar lattice distortion induces weak ferromagnetism. We identify a large class of multiferroic oxides as potential realizations and use density-functional theory to screen several promising candidates. By elucidating the interplay between the polarization and the Dzyaloshinskii-Moriya vector, we show how the direction of the magnetization can be switched between 180$^{\circ}$ symmetry equivalent states with an applied electric field.Comment: Significantly revised for clarit

Epitaxial-strain-induced multiferroicity in SrMnO3_{3} from first principles

First-principles density-functional calculations reveal a large spin-phonon coupling in cubic SrMnO$_{3}$, with ferromagnetic ordering producing a polar instability. Through combination of this coupling with the strain-polarization coupling characteristic of perovskites, the bulk antiferromagnetic paraelectric ground state of SrMnO$_3$ is shown to be driven to a previously unreported multiferroic ferroelectric-ferromagnetic state by increasing epitaxial strain, both tensile and compressive. This state has a computed polarization and estimated Curie temperature above 54 $\mu$C/cm$^2$ and 92 K. Large mixed magnetic-electric-elastic responses are predicted in the vicinity of the phase boundaries.Comment: 5 pages, 2 figures, 1 tabl

Frustrated classical Heisenberg model in 1 dimension with added nearest-neighbor biquadratic exchange interactions

The ground state phase diagram is determined for the frustrated classical Heisenberg chain with added nearest-neighbor biquadratic exchange interactions. There appear ferromagnetic, incommensurate-spiral, and up-up-down-down phases; a lock-in transition occurs at the spiral boundary. The model contains an isotropic version of the ANNNI model; it is also closely related to a model proposed for some manganites. The Luttinger-Tisza method is not obviously useful due to the non-linear weak-constraint problem; however the ground state is obtained analytically by the exact cluster method of Lyons and Kaplan. The results are compared to the model of Thorpe and Blume, where the Heisenberg part of the energy is not frustrated.Comment: 4 pages, 3 figure

Strain induced half-metal to semiconductor transition in GdN

We have investigated the electronic structure and magnetic properties of GdN as a function of unit cell volume. Based on the first-principles calculations of GdN, we observe that there is a transformation in conduction properties associated with the volume increase: first from halfmetallic to semi-metallic, then ultimately to semiconducting. We show that applying stress can alter the carrier concentration as well as mobility of the holes and electrons in the majority spin channel. In addition, we found that the exchange parameters depend strongly on lattice constant, thus the Curie temperature of this system can be enhanced by applying stress or doping impurities.Comment: 9 pages, 3 figure

DESIGN, FABRICATION AND PERFORMANCE EVALUATION OF A RICE DESTONING MACHINE

Rice cleaning and separation has not received adequate attention in Nigeria, thus making the consumption of our locally grown rice unacceptable. These processes do not actually give the best of rice grain as some impurities and various types of contaminations of undesirable matter accompanied the rice grains. The general objective of the work is to design, fabricate and carry out the performance evaluation of a rice destoner. The destoner consists of the reciprocating and vibrating sieves. The machine was tested in terms of the rice separation efficiency, stone separation efficiency, tray loss and impurity level after separation. The result showed an average of 81.75%, 7.33%, 18.25% and 27.27% for rice separation efficiency, stone separation efficiency, tray loss and impurity after separation respectively for local rice variety under study. The developed machine has the promise of solving the problem of stone infestation usually encountered in locally produced rice. Keywords: fabrication and performance, rice destoner DOI: 10.7176/JNSR/9-22-07 Publication date: November 30th 201

Quality of life in restorative versus non-restorative resections for rectal cancer:systematic review

BACKGROUND: Low rectal cancers could be treated using restorative (anterior resection, AR) or non-restorative procedures with an end/permanent stoma (Hartmann’s, HE; or abdominoperineal excision, APE). Although the surgical choice is determined by tumour and patient factors, quality of life (QoL) will also influence the patient's future beyond cancer. This systematic review of the literature compared postoperative QoL between the restorative and non-restorative techniques using validated measurement tools. METHODS: The review was registered on PROSPERO (CRD42020131492). Embase and MEDLINE, along with grey literature and trials websites, were searched comprehensively for papers published since 2012. Inclusion criteria were original research in an adult population with rectal cancer that reported QoL using a validated tool, including the European Organization for Research and Treatment of Cancer QLQ-CR30, QLQ-CR29, and QLQ-CR38. Studies were included if they compared AR with APE (or HE), independent of study design. Risk of bias was assessed using the Risk Of Bias In Non-Randomized Studies of Interventions (ROBINS-I) tool. Outcomes of interest were: QoL, pain, gastrointestinal (GI) symptoms (stool frequency, flatulence, diarrhoea and constipation), and body image. RESULTS: Nineteen studies met the inclusion criteria with a total of 6453 patients; all papers were observational and just four included preoperative evaluations. There was no identifiable difference in global QoL and pain between the two surgical techniques. Reported results regarding GI symptoms and body image documented similar findings. The ROBINS-I tool highlighted a significant risk of bias across the studies. CONCLUSION: Currently, it is not possible to draw a firm conclusion on postoperative QoL, pain, GI symptoms, and body image following restorative or non-restorative surgery. The included studies were generally of poor quality, lacked preoperative evaluations, and showed considerable bias in the data

Short-term and long-term cardiovascular risk, metabolic syndrome and HIV in Tanzania.

OBJECTIVE: To compare short-term and long-term cardiovascular disease (CVD) risk scores and prevalence of metabolic syndrome in HIV-infected adults receiving and not receiving antiretroviral therapy (ART) to HIV-negative controls. METHODS: A cross-sectional study including 151 HIV-infected, ART-naive, 150 HIV-infected on ART and 153 HIV-negative adults. Traditional cardiovascular risk factors were determined by standard investigations. The primary outcome was American College of Cardiology/American Heart Association Atherosclerotic CVD (ASCVD) Risk Estimator lifetime CVD risk score. Secondary outcomes were ASCVD 10-year risk, Framingham risk scores, statin indication and metabolic syndrome. RESULTS: Compared with HIV-negative controls, more HIV-infected adults on ART were classified as high lifetime CVD risk (34.7% vs 17.0%, p<0.001) although 10-year risk scores were similar, a trend which was similar across multiple CVD risk models. In addition, HIV-infected adults on ART had a higher prevalence of metabolic syndrome versus HIV-negative controls (21.3% vs 7.8%, p=0.008), with two common clusters of risk factors. More than one-quarter (28.7%) of HIV-infected Tanzanian adults on ART meet criteria for statin initiation. CONCLUSIONS: HIV-infected ART-treated individuals have high lifetime cardiovascular risk, and this risk seems to develop rapidly in the first 3-4 years of ART as does the development of clusters of metabolic syndrome criteria. These data identify a new subgroup of low short-term/high-lifetime risk HIV-infected individuals on ART who do not currently meet criteria for CVD risk factor modification but require further study

Protocol investigating the clinical outcomes and cost-effectiveness of cognitive–behavioural therapy delivered remotely for unscheduled care users with health anxiety: randomised controlled trial

Background Health anxiety and medically unexplained symptoms cost the National Health Service (NHS) an estimated £3 billion per year in unnecessary costs with little evidence of patient benefit. Effective treatment is rarely taken up due to issues such as stigma or previous negative experiences with mental health services. An approach to overcome this might be to offer remotely delivered psychological therapy, which can be just as effective as face-to-face therapy and may be more accessible and suitable. Aims To investigate the clinical outcomes and cost-effectiveness of remotely delivered cognitive–behavioural therapy (CBT) to people with high health anxiety repeatedly accessing unscheduled care (trial registration: NCT02298036). Method A multicentre randomised controlled trial (RCT) will be undertaken in primary and secondary care providers of unscheduled care across the East Midlands. One hundred and forty-four eligible participants will be equally randomised to receive either remote CBT (6–12 sessions) or treatment as usual (TAU). Two doctoral research studies will investigate the barriers and facilitators to delivering the intervention and the factors contributing to the optimisation of therapeutic outcome. Results This trial will be the first to test the clinical outcomes and costeffectiveness of remotely delivered CBT for the treatment of high health anxiety. Conclusions The findings will enable an understanding as to how this intervention might fit into a wider care pathway to enhance patient experience of care

Using power analysis and spatial prioritization to evaluate the design of a forest bird monitoring programme

Biodiversity monitoring programmes should be designed with sufficient statistical power to detect population change. Here we evaluated the statistical power of monitoring to detect declines in the occupancy of forest birds on Christmas Island, Australia. We fitted zero-inflated binomial models to 3 years of repeat detection data (2011, 2013 and 2015) to estimate single-visit detection probabilities for four species of concern: the Christmas Island imperial pigeon Ducula whartoni, Christmas Island white-eye Zosterops natalis, Christmas Island thrush Turdus poliocephalus erythropleurus and Christmas Island emerald dove Chalcophaps indica natalis. We combined detection probabilities with maps of occupancy to simulate data collected over the next 10 years for alternative monitoring designs and for different declines in occupancy (10–50%). Specifically, we explored how the number of sites (60, 128, 300, 500), the interval between surveys (1–5 years), the number of repeat visits (2–4 visits) and the location of sites influenced power. Power was high (> 80%) for the imperial pigeon, white-eye and thrush for most scenarios, except for when only 60 sites were surveyed or a 10% decline in occupancy was simulated over 10 years. For the emerald dove, which is the rarest of the four species and has a patchy distribution, power was low in almost all scenarios tested. Prioritizing monitoring towards core habitat for this species only slightly improved power to detect declines. Our study demonstrates how data collected during the early stages of monitoring can be analysed in simulation tools to fine-tune future survey design decisions