Strain and structure driven complex magnetic ordering of a CoO overlayer on Ir(100)

We have investigated the magnetic ordering in the ultrathin c(10$\times$2) CoO(111) film supported on Ir(100) on the basis of ab-initio calculations. We find a close relationship between the local structural properties of the oxide film and the induced magnetic order, leading to alternating ferromagnetically and anti-ferromagnetically ordered segments. While the local magnetic order is directly related to the geometric position of the Co atoms, the mismatch between the CoO film and the Ir substrate leads to a complex long-range order of the oxide.Comment: 5 pages, 4 figure

Thoughts of self-harm in early and late pregnancy in urban South Africa: Investigating prevalence, predictors and screening options

Background. Thoughts of self-harm (TSH) are an important marker of mental health risk, and risk for attempted and completed suicide. While there is increasing attention being paid to mental health problems in pregnancy in South Africa (SA), TSH have received less attention despite some cross-sectional studies suggesting that prevalence may be high (12 - 39%). There is a dearth of longitudinal research to inform prevention and treatment.Objectives. To examine the rates of TSH across pregnancy in a longitudinal SA cohort and to investigate factors associated with the onset and persistence of TSH, as well as the relationship between TSH, depression and/or anxiety.Methods. Women were enrolled in a prospective pregnancy cohort (S1000) in Soweto, SA between 2014 and 2016, and assessed using validated screening measures (Edinburgh Postnatal Depression Scale (EPDS) and State Trait Anxiety Index short form) in early and later pregnancy. Data were available for 649 women. TSH were determined using EPDS item 10. Logistic regression and bifactor models were used to determine factors associated with TSH across pregnancy.Results. Of the 649 women, 18% reported TSH at some stage during their pregnancy. Prevalence of TSH was slightly higher in early pregnancy (12.5%) than later in pregnancy (11.6%). TSH were associated with a history of mental illness (adjusted odds ratio (aOR) 4.17; 95% confidence interval (CI) 1.3 - 13.7; p=0.020), concurrent depression (aOR 4.8; 95%CI 2.7 - 8.6; p<0.001); marital stress (aOR 1.74; 95% CI 1.0 - 3.0; p=0.040); and practical support (aOR 0.43; 95% CI 0.2 - 1.0; p=0.040) using a multivariate logistic regression. Bifactor analysis examining depression and anxiety scales showed that TSH contributed the highest variance to a shared depression and anxiety factor in early pregnancy. Logistic regressions showed that early depression was a strong predictor of later reports of TSH.Conclusions. The present study shows that the risk of TSH during pregnancy is relatively common, and starts early during pregnancy. Screening approaches could be simplified to encourage healthcare practitioners working in busy and over-burdened public healthcare settings to engage in identifying at-risk women. Efforts in improving early identification of mental health risk in pregnancy should be matched with strengthening of current treatment and referral options. Since practical support and a good marital relationship reduce the risk of TSH, these may be important avenues of focus for designing interventions

Physical routes for the synthesis of kesterite

This paper provides an overview of the physical vapor technologies used to synthesize Cu2ZnSn(S,Se)4 thin films as absorber layers for photovoltaic applications. Through the years, CZT(S,Se) thin films have been fabricated using sequential stacking or co-sputtering of precursors as well as using sequential or co-evaporation of elemental sources, leading to high-efficient solar cells. In addition, pulsed laser deposition of composite targets and monograin growth by the molten salt method were developed as alternative methods for kesterite layers deposition. This review presents the growing increase of the kesterite-based solar cell efficiencies achieved over the recent years. A historical description of the main issues limiting this efficiency and of the experimental pathways designed to prevent or limit these issues is provided and discussed as well. Afinal section is dedicated to the description of promising process steps aiming at further improvements of solar cell efficiency, such as alkali doping and bandgap grading1. R Caballero and M León acknowledge financial support via the Spanish Ministry of Science, Innovation and Universities project (WINCOST, ENE2016-80788-C5-2-R) and thank H2020 EU Programme under the project INFINITE-CELL (H2020-MSCA-RISE-2017-777968). 2. S Canulescu and J Schou acknowledge the support from Innovation Fund Denmark. 3. D-H Kim acknowledges financial support via the DGIST R&D Program of the Ministry of Science and ICT, KOREA (18-BD-05). 4.C. Malerba acknowledges the support from the Italian Ministry of Economic development in the framework of the Operating Agreement with ENEA for the Research on the Electric System. 5.A Redinger acknowledges financial support via the FNR Attract program, Project : SUNSPOT, Nr.11244141. 6. E Saucedo thanks H2020 EU Programme under the projects STARCELL (H2020-NMBP-03-2016-720907) and INFINITE-CELL (H2020-MSCA-RISE-2017-777968), the Spanish Ministry of Science, Innovation and Universities for the IGNITE project (ENE2017-87671-C3-1-R), and the European Regional Development Funds (ERDF, FEDER Programa Competitivitat de Catalunya 2007–2013). IREC belong to the SEMS (Solar Energy Materials and Systems) Consolidated Research Group of the ‘Generalitat de Catalunya’ (Ref. 2017 SGR 862). 7. Taltech acknowledges financial support via the Estonian Ministry of Education and Research funding project IUT19-28 and the European Union Regional Development Fund, Project TK141. 8. B Vermang has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 Research and Innovation Programme (Grant Agreement No 715027

Observations of Comet 2P/Encke During the Fall 2013 Apparition

We will present preliminary results from our observational campaign of Comet 2P/Encke during its 2013 perihelion passage. At optical wavelengths Encke is an extremely dust poor comet that has in past perihelion passages emitted a gas jet in the form a sunward fan. We expect to characterize both the morphology and lightcurve of the comet. The low optical dust means that even near perihelion the nuclear signature can be obtained in lightcurve data taken with narrowband continuum filters which cut out the gas emission. The campaign will consist of both narrowband and broadband imaging as well as infrared spectroscopy. Imaging will be obtained from 8 nights on the KPNO 2.1m between Sept. 7 and 14 UT. Additionally, the Murillo Family Observatory, a 0.5m telescope on the CSUSB campus which is equipped with both broadband filters and a narrowband Hale-Bopp set of filters will be used to observe the comet every clear night the moon allows between late August and early October to obtain extensive lightcurve data. These data will overlap both the Kitt Peak observations and the infrared spectroscopy which will be obtained with the SpeX instrument at the IRTF on four nights between September 26 UT and October 2 UT

First trimester antenatal depression and anxiety:prevalence and associated factors in an urban population in Soweto, South Africa

Depression and anxiety in the antenatal period are of public health concern given potential adverse effects for both mother and infant. Both are under-researched in the first trimester of pregnancy, especially in Africa. We examine the prevalence of first trimester antenatal depression and anxiety in a cohort of South African women and investigate associated risk factors. Data were collected from 946 women (2014–2016) in the Soweto First 1000 Days Cohort, a prospective pregnancy cohort in Soweto, South Africa. Antenatal depression was assessed using the Edinburgh Postnatal Depression Scale with a score of ⩾13 indicating probable depression. Anxiety was assessed using the short form of the State-Trait Anxiety Index with a score ⩾12 indicating probable anxiety. Prevalence of antenatal depression was 27% [95% confidence interval (CI) 24.2–29.8] and anxiety 15.2% (95% CI 12.9–17.5). Factors associated with antenatal depression and anxiety were predominantly relationship- and family-centred. Women who perceived that their partner made life harder for them had three-fold increased odds for depression [(odds ratio (OR) 3.33 [2.28–4.85] P&lt;0.001], whereas those with family stressors had almost double the odds for depression (OR 1.78 [1.22–2.59] P=0.003) and anxiety (OR 1.75 [1.44–2.69] P=0.0011). Antenatal depression and anxiety are common in the first trimester of pregnancy, and partner and family relationship stressors are central. Longitudinal analysis is needed to determine if this is a phase of adjustment to pregnancy or onset of persistent symptomology. Early intervention may have secondary preventative effects and should involve the partner and family.</jats:p

Theory for Metal Hydrides with Switchable Optical Properties

Recently it has been discovered that lanthanum, yttrium, and other metal hydride films show dramatic changes in the optical properties at the metal-insulator transition. Such changes on a high energy scale suggest the electronic structure is best described by a local model based on negatively charged hydrogen (H$^-$) ions. We develop a many-body theory for the strong correlation in a H$^-$ ion lattice. The metal hydride is described by a large $U$-limit of an Anderson lattice model. We use lanthanum hydride as a prototype of these compounds, and find LaH$_3$ is an insulator with a substantial gap consistent with experiments. It may be viewed either as a Kondo insulator or a band insulator due to strong electron correlation. A H vacancy state in LaH$_3$ is found to be highly localized due to the strong bonding between the electron orbitals of hydrogen and metal atoms. Unlike the impurity states in the usual semiconductors, there is only weak internal optical transitions within the vacancy. The metal-insulator transition takes place in a band of these vacancy states.Comment: 18 pages, 16 figures and 6 tables. Submitted to PR

Emerging nanomagnetism in 4d transition metal nanowires

Monatomic nanowires of the nonmagnetic transition metals Ru, Rh, and Pd have been studied theoretically, using first-principles computational techniques, in order to investigate the possible onset of magnetism in these nanosystems. Our fully relativistic spin-polarized all-electron density functional calculations reveal the onset of Hund's rule magnetism in nanowires of all three metals, with mean-field moments of 1.1, 0.3, and 0.7 bohr magnetons, respectively, at the equilibrium bond length. An analysis of the band structures indicates that the nanocontact superparamagnetic state suggested by our calculations should affect the ballistic conductance between tips made of Ru, Rh or Pd, leading to possible temperature and magnetic field dependent conductance.Comment: 5 figures, 17 pages New content with respect to old arxiv versio

Secondary crystalline phases identification in Cu2ZnSnSe4 thin films: contributions from Raman scattering and photoluminescence

In this work, we present the Raman peak positions of the quaternary pure selenide compound Cu2ZnSnSe4 (CZTSe) and related secondary phases that were grown and studied under the same conditions. A vast discussion about the position of the X-ray diffraction (XRD) reflections of these compounds is presented. It is known that by using XRD only, CZTSe can be identified but nothing can be said about the presence of some secondary phases. Thin films of CZTSe, Cu2SnSe3, ZnSe, SnSe, SnSe2, MoSe2 and a-Se were grown, which allowed their investigation by Raman spectroscopy (RS). Here we present all the Raman spectra of these phases and discuss the similarities with the spectra of CZTSe. The effective analysis depth for the common back-scattering geometry commonly used in RS measurements, as well as the laser penetration depth for photoluminescence (PL) were estimated for different wavelength values. The observed asymmetric PL band on a CZTSe film is compatible with the presence of CZTSe single-phase and is discussed in the scope of the fluctuating potentials’ model. The estimated bandgap energy is close to the values obtained from absorption measurements. In general, the phase identification of CZTSe benefits from the contributions of RS and PL along with the XRD discussion.info:eu-repo/semantics/publishedVersio

Condition Evaluation of In-service Chemically Stabilized Subgrades in a High Sulfate Environment

State Job No. 135443This project included measurements of strength properties, soil properties, and chemical content of natural and chemically stabilized subgrade soil from five projects across Ohio, three from sites that have historically had high sulfate content, and two that have not. The objective was to compare the properties of the soils from the sites and determine if there were crystals of ettringite or thaumasite in the soil, which would indicate potential for heaving. Site testing included PSPA, FWD, LWD, DCP, SPT, an informal distress survey, and collection of soil specimens for laboratory analysis, which included standard soils tests (Grain size, Atterberg limits, organic content, moisture content, pH, and sulfate content as determined in Ohio Supplement 1122), and chemistry analysis comprising neutralization potential, and X-ray diffraction. In the control sections, measured sulfate levels were low in the natural subgrade and higher in the stabilized subgrade but still below the criterion of concern at 3000 ppm. In the high sulfate sections, natural subgrade had still higher sulfate content, but still usually below 3000 ppm, while the stabilized subgrade generally had content above 3000 ppm, but no more than 6500 ppm to 9500 ppm depending on the site. However, the X-ray diffraction found no measurable quantity of ettringite or thaumasite crystals, indicating that conditions for formation were not met at any of the sites. The pH of stabilized soil at all locations was just above 10, which was one condition that was met. None of the pavements showed any signs of damage due to sulfate heaving. The continued practice of global stabilization of subgrade soil is recommended. The undercut section on LAK-2 showed less variability than the other section, and this approach may be considered where cost effective