982 research outputs found

    Lattice dynamics study of cubic Tb2O3

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    "This is the peer reviewed version of the following article: Ibáñez, Jordi, Oriol Blázquez, Sergi Hernández, Blas Garrido, Plácida Rodríguez-Hernández, Alfonso Muñoz, Matias Velázquez, Philippe Veber, and Francisco Javier Manjón. 2018. Lattice Dynamics Study of Cubic Tb 2 O 3. Journal of Raman Spectroscopy 49 (12). Wiley: 2021 27. doi:10.1002/jrs.5488, which has been published in final form at https://doi.org/10.1002/jrs.5488. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving."[EN] We report a joint experimental and theoretical study of the lattice dynamics of cubic Tb2O3. Up to 16 optical Raman-active modes have been observed with polarized and unpolarized Raman scattering measurements on a high-quality Tb2O3 single crystal. The measured wavenumbers have been compared with those of other rare-earth (RE) and related sesquioxides with cubic (C-type or bixbyite) structure. First-principles calculations have allowed us to assign the symmetry of the experimentally observed Raman-active modes. Additional lattice-dynamical calculations on the related cubic RE sesquioxides Dy2O3, Gd2O3, Eu2O3, and Sm2O3 indicate that the phonon wavenumbers of the Raman-active modes in these compounds are monotonically reduced with increasing the lattice parameter along the Dy2O3-Tb2O3-Gd2O3-Eu2O3-Sm2O3 series, thus prompting for a revision of the experimental Raman spectra of some of these compounds (mainly Eu2O3 but also Gd2O3).This study was supported by the Spanish Ministerio de Economía y Competitividad under Projects MAT2015-71070-REDC, MAT2015-71035-R, MAT2016-75586-C4-2-P/3-P, and FIS2017-2017-83295-P.Ibanez, J.; Blazquez, O.; Hernandez, S.; Garrido, B.; Rodríguez-Hernández, P.; Munoz, A.; Velazquez, M.... (2018). Lattice dynamics study of cubic Tb2O3. Journal of Raman Spectroscopy. 49(12):2021-2027. https://doi.org/10.1002/jrs.5488S202120274912Pan, T.-M., Chen, F.-H., & Jung, J.-S. (2010). Structural and electrical characteristics of high-k Tb2O3 and Tb2TiO5 charge trapping layers for nonvolatile memory applications. Journal of Applied Physics, 108(7), 074501. doi:10.1063/1.3490179Kao, C. H., Liu, K. C., Lee, M. H., Cheng, S. N., Huang, C. H., & Lin, W. K. (2012). High dielectric constant terbium oxide (Tb2O3) dielectric deposited on strained-Si:C. Thin Solid Films, 520(8), 3402-3405. doi:10.1016/j.tsf.2011.10.173Gray, N. W., Prestgard, M. C., & Tiwari, A. (2014). Tb2O3 thin films: An alternative candidate for high-k dielectric applications. Applied Physics Letters, 105(22), 222903. doi:10.1063/1.4903072Geppert, I., Eizenberg, M., Bojarczuk, N. A., Edge, L. F., Copel, M., & Guha, S. (2010). Determination of band offsets, chemical bonding, and microstructure of the (TbxSc1−x)2O3/Si system. Journal of Applied Physics, 108(2), 024105. doi:10.1063/1.3427554Belaya, S. V., Bakovets, V. V., Boronin, A. I., Koshcheev, S. V., Lobzareva, M. N., Korolkov, I. V., & Stabnikov, P. A. (2014). Terbium oxide films grown by chemical vapor deposition from terbium(III) dipivaloylmethanate. Inorganic Materials, 50(4), 379-386. doi:10.1134/s0020168514040037Bakovets, V. V., Belaya, S. V., Lobzareva, M. N., & Maksimovskii, E. A. (2014). Kinetics of terbium oxide film growth from Tb(dpm)3 vapor. Inorganic Materials, 50(6), 576-581. doi:10.1134/s0020168514060016Veber, P., Velázquez, M., Gadret, G., Rytz, D., Peltz, M., & Decourt, R. (2015). Flux growth at 1230 °C of cubic Tb2O3single crystals and characterization of their optical and magnetic properties. CrystEngComm, 17(3), 492-497. doi:10.1039/c4ce02006eAbrashev, M. V., Todorov, N. D., & Geshev, J. (2014). Raman spectra of R2O3 (R—rare earth) sesquioxides with C-type bixbyite crystal structure: A comparative study. Journal of Applied Physics, 116(10), 103508. doi:10.1063/1.4894775Urban, M. W., & Cornilsen, B. C. (1987). Bonding anomalies in the rare earth sesquioxides. Journal of Physics and Chemistry of Solids, 48(5), 475-479. doi:10.1016/0022-3697(87)90108-9Hohenberg, P., & Kohn, W. (1964). Inhomogeneous Electron Gas. Physical Review, 136(3B), B864-B871. doi:10.1103/physrev.136.b864Kresse, G., & Furthmüller, J. (1996). Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane-wave basis set. Computational Materials Science, 6(1), 15-50. doi:10.1016/0927-0256(96)00008-0Blöchl, P. E. (1994). Projector augmented-wave method. Physical Review B, 50(24), 17953-17979. doi:10.1103/physrevb.50.17953Kresse, G., & Joubert, D. (1999). From ultrasoft pseudopotentials to the projector augmented-wave method. Physical Review B, 59(3), 1758-1775. doi:10.1103/physrevb.59.1758Perdew, J. P., Burke, K., & Ernzerhof, M. (1996). Generalized Gradient Approximation Made Simple. Physical Review Letters, 77(18), 3865-3868. doi:10.1103/physrevlett.77.3865Perdew, J. P., Ruzsinszky, A., Csonka, G. I., Vydrov, O. A., Scuseria, G. E., Constantin, L. A., … Burke, K. (2008). Restoring the Density-Gradient Expansion for Exchange in Solids and Surfaces. Physical Review Letters, 100(13). doi:10.1103/physrevlett.100.136406Monkhorst, H. J., & Pack, J. D. (1976). Special points for Brillouin-zone integrations. Physical Review B, 13(12), 5188-5192. doi:10.1103/physrevb.13.5188Garcia-Domene, B., Ortiz, H. M., Gomis, O., Sans, J. A., Manjón, F. J., Muñoz, A., … Tyagi, A. K. (2012). High-pressure lattice dynamical study of bulk and nanocrystalline In2O3. Journal of Applied Physics, 112(12), 123511. doi:10.1063/1.4769747Gomis, O., Santamaría-Pérez, D., Ruiz-Fuertes, J., Sans, J. A., Vilaplana, R., Ortiz, H. M., … Mollar, M. (2014). High-pressure structural and elastic properties of Tl2O3. Journal of Applied Physics, 116(13), 133521. doi:10.1063/1.4897241K.Parlinski Phonon code seehttp://www.computingformaterials.com/.Todorov, N. D., Abrashev, M. V., Marinova, V., Kadiyski, M., Dimowa, L., & Faulques, E. (2013). Raman spectroscopy and lattice dynamical calculations of Sc2O3single crystals. Physical Review B, 87(10). doi:10.1103/physrevb.87.104301White, W. B., & Keramidas, V. G. (1972). Vibrational spectra of oxides with the C-type rare earth oxide structure. Spectrochimica Acta Part A: Molecular Spectroscopy, 28(3), 501-509. doi:10.1016/0584-8539(72)80237-xKranert, C., Schmidt-Grund, R., & Grundmann, M. (2014). Raman active phonon modes of cubic In2O3. physica status solidi (RRL) - Rapid Research Letters, 8(6), 554-559. doi:10.1002/pssr.201409004Ubaldini, A., & Carnasciali, M. M. (2008). Raman characterisation of powder of cubic RE2O3 (RE=Nd, Gd, Dy, Tm, and Lu), Sc2O3 and Y2O3. Journal of Alloys and Compounds, 454(1-2), 374-378. doi:10.1016/j.jallcom.2006.12.067Mochizuki, S., Fujishiro, F., & Ishiwata, K. (2005). Photo-induced valence-number changes and defects in Eu2O3fine particle films. Journal of Physics: Conference Series, 21, 189-194. doi:10.1088/1742-6596/21/1/03

    Aspects of Split Supersymmetry

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    We explore some fundamental differences in the phenomenology, cosmology and model building of Split Supersymmetry compared with traditional low-scale supersymmetry. We show how the mass spectrum of Split Supersymmetry naturally emerges from theories where the dominant source of supersymmetry breaking preserves an RR symmetry, characterize the class of theories where the unavoidable RR-breaking by gravity can be neglected, and point out a new possibility, where supersymmetry breaking is directly communicated at tree level to the visible sector via renormalizable interactions. Next, we discuss possible low-energy signals for Split Supersymmetry. The absence of new light scalars removes all the phenomenological difficulties of low-energy supersymmetry, associated with one-loop flavor and CP violating effects. However, the electric dipole moments of leptons and quarks do arise at two loops, and are automatically at the level of present limits with no need for small phases, making them accessible to several ongoing new-generation experiments. We also study proton decay in the context of Split Supersymmetry, and point out scenarios where the dimension-six induced decays may be observable. Finally, we show that the novel spectrum of Split Supersymmetry opens up new possibilities for the generation of dark matter, as the decays of ultraheavy gravitinos in the early universe typically increase the abundance of the lightest neutralino above its usual freeze-out value. This allows for lighter gauginos and Higgsinos, more accessible both to the LHC and to dark-matter detection experiments.Comment: 50 pages, references added, typos correcte

    LHC String Phenomenology

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    We argue that it is possible to address the deeper LHC Inverse Problem, to gain insight into the underlying theory from LHC signatures of new physics. We propose a technique which may allow us to distinguish among, and favor or disfavor, various classes of underlying theoretical constructions using (assumed) new physics signals at the LHC. We think that this can be done with limited data (5−10fb−1)(5-10 fb^{-1}), and improved with more data. This is because of two reasons -- a) it is possible in many cases to reliably go from (semi)realistic microscopic string construction to the space of experimental observables, say, LHC signatures. b) The patterns of signatures at the LHC are sensitive to the structure of the underlying theoretical constructions. We illustrate our approach by analyzing two promising classes of string compactifications along with six other string-motivated constructions. Even though these constructions are not complete, they illustrate the point we want to emphasize. We think that using this technique effectively over time can eventually help us to meaningfully connect experimental data to microscopic theory.Comment: 50 Pages, 13 Figures, 3 Tables, v2: minor changes, references adde

    A personalized intervention to prevent depression in primary care: cost-effectiveness study nested into a clustered randomized trial

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    Background: Depression is viewed as a major and increasing public health issue, as it causes high distress in the people experiencing it and considerable financial costs to society. Efforts are being made to reduce this burden by preventing depression. A critical component of this strategy is the ability to assess the individual level and profile of risk for the development of major depression. This paper presents the cost-effectiveness of a personalized intervention based on the risk of developing depression carried out in primary care, compared with usual care. Methods: Cost-effectiveness analyses are nested within a multicentre, clustered, randomized controlled trial of a personalized intervention to prevent depression. The study was carried out in 70 primary care centres from seven cities in Spain. Two general practitioners (GPs) were randomly sampled from those prepared to participate in each centre (i.e. 140 GPs), and 3326 participants consented and were eligible to participate. The intervention included the GP communicating to the patient his/her individual risk for depression and personal risk factors and the construction by both GPs and patients of a psychosocial programme tailored to prevent depression. In addition, GPs carried out measures to activate and empower the patients, who also received a leaflet about preventing depression. GPs were trained in a 10- to 15-h workshop. Costs were measured from a societal and National Health care perspective. Qualityadjustedlife years were assessed using the EuroQOL five dimensions questionnaire. The time horizon was 18 months. Results: With a willingness-to-pay threshold of (sic)10, 000 ((sic)8568) the probability of cost-effectiveness oscillated from 83% (societal perspective) to 89% (health perspective). If the threshold was increased to (sic)30, 000 ((sic)25, 704), the probability of being considered cost-effective was 94% (societal perspective) and 96%, respectively (health perspective). The sensitivity analysis confirmed these results. Conclusions: Compared with usual care, an intervention based on personal predictors of risk of depression implemented by GPs is a cost-effective strategy to prevent depression. This type of personalized intervention in primary care should be further developed and evaluated

    Striatal interneurons in dissociated cell culture

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    In addition to the well-characterized direct and indirect projection neurons there are four major interneuron types in the striatum. Three contain GABA and either parvalbumin, calretinin or NOS/NPY/somatostatin. The fourth is cholinergic. It might be assumed that dissociated cell cultures of striatum (typically from embryonic day E18.5 in rat and E14.5 for mouse) contain each of these neuronal types. However, in dissociated rat striatal (caudate/putamen, CPu) cultures arguably the most important interneuron, the giant aspiny cholinergic neuron, is not present. When dissociated striatal neurons from E14.5 Sprague–Dawley rats were mixed with those from E18.5 rats, combined cultures from these two gestational periods yielded surviving cholinergic interneurons and representative populations of the other interneuron types at 5 weeks in vitro. Neurons from E12.5 CD-1 mice were combined with CPu neurons from E14.5 mice and the characteristics of striatal interneurons after 5 weeks in vitro were determined. All four major classes of interneurons were identified in these cultures as well as rare tyrosine hydroxylase positive interneurons. However, E14.5 mouse CPu cultures contained relatively few cholinergic interneurons rather than the nearly total absence seen in the rat. A later dissection day (E16.5) was required to obtain mouse CPu cultures totally lacking the cholinergic interneuron. We show that these cultures generated from two gestational age cells have much more nearly normal proportions of interneurons than the more common organotypic cultures of striatum. Interneurons are generated from both ages of embryos except for the cholinergic interneurons that originate from the medial ganglionic eminence of younger embryos. Study of these cultures should more accurately reflect neuronal processing as it occurs in the striatum in vivo. Furthermore, these results reveal a procedure for parallel culture of striatum and cholinergic depleted striatum that can be used to examine the function of the cholinergic interneuron in striatal networks

    Design and rationale of a multicentre, randomised, double-blind, placebo-controlled clinical trial to evaluate the effect of vitamin D on ventricular remodelling in patients with anterior myocardial infarction: the VITamin D in Acute Myocardial Infarction (VITDAMI) trial

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    Introduction:Decreased plasma vitamin D (VD) levels are linked to cardiovascular damage. However, clinical trials have not demonstrated a benefit of VD supplements on left ventricular (LV) remodelling. Anterior ST-elevation acute myocardial infarction (STEMI) is the best human model to study the effect of treatments on LV remodelling. We present a proof-of-concept study that aims to investigate whether VD improves LV remodelling in patients with anterior STEMI. Methods and analysis:The VITamin D in Acute Myocardial Infarction (VITDAMI) trial is a multicentre, randomised, double-blind, placebo-controlled trial. 144 patients with anterior STEMI will be assigned to receive calcifediol 0.266 mg capsules (Hidroferol SGC)/15 days or placebo on a 2:1 basis during 12 months. Primary objective:to evaluate the effect of calcifediol on LV remodelling defined as an increase in LV end-diastolic volume >= 10\% (MRI). Secondary objectives:change in LV end-diastolic and end-systolic volumes, ejection fraction, LV mass, diastolic function, sphericity index and size of fibrotic area; endothelial function; plasma levels of aminoterminal fragment of B-type natriuretic peptide, galectin-3 and monocyte chemoattractant protein-1; levels of calcidiol (VD metabolite) and other components of mineral metabolism (fibroblast growth factor-23 (FGF-23), the soluble form of its receptor klotho, parathormone and phosphate). Differences in the effect of VD will be investigated according to the plasma levels of FGF-23 and klotho. Treatment safety and tolerability will be assessed. This is the first study to evaluate the effect of VD on cardiac remodelling in patients with STEMI. Ethics and dissemination: This trial has been approved by the corresponding Institutional Review Board (IRB) and National Competent Authority (Agencia Espanola de Medicamentos y Productos Sanitarios (AEMPS)). It will be conducted in accordance with good clinical practice (International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use-Good Clinical Practice (ICH-GCP)) requirements, ethical principles of the Declaration of Helsinki and national laws. The results will be submitted to indexed medical journals and national and international meetings.The VITDAMI trial is an investigator initiated study, sponsored by the Instituto de Investigacion Sanitaria Fundacion Jimenez Diaz (IIS-FJD). Funding has been obtained from Fondo de Investigaciones Sanitarias (PI14/01567; http://www.isciii.es/) and Spanish Society of Cardiology (http://secardiologia.es/). In addition, the study medication has been provided freely by the pharmaceutical Company FAES FARMA S.A. (Leioa, Vizcaya, Spain; http://faesfarma.com/). This company was the only funder who collaborated in study design (IG-H).S

    Description of the vitis vinifera L. Phenotypic variability in eno-carpological traits by a Euro-Asiatic collaborative network among ampelographic collections

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    The grapevine intra-specific variability captured an increasing interest during the last decades, as demonstrated by the number of recently funded European projects focused on the grapevine biodiversity preservation. However, nowadays, crop plants are mainly characterized by genotyping methods. The present work summarizes the phenotype data collected among 20 ampelographic collections spread over 15 countries, covering most of the viticultural areas in the Euro-Asiatic region: from Portugal to Armenia and from Cyprus to Luxembourg. Together with agro-climatic characterization of the experimental site, over two years about 2,400 accessions were described. A common experimental protocol mainly focused on the carpological and oe-nological traits was followed, obtaining a general overview of the distribution of the considered phenotypic traits in the cultivated Vitis vinifera species. The most replicated cultivars were selected and, for the subset of these reference cultivars, their behavior in the different environmental conditions over sites and years was described by ANOVA methods

    Gene co-expression architecture in peripheral blood in a cohort of remitted first-episode schizophrenia patients

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    A better understanding of schizophrenia subtypes is necessary to stratify the patients according to clinical attributes. To explore the genomic architecture of schizophrenia symptomatology, we analyzed blood co-expression modules and their association with clinical data from patients in remission after a first episode of schizophrenia. In total, 91 participants of the 2EPS project were included. Gene expression was assessed using the Clariom S Human Array. Weighted-gene co-expression network analysis (WGCNA) was applied to identify modules of co-expressed genes and to test its correlation with global functioning, clinical symptomatology, and premorbid adjustment. Among the 25 modules identified, six modules were significantly correlated with clinical data. These modules could be clustered in two groups according to their correlation with clinical data. Hub genes in each group showing overlap with risk genes for schizophrenia were enriched in biological processes related to metabolic processes, regulation of gene expression, cellular localization and protein transport, immune processes, and neurotrophin pathways. Our results indicate that modules with significant associations with clinical data showed overlap with gene sets previously identified in differential gene-expression analysis in brain, indicating that peripheral tissues could reveal pathogenic mechanisms. Hub genes involved in these modules revealed multiple signaling pathways previously related to schizophrenia, which may represent the complex interplay in the pathological mechanisms behind the disease. These genes could represent potential targets for the development of peripheral biomarkers underlying illness traits in clinical remission stages after a first episode of schizophrenia

    Genetic Etiology of Parkinson Disease Associated with Mutations in the SNCA, PARK2, PINK1, PARK7, and LRRK2 Genes: A Mutation Update

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    To date, molecular genetic analyses have identified over 500 distinct DNA variants in five disease genes associated with familial Parkinson disease; α-synuclein (SNCA), parkin (PARK2), PTEN-induced putative kinase 1 (PINK1), DJ-1 (PARK7), and Leucine-rich repeat kinase 2 (LRRK2). These genetic variants include ∼82% simple mutations and ∼18% copy number variations. Some mutation subtypes are likely underestimated because only few studies reported extensive mutation analyses of all five genes, by both exonic sequencing and dosage analyses. Here we present an update of all mutations published to date in the literature, systematically organized in a novel mutation database (http://www.molgen.ua.ac.be/PDmutDB). In addition, we address the biological relevance of putative pathogenic mutations. This review emphasizes the need for comprehensive genetic screening of Parkinson patients followed by an insightful study of the functional relevance of observed genetic variants. Moreover, while capturing existing data from the literature it became apparent that several of the five Parkinson genes were also contributing to the genetic etiology of other Lewy Body Diseases and Parkinson-plus syndromes, indicating that mutation screening is recommendable in these patient groups. Hum Mutat 31:763–780, 2010. © 2010 Wiley-Liss, Inc
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