Applying the extended molecule approach to correlated electron transport: important insight from model calculations

Theoretical approaches of electronic transport in correlated molecules usually consider an extended molecule, which includes, in addition to the molecule itself, parts of electrodes. In the case where electron correlations remain confined within the molecule, and the extended molecule is sufficiently large, the current can be expressed by means of Laudauer-type formulae. Electron correlations are embodied into the retarded Green function of a sufficiently large but isolated extended molecule, which represents the key quantity that can be accurately determined by means of ab initio quantum chemical calculations. To exemplify these ideas, we present and analyze numerical results obtained within full CI calculations for an extended molecule described by the interacting resonant level model. Based on them, we argue that for organic electrodes the transport properties can be reliably computed, because the extended molecule can be chosen sufficiently small to be tackled within accurate ab initio methods. For metallic electrodes, larger extended molecules have to be considered in general, but a (semi-)quantitative description of the transport should still be possible particularly in the typical cases where electron transport proceeds by off-resonant tunneling. Our numerical results also demonstrate that, contrary to the usual claim, the ratio between the characteristic Coulomb strength and the level width due to molecule-electrode coupling is not the only quantity needed to assess whether electron correlation effects are strong or weak

Pengaruh Media Simpan dan Lama Penyimpanan terhadap Viabilitas Benih dan Pertumbuhan Semai Mahoni (Swietenia Mahagoni (L.) Jacq)

Tujuan penelitian ini adalah untuk mengetahui pengaruh media simpan, lama penyimpanan, dan interaksi antara media simpan dan lama penyimpanan terhadap viabilitas dan pertumbuhan semai mahoni. Metode yang digunakan dalam penelitian ini adalah metode eksperimental menggunakan rancangan acak lengkap faktorial, dimana faktor pertama adalah media simpan, dan faktor kedua adalah lama penyimpanan. Parameter yang diamati dalam penelitian ini adalah persen kadar air, laju perkecambahan, persentase tumbuh, tinggi tanaman, jumlah daun, diameter batang, dan berat berangkasan kering tanaman. Analisis data dilakukan dengan menggunakan analisis sidik ragam pada taraf nyata 5%. Hasil penelitian menunjukkan bahwa media simpan tidak berpengaruh nyata terhadap viabilitas dan pertumbuhan semai mahoni, sementara lama penyimpanan yaitu laju pertumbuhan, jumlah daun, dan berat berangkasan kering berpengaruh nyata terhadap viabilitas dan pertumbuhan semai mahoni. Uji lanjut terhadap parameter yang menunjukkan beda nyata yaitu menggunakan uji Duncan pada taraf nyata 5 %. Pertumbuhan terbaik terjadi pada lama penyimpanan 2 pekan (B1). Sedangkan kombinasi perlakuan antara media simpan dan lama penyimpanan menunjukkan tidak adanya interaksi

L’ADAPTATION POSITIVE DES FAMILLES LATINOS AVEC UN ENFANT AYANT UNE DÉFICIENCE INTELLECTUELLE: UNE PREMIÈRE VUE DE LA THÉORIE DE L’ADAPTATION POSITIVE

Historically, research on disability and family dynamics drew from Psychology and Medicine. Consequently, eugenics models, grief theory, and other largely decontextualized frameworks of stress and coping were used to explain families of children with disabilities. This is a report of an initial test of a set of ideas the Singer research team has combined in order to explore the cognitive and problem-solving approaches of families of children with disabilities. Our purpose is to propose a contextualized theory for explaining how cultural diversity has an impact on positive adaptation to a child’s disability. This theory addresses the following: 1) attachment; 2) internal and external cultural resistance to stigmas about disability; and 3) perceived informal (family/friends) and formal (professionals) sources of support for positive views about disability and parenting. Sampling Latino families demonstrated how cultural contexts demonstrate a different flavour from majority culture interpretations of these cognitive terms of our proposed theory. Transcripts of the interviews were coded using grounded theory analysis, specifically, the constant comparative method. We discuss the goodness of fit for themes emerging from the coding process with the proposed theory terms. Results confirm attachment, social supports, and cultural resistance as terms for future development of this proposed theory. Keywords: Disability and parenting, positive adaptation, Latinos and disability, culture and disabilityÀ travers l’histoire, la recherche sur les handicapés et les relations intrafamiliales utilisait comme sources la psychologie et la médicine. Par conséquent, les modèles de l’eugénisme, les théories sur le deuil, et d’autres cadres analytiques sur le stress et les stratégies d’adaptation, plutôt décontextualisés, étaient utilisés afin d’expliquer aux autres comment fonctionnaient les familles avec un enfant handicapé. Ceci est un reportage sur un test initial d’un ensemble d’idées qu’a combiné l’équipe de recherche Singer afin d’aborder les approches cognitives et méthodes actives des familles des enfants handicapés. Nous proposons une théorie contextualisée afin d’expliquer comment la diversité culturelle aurait un effet sur l’adaptation positive de la famille face à l’handicap de leur enfant. Cette théorie aborde les idées suivantes : 1) l’attachement; 2) les résistances culturelles internes et externes aux stigmates sur l’handicap; et 3) les sources d’information sur l’handicap et le parentage liées à l’adaptation positive perçues comme informelles (famille/amis) et formelles (les professionnels). En utilisant un échantillon de familles Latinos, nous démontrons comment les contextes culturels démontrent des interprétations différentes des termes cognitifs de notre théorie, et non l’interprétation de la culture majoritaire. Les transcriptions des interviews étaient codées selon la théorie ancrée, plus spécifiquement la méthode de la comparaison constante. Nous discutons la concordance des thèmes venus via le processus d’encodage avec les termes clés de la nouvelle théorie proposée. Les résultats de cette recherche confirment que l’attachement, le soutien social, et la résistance culturelle seront des termes clés dans le développement de cette théorie proposée. Mots clés : Handicap et parentage, Adaptation positive, Latinos et handicap, culture et handica

Thermal properties of the orthorhombic CaSnO3 perovskite under pressure from ab initio quasi-harmonic calculations

Made available in DSpace on 2018-12-11T16:41:31Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-02-01Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Structural, elastic and thermodynamic properties of the orthorhombic CaSnO3 perovskite are theoretically investigated at the ab initio level as a function of temperature and pressure. Harmonic and quasi-harmonic lattice dynamical calculations are performed with the Crystal program, by explicitly accounting for thermal expansion effects and by exploring the effect of several DFT functionals. The anisotropic, directional elastic response of the system is characterized up to 20 GPa of pressure. The thermal lattice expansion and elastic bulk modulus are described at simultaneous temperatures up to 2000 K and pressures up to 20 GPa. The Gibbs free energy of formation of CaSnO3 from CaO and SnO2 as a function of temperature is also addressed by means of fully converged phonon dispersion calculations on the three systems.Laboratório de Combustíveis e Materiais INCTMN-UFPB Universidade Federal da ParaíbaGrupo de Modelagem e Simulação Molecular INCTMN-UNESP São Paulo State UniversityDipartimento di Chimica Università di Torino and NIS Nanostructured Interfaces and Surfaces Centre of Excellence, Via Giuria 5Grupo de Modelagem e Simulação Molecular INCTMN-UNESP São Paulo State UniversityFAPESP: 2013/07296-2FAPESP: 2013/19289-

Review Article Multiphoton Ionization and Fragmentation of Hydrogen Chloride: A Diatomic Still Good for a Surprise

The competition between multiphoton ionization and fragmentation in the diatomic molecule hydrogen chloride is reviewed. Emphasis is laid on recent experimental results employing chemical imaging methods in order to obtain kinetic energy distributions and angular distributions of photoproducts. The energy range considered is 15 to 20 eV, equivalent to the absorption of three or four photons in the ultraviolet wavelength range. The role of Rydberg states as resonantly excited intermediate states in the ionization/fragmentation processes is assessed. Mixing among 1 Σ + states gives rise to peculiarly shaped double minimum potential energy curves which allow for the production of hydrogen and chlorine atomic and ionic fragments via several competing pathways, in addition to the production of molecular HCl + ions. States with different electronic properties show a qualitatively different behaviour from Σ + states. Accidental resonances between states of differing orbital angular momentum or multiplicity serve to override these differences and cause subtle as well as significant deviations from the unperturbed behaviour

STRATEGIC GEOGRAPHIC POSITIONING OF SEA LEVEL GAUGES TO AID IN EARLY DETECTION OF TSUNAMIS IN THE INTRA-AMERICAS SEA

The potential impact of past Caribbean tsunamis generated by earthquakes and/or massive submarine slides/slumps, as well as the tsunamigenic potential and population distribution within the Intra-Americas Sea (IAS) is examined to help define the optimal location for coastal sea level gauges intended to serve as elements of a regional tsunami warning system. The goal of this study is to identify the minimum number of sea level gauge locations to aid in tsunami detection and provide the most warning time to the largest number of people. We identified 12 initial, prioritized locations for coastal sea level gauge installation. Our study area approximately encompasses 7oN, 59oW to 36oN, 98oW. The results of this systematic approach to assess priority locations for coastal sea level gauges will assist in developing a tsunami warning system (TWS) for the IAS by the National Oceanic and Atmospheric Administration (NOAA) and the Regional Sub-Commission for the Caribbean and Adjacent Regions (IOCARIBE-GOOS)