MoS2 eta WS2 monogeruzen egitura elektroniko eta magnetikoaren ab-initio kalkuloak

Bi dimentsiotako materialetan presente diren propietate elektroniko bereziek betidanik piztu izan dute komunitate zientifikoaren interesa. Idealki atomo bakarreko lodierako materialak diren hauek hasiera batean joku teoriko huts zirela uste bazen ere, A.K. Geim eta K.S. Novoselov-ek kontrakoa frogatu zuten lehenengo aldiz grafenoa sintetizatuz[1]. Grafitoa osatzen duen geruzetako bakoitza den grafenoak guztiz anomaloak diren pro- pietate elektronikoak dauzka, Dirac-en motako sei puntuz besterik ez osatutako Fermi gainazala duelarik. Honen ondorioz, eroapen elektroiak masa gabekoak balira bezala higitzen dira mobilitate elektronikoa areagotuz. Propietate berezi hauetaz baliatuko liratekeen aplikazio teknologiko posibleek[2] material honekiko interesa egun arlo zienti- fikotik at ere hedatzea eragin du. Grafenoaren sintesiaren errekonozimendu gisa Geim eta Novoselov-ek 2010ean fisikaren Nobel saria lortu zuten. Hala ere, grafenoa ez da sintetiza daitekeen material bidimentsional bakarra. Grafenoa lortzeko teknika bera erabiliz (banantze mikromekanikoa), Geim eta Novoselov-ek zu- zendutako taldeak M oS2 eta N bSe2 sintetizatzea lortu zuen[3]. Konkretuki, M oS2 mo- nogeruza erdieroalea izanik transistoreak minimizatzeko prozesuan silizioaren ordezkari gisa jarduteko hautagaia da. Hala ere, hau egin ahal izateko bere propietate elektro- nikoak sakonkiago aztertzea komeni da. Gradu amaierako lan honetan material honen egitura elektronikoaren eta magnetikoaren karakterizazio teorikoan aurrerapauso txiki bat egitea izan dugu helburu. Horrez gain, W S2 materiala ere era berean landu da, tungsteno atomoa pisutsuagoa izatean, spin-orbita elkarrekintzaren eragina nabariagoa izatea espero baita. Modu honetan, lan hau hiru atal nagusitan banatzen da. Lehenengoa teoriari dago- kio, DF T (Dentsitatearen Funtzionalaren Teoria) inplementatzeko oinarri teorikoa lan- du delarik. Magnetizazioa aztertzeko ezinbestekoa den espina inplementatzeko modua ere aztertu da, eta baita egin beharreko hurbilketen eta pseudopotentzialen metodoaren azalpen bat eman ere. Bigarren atalean QuantumEspresso kodea erabiliz burututako ab-initio kalkuluen deskripzio eta emaitzak aurkeztu dira, azkenei dagokien interpreta- zioa eginez. Bertan M oS2 -n bolumenetiketik monogeruzara pasatzeak egitura elektroni- koan duen eragina aztertu da, ondoren M oS2 eta W S2 monogeruzen banda egitura eta magnetizazioan analisi sakonagoa eginez. Azkenengo atalean ateratako ondorioak idatzi dira, etorkizunerako lanetarako ateak zabalduz.

Uraren Kudeaketa Komunala eta publiko-pribatua Ostromen Ikuspegitik

Elinor Ostrom nobel saridunaren ekarpenetatik EAEn uraren kudeaketa komunala egiteko baldintzak betetzen ote diren egindako NIE azterketa.

A interpretação filosófica da mecânica quântica de Werner Heisenberg: ontologia matemática e a crise nos fundamentos da lógica clássica

Qual a Filosofia da Natureza que podemos inferir da Física Contemporânea? Para Werner Karl Heisenberg, prêmio Nobel de Física de 1932, a ontologia da Ciência Moderna, estruturada no materialismo, no mecanicismo e no determinismo já não pode servir de fundamento para a nova Física. Esta requer uma nova base ontológica, onde o antirrealismo, seguido de um formalismo puro, aparece como o princípio basilar de uma nova Filosofia Natural. Este trabalho visa investigar o pensamento filosófico, a ontologia antirrealista, formalista, a abordagem da tradição filosófica e da história da ciência de Werner Heisenberg e sua contribuição para a interpretação da mecânica quântica.

Light-induced change of Si-H bond absorption in hydrogenated amorphous silicon

Device-quality a-Si:H films were prepared by glow discharge CVD with pure or H-diluted silane as well as by hot-wire CVD. The hydrogen content was varied from similar to 2 to 15 at. %. The Si-H bond absorption and its light-soaking-induced changes were studied by IR and differential IR absorption spectroscopes. The results indicate that the more stable sample exhibits an increase of the absorption at wave number similar to 2000 cm(-1), and the less stable one exhibits a decrease at similar to 2040 cm(-1) and an increase at similar to 1880 cm(-1).

Light-excited structural instability of a-Si : H.

With the accumulation of experimental data, it has been recognized by many that the light-induced metastable change of a-Si:H, Staebler-Wronski effect (SWE), may be related to a structural instability of the whole a-Si:H network. However, direct evidence of such a structural change is still lacking. In the present paper, the efforts of our laboratory in this direction will be reviewed, including the light-induced changes of Si-H bond absorption, low frequency dielectric response, and an apparent photo-dilation effect.

High quality hydrogenated amorphous silicon films with significantly improved stability

High quality hydrogenated amorphous silicon (a-Si:H) films have been prepared by a simple "uninterrupted growth/annealing" plasma enhanced chemical vapor deposition (PECVD) technique, combined with a subtle boron-compensated doping. These a-Si:H films possess a high photosensitivity over 10(6), and exhibit no degradation in photoconductivity and a low light-induced defect density after prolonged illumination. The central idea is to control the growth conditions adjacent to the critical point of phase transition from amorphous to crystalline state, and yet to locate the Fermi level close to the midgap. Our results show that the improved stability and photosensitivity of a-Si:H films prepared by this method can be mainly attributed to the formation of a more robust network structure and reduction in the precursors density of light-induced metastable defects.

Structural properties of polycrystalline silicon films formed by pulsed rapid thermal processing

A novel pulsed rapid thermal processing (PRTP) method has been used for realizing the solid-phase crystallization of amorphous silicon films prepared by PECVD. The microstructure and surface morphology of the crystallized films are investigated by X-ray diffraction (XRD) and atomic force microscopy (AFM). The results indicate that this PRTP is a suitable post-crystallization technique for fabricating large-area polycrystalline silicon films with good structural qualities such as large grain size, small lattice microstain and smooth surface morphology on low-cost substrate.

Fractionation and compositional studies of rabbit skeletal muscle membranes

The observations of Hooke (1665), Schleiden & Schwann (1839) and Virchow (1855) led to the identification of the cell as the basic structural unit of living material. In the intervening years, it has been firmly established that the chemical processes which underlie the proper functioning, development and reproduction of the organism are cellular activities. The development of the electron microscope has enabled cell structure to be studied in detail. A picture of the cell as an entity with a complex and highly organised internal structure has emerged from the work of Palade, Porter, Fernandez-Moran and many others. Although cells from different tissues and organisms differ in aspects of their structure and consequently in function, they have several features in common. A retentive membrane encloses a number of cell constituents, which include membrane-enclosed subcellular structures known as organelles. The cells of most tissues also contain a reticulum or system of branching tubules. The interplay of the biochemical activities of these structures enables the cell to function. Almost thirty years ago, Claude, Palade, Schneider, Hogeboom, de Duve and others set out to analytically fractionate the subcellular components obtained after the fragmentation of liver cells. This approach has become known as subcellular fractionation, and signalled a major conceptual breakthrough in biochemistry (reviewed by de Duve, 1964, 1967, 1971). The significance of this breakthrough has been underlined by the award of the 1974 Nobel Prize in Medicine to de Duve, Palade and Claude. This thesis is concerned with the application of subcellular fractionation techniques to the separation and characterisation of the membrane systems of the rabbit skeletal muscle cell.

CANCIONES ARGENTINAS (SONGS OFARGENTINA): A RECORDING PROJECT

This Dissertation Project comprises recordings of Argentine art songs. The discs are approximately 40-60 minutes in length and consist of songs from the traditional art-song repertoire for voice and piano. This project is particularly appropriate because of the very limited number of recordings of Argentine songs, which are notable both not only for their high quality but for their accessibility of performance for voice teachers, students, and professional singers alike. Art songs in the Spanish language are a welcome resource, and the poetry included in this project is of an outstanding quality. Some of the poets set to music are Gabriela Mistral (a poet laureate of Chile and the first Latin American woman to win the Nobel Prize for Literature), Pablo Neruda (also a Nobel laureate), Luis Cernuda, and Leon Benar6s. The lyrics of some songs are based on traditional sources, and the melodies and rhythms of all are representative of South American-indigenous and European­ immigrant cultures. The composers represented here will be familiar to some listeners but more than likely unfamiliar to most. Yet Alberto Ginastera (1916-1983) is considered to be the greatest of all Argentine composers. Alberto Williams (1862-1952) is known as the father of the Nationalist School of composition in Argentina, and Carlos Lopez Buchardo (1881-1963) is a most influential composer and pedagogue after whom the national Conservatory of Music in Buenos Aries is named. Two composers who remain relatively unknown outside of South America, Abraham Jurafsky (1906- 1993) and Julio Perceval (1903-1963) are also represented in this project. A complete compact disc is devoted to the works of Carlos Guastavino. Known as the "Argentine Schubert", Guastavino has over 250 songs to his credit. Chiefly a composer for piano and voice, his recent death (October 2000) makes a recording of his works especially appropriate. This project also includes a written component, a supportive dissertation briefly describing the history of the Argentine art song and the lives and influences of the composers and poets represented in the studio recordings. The CD recordings are held in the Michelle Smith Performing Arts Library at the University of Maryland.

Las cifras de pi y el diálogo en el aula

A partir de un artículo publicado en el Faro de Vigo sobre la petisa Wislawa Szymbirska, Premio Nobel de Literatura, en el que se reproduce su poema el número pi se lleva a cabo una experiencia interdisciplinar con el departamento de lengua y literatura, cuya descripción es el objeto de este trabajo.

Art and Social Work: an intervention programme for transforming society’s vision to include people with early-onset dementia and Alzheimer’s

This paper presents a program centred on arts and education as tools in social work for the inclusion of people with earlyonset dementia and Alzheimer’s. The objective of the programme is to eradicate the stigma and myths associated with the disease.The program is part of the Junta de Castilla y León and the European Social Fund’s ARS Project (Arte y Salud Alzheimer; Alzheimer’s Art & Health). The programme presents a series of evaluated artistic and educational activities that can be undertaken by people in the early stages of Alzheimer’s disease and that can also be used by caregivers and family when working with this group of people, with the aim of improving their wellbeing, self-esteem and quality of life.

The European Union and Peacebuilding: The Cross-Border Dimension

The award of the Nobel Peace Prize to the European Union in 2012 was a reminder of the role of European integration in peacebuilding after the Second World War. For the 'Founding Fathers' of the European integration project, cross-border-cooperation was an integral element in building Europe's peace. Yet, in a Western Europe largely at peace for generations, peacebuilding as a relevant objective for European integration may be questioned. Moreover, the contribution of cross-border cooperation to conflict amelioration may be challenged on the grounds of its overwhelming economic focus. However, enlargement into Central Eastern Europe highlights once again the necessity of a peacebuilding objective for the European Union because of the multitude of real and potential conflicts encompassed within its expanded policy orbit. Drawing on evidence from selected 'borderscapes', this study examines 25 years of European Union cross-border cooperation as conflict amelioration and assesses its prospects in a political climate that emphasises borders as security barriers.