149 research outputs found
Dopant Evaporation Sources For Molecular-beam Epitaxy
No full textTwo simple dopant evaporation sources are described and characterized for use in a III-V molecular beam epitaxy (MBE) system. The first is for the evaporation of silicon donors and utilizes a strip of silicon from a commercial doped wafer. The advantages are its cleanliness as shown by the significantly lower compensation ratio, speed of response to current changes allowing abrupt doping changes, efficiency and reliability. Following the design considerations of the silicon strip source we constructed a beryllium source. Instabilities in the heating pattern showed that beryllium could not be reliably used until we redesigned the source to allow the beryllium to be held by a tantalum foil. This redesign was successful, with high efficiency and fast response, but secondary ion mass spectrometry (SIMS) results show oxygen incorporation similar to that of conventionally evaporated beryllium. The same SIMS results show abrupt ( less-than-or-equal-to 50 angstrom) doping profiles made by changing the current through the source (i.e. without the use of the shutter)
Review of “Hydraulic Engineering of Dams” by Willi H. Hager, Anton J. Schleiss, Robert M. Boes, and Michael Pfister
No full textNo abstract. This is a book review.The presentation of the authors' names and (or) special characters in the title of the pdf file of the accepted manuscript may differ slightly from what is displayed on the item page. The information in the pdf file of the accepted manuscript reflects the original submission by the author
Location of the hydrophobic pocket in the binding site of fentanyl analogs in the m-opioid receptor
No full textFentanyl is a highly potent and clinically widely used narcotic analgesic. The synthesis of its analogs remains a challenge in an attempt to develop highly selective m-opioid receptor agonists with specific pharmacological properties. In this paper, the use of flexible molecular docking of several specific fentanyl analogs to the m-opioid receptor model, in order to test the hypothesis that the hydrophobic pocket accommodates alkyl groups at position 3 of the fentanyl skeleton, is described. The stereoisomers of the following compounds were studied: cis- and trans-3-methylfentanyl, 3,3-dimethylfentanyl, cis- and trans-3-ethylfentanyl, cis- and trans-3-propylfentanyl, cis-3-isopropylfentanyl and cis-3-benzylfentanyl. The optimal position and orientation of these fentanyl analogs in the binding pocket of the m-receptor, explaining their enantiospecific potency, were determined. It was found that the 3-alkyl group of cis-3R,4S and trans-3S,4S stereoisomers of all the active compounds occupies the hydrophobic pocket between TM5, TM6 and TM7, made up of the amino acids Trp318 (TM7), Ile322 (TM7), Ile301 (TM6) and Phe237 (TM5). However, the fact that this hydrophobic pocket can also accommodate the bulky 3-alkyl substituents of the two inactive compounds: cis-3-isopropylfentanyl, and cis-3-benzylfentanyl, indicates that this hydrophobic pocket in the employed receptor model is probably too large
Local Nature of Artificial Homojunction Band Discontinuities
No full textThe feasibility of creating homojunction band discontinuities by dipole intralayers was recently demonstrated with photoemission studies. We explored the nature of this intriguing mechanism by studying the effects of several complex intralayers, specifically stacked sequences of dipole intralayers. Quite unexpectedly, we found that the magnitude of the corresponding discontinuities is comparable to those created by individual dipole intralayers. We discuss this result in light of the recently observed [L. Sorba, G. Bratina, G. Ceccone, A. Antonini, J. F. Walker, M. Micovic, and A. Franciosi, Phys. Rev. B 43, 2450 (1991)], similarly unpredicted saturation at low thickness of intralayer-induced heterojunction band discontinuities modifications.LSELPRXCnr,ist struttura mat,i-00044 frascati,italy. ecole polytech fed lausanne,inst phys appl,ch-1015 lausanne,switzerland. Marsi, m, univ wisconsin,dept phys,madison,wi 53706.ISI Document Delivery No.: JJ22
Development of Empirical Equations and Tables For the Design of Bridge Cantilever Deck Slabs Under CHBDC Truck Loading
No full textThis study recommends new simplified equations for the transverse moment and shear force at the base of the cantilever overhang due to applied vertical truck loading. This was made possible through a parametric study that utilized finite-element modelling on bridge deck cantilevers with variable lengths and slab thicknesses. Different end stiffening arrangements were considered that are encountered in practice, and included but were not limited to the PL-1, PL-2 and PL-3 New Jersey-type barriers walls, a PL-2 parapet, and a curb supporting intermittent steel posts carrying a guardrail. The barrier length changed from 3 to 12 m and the cantilever length ranged from 1.0 to 3.75 m. Further to the empirical expressions that had been developed, the study is supported by tables that were developed to readily design the cantilever slab, based on vertical loads due to vertical truck loading, as well as horizontal railing loads against the barrier wall
TRGOVINSKE USLUGE
No full textAmong the numerous service activities, trade services are particularly important.
They belong to the group of the most important intangible and commercial services,
which are provided in the function of exchange of goods. Due to their importance,
trade services are subject to regulation in a number of legal acts that have been
adopted so far. It can be noticed that Serbian legislation has gone through several
different stages in this regard. The author provides an overview of these stages
through the chronological analysis of different legislative wording of trade services
and at the same time identifies the room for improvement of the current legislative
framework with a particular suggestions de lege ferenda. In order to undoubtedly
determine legal scope of trade services, one should keep in mind common rules
setting the framework for their performance. Accordingly, these rules are classified
and presented in the paper, including the consequences that arise in case of violation
of these rules.Publishe
Fuentes Rodríguez, Catalina, ed. Estrategias argumentativas y discurso político. Madrid: Arco/Libros, 2016. 351 pp. (ISBN: 978-84-7635-949-5) [RECENSIÓN]
No full textAssessing the effectiveness of Communication Media in Health
No full textThis is a strategy paper for developing effective communication strategies in health in the state of Rajasthan, India. Rajasthan is one among the poor performing states in Health and Family Welfare. The author first presents the current stains of communication strategies, which have been developed by the called Information Education and Communication (IEC) Bureau. Further, few indicators and methods are suggested to develop a strategy for effective communication on Health. The author would like to probe few research questions for developing strategies. What are the various reasons for the poor performance of the IEC Bureau ' Is it due to poor co-ordination among various levels of health functionaries? Or due to less involvement of health personnel in IEC activities? Is it because the Media selected are not appropriate? etc. The present paper is an attempt to answer a few of them.IEC, Health Communication, effectiveness, output outcome
Application of the British Columbia MetPortal for Estimation of Probable Maximum Precipitation and Probable Maximum Flood for a Coastal Watershed
No full textEstimation of the Probable Maximum Precipitation (PMP) and Probable Maximum Flood (PMF) are regulatory requirements in many jurisdictions that are used in the design of dams and assessment of existing infrastructure. The recently available British Columbia MetPortal provides regionally consistent PMP and precipitation frequency estimates across the province of British Columbia (BC). This paper proposes an approach to process and apply this data for the estimation of the PMF for watersheds across British Columbia. Guidelines are presented for selection of transposition points applicable to a watershed, and algorithms are developed for processing the geospatial probable maximum storm and precipitation frequency data. The algorithms developed are generic to multiple software and programming environments, and could also be applied in other regions where spatially and temporally intact PMP estimates are available. A detailed description of data sources and development of PMF scenario inputs is provided, as well as details of important sensitivity analyses. The methodology is applied to estimate the PMF for the Cheakamus Basin north of Squamish British Columbia. The application of the MetPortal PMP and precipitation frequency estimates, when used with a consistent PMF development methodology as proposed in this paper, will help improve the consistency of PMF estimates for watersheds across the province, offering a welcome improvement for dam owners and regulators
Análisis y comparativa de los debates políticos de primer nivel en España (2015 y 2016) y Serbia (2016): nuevos formatos televisivos para nuevos escenarios políticos
No full textLa historia de los debates electorales es un claro reflejo del contexto político de un país ante un momento tan relevante como son unas elecciones generales. España y Serbia son dos países de distinta cultura democrática y actualidad política; no obstante, en los dos estados existe una reciente tradición de los debates políticos que se celebran en las campañas electorales generales, parlamentarias y presidenciales. El principal objetivo de este estudio es realizar un análisis comparativo del formato de estos programas electorales televisados para observar los resultados, las principales similitudes y las diferencias en la realización, los temas tratados, el papel de los moderadores y la distribución espacial y temporal. En España, ante las elecciones generales de 2015 se celebraron tres debates de primer nivel, a dos (PP-PSOE), a tres (PSOE-Podemos-Ciudadanos) y a cuatro (PP-PSOE-Podemos-Ciudadanos), organizados por la Academia de las Ciencias y las Artes de Televisión, El País Digital y el grupo Atresmedia, respectivamente. En junio de 2016, se convocaron elecciones generales, ya que no se logró formar un Gobierno con los resultados anteriores, y en esta ocasión se realizó un solo debate a cuatro (PP-PSOE-Podemos-Ciudadanos). Por otro lado, en las últimas elecciones parlamentarias en Serbia, el 24 de abril de 2016, se han llevado a cabo tres debates, los días 19, 20 y 21 de abril, en los que han participado hasta 10 partidos y movimientos ciudadanos. Todos los debates fueron organizados por la Radio Televisión Serbia y el Centro para las Elecciones Libres y Democracia (CeSID).The history of election debates is a clear reflection of the political context of a country at such an important moment as the general elections. Spain and Serbia are two countries of different democratic culture and political reality; however, in the two states there is a recent tradition of political debates that are organized in general, parliamentary and presidential election campaigns. The main objective of this study is a comparative analysis of the format of these electoral television programs in order to observe the results, the main similarities and differences in the realization, the discussed topics, the role of the moderators and the spatial and temporal distribution. In Spain, before the general elections in 2015, three debates were organized between two candidates (PP-PSOE), among three (PSOE-Podemos-Ciudadanos) and four candidates (PP-PSOE-Podemos-Ciudadanos). The debates were organized by the Academy of Television Sciences and Arts, El País Digital and Atresmedia group, respectively. In June 2016, new general elections were held in Spain because the political parties failed to form a government with previous results. This time only one debate was organized among four candidates (PP-PSOE-Podemos-Ciudadanos). On the other hand, in the last parliamentary elections in Serbia, on April 24, 2016, three debates were organized, on 19, 20 and 21 April, in which participated up to 10 parties and citizens' movements. All debates were organized by Radio Television of Serbia and the Center for Free Elections and Democracy (CeSID)
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