166 research outputs found
Study of the Negative Magneto-Resistance of Single Proton-Implanted Lithium-Doped ZnO Microwires
The magneto-transport properties of single proton-implanted ZnO and of
Li(7\%)-doped ZnO microwires have been studied. The as-grown microwires were
highly insulating and not magnetic. After proton implantation the Li(7\%) doped
ZnO microwires showed a non monotonous behavior of the negative
magneto-resistance (MR) at temperature above 150 K. This is in contrast to the
monotonous NMR observed below 50 K for proton-implanted ZnO. The observed
difference in the transport properties of the wires is related to the amount of
stable Zn vacancies created at the near surface region by the proton
implantation and Li doping. The magnetic field dependence of the resistance
might be explained by the formation of a magnetic/non magnetic heterostructure
in the wire after proton implantation.Comment: 6 pages with 5 figure
La comunicazione politica nei manifesti della campagna elettorale 2008
Il presente lavoro si propone di prendere in esame i criteri comunicativi adottati dai principali partiti
nei manifesti elettorali prodotti in occasione delle elezioni politiche del 2008. Dopo una breve parte
propedeutica sulla comunicazione politica ed un excursus sulla storia del manifesto politico si
procede ad analizzare dettagliatamente i manifesti elettorali dei principali partiti: Il Popolo della
LibertĂ , Alleanza Nazionale, Lega Nord, La Destra, Partito Democratico, Italia dei Valori,
Unione di Centro, Partito Socialista, La Sinistra, l’Arcobaleno. L’analisi si basa sui manifesti che è
stato possibile rintracciare sui siti internet dei partiti e nella Rete in generale. I principali campi di
indagine sono: il tipo di immagini scelte dai partiti a suffragio delle loro proposte politiche, la
grafica, i colori e il lessico adottato per attirare l’attenzione dell’elettore e convincerlo ad orientare il
suo voto in una determinata direzion
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Optimal measurement of surface shortwave irradiance using current instrumentation -- the ARM experience
Shortwave (solar) measurements of surface irradiance for clear sky conditions disagree with a number of different models. Betts used the European Center for Medium-range Forecasts (ECMWF) shortwave model to calculate surface irradiance that were 5-10 percent higher than measurements. Wild used a different formulation of the ECMWF shortwave model, but found that the model overpredicted clear-sky shortwave and average of 3 percent. Ding and Wang used data from the Atmospheric Radiation Measurement (ARM) program and found that the GENESIS GCM shortwave model, likewise, overpredicted clear-sky irradiance by about 4 percent. To help resolve the measurement dilemma, reference instruments were deployed in April 1996 at the Southern Great Plains ARM site central facility very near the shortwave measurements. The rest of the paper describes the experiment undertaken to ascertain total horizontal shortwave irradiance at the surface, including a separation of the direct normal and diffuse horizontal components. Results and a discussion of same concludes the paper
Intercomparison of spectroradiometers and Sun photometers for the determination of the aerosol optical depth during the VELETA-2002 field campaign
[ 1] In July 2002 the VELETA-2002 field campaign was held in Sierra Nevada ( Granada) in the south of Spain. The main objectives of this field campaign were the study of the influence of elevation and atmospheric aerosols on measured UV radiation. In the first stage of the field campaign, a common calibration and intercomparison between Licor-1800 spectroradiometers and Cimel-318 Sun photometers was performed in order to assess the quality of the measurements from the whole campaign. The intercomparison of the Licor spectroradiometers showed, for both direct and global irradiances, that when the comparisons were restricted to the visible part of the spectrum the deviations were within the instruments' nominal accuracies which allows us to rely on these instruments for measuring physical properties of aerosols at the different measurement stations. A simultaneous calibration on AOD data was performed for the Cimel-318 Sun photometers. When a common calibration and methodology was applied, the deviation was lowered to much less than 0.01 for AOD. At the same time an intercomparison has been made between the AOD values given by the spectroradiometers and the Sun photometers, with deviations obtained from 0.01 to 0.03 for the AOD in the visible range, depending on the channel. In the UVA range, the AOD uncertainty was estimated to be around 0.02 and 0.05 for Cimel and Licor respectively. In general the experimental differences were in agreement with this uncertainty estimation. In the UVB range the AOD measurements should not be used due to maximum instrumental uncertainties
Representation of target-bound drugs by computed conformers: implications for conformational libraries
BACKGROUND: The increasing number of known protein structures provides valuable information about pharmaceutical targets. Drug binding sites are identifiable and suitable lead compounds can be proposed. The flexibility of ligands is a critical point for the selection of potential drugs. Since computed 3D structures of millions of compounds are available, the knowledge of their binding conformations would be a great benefit for the development of efficient screening methods. RESULTS: Integration of two public databases allowed superposition of conformers for 193 approved drugs with 5507 crystallised target-bound counterparts. The generation of 9600 drug conformers using an atomic force field was carried out to obtain an optimal coverage of the conformational space. Bioactive conformations are best described by a conformational ensemble: half of all drugs exhibit multiple active states, distributed over the entire range of the reachable energy and conformational space. A number of up to 100 conformers per drug enabled us to reproduce the bound states within a similarity threshold of 1.0 Ă… in 70% of all cases. This fraction rises to about 90% for smaller or average sized drugs. CONCLUSION: Single drugs adopt multiple bioactive conformations if they interact with different target proteins. Due to the structural diversity of binding sites they adopt conformations that are distributed over a broad conformational space and wide energy range. Since the majority of drugs is well represented by a predefined low number of conformers (up to 100) this procedure is a valuable method to compare compounds by three-dimensional features or for fast similarity searches starting with pharmacophores. The underlying 9600 generated drug conformers are downloadable from the Super Drug Web site [1]. All superpositions are visualised at the same source. Additional conformers (110,000) of 2400 classified WHO-drugs are also available
DIMA - Annotation Guidelines for German Intonation
KĂĽgler F, Smolibocki B, Arnold D, et al. DIMA - Annotation Guidelines for German Intonation. In: Proceedings of the 18th International Congress of Phonetic Sciences. Glasgow, Scotland; 2015: 317.This paper presents newly developed guidelines for
prosodic annotation of German as a consensus
system agreed upon by German intonologists. The
DIMA system is rooted in the framework of
autosegmental-metrical phonology. One important
goal of the consensus is to make exchanging data
between groups easier since German intonation is
currently annotated according to different models.
To this end, we aim to provide guidelines that are
easy to learn. The guidelines were evaluated running
an inter-annotator reliability study on three different
speech styles (read speech, monologue and
dialogue). The overall high Îş between 0.76 and 0.89
(depending on the speech style) shows that the
DIMA conventions can be applied successfully
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