Xe Irradiation of Graphene on Ir(111): From Trapping to Blistering

Using X-ray photoelectron spectroscopy, thermal desorption spectroscopy, and scanning tunneling microscopy we show that upon keV Xe + irradiation of graphene on Ir(111), Xe atoms are trapped under the graphene. Upon annealing, aggregation of Xe leads to graphene bulges and blisters. The efficient trapping is an unexpected and remarkable phenomenon, given the absence of chemical binding of Xe to Ir and to graphene, the weak interaction of a perfect graphene layer with Ir(111), as well as the substantial damage to graphene due to irradiation. By combining molecular dynamics simulations and density functional theory calculations with our experiments, we uncover the mechanism of trapping. We describe ways to avoid blister formation during graphene growth, and also demonstrate how ion implantation can be used to intentionally create blisters without introducing damage to the graphene layer. Our approach may provide a pathway to synthesize new materials at a substrate - 2D material interface or to enable confined reactions at high pressures and temperatures

Investigation of low latitude scintillations in Brazil within the cigala project

Ionospheric scintillations are fluctuations in the phase and amplitude of the signals from GNSS satellites occurring when they cross regions of electron density irregularities in the ionosphere. Such disturbances can cause serious degradation on GNSS system performance, including integrity, accuracy and availability. The two indices internationally adopted to characterize ionospheric scintillations are: the amplitude scintillation index, S4, which is the standard deviation of the received power normalized by its mean value, and the phase scintillation index, σΦ, which is the standard deviation of the de-trended carrier phase. At low latitudes scintillations occur very frequently and can be intense. This is because the low latitudes show a characteristic feature of the plasma density, known as the equatorial anomaly, EA, for which a plasma density enhancement is produced and seen as crests on either side of the magnetic equator. It is a region in which the electron density is considerably high and inhomogeneous, producing ionospheric irregularities causing scintillations. The upcoming solar maximum, which is expected to reach its peak around May 2013, occurs at a time when our reliance on high-precision GNSS (such as GPS, GLONASS and the forthcoming GALILEO) has reached unprecedented proportions. Understanding and monitoring of scintillations are essential, so that warnings and forecast information can be made available to GNSS end users, either for global system or local augmentation network administrators in order to guarantee the necessary levels of accuracy, integrity and availability of high precision and/or safety-of-life applications. Especially when facing severe geospatial perturbations, receiver-level mitigations are also needed to minimize adverse effects on satellite signals tracking availability and accuracy. In this context, the challenge of the CIGALA (Concept for Ionospheric scintillation mitiGAtion for professional GNSS in Latin America) project, co-funded by the European GNSS Agency (GSA) through the European 7th Framework Program, is to understand the causes of ionospheric disturbances and model their effects in order to develop novel counter-measure techniques to be implemented in professional multi-frequency GNSS receivers. This paper describes the scientific advancements made within the project to understand and characterize ionospheric scintillation in Brazil by means of historical and new datasets

Cross-Sector social partnership success: A process perspective on the role of relational factors

The study employs partial least squares structural equation modelling to examine cross-sector social partnership success in the context of Spanish business (N = 102). Proposing the development of second-order models, the research identifies the role of relational factors that directly and indirectly affect partnership success. The study demonstrates that to increase partnership success, it is essential for socially responsible businesses to share the same values with their non-profit partners, thus contributing to trust and commitment and effectively enhancing relational effects. Employing relational factors for the conceptualisation of partnership success contributes an empirical quantitative process perspective that associates success with value creation processe

Avaliação da produção lacrimal em gambás filhotes por três diferentes métodos

O estabelecimento do parâmetro de produção lacrimal nas diferentes espécies é importante para o entendimento da saúde do olho e é um dos componentes da semiotécnica oftálmica. Particularidades derivadas da anatomofisiologia das espécies não domésticas induzem a busca de metodologias que sejam mais fidedignas aos parâmetros. Objetivou-se com este estudo avaliar e comparar a produção lacrimal de gambás-de-orelha-branca (Didelphis albiventris) e gambás-de-orelha-preta (Didelphis aurita) por três diferentes métodos. Quinze indivíduos de cada espécie, juvenis, hígidos, de ambos os sexos, com 60 a 90 dias de vida, foram contidos fisicamente para realização do teste lacrimal do vermelho de fenol (TLVF), da ponta de papel absorvente estéril e do teste lacrimal de Schirmer modificado (TLSm). O TLVF foi o mais difícil de ser executado devido à maleabilidade do fio, enquanto a TEPA se mostrou mais exequível para ambas as espécies. A mediana ± intervalo semi-interquartil para o TLVF foi de 19,79±2,61mm/15” e 5,22±2,92mm/15”, para a TEPA foram de 16,25±1,82mm/min e 10,93±3,04mm/min, e para o TLSm foram de 0±1,63mm/min e 0±1,63mm/min, para gambás-de-orelha-branca e gambás-de-orelha-preta, respectivamente. Não houve diferença entre o olho direito e esquerdo e nem quanto ao sexo. Obteve-se diferença significativa para um mesmo teste entre as espécies. Não foi encontrada correlação significativa entre os testes para ambas as espécies. A quantificação da porção aquosa da lágrima poderá auxiliar no diagnóstico precoce de doenças oculares nas espécies estudadas.The establishment of parameters for tear production in different species is important for better understanding eye´s health and is one of the components of the ophthalmic semiological technique. Particularities derived from the anatomophysiology of non-domestic species induce the search for more reliable methodologies. The aim was to evaluate and compare tear production of white-eared opossum (Didelphis albiventris) and Brazilian common opossum (Didelphis aurita) by three different methods. Fifteen individuals of each species, juveniles, healthy, of both sexes, with 60 to 90 days of life, were physically restrained. Phenol red thread test (PRTT), endodontic absorbent paper point tear test (EAPPTT) and modified -Schirmer tear test (mSTT) were performed. PRTT was the most difficult to perform because of the wire malleability, while EAPPTT was more feasible for both species. The median ± semi-quartile range for PRTT were 19.79±2.61mm/15 “and 5.22±2.92mm/15”, for EAPPTT were 16.25±1.82mm/min and 10.9±3.04mm/min, and for STTm were 0±1.63mm/min and 0±1.63mm/min for white-eared opossum and Brazilian common opossum respectively. There was no difference between the right and left eye neither sex. A significant difference was obtained for the same test to different species. No significant correlation was found between the tests for both species. The description of tear production parameters for juvenile white-eared opossum and Brazilian common opossum may be used as a tool, which will allow the early diagnosis of ocular diseases

Satisfaction of students with university institution and academic performance

En el presente artículo, se ha investigado la relación existente entre el rendimiento académico y la satisfacción con la institución educativa en alumnos universitarios. Nuestra hipótesis de partida era que se hallaría una correlación positiva entre ambas variables. Para ello, se utilizó una muestra de 101 estudiantes de Licenciatura en Psicología de la Universidad de Granada. El instrumento de evaluación que se ha utilizado es el SEUE (Satisfacción de los Estudiantes Universitarios con su Educación) de Gento y Vivas (2003). Este instrumento incluye una serie de subdimensiones acerca del constructo estudiado que hemos tenido en cuenta en el análisis estadístico. Tras el análisis de los resultados hemos comprobado que no se ha confirmado la hipótesis, ya que no se observa una correlación significativa entre las variables estudiadas. Junto con la discusión de los resultados, incluimos una serie de limitaciones a tener en cuenta para futuras investigaciones.In the present article, we have investigated the relationship between academic performance and satisfaction with the educational institution in university students. Our hypothesis was that we would be found a positive correlation between both variables. For this, we used a sample of 101 students of degree in psychology at the University of Granada. The assessment tool that has been used is the SEUE (Satisfacción de los Estudiantes Universitarios con su Educación) of Gento and Vivas (2003). This instrument includes some subdimensions about studied construct which we have taken into account in the statistical analysis. After the analysis of the results we have verified that not been confirmed the hypothesis, since there isn´t a significant correlation between the variables studied. Along with the discussion of the results, we have included a series of limitations to keep in mind for future research.Proyecto de innovación docente "ReiDoCrea". Departamento de Psicología Social. Universidad de Granada

Tackling ionospheric scintillation threat to GNSS in Latin America

Scintillations are rapid fluctuations in the phase and amplitude of transionospheric radio signals which are caused by small-scale plasma density irregularities in the ionosphere. In the case of the Global Navigation Satellite System (GNSS) receivers, scintillation can cause cycle slips, degrade the positioning accuracy and, when severe enough, can even lead to a complete loss of signal lock. Thus, the required levels of availability, accuracy, integrity and reliability for the GNSS applications may not be met during scintillation occurrence; this poses a major threat to a large number of modern-day GNSS-based applications. The whole of Latin America, Brazil in particular, is located in one of the regions most affected by scintillations. These effects will be exacerbated during solar maxima, the next predicted for 2013. This paper presents initial results from a research work aimed to tackle ionospheric scintillation effects for GNSS users in Latin America. This research is a part of the CIGALA (Concept for Ionospheric Scintillation Mitigation for Professional GNSS in Latin America) project, co-funded by the EC Seventh Framework Program and supervised by the GNSS Supervisory Authority (GSA), which aims to develop and test ionospheric scintillation countermeasures to be implemented in multi-frequency, multi-constellation GNSS receivers

Valores de referência para selecionados testes oftálmicos para a arara canindé (Ara araruna)

Objetivou-se determinar os valores normais para testes oftálmicos diagnósticos selecionados para a Arara Canindé. Trinta e cinco Ara ararauna (70 olhos), de sexo indeterminado, adultas, com peso médio de 1kg e provenientes de cativeiro no Distrito Federal, foram avaliadas. Aferiram-se a produção lacrimal pelo Teste lacrimal de Schirmer (TLS), a avaliação microbiológica da conjuntiva ocular, a pressão intra-ocular (PIO) utilizando a tonometria de rebote e o comprimento horizontal da rima palpebral Neste estudo 84.1% das amostras analisadas foram positivas para crescimento microbiológico. Bactérias, fungos e hifas foram isolados e Staphylococcus spp. (21.9%) e Bacillus spp. (26.8%) foram isolados mais frequentemente. Os valores médios do teste de Lacrimal de Schirmer (TLS) foram de 7.6±4.6 e 6.6±4.4mm/min para olhos direito (OD) e esquerdo (OE), respectivamente (média = 7,11±0,76mm/min). A pressão intraocular média foi de 11.4±2.5 (OD) e 11.6±1.8mmHg (OE) anteriormente à anestesia (média 11,49±0,22 mmHg) e 7.6 ± 2.4 mmHg (OD) e 7.8 ± 1.8 mm Hg (OE) (média 7,71±0,08mm Hg) após a anestesia, verificando-se que a PIO foi significativamente menor quando os animais se encontravam sob anestesia comparativamente ao momento em que não estavam anestesiados. O comprimento horizontal da rima horizontal palpebral foi de 11.7±0.1mm OD e de 11.8±0.1mm OE (média 11,72±0,07mm). Verificou-se correlação positiva do TLS com o comprimento da fissura palpebral para a espécie estudada. Estes valores de referencia serão úteis no diagnóstico de alterações oculares da Arara Canindé.The aim of this study was to establish reference values for selected ophthalmic diagnostic tests in healthy blue-and-yellow macaws. We investigated a total of 35 adult macaws (70 eyes) of undetermined sex and with an average weight of 1 kg, who were living in captivity in the Federal District, Brazil. Tear production using the Schirmer tear test (STT), normal conjunctival flora, intraocular pressure (IOP) using a rebound tonometer and horizontal palpebral fissure length (HPFL) were evaluated. In this study, 84.1% of samples were positive for microbial growth. Bacteria, fungi and yeasts were isolated, and Staphylococcus spp. (21.9%) and Bacillus spp. (26.8%) were the most frequently isolated microorganisms. The mean value for STT was 7.6±4.6mm/min in the right eye (OD) and 6.6±4.4mm/min in the left eye (OS) (median = 7,11±0,76mm/min). Mean IOP was 11.4±2.5mm Hg OD and 11.6±1.8mm Hg OS (median = 11.49±0.22mm Hg), prior to anesthesia, and 7.6±2.4mm Hg OD and 7.8±1.8mm Hg OS (median 7.71±0.08mmHg) after anesthesia. The IOP was significantly lower when the animals were under anesthesia as compared to when they were conscious (p≤0.05). Horizontal palpebral fissure length was 11.7±0.1mm OD and 11.8±0.1mm OS (median = 11.72±0.07mm). The STT showed a positive correlation with palpebral fissure measurement for this species. These selected ophthalmic reference values will be particularly useful in diagnosing pathological changes in the eyes of blue-and-yellow macaws

Band Calculations for Ce Compounds with AuCu3_{3}-type Crystal Structure on the basis of Dynamical Mean Field Theory I. CePd3_{3} and CeRh3_{3}

Band calculations for Ce compounds with the AuCu$_{3}$-type crystal structure were carried out on the basis of dynamical mean field theory (DMFT). The auxiliary impurity problem was solved by a method named NCA$f^{2}$vc (noncrossing approximation including the $f^{2}$ state as a vertex correction). The calculations take into account the crystal-field splitting, the spin-orbit interaction, and the correct exchange process of the $f^{1} \rightarrow f^{0},f^{2}$ virtual excitation. These are necessary features in the quantitative band theory for Ce compounds and in the calculation of their excitation spectra. The results of applying the calculation to CePd$_{3}$ and CeRh$_{3}$ are presented as the first in a series of papers. The experimental results of the photoemission spectrum (PES), the inverse PES, the angle-resolved PES, and the magnetic excitation spectra were reasonably reproduced by the first-principles DMFT band calculation. At low temperatures, the Fermi surface (FS) structure of CePd$_{3}$ is similar to that of the band obtained by the local density approximation. It gradually changes into a form that is similar to the FS of LaPd$_{3}$ as the temperature increases, since the $4f$ band shifts to the high-energy side and the lifetime broadening becomes large.}Comment: 12 pasges, 13 figure