5,251 research outputs found
A case study on regularity in cellular network deployment
This paper aims to validate the -Ginibre point process as a model for
the distribution of base station locations in a cellular network. The
-Ginibre is a repulsive point process in which repulsion is controlled
by the parameter. When tends to zero, the point process
converges in law towards a Poisson point process. If equals to one it
becomes a Ginibre point process. Simulations on real data collected in Paris
(France) show that base station locations can be fitted with a -Ginibre
point process. Moreover we prove that their superposition tends to a Poisson
point process as it can be seen from real data. Qualitative interpretations on
deployment strategies are derived from the model fitting of the raw data
Effect of pine bark and compost on the biological denitrification process of non-hazardous landfill leachate: Focus on the microbiology
In an attempt to optimize the cost-efficiency of landfill leachate treatment by biological denitrification process, our study focused on finding low-cost alternatives to traditional expensive chemicals such as composted garden refuse and pine bark, which are both available in large amount in South African landfill sites. The overall objective was to assess the behaviour of the bacterial community in relation to each substrate while treating high strength landfill leachates. Denitrification processes in fixed bed reactors were simulated at laboratory scale using anaerobic batch tests with immature compost and pine bark. High strength leachate was simulated using a solution of water and nitrate at a concentration of 500 mg l−1. Results suggest that pine bark released large amounts of phenolic compounds and hydroxylated benzene rings, which both can delay the acclimatization time and inhibit the biological denitrification (only 30% efficiency). Furthermore, presence of potential pathogens like Enterobacter and Pantoea agglomerans prevents the applicability of the pine bark in full-scale operations. On the other hand, lightly composted garden refuse (CGR) offered an adequate substrate for the formation of a biofilm necessary to complete the denitrification process (total nitrate removal observed within 7 days). CGR further contributed to a rapid establishment of an active consortium of denitrifiers including Acinetobacter, Rhizobium, Thermomonas, Rheinheimera, Phaeospirillum and Flavobacterium. Clearly the original composition, nature, carbon to nitrogen ratio (C/N) and degree of maturity and stability of the substrates play a key role in the denitrification process, impacting directly on the development of the bacterial population and, therefore, on the long-term removal efficiency
Molecular model for the self-assembly of the cyclic lipodepsipeptide pseudodesmin A
Self-assembly of peptides into supramolecular structures represents an active field of research with potential applications ranging from material science to medicine. Their study typically involves the application of a large toolbox of spectroscopic and imaging techniques. However, quite often, the structural aspects remain underexposed. Besides, molecular modeling of the self-assembly process is usually difficult to handle, since a vast conformational space has to be sampled. Here, we have used an approach that combines short molecular dynamics simulations for peptide dimerization and NMR restraints to build a model of the supramolecular structure from the dimeric units. Experimental NMR data notably provide crucial information about the conformation of the monomeric units, the supramolecular assembly dimensions, and the orientation of the individual peptides within the assembly. This in silico/in vitro mixed approach enables us to define accurate atomistic models of supramolecular structures of the bacterial cyclic lipodepsipeptide pseudodesmin A
Reconnaître la différence : le défi de l’ethnopsychiatrie
La reconnaissance de la différence de l’Autre est le fondement de la légitimité de l’ethnopsychiatrie qui est donc nécessairement multiple, changeante, et elle-même porteuse de nuances et de différences. C’est à partir de leur pratique clinique au Service d’aide psychologique spécialisée aux immigrants et réfugiés (SAPSIR), que les auteurs proposent un autre regard sur cette discipline prenant en compte, bien sûr, la dimension culturelle et psychique de la personne ; ils s’appuient aussi sur des universaux existentiels et humanistes tels le besoin de sens, de continuité de soi et de cohérence ainsi que sur les diverses dimensions de l’identité. Le dispositif clinique proposé, respectueux des principes de l’ethnopsychiatrie, s’articule autour de trois axes : travail sur les liens, travail sur les différentes dimensions identitaires, travail sur la cohérence et le sens des situations vécues. Cette démarche permet d’accompagner et de faciliter les élaborations essentielles impliquées dans le travail psychique des réfugiés et des personnes ayant été exposés à des situations extrêmes telle la torture.Recognizing difference of the Other is the basis of legitimacy of ethnopsychiatry that is necessarily multiple, changing, and itself bearing subtleties and variations. It is from their practice at the Service d’aide psychologique spécialisée aux immigrants et réfugiés (SAPSIR), that the authors propose another perspective of this discipline taking into account of course, the cultural and psychological dimension of the individual; they also consider existential and humanistic universals such as the need of giving meaning, of continuity of the self and coherence as well as the various dimensions of identity. Their clinical approach, respectful of the principles of ethnopsychiatry, is structured around three axis : work on links, work on different dimensions of identity, work on coherence and meaning of situations experienced. This approach allows to accompany and facilitate essential elaborations involved in the psychological work of refugees as well as individuals exposed to extreme situations such as torture.El reconocimiento de la diferencia del Otro es la base de la legitimidad de la etnopsiquiatrÃa, la cual es necesariamente múltiple, cambiante y en sà portadora de sutilezas y diferencias. Es a partir de su práctica clÃnica en el Servicio de ayuda psicológica especializada para los inmigrantes y refugiados (SAPSIR) que los autores proponen otra visión acerca de esta disciplina, tomando en cuenta, por supuesto, la dimensión cultural y psÃquica de la persona; se apoyan también en los universales esenciales y humanistas, tales como la necesidad de sentido, de continuidad de sà mismo y de coherencia, asà como en el sentido de las situaciones vividas. El dispositivo clÃnico propuesto, el cual respeta los principios de la etnopsiquiatrÃa, se articula alrededor de tres ejes: el trabajo en los enlaces, el trabajo en las diferentes dimensiones de la identidad y el trabajo en la coherencia y el sentido de las situaciones vividas. Este paso permite acompañar y facilitar las elaboraciones esenciales implicadas en el trabajo psÃquico de los refugiados y de las personas que han sido expuestas a situaciones extremas, tales como la tortura.Reconhecer a diferença do Outro é o fundamento da legitimidade da etnopsiquiatria, que é necessariamente múltipla, variante, e portadora de nuances e de diferenças. É a partir de sua prática clÃnica no Serviço de AuxÃlio Psicológico Especializado aos Imigrantes e Refugiados (SAPSIR) que os autores propõem um outro olhar sobre esta disciplina, levando em consideração, obviamente, a dimensão cultural e psÃquica da pessoa; eles se apóiam também sobre os universos existenciais e humanistas como a necessidade de sentido, de continuidade de si mesmo e de coerência, assim como sobre as diversas dimensões da identidade. O dispositivo clÃnico proposto, de acordo com os princÃpios da etnopsiquiatria, articula-se em três eixos: trabalho sobre as relações, trabalho sobre as diferentes dimensões identitárias, trabalho sobre a coerência e o sentido das situações vivenciadas. Esta abordagem permite acompanhar e facilitar as elaborações essenciais implicadas no trabalho psÃquico dos refugiados e das pessoas que foram expostas a situações extremas, como a tortura
El 'se' télico y la delimitación del complemento verbal en el español de Argentina y de Venezuela
Telicity is an aspectual semantic notion characterized by the presence of a linguistically marked inherent endpoint of the situation. In Spanish, there is a particle known as telic se that appears only in sentences that carry the telic aspectual value. According to De Miguel (1999) the presence of indefinite plural determiners in the verbal complement leads to an atelic reading and, due to that, the telic se cannot appear in sentences with such verbal construction; on the other hand, Gomes and Martins (in press), based on Spanish spoken in Spain data, state that this verbal construction leads to a telic reading and the telic se appears in sentences with such structure. In view of this, the objective of this work is to verify if the telic se can be combined with verbs whose complements are introduced by indefinite plural determiners in the Spanish spoken in Argentina and Venezuela. For that, a commented grammaticality judgment test was applied to 15 speakers of each one of these varieties. The results indicated that this combination is possible in Argentine and Venezuelan Spanish. We argue that the telic aspectual value of a sentence does not depend on a precise quantification for delimiting the complement.La telicidad es una noción aspectual semántica que se caracteriza por la presencia de un punto final inherente de la situación marcado lingüÃsticamente. En español, hay un clÃtico que se conoce por se télico que se puede usar solamente en sentencias que transmiten el valor aspectual télico. Según De Miguel (1999) la presencia de determinantes plurales indefinidos en el complemento verbal conduce a una lectura atélica y, por eso, no se puede usar el se télico en sentencias que contengan dicha construcción, al paso que, para Gomes y Martins (en prensa), basados en datos del español de España, esa construcción verbal conduce a una lectura télica y, por lo tanto, el uso del se télico es posible. AsÃ, se objetiva en este trabajo verificar si se puede combinar el se télico con verbos cuyos complementos sean introducidos por determinantes plurales indefinidos en el español de Argentina y de Venezuela. Para este fin, se aplicó un test de juicio de gramaticalidad comentado a 15 hablantes nativos de esas variedades. Los resultados indican que dicha combinación es posible en ambas. Se discutió que el valor aspectual télico de una sentencia no depende de una cuantificación precisa para la delimitación del complemento
Estrutura do componente arbóreo de um remanescente de floresta estacional semidecÃdua ribeirinha em Cruz Alta, Rio Grande do Sul.
Objetivou-se analisar a estrutura fitossociológica do componente arbóreo em uma floresta estacional semidecÃdua sujeita a inundações frequentes, identificando-se as espécies que determinam a estrutura do remanescente. Em 16 unidades amostrais de 10x10 m, foram avaliados todos os indivÃduos arbóreos com PAP ≥ 15 cm, sendo calculados os parâmetros de densidade, frequencia e dominância absolutos para as espécies amostradas. Foram amostrados 224 indivÃduos de 21 espécies, 20 gêneros e 17 famÃlias botânicas. As espécies com maior densidade e frequencia absoluta foram Cupania vernalis Cambess., Sebastiania commersoniana (Baill.) L.B Smith & R.J Downs, Luehea divaricata Mart., Ocotea pulchella Mart. e Sebastiania brasiliensis Spreng. A espécie Parapiptadenia rigida (Benth.) Brenan apresentou baixa densidade e frequência, porém, com indivÃduos de grande porte, conferindo-lhe elevada dominância absoluta. Quanto à s estimativas de diversidade e equabilidade, o Ãndice de Shannon (H) foi de 2,16 nats.ind-1 e equabilidade de Pielou (J) foi de 0,71. A maioria dos indivÃduos amostrados apresentou menos de 10 m de altura e até 15 cm de diâmetro. O remanescente apresentou baixa riqueza de espécies, situação caracterÃstica de áreas sujeitas a inundações frequentes. Por outro lado, a presença de espécies caracterÃsticas de área inundáveis, como Pouteria salicifolia (Spreng.) Radlk. indica a necessidade de conservação destes remanescentes, sobretudo pelo papel ecológico que as áreas ribeirinhas desempenham na região
Zinc Sorption to Three Gram-Negative Bacteria: Combined Titration, Modeling, and EXAFS Study
The acid-base and Zn sorption properties of three bacteria, Cupriavidus metallidurans CH34, Pseudomonas putida ATCC12633, and Escherichia coli K12DH5R, were investigated through an original combination of extended X-ray absorption fine structure (EXAFS) spectroscopy and equilibrium titration studies. Acid-base titration curves of the three strains were fitted with a model accounting for three conceptual reactive sites: an acidic (carboxyl and/ or phosphodiester), a neutral (phosphomonoester), and a basic (amine and/or hydroxyl) group. Calculated proton and Zn equilibrium constants and site densities compare with literature data. The nature of Zn binding sites was studied by EXAFS spectroscopy. Phosphoester, carboxyl, and unexpectedly sulfhydryl ligands were identified. Their proportions depended on Zn loading and bacterial strain and were consistent with the titration results. These findings were compared to the structure and site density of the major cell wall components. It appeared that the cumulated theoretical site density of these structures (<2 Zn nm-2) was much lower than the total site density of the investigated strains (16-56 Zn nm-2). These results suggest a dominant role of extracellular polymeric substances in Zn retention processes, although Zn binding to inner cell components cannot be excluded
X-shooter, NACO, and AMBER observations of the LBV Pistol Star \footnote{Based on ESO runs 85.D-0182A, 085.D-0625AC}
We present multi-instruments and multi-wavelengths observations of the famous
LBV star Pistol Star. These observations are part of a larger program about
early O stars at different metallicities. The Pistol star has been claimed as
the most massive star known, with 250 solar masses. We present the preliminary
results based on X-Shooter spectra, as well as the observations performed with
the VLTI-AMBER and the VLT-NACO adaptive optics. The X-shooter spectrograph
allows to obtain simultaneously a spectrum from the UV to the K-band with a
resolving power of 15000. The preliminary results obtained indicate that
Pistol Star has similar properties of Eta Car, including shells of matter, but
also the binarity. Other objects of the program, here briefly presented, were
selected for their particular nature: early O stars with mass discrepancies
between stellar evolution models and observations, discrepancies with the wind
momentum luminosity relation.Comment: Poster at the 39th LIAC, submitted version of the proceeding
Long term trends in aerosol optical characteristics in the Po Valley, Italy
Aerosol properties have been monitored by ground-based in situ and remote sensing measurements at the station for atmospheric research located in Ispra, on the edge of the Po Valley, for almost one decade. In situ measurements are performed according to Global Atmosphere Watch recommendations, and quality is assured through the participation in regular inter-laboratory comparisons. Sunphotometer data are produced by the Aerosol Robotic Network (AERONET). Data show significant decreasing trends over the 2004–2010 period for a number of variables, including particulate matter (PM) mass concentration, aerosol scattering, backscattering and absorption coefficients, and aerosol optical thickness (AOT). In situ measurement data show no significant trends in the aerosol backscatter ratio, but they do show a significant decreasing trend of about −0.7±0.3%yr−1 in the aerosol single scattering albedo
(SSA) in the visible light range. Similar trends are observed in the SSA retrieved from sun-photometer measurements.
Correlations appear between in situ PM mass concentration and aerosol scattering coefficient, on the one hand, and elemental
carbon (EC) concentration and aerosol absorption coefficient, on the other hand. However, no increase in the EC /PM ratio was observed, which could have explained the decrease in SSA. The application of a simple approximation to calculate the direct radiative forcing by aerosols suggests a significant diminution in their cooling effect, mainly due to the decrease in AOT. Applying the methodology we present
to those sites, where the necessary suite of measurements is available, would provide important information to inform future policies for air-quality enhancement and fast climate change mitigation.JRC.H.2-Air and Climat
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