Claro Americas is part of América Móvil, a Mexican telecom group serving clients in Argentina, Brazil, Chile, Colombia, Costa Rica, the Dominican Republic, Ecuador, El Salvador, Guatemala, Honduras, Nicaragua, Panama, Paraguay, Peru, Uruguay. The company's name means "bright", "clear" or "of course" in Portuguese and Spanish. Wikipedia.
Barreiro L.A.,Claro |
Barreiro L.A.,Federal University of Itajubá |
Medina R.,Federal University of Itajubá
Nuclear Physics B | Year: 2014
Recently, in  we proposed a revisited S-matrix approach to efficiently find the bosonic terms of the open superstring low energy effective lagrangian (OSLEEL). This approach allows to compute the α'N terms of the OSLEEL using open superstring n-point amplitudes in which n is considerably lower than (N+2) (which is the order of the required amplitude to obtain those α'N terms by means of the conventional S-matrix approach). In this work we use our revisited S-matrix approach to examine the structure of the scattering amplitudes, arriving at a closed form for them. This is a RNS derivation of the formula first found by Mafra, Schlotterer and Stieberger , using the pure spinor formalism. We have succeeded doing this for the 5, 6 and 7-point amplitudes. In order to achieve these results we have done a careful analysis of the kinematical structure of the amplitudes, finding as a by-product a purely kinematical derivation of the BCJ relations (for N=4, 5, 6 and 7). Also, following the spirit of the revisited S-matrix approach, we have found the α' expansions for these amplitudes up to α'6 order in some cases, by only using the well known open superstring 4-point amplitude, cyclic symmetry and tree level unitarity: we have not needed to compute any numerical series or any integral involving polylogarithms, at any moment. © 2014 The Authors.
Barreiroa L.A.,Claro |
Medina R.,Federal University of Itajubá
Journal of High Energy Physics | Year: 2012
The conventional S-matrix approach to the (tree level) open string low energy effective lagrangian assumes that, in order to obtain all its bosonic α' N order terms, it is necessary to know the open string (tree level) (N+2)-point amplitude of massless bosons, at least expanded at that order in α'. In this work we clarify that the previous claim is indeed valid for the bosonic open string, but for the supersymmetric one the situation is much more better than that: there are constraints in the kinematical bosonic terms of the amplitude (probably due to Spacetime Supersymmetry) such that a much lower open superstring n-point amplitude is needed to find all the α' N order terms. In this 'revisited' S-matrix approach we have checked that, at least up to α' 4 order, using these kinematical constraints and only the known open superstring 4-point amplitude, it is possible to determine all the bosonic terms of the low energy effective lagrangian. The sort of results that we obtain seem to agree completely with the ones achieved by the method of BPS configurations, proposed about ten years ago. By means of the KLT relations, our results can be mapped to the NS-NS sector of the low energy effective lagrangian of the type II string theories implying that there one can also find kinematical constraints in the N-point amplitudes and that important informations can be inferred, at least up to α' 4 order, by only using the (tree level) 4-point amplitude. © SISSA 2012.
News Article | November 28, 2016
Ericsson (NASDAQ: ERIC) has been selected by Claro Colombia for an OSS/BSS transformation that will drive faster service rollout, streamline end-to-end business processes, and improve the customer experience for more than 27 million subscribers. A fully-owned subsidiary of América Móvil, Claro Colombia will deploy a range of Ericsson solutions to replace its legacy OSS/BSS architecture, with Ericsson serving as prime integrator. The deployment targets IT architecture and end-to-end business process transformation to enable self-care services and improved customer service. The deployment of Ericsson OSS/BSS solutions is part of a multi-vendor project, and will enable Claro Colombia to optimize and automate back-office functions - such as rating and billing. It will also provide 360-degree subscriber views to customer service representatives. For customers, the transformation will support self-care options and high-quality user experiences. Claro Colombia will be able to provide quicker and more agile services to its 27 million subscribers in the country, and take the next step toward becoming a digital operator. Carlos Zenteno, President of Claro Colombia, says: "Our priority is to offer the best experience for our customers and Ericsson will be an important ally in our digital transformation projects. We have high expectations on Ericsson's abilities and experience in integrating the elements that will help us to simplify our processes and improve our execution." Nicolas Brancoli, Vice President, Latin America and Caribbean, Ericsson, says: "We have been working for more than a year to show the main benefits of this enormous transformation project. We have the portfolio and experts to enable Claro Colombia to succeed in their digital strategy." To meet customer demand, operators need to continue improving the customer experience, capture new revenues, and drive business efficiencies. Ericsson is enabling operators to meet changing demands with a comprehensive, unified OSS and BSS product suite, as well as world-class consulting, systems integration and managed services capabilities. Claro is the mobile telecommunications operator with the largest coverage in Colombia. It carries its 2G, 3G and 4G signal to 1,113 municipalities in the country, with a network of more than 5,650 base stations, and has more than 27 million users who have chosen it as their mobile voice and data services operator. Claro also offers fixed telephony, broadband internet and closed television services. Claro Colombia is a subsidiary of América Móvil, S.A.B. Of C.V. BMV: AMX [NYSE: AMX]. [NASDAQ: AMOV] [LATIBEX: XAMXL], the leading provider of telecommunications services in Latin America with operations in 18 countries in the Americas. The company is present in Argentina, Brazil, Chile, Colombia, Costa Rica, Dominican Republic, Ecuador, El Salvador, Guatemala, Honduras, Nicaragua, Panama, Paraguay, Peru, Puerto Rico and Uruguay. For media kits, backgrounders and high-resolution photos, please visit www.ericsson.com/press Ericsson is the driving force behind the Networked Society - a world leader in communications technology and services. Our long-term relationships with every major telecom operator in the world allow people, business and society to fulfill their potential and create a more sustainable future. Our services, software and infrastructure - especially in mobility, broadband and the cloud - are enabling the telecom industry and other sectors to do better business, increase efficiency, improve the user experience and capture new opportunities. With approximately 115,000 professionals and customers in 180 countries, we combine global scale with technology and services leadership. We support networks that connect more than 2.5 billion subscribers. Forty percent of the world's mobile traffic is carried over Ericsson networks. And our investments in research and development ensure that our solutions - and our customers - stay in front. Founded in 1876, Ericsson has its headquarters in Stockholm, Sweden. Net sales in 2015 were SEK 246.9 billion (USD 29.4 billion). Ericsson is listed on NASDAQ OMX stock exchange in Stockholm and the NASDAQ in New York. FOR FURTHER INFORMATION, PLEASE CONTACT
Frouard J.,Claro |
Compere A.,University of Namur
Icarus | Year: 2012
The stability of the (87) Sylvia system and of the neighborhood of its two satellites is investigated. We use numerical integrations considering the non-sphericity of Sylvia, as well as the mutual perturbation of the satellites and the solar perturbation. Two numerical models have been used, which describe respectively the short and long-term evolution of the system. We show that the actual system is in a deeply stable zone, but surrounded by both fast and secular chaotic regions due to mean-motion and evection resonances. We then investigate how tidal and BYORP effects modify the location of the system over time with respect to the instability zones. The conclusion is that the system will cross the evection resonance before 1. Gyr.We generalize this study to other known triple systems, investigate possible evolutions of the systems under tidal and BYORP effects, and discuss their distance from instability regions. In particular, it is possible to show how systems in a joint opposing evolution can be destroyed depending on the masses of the satellites and their dissipative parameters. © 2012 Elsevier Inc..
Applied Radiation and Isotopes | Year: 2011
This paper describes the natural radioactivity of groundwater occurring in sedimentary (Bauru and Guarani) and fractured rock (Serra Geral) aquifer systems in the Paraná sedimentary basin, South America that is extensively used for drinking purposes, among others. The measurements of gross alpha and gross beta radioactivity as well the activity concentration of the natural dissolved radionuclides 40K, 238U, 234U, 226Ra, 222Rn, 210Po and 210Pb were held in 80 tubular wells drilled in 21 municipalities located at São Paulo State and its border with Mato Grosso do Sul State in Brazil. Most of the gross alpha radioactivity data were below 1mBq/L, whereas values exceeding the gross beta radioactivity detection limit of 30mBq/L were found. The radioelement solubility in the studied systems varied according to the sequence radon>radium>other radionuclides and the higher porosity of sandstones relatively to basalts and diabases could justify the enhanced presence of dissolved radon in the porous aquifer. The implications of the data obtained in terms of standards established for defining the drinking water quality have also been discussed. The population-weighted average activity concentration for these radionuclides was compared to the guideline value of 0.1mSv/yr for the total effective dose and discussed in terms of the choice of the dose conversion factors. © 2011 Elsevier Ltd.
Fernandes R.A.,Claro |
Hypertension Research | Year: 2010
Epidemiological studies have shown high rates of occurrence of arterial hypertension and type 2 diabetes mellitus among adults, and early preventive actions are extremely relevant for public policy strategies. The purpose of this study was to analyze the relationship between the prevalence of arterial hypertension and type 2 diabetes in adulthood and physical activity (currently and in childhood/adolescence). A retrospective study was carried out from March to November of 2009. Data were collected through interviews, and both diseases were assessed through self-report and confirmed by previous medical diagnosis. Current physical activity and that performed in childhood (7-10 years old) and adolescence (11-17 years old) were analyzed. Of the 1436 adults analyzed in this survey, ∼ 61% were women (n=881). Respondents' ages ranged from 18 to 94.8 years, and 20.2% of the total participants were ≥65 years old. Our results show that men (18%) were more physically active than women (9.4%), whereas younger respondents and those with more formal education exhibited greater physical activity levels (P≤0.001). Obese subjects presented lower physical activity levels (P=0.027). Physical activity in youth was associated with lower rates of occurrence of arterial hypertension (odds ratio (OR)=0.42 (95% confidence interval (CI)=0.29-0.62)) and type 2 diabetes mellitus (OR0.29 (95% CI=0.15-0.56)) in adulthood, but current physical activity was not related to these outcomes. Our study reveals a positive relationship between early physical activity in both childhood and adolescence and lower rates of occurrence of endocrine and cardiovascular diseases in adulthood. © 2010 The Japanese Society of Hypertension All rights reserved.
Almeida E.J.R.,Claro |
Chemosphere | Year: 2014
Azo dyes are an important class of environmental contaminants and are characterized by the presence of one or more azo bonds (N. N. ) in their molecular structure. Effluents containing these compounds resist many types of treatments due to their molecular complexity. Therefore, alternative treatments, such as biosorption and biodegradation, have been widely studied to solve the problems caused by these substances, such as their harmful effects on the environment and organisms. The aim of the present study was to evaluate biosorption and biodegradation of the azo dye Procion Red MX-5B in solutions with the filamentous fungi Aspergillus niger and Aspergillus terreus. Decolorization tests were performed, followed by acute toxicity tests using Lactuca sativa seeds and Artemia salina larvae. Thirty percent dye removal of the solutions was achieved after 3. h of biosorption. UV-Vis spectroscopy revealed that removal of the dye molecules occurred without major molecular changes. The acute toxicity tests confirmed lack of molecular degradation following biosorption with A. niger, as toxicity to L. sativa seed reduced from 5% to 0%. For A. salina larvae, the solutions were nontoxic before and after treatment. In the biodegradation study with the fungus A. terreus, UV-Vis and FTIR spectroscopy revealed molecular degradation and the formation of secondary metabolites, such as primary and secondary amines. The biodegradation of the dye molecules was evaluated after 24, 240 and 336. h of treatment. The fungal biomass demonstrated considerable affinity for Procion Red MX-5B, achieving approximately 100% decolorization of the solutions by the end of treatment. However, the solutions resulting from this treatment exhibited a significant increase in toxicity, inhibiting the growth of L. sativa seeds by 43% and leading to a 100% mortality rate among the A. salina larvae. Based on the present findings, biodegradation was effective in the decolorization of the samples, but generated toxic metabolites, while biosorption was effective in both decolorization and reducing the toxicity of the solutions. © 2014 .
Environmental Earth Sciences | Year: 2013
The radioactivity due to 238U and 234U in three aquifer systems occurring within the Paraná sedimentary basin, South America, has been investigated. Uranium is much less dissolved from fractured igneous rocks than from the porous sedimentary rocks as indicated by the U-mobility coefficients between 7. 6 × 10-6 and 1. 2 × 10-3 g cm-3. These values are also compatible with the U preference ratios relative to Na, K, Ca, Mg and SiO2, which showed that U is never preferentially mobilized in the liquid phase during the flow occurring in cracks, fissures, fractures and faults of the igneous basaltic rocks. Experimental dissolution of diabase grains on a time-scale laboratory has demonstrated that the U dissolution appeared to be a two-stage process characterized by linear and second-order kinetics. The U dissolution rate was 8 × 10-16 mol m-2 s-1 that is within the range of 4 × 10-16-3 × 10-14 mol m-2 s-1 estimated for other rock types. The 234U/238U activity ratio of dissolved U in solutions was higher than unity, a typical result expected during the water-rock interactions when preferential 234U-leach from the rock surfaces takes place. Some U-isotopes data allowed estimating 320 ka for the groundwater residence time in a sector of a transect in São Paulo State. A modeling has been also realized considering all U-isotopes data obtained in Bauru (35 samples), Serra Geral (16 samples) and Guarani (29 samples) aquifers. The results indicated that the Bauru aquifer waters may result from the admixture of waters from Guarani (1. 5 %) and Serra Geral (98. 5 %) aquifers. © 2012 Springer-Verlag.
Petesse M.L.,Claro |
Ecological Engineering | Year: 2012
Measurements of biotic homogenization are important for ascertaining the nature and extent of human impacts on biodiversity, especially in relation to habitat alteration, species introductions and water quality degradation. All of these impacts are typical of impounded systems. Our objectives in this study were to investigate the increasing biotic homogenization and the impacts of introduced species in the Tietê cascade reservoir system (State of São Paulo, Brazil). Biotic homogenization is the replacement of local biota by non-indigeonous species, leading to a gradual increase in biotic similarity over time. In this study, the decades analyzed (1980-89, 1990-99 and 2000-2009), revealed the progressive loss of the native species in the system. We used Jaccard's coefficient to measure the changes in biotic homogeneity across decades. In the first comparison (2000s vs. 1980s), the predominant process observed was differentiation, meaning that the biotic assemblages, in the sequence of five reservoirs studied, became more dissimilar. These changes were related to the extirpation of common species from reservoirs. In the second comparison period (2000s vs. 1990s), we observed a tendency towards biotic homogenization, meaning that the number of species in common among reservoirs was increasing. This shift was related to the loss of unique native species and the progressive environmental maturation of each reservoir. The process of homogenization may continue as the reservoirs age and as introduced fish species are dispersed and native species are displaced. For example, we observed the replacement of Geophagus brasiliensis (native) by Geophagus surinamensis (non-native) in the downstream reservoirs, likely due to the introduction of non-native predators (Cichlidae spp.). © 2011 Elsevier B.V.
Environmental Earth Sciences | Year: 2012
This investigation was carried out within the Paraná sedimentary basin, Brazil, and involved the sampling of 80 pumped tubular wells for evaluating the hydrochemistry in three aquifer systems (Bauru, Serra Geral and Guarani) occurring in 21 localities of São Paulo and Mato do Grosso Sul states. The Guarani aquifer of Triassic-Jurassic age has continental dimensions and extends over some 1. 2 million km2 within the Paraná basin. A thick (up to 1,500 m) basaltic package of the Serra Geral Formation overlies this aquifer that is covered by Cretaceous sediments of the Bauru Group. Major hydrochemical data were obtained and compared in each aquifer system, allowing the establishment of the principal trends among the parameters analyzed. The redox potential Eh decreased according to the pH increase in the three aquifers. A consistent database has been assured from expected relationships found for typical parameters commonly evaluated in hydrogeochemical surveys. Thus, direct relationships of conductivity with ionic strength (IS) were determined and, despite bicarbonate, assumed an important role in justifying such trends; other direct significant correlations involving IS were also identified with Na+, Cl-, F- and SO4 2-. Precipitation of carbonates was evidenced by opposite relations among CO3 2-, Ca2+ and Mg2+ that are strongly linked to the temperature effects on Ca2+ and Mg2+ dissolution as often reported from theoretical constraints. © 2012 Springer-Verlag.