1,188 research outputs found

    CERN GSM monitoring system

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    As a result of the tremendous development of GSM services over the last years, the number of related services used by organizations has drastically increased. Therefore, monitoring GSM services is becoming a business critical issue in order to be able to react appropriately in case of incident. In order to provide with GSM coverage all the CERN underground facilities, more than 50 km of leaky feeder cable have been deployed. This infrastructure is also used to propagate VHF radio signals for the CERN’s fire brigade. Even though CERN’s mobile operator monitors the network, it cannot guarantee the availability of GSM services, and for sure not VHF services, where signals are carried by the leaky feeder cable. So, a global monitoring system has become critical to CERN. In addition, monitoring this infrastructure will allow to characterize its behaviour over time, especially with LHC operation. Given that commercial solutions were not yet mature, CERN developed a system based on GSM probes and an application server which collects data from them via the CERN GPRS network. By placing probes in strategic locations and comparing measurements between probes, it is possible now possible to determine if there is a GSM or VHF problem on one leaky feeder cable segment. This system has been successfully working for several months in underground facilities, allowing CERN to inform GSM users and fire brigade in case of incidents

    Centro de servicios de emergencia Tumbaco-Cumbayá

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    La arquitectura como seguridad social es la propuesta del proyecto. Los elementos a considerar en este estudio son los siguientes: el contexto, historia, lugar y los problemas morfológicos. Estos son los componentes para la creación de un centro de emergencias; donde el edificio se convierta en un hecho urbano. Para entender al edificio como un hecho urbano debemos evocar la memoria del lugar y los elementos que lo han constituido en el tiempo, solo así se entenderá el lugar (edificio) como transición e interacción dentro de un programa. El lugar escogido y su locación son elementos importantes debido al radio de intervención para el proyecto. Su locación debe ser como un puente en el cual el centro aparezca como un ícono de unión y control entre los centros poblados de Tumbaco y Cumbayá. Pare defender este argumento debe entender a este puente (lugar) como un signo concreto del espacio, símbolo del pasado y lo contemporáneo

    Superparamagnetic particles in ZSM-5-type ferrisilicates

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    As-synthesized, low iron content, ferrisilicates of ZSM-5-type contain well-separated Fe(III) ions in a tetrahedral environment and display paramagnetic behavior. After hydrothermal treatment, the iron ions are partially extracted from the framework, generating nanosize iron oxide or oxyhydroxide ferrimagnetic particles. This process has been studied by transmission electron microscopy (TEM), Mossbauer spectroscopy, magnetic ac susceptibility (chi(ac)), and field dependent magnetization, on samples containing up to 6.7 wt. % Fe. The experiments evidence the growth of nonaggregated particles, with a typical size around 3 nm, presumably located at the surface of the ferrisilicate crystallites, From a thorough granulometric analysis involving TEM and chi(ac) data, it is concluded that, in the range from 1.5 to 4.6 wt. % Fe, the particle size distributions are significantly independent of the iron content

    Circuit architecture explains functional similarity of bacterial heat shock responses

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    Heat shock response is a stress response to temperature changes and a consecutive increase in amounts of unfolded proteins. To restore homeostasis, cells upregulate chaperones facilitating protein folding by means of transcription factors (TF). We here investigate two heat shock systems: one characteristic to gram negative bacteria, mediated by transcriptional activator sigma32 in E. coli, and another characteristic to gram positive bacteria, mediated by transcriptional repressor HrcA in L. lactis. We construct simple mathematical model of the two systems focusing on the negative feedbacks, where free chaperons suppress sigma32 activation in the former, while they activate HrcA repression in the latter. We demonstrate that both systems, in spite of the difference at the TF regulation level, are capable of showing very similar heat shock dynamics. We find that differences in regulation impose distinct constrains on chaperone-TF binding affinities: the binding constant of free sigma32 to chaperon DnaK, known to be in 100 nM range, set the lower limit of amount of free chaperon that the system can sense the change at the heat shock, while the binding affinity of HrcA to chaperon GroE set the upper limit and have to be rather large extending into the micromolar range.Comment: 17 pages, 5 figure

    Lanthanides in granulometric fractions of Mediterranean soils. Can they be used as fingerprints of provenance?

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    Highlights Are lanthanides from fine sand and clay genetically related to the geological materials? Lanthanide concentrations of fine sand and clay fit chronofunctions Pearson's r of lanthanide couples decreases when separation increases in the periodic table Free forms of clay are scavengers of lanthanides and concentrate HREE and ceriumSample preparation and chemical analysis were conducted by Emma Humphreys-Williams and Stanislav Strekopytov (Imaging and Analysis Centre, Natural History Museum, London, UK). This work was supported by a grant from Ministerio de Economía, Industria y Competitividad de España (‘Tipologías de Suelos Mediterráneos versus Cuarzo. En la frontera del conocimiento edafogenético’; Ref. CGL2016-80308-P). The authors thank Professor Margaret A. Oliver, an anonymous editor and two anonymous reviewers for helpful comments and suggestions that improved the final manuscript. We also thank Robert Abrahams (Bsc) for revising the English language.There is geochemical interest in the lanthanides because they behave like a group that is closely related to the parent materials during surface processes, although they also undergo fractionation as a result of supergene dynamics. We analysed lanthanide concentrations (ICPms) in the granulometric fractions fine sand, clay and free forms of clay (FFclay‐CDB and FFclay‐Ox: extracted with citrate‐dithionite‐sodium bicarbonate and with ammonium oxalate, respectively) from a soil chronosequence of Mediterranean soils. There was a relative enrichment of heavy rare earth elements (HREE) in the clay fraction and its free forms with respect to fine sand. The clay free forms behaved as scavengers of lanthanides, and oxidative scavenging of cerium (Ce) in FFclay‐CDB was also detected. Lanthanide concentrations (lanthanum to gadolinium in fine sand; terbium to lutetium in clay) varied with soil age, and chronofunctions were established. There was a strong positive collinearity between most of the lanthanide concentrations. Furthermore, the value of the correlation index (Pearson's r ) of the concentrations between couples of lanthanides (r CLC) decreased significantly with increasing separation between the elements in the periodic table; this has never been described in soils. Several geochemical properties and indices in the fine sand and clay soil fractions and in the geological materials of the Guadalquivir catchment showed, on the one hand, a genetic relation between them all, enabling the lanthanides to be used as fingerprints of provenance; on the other hand, fractionation between fine sand and clay showed these are actively involved in soil lanthanide dynamics.Secretaría de Estado de Investigación, Desarrollo e Innovación. Grant Number: CGL2016‐80308‐

    The lower limit of pitch perception for pure tones and low-frequency complex sounds

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    The lower limit of pitch (LLP) perception was explored for pure tones, sinusoidally amplitude-modulated (SAM) tones with a carrier frequency of 125 Hz, and trains of 125-Hz tone pips, using an adaptive procedure to estimate the lowest repetition rate for which a tonal/humming quality was heard. The LLP was similar for the three stimulus types, averaging 19 Hz. There were marked individual differences, which were correlated to some extent across stimulus types. The pure-tone stimuli contained a single resolved harmonic, whereas the SAM tones and tone-pip trains contained only unresolved components, whose frequencies did not necessarily form a harmonic series. The similarity of the LLP across stimulus types suggests that the LLP is determined by the repetition period of the sound for pure tones, and the envelope repetition period for complex stimuli. The results are consistent with the idea that the LLP is determined by a periodicity analysis in the auditory system, and that the longest time interval between waveform or envelope peaks for which this analysis can be performed is approximately 53 ms

    Methods, results and policy implications of poverty and food security mapping assessments

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    The importance of poverty reduction to the world development agenda has motivated greater interest in the geographic dimensions of poverty and food security. This special issue of Food Policy includes examples of poverty and food security mapping used to support policy development in agricultural and rural areas. The volume includes eight country case studies and one cross-country comparison that illustrate advances in our capacity to assess welfare over large areas and at detailed spatial resolutions. Poverty mapping facilitates assessments of the role of environmental factors on the broad spatial pattern of poverty and food security. Evaluating proximity and accessibility in welfare outcomes can improve our knowledge of poverty patterns and processes. Spatial statistics can enhance our understanding of geographic and neighbourhood effects on poverty and food security outcomes. The development of effective policies requires increased collaboration among stakeholders, researchers and policy makers in constructing and using poverty and food security maps

    Algorithms For Extracting Timeliness Graphs

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    We consider asynchronous message-passing systems in which some links are timely and processes may crash. Each run defines a timeliness graph among correct processes: (p; q) is an edge of the timeliness graph if the link from p to q is timely (that is, there is bound on communication delays from p to q). The main goal of this paper is to approximate this timeliness graph by graphs having some properties (such as being trees, rings, ...). Given a family S of graphs, for runs such that the timeliness graph contains at least one graph in S then using an extraction algorithm, each correct process has to converge to the same graph in S that is, in a precise sense, an approximation of the timeliness graph of the run. For example, if the timeliness graph contains a ring, then using an extraction algorithm, all correct processes eventually converge to the same ring and in this ring all nodes will be correct processes and all links will be timely. We first present a general extraction algorithm and then a more specific extraction algorithm that is communication efficient (i.e., eventually all the messages of the extraction algorithm use only links of the extracted graph)
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