1,401 research outputs found

    Data Preservation at LEP

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    The four LEP experiments ALEPH, DELPHI, L3 and OPAL successfully recorded e+e- collision data during the years 1989 to 2000. As part of the ordinary evolution in High Energy Physics, these experiments can not be repeated and their data is therefore unique. This article briefly reviews the data preservation efforts undertaken by the four experiments beyond the end of data taking. The current status of the preserved data and associated tools is summarised.Comment: 7 pages, contribution to proceedings of the "First Workshop on Data Preservation and Long Term Analysis in HEP

    Stand zur IT-Sicherheit deutscher Stromnetzbetreiber : technischer Bericht

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    Innerhalb des Forschungsprojektes „Sichere Informationsnetze bei kleinen und mittleren Energieversorgern“ (SIDATE) wurde eine Umfrage zum Stand der IT-Sicherheit bei deutschen Stromnetzbetreibern durchgeführt. Das Projekt selbst beschäftigt sich mit der Informations- Sicherheit bei kleinen und mittleren Energieversorgern. Zur Durchführung der Umfrage wurden alle 881 im August 2016 bei der Bundesnetzagentur gelisteten Betreiber angeschrieben. In dem Umfragezeitraum vom 1. September 2016 bis zum 15. Oktober 2016 antworten 61 (6.9%) der Betreiber. Der Fragebogen fokussiert die Umsetzung der rechtlichen Anforderungen und die Implementierung eines Informationssicherheitsmanagementsystems (ISMS). Weiterhin wurden Fragen zu dem Leitsystem, Netzaufbau, Prozessen, organisatorischen Strukturen und der Büro-IT gestellt

    Absolute frequency measurement of the magnesium intercombination transition 1S03P1^1S_0 \to ^3P_1

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    We report on a frequency measurement of the (3s2)1S0(3s3p)3P1(3s^2)^1S_0\to(3s3p)^3P_1 clock transition of 24^{24}Mg on a thermal atomic beam. The intercombination transition has been referenced to a portable primary Cs frequency standard with the help of a femtosecond fiber laser frequency comb. The achieved uncertainty is 2.5×10122.5\times10^{-12} which corresponds to an increase in accuracy of six orders of magnitude compared to previous results. The measured frequency value permits the calculation of several other optical transitions from 1S0^1S_0 to the 3PJ^3P_J-level system for 24^{24}Mg, 25^{25}Mg and 26^{26}Mg. We describe in detail the components of our optical frequency standard like the stabilized spectroscopy laser, the atomic beam apparatus used for Ramsey-Bord\'e interferometry and the frequency comb generator and discuss the uncertainty contributions to our measurement including the first and second order Doppler effect. An upper limit of 3×10133\times10^{-13} in one second for the short term instability of our optical frequency standard was determined by comparison with a GPS disciplined quartz oscillator.Comment: 8 pages, 8 figure

    Interaction of Climate Change with Effects of Conspecific and Heterospecific Density on Reproduction

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    We studied the relationship between temperature and the coexistence of great titParus majorand blue titCyanistes caeruleus, breeding in 75 study plots across Europe and North Africa. We expected an advance in laying date and a reduction in clutch size during warmer springs as a general response to climate warming and a delay in laying date and a reduction in clutch size during warmer winters due to density-dependent effects. As expected, as spring temperature increases laying date advances and as winter temperature increases clutch size is reduced in both species. Density of great tit affected the relationship between winter temperature and laying date in great and blue tit. Specifically, as density of great tit increased and temperature in winter increased both species started to reproduce later. Density of blue tit affected the relationship between spring temperature and blue and great tit laying date. Thus, both species start to reproduce earlier with increasing spring temperature as density of blue tit increases, which was not an expected outcome, since we expected that increasing spring temperature should advance laying date, while increasing density should delay it cancelling each other out. Climate warming and its interaction with density affects clutch size of great tits but not of blue tits. As predicted, great tit clutch size is reduced more with density of blue tits as temperature in winter increases. The relationship between spring temperature and density on clutch size of great tits depends on whether the increase is in density of great tit or blue tit. Therefore, an increase in temperature negatively affected the coexistence of blue and great tits differently in both species. Thus, blue tit clutch size was unaffected by the interaction effect of density with temperature, while great tit clutch size was affected in multiple ways by these interactions terms.Institute of Biology of Karelian Research Centre 0218-2019-0080Academy of Finland 265859Ministerio de Economía y Competitividad CGL-2016-79568-C3-3-

    Effects of Interspecific Coexistence on Laying Date and Clutch Size in Two Closely Related Species of Hole-nesting Birds

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    Coexistence between great tits Parus major and blue tits Cyanistes caeruleus, but also other hole-nesting taxa, constitutes a classic example of species co-occurrence resulting in potential interference and exploitation competition for food and for breeding and roosting sites. However, the spatial and temporal variations in coexistence and its consequences for competition remain poorly understood. We used an extensive database on reproduction in nest boxes by great and blue tits based on 87 study plots across Europe and Northern Africa during 1957–2012 for a total of 19,075 great tit and 16,729 blue tit clutches to assess correlative evidence for a relationship between laying date and clutch size, respectively, and density consistent with effects of intraspecific and interspecific competition. In an initial set of analyses, we statistically controlled for a suite of site-specific variables. We found evidence for an effect of intraspecific competition on blue tit laying date (later laying at higher density) and clutch size (smaller clutch size at higher density), but no evidence of significant effects of intraspecific competition in great tits, nor effects of interspecific competition for either species. To further control for site-specific variation caused by a range of potentially confounding variables, we compared means and variances in laying date and clutch size of great and blue tits among three categories of difference in density between the two species. We exploited the fact that means and variances are generally positively correlated. If interspecific competition occurs, we predicted a reduction in mean and an increase in variance in clutch size in great tit and blue tit when density of heterospecifics is higher than the density of conspecifics, and for intraspecific competition, this reduction would occur when density of conspecifics is higher than the density of heterospecifics. Such comparisons of temporal patterns of means and variances revealed evidence, for both species, consistent with intraspecific competition and to a smaller extent with interspecific competition. These findings suggest that competition associated with reproductive behaviour between blue and great tits is widespread, but also varies across large spatial and temporal scales. © 2018 The Authors. Journal of Animal EcologyAcademy of Finland 26585

    Stand zur IT-Sicherheit deutscher Stromnetzbetreiber : technischer Bericht : aktualisierte Version

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    Innerhalb des Forschungsprojektes „Sichere Informationsnetze bei kleinen und mittleren Energieversorgern“ (SIDATE) wurde eine Umfrage zum Stand der IT-Sicherheit bei deutschen Stromnetzbetreibern durchgeführt. Das Projekt selbst beschäftigt sich mit der Informations- Sicherheit bei kleinen und mittleren Energieversorgern. Zur Durchführung der Umfrage wurden alle 881 im August 2016 bei der Bundesnetzagentur gelisteten Betreiber angeschrieben. In dem Umfragezeitraum vom 1. September 2016 bis zum 15. Oktober 2016 antworten 61 (6.9%) der Betreiber. Der Fragebogen fokussiert die Umsetzung der rechtlichen Anforderungen und die Implementierung eines Informationssicherheitsmanagementsystems (ISMS). Weiterhin wurden Fragen zu dem Leitsystem, Netzaufbau, Prozessen, organisatorischen Strukturen und der Büro-IT gestellt

    IT security status of German energy providers : technical report

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    As part of the research project “Secure information networks of small- and medium-sized energy providers” (SIDATE), a survey about the IT security status of German energy providers was conducted. The project itself is focused on the IT security of small- and medium-sized energy providers. In August 2016, 881 companies listed by the Federal Network Agency were approached. Between, September 1st 2016 and October 15th 2016, 61 (6.9%) of the companies replied. The questionnaire focuses on the implementation of the regulatory requirements and on the implementation of an information security management system (ISMS). Additionally, questions about the energy control system, the network structure, processes, organisational structures, and the IT department were asked. Questions were asked in German, so all questions and answers are translated for this report

    Formation dry-out from CO2 injection into saline aquifers: Part 1, Effects of solids precipitation and their mitigation

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    Injection of CO{sub 2} into saline aquifers may cause formation dry-out and precipitation of salt near the injection well, which may reduce formation porosity, permeability, and injectivity. This paper uses numerical simulation to explore the role of different processes and parameters in the salt precipitation process and to examine injection strategies that could mitigate the effects. The main physical mechanisms affecting the dry-out and salt precipitation process include (1) displacement of brine away from the injection well by injected CO{sub 2}, (2) dissolution (evaporation) of brine into the flowing CO{sub 2} stream, (3) upflow of CO{sub 2} due to gravity effects (buoyancy), (4) backflow of brine toward the injection point due to capillary pressure gradients that oppose the pressure gradient in the CO{sub 2}-rich ('gas') phase, and (5) molecular diffusion of dissolved salt. The different mechanisms operate on a range of spatial scales. CO{sub 2} injection at constant rate into a homogeneous reservoir with uniform initial conditions is simulated in 1-D radial geometry, to resolve multiscale processes by taking advantage of the similarity property, i.e., the evolution of system conditions as a function of radial distance R and time t depends only on the similarity variable R{sup 2}/t. Simulations in 2-D vertical cross sections are used to examine the role of gravity effects. We find that counterflow of CO{sub 2} and brine can greatly increase aqueous phase salinity and can promote substantial salt precipitation even in formations with low dissolved solids. Salt precipitation can accentuate effects of gravity override. We find that injecting a slug of fresh water prior to commencement of CO{sub 2} injection can reduce salt precipitation and permeability loss near the injection well
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