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  • 1
    Publication Date: 2017-04-04
    Description: This paper aims at providing an overview of latest advances in space weather modeling in an operational environment in Europe, including both the introduction of new models and improvements to existing codes and algorithms that address the broad range of space weather’s prediction requirements from the Sun to the Earth. For each case, we consider the model’s input data, the output parameters, products or services, its operational status, and whether it is supported by validation results, in order to build a solid basis for future developments. This work is the output of the Sub Group 1.3 ‘‘Improvement of operational models’’ of the European Cooperation in Science and Technology (COST) Action ES0803 ‘‘Developing Space Weather Products and services in Europe’’ and therefore this review focuses on the progress achieved by European research teams involved in the action.
    Description: Published
    Description: A17
    Description: 3.9. Fisica della magnetosfera, ionosfera e meteorologia spaziale
    Description: N/A or not JCR
    Description: open
    Keywords: space weather ; modelling ; forecasting ; services ; space environment ; 01. Atmosphere::01.02. Ionosphere::01.02.03. Forecasts
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Annales geophysicae 16 (1998), S. 1434-1444 
    ISSN: 0992-7689
    Keywords: Electromagnetic theory ; Geomagnetic induction ; Auroral ionosphere
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The electromagnetic field due to ionospheric currents has to be known when evaluating space weather effects at the earth’s surface. Forecasting methods of these effects, which include geomagnetically induced currents in technological systems, are being developed. Such applications are time-critical, so the calculation techniques of the electromagnetic field have to be fast but still accurate. The contribution of secondary sources induced within the earth leads to complicated integral formulas for the field at the earth’s surface with a time-consuming computation. An approximate method of calculation based on replacing the earth contribution by an image source having mathematically a complex location results in closed-form expressions and in a much faster computation. In this paper we extend the complex image method (CIM) to the case of a more realistic electrojet system consisting of a horizontal line current filament with vertical currents at its ends above a layered earth. To be able to utilize previous CIM results, we prove that the current system can be replaced by a purely horizontal current distribution which is equivalent regarding the total (= primary + induced) magnetic field and the total horizontal electric field at the earth’s surface. The latter result is new. Numerical calculations demonstrate that CIM is very accurate and several magnitudes faster than the exact conventional approach.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Biological cybernetics 29 (1978), S. 159-166 
    ISSN: 1432-0770
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Computer Science , Physics
    Notes: Abstract An analysis of the model performance under normal and abnormal conditions is presented. The effects of changes in the alveolar ventilation rate on the inspiratory time, expiratory time, pause period, respiratory frequency, tidal volume, dead space volume and change in end expiratory level are considered. Moreover, theoretical predictions of the effects of added resistance loads are given. The results are displayed for three different values of the elastance. Comparisons with available experimental data show that the model predictions are in good accordance with observations under both normal and loaded conditions. None of the previous models have been able to reproduce the overall pattern of breathing as accurately as the present hierarchical model.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Biological cybernetics 29 (1978), S. 151-158 
    ISSN: 1432-0770
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Computer Science , Physics
    Notes: Abstract A model of the overall control of the breathing pattern is presented. The model has the structure of a two-level optimization problem where the lower level criteria determine the shape of the airflow during inspiration and expiration and the higher level criterion determines the values of the other control variables. The model's general formulation makes it possible to obtain predictions of far greater accuracy than before because the previous restrictive assumptions have been avoided by increasing the number of independent control variables. In this model the control variables are the inspiratory time, expiratory time, duration of the end expiratory pause, change in the end expiratory lung volume, the dead space volume, the tidal volume, and the airflow pattern during the cycle. The model's optimization problem has clear and unique minima with respect to each control variable over a wide range of parameter values. Thus the model can be used to predict the effects of various environmental changes.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Biological cybernetics 29 (1978), S. 143-149 
    ISSN: 1432-0770
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Computer Science , Physics
    Notes: Abstract A model of the control of the respiratory cycle pattern is presented in which the airflow shape is determined by a dynamic optimization problem. The inspiratory and expiratory phases have different performance criteria both of which are related to the oxygen cost of breathing, and to the minimization of tissue damage and control difficulties. The model successfully predicts various patterns of spontaneous breathing during both inspiration and expiration. The effects of applying elastic and resistive loads to the respiratory system can also be predicted. The model performance is in good agreement with the experimental observation that increasing resistance makes the airflow patterns more rectangular.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Annales geophysicae 13 (1995), S. 1187-1196 
    ISSN: 0992-7689
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract In addition to field observations and numerical models, geomagnetic induction effects can be studied by scaled analogue model experiments. We present here results of analogue model studies of the auroral electrojet with an Earth model simulating the Arctic Ocean and inland conductivity structures in northern Fennoscandia. The main elements of the analogue model used were salt water simulating the host rock, an aluminium plate corresponding to the ocean and graphite pieces producing the inland highly conducting anomalies. The electrojet was a time-harmonic line current flowing at a (simulated) height of 100 km above northern Fennoscandia. The period simulated was 9 min. The analogue model results confirmed the well-known rapid increase of the vertical field when the coast is approached from the continent. The increase of the horizontal field due to induced ocean currents was demonstrated above the ocean, as well as the essentially negligible effect of these currents on the horizontal field on the continent. The behaviour of the magnetic field is explained with a simple two-dimensional thin-sheet model. The range, or the adjustment distance, of the ocean effect inland was found to be some hundreds of kilometers, which also agrees with earlier results of the Siebert-Kertz separation of IMAGE magnetometer data. The modelled inland anomalies evidently had too large conductivities, but on the other hand, their influence decayed on scales of only some tens of kilometers. Analogue model results, thin-sheet calculations, and field observations show that the induction effect on the horizontal magnetic field Bx near the electrojet is negligible. On the other hand, the vertical component Bz is clearly affected by induced currents in the ocean. Evidence of this is the shift of the zero point of Bz 0-1° southwards from the maximum of Bx. The importance of these results are discussed, emphasizing the determination of ionospheric currents.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Surveys in geophysics 15 (1994), S. 383-408 
    ISSN: 1573-0956
    Keywords: geomagnetic variations ; geomagnetically induced currents ; GIC ; power systems
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract We consider geomagnetically induced currents (GICs) in power systems from the viewpoint of a geophysicist. Special attention is paid to the Finnish high-voltage power system, in which exact theoretical model calculations together with recordings have been performed for several years. We present several examples of theoretically computed GICs using different geophysical models for estimating the geoelectric field driving GICs. Statistical prediction of GICs is outlined referring to studies made in Finland. We show that a combination of GIC recordings at few sites with theoretical modelling of ionospheric currents and the earth's conductivity, and data of geomagnetic activity makes it possible to derive GIC statistics of the entire power system. Finally, we discuss requirements for a long-range prediction of GICs, which will obviously be a widely-studied topic in future.
    Type of Medium: Electronic Resource
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  • 8
  • 9
    Publication Date: 2015-09-12
    Description: Hearing loss and individual differences in normal hearing both have a substantial genetic basis. Although many new genes contributing to deafness have been identified, very little is known about genes/variants modulating the normal range of hearing ability. To fill this gap, we performed a two-stage meta-analysis on hearing thresholds (tested at 0.25, 0.5, 1, 2, 4, 8 kHz) and on pure-tone averages (low-, medium- and high-frequency thresholds grouped) in several isolated populations from Italy and Central Asia (total N = 2636). Here, we detected two genome-wide significant loci close to PCDH20 and SLC28A3 (top hits: rs78043697, P = 4.71E–10 and rs7032430, P = 2.39E–09, respectively). For both loci, we sought replication in two independent cohorts: B58C from the UK ( N = 5892) and FITSA from Finland ( N = 270). Both loci were successfully replicated at a nominal level of significance ( P 〈 0.05). In order to confirm our quantitative findings, we carried out RT-PCR and reported RNA-Seq data, which showed that both genes are expressed in mouse inner ear, especially in hair cells, further suggesting them as good candidates for modulatory genes in the auditory system. Sequencing data revealed no functional variants in the coding region of PCDH20 or SLC28A3 , suggesting that variation in regulatory sequences may affect expression. Overall, these results contribute to a better understanding of the complex mechanisms underlying human hearing function.
    Print ISSN: 0964-6906
    Electronic ISSN: 1460-2083
    Topics: Biology , Medicine
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  • 10
    Publication Date: 1978-01-01
    Print ISSN: 0340-1200
    Electronic ISSN: 1432-0770
    Topics: Biology , Computer Science , Physics
    Published by Springer
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