SWACI is a research project of DLR supported by the State Government of Mecklenburg-Vorpommern. Radio signals, transmitted by modern communication and navigation systems may be heavily disturbed by space weather hazards. Thus, severe temporal and spatial changes of the electron density in the ionosphere may significantly degrade the signal quality of various radio systems which even may lead to a complete loss of the signal. By providing specific space weather information, in particular now- and forecast of the ionospheric state, the accuracy and reliability of impacted communication and navigation systems shall be improved. The total electron content (TEC) is defined as the integral of the electron density along the ray path between satellite and receiver. Thus, TEC provides the number of electrons per square meter. The most frequently used unit is 1TECU = 1x1016 electrons / m2. TEC is derived from dual frequency code and carrier phase measurements provided by Global Navigation Satellite Systems (GNSS). SWACI uses GPS measurements from various European GNSS networks such as the International GNSS Service (IGS), European Reference Frame (EUREF), Norwegian Mapping Authority (NMA), and ascos distributed by the Federal Agency of Cartography and Geodesy (BKG) Frankfurt. The global TEC maps are mainly created by using data provided by the International GNSS Service Real-Time Pilot Project (IGS-RTPP). To generate TEC maps of vertical TEC, the slant measurements have to be transformed to the vertical. In a first approximation the ionospheric range error in GNSS is proportional to TEC. These TEC maps are used to derive latitudinal and zonal gradients, rate of change of TEC (5 min increments), 27 days medians, hourly forecasts of TEC, and corresponding error estimates. Spatial resolution (latitude x longitude): 2 °x 2° (Europe), 2.5° x 5° (globally)
SWACI is a research project of DLR supported by the State Government of Mecklenburg-Vorpommern. Radio signals, transmitted by modern communication and navigation systems may be heavily disturbed by space weather hazards. Thus, severe temporal and spatial changes of the electron density in the ionosphere may significantly degrade the signal quality of various radio systems which even may lead to a complete loss of the signal. By providing specific space weather information, in particular now- and forecast of the ionospheric state, the accuracy and reliability of impacted communication and navigation systems shall be improved. The total electron content (TEC) is defined as the integral of the electron density along the ray path between satellite and receiver. Thus, TEC provides the number of electrons per square meter. The most frequently used unit is 1TECU = 1x1016 electrons / m2. TEC is derived from dual frequency code and carrier phase measurements provided by Global Navigation Satellite Systems (GNSS). SWACI uses GPS measurements from various European GNSS networks such as the International GNSS Service (IGS), European Reference Frame (EUREF), Norwegian Mapping Authority (NMA), and ascos distributed by the Federal Agency of Cartography and Geodesy (BKG) Frankfurt. The global TEC maps are mainly created by using data provided by the International GNSS Service Real-Time Pilot Project (IGS-RTPP). To generate TEC maps of vertical TEC, the slant measurements have to be transformed to the vertical. In a first approximation the ionospheric range error in GNSS is proportional to TEC. These TEC maps are used to derive latitudinal and zonal gradients, rate of change of TEC (5 min increments), 27 days medians, hourly forecasts of TEC, and corresponding error estimates. Spatial resolution (latitude x longitude): 2 °x 2° (Europe), 2.5° x 5° (globally)
SWACI is a research project of DLR supported by the State Government of Mecklenburg-Vorpommern. Radio signals, transmitted by modern communication and navigation systems may be heavily disturbed by space weather hazards. Thus, severe temporal and spatial changes of the electron density in the ionosphere may significantly degrade the signal quality of various radio systems which even may lead to a complete loss of the signal. By providing specific space weather information, in particular now- and forecast of the ionospheric state, the accuracy and reliability of impacted communication and navigation systems shall be improved. The total electron content (TEC) is defined as the integral of the electron density along the ray path between satellite and receiver. Thus, TEC provides the number of electrons per square meter. The most frequently used unit is 1TECU = 1x1016 electrons / m2. TEC is derived from dual frequency code and carrier phase measurements provided by Global Navigation Satellite Systems (GNSS). SWACI uses GPS measurements from various European GNSS networks such as the International GNSS Service (IGS), European Reference Frame (EUREF), Norwegian Mapping Authority (NMA), and ascos distributed by the Federal Agency of Cartography and Geodesy (BKG) Frankfurt. The global TEC maps are mainly created by using data provided by the International GNSS Service Real-Time Pilot Project (IGS-RTPP). To generate TEC maps of vertical TEC, the slant measurements have to be transformed to the vertical. In a first approximation the ionospheric range error in GNSS is proportional to TEC. These TEC maps are used to derive latitudinal and zonal gradients, rate of change of TEC (5 min increments), 27 days medians, hourly forecasts of TEC, and corresponding error estimates. Spatial resolution (latitude x longitude): 2 °x 2° (Europe), 2.5° x 5° (globally)
SWACI is a research project of DLR supported by the State Government of Mecklenburg-Vorpommern. Radio signals, transmitted by modern communication and navigation systems may be heavily disturbed by space weather hazards. Thus, severe temporal and spatial changes of the electron density in the ionosphere may significantly degrade the signal quality of various radio systems which even may lead to a complete loss of the signal. By providing specific space weather information, in particular now- and forecast of the ionospheric state, the accuracy and reliability of impacted communication and navigation systems shall be improved. The total electron content (TEC) is defined as the integral of the electron density along the ray path between satellite and receiver. Thus, TEC provides the number of electrons per square meter. The most frequently used unit is 1TECU = 1x1016 electrons / m2. TEC is derived from dual frequency code and carrier phase measurements provided by Global Navigation Satellite Systems (GNSS). SWACI uses GPS measurements from various European GNSS networks such as the International GNSS Service (IGS), European Reference Frame (EUREF), Norwegian Mapping Authority (NMA), and ascos distributed by the Federal Agency of Cartography and Geodesy (BKG) Frankfurt. The global TEC maps are mainly created by using data provided by the International GNSS Service Real-Time Pilot Project (IGS-RTPP). To generate TEC maps of vertical TEC, the slant measurements have to be transformed to the vertical. In a first approximation the ionospheric range error in GNSS is proportional to TEC. These TEC maps are used to derive latitudinal and zonal gradients, rate of change of TEC (5 min increments), 27 days medians, hourly forecasts of TEC, and corresponding error estimates. Spatial resolution (latitude x longitude): 2 °x 2° (Europe), 2.5° x 5° (globally)
SWACI is a research project of DLR supported by the State Government of Mecklenburg-Vorpommern. Radio signals, transmitted by modern communication and navigation systems may be heavily disturbed by space weather hazards. Thus, severe temporal and spatial changes of the electron density in the ionosphere may significantly degrade the signal quality of various radio systems which even may lead to a complete loss of the signal. By providing specific space weather information, in particular now- and forecast of the ionospheric state, the accuracy and reliability of impacted communication and navigation systems shall be improved. The total electron content (TEC) is defined as the integral of the electron density along the ray path between satellite and receiver. Thus, TEC provides the number of electrons per square meter. The most frequently used unit is 1TECU = 1x1016 electrons / m2. TEC is derived from dual frequency code and carrier phase measurements provided by Global Navigation Satellite Systems (GNSS). SWACI uses GPS measurements from various European GNSS networks such as the International GNSS Service (IGS), European Reference Frame (EUREF), Norwegian Mapping Authority (NMA), and ascos distributed by the Federal Agency of Cartography and Geodesy (BKG) Frankfurt. The global TEC maps are mainly created by using data provided by the International GNSS Service Real-Time Pilot Project (IGS-RTPP). To generate TEC maps of vertical TEC, the slant measurements have to be transformed to the vertical. In a first approximation the ionospheric range error in GNSS is proportional to TEC. These TEC maps are used to derive latitudinal and zonal gradients, rate of change of TEC (5 min increments), 27 days medians, hourly forecasts of TEC, and corresponding error estimates. Spatial resolution (latitude x longitude): 2 °x 2° (Europe), 2.5° x 5° (globally)
SWACI is a research project of DLR supported by the State Government of Mecklenburg-Vorpommern. Radio signals, transmitted by modern communication and navigation systems may be heavily disturbed by space weather hazards. Thus, severe temporal and spatial changes of the electron density in the ionosphere may significantly degrade the signal quality of various radio systems which even may lead to a complete loss of the signal. By providing specific space weather information, in particular now- and forecast of the ionospheric state, the accuracy and reliability of impacted communication and navigation systems shall be improved. The total electron content (TEC) is defined as the integral of the electron density along the ray path between satellite and receiver. Thus, TEC provides the number of electrons per square meter. The most frequently used unit is 1TECU = 1x1016 electrons / m2. TEC is derived from dual frequency code and carrier phase measurements provided by Global Navigation Satellite Systems (GNSS). SWACI uses GPS measurements from various European GNSS networks such as the International GNSS Service (IGS), European Reference Frame (EUREF), Norwegian Mapping Authority (NMA), and ascos distributed by the Federal Agency of Cartography and Geodesy (BKG) Frankfurt. The global TEC maps are mainly created by using data provided by the International GNSS Service Real-Time Pilot Project (IGS-RTPP). To generate TEC maps of vertical TEC, the slant measurements have to be transformed to the vertical. In a first approximation the ionospheric range error in GNSS is proportional to TEC. These TEC maps are used to derive latitudinal and zonal gradients, rate of change of TEC (5 min increments), 27 days medians, hourly forecasts of TEC, and corresponding error estimates. Spatial resolution (latitude x longitude): 2 °x 2° (Europe), 2.5° x 5° (globally)
SWACI is a research project of DLR supported by the State Government of Mecklenburg-Vorpommern. Radio signals, transmitted by modern communication and navigation systems may be heavily disturbed by space weather hazards. Thus, severe temporal and spatial changes of the electron density in the ionosphere may significantly degrade the signal quality of various radio systems which even may lead to a complete loss of the signal. By providing specific space weather information, in particular now- and forecast of the ionospheric state, the accuracy and reliability of impacted communication and navigation systems shall be improved. The total electron content (TEC) is defined as the integral of the electron density along the ray path between satellite and receiver. Thus, TEC provides the number of electrons per square meter. The most frequently used unit is 1TECU = 1x1016 electrons / m2. TEC is derived from dual frequency code and carrier phase measurements provided by Global Navigation Satellite Systems (GNSS). SWACI uses GPS measurements from various European GNSS networks such as the International GNSS Service (IGS), European Reference Frame (EUREF), Norwegian Mapping Authority (NMA), and ascos distributed by the Federal Agency of Cartography and Geodesy (BKG) Frankfurt. The global TEC maps are mainly created by using data provided by the International GNSS Service Real-Time Pilot Project (IGS-RTPP). To generate TEC maps of vertical TEC, the slant measurements have to be transformed to the vertical. In a first approximation the ionospheric range error in GNSS is proportional to TEC. These TEC maps are used to derive latitudinal and zonal gradients, rate of change of TEC (5 min increments), 27 days medians, hourly forecasts of TEC, and corresponding error estimates. Spatial resolution (latitude x longitude): 2 °x 2° (Europe), 2.5° x 5° (globally)
Das Projekt "Verotoxinogene E.coli-Staemme (VTEC/SLT-EC) bei Schlachttieren und in Lebensmitteln tierischen Ursprungs - Bestandsaufnahme und Aufklaerung von Infektionsketten beim Menschen mit immunologischen und molekularbiologischen Verfahren" wird vom Umweltbundesamt gefördert und von Bundesinstitut für gesundheitlichen Verbraucherschutz und Veterinärmedizin durchgeführt. Ein Teil der Magen-Darm-Infektionen kann von den sog. VTEC/EHEC-Bakterien (Verotoxinogene (shiga-like-toxin-producing)/Enterohaemorrhagische E.coli-Staemme (VTEC/SLT-EC) verursacht werden. Sie gehoeren zur grossen Gruppe der ubiquitaer vorkommenden E.coli. Sie werden bei Schlachttieren und Lebensmitteln tierischen Ursprungs angetroffen und koennen vom Tier ueber Lebensmittel auf den Menschen uebertragen werden. Das Vorhaben dient der Bestandsaufnahme und Aufklaerung von Infektionsketten beim Menschen mit immunologischen und molekularbiologischen Verfahren. Die bisher unzureichende Datenlage zu VTEC/EHEC-Erkrankungen soll verbessert werden. Ausserdem sind routinemaessige Untersuchungsverfahren zu entwickeln, um damit die Einfuehrung praxisfaehiger, spezifischer diagnostischer Methoden in den Untersuchungseinrichtungen zu unterstuetzen und zu koordinieren. Ziel des Vorhabens ist damit die weitere Verbesserung des gesundheitlichen Verbraucherschutzes, insbesondere: - die Etablierung fuer Lebensmitteluntersuchungen geeigneter, hochempfindlicher diagnostischer Verfahren zum Nachweis Verotoxin-bildender E.coli (VTEC) sowie Hilfe bei der unmittelbaren Einfuehrung solcher Nachweisverfahren in amtlichen Veterinaer- und Lebensmitteluntersuchungseinrichtungen; - die Bestandsaufnahme von Reservoiren der VTEC/STEC (EHEC) in und auf Schlachttieren und in Lebensmitteln; - Untersuchungen zur Aufklaerung von EHEC-Infektionsketten beim Menschen unter logistischen Voraussetzungen fuer die Zusammenarbeit der in der Bundesrepublik Deutschland foederal organisierten und strukturierten Untersuchungs- und Ueberwachungseinrichtungen. Das Forschungsvorhaben wurde im Bundesinstitut fuer gesundheitlichen Verbraucherschutz und Veterinaermedizin (BgVV) und unter dessen Federfuehrung erstellt. Die Untersuchungen wurden in der Zeit von August 1995 bis Februar 1998 durchgefuehrt.
Das Projekt "Isolierung von Escherichia coli Serovar O157H7 aus Rinderhackfleisch mit Dynabeads anti-E coli0157 im Modellversuch" wird vom Umweltbundesamt gefördert und von Justus-Liebig-Universität Gießen, Institut für Tierärztliche Nahrungsmittelkunde durchgeführt. Mikroorganismen wie E coli 0157H7 stellen eine haeufige Ursache fuer Lebensmittelinfektionen beim Menschen dar. In den letzten Jahren wurden unterschiedliche Nachweisverfahren wie auch die immunomagnetischen Separation (IMS) speziell fuer E coli 0157.H7 aus Lebensmitteln entwickelt. Diese Separationstechnik mit Dynabeads anti-E. coli 0157 sollte in diesem Forschungsvorhaben hinsichtlich der Nachweisgrenze, des Zeitaufwandes, der Anwendbarkeit fuer tiefgefrorene Proben und der Anreicherungs- und Subkultivierungsmedien untersucht werden. Dazu wurden Rinderhackfleischproben in unterschiedlichen Konzentrationen (ca. 1, 10 und 25 KbE/25g) mit einem E coli 0157H7-Stamm kuenstlich kontaminiert. Eine Haelfte der Probe wurde direkt untersucht, die andere Haelfte nach einer Lagerungszeit von acht Tagen bei minus 25 Grad Celsius. Es wurden jeweils die Wiederfindungsraten des Pruefstammes ermittelt. Dabei wurden zwei Anreicherungsmedien, bis zu drei Anreicherungszeiten (5 Stunde, 6 Stunden und 24 Stunden) und die nachfolgende Subkultivierung auf zwei Selektivmedien mit und ohne Durchfuehrung der IMS vergleichend untersucht. Es konnte sowohl fuer die Untersuchung des frischen als auch des gefroren gelagerten Hackfleisches gezeigt werden, dass mit der IMS unabhaengig von der jeweiligen Einmischkonzentrationen insgesamt deutlich bessere Ergebnisse als mt dem Vergleichsverfahren ohne IMS erzielt werden konnten. Die besten Ergebnisse wurden bei paralleler Anreicherung in beiden Naehrmedien, der IMS sowohl nach 6-stuendiger als auch nach 24-stuendiger Anreicherungszeit mit Subkultivierung auf beide Selektivmedien erzielt. Die IMS fuer E coli 0157H7 stellt fuer routinemaessige Laboruntersuchungen ein zuverlaessiges Nachweisverfahren mit hoher Sensitivitaet und Spezifitaet dar.
Das Projekt "Vergleichende Untersuchungen zur Einsatzfaehigkeit des ProSpecT Shiga-like Toxins I und II Microplate Assay bei Lebensmitteln tierischer Herkunft" wird vom Umweltbundesamt gefördert und von Justus-Liebig-Universität Gießen, Institut für Tierärztliche Nahrungsmittelkunde durchgeführt. Verotoxinbildende E coli-Staemme (VTEC) treten seit Anfang der achtziger Jahre weltweit als Ursache von Lebensmittelinfektionen auf. In den letzten Jahren wurden immunchemische Verfahren entwickelt, die den phaenotypischen Nachweis der Gesamtgruppe der VTEC ermoeglichen. In den eigenen Untersuchungen wurden zwei Testsysteme ('ProSpecT Shiga-like Toxins I and II'-ELISA, Genzyme Virotech GmbH, Ruesselsheim und 'Premier EHEC'-EIA, Hiss Diagnostics GmbH, Freiburg) hinsichtlich ihrer Einsatzfaehigkeit bei Lebensmitteln tierischer Herkunft vergleichend untersucht. Dazu wurden zunaechst in 54 Parallelansaetzen Hackfleischproben mit unterschiedlichen Einmischkonzentrationen drei verschiedener verotoxinbildender E coli-Staemme kuenstlich kontaminiert und nach Anreicherung in Brillantgruen-Galle-Laktose (BRILA) und modifizierter Trypton-Soja-Boullion und Novobiocin (mTSB+N) getestet. Anschliessend kamen native Rinderhackfleich- und Schaffleischproben zur Austestung. Saemtliche Versuchsansaetze wurden in der Polymerase-Ketten-Reaktion zur Erfassung des Virulenzfaktors Verotoxin untersucht. Im Rahmen der Einmischversuche konnte gezeigt werden, dass Einmmischkonzentrationen von kleiner 1 Koloniebildender Einheit/g Rinderhackfleisch in beiden Testsystemen zuverlaessig detektiert wurden. Hierbei als auch anlaesslich der Untersuchung der nativen Fleischproben stellte sich die Anreicherung in BRILA gegenueber der in mTSB+N als ueberlegen dar. Die besten Ergebnisse wurden durch Kombination der Testergebnisse beider Anreicherungsverfahren erzielt. So konnte unter Einbeziehung aller getesteten Fleischproben eine Sensivitaet von 95,7 Prozent fuer beide Testsysteme ermittelt werden.