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  • 1
    Publication Date: 2023-12-15
    Description: Contrail ice nucleation and ice crystal loss during the vortex phase control ice crystal numbers in young contrails and can have a strong impact on the properties and the life cycle of contrail cirrus. For current soot number emissions, ice nucleation is controlled by the number of emitted soot particles and atmospheric conditions while the vortex phase loss depends predominantly on the nucleated ice crystal numbers and the ambient relative humidity. Initial ice crystal numbers after the vortex phase are close to the emitted soot particle number only for very low ambient temperatures (〈210 K) and for highly ice‐supersaturated conditions. Higher temperatures and lower relative humidities lead to significantly decreased ice crystal numbers. Global climate model simulations show that initial contrail ice crystal numbers per fuel mass are on average 50%–65% decreased relative to the soot number emission index in the extratropics and more in tropics. In the extratropics, this is mainly caused by a high ice crystal loss during the vortex phase and in the (sub)tropics and at lower flight levels by decreased ice nucleation. Simulated ice crystal numbers per newly formed contrail length agree well with in situ measurements over central Europe within the variability of present‐day soot number emissions. Our estimated global mean contrail cirrus radiative forcing (RF) for the year 2006 is 44 (31–49) mWm〈sup〉−2〈/sup〉, around 22% lower than estimated in a previous study. When reducing soot number emissions by 80%, RF decreases by 41%, slightly less than suggested by a recent study.
    Description: Plain Language Summary: Contrail cirrus are known to be a major contribution to the aviation climate impact connected with a large uncertainty. Earlier research has shown that the ice crystal number in newly formed contrails has a large impact on the average contrail cirrus climate impact. But the properties of newly formed contrails are not well captured within the climate models. We have improved the representation of the contrail formation processes in our contrail cirrus module within the ECHAM climate model by including parameterizations for contrail ice nucleation and the ice crystal survival in the vortex phase. We could show that young contrail properties agree well with available campaign measurements over central Europe, given the large variability in soot number emissions, when matching geographical locations, cruise level, and atmospheric variables. The improvements within our contrail cirrus parameterization lead to a decrease in our estimate of contrail cirrus radiative forcing by slightly more than 20% relative to our earlier estimates in which we prescribed constant initial ice crystal numbers. Furthermore, our improved model indicates that the decrease in the contrail cirrus climate impact due to introducing biofuels, which lead to a decrease in soot number emissions, is slightly smaller than estimated earlier.
    Description: Key Points: For current soot emissions, young contrail ice numbers are limited by vortex phase loss in extratropics and ice nucleation in tropics. Modeled young contrail ice crystal numbers agree well with measurements over Europe considering the variability of soot number emissions. Sensitivity of contrail cirrus radiative forcing to soot number emissions decreased if capturing variability in young contrail ice numbers.
    Description: Emission and Climate Impact of Alternative Fuels
    Description: Scientific Steering Committee
    Description: https://zenodo.org/record/6902742
    Description: https://www.qtiplot.com/
    Description: http://ferret.pmel.noaa.gov/Ferret/
    Keywords: ddc:551.5 ; contrail formation ; soot number emissions ; ice crystal numbers ; contrail cirrus properties ; radiative forcing
    Language: English
    Type: doc-type:article
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  • 2
    Electronic Resource
    Electronic Resource
    Copenhagen : International Union of Crystallography (IUCr)
    Acta crystallographica 50 (1994), S. 313-316 
    ISSN: 1600-5740
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    Journal of clinical periodontology 29 (2002), S. 0 
    ISSN: 1600-051X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background/aims: Periodontal infections with Actinobacillus actinomycetemcomitans seem to be refractory to conventional therapy. The aim of the present study was to test the in vitro susceptibilities of A. actinomycetemcomitans strains to a panel of seven orally administrable antibiotics.Methods: A total of 60 isolates of A. actinomycetemcomitans recovered from 43 individuals with gingivitis or periodontitis were tested. In addition, laboratory strains UP-6 and JP2 were analysed. The E-test was employed in order to determine minimal inhibitory concentrations (MIC) of antibiotics ampicillin/sulbactam, roxithromycin, azithromycin, doxycycline, metronidazole, ciprofloxacin, and moxifloxacin.Results: A. actinomycetemcomitans was highly susceptible to both fluoro-quinolones (MIC90 of 0.006 µg/mL of ciprofloxacin and 0.032 µg/mL of moxifloxacin). Good susceptibilities were found for ampicillin/sulbactam and doxycycline (MIC90 of 0.75 µg/mL and 1 µg/mL, respectively), and moderate susceptibilities for azithromycin (MIC90 of 3 µg/mL). Most strains were resistant to metronidazole and roxithromycin. Cluster analysis revealed two larger clusters of A. actinomycetemcomitans strains with the smaller cluster assembling isolates with significantly higher MICs of most antibiotics. Conclusions: Due to reported favourable pharmacokinetics, the fluoro-quinolone moxifloxacin appeared to be a promising candidate for adjunctive systemic antibiotic therapy in periodontal infections with A. actinomycetemcomitans.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Der Anaesthesist 48 (1999), S. 317-324 
    ISSN: 1432-055X
    Keywords: Schlüsselwörter Intubation ; Säuglinge ; Propofol ; Muskelrelaxanzien ; Key words Intubation ; Infants ; Propofol ; Muscle relaxants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Abstract The unwanted side effects of muscle relaxants used for anaesthesia in the newborn and infants resulted in a search for alternatives to atraumatic intubation (IN). The study was aimed to investigate conditions of intubation, time of intubation as well as changes in systolic, mean and diastolic blood pressure (RRs/RRm/RRd) and heart rate (HR) under the use of propofol (P) after narcosis induction by mask. Patients and methods: The study was approved by the local ethics committee. The data was analysed from 100 infants aged between 4 days and 56 weeks (weight 2110–9230 g) in the ASA I and II groups (Group [Gr] A and B both with 50 patients). In both groups induction was performed inhalationally with halothane (1.5–2.0 vol%) and pure oxygen. After that propofol for intubation was applied in a dose of 2 mg/kg i.v. In Gr A blood pressure and heart rate were registered at three measuring points (MP): MP 1=before P administration, MP 2=after P, MP 3=following intubation; in Gr B at MP 1 and MP 3. Additionally in Gr B the intubation time was recorded in seconds (t1=time after P administration to beginning of IN, t2=time after P administration to the end of the IN, t3=t2–t1). In both groups the conditions of intubation were assessed (score 1 – excellent, 2 – good, 3 – bad, 4 – impossible intubation). Results: The means of RRs/RRm/RRd/HR varied in Gr A at MP 2 by –11.20*/–9.18*/ –8.58*/–3.52 mmHg/bpm and at MP 3 by –2.74/–2.26/–2.04/+5.46 mmHg/bpm in comparison to MP 1 (p〈0.05=significant*). Compared to MP 1 in Gr B the mean values of RRs/RRm/RRd/HR varied at MP 3 by –0.89/+0.50/–0.80/+4.20* mmHg/bpm. T1 (mean, SD) was 10.88±3.52 seconds (s), t2 26.22±6.12 s, and t3 was therefore 15.78±6.28 s. Conditions of intubation were found to be excellent or good in both groups (Gr A and B [100 patients]: score 1=95x=95%, score 2=5x=5%). Conclusion: In the observation period, changes in heart rate stayed in the range of reference. In our opinion the excellent and good conditions for intubation, as well as the ultrashort drug-onset and intubation time demonstrate the good characteristics afforded by propofol to perform intubation in infancy.
    Notes: Zusammenfassung Unerwünschte Nebenwirkungen der Muskelrelaxanzien im Neugeborenen- und Säuglingsalter veranlassen weiterhin zur Suche nach Alternativen einer atraumatischen Intubation (IN). Ziel der vorliegenden Studie war es, die Intubationsbedingungen (IB) und -zeiten (IZ) sowie die Veränderungen von systolischem, mittlerem und diastolischem Blutdruck (RRs/RRm/RRd) und der Herzfrequenz (HF) unter Propofol (P) nach Einleitung mit Halothan zu untersuchen. Patienten und Methode: Die Studie wurde von der Ethikkommission der Universität Leipzig genehmigt. Zur Auswertung kamen die Daten von 100 Säuglingen im Alter von 4 Tagen bis 56 Wochen (Gewicht 2110–9230 g) der ASA-Gruppen I–II (Gruppe [Gr] A und B je n=50). Die Narkoseeinleitung erfolgte inhalativ mit Halothan/Sauerstoff (1,5–2 Vol.-%), danach wurden rasch 2 mg/kg KG P zur IN appliziert. In der Gr A wurden der RR und die HF an drei Meßzeitpunkten (MZP) gemessen: MZP 1=vor P-Gabe; MZP 2=nach P-Gabe; MZP 3=nach IN, in der Gr B an den MZP 1 und 3. In der Gr B wurde außerdem die IZ in Sekunden (s) gemessen (t1=Zeit nach P-Gabe bis Beginn des IN-Vorgangs; t2=Zeit bis Ende IN; t3=t2–t1). Festgehalten wurden in beiden Gr ebenfalls die IB (Note 1=sehr gute IB; 2=gute IB; 3=schlechte IB; 4=IN unmöglich). Ergebnisse: Die Mittelwerte (MW) des RRs/RRm/RRd/HF veränderten sich in der Gr A am MZP 2 um –11,20*/–9,18*/–8,58*/ –3,52 mm Hg/bpm und am MZP 3 um –2,74/–2,26/–2,04/+5,46 mm Hg/bpm gegenüber dem MZP 1 (*=signifikanter Unterschied). In der Gr B veränderten sich die MW von RRs/RRm/RRd/HF am MZP 3 um –0,89/ +0,50/–0,80/+4,20* mm Hg/bpm gegenüber MZP 1. Die Zeit t1 betrug im MW (±SD) 10,88±3,52 s, die Zeit t2 26,22±6,12 s. T3 betrug damit im MW 15,78±6,28 s. Für die IB konnten in beiden Gr immer die Noten 1 bzw. 2 vergeben werden (Gr A und B [n gesamt=100]: Note 1=95x=95%; Note 2=5x=5%). Schlußfolgerung: Die RR- und HF-Veränderungen blieben im Referenzbereich, die ausschließlich sehr guten und guten IB sowie die ultrakurzen „Anschlagzeiten” und IZ belegen die sehr guten Eigenschaften des P für die IN im Säuglingsalter.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Der Anaesthesist 46 (1997), S. 850-855 
    ISSN: 1432-055X
    Keywords: Schlüsselwörter Prämedikation ; Midazolam ; Adrenalin ; Kortisol ; Kinder ; Key words Premedication ; Midazolam ; Epinephrine ; Cortisol ; Child
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Abstract Anxiolysis with drugs and psychoprophylaxis are both recognised methods of preoperative preparation. The beneficial effects of anxiolytics, however, appear to be difficult to prove. In this study a comparison was made of heart rate (HR), blood pressure (BP), and norepinephrine, epinephrine, and cortisol levels. In group I 19 children recieved only psychological treatment, while in group II 21 children received 0.2 mg/kg midazolam orally. Measuring points were directly before medication, 30 min afterward, and at induction of anaesthesia. During the observation period the patients (5–10 years old) remained calm. At the beginning of the study the parameters of all patients were within a normal range; 30 min after premedication the HR and BP were significantly higher in group I than in group II. In contrast to group I, epinephrine levels in group II were lower at the beginning of anaesthesia than before premedication. In both groups, norepinephrine levels were the same at induction of anaesthesia as before premedication. Cortisol decreased only in patients who received midazolam. HR, BP, as well as humoral stress parameters indicate that midazolam in a dose of 0.2 mg/kg orally is sufficient to reduce preoperative stress in children.
    Notes: Zusammenfassung Sowohl Anxiolyse mit Medikamenten als auch psychische Führung sind anerkannte Methoden der präoperativen Vorbereitung. Ein Vorteil von Anxiolytika ist aber für Kinder schwer zu beweisen. Material und Methoden. In dieser Untersuchung wurden Herzfrequenz, Blutdruck, Noradrenalin, Adrenalin und Kortisol als Streßindikatoren zum Vergleich gewählt. Wir betreuten 19 Kinder in Gruppe I psychisch, 21 Kinder der Gruppe II erhielten Midazolam oral (0,2 mg/kg) zur Prämedikation. Die Meßpunkte lagen unmittelbar vor und 30 min nach Prämedikation sowie zu Narkosebeginn. Ergebnisse. Im Beobachtungszeitraum wirkten alle Kinder unauffällig mit vergleichbaren Ausgangswerten. 30 min nach psychischer Führung hatte diese Gruppe signifikant höhere Herzfrequenzen als die Vergleichsgruppe. Analog dazu zeigte sich der Blutdruck. Im Gegensatz zu Gruppe I blieben die Adrenalinspiegel in Gruppe II auch zur Narkoseeinleitung unter den Ausgangswerten. Die Noradrenalinspiegel glichen zu Narkosebeginn in beiden Gruppen der Ausgangssituation. Nur in der Midazolamgruppe blieb Kortisol bis zum Narkosebeginn unter den Ausgangswerten. Schlußfolgerungen. Herzfrequenz und Blutdruck sowie humorale Streßparameter zeigen, daß Midazolam in einer Dosierung von 0,2 mg/kg zu einer Streßreduktion bei Kindern führt.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1420-9071
    Keywords: Angiotensin-converting enzyme (ACE) ; new ACE inhibitory compounds ; perimidines ; chinazolinones ; amidinohydrazones ; structure-activity-relations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ACE inhibitory activity of some perimidines, chinazolinones and amidinohydrazones is described. Relations were found between the chemical structure and the inhibitory activity on the ACE.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 237-244 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of 8H-1,2,4-Triazolo[4,3-a]perimidinesReaction of 2-hydrazinoperimidine (3) with carboxylic acids or its orthoesters leads to 8H-1,2,4-triazolo[4,3-a]perimidines (5a-h). 3 and aldehydes yield the aldehydehydrazones (6b,c,d) which are converted in 5 by air oxidation. The structures of the new compounds were determined by means of i.r., u.v., 1H-n.m.r. and mass spectroscopy.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 329 (1987), S. 332-336 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Perimidines. III. Reaction of Acylactivated Geminal Dichlorovinyl Compounds with 1,8-Diaminonaphthalene
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 906-910 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Perimidines. II. The Reaction of 1,8-Diaminonaphthalene with γ- and δ-Lactones
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Oxidative Coupling of CH-acid Compounds with p-Phenylene Diamines. III. Reactivity of 4-Substituted 3-Methyl-1-phenyl-pyrazolin-5-ones with N,N-Diethyl-quinone-(1,4)-diimineSubstitution products 2-28 of 3-methyl-1-phenyl-pyrazolin-5-one 1, with a wide variety of substituents in the 4-position, were synthesized. Most of these compounds react with N,N-diethyl-quinone-(1,4)-diimine by elimination of the substituent giving the same azomethine dye as that formed by oxidative coupling of the 4-unsubstituted compound. A study of the influence of side reactions by measurement of dye yields has been undertaken.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
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