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Scénarios de pénétration des composés oxygénés en Europe de l'Ouest Scenarios for the Penetration of Oxygenated Compounds in Western Europe
Beaufils J. P.,Meyer C.
Oil & Gas Science and Technology , 2006, DOI: 10.2516/ogst:1987014
Abstract: Scénarios de pénétration des composés oxygénés en Europe de l'Ouest Différents scénarios de progression de la consommation de carburants sans plomb dans l'ensemble des pays européens ont été examinés. Les besoins en composés oxygénés en ont été déduits. Les résultats montrent que les disponibilités additionnées des composés oxygénés (MTBE, M3T2, TBA) permettront de satisfaire la demande maximale potentielle au début des années 1990, mais n'autoriseront ensuite qu'une addition limitée de ces composés; la concentration de chacun d'entre eux restera très inférieure aux limites autorisées. Les décisions de construction de nouvelles unités seraient à prendre avant 1995. Different scenarios are examined for the penetration of unleaded gasoline in the European countries. The requirements of oxygenated compounds have been deduced from these scenarios. The results show that the supply of oxygenated compounds (MTBE, M3T2, TBA) will be able to meet the maximum potential demand in the early 1990s. Subsequently, however, only a limited amount of such compounds can be added. The concentration of each compound will remain considerably lower than the authorized limits. Decisions to build new plants will have to be made before 1995.
THE DEPLOYMENT OF SOVIET CHEMICAL FORCES IN AFGHANISTAN AND SOUTHEAST ASIA
C.M. Meyer,P. Theron
Scientia Militaria : South African Journal of Military Studies , 2012, DOI: 10.5787/14-1-527
Abstract: 'And let there be no doubt: if hostilities should break out, the Soviet Army would use chemical weapons against its opponents.' Col Oleg Penkovsky Recently chemical warfare has become a most distinct feature of military technique. This can be said after it has been established that the Soviet Union used chemical agents in South-East Asia and Afghanistan. The first reports dealt with some unexplained deaths among the Hmong people of Laos and shortly afterwards came the discovery of tiny yellow deposits of pollen containing lethal toxins. In the wake of this discovery the United States alleged that Soviet-backed forces were using 'yellow rain' toxins in violation of treaties banning biological and chemical weapons. The Soviets' strong denial met with skepticism in Western circles, and did nothing to quell a raging debate over the precise interpretation of toxins found in Kampuchea and Afghanistan. In this overview the facts and reports pertaining to the topic under discussion are correlated and examined..
Katheterablation ventrikul rer Tachykardien
Meyer C,Martinek M,Pürerfellner H
Journal für Kardiologie , 2011,
Abstract: In der Behandlung idiopathischer ventrikul rer Tachykardien (VT) hat sich die Katheterablation in den vergangenen Jahren zunehmend als eine Therapie der Wahl etabliert. Zus tzlich konnte in den vergangenen Jahren die Therapie von VT auf dem Boden struktureller Herzerkrankungen deutlich verbessert werden. Mittels neuer Mapping- und Ablationsverfahren k nnen heute auch VT, bei denen eine fehlende Induzierbarkeit, sowie eine schwerwiegende h modynamische Beeintr chtigung betroffener Patienten besteht, zunehmend erfolgreich behandelt werden. Grunds tzlich sollte die Katheterablation vor diesem Hintergrund relativ früh in Erw gung gezogen werden, bevor es bei Patienten mit struktureller Herzerkrankung zu wiederholten Schockabgaben implantierbarer Cardioverter- Defibrillatoren und resultierenden Traumatisierungen gekommen ist. Die vorliegende übersicht fasst unter Berücksichtigung differentialdiagnostischer Aspekte die M glichkeiten der Katheterablation in der Therapie von ventrikul ren Tachyarrhythmien zusammen.
The Origin of Present Day Cosmic Rays: Fresh SN Ejecta or Interstellar Medium Material ? I Cosmic Ray Composition and SN Nucleosynthesis. A Conflict with the Early Galactic Evolution of Be ?
J. P. Meyer,D. C. Ellison
Physics , 1999,
Abstract: The composition of present day cosmic rays (CRs) is inconsistent with a significant acceleration of SN ejecta material (even with a preferential acceleration of ejecta grain material). Current CRs must result mainly from the acceleration of ISM ("solar mix") and circumstellar (22Ne- and 12C-rich WR wind) gas and grain material. The CR source composition, indeed, shows no anomaly related to SN nucleosynthesis: (i) The CR source FeNi/MgSiCa ratios have precisely solar mix values, while FeNi are mainly synthesized in SN Ia's, and MgSiCa in SN II's. If CR's originate in SN ejecta, this requires tight conditions on the acceleration efficiencies of the various SN Ia's and SN II's. (ii) The non-deficiency of the main-s-process elements, not made in any SN, relative to all elements made in SNae. (iii) All CR source isotope ratios are consistent with solar mix (except for the 22Ne and 12C excesses, WR wind). (iv) The absence of 59Ni in CRs implies that the time delay between the SN nucleosynthesis and their acceleration is > 10^5 yr. (v) The physics of SNR's and of CR shock acceleration implies that the acceleration of interior ejecta material is comparatively insignificant (Ellison & Meyer, this volume). Predominant acceleration of current CRs out of superbubble material also seems implausible. These conclusions regarding current CRs do not necessarily conflict with the linear evolution of Be/H in the early Galaxy. With the near absence of heavy elements in the early Galactic ISM, indeed, the acceleration of even a minute amount of freshly processed material must have then played a dominant role for the generation of Be from C and O. The "Be indicator" is blind to a possibly dominant early Galactic CR component originating in the ISM then composed of virtually pure H and He.
The Origin of Present Day Cosmic Rays: Fresh SN Ejecta or Interstellar Medium Material ? II Physics of the SNR shock wave acceleration
D. C. Ellison,J. P. Meyer
Physics , 1999,
Abstract: Assuming that refractory elements in cosmic rays originate in dust grains, we examine the viability of cosmic ray origin models wherein the bulk of present day cosmic rays are accelerated out of fresh supernova ejecta material before it mixes with the average interstellar medium (ISM). We conclude that the fresh ejecta scenarios that have been proposed thus far have serious flaws, and are unable to account for known properties of present day cosmic rays. These flaws include: (1) the small fraction of ejecta to ISM mass processed by the forward supernova remnant (SNR) shock; (2) the difficulty fresh ejecta grains have in reaching the forward shock in isolated SNRs, and the small expected sputtering yield, especially ahead of the shock, even if grains do reach the forward shock; (3) the implausibility that fresh ejecta material can dominate cosmic ray production in diffuse superbubbles; and (4) the lack of a connection in fresh ejecta models between the production of cosmic ray refractory and volatile elements. We conclude that the near linear increase in Be abundance with metallicity observed in old, halo stars cannot imply that a significant fraction of the cosmic rays seen today come from fresh supernova ejecta. This conclusion is supported by the analysis of the present day cosmic ray composition, as shown in Meyer & Ellison, this volume.
Interpreting the Cosmic Ray Composition
L. O'C Drury,J. P. Meyer,D. C Ellison
Physics , 1999, DOI: 10.1016/S0375-9474(99)00728-9
Abstract: Detailed composition measurements can be a very powerful means of tracing origins, a fact used regularly by forensic scientists and art historians. One of the main motivating factors for making detailed observations of cosmic rays was always the hope that a unique compositional signature could be found which pointed unambiguously to a particular source. This has proven much harder than expected, but we have now reached a point where it appears possible to begin to decipher the information contained in the compositional data; the key, we have discovered, is to read the data not in isolation, but in the context provided by our general astronomical knowledge and by recent developments in shock acceleration theory (Meyer, Drury and Ellison, 1997, 1998; Ellison, Drury and Meyer, 1997). In our view (not, it is only fair to warn the reader, yet universally accepted) the data show clearly that the Galactic cosmic ray particles originate predominantly from the gas and dust of the general interstellar medium.
Enhancing temporal resolution in pump-probe experiments with noisy pulses
Meyer K.,Ott C.,Raith P.,Kaldun A.
EPJ Web of Conferences , 2013, DOI: 10.1051/epjconf/20134102001
Abstract: We show how light fields that vary statistically in time (e.g. at FELs) enable higher temporal resolution than expected from their average pulse duration. An experimental example in deuterium molecules confirmed this general effect.
Sympathetic hyperactivity influences chemosensor function in patients with end-stage renal disease
Meyer C,Schueller P,Balzer J,Lauer T
European Journal of Medical Research , 2009, DOI: 10.1186/2047-783x-14-s4-151
Abstract: Background Autonomic neuropathy is common in patients suffering from end-stage renal disease (ESRD). This may in part explain the high cardiovascular mortality in these patients. Chemosensory function is involved in autonomic cardiovascular control and is mechanistically linked to the sympathetic tone. Objective The aim of the present study was to assess whether sympathetic hyperactivity contributes to an altered chemosensory function in ESRD. Materials and methods In a randomized, double-masked, placebo controlled crossover design we studied the impact of chemosensory deactivation on heart rate, blood pressure and oxygen saturation in 10 ESRD patients and 10 age and gender matched controls. The difference in the R-R intervals divided by the difference in the oxygen pressures before and after deactivation of the chemoreceptors by 5-min inhalation of 7 L oxygen was calculated as the hyperoxic chemoreflex sensitivity (CHRS). Placebo consisted of breathing room air. Baseline sympathetic activity was characterized by plasma catecholamine levels and 24-h time-domain heart rate variability (HRV) parameters. Results Plasma norepinephrine levels were increased (1.6 ± 0.4 vs. 5.8 ± 0.6; P < 0.05) while the SDNN (standard deviation of all normal R-R intervals: 126.4 ± 19 vs. 100.2 ± 12 ms), the RMSSD (square root of the mean of the squared differences between adjacent normal R-R intervals: 27.1 ± 8 vs. 15.7 ± 2 ms), and the 24-h triangular index (33.6 ± 4 vs. 25.7 ± 3; each P < 0.05) were decreased in ESRD patients as compared to controls. CHRS was impaired in ESRD patients (2.9 ± 0.9 ms/mmHg, P < 0.05) as compared to controls (7.9 ± 1.4 ms/mmHg). On multiple regression analysis 24 h-Triangular index, RMSSD, and plasma norepinephrine levels were independent predictors of an impaired hyperoxic CHRS. Conclusion Sympathetic hyperactivity influences chemosensory function in ESRD resulting in an impaired hyperoxic CHRS.
Effectiveness of Annealing Blocking Primers versus Restriction Enzymes for Characterization of Generalist Diets: Unexpected Prey Revealed in the Gut Contents of Two Coral Reef Fish Species
Matthieu Leray, Natalia Agudelo, Suzanne C. Mills, Christopher P. Meyer
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0058076
Abstract: Characterization of predator-prey interactions is challenging as researchers have to rely on indirect methods that can be costly, biased and too imprecise to elucidate the complexity of food webs. DNA amplification and sequencing techniques of gut and fecal contents are promising approaches, but their success largely depends on the ability to amplify the taxonomic array of prey consumed and then match prey amplicons with reference sequences. When little a priori information on diet is available or a generalist predator is targeted, versatile primer sets (also referred to as universal or general primers) as opposed to group- or species-specific primer sets are the most powerful to unveil the full range of prey consumed. However, versatile primers are likely to preferentially amplify the predominant, less degraded predator DNA if no manipulation is performed to exclude this confounding DNA template. In this study we compare two approaches that eliminate the confounding predator template: restriction digestion and the use of annealing blocking primers. First, we use a preliminary DNA barcode library provided by the Moorea BIOCODE project to 1) evaluate the cutting frequency of commercially available restriction enzymes and 2) design predator specific annealing blocking primers. We then compare the performance of the two predator removal strategies for the detection of prey templates using two versatile primer sets from the gut contents of two generalist coral reef fish species sampled in Moorea. Our study demonstrates that blocking primers should be preferentially used over restriction digestion for predator DNA removal as they recover greater prey diversity. We also emphasize that a combination of versatile primers may be required to best represent the breadth of a generalist's diet.
Evidence of natural isotopic distribution from single-molecule SERS
P. G. Etchegoin,E. C. Le Ru,M. Meyer
Physics , 2008,
Abstract: We report on the observation of the natural isotopic spread of carbon from single-molecule Surface Enhanced Raman Spectroscopy (SM-SERS). By choosing a dye molecule with a very localized Raman active vibration in a cyano bond (C$\equiv$N triple bond), we observe (in a SERS colloidal liquid) a small fraction of SM-SERS events where the frequency of the cyano mode is softened and in agreement with the effect of substituting $^{12}$C by the next most abundant $^{13}$C isotope. This example adds another demonstration of single molecule sensitivity in SERS through isotopic editing which is done, in this case, not by artificial isotopic editing but rather by nature itself. It also highlights SERS as a unique spectroscopic tool, capable of detecting an isotopic change in one atom of a single molecule.
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