Semiclassical Mechanics of Rotons

The elementary excitations in superfluid liquid He-4 named rotons have an unusual dispersion curve. The energy is an approximately quadratic function of (p-p_0), the difference between the magnitude of the momentum p and a characteristic value p_0. As a result, while for p>p_0 a roton has its (group) velocity parallel to its momentum, when p<p_0 the velocity and momentum are antiparallel. When p=p_0, the roton has non-zero momentum but zero velocity. These kinematic properties lead to unusual trajectories when rotons scatter or experience external forces. This paper examines this behavior in the classical (ray optics) limit, where the roton wavelength is small compared with all other dimensions. Several experiments illustrate these effects. The examples are interesting in themselves, and also offer unconventional pedagogical possibilities.Comment: 21 pp, 7 figures, submitted to Contemporary Physic

Effects of arcing due to spacecraft charging on spacecraft survival

A quantitative assessment of the hazard associated with spacecraft charging and arcing on spacecraft systems is presented. A literature survey on arc discharge thresholds and characteristics was done and gaps in the data and requirements for additional experiments were identified. Calculations of coupling of arc discharges into typical spacecraft systems were made and the susceptibility of typical spacecraft to disruption by arc discharges was investigated. Design guidelines and recommended practices to reduce or eliminate the threat of malfunction and failures due to spacecraft charging/arcing were summarized

Injection and mobility of potassium ions in liquid helium

Potassium ions from a hot tungsten wire are injected into He II; their mobility is found to be two to three percent lower than that of `normal' positive ions.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32758/1/0000127.pd

Influence of Bos Taurus and Bos Indicus Breedtype on Production of Cortisol

Last updated: 6/12/200

Extended Hauser-Feshbach Method for Statistical Binary-Decay of Light-Mass Systems

An Extended Hauser-Feshbach Method (EHFM) is developed for light heavy-ion fusion reactions in order to provide a detailed analysis of all the possible decay channels by including explicitly the fusion-fission phase-space in the description of the cascade chain. The mass-asymmetric fission component is considered as a complex-fragment binary-decay which can be treated in the same way as the light-particle evaporation from the compound nucleus in statistical-model calculations. The method of the phase-space integrations for the binary-decay is an extension of the usual Hauser-Feshbach formalism to be applied to the mass-symmetric fission part. The EHFM calculations include ground-state binding energies and discrete levels in the low excitation-energy regions which are essential for an accurate evaluation of the phase-space integrations of the complex-fragment emission (fission). In the present calculations, EHFM is applied to the first-chance binary-decay by assuming that the second-chance fission decay is negligible. In a similar manner to the description of the fusion-evaporation process, the usual cascade calculation of light-particle emission from the highly excited complex fragments is applied. This complete calculation is then defined as EHFM+CASCADE. Calculated quantities such as charge-, mass- and kinetic-energy distributions are compared with inclusive and/or exclusive data for the $^{32}$S+$^{24}$Mg and $^{35}$Cl+$^{12}$C reactions which have been selected as typical examples. Finally, the missing charge distributions extracted from exclusive measurements are also successfully compared with the EHFM+CASCADE predictions.Comment: 34 pages, 6 Figures available upon request, Phys. Rev. C (to be published

Petroleomics by ion mobility mass spectrometry: resolution and characterization of contaminants and additives in crude oils and petrofuels

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Ion mobility-mass spectrometry (IM-MS), performed with exceptional resolution and sensitivity in a new uniform-field drift tube ion mobility quadrupole time-of-flight (IM-QTOF) instrument, is shown to provide a useful tool for resolving and characterizing crude oils and their contaminants, as well as petrofuels and their additives. Whereas direct analysis of a crude oil sample contaminated with demulsifiers by the classical ESI(+/-)-FTICR-MS petroleomic approach was unsatisfactory since it responds only with abundance and m/z, and ionization is impaired due to suppression of polar compounds of crude oil by additives likely used in petroleum industry, IM-MS enables mobility separation of ions, particularly of double bond equivalent (DBE) series for a giving CnX class providing separated spectra which are typical obtained either for the crude oil or the contaminants, even suffering of ion suppression or low ionization efficiency. The combination of improved IM resolution and high mass resolving power (40,000@400) of the QTOF instrument provides useful information on class (N, NO, NS, etc.), carbon number (C-n), and unsaturation (DBE) levels for crude oils, allowing one to infer geochemical properties from DBE trends that can be compared with IM-MS data. As demonstrated by results of gasoline samples with additives, the IM-MS system also allows efficient separation and characterization of additives and contaminants in petrofuels.Ion mobility-mass spectrometry (IM-MS), performed with exceptional resolution and sensitivity in a new uniform-field drift tube ion mobility quadrupole time-of-flight (IM-QTOF) instrument, is shown to provide a useful tool for resolving and characterizing71144504463FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAPESP [2013/19161-4]2013/19161-4sem informaçãosem informaçãoWe would like to thank the Fundação de Amparo a Pesquisa do Estado de São Paulo (FAPESP) for the scholarship awarded to J.M.S. (process number 2013/19161-4), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) and Conselho Nacional de Des

Beneficial effects of word final stress in segmenting a new language: evidence from ERPs

Background: How do listeners manage to recognize words in an unfamiliar language? The physical continuity of the signal, in which real silent pauses between words are lacking, makes it a difficult task. However, there are multiple cues that can be exploited to localize word boundaries and to segment the acoustic signal. In the present study, word-stress was manipulated with statistical information and placed in different syllables within trisyllabic nonsense words to explore the result of the combination of the cues in an online word segmentation task. Results: The behavioral results showed that words were segmented better when stress was placed on the final syllables than when it was placed on the middle or first syllable. The electrophysiological results showed an increase in the amplitude of the P2 component, which seemed to be sensitive to word-stress and its location within words. Conclusion: The results demonstrated that listeners can integrate specific prosodic and distributional cues when segmenting speech. An ERP component related to word-stress cues was identified: stressed syllables elicited larger amplitudes in the P2 component than unstressed ones

The breast feeding mother and xenon anaesthesia: four case reports. Breast feeding and xenon anaesthesia

<p>Abstract</p> <p>Background</p> <p>Four nursing mothers consented to anaesthesia for urgent surgery only on condition that their ability to breast feed would not be impaired.</p> <p>Methods</p> <p>Following induction of general anaesthesia with propofol and remifentanil, 65-69% xenon supplemented with remifentanil was used as an inhalational anaesthetic for maintenance.</p> <p>Results</p> <p>After finishing surgery the women could be extubated between 2:52 and 7:22 minutes. The women were fully alert just minutes after extubation and spent about 45 minutes in the recovery room before discharge to a regular ward. They resumed regular breast feeding some time later. The propofol concentration in the blood was measured after 0, 30, 90, and 300 minutes and in the milk after 90 and 300 minutes. Just 90 minutes after extubation, the concentration of propofol in the milk was limited (> 3 mg/l) so that pharmacological effects on the babies were excluded after oral intake. Also, no traces of xenon gas were found in the maternal milk at any time. After propofol induction and maintenance of anaesthesia with xenon in combination with a water-soluble short-acting drug like remifentanil, the concentration of propofol in maternal milk is low (> 3 mg/l 90 min after anesthesia) and harmless after oral intake.</p> <p>Conclusions</p> <p>These results, as well as the rapid elimination and absence of metabolism of xenon, are of great interest to nursing mothers. General anaesthesia with propofol for induction only, combined with remifentanil and xenon for maintenance, has not yet been described in breast feeding mothers.</p