Solar Modulation of the Galactic Helium Spectrum Above 30 Mev Per Nucleon

Time measurements of differential energy spectra and flux of primary helium nuclei by use of charged particle telescope

Acceleration of particles in the earth's shock transition region and beyond

Acceleration of particles in earth shock transition region and beyon

Embedded Eigenvalues and the Nonlinear Schrodinger Equation

A common challenge to proving asymptotic stability of solitary waves is understanding the spectrum of the operator associated with the linearized flow. The existence of eigenvalues can inhibit the dispersive estimates key to proving stability. Following the work of Marzuola & Simpson, we prove the absence of embedded eigenvalues for a collection of nonlinear Schrodinger equations, including some one and three dimensional supercritical equations, and the three dimensional cubic-quintic equation. Our results also rule out nonzero eigenvalues within the spectral gap and, in 3D, endpoint resonances. The proof is computer assisted as it depends on the sign of certain inner products which do not readily admit analytic representations. Our source code is available for verification at http://www.math.toronto.edu/simpson/files/spec_prop_asad_simpson_code.zip.Comment: 29 pages, 27 figures: fixed a typo in an equation from the previous version, and added two equations to clarif

Diffuse gamma radiation

An examination of the intensity, energy spectrum, and spatial distribution of the diffuse gamma-radiation observed by SAS-2 satellite away from the galactic plane in the energy range above 35 MeV has shown that it consists of two components. One component is generally correlated with galactic latitudes, the atomic hydrogen column density was deduced from 21 cm measurements, and the continuum radio emission, believed to be synchrotron emission. It has an energy spectrum similar to that in the plane and joins smoothly to the intense radiation from the plane. It is therefore presumed to be of galactic origin. The other component is apparently isotropic, at least on a coarse scale, and has a steep energy spectrum. No evidence is found for a cosmic ray halo surrounding the galaxy in the shape of a sphere or oblate spheroid with galactic dimensions. Constraints for a halo model with significantly larger dimensions are set on the basis of an upper limit to the gamma-ray anisotropy

Designing a programming-based approach for modelling scientific phenomena

We describe an iteratively designed sequence of activities involving the modelling of 1- dimensional collisions between moving objects based on programming in ToonTalk. Students aged 13-14 in two settings (London and Cyprus) investigated a number of collision situations, classified into six classes based on the relative velocities and masses of the colliding objects. We describe iterations of the system in which students engaged in a repeating cycle of activity for each collision class: prediction of object behaviour from given collision conditions, observation of a relevant video clip, building a model to represent the phenomena, testing, validating and refining their model, and publishing it ? together with comments ? on our web-based collaboration system, WebReports. Students were encouraged to consider the limitations of their current model, with the aim that they would eventually appreciate the benefit of constructing a general model that would work for all collision classes, rather than a different model for each class. We describe how our intention to engage students with the underlying concepts of conservation, closed systems and system states was instantiated in the activity design, and how the modelling activities afforded an alternative representational framework to traditional algebraic description

Aroma composition of Chardonnay wine

The headspace aroma volatiles of Chardonnay wines from 6 consecutive· vintages were analysed by capillary gas chromatography and gas chromatography-mass spectrometry, some 150 compounds were identified. The contribution to aroma of the components of the headspace collection was determined by sniffing the column effluent following gas chromatographic separation. The major fermentation alcohols and esters, acetic acid and damascenone were important aroma compounds of the Chardonnay wines.Die Aromazusammensetzung von Chardonnay-WeinDie Aromastoffe im Dampfraum von Chardonnay-Weinen aus 6 aufeinanderfolgenden Jahrgängen wurden mittels Kapillar-Gaschromatographie und Gaschromatographie-Massenspektrometrie analysiert; hierbei wurden ungefähr 150 Verbindungen identifiziert. Ihre Beteiligung am Aroma des im Dampfraum enthaltenen Substanzgemisches wurde durch „Erschnüffeln" der gaschromatographisch aufgetrennten Komponenten bestimmt. Die wichtigsten Gärungsalkohole und -ester, Essigsäure sowie Damascenon stellen wesentliche Aromastoffe der Chardonnay-Weine dar

Aroma composition of aged Riesling wine

The aroma compositions of 1967, 1969, 1971, 1973 and 1975 Riesling wines made under similar conditions were analysed by headspace GC and GC-MS. Over 140 compounds were identified, many of which were derivable from carbohydrate and carotenoid degradations and terpenoid rearrangements. The 2 isomeric vitispiranes and 1,1,6-trimethyl-1,2-dihydronaphthalene (TDN) were produced in 9 varietal grape juices with heating: the quantities formed were influenced by grape variety and pH. Riesling juice gave the highest concentrations of TDN, which indicated that wine from this grape variety has the most potential to produce aroma-significant quantities of TDN during long-term cellar storage.Die Aromazusammensetzung von gealtertem RieslingweinDie Aromazusammensetzung von Rieslingweinen der Jahrgänge 1967, 1969, 1971, 1973 und 1975, die unter ähnlichen Bedingungen hergestellt worden waren, wurde mit Hilfe der Dampfraum-Gaschromatographie bzw. auf gaschromatographisch-massenspektrometrischero Wege analysiert. Es wurden über 140 Verbindungen identifiziert, von denen sich viele aus abgebauten Kohlenhydraten und Carotinoiden oder aus umgewandelten Terpenoiden herleiten ließen. Bei Wärmebehandlung des Traubensaftes von 9 Rebsorten wurden die beiden isomeren Vitispirane und l,l,6-Trimethyl-1,2-dihydronaphthalin (TDN) gebildet; die entstandenen Mengen waren von Rebsorte und pH abhängig. Rieslingmost erbrachte die höchsten TDN-Konzentrationen. Dies weist darauf hin, daß im Wein dieser Rebsorte bei langer Kellerlagerung am sichersten aromawirksame Mengen von TDN zu erwarten sind

Anisotropic magnetoresistance of bulk carbon nanotube sheets

We have measured the magnetoresistance of stretched sheets of carbon nanotubes in temperatures ranging from 2 K to 300 K and in magnetic fields up to 9 T, oriented either perpendicular or parallel to the plane of the sheets. The samples have been partially aligned by post-fabrication stretching, such that the direction of stretching was either parallel or perpendicular to the direction of applied electric current. We have observed large differences between the magnetoresistance measured under the two field orientations, most pronounced at the lowest temperatures, highest fields, and for the laterally-aligned sample. Treatment of the sheets with nitric acid affects this anisotropy. We analyzed the results within the theoretical framework of weak and strong localization and concluded that the anisotropy bears the mark of a more unusual phenomenon, possibly magnetically-induced mechanical strain.Comment: 34 pages, 10 figure