Cyclic metric Lie groups

Cyclic metric Lie groups are Lie groups equipped with a left-invariant metric which is in some way far from being biinvariant, in a sense made explicit in terms of Tricerri and Vanhecke's homogeneous structures. The semisimple and solvable cases are studied. We extend to the general case, Kowalski-Tricerri's and Bieszk's classifications of connected and simply-connected unimodular cyclic metric Lie groups for dimensions less than or equal to five

The English-Language Proficiency of Recent Immigrants in the U.S. During the Early 1900s

Using U.S. decennial census data, we find that in 1920, immigrants (particularly those from Southern and Eastern Europe) were more likely to speak the English language within three years of migrating than their counterparts had been in either 1900 or 1910. Our results suggest that the foreign-born reacted to socioeconomic and political events by learning English before or shortly after migrating to the U.S. This study not only provides previously unknown information about immigrants’ English fluency in the early twentieth century, but it also offers empirical insight into the assimilation pressures that certain immigrant groups experienced at the time.

Ground Level Enhancement in the 2014 January 6 Solar Energetic Particle Event

We present a study of the 2014 January 6 solar energetic particle (SEP) event, which produced a small ground level enhancement (GLE), making it the second GLE of this unusual solar cycle 24. This event was primarily observed by the South Pole neutron monitors (increase of ~2.5%) whereas a few other neutron monitors recorded smaller increases. The associated coronal mass ejection (CME) originated behind the western limb and had the speed of 1960 km/s. The height of the CME at the start of the associated metric type II radio burst, which indicates the formation of a strong shock, was measured to be 1.61 Rs using a direct image from STEREO-A/EUVI. The CME height at the time of GLE particle release (determined using the South Pole neutron monitor data) was directly measured as 2.96 Rs, from the STEREO-A/COR1 white-light observations. These CME heights are consistent with those obtained for the GLE71, the only other GLE of the current cycle as well as cycle-23 GLEs derived using back-extrapolation. GLE72 is of special interest because it is one of the only two GLEs of cycle 24, one of the two behind-the-limb GLEs and one of the two smallest GLEs of cycles 23 and 24

Spin-Orbit Relaxation of Cesium 7 \u3csup\u3e2\u3c/sup\u3eD in Mixtures of Helium and Argon

Pulsed excitation on the two-photon Cs 62S1/2 -\u3e 72D3/2,5/2 transition results in time-resolved fluorescence at 697 and 672 nm. The rates for fine-structure mixing between the 72D3/2,5/2 states have been measured for helium and argon rare-gas collision partners. The mixing rates are very fast, 1.26±0.05×10−9 cm3/atom s for He and 1.52±0.05×10−10 cm3/atom s for Ar, driven by the small energy splitting and large radial distribution for the valence electron. The quenching rates are considerably slower, 6.84±0.09×10−11 and 2.65±0.04×10−11 cm3/atom s for He and Ar, respectively. The current results are placed in context with similar rates for other alkali-metal–rare-gas collision pairs using adiabaticity arguments

Coexistence of Self-Organized Criticality and Intermittent Turbulence in the Solar Corona

An extended data set of extreme ultraviolet images of the solar corona provided by the SOHO spacecraft are analyzed using statistical methods common to studies of self-organized criticality (SOC) and intermittent turbulence (IT). The data exhibits simultaneous hallmarks of both regimes, namely power law avalanche statistics as well as multiscaling of structure functions for spatial activity. This implies that both SOC and IT may be manifestations of a single complex dynamical process entangling avalanches of magnetic energy dissipation with turbulent particle flows.Comment: 4 pages, 4 figure

Modeling Transverse Cracking in Laminates With a Single Layer of Elements Per Ply

The objective of the present paper is to investigate the ability of mesolevel X-FEM models with a single layer of elements per ply to capture accurately all aspects of matrix cracking. In particular, we examine whether the model can predict the insitu ply thickness effect on crack initiation and propagation, the crack density as a function of strain, the strain for crack saturation, and the interaction between delamination and transverse cracks. Results reveal that the simplified model does not capture correctly the shear-lag relaxation of the stress field on either side of a crack, which leads to an overprediction of the crack density. It is also shown, however, that after onset of delamination many of the inserted matrix cracks close again, and that the density of open cracks becomes similar to the density predicted by the detailed model. The degree to which the spurious cracks affect the global response is quantified and the reliability of the mesolevel approach with a single layer of elements per ply is discussed

Emission lines of Fe X in active region spectra obtained with the Solar Extreme-ultraviolet Research Telescope and Spectrograph

Fully relativistic calculations of radiative rates and electron impact excitation cross sections for Fe X are used to derive theoretical emission-line ratios involving transitions in the 174-366 A wavelength range. A comparison of these with solar active region observations obtained during the 1989 and 1995 flights of the Solar Extreme-ultraviolet Research Telescope and Spectrograph (SERTS) reveals generally very good agreement between theory and experiment. Several Fe X emission features are detected for the first time in SERTS spectra, while the transition at 195.32 A is identified for the first time (to our knowledge) in an astronomical source. The most useful Fe X electron density diagnostic line ratios are assessed to be 175.27/174.53 and 175.27/177.24, which both involve lines close in wavelength and free from blends, vary by factors of 13 between Ne = 1E8 and 1E13 cm-3, and yet show little temperature sensitivity. Should these lines not be available, then the 257.25/345.74 ratio may be employed to determine Ne, although this requires an accurate evaluation of the instrument intensity calibration over a relatively large wavelength range. However, if the weak 324.73 A line of Fe X is reliably detected, the use of 324.73/345.74 or 257.25/324.73 is recommended over 257.25/345.74.Comment: 11 pages, 10 figures, MNRAS in pres

Improving the undergraduate science experience through an evidence-based framework for design, implementation and evaluation of flipped learning

© ASCILITE 2017 - Conference Proceedings - 34th International Conference of Innovation, Practice and Research in the Use of Educational Technologies in Tertiary Education.All right reserved. Flipped Learning (FL) is a student-centred pedagogical approach where new content is introduced prior to class which permits more time during class for active learning. Despite the growing body of evidence of the effectiveness of FL, many educators are reluctant to adopt this approach to teaching or are unsure of how to implement FL in their classes. Many students are uncertain of how to adapt their approaches to learning to a FL curriculum. In response to these challenges and calls for a robust framework to guide the design and implementation of FL, we developed the Flipped Teacher and Flipped Learner (FTFL) Framework based on the pedagogical literature. This paper reports on the use of our FTFL framework in the redesign of a large first year science subject from a traditional delivery to a FL delivery. We evaluated the efficacy of the redesign using a mixed methods approach with data on students' interactions with FL activities, and student and educator experiences. Findings from two iterations of the redesign indicate successful implementation of FL through high student engagement with online and class materials, and positive feedback from students and academics. Using the FTFL framework to guide the design and integration of FL, with an emphasis on clear communication, is key to our successful FL intervention and support of student learning

Frank safford, the ideal of the practical. colombias struggle to form a technical élite

FRANK SAFFORD, The Ideal of the Practical. Colombias Struggle to form a Technical Élite. University of Texas, Austin, 1976. 373 páginas

Frank safford, aspectos del siglo xix en colombia.

FRANK SAFFORD, Aspectos del siglo XIX en Colombia. Ediciones Hombre Nuevo, Medellín, 1977