Single Leptoquark Production at e+e−e^+e^- and γγ\gamma\gamma Colliders

We consider single production of leptoquarks (LQ's) at $e^+e^-$ and $\gamma\gamma$ colliders, for two values of the centre-of-mass energy, $\sqrt{s}=500$ GeV and 1 TeV. We find that LQ's which couple within the first generation are observable for LQ masses almost up to the kinematic limit, both at $e^+e^-$ and $\gamma\gamma$ colliders, for the LQ coupling strength equal to $\alpha_{em}$. The cross sections for single production of $2^{nd}$- and $3^{rd}$-generation LQ's at $e^+e^-$ colliders are too small to be observable. In $\gamma\gamma$ collisions, on the other hand, $2^{nd}$-generation LQ's with masses much larger than $\sqrt{s}/2$ can be detected. However, $3^{rd}$-generation LQ's can be seen at $\gamma\gamma$ colliders only for masses at most $\sim\sqrt{s}/2$, making their observation more probable via the pair production mechanism.Comment: plain TeX, 14 pages, 6 figures (not included but available on request), some minor changes to the text, one reference added, figures and conclusions unchanged, UdeM-LPN-TH-93-152, McGill-93/2

Passive monitoring of anisotropy change associated with the Parkfield 2004 earthquake

International audienceWe investigate temporal variations in the polarization of surface waves determined using ambient seismic noise cross-correlations between station pairs at the time of the Mw 6.0 Parkfield earthquake of September 28, 2004. We use data recorded by the High Resolution Seismic Network's 3-component seismometers located along the San Andreas Fault. Our results show strong variations in azimuthal surface wave polarizations, Psi, for the paths containing station VARB, one of the closest stations to the San Andreas Fault, synchronous with the Parkfield earthquake. Concerning the other station pair, only smooth temporal variations of Y are observed. Two principal contributions to these changes in Y are identified and separated. They are: (1) slow and weak variations due to seasonal changes in the incident direction of seismic noise; and (2) strong and rapid rotations synchronous with the Parkfield earthquake for paths containing station VARB. Strong shifts in Y are interpreted in terms of changes in crack-induced anisotropy due to the co-seismic rotation of the stress field. Because these changes are only observed on paths containing station VARB, the anisotropic layer responsible for the changes is most likely localized around VARB in the shallow crust. These results suggest that the polarization of surface waves may be very sensitive to changes in the orientations of distributed cracks and that implementation of our technique on a routine basis may prove useful for monitoring stress changes deep within seismogenic zones. Citation: Durand, S., J. P. Montagner, P. Roux, F. Brenguier, R. M. Nadeau, and Y. Ricard (2011), Passive monitoring of anisotropy change associated with the Parkfield 2004 earthquake, Geophys. Res. Lett., 38, L13303, doi: 10.1029/2011GL047875

syn,syn-15,17-Di-2-naphthyl­hexa­cyclo­[10.2.1.13,10.15,8.02,11.04,9]hepta­decane deuterochloro­form monosolvate

The main molecule of the title compound, C37H36·CDCl3, is a hydro­carbon with two naphthalene segments attached to opposite ends of a rigid norbornylogous spacer with an overall structure that is approximately C-shaped. The dihedral angle between the naphthalene ring planes is 9.27 (7)°. The cleft that exists between the naphthalene rings is large enough that the compound crystallizes with a solvent mol­ecule (CDCl3) in the cleft. The CDCl3 solvent mol­ecule is present in two disordered orientations in a 3:2 ratio, each involving C—D⋯π to C 6 ring centers

Pre-service teachers’ attitudes toward students with behavioral difficulties: Associations with individual and education program characteristics

Teachers’ belief toward students with special educational needs (SEN) in the regular classroom is a condition that may influence the implementation of inclusive education. Nevertheless, some studies suggest that teachers’ attitudes or self-efficacy beliefs toward students with behavioral difficulties (BD) are quite negative, but much less emphasis has been placed on the factors and mechanisms contributing to these attitudes. This study investigates associations between pre-service teachers’ (PT) attitudes toward students with BD, PT’s individual characteristics including self-efficacy beliefs, and PT’s education program characteristics. Participants surveyed were 1,499 PT enrolled in a 4-year teacher education program (bachelor’s degree) in Quebec Province, Canada. Descriptive analysis showed that PT’s report generally positive attitudes toward students with BD on the three components of attitudes, while behavioral components were significantly more positive than the affective and cognitive components. Among the individual characteristics of PTs, the more advanced their academic level, the more negative their attitudes were on all three components. The characteristics related to the teacher education program (general vs. special) and the number of hours of courses on the BD revealed significant differences only on the cognitive component. Results of the mediation analysis further revealed that the association between the PT’s characteristics and the three components of attitudes was mediated by PT’s self-efficacy beliefs. Results are discussed considering their implications for the field of teacher education

A New Approach to Online Thickness Measurement of Thermal Spray Coatings

Peer reviewed: NoNRC publication: Ye

What Can We Learn About Leptoquarks At LEP200?

We investigate the discovery potential for first generation leptoquarks at the LEP200 $e^+e^-$ collider. We consider direct leptoquark searches using single leptoquark production via resolved photon contributions which offers a much higher kinematic limit than the more commonly considered leptoquark pair production process. Depending on the coupling strength of the leptoquark, search limits can be obtained to within a few GeV of $\sqrt{s}$. We also consider LQ limits that can be obtained from t-channel interferences effects in $e^+e^- \to hadrons$.Comment: Latex file uses revtex version 3, epsfig, and rotate, 5 postscript figures are attache