B ->\eta_c K(\eta_c^\prime K) decays in QCD factorization

We study the exclusive decays of $B$ meson into pseudoscalar charmonium states $\eta_c$ and $\eta_c^\prime$ within the QCD factorization approach and find that the nonfactorizable corrections to naive factorization are infrared safe at leading-twist order. The spectator interactions arising from the kaon twist-3 effects are formally power-suppressed but chirally and logarithmically enhanced. The theoretical decay rates are too small to accommodate the experimental data. On the other hand, we compare the theoretical calculations for $J/\psi, \psi^\prime$, and $\eta_c, \eta_c^\prime$, and find that the predicted relative decay rates of these four states are approximately compatible with experimental data.Comment: 8 pages, LaTex, 1 figure, one footnote and two references adde

Non-Native English-Speaking Teachers’ Legitimacy Negotiation in North American ELT Classrooms

The purpose of this paper is to examine the complexities of non-native English-speaking teachers’ (NNESTs’) legitimacy negotiation process in North American English language teaching (ELT) classrooms. This paper explores how NNESTs’ processes and outcomes of legitimacy negotiation can be impacted by unbalanced power relations, assigned-identity, and human agency. By drawing on various sociocultural theories, particularly power relations (Bourdieu, 1977; Holland, Lachicotte, Skinner, and Cain 2001; Norton, 2000), identity (Norton, 2000; Harklau, 2000; Morita, 2004), and human agency (Canagarajah, 1999; Norton & Toohey, 2001; Lantolf & Pavlenko, 2001), the analysis examines how the three factors—unbalanced power relations, assigned identity and personal agency manifest themselves in NNESTs’ attempting to cross barriers erected by language, culture, and racial boundaries

Carbon Dynamics in Aquatic Ecosystems in Response to Elevated Atmospheric CO2 and Altered Nutrients Availability

Aquatic ecosystems will experience altered inorganic carbon, nitrogen and phosphorous availability in the future due to elevated atmospheric CO2, stronger stratification and anthropogenic activities. Despite its importance in modulating global carbon cycles, how carbon dynamics in aquatic ecosystem response to the future global change remains largely unknown. Here we performed a chemostat experiment to study how equilibrium carbon dynamics response to elevated CO2 and altered N, P availability. Our results show that elevated CO2 led to enhanced photosynthetic carbon uptake and dissolved organic carbon (DOC) production. DOC occupied larger percentage in total organic carbon production in high CO2 environment. N addition stimulated biomass carbon accumulation. Collectively, in the future, high CO2 and low nutrient availability lead to high C: nutrient ratio in both biomass and dissolved organic carbon. It indicates a possible change in nutrient limitation and increase in recalcitrant dissolved organic carbon as long term carbon sequestration. Total carbon consumption remains unclear and will depend on the net effects of depleted nutrients and elevated CO2