Red fluorescence and 3-12 micron emission in NGC 2023, HD 44179, M 82, and Lynds 1780

A red excess observed in the Red Rectangle (HD 44179), was attributed to a possible molecular fluorescence mechanism was discovered in NGC 2023 and analyzed in subsequent work in this and other nebulae. An unexpected red light excess was also noticed in a high latitude dark cloud L 1780. The fluorescence was attributed to hydrogenated amorphous carbon by Duley (1985), on the basis of laboratory work. Alternatively, transitions between electronic states of free polycyclic aromatic hydrocarbon molecules, by-passing the cascade along the vibrational states was considered. In L 1780, the red excess was related to the 12 micron emission detected by IRAS. A quantitative comparison of the intensity of the red fluorescence and that of the 3 to 12 micron features is thus warranted in helping assess the physical properties of large interstellar molecules. The red fluorescence radiation, F(R), appears as a bump on the spectra between 0.6 and 0.9 micron. Values were deduced from the spectra for HD 44179, and for the high latitude cloud L 1780. Corrections for the extinction, both interstellar and internal to the nebulae, were included. The 3 to 12 micron brightness, F(IR), was obtained through integration of the spectra for NGC 2023, and for HD 44179 after removal of a smooth continuum due to hot large grains. The values of the ratio of fluorescence flux to the infrared flux, F(R)/F(IR), are summarized. Red fluorescence and infrared radiation are two separate ways to access to the size of the molecules through observation, and it is rewarding that both approaches give similar results. These findings bring a striking coherence into the physical description of the particles, and add further support to the initial attribution of the infrared features to polycyclic aromatic hydrocarbons (PAHs)

Improving Participation in a Pluralistic Democracy through a Cosmopolitan Approach to Social Studies Education

Democracy in a pluralistic society depends on individual and group participation. One of the goals of social studies education is to instill a sense of civic efficacy. Some people are able to consistently participate in democratic processes, yet many are not able to because of cultural and societal marginalization. The assimilationist approach to building national unity forces individuals to give up their cultural identity in order to be accepted by the mainstream culture. This loss of identity can cause resentment and alienation, which leads to a fragmenting of the national society, and decreasing national unity. Globalization has increased the diversity of American society, and ignoring the relationships that individuals have in their local, national, and global communities can contribute to the marginalization of diverse cultural groups. A cosmopolitan approach to social studies education can reinforce democratic principles that are valued in the United States, by acknowledging the ethnic and cultural diversity and multicultural citizenship. This can increase national unity and individual civic efficacy while also celebrating the diversity found in our communities

Programs and Practices: Students’ Historical Understandings in International Baccalaureate, Advanced Placement and Regular World History Courses

World history has become increasingly important and has often been a required course for high school students in the United States. This multi-case study provides examples and descriptions of students’ demonstration of historical understandings. It also includes multiple perspectives and experiences of world history students and teachers, and analyses of International Baccalaureate, Advanced Placement, and regular World History program curricula. Methods and data sources used in this study included participant observations, focus group interviews, student artifacts, and program curriculum documents. The types of historical understanding varied among the three World History programs’ courses, ranging from identifying cause and effect relationships to the inclusion of multiple perspectives in history. The most unique type of historical understanding displayed by students was the acknowledgement of historical humility in International Baccalaureate History. Findings of this study have implications for pedagogical and curricular approaches to teaching world history.

Quasipotentials with more than two variables: new evaluation at equilibrium points of the drift

The relevant quasipotential near an equilibrium point is determined by a new linear matrix equation, with less unknowns than an existing (possibly nonlinear) one. This also assures the asymptotic fulfillment of the Fokker-Planck equation, even globally due to the second term in the noise strength. An auxiliary result for the exit problem is derived as well.Comment: Some results of arXiv.org/abs/1204.4681 are extended to more than 2 variables. Former title: "Nonminimum quasipotentials for the actual weak noise solution of Fokker-Planck equations