The Future of Communication Education in the Community College

This article discusses the future of communication education in community colleges in the U.S. Recently, business and political leaders have begun to take note of the important role of community colleges within higher education. Bill Gates, chairman of the Microsoft Corp., firmly stated that community colleges are becoming absolutely critical in the information age. He continued by adding, The more I\u27ve learned about the community-college system throughout the United States, the more I\u27ve been impressed. President Bill Clinton\u27s vision of expanding education for all Americans to include grades 13 and 14 moves the community college to a more visible location in the fabric of American education. Perhaps surprisingly to some, community colleges have become significant players in the educational arena. Over 9 million credit students are enrolled in our nation\u27s 1,130 community colleges. Almost half (46%) of all first-time college freshmen attend community colleges. The majority of all African American students (46%) and Hispanic students (55%) in higher education are found in community colleges. Historically, community colleges evolved from junior colleges, providing access to higher education for local populations, into a more eclectic mix of institutions continuing to provide access, but with a wider range of options. As a result, there is no universal agreement regarding the role of the community college. Regardless of in which corner a community college currently resides, the evolutionary process will continue to mold and reshape today\u27s community colleges

Tiefenprofiluntersuchungen an ionenleitenden Gläsern mittels Flugzeit-Sekundärionen-Massenspektrometrie (ToF-SIMS)

In dieser Arbeit wird das Verhalten von ionenleitenden, bioaktiven Gläsern und Polymermembranen untersucht. Dabei kommt hauptsächlich die Flugzeit-Sekundärionen-Massenspektrometrie (ToF-SIMS) zum Einsatz. Damit kann eine dreidimensionale Darstellung der Elementverteilung in einer Probe geschaffen werden. Nach der Synthese von bioabsorbierbaren Gläsern der allgemeinen Formel CaXA (X% CaO; (55-X)% A2O; 45% P2O5 mit X = 20, 30, 40, 50 und A = Na, K, Rb, Cs) und dem bioaktiven Glas 46S4 (46,4% SiO2; 25,2% Na2O; 25,2% CaO; 3,2% P2O5) werden zwei unterschiedliche Experimente daran angewendet. Zum einen wird eine elektro-thermische Polarisation durchgeführt. Dabei wird bei erhöhter Temperatur ein elektrisches Feld an das Glas angelegt, was zur Ausbildung einer Natrium-Verarmungszone unter der Anodenseite des Glases führt. Durch eine Kombination von Impedanzspektroskopie, Depolarisationsstrommessungen und ToF-SIMS-Tiefenprofilierung kann die Bildung der Verarmungszone beobachtet werden, sowie deren Dicke bestimmt und die darin gespeicherte Ladung ermittelt werden. Anschließend wird der Einfluss der Polarisation auf die Bioaktivität der Gläser überprüft. Bioaktive Gläser sind in der Lage, beim Kontakt mit Gewebe oder Knochen des menschlichen Körpers knochenähnliches Material an ihrer Oberfläche auszubilden und so eine feste Bindung mit dem Gewebe einzugehen. Für die Untersuchung der Bioaktivität werden sie für einige Zeit in eine Lösung eingelegt, die den Ionengehalt und pH-Wert von Gewebsflüssigkeit genau nachbildet (simulierte Körperflüssigkeit). Die anschließende Analyse der Oberfläche zeigt einen deutlichen Einfluss der Polarisation auf die Bioaktivität und das Löslichkeitsverhalten der Gläser. Zum anderen wird die Technik des bombardement-induzierten Ionentransports (BIIT) auf die Gläser und Polymermembran angewendet. Dabei werden mit Hilfe eines geleiteten Ionenstrahls Alkaliionen auf der Oberfläche deponiert. Dadurch entsteht ein elektrischer Potentialgradient, der zur Wanderung der Ionen durch das Material führt. Mit ToF-SIMS kann dieses Diffusionsprofil gemessen werden. Anschließend wird mit Hilfe der Nernst-Planck-Poisson-Gleichungen das Tiefenprofil mit der Theorie verglichen. Dabei können die konzentrationsabhängigen Diffusionskoeffizienten der Alkaliionen berechnet werden

AC impedance of poled glass during de-poling

It has been observed in the literature that when the DC poling voltage is removed at the end of the poling process in glass in a so called de-poling experiment, the small signal AC impedance as measured by impedance spectroscopy increases immediately. It is shown that this effect can be explained if the DC voltage causes nonlinear ionic conduction to occur in the poled layer. The DC field changes the barrier height over which ions have to jump from one site to another and this also effects the AC resistance; by removing the DC field the original barrier height is restored thus increasing the AC resistance. Analysis of experimental data using poled soda-lime glass supports this interpretation

A new generation of 99.999% enriched 28Si single crystals for the determination of Avogadro's constant

A metrological challenge is currently underway to replace the present definition of the kilogram. One prerequisite for this is that the Avogadro constant, NA, which defines the number of atoms in a mole, needs to be determined with a relative uncertainty of better than 2  ×  10−8. The method applied in this case is based on the x-ray crystal density experiment using silicon crystals. The first attempt, in which silicon of natural isotopic composition was used, failed. The solution chosen subsequently was the usage of silicon highly enriched in 28Si from Russia. First, this paper reviews previous efforts from the very first beginnings to an international collaboration with the goal of producing a 28Si single crystal with a mass of 5 kg, an enrichment greater than 0.9999 and of sufficient chemical purity. Then the paper describes the activities of a follow-up project, conducted by PTB, to produce a new generation of highly enriched silicon in order to demonstrate the quasi-industrial and reliable production of more than 12 kg of the 28Si material with enrichments of five nines. The intention of this project is also to show the availability of 28Si single crystals as a guarantee for the future realisation of the redefined kilogram

Improved measurement results for the Avogadro constant using a 28Si-enriched crystal

New results are reported from an ongoing international research effort to accurately determine the Avogadro constant by counting the atoms in an isotopically enriched silicon crystal. The surfaces of two 28Si-enriched spheres were decontaminated and reworked in order to produce an outer surface without metal contamination and improved sphericity. New measurements were then made on these two reconditioned spheres using improved methods and apparatuses. When combined with other recently refined parameter measurements, the Avogadro constant derived from these new results has a value of $N_A = 6.022 140 76(12) \times 10^{23}$ mol$^{-1}$. The X-ray crystal density method has thus achieved the target relative standard uncertainty of $2.0 \times 10^{-8}$ necessary for the realization of the definition of the new kilogram.Comment: postprint, 22 page, 3 figures, 14 table

Differences in affective learning and perceived immediacy of instructor between traditional college classrooms and classrooms incorporating student use of computer-mediated communication

The purpose of this quasi-experimental study was to determine whether community college students enrolled in Interpersonal Communication who utilize the technological aid of computer-mediated communication in the classroom have different perceptions of their affective learning and their instructor\u27s immediacy than do students who do not utilize computer-mediated communication in the classroom. The methodology used to address the issue was a post test-only control group design, with students completing the affective learning scale, the nonverbal immediacy scale, and the verbal immediacy scale. Results showed no significant differences were found between the treatment and control groups on either immediacy scale (verbal or nonverbal). Significant differences did exist between the treatment and control groups for affective learning. Correlation findings showed that affective learning was significantly correlated to verbal immediacy. Also, nonverbal immediacy was significantly correlated to verbal immediacy. Affective learning was also correlated to nonverbal immediac