Abstract: [1] Ice resistance to tensile fracture influences surface morphodynamics on outer planetary satellites such as Titan, yet measurements of tensile strength and fracture toughness of polycrystalline water ice at temperatures below terrestrial conditions (<220 K) have not been previously reported. We investigated these parameters from 260 K to 110 K using a walk-in freezer, and chilling by dry ice and liquid nitrogen. We also investigated the influence of solid impurity concentration and the spread in crystal grain size distribution. Although fracture toughness showed no sensitivity to temperature, we find that tensile strength increases with decreasing temperature at 7 kPa K−1for all ice types tested. For pure water ice, samples made from uniform-sized seed crystals were stronger than mixed-grain-size ice, suggesting that strength is limited by the coarse tail of the size distribution. Samples tested submerged in liquid ethanol were 0.45 MPa weaker than in air; increasing porosity reduced tensile strength. Tensile strength increased linearly with concentration of urea, basalt and ammonium sulfate. These results suggest that on Titan and other icy satellites, the tensile strength of fine-grained polycrystalline water ice containing solid impurities may be several times greater than the 1 MPa value commonly used in modeling. For low strain rate processes where fracture propagation rather than fracture initiation limits strength, a temperature invariant fracture toughness of 0.15 MPa m1/2 is appropriate. Understanding ice diagenesis on Titan, and the resulting composition, grain size distribution, and porosity, is needed to accurately model surface processes that are limited by ice resistance to fracture.

Abstract: Understanding how children perceive and interact with teachable agents (systems where children learn through teaching a synthetic character embedded in an intelligent tutoring system) can provide insight into the effects of so-cial interaction on learning with intelligent tutoring systems. We describe results from a think-aloud study where children were instructed to narrate their experience teaching Stacy, an agent who can learn to solve linear equations with the student's help. We found treating her as a partner, primarily through aligning oneself with Stacy using pronouns like you or we rather than she or it significantly correlates with student learning, as do playful face-threatening comments such as teasing, while elaborate explanations of Stacy's behavior in the third-person and formal tutoring statements reduce learning gains. Additionally, we found that the agent's mistakes were a significant predictor for students shifting away from alignment with the agent.

Abstract: This study puts forward a variable clique overlap model for identifying information communities, or potentially overlapping subgroups of network actors among whom reinforced independent links ensure efficient communication. We posit that the intensity of communication between individuals in information communities is greater than in other areas of the network. Empirical tests show that the variable clique overlap model is more useful for identifying groups of individuals that have strong internal relationships in closed networks than those defined by more general models of network closure. These findings extend the scope of network closure effects proposed by other researchers working with communication networks using social network methods and approaches, a tradition which emphasizes ties between organizations, groups, individuals, and the external environment.

Abstract: The thermosolvatochromism of nitrospiropyran free and bound to cyclodextrin was studied in dimethylsulfoxide (DMSO)–water binary solvent systems. Spiropyran was interconverted to merocyanine by heating the sample to 55 °C. The merocyanine (MC) was converted back to spiropyran (SP) either by cooling the sample to room temperature or irradiating the sample with a visible light emitting diode. Steady state absorption spectra of SP and MC samples in the free state and bound to cyclodextrin were obtained in several DMSO–water binary solutions. Emission spectra of MC both free and cyclodextrin-bound were also acquired. Blue-shifted absorption and emission spectra of the studied molecules with increasing solvent polarity suggest that the dipole moments of free and bound merocyanines are higher in the ground state compared to the excited state. Merocyanine dipole moments in the ground and excited states were determined using thermosolvatochromism measurements and the Lippert–Mataga, Bakhshiev, and Kawski–Chamma–V...

Abstract: During his travels through the United States in the early-nineteenth century, Alexis de Tocqueville, in his reflections on civil society and attempts to capture the essence of its culture and values, famously noted the American spirit of voluntary cooperation. At a time when the national government was truly small, Tocqueville (1899) observed that, “When an American asks for the co-operation of his fellow-citizens, it is seldom refused, and I have often seen it afforded spontaneously andwith great goodwill . . . The Americans, who are always cold and often coarse in their manners, seldom show insensibility; and if they do not proffer services eagerly, yet they do not refuse to render them” (p. 185). Due largely to the economic crisis of the Great Recession that began in late 2007 and whose effects continue to the present day, we are currently witnessing deep cutbacks in social services and staunch opposition to tax increases (National Public Radio 2011; Rasmussen Reports 2011). As a consequence, it is no longer tenable to believe that themost creative solutions to society’s most vexing problems will come from government programs. Obviously the state has a duty to play a major role in addressing societal issues on a large scale, particularly in the areas of public safety, public health, and unemployment. But given today’s strained political and economic climate, nongovernmental voluntary effort is clearly the more reasonable and sensible strategy to take. The fact is that there are currently tens of thousands of citizens involved in voluntary community service throughout the country (Corporation for National and Community Service 2011). Indeed, the national volunteer rate in 2010 was 26 percent, with nearly 63 million volunteers serving. These volunteers dedicated over 8 billion hours to volunteer service, and the economic value of this service was almost $173 billion (Corporation for National and Community Service 2011). What is more, no less than 26 percent of college students volunteered in 2010, and over 3 million of them dedicated over 300 million hours of service to communities across the country, primarily in activities involving youth mentoring, fundraising, and teaching and tutoring (Corporation for National and Community Service 2011). This service work is being done by many ordinary people who are picking up the slack for a city, a state, a nation unwilling or unable to attend to many critical matters that directly affect thousands, even millions, of people (Coles 1993). I contend that we have now entered a new era in this country, one characterized by a culture of service—involving various forms of civic engagement, community service, and volunteerism— that allows people, as citizens, to work together to ease or mitigate the predicaments and uncertainties created by poverty, hunger, racism, sexism, epidemics, calamities, and so on.

Abstract: Site-selective spectroscopy is a tool that can be used to uncover the presence of multiple sites available to optically active ions in host lattices. In this Article, we present techniques that can be applied to appraise the different sites that may occur in systems where charge compensation is required or in systems where such compensation is not present. We then consider some garnet crystals doped with chromium ions. For the Cr-doped garnets (YAG, GGG, GSGG, and CYMGG), we present luminescence and lifetime data over a wide temperature range, and infer not only the presence of different centers, but also the interaction among them as a function of temperature.

Abstract: Objectives.CDC 2006 recommendations for new HIV testing methods in U.S. health-care settings (opt-out approach, general medical consent, and optional prevention counseling) have been the subject of...

Abstract: It is well appreciated that historical and ecological processes are important determinates of freshwater biogeographic assemblages. Phylogeography can potentially lend important insights into the relative contribution of historical processes in biogeography. However, the extent that phylogeography reflects historical patterns of drainage connection may depend in large part on the dispersal capability of the species. Here, we test the hypothesis that due to their relatively greater dispersal capabilities, the neotropical cichlid species Andinoacara coeruleopunctatus will display a phylogeographic pattern that differs from previously described biogeographic assemblages in this important region. Based on an analysis of 318 individuals using mtDNA ATPase 6/8 sequence and restriction fragment length polymorphism data, we found eight distinct clades that are closely associated with biogeographic patterns. The branching patterns among the clades and a Bayesian clock analysis suggest a relatively rapid colonization and diversification among drainages in the emergent Isthmus of Panama followed by the coalescing of some drainages due to historical connections. We also present evidence for extensive cross-cordillera sharing of clades in central Panama and the Canal region. Our results suggest that contemporary phylogeographic patterns and diversification in Lower Central American fishes reflect an interaction of historical drainage connections, dispersal, and demographic processes.

Abstract: At the 1904 St. Louis World's Fair, 1100 Filipino ‘natives’ were used as human displays to argue for the colonial enterprise in the Philippines. Seventy years later, the Marcos regime staged Kasaysayan ng Lahi (History of the Race), a mass ceremony that reworked the visual, performative and commercial dynamics of the 1904 colonial exposition to promote heritage tourism in the Philippines. While the use of human displays in colonial expositions has been well documented and analyzed as a constitutive element of a Eurocentric ‘exhibitionary complex’, its uptake in developing nations seeking entry into an emergent cultural economy has yet to be explored. This article places critical analyses of colonial expositions, human displays and heritage tourism in productive dialogue, and examines the continuities and discontinuities between the Philippine exhibit at the 1904 St. Louis World's Fair and the 1974 staging of Kasaysayan ng Lahi by the Marcos regime. Against established views of ‘staged authenticities’ as e...

Abstract: This article seeks to examine and compare the parameters of discourse of contemporary Russian and Chinese political elites regarding democracy. It focuses on the question of the extent to which Russian and Chinese political elites have acknowledged the validity of constructs of Western liberal democracy. I argue that democracy is conceived instrumentally as a means to economic modernisation. The central dilemma facing both leaderships has been how to adapt elements of the liberal democratic model, while ensuring the maintenance of vertical political controls.

Abstract: Palmer, S., & Schloss, K. (2010). An ecological valence theory of human color preference. Proceedings of the National Academy of Sciences, 107(9), 8877-8882. Schloss, K., Poggesi, R., & Palmer, S. (2011). E ects of university a liation and “school spirit” on color preferences: Berkeley versus Stanford. Psychonomic Bulletin and Review, 18(3), 498-504. Taylor, C., Cli ord, A., & Franklin, A. (2011, VSS poster). Mere exposure in uences male colour preference, yet female colour preference is resistant to change. Journal of Vision, 11(11), article 387. Claudia D’Adamo Elaine Grulke Kerry Kenneally Thomas Langlois Teikyo Mowchan Tongbo Sui Michaela Superson Rosa Poggesi Thanks to: This longitudinal study undertaken over the course of a year provides evidence for the Ecological Valence Theory of color preference (Palmer & Schloss, 2010), since color preference changed with season in an environment where there are substantial seasonal color variations in the natural environment. The most pronounced di erences in color preference were found between spring and fall. This may be due to the more vivid colors present in New England falls (e.g., oranges, reds, yellows) and springs (e.g., greens). There were also gender di erences in color preference across seasons. Males appeared to vary more in their preferences, while females were more stable. This is in accord with other studies showing that color preference in males may be more in uenced by their surroundings. Taylor , Cli ord, & Franklin (2011) found that males were more susceptible to mere exposure e ects on color preferences whereas females were una ected. Seasonal Di erences in Color Preferences

Abstract: Leiden, the Netherlands: Brill, 2006, 2007. xxv + 777 pp.; xix + 573 pp. $458 hardcover. The Swiss psychiatrist C. G. Jung distinguished two kinds of psychology of religion—one focused on content, ...

Abstract: of timing and detail, rather than of fundamental aims and objectives. The most common thread that runs throughout the period is the question of resources: student numbers have consistently outrun the level of growth in the economy, leading to a competition between policy objectives across the public sector of the economy. One interpretation of the development of higher education policy in Britain since 1970 is that it is simply a series of short-term adjustments to accommodate unavoidable growth within an inflexible budget framework. Taylor and Steele would not see it this way and are much more interested in the high ground of political and sociological theory, which makes their book such a stimulating read. They hint that they intend to do a follow-up study of the Blair/Brown years. They should be strongly encouraged to do so.