Focused and defocused retinal images with Bessel and axicon pupil functions.

Retinal image light distributions in a standard optical model of a diffraction-limited eye with round pupils are presented for several patterns of amplitude and phase modulation of the light admitted into the eye. Of special interest are circularly symmetrical configurations of truncated Bessel amplitude transmission functions, and of light subjected to axicon deviation. It is shown by several examples that this kind of beam shaping allows generation of retinal imagery, which can be more robust to defocus while maintaining minimal image degradation, and it points to situations of two separate zones simultaneously in sharp focus, several diopters apart

Hering Hermeneutics: Supplement to Translation and Commentary of Hering (1899) by Strasburger et al.

Strasburger et al.'s welcome translation of Hering's seminal paper, and reminder of what Hering actually said about eye movements and spatial averaging in vernier acuity, is supplemented by references to further trends on how the subject has evolved to the present state of knowledge

Education that Matters

Forty years ago, the Summer Olympics were being held in Montreal, the CN Tower opened to the public, and Canadians were introduced to a bite-sized piece of fried dough called a Timbit. “I Write the Songs” by Barry Manilow hit No. 1 on the music charts, and Steve Wozniak and Steve Jobs started a small company called Apple Computer in the garage of Jobs’s parents’ house in Cupertino, California. The same year, the Canadian Society for the Study of Education (CSSE), Canada’s premier association for professors, students, and researchers in education, published the first issue (January 1976) of the Canadian Journal of Education (CJE). It was distributed free to all CSSE members (non-members could buy one for $2!). In his opening editorial, founding editor Ronald G. Ragsdale expressed his hope that Canadian educators would use CJE as a “national forum for the exchange of ideas…a written record of the issues in education of concern to Canadians” (Ragsdale, 1976, p. 1)

Confronting Power: Success Isn’t Everything—But It’s Not Nothing Either. A Response to “Beyond the Catch-22 of School-Based Social Action Programs: Toward a More Pragmatic Approach for Dealing with Power”

Fehrman and Schutz contend that the fine balance between having students experience real-world obstacles to social change and having them learn how to navigate around those obstacles can be achieved by having adults both pre-select community action projects that are both possible and meaningful to ensure a modicum of success, and jump in and redirect wayward efforts when necessary to get them back on a trajectory aimed at a positive outcome. I agree. I also suggest that other factors are significant as well, namely the purposeful nurturing of a sense of community and hopefulness. Finally, I point out that adult intervention and democratic teaching are in no way mutually exclusive, especially by any standard John Dewey might have suggested

COMMUNITY SERVICE LEARNING: Pursuing Jewish Ideals of Compassion and Justice

Service learning involves community service activities tied to the academic curriculum. It has strong roots in the progressive philosophy of turn-of-the-century educators like John Dewey, Harold Rugg, and William Kilpatrick, but its Widespread popularity is a contemporary phenomenon. A recent study by the National Center for Education Statistics reveals that 83 percent of high schools currently offer community service opportunities (compared with 27 percent in 1984). School-based service learning is among the fastest growing and popular education reforms of the past three decades. Jewish educators have seen simila

Active Thermal Control System Development for Exploration

All space vehicles or habitats require thermal management to maintain a safe and operational environment for both crew and hardware. Active Thermal Control Systems (ATCS) perform the functions of acquiring heat from both crew and hardware within a vehicle, transporting that heat throughout the vehicle, and finally rejecting that energy into space. Almost all of the energy used in a space vehicle eventually turns into heat, which must be rejected in order to maintain an energy balance and temperature control of the vehicle. For crewed vehicles, Active Thermal Control Systems are pumped fluid loops that are made up of components designed to perform these functions. NASA has been actively developing technologies that will enable future missions or will provide significant improvements over the state of the art technologies. These technologies have are targeted for application on the Crew Exploration Vehicle (CEV), or Orion, and a Lunar Surface Access Module (LSAM). The technologies that have been selected and are currently under development include: fluids that enable single loop ATCS architectures, a gravity insensitive vapor compression cycle heat pump, a sublimator with reduced sensitivity to feedwater contamination, an evaporative heat sink that can operate in multiple ambient pressure environments, a compact spray evaporator, and lightweight radiators that take advantage of carbon composites and advanced optical coatings

INTRODUCTION: DEMOCRACY AND EDUCATION

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The 30/20 GHz fixed communications systems service demand assessment. Volume 2: Main report

A forecast of demand for telecommunications services through the year 2000 is presented with particular reference to demand for satellite communications. Estimates of demand are provided for voice, video, and data services and for various subcategories of these services. The results are converted to a common digital measure in terms of terabits per year and aggregated to obtain total demand projections

Service Learning as Democratic Action

It is often said that today\u27s youth will be called on to solve tomorrow\u27s problems. Schools provide essential preparation for this task. Despite the rhetoric, curriculum that considers the nature of social problems and ways youth might respond as citizens rarely gets center stage. Rather than focusing on ways youth might participate through democratic institutions to foster a better society, curricular discussions focus on the acquisition of academic and vocational skills. To the extent that the democratic purposes of education are raised, educators emphasize conveying knowledge regarding U.S. history and government structures and exercises in which students simulate the operations of various public institutions such as courts and legislatures