Hampshire College

About: Hampshire College is a education organization based out in Amherst Center, Massachusetts, United States. It is known for research contribution in the topics: Genetic programming & Population. The organization has 461 authors who have published 998 publications receiving 40827 citations.

Uncharacterized Bacterial Structures Revealed by Electron Cryotomography.

Abstract: Electron cryotomography (ECT) can reveal the native structure and arrangement of macromolecular complexes inside intact cells. This technique has greatly advanced our understanding of the ultrastructure of bacterial cells. We now view bacteria as structurally complex assemblies of macromolecular machines rather than as undifferentiated bags of enzymes. To date, our group has applied ECT to nearly 90 different bacterial species, collecting more than 15,000 cryotomograms. In addition to known structures, we have observed, to our knowledge, several uncharacterized features in these tomograms. Some are completely novel structures; others expand the features or species range of known structure types. Here, we present a survey of these uncharacterized bacterial structures in the hopes of accelerating their identification and study, and furthering our understanding of the structural complexity of bacterial cells.IMPORTANCE Bacteria are more structurally complex than is commonly appreciated. Here we present a survey of previously uncharacterized structures that we observed in bacterial cells by electron cryotomography, structures that will initiate new lines of research investigating their identities and roles.

A stage is a stage is a stage: a direct comparison of two scoring systems.

Abstract: L. Kohlberg (1969) argued that his moral stages captured a developmental sequence specific to the moral domain. To explore that contention, the author compared stage assignments obtained with the Standard Issue Scoring System (A. Colby & L. Kohlberg, 1987a, 1987b) and those obtained with a generalized content-independent stage-scoring system called the Hierarchical Complexity Scoring System (T. L. Dawson, 2002a), on 637 moral judgment interviews (participants' ages ranged from 5 to 86 years). The correlation between stage scores produced with the 2 systems was .88. Although standard issue scoring and hierarchical complexity scoring often awarded different scores up to Kohlberg's Moral Stage 2/3, from his Moral Stage 3 onward, scores awarded with the two systems predominantly agreed. The author explores the implications for developmental research.

Comparing Teachers' Thinking about Promoting Students' Thinking

Abstract: Certain beliefs and theories of teachers outstanding at promoting students' thinking are compared to those of teachers less-than outstanding. Analysis reveals that differences exist between the two groups regarding their instructional goals, conceptions of thinking, and views on the dilemma of depth vs breadth of content coverage. Results may provide direction for pre- and in-service teacher training efforts which attempt to facilitate teachers' instructional practices in the area of thinking by engaging teachers' in reflection about practice.

Nitrogen fixation and respiration by root nodules of Alnus rubra Bong.: Effects of temperature and oxygen concentration*

Abstract: Using a root nodule cuvette and a continuous flow gas exchange system, we simultaneously measured the rates of carbon dioxide evolution, oxygen uptake and acetylene reduction by nodules of Alnus rubra. This system allowed us to measure the respiration rates of single nodules and to determine the effects of oxygen concentration and temperature on the energy cost of nitrogen fixation. Energy cost was virtually unchanged (2.8–3.5 moles of carbon dioxide or oxygen per mole of ethylene) from 16 to 26°C (pO2 = 20 kPa) while respiration and nitrogenase activity were highly temperature dependent. At temperatures below 16°C, nitrogenase activity decreased more than did respiration and as a result, energy cost rose sharply. Acetylene reduction ceased below 8°C. Inhibition of nitrogenase activity at low temperatures was rapidly reversed upon return to higher temperatures. At high temperatures (above 30°C) nitrogenase activity declined irreversibly, while respiration and energy cost increased.

"A good education is ...." The development of evaluative thought across the life span.

Abstract: The author uses a cognitive developmental approach to investigate educational conceptions, addressing the question, How does evaluative reasoning about education change over the course of cognitive development? The author conducted independent analyses of the developmental level and conceptual content of 246 interview performances of individuals aged 5 to 86 years. The developmental level of the interview performances was assessed with a content-general scoring system, the Hierarchical Complexity Scoring System. A Rasch analysis of the results revealed 6 developmental levels and provided support for invariant sequence, developmental spurts and plateaus, and similar developmental patterns for childhood and adulthood levels. The results of the subsequent analysis of the propositional content of the same interview texts were used to produce qualitative descriptions of changes in evaluative reasoning about education across the 6 levels identified in the data. Finally, descriptions constructed in this way, alt...