Existence of a new force in colloidal systems —Hydrophobic attraction between macroscopic surfaces

Colloids play an important role in our modern lives. In this article, we briefly discuss various forces that are known to operate between colloidal particles and then take the reader through the discovery of a new, strong and long ranged force operating between hydrophobic particles/surfaces. Characteristics of the new force and some promising theories proposed in the literature to explain its origin are also discussed; the origin of the new force is not yet resolved, however.     

Representation of time in time-place learning

Ordinal, interval, and circadian mechanisms of solving a time-place task were tested. Rats searched for food twice in the morning and once in the afternoon (Group AB-C,n=5) or once in the morning and twice in the afternoon (Group A-BC,n=5) in a box with four food troughs. The location of the food depended on the time of day in a 12:12-h light:dark cycle. Acquisition was documented by foodsite inspections at the correct locations prior to food availability. On nonrewarded probes, the time of the middle search (B) was shifted late (for Group AB-C) or early (for Group A-BC). The rats visited Location B at chance, contrary to an ordinal mechanism. When the posttesting meal and light-dark transitions were omitted, the rats visited correct locations with impaired performance but at abovechance levels on nonrewarded probes. The results are consistent with interval and circadian representations of time.     

Heterogeneous UV/Fenton catalytic degradation of wastewater containing phenol with Fe-Cu-Mn-Y catalyst

The heterogeneous UV/Fenton process with the appropriate amount of Fe-Mn-Cu-Y as catalyst was developed and various operation conditions for the degradation of phenol were evaluated. The results indicated that by using the heterogeneous UV/Fenton process, the CODcr removal rate reached almost 100% for wastewater containing phenol. Compared with the homogeneous process, the developed catalyst could be used at wider pH range in the UV/Fenton process. Comparison of various heterogeneous process showed that heterogeneous UV/Fenton process was best. The heterogeneous UV/Fenton process with Fe-Mn-Cu-Y catalyst is highly efficient in degrading various organic pollutants.     

From Research to Practice and Back: The Animation Tutor Project

The Animation Tutor^TM is a curriculum project that uses software to supplement instruction in courses such as intermediate algebra. Its purpose is to ground mathematical reasoning in concrete experiences through the use of interactive animation and the virtual manipulation of objects. This article summarizes how the project has progressed from research to practice and back. The first section shows how research helped implement six instructional objectives: emphasize interactivity with reflection, integrate multiple representations, reduce cognitive load, facilitate transfer, replace ineffective static images with animated images, and provide domain-specific knowledge. The last section illustrates the reciprocal nature of research and practice by describing how formative evaluations of the Animation Tutor^TM program led to laboratory studies aimed at improving instructional materials and student strategies.     

A New Way of Thinking about Social Location in Science

The Durkheimian concept of the density of social relationships may prove more fruitful than the historical materialist notion of a social hierarchy for thinking about the social location of epistemic agents in science. To define a scientist’s social location in terms of the density of her professional relationships with other scientists permits us to give a more precise characterization of marginalization and thus to formulate more testable hypotheses about marginalized groups in science. The notion of social density helps to explain not only how some individual scientists are more likely than others to get a hearing for their ideas, but also how scientific inquiry flourishes more in some societies than in others.

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A Cultural Perspective on Professional Beliefs of Childcare Teachers

Preschool is an institution for cultural preservation, which responds to social change. Guided by this assumption, this study used a recent video of Chinese preschool in conjunction with the questionnaire from Preschool in Three Cultures, a study by Joseph Tobin and his colleagues in the 1980s, to examine the cultural and professional beliefs of three groups of U.S. early childhood educators (preservice, inservice non-Head Start, and inservice Head Start). We examined participants’ cultural beliefs, critical comments on the preschool, and group differences in their comments. Results show that participants’ beliefs about necessary qualities for a teacher remained stable from the 1980s in the U.S. But a shift occurred in beliefs about why society needs preschools. More education and longer employment were linked significantly to more critical comments of Chinese practice. There was a marked difference in professional and cultural beliefs by educators’ group affiliations.

Geotechnical research on Jiangnan Tu-Dun tomb historical remains in China

Geotechnical research on historical remains can provide new data and distinctive viewpoint for research on soil mechanics. Two Jiangnan Tu-Dun tombs historical remains were investigated by means of in situ and laboratory geotechnical tests. In the present paper the geotechnical properties of these man-made earthworks, especially ageing effect on consolidation and direct shear, and compaction properties of earth fill are discussed.     

Quality Assurance of Higher Education in Transition Countries: Accreditation -- Accountability and Assessment

One issue facing countries in transition concerns how to ensure quality for a broader and more diverse set of institutions. Quality assurance processes (i.e. accreditation, accountability and assessment) have particular relevance today as higher education undergoes dramatic changes in countries in transition, as the world becomes more internationalised, and as private higher education institutions increase in number and enrol increasing numbers of students. Three questions emerge. Do differences among transition countries relative to central control prior to independence explain the current set of quality assurance mechanisms? Has the growth of private higher education in transition countries affected how quality assurance is conceptualised? Have quality assurance mechanisms been affected by the opening of branch campuses in transition countries?     

Woodward’s synthesis of vitamin B<Subscript>12</Subscript>

The synthesis of this molecule was a landmark in organic synthesis. It involved the masterful control of shapes of molecules to create 9 chiral centres with known absolute and relative configurations. The concepts of absolute and induced asymmetric synthesis are here explained.